Activity of afatinib in patients with NSCLC harboring novel uncommon EGFR mutations with or without co-mutations: a case report

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) represent first-line standard of care in unresectable EGFR mutation-positive (EGFRm+) non-small cell lung cancer (NSCLC). However, 10-20% of patients with EGFRm+ NSCLC have uncommon EGFR variants, defined as mutations other than L858R substitutions or exon 19 deletions. NSCLC harboring uncommon EGFR mutations may demonstrate lower sensitivity to targeted agents than NSCLC with L858R or exon 19 deletion mutations. Prospective clinical trial data in patients with NSCLC uncommon EGFR mutations are lacking. Afatinib is a second-generation TKI and the only Food and Drug Administration-approved drug for some of the more prevalent uncommon EGFR mutations. We present a series of seven case reports describing clinical outcomes in afatinib-treated patients with NSCLC harboring a diverse range of extremely rare mutations with or without co-mutations affecting other genes. EGFR alterations included compound mutations, P-loop αC-helix compressing mutations, and novel substitution mutations. We also present a case with NSCLC harboring a novel EGFR::CCDC6 gene fusion. Overall, the patients responded well to afatinib, including radiologic partial responses in six patients during treatment. Responses were durable for three patients. The cases presented are in line with a growing body of clinical and preclinical evidence that indicating that NSCLC with various uncommon EGFR mutations, with or without co-mutations, may be sensitive to afatinib.

ATF3 characterizes aggressive drug-tolerant persister cells in HGSOC

High-grade serous ovarian cancer (HGSOC) represents the most common and lethal subtype of ovarian cancer. Despite initial response to platinum-based standard therapy, patients commonly suffer from relapse that likely originates from drug-tolerant persister (DTP) cells. We generated isogenic clones of treatment-naïve and cisplatin-tolerant persister HGSOC cells. In addition, single-cell RNA sequencing of barcoded cells was performed in a xenograft model with HGSOC cell lines after platinum-based therapy. Published single-cell RNA-sequencing data from neo-adjuvant and non-treated HGSOC patients and patient data from TCGA were analyzed. DTP-derived cells exhibited morphological alterations and upregulation of epithelial-mesenchymal transition (EMT) markers. An aggressive subpopulation of DTP-derived cells showed high expression of the stress marker ATF3. Knockdown of ATF3 enhanced the sensitivity of aggressive DTP-derived cells to cisplatin-induced cell death, implying a role for ATF3 stress response in promoting a drug tolerant persister cell state. Furthermore, single cell lineage tracing to detect transcriptional changes in a HGSOC cell line-derived xenograft relapse model showed that cells derived from relapsed solid tumors express increased levels of EMT and multiple endoplasmic reticulum (ER) stress markers, including ATF3. Single cell RNA sequencing of epithelial cells from four HGSOC patients also identified a small cell population resembling DTP cells in all samples. Moreover, analysis of TCGA data from 259 HGSOC patients revealed a significant progression-free survival advantage for patients with low expression of the ATF3-associated partial EMT genes. These findings suggest that increased ATF3 expression together with partial EMT promote the development of aggressive DTP, and thereby relapse in HGSOC patients.

Sotorasib in KRAS G12C-mutated non-small cell lung cancer: A multicenter real-world experience from the compassionate use program in Germany

BACKGROUND

Sotorasib is a first-in-class KRAS p.G12C-inhibitor that has entered clinical trials in pretreated patients with non-small cell lung cancer (NSCLC) in 2018. First response rates were promising in the CodeBreaK trials. It remains unclear whether response to sotorasib and outcomes differ in a real-world setting when including patients underrepresented in clinical trials.

METHODS

Patients with KRAS p.G12C-mutated advanced or metastatic NSCLC received sotorasib within the German multicenter sotorasib compassionate use program between 2020 to 2022. Data on efficacy, tolerability, and survival were analyzed in the full cohort and in subgroups of special interest such as co-occurring mutations and across PD-L1 expression levels.

RESULTS

We analyzed 163 patients who received sotorasib after a median of two treatment lines (range, 0 to 7). Every fourth patient had a poor performance status and 38% had brain metastases (BM). The objective response rate was 38.7%. The median overall survival was 9.8 months (95% CI, 6.5 to not reached). Median real-world (rw) progression-free survival was 4.8 months (9% CI, 3.9 to 5.9). Dose reductions and permanent discontinuation were necessary in 35 (21.5%) and 7 (4.3%) patients, respectively. Efficacy seems to be influenced by PD-L1 expression and a co-occurring KEAP1 mutation. KEAP1 was associated with an inferior survival. Other factors such as BM, STK11, and TP53 mutations had no impact on response and survival.

CONCLUSION

First results from a real-world population confirm promising efficacy of sotorasib for the treatment of advanced KRAS p.G12C-mutated NSCLC. Patients with co-occurring KEAP1 mutations seem to derive less benefit.

First-line immunotherapy for lung cancer with MET exon 14 skipping and the relevance of TP53 mutations

BACKGROUND

The efficacy of checkpoint inhibitors for non-small cell lung cancer (NSCLC) with MET exon 14 skipping (METΔ14ex) remains controversial.

MATERIALS AND METHODS

110 consecutive METΔ14ex NSCLC patients receiving first-line chemotherapy (CHT) and/or immunotherapy (IO) in 10 German centers between 2016-2022 were analyzed.

RESULTS

Combined CHT-IO was given to 35/110 (32%) patients, IO alone to 43/110 (39%), and CHT to 32/110 (29%) upfront. Compared to CHT, CHT-IO showed longer progression-free survival (median PFS 6 vs. 2.5 months, p = 0.004), more objective responses (ORR 49% vs. 28%, p = 0.086) and numerically longer overall survival (OS 16 vs. 10 months, p = 0.240). For IO monotherapy, OS (14 vs. 16 months) and duration of response (26 vs. 22 months) were comparable to those of CHT-IO. Primary progressive disease (PD) was more frequent with IO compared to CHT-IO (13/43 vs. 3/35, p = 0.018), particularly for never-smokers (p = 0.041). Higher PD-L1 TPS were not associated with better IO outcomes, but TP53 mutated tumors showed numerically improved ORR (56% vs. 32%, p = 0.088) and PFS (6 vs. 3 months, p = 0.160), as well as longer OS in multivariable analysis (HR=0.54, p = 0.034) compared to their wild-type counterparts. Any second-line treatment was administered to 35/75 (47%) patients, with longer survival for capmatinib or tepotinib compared to crizotinib (PFS 10 vs. 3 months, p = 0.013; OS 16 vs. 13 months, p = 0.270).

CONCLUSION

CHT-IO is superior to CHT, and IO alone also effective for METΔ14ex NSCLC, especially in the presence of TP53 mutations and independent of PD-L1 expression, but never-smokers are at higher risk of primary PD.

Lung Cancer Related Thrombosis (LCART): Focus on Immune Checkpoint Blockade

Cancer-associated thrombosis (CAT) is a common complication in lung cancer patients. Lung cancer confers an increased risk of thrombosis compared to other solid malignancies across all stages of the disease. Newer treatment agents, including checkpoint immunotherapy and targeted agents, may further increase the risk of CAT. Different risk-assessment models, such as the Khorana Risk Score, and newer approaches that incorporate genetic risk factors have been used in lung cancer patients to evaluate the risk of thrombosis. The management of CAT is based on the results of large prospective trials, which show similar benefits to low-molecular-weight heparins (LMWHs) and direct oral anticoagulants (DOACs) in ambulatory patients. The anticoagulation agent and duration of therapy should be personalized according to lung cancer stage and histology, the presence of driver mutations and use of antineoplastic therapy, including recent curative lung surgery, chemotherapy or immunotherapy. Treatment options should be evaluated in the context of the COVID-19 pandemic, which has been shown to impact the thrombotic risk in cancer patients. This review focuses on the epidemiology, pathophysiology, risk factors, novel predictive scores and management of CAT in patients with active lung cancer, with a focus on immune checkpoint inhibitors.

Abstract 2524: Critical interactions and tumor-specific mutations of Bcl-2 transmembrane domains revealed by a novel split luciferase assay

In intrinsic apoptosis, the interaction network of the Bcl-2 protein family controls the decision over life and death. Cells are sentenced to death when pro-apoptotic multidomain effector proteins BAX, BAK or BOK oligomerize and form pores in the mitochondrial outer membrane. This releases cytochrome c, which induces the activation of cell-wrecking proteases, the caspases. Interactions of Bcl-2 proteins with other family members essentially regulate cell death. The interaction via the BH3 region was intensively studied in the last decades. As a result, small-molecule drugs, BH3-mimetics, were developed which bind and inhibit anti-apoptotic Bcl-2 proteins. Since anti-apoptotic Bcl-2 proteins are often overexpressed in hematopoietic malignancies, BH3-mimetics e.g. Venetoclax are approved for anti-cancer therapy. Unlike the BH3 interaction site, the c-terminal α9-helix referred to as the transmembrane domain (TMD) is mostly neglected in Bcl-2 interaction studies. However, TMDs not only dictate subcellular localization, but also substantially influence protein-protein interactions. Interestingly, Bcl-2 TMDs can harbor several tumor-specific mutations. The functional basis for TMD interaction as well as the resulting functional relevance for apoptosis signaling, however, remains poorly understood. To unravel the Bcl-2 TMD interaction network, we developed a split luciferase assay system enabling us to detect Bcl-2 TMD interactions in living cells. Simultaneously encoding for the expression of a fluorophore and TMD fusion peptides this system was used to generate fluorescence-normalized luminescence-based interaction data. Here, we identified a homotypic interaction pattern among effector TMDs of BAX, BAK and BOK. Molecular modelling of effector TMD interaction in mimics of cellular membranes also supports these findings. TMD swap experiments show significant influence of TMD sequence on subcellular localization and cell death signaling as assessed via confocal laser scanning microscopy and flow cytometry-based cell death assays. Moreover, we tested previously described mutations of the BAX-TMD (S184A, S184D) as well as a tumor-specific mutation (V180G) in the novel interaction assay. S184 (de-)phosphorylation as mimicked with S184A/S184D affects subcellular localization. In accordance, we find that S184A enhanced and S184D abolished interaction with wildtype BAX-TMD. Intriguingly, V180G not only modulates BAX subcellular localization but also prevents interaction with wildtype BAX-TMD. These findings verify a crucial role of Bcl-2 TMDs in subcellular localization and furthermore strongly support a function in interaction and cell death regulation. Further efforts to explore the Bcl-2 TMD interaction network as well as functional analysis of tumor-specific TMD mutations could pave the way to establish TMDs as a target of cancer therapy.

Citation Format: Tobias B. Beigl, Alexander Paul, Sandra Weller, Benjamin Schäfer, Walter E. Aulitzky, Hans-Georg Kopp, Thomas Fellmeth, Kristyna Pluhackova, Markus Rehm, Frank Essmann. Critical interactions and tumor-specific mutations of Bcl-2 transmembrane domains revealed by a novel split luciferase assay [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2524.

Abstract 2532: Disrupting resistance to EGFR-specific tyrosine kinase inhibitors in TP53-mutated lung carcinoma cell lines by proteasome inhibition

Lung cancer is the leading cause of cancer related death. The most common form is non-small cell lung cancer (NSCLC). In a large proportion of NSCLC, driver mutations in protein kinases are found. One of the most frequently affected gene is the epidermal growth factor receptor (EGFR). Anti-cancer drugs have been developed that specifically inhibit mutated EGFR and are effective in anti-cancer therapy. However, resistance mediating mutations occur regularly during therapy limiting both treatment outcome and therapeutic options for follow up therapy. In sarcoma cell lines, resistance has already been overcome by a combination of proteasome inhibitors (PIs) with BH3 mimetics (Muenchow et al., 2020). In this case, drugs were combined that have an independent mechanism of action. In ALK-rearranged/TP53-mutated NSCLC cells, ALK-TKI resistance is also overcome by proteasome inhibition that mediates induction of the pro-apoptotic protein NOXA (Tanimoto et al., 2020). Since NOXA inhibits anti-apoptotic BCL-2 proteins, we hypothesize that combined treatment with receptor tyrosine kinase inhibitors (RTKIs) and PI or BCL-2 inhibitors (BCL2I) is an effective strategy for the treatment of EGFR mutated NSCLC tumors. To explore this hypothesis, we investigated cell death induction by combined administration of RTKI and PI in NSCLC cells differing in their mutational status, i.e., RTKI resistance. In addition, we analyzed the expression of effector BCL-2 family proteins (BAX, BAK, BOK) to determine their relevance to cell death induction and their informative value as predictive markers.

By flow cytometric analysis of apoptosis markers (exposure of phosphatidyl serine, loss of mitochondrial membrane potential) we showed that the RTKI Osimertinib and PI Bortezomib synergistically induce cell death in H1650 and HCC4006 cells, independent of RTKI resistance. Importantly, Western blot analysis showed RTKI-induced accumulation of the pro-apoptotic BH3-only protein NOXA in the HCC4006 and H1650 cancer cell lines. Additionally, the H1975 showed a similar effect combining Osimertinib and ABT-199, a BCL2I, in flow cytometric analysis and Western blot.

In summary, the presented experiments support the hypothesized synergistic cell death induction by RTK-inhibitors and proteasome inhibition as well as BCL-2-inhibition.

Studying the molecular mechanism of synergistic efficacy of RTKI/PI or RTKI/BCL2I combination therapies may form the basis for a general therapeutic concept which relies on simultaneous blocking of driver mutations and survival-promoting BCL-2 proteins.

Citation Format: Franziska Orth, Benjamin Schaefer, Annika Harsch, Sandra Weller, Tobias Beigl, Lynn Barber, Hans-Georg Kopp, Frank Essmann. Disrupting resistance to EGFR-specific tyrosine kinase inhibitors in TP53-mutated lung carcinoma cell lines by proteasome inhibition [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2532.

A post hoc analysis of the EPAZ trial: The role of geriatric variables in elderly soft tissue sarcoma patients on toxicity and outcome

OBJECTIVE

The EPAZ study (NCT01861951) showed recently that pazopanib was non-inferior to doxorubicin in patients ≥60 years treated in first line for advanced soft tissue sarcoma . The current post-hoc analysis aimed to assess the prognostic impact of frailty.

METHODS

Geriatric assessments were evaluated at baseline. Age >75 years, liposarcoma, ECOG = 2, G8 ≤14, instrumental activities of daily living (IADL) ≥1 and Charlson Comorbidity Index ≥2 were tested for their impact on progression-free survival (PFS), overall survival (OS), CTCAE grade 3/4 adverse events (AEs) or serious AEs (SAEs), using univariate and multivariate analysis models.

RESULTS

univariate analysis showed an increased risk of grade 3/4 AEs and SAEs for ECOG = 2, G8 score ≤14 or IADL ≥1, independent of treatment. The multivariate analysis exhibited for pazopanib a significantly reduced risk for grade 3/4 AEs (HR 0.53; p = 0.033), and in patients with G8 ≤14 an increased risk for SAEs (HR 2.67; p = 0.011). In the multivariate analysis, G8 ≤14 was a negative prognostic factor for PFS (HR 1.82; p = 0.009) and IADL ≥1 for OS (HR 2.02; p = 0.007). ECOG = 2 was the strongest negative predictor for PFS (HR 4.39; p = 0.001) and OS (HR 3.74; p = 0.004). Neither age nor Charlson Comorbidity Index showed any impact on PFS, OS, incidence of grade 3/4 AEs or SAEs.

CONCLUSIONS

This post hoc analysis demonstrated that age is not a denominator for outcome or toxicity in elderly patients with soft tissue sarcoma . Instead, geriatric and functional assessments should be used to counsel patients and tailor therapy to individual needs. Moreover, pazopanib has a reduced risk for grade 3/4 AEs compared to doxorubicin.

Germline findings in patients with advanced malignancies screened with paired blood-tumour testing for personalised treatment approaches

BACKGROUND

Sequencing of tumour tissue with comprehensive gene panels is increasingly used to guide treatment in precision oncology. Analysis of tumour-normal pairs allows in contrast to tumour-only assessment direct discrimination between somatic and germline alterations, which might have important implications not only for the patients but also their families.

METHODS

We performed tumour normal sequencing with a large gene panel in 1048 patients with advanced cancer to support treatment decision. Sequencing results were correlated with clinical and family data.

RESULTS

We identified 156 likely pathogenic or pathogenic (LP/P) germline variants in cancer predisposition genes (CPGs) in 144 cases (13.7%). Of all patients, 8.8% had a LP/P variant in autosomal-dominant cancer predisposition genes (AD-CPGs), most of them being genes with high or moderate penetrance (ATM, BRCA2, CHEK2 and BRCA1). In 48 cases, the P/LP variant matched the expected tumour spectrum. A second variant in tumour tissue was found in 31 patients with AD-CPG variants. Low frequency mutations in either TP53, ATM or DNMT3A in the normal sample indicated clonal haematopoiesis in five cases.

CONCLUSIONS

Tumour-normal testing for personalised treatment identifies germline LP/P variants in a relevant proportion of patients with cancer. The majority of them would not have been referred to genetic counselling based on family history. Indirect functional readouts of tumour-normal sequencing can provide novel links between CPGs and unexpected cancers. The interpretation of increasingly complex datasets in precision oncology is challenging and concepts of interdisciplinary personalised cancer prevention are needed to support patients and their families.

Abstract 3706: Double impact of ABT-199 by directly blocking anti-apoptotic BCL-2 and inhibiting MCL-1 via transactivation of NOXA

Soft-Tissue Sarcomas (STS) are mesenchymal malignancies with high heterogeneity and poor prognosis. As recently shown, ABT-199 and Bortezomib (BTZ) synergistically induce apoptosis in STS derived cells and cell lines (Muenchow et al. 2020). This is of great importance due to limited clinical therapeutic options and lower dependence on BCL-2 expression in solid cancers. To delineate the molecular basis for the synergism of ABT-199 and BTZ, we thought to elucidate the mechanism leading to enhanced expression of the BH3-only protein NOXA. We investigated whether proteasome inhibition augmented the expression of NOXA in a TP53-regulated manner. To clarify a possible role of TP53 in increased NOXA expression, we performed knock-down of TP53 and analyzed transcription of PMAIP1 by qRT-PCR and expression of NOXA protein by Western Blot in presence of ABT-199 alone and in combination with BTZ. Previous reports also show that ABT-199 impairs complex I and II activity of the electron transport chain (ETC), resulting in induction of metabolic reprogramming confirmed by enhanced reductive carboxylation (Roca-Portoles et al. 2020). The ratio of α-ketoglutarate : citrate, indicating disbalance of the ETC, was assessed by mass spectrometric analysis in SW982/WT cells after incubation with ABT-199 alone and in combination with BTZ. Moreover, we gained further insight into the molecular mechanism of action of enhanced NOXA expression by analyzing ABT-199 and BTZ induced cell death induction in time kinetics of cell death induction in knock-down experiments using CellTOX Green as indicator. We found that ABT-199 induced the expression of NOXA by a mainly TP53-independent mechanism at the transcriptional level. Indeed, our data suggest that ABT-199 induces metabolic reprogramming leading to enhanced reductive carboxylation, evidenced by an increased ratio of α-ketoglutarate : citrate. Subsequent activation of the integrated stress response (ISR) induces expression of the known ISR markers ATF3 and ATF4 at both the transcriptional and protein levels. Silencing of ATF3 and ATF4 significantly reduced NOXA expression and NOXA mediated cell death induction. Therefore, we propose that transactivation of NOXA by ABT-199 and subsequent sensitization to proteasome inhibitors effectively induces cell death in solid cancers. The double impact of ABT-199 by i) directly blocking anti-apoptotic BCL-2 and ii) inhibiting MCL-1 via transactivated NOXA is of high clinical relevance, because combined treatment with proteasome inhibitors might overcome intrinsic or acquired resistance to BH3-mimetics. Thus, the here described novel effect of ABT-199 to transactivate NOXA expression, should prompt future efforts in the clinical evaluation of combinatorial regimens in additional malignancies. We hypothesize that these effects represent generally active principles of a tumor-agnostic mechanism of action.

Citation Format: Sandra Weller, Benjamin Schaefer, Tobias B. Beigl, Kathrin Böpple, Ute Hofmann, Walter E. Aulitzky, Hans-Georg Kopp, Frank Essmann. Double impact of ABT-199 by directly blocking anti-apoptotic BCL-2 and inhibiting MCL-1 via transactivation of NOXA [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3706.

Abstract 3710: Synergistic cell death induction in ovarian cancer by cisplatin and ABT-199 is mediated by expression of NOXA

Ovarian cancer is among the top ten leading causes of cancer death in women worldwide with a mortality rate of roughly 5% among all cancer deaths. So far, there are no recommended screening tests for the early detection of ovarian cancer. Therefore, patients are frequently diagnosed at late stages of ovarian cancer, which is associated with unfavorable 5-year survival. Patients suffering from ovarian cancer often show a good response to initial therapy with platinum-based compounds and/or taxanes subsequent to resection of the affected tissue. Unfortunately, ovarian cancer shows a high frequency of relapse and after chemotherapy persistent tumor cells re-expand and successively evolve into therapy-resistant tumors.

We recently reported that cisplatin (cisPt) treatment of ovarian cancer cells enhances mitochondrial content and mitochondrial reactive oxygen species (Kleih et al. 2019). We therefore speculated that the enhanced mitochondrial content primes cisPt-treated cells for apoptosis induced by BH3 mimetic drugs, such as Venetoclax (ABT-199), that act on anti-apoptotic Bcl-2 proteins at the outer mitochondrial membrane. To explore this hypothesis, we investigated whether the combined administration of cisPt and ABT-199 leads to a synergistic cell death induction in ovarian cancer cells with different cisPt resistance and mitochondrial content.

Detection of cell death by flow cytometric measurements of the mitochondrial membrane potential and exposure of phosphatidylserine demonstrated a synergistic cell death induction by cisPt and ABT-199 in OVCAR4 and OVCAR8 cells, irrespective of the cisPt resistance. Interestingly, Western blot analysis revealed that ABT-199 induced the accumulation of the BH3-only protein NOXA in both cancer cell lines. Accumulation of NOXA was dependent on ABT-199-mediated activation of the stress-responsive transcription factor ATF4. Knock-down experiments showed that apoptosis of cisPt-resistant OVCAR8 cells by the combined treatment with ABT-199 and cisPt was entirely dependent on NOXA. Moreover, also cisPt-sensitive OVCAR4 cells revealed an initially reduced apoptosis induction by the NOXA knock-down.

Our data therefore elucidate the molecular mechanism of the synergistic efficacy of cisPt/ABT-199 combination therapies, which should be promising especially for the treatment of recurrent tumors developing reduced sensitivity to cisPt-based treatments.

Citation Format: Benjamin Schaefer, Sandra Weller, Tobias B. Beigl, Klaus Schulze-Osthoff, Hans-Georg Kopp, Walter E. Aulitzky, Frank Essmann. Synergistic cell death induction in ovarian cancer by cisplatin and ABT-199 is mediated by expression of NOXA [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3710.

Abstract 3704: The C-terminal transmembrane domain of BAX is essential for BAX auto-inhibition

Apoptosis is a complex and highly regulated cellular suicide program culminating in a caspase-dependent self-destruction. As a critical step of intrinsic apoptosis, pro-apoptotic effector Bcl-2 proteins BAX, BAK and BOK form pores in the mitochondrial outer membrane (MOM) which causes Cytochrome C release, followed by caspase-activation and ultimately cell death. In contrast to BAK and BOK, BAX mainly resides in the cytosol and translocates to mitochondria when activated by pro-apoptotic signals. During activation and translocation, BAX undergoes conformational changes including dislodging of the c-terminal α-9 helix from the hydrophobic groove and insertion in the MOM. Most studies concerning BAX activation focus on the interaction of the BH3 domain and the hydrophobic groove, which is essential for BAX inhibition by members of the Bcl-2 family. In contrast, how modifications of the α-9 transmembrane domain (TMD) can impair BAX inhibition and membrane insertion remains understudied so far, so that functional roles of the TMD in BAX activation and translocation are yet to be defined. To determine the role of the BAX-TMD in activation and translocation, we generated several plasmids encoding for BAX chimeras in which the original BAX-TMD sequence was swapped for TMDs of other Bcl-2 proteins. The chimeric BAX proteins were expressed in human cell lines and cell death as well as protein localisation was investigated. Surprisingly, we found that swapping the BAX-TMD for another effector TMD increases BAX pro-apoptotic activity assessed via Annexin-V staining and flow cytometry. In addition, confocal microscopy revealed that BAX shows an increased tendency to mitochondrial localisation and oligomerisation when bearing TMDs of BAK or BOK. Interestingly, co-expressed anti-apoptotic BCL-2 an antagonistic binding-partner of BAX co-localises with BAX chimeras but poorly prevents cell death induced by the BAX chimera with the BAK-TMD. These findings strongly support a crucial regulatory role of the BAX-TMD in activation and translocation. In fact, the increased apoptotic potential of the BAX-TMD chimeras as well as augmented mitochondrial localisation suggest an auto-inhibitory function of the BAX-TMD ensured by its affinity to the BAX hydrophobic groove. Moreover, the decreased inhibitory capacity of Bcl-2 for the BAK-TMD-containing BAX chimera could point to an involvement of the BAX-TMD in interaction with BCL-2. In contrast to the archetypical understanding of the TMD as a mere membrane anchor, these results also indicate that the TMD can regulate the activity of BAX and other Bcl-2 family proteins.

Citation Format: Tobias Benjamin Beigl, Sandra Weller, Benjamin Schäfer, Walter Erich Aulitzky, Hans-Georg Kopp, Markus Rehm, Frank Essmann. The C-terminal transmembrane domain of BAX is essential for BAX auto-inhibition [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3704.

Perioperative ramucirumab in combination with FLOT versus FLOT alone for resectable esophagogastric adenocarcinoma (RAMSES/FLOT7) with high rate of signet cell component: Final results of the multicenter, randomized phase II/III trial of the German AIO and Italian GOIM

4042

Background: Periop. FLOT has become SOC for resectable, esophagogastric adenocarcinoma. However, patient’s outcome is still poor. This trial evaluates the addition of the VEGF-R2 inhibitor ramucirumab (RAM) to FLOT for resectable patients (pts). Methods: This is a prospective, international, randomized, investigator-initiated phase II/III trial. Pts with resectable, Her2-negative, adenocarcinoma of the stomach and GEJ type II and III (≥ cT2 or cN+) were enrolled. Pts were randomized to 4 pre-and post-operative cycles of FLOT (docetaxel 50 mg/m²; oxaliplatin 85 mg/m²; leucovorin 200 mg/m²; 5-FU 2600 mg/m², q2w) alone (Arm A) or the same regimen with RAM 8mg/kg q2w, followed by 16 cycles RAM (Arm B, FLOT-RAM). Important endpoints of phase II (exploratory) were major pathological (complete and nearly complete) response, centrally assessed acc. to Becker criteria, R0-resection rate, overall survival (OS), disease-free survival (DFS) and safety. GEJ type I tumors and pts requiring trans-thoracic esophagectomy were excluded for safety reasons during the conduct of the study. Results: In total, 152 pts were analyzed within the intention to treat population. Baseline characteristics were similar between arms (male, 70%; median age, 60y; cT3/T4, 82%; cN+, 77%; GEJ, 45%). The rate of cancers with signet-ring cell component was at 45%. The FLOT-RAM arm included more unfavorable pts with T4 (8% vs. 5%), impaired ECOG PS of 1 (32% vs. 20%), and concomitant disease (86% vs. 76%). 92% of pts with FLOT as well as with FLOT-RAM completed the 4 pre- cycles. R0-resection could be achieved in 82% of pts with FLOT and 96% of pts with FLOT-RAM (p = 0.0093). The rate of major path response was similar in both arms and was 29% for FLOT and 26% for FLOT-RAM. Median DFS was slightly improved in pts with FLOT-RAM (32 months vs. 21 months), while median OS was similar in both treatment arms (FLOT 45 months, FLOT-RAM 46 months). Surgical morbidity was observed in 32% of pts with FLOT and 41% of pts with FLOT-RAM. Mortality at 60 days after surgery was 4.1% with FLOT and 2.8% with FLOT-RAM. There were bit more G≥3 adverse events with FLOT-RAM (76% vs. 92%). Conclusions: In this phase II trial, the addition of ramucirumab to perioperative FLOT significantly improved R0-resection rates and slightly prolonged DFS without an impact on path response or overall survival. FLOT-RAM is feasible and safe, when type I tumors are excluded. Clinical trial information: NCT02661971.

PTEN mutant non-small cell lung cancer require ATM to suppress pro-apoptotic signalling and evade radiotherapy

Background

Despite advances in treatment of patients with non-small cell lung cancer, carriers of certain genetic alterations are prone to failure. One such factor frequently mutated, is the tumor suppressor PTEN. These tumors are supposed to be more resistant to radiation, chemo- and immunotherapy.

Results

We demonstrate that loss of PTEN led to altered expression of transcriptional programs which directly regulate therapy resistance, resulting in establishment of radiation resistance. While PTEN-deficient tumor cells were not dependent on DNA-PK for IR resistance nor activated ATR during IR, they showed a significant dependence for the DNA damage kinase ATM. Pharmacologic inhibition of ATM, via KU-60019 and AZD1390 at non-toxic doses, restored and even synergized with IR in PTEN-deficient human and murine NSCLC cells as well in a multicellular organotypic ex vivo tumor model.

Conclusion

PTEN tumors are addicted to ATM to detect and repair radiation induced DNA damage. This creates an exploitable bottleneck. At least in cellulo and ex vivo we show that low concentration of ATM inhibitor is able to synergise with IR to treat PTEN-deficient tumors in genetically well-defined IR resistant lung cancer models.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13578-022-00778-7.

Outcomes With Pembrolizumab Plus Platinum-Based Chemotherapy for Patients With Non-Small-Cell Lung Cancer and Stable Brain Metastases: Pooled Analysis of KEYNOTE-021, 189, and 407

INTRODUCTION

This exploratory analysis retrospectively evaluated outcomes in patients with advanced NSCLC to determine whether baseline brain metastases influenced the efficacy of first-line pembrolizumab plus chemotherapy versus chemotherapy alone.

PATIENTS AND METHODS

We pooled data for patients with advanced NSCLC in KEYNOTE-021 cohort G (nonsquamous), KEYNOTE-189 (nonsquamous), and KEYNOTE-407 (squamous). Patients were assigned to platinum-doublet chemotherapy with or without the addition of 35 cycles of pembrolizumab 200 mg every 3 weeks. All studies permitted enrollment of patients with previously treated or untreated (KEYNOTE-189/KEYNOTE-407 only) stable brain metastases. Patients with previously treated brain metastases were clinically stable for ≥2 weeks (≥4 weeks in KEYNOTE-021 cohort G), had no evidence of new or enlarging brain metastases, and had no steroid use ≥3 days before dosing. Patients with known untreated asymptomatic brain metastases required regular imaging of the brain.

RESULTS

1298 patients were included, 171 with and 1127 without baseline brain metastases. Median (range) durations of follow-up at data cutoff were 10.9 (0.1‒35.1) and 11.0 (0.1‒34.9) months, respectively. Hazard ratios (pembrolizumab plus chemotherapy/chemotherapy) were similar for patients with and without brain metastases for overall survival (0.48 [95% CI, 0.32‒0.70] and 0.63 [95% CI, 0.53‒0.75], respectively) and progression-free survival (0.44 [95% CI, 0.31‒0.62] and 0.55 [95% CI, 0.48‒0.63], respectively). In patients with brain metastases, median overall survival was 18.8 months with pembrolizumab plus chemotherapy and 7.6 months with chemotherapy, and median progression-free survival was 6.9 months and 4.1 months, respectively. Objective response rates were higher and duration of response longer with pembrolizumab plus chemotherapy versus chemotherapy regardless of brain metastasis status. Incidences of treatment-related adverse events with pembrolizumab plus chemotherapy versus chemotherapy were 88.2% versus 82.8% among patients with brain metastases and 94.5% versus 90.6% in those without.

CONCLUSION

With or without brain metastasis, pembrolizumab plus platinum-based histology-specific chemotherapy improved clinical outcomes versus chemotherapy alone across all PD-L1 subgroups, including patients with PD-L1 tumor proportion score <1%, and had a manageable safety profile in patients with advanced NSCLC. This regimen is a standard-of-care treatment option for treatment-naïve patients with advanced NSCLC, including patients with stable brain metastases.

Abstract 1946: Synergistic cell death induction in breast cancer cell lines by combining ABT-199 and cisplatin irrespective of estrogen receptor and p53 expression

50 Years after the generation of the most studied human breast cancer cell line, MCF-7, many research results fundamentally changed patient outcomes for the better. The mortality of breast cancer in women has decreased significantly, especially in the last 30 years. But the total number of deaths is rising again in the last ten years. Considering that breast cancer is the most common cancer in women and the second most common cancer overall, with incidences of 24,2% and 11,6%, respectively, total numbers of new cases are in the millions every year.

First line drugs for the treatment of breast cancer often target microtubules (e.g. Vinblastine and Paclitaxel) or induce DNA damage (e.g. Carboplatin and Cisplatin (CisPt)). In addition to these classic therapeutic drugs new compounds that specifically target cancer-driving molecular alterations have been developed. Among these is the group of BH3-mimetics. The efficacy of several BH3-mimetics is investigated in numerous clinical trials while the BCL-2 specific inhibitor ABT-199 (Venetoclax) is already approved for clinical application in chronic lymphatic leukemia (CLL), acute myeloid leukemia (AML) and small lymphocytic lymphoma (SLL). BH3-mimetics target the apoptosis machinery by interacting with anti-apoptotic Bcl-2 proteins, mimicking the function of pro-apoptotic BH3-only proteins. In turn, the pro-apoptotic potential of pore-forming BCL-2 effectors BAX, BAK and BOK is released inducing mitochondrial outer membrane permeabilization and cell death.

Recently we reported synergistic cell death induction by ABT-199 in combination with the proteasome inhibitor Bortezomib (BOZ) in soft tissue sarcoma (STS) cells. ABT-199 and BOZ induce accumulation of BOK and the BH3-only protein NOXA (Muenchow et al. 2020). Here, we combined ABT-199, CisPt and Nutlin-3 in breast cancer cell lines that differ in expression of the estrogen receptor (ER) and p53 activity. Similar to the results in STS cells synergistic induction of apoptotic cell death was observed by FACS analysis of the mitochondrial membrane potential (TMRM) and exposure of phosphatidyl serine (Annexin-V). Western blot analysis revealed that ABT-199 induced accumulation of NOXA and MCL-1, irrespective of the ER status or p53 mutation. Simultaneous treatment with ABT-199 and CisPt or Nutlin-3 further increased expression of NOXA and MCL-1. Interestingly, qRT-PCR revealed enhanced expression of NOXA and MCL-1 mRNA in ABT-199 treated cells indicating transcriptional regulation. However, transcriptional induction of NOXA was also detected independent of p53 activity. Thus, combined therapeutic approaches using CisPt and ABT-199 should be effective irrespective of ER and p53 expression. Nevertheless, in p53 proficient tumors Nutlins might increase therapeutic efficacy.

Citation Format: Benjamin Schaefer, Sandra Weller, Tobias Beigl, Kathrin Boepple, Reiner Hoppe, Klaus Schulze-Osthoff, Hans-Georg Kopp, Walter E. Aulitzky, Frank Essmann. Synergistic cell death induction in breast cancer cell lines by combining ABT-199 and cisplatin irrespective of estrogen receptor and p53 expression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1946.

Abstract 325: Nascent proteome analysis of tumor cells and their microenvironment in cultured human tumor tissues

Solid tumors are often considered as abnormal organs composed of the cancerous cells and their surrounding tumor microenvironment (TME) containing fibroblasts, immune cells, blood and lymphatic vessels, and the extracellular matrix. The heterotypic interactions between this diversity of cell types within the TME are maintained through a wide variety of secreted proteins, resulting in a favorable milieu for the progression of the malignancy. The interactions between tumor cells and TME are complex and remain poorly understood. Here we investigated this by developing a unique nascent proteomic approach in tumor tissues.Precision cut cancer tissue slices (PCCTS) maintain tissue heterogeneity with different cell types and preserved TME. Cultivation of PCCTS provides an ex vivo model for tumor tissues. We developed an approach for PCCTS's nascent proteome analysis, using pulsed-SILAC (stable isotope labeling with amino acids in cell culture) labeling combined with click-chemistry to selectively isolate and quantify newly synthesized proteins in the TME upon applying a cellular perturbation. It is a powerful tool to selectively enrich secretory proteins from culture media even with presence of serum. Primary human ovarian tumors (phOVT) and patient derived xenografts (PDX) were used to produce the PCCTS with thickness of 150µm to 300µm. The different cell types and extracellular matrix of PCCTS make the depletion period of cells from the amino acids (methionine, lysine and arginine) prior the AHA-SILAC treatment difficult to define. The PCCTS need longer depletion periods than the 2D cell culture, the longer the depletion period the better depletion efficiency. Following, PCCTS were cultured in AHA-SILAC media and treated with cisplatin. PCCTS and culture media (containing secreted proteins) were harvested; newly synthesized proteins were enriched via click-chemistry and analyzed with mass spectrometry. The labeling time of 10 to 12h showed a good labeling efficiency of more than 60%, still further optimizations are needed. Different PCCTS showed various labeling efficiency indicating the patients heterogeneity. The nascent proteome analysis with cisplatin treatment demonstrated different protein regulations in patients suggesting different drug responses. STRING analysis can be applied to predict the protein-protein interactions. The immunohistochemical staining of the same PCCTS can be processed to further validate the results of the proteome analysis. In conclusion, we established a pulsed SILAC-AHA treatment approach for the PCCTS with the TME. This unique approach allows tracking the compositional and dynamic changes within the proteome and monitoring the direct proteome response at rapid time scale. It can be used to reveal a part of the proteome that has been poorly understood in the tumor tissues and contribute to studying cellular communication and finding new therapeutic targets.

Citation Format: Meng Dong, Karim Aljakouch, Kathrin Böpple, Bernd Winkler, Julia Schüler, Frank Essmann, Hans-Georg Kopp, Jeroen Krijgsveld, Walter E. Aulitzky. Nascent proteome analysis of tumor cells and their microenvironment in cultured human tumor tissues [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 325.

Abstract 1398: Impact of proteasome inhibitor specificity and efficacy on apoptosis induction by combination with ABT-199

Metastatic Soft-Tissue Sarcomas (STS) are a rare and highly heterogeneous group of mesenchymal malignancies that carry a poor prognosis. Therapy is hampered by a limited number of effective treatments, and the almost non-existing long-term survival rate illustrates the need of effective targeted treatment. As a potential approach, we investigated combination of the clinically approved BH3-mimetic drug ABT-199 with different proteasome inhibitors (PIs): Bortezomib, Carfilzomib and Ixazomib, each with proven efficacy, e.g., in multiple myeloma. ABT-199 selectively inhibits the anti-apoptotic protein Bcl-2 while Bortezomib (BOZ) and Ixazomib (IXZ) bind reversible to the β1 and β5 subunits of the 20S proteasome and Carfilzomib (CFZ) irreversibly blocks the subunits β2 and β5. We investigated whether the combination of ABT-199 with CFZ or IXZ shows synergistic activity as recently published for BOZ. SW982 sarcoma cells were cultured with PIs alone or in combination with ABT-199. Cell death was detected by flow cytometric analysis of mitochondrial membrane potential (TMRM) and exposure of phosphatidyl serine (Annexin V). To elucidate potential differences due to specificity of PIs, we analyzed expression of BCL-2 family proteins by Western Blot and performed analogue experiments in knock-out (BAXKO, BAKKO, BOKKO) cell lines. In combination, ABT-199&BOZ or ABT-199&CFZ showed comparable synergistic cell death induction in SW982 while ABT-199&IXZ less efficiently induced cell death. Engineered SW982 knock-out cell lines suggests specific relevance of BOK in IXZ induced apoptosis, whereas all tested PIs crucially depend on BAX for apoptosis induction in combination with ABT-199. Also, as shown for ABT-199&BOZ, both CFZ and IXZ, alone and in combination with ABT-199, efficiently induced expression of NOXA. Strikingly, and in line with augmented cell death induction, ABT-199&CFZ resulted in highest expression of NOXA as compared to BOZ and IXZ. ABT-199&PIs synergistically induce apoptotic cell death in SW982 and corresponding knock-out cell lines with CFZ showing exacerbated expression of NOXA. ABT-199&CFZ also induced strongest stabilization of p53, a transcriptional key regulator of NOXA. We suggest that simultaneous inhibition of anti-apoptotic BCL-2 by ABT-199 and the enhanced expression of NOXA double-hit on the BCL-2 and the MCL-1 signaling axis force the cells over the threshold of apoptosis. Enhanced efficacy of CFZ is dually caused by reduced degradation of NOXA and enhanced stabilization of p53, which in turn transactivates expression of NOXA. In conclusion, PI specificity and efficacy modulate apoptosis induction by combination with ABT-199. Future efforts, e.g. knock-out of relevant BH3-only proteins, will elucidate the observed variable efficacy of these and other PIs for prospective translation in clinical applications.

Citation Format: Sandra Weller, Benjamin Schaefer, Tobias Beigl, Kathrin Böpple, Walter E. Aulitzky, Hans-Georg Kopp, Frank Essmann. Impact of proteasome inhibitor specificity and efficacy on apoptosis induction by combination with ABT-199 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1398.

Bispecific NKG2D-CD3 and NKG2D-CD16 Fusion Proteins as Novel Treatment Option in Advanced Soft Tissue Sarcomas

Soft tissue sarcoma (STS) constitutes a rare group of heterogeneous malignancies. Effective treatment options for most subtypes of STS are still limited. As a result, especially in metastatic disease, prognosis is still dismal. The ligands for the activating immunoreceptor NKG2D (NKG2DL) are commonly expressed in STS, but generally absent in healthy tissues. This provides the rationale for utilization of NKG2DL as targets for immunotherapeutic approaches. We here report on the preclinical characterization of bispecific fusion proteins (BFP) consisting of the extracellular domain of the NKG2D receptor fused to Fab-fragments directed against CD3 (NKG2D-CD3) or CD16 (NKG2D-CD16) for treatment of STS. After characterization of NKG2DL expression patterns on various STS cell lines, we demonstrated that both NKG2D-CD16 and NKG2D-CD3 induce profound T and NK cell reactivity as revealed by analysis of activation, degranulation and secretion of IFNγ as well as granule associated proteins, resulting in potent target cell lysis. In addition, the stimulatory capacity of the constructs to induce T and NK cell activation was analyzed in heavily pretreated STS patients and found to be comparable to healthy donors. Our results emphasize the potential of NKG2D-CD3 and NKG2D-CD16 BFP to target STS even in an advanced disease.

A randomized, multicenter phase II study comparing efficacy, safety and tolerability of two dosing regimens of cisplatin and pemetrexed in patients with advanced or metastatic non-small-cell lung cancer

Background:

Pemetrexed and cisplatin is a first-line standard in non-squamous non-small-cell lung cancer without targetable mutations. It became the backbone of checkpoint-inhibitor–chemotherapy combinations. Single high doses of cisplatin pose toxicity risks and require hyperhydration, potentially prolonging outpatient application. The aim of this study was to compare efficacy, safety and tolerability of split-dose cisplatin with the standard schedule.

Methods:

Patients with metastatic non-squamous non-small-cell lung cancer were randomly assigned to up to six 21-day cycles of pemetrexed 500 mg/m² and cisplatin 75 mg/m² on day 1 (arm A), or pemetrexed 500 mg/m² (day 1) and cisplatin 40 mg/m² (day 1 + 8, arm B), followed by pemetrexed maintenance. Primary endpoint was objective response rate. Secondary objectives were overall survival, progression-free survival, time to progression, treatment compliance, toxicity profile, and quality of life.

Results:

We enrolled 130 patients (129 evaluable). Median cycle numbers in A and B were six (1–6) and five (1–6). Dose intensities were comparable between arms. More patients in A received pemetrexed maintenance (24.2% versus 11.1%). With 16 (24.2%) in A and 19 (30.2%) patients in B achieving objective responses [odds ratio 0.74 (0.34–1.62), p = 0.55] the primary endpoint was met. Overall survival was not different between arms (median 14.4 versus 14.9 months); [HR = 1.07; (0.68–1.68), p = 0.78]. Median progression-free survival was 7.0 months in A and 6.2 months in B [HR = 1.63; (1.17–2.38); p = 0.01]. Adverse events of CTCAE grade ⩾3, particularly hematological, were more frequent in B. No difference in grade 4 and 5 infections between arms was noted. Treatment-related asthenia and nausea/vomiting of any grade were more frequent in A. Global health status, fatigue and constipation measured on day 1 of cycle 4 demonstrated superior scores in B.

Conclusion:

Pemetrexed and split-dose cisplatin is safe and effective. Advantages of split-dose cisplatin with regard to specific toxicities allow personalization of this important chemotherapy backbone.

Trial Registration:

European Clinical Trials Database (EudraCT) number 2011-001963-37.

The wolf in sheep's clothing: Platelet-derived "pseudo self" impairs cancer cell "missing self" recognition by NK cells

Metastasis is strongly inhibited in thrombocytopenic mice. This phenotype is reversed by NK cell depletion which indicates that platelets may facilitate tumor progression and metastasis by interfering with NK cell immunosurveillance. Understanding the underlying mechanisms may help us to reinforce anti-tumor immunity and NK-based immunotherapy in cancer patients.

Efficacy of Pazopanib With or Without Gemcitabine in Patients With Anthracycline- and/or Ifosfamide-Refractory Soft Tissue Sarcoma: Final Results of the PAPAGEMO Phase 2 Randomized Clinical Trial

Importance

Pazopanib and gemcitabine have shown good tolerability, albeit modest single-agent activity in pretreated soft tissue sarcoma. A combined regimen to improve outcomes is required.

Objective

To determine the efficacy of gemcitabine and pazopanib compared with pazopanib alone.

Design, Setting, and Participants

This multicenter, randomized phase 2 clinical trial was conducted in Germany from September 2011 to July 2014 and included patients with an Eastern Cooperative Oncology Group performance status score of 0 to 2, adequate organ function, measurable lesion, and progression after at least 1 prior treatment with anthracyclines and/or ifosfamide. Data analysis was performed during 2019 and 2020.

Interventions

Patients were randomized to pazopanib with gemcitabine (A) or without gemcitabine (B).

Main Outcomes and Measures

The primary end point was progression-free survival rate (PFSR) at 12 weeks; secondary end points included toxicity, quality of life, overall survival, and response rates.

Results

A total of 90 patients were randomized, and 86 eligible patients (43 women [50%]) were evaluable, with a median age of 57 (range, 22-84) years and Eastern Cooperative Oncology Group performance status score of 0/1 in 77 participants (90%). The predominant histological subtypes were leiomyosarcoma (22 [26%]) and liposarcoma (16 [19%]). After a median follow-up of 12.4 (range, 1-48) months, the primary end point was met, with a PFSR at 12 weeks of 74% (A) vs 47% (B) (hazard ratio [HR], 1.60; 90% CI, 1.15-2.23; P = .01). In the combination arm, PFSR was significantly longer, with a median of 5.6 vs 2.0 months (HR, 0.58; 95% CI, 0.36-0.92; P = .02) compared with single-agent pazopanib, whereas overall survival was similar, with 13.1 vs 11.2 months (HR, 0.98; 95% CI, 0.60-1.58; P = .83). The objective response rate was overall low, with 11% (A) vs 5% (B) (P = .10). The toxicity of the combination of pazopanib and gemcitabine was increased, but it was manageable and mainly hematological.

Conclusions and Relevance

This phase 2 randomized clinical trial of patients with soft tissue sarcoma found that the addition of gemcitabine to pazopanib was tolerable, and PFSR at 12 weeks was significantly higher compared with pazopanib alone. These results suggest clinical activity of the combination, but they should be confirmed in a phase 3 trial in a more homogeneous population (eg, leiomyosarcoma).

Trial Registration

German Clinical Trials Identifier: DRKS00003139.

Randomized Comparison of Pazopanib and Doxorubicin as First-Line Treatment in Patients With Metastatic Soft Tissue Sarcoma Age 60 Years or Older: Results of a German Intergroup Study

PURPOSE

Doxorubicin is a standard of care in patients with advanced, inoperable soft tissue sarcoma (STS). We tested whether pazopanib has efficacy comparable to that of doxorubicin in elderly patients with STS and offers superior tolerability for hematologic toxicity.

PATIENTS AND METHODS

Patients age 60 years or older without previous systemic treatment for progressive advanced or metastatic STS who had Eastern Cooperative Oncology Group performance status of 0 to 2 and adequate organ function were included. Treatment consisted of pazopanib 800 mg once per day or doxorubicin 75 mg/m2 once every 3 weeks (≤ 6 cycles) after being randomly assigned in a 2:1 ratio. Noninferiority was assumed for progression-free survival (PFS), if the upper limit of the 95% CI for the hazard ratio (HR) was less than 1.8. Neutropenia and febrile neutropenia were key secondary end points. The European Organisation for Research and Treatment of Cancer (30-item) Quality of Life Questionnaire and geriatric assessment were used to measure patient-reported outcomes. Cox regression analysis and Kaplan-Meier curves were used for analysis.

RESULTS

Pazopanib and doxorubicin were given to 81 and 39 patients, respectively. The median age was 71 years (range, 60-88 years). PFS was noninferior (HR, 1.00; 95% CI, 0.65 to 1.53) and the incidence of grade 4 neutropenia and febrile neutropenia favored pazopanib. Objective response rates for pazopanib and doxorubicin were 12.3% and 15.4%, respectively. Overall survival did not differ significantly between arms (HR, 1.08; 95% CI, 0.68 to 1.72; P = .735). Geriatric assessment revealed 2 or more comorbidities in 15.8% of the patients and impairment of activities of daily living in 28.3% of patients.

CONCLUSION

Pazopanib was noninferior to doxorubicin, rendering pazopanib a putative therapeutic option in the first-line treatment of STS in patients age 60 years or older. The distinct adverse event profile may be used to counsel patients and tailor therapy to individual needs.

Hepatic toxicity during regorafenib treatment in patients with metastatic gastrointestinal stromal tumors

Regorafenib is a multi-target tyrosine kinase inhibitor that has been approved for the treatment of metastatic colorectal cancer, advanced hepatocellular carcinoma, and metastatic gastrointestinal stromal tumors (GIST). Severe hepatobiliary toxicity has been reported in patients with colorectal cancer treated with regorafenib, but not in those with GIST. Therefore, the aim of the present study was to investigate the incidence and clinical course of regorafenib-associated hepatic toxicity (HT) in patients with GIST in a real-world setting. Patients with metastatic GIST treated with regorafenib between September 2012 and May 2014 at three German tertiary care centers were followed up until August 2017. Patient records were retrospectively analyzed and descriptive statistics were employed. HT was defined as alterations in the serum values of aspartate aminotransferase, alanine aminotransferase, γ-glutamyltransferase, alkaline phosphatase and bilirubin (according to the Common Terminology Criteria for Adverse Events, version 4.0), and/or corresponding clinical signs. The time to clinical progression and the overall survival were calculated by Kaplan-Meier curves. Overall, 21 patients were treated with regorafenib and 5 (23.5%) of those heavily pretreated patients suffered from severe HT during regorafenib treatment. In 4 (80%) of these cases, regorafenib treatment was continued, optimizing individual treatment benefit. Clinical monitoring and adequate therapy management are crucial for ensuring continuation of regorafenib treatment in order to achieve an optimal clinical outcome.

C-Cbl regulates c-MPL receptor trafficking and its internalization

Thrombocyte formation from megakaryocyte and their progenitor cells is tightly regulated by thrombopoietin (TPO) and its receptor c‐MPL, thereby maintaining physiological functionality and numbers of circulating platelets. In patients, dysfunction of this regulation could cause thrombocytopenia or myeloproliferative syndromes. Since regulation of this pathway is still not completely understood, we investigated the role of the ubiquitin ligase c‐Cbl which was previously shown to negatively regulated c‐MPL signalling. We developed a new conditional mouse model using c‐Cbl^fl/flPf4^Cre mice and demonstrated that platelet‐specific knockout of c‐Cbl led to severe microthrombocytosis and impaired uptake of TPO and c‐MPL receptor internalization. Furthermore, we characterized a constitutive STAT5 activation c‐Cbl KO platelets. This study identified c‐Cbl as a potential player in causing megakaryocytic and thrombocytic disorders.

Genetic Loss of LCK Kinase Leads to Acceleration of Chronic Lymphocytic Leukemia

Most patients with chronic lymphocytic leukemia (CLL) exhibit an indolent disease course and unresponsive B cell receptors (BCRs) exemplified by an anergic phenotype of their leukemic cells. In up to 5% of patients, CLL transforms from an indolent subtype to an aggressive form of B cell lymphoma (Richter's syndrome), which is associated with worse disease outcome and severe downregulation of NFAT2. Here we show that ablation of the tyrosine kinase LCK, which has previously been characterized as a main NFAT2 target gene in CLL, leads to loss of the anergic phenotype, thereby restoring BCR signaling, which results in an acceleration of CLL. Our study identifies LCK as a main player in mediating BCR unresponsiveness and its role as a crucial regulator of anergy in CLL.

Quality of life and added value of a tailored palliative care intervention in patients with soft tissue sarcoma undergoing treatment with trabectedin: a multicentre, cluster-randomised trial within the German Interdisciplinary Sarcoma Group (GISG)

OBJECTIVES

The choice of drug treatment in advanced soft tissue sarcoma (STS) continues to be a challenge regarding efficacy, quality of life (QoL) and toxicity. Unlike other cancer types, where integrating patient-reported outcomes (PRO) has proven to be beneficial for QoL, there is no such evidence in patients with STS as of now. The YonLife trial aimed to explore the effect of a tailored multistep intervention on QoL, symptoms and survival in patients with advanced STS undergoing treatment with trabectedin as well as identifying predictors of QoL.

DESIGN

YonLife is a cluster-randomised, open-label, proof-of-concept study. The intervention incorporates electronic PRO assessment, a case vignette and expert-consented treatment recommendations.

PARTICIPANTS

Six hospitals were randomised to the control arm (CA) or interventional arm (IA). Seventy-nine patients were included of whom 40 were analysed as per-protocol analysis set.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary end point was the change of Functional Assessment for Cancer Therapy (FACT-G) total score after 9 weeks. Secondary outcomes included QoL (FACT-G subscales), anorexia and cachexia (Functional Assessment of Anorexia/Cachexia Therapy (FAACT)), symptoms (MD Anderson Symptom Inventory (MDASI)), anxiety and depression (HADS), pain intensity and interference (Brief Pain Inventory (BPI)) and survival assessment.

RESULTS

After 9 weeks of treatment, QoL declined less in the IA (ΔFACT-G total score: -2.4, 95% CI: -9.2 to 4.5) as compared with CA (ΔFACT-G total score: -3.9; 95% CI:-11.3 to 3.5; p=0.765). In almost all FACT-G subscales, average declines were lower in IA, but without reaching statistical significance. Smaller adverse trends between arms were observed for MDASI, FAACT, HADS and BPI scales. These trends failed to reach statistical significance. Overall mean survival was longer in IA (648 days) than in CA (389 days, p=0.110). QoL was predicted by symptom severity, symptom interference, depression and anxiety.

CONCLUSION

Our data suggest a potentially favourable effect of an electronic patient-reported outcomes based intervention on QoL that needs to be reappraised in confirmatory studies.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov Identifier (NCT02204111).

Abstract 4320: Ovarian cancer persister cells are characterized by enhanced ER stress gene expression correlating with poor survival

75% of women suffering from ovarian cancer are diagnosed at late stage of the disease often associated with cancer cell infiltration into the peritoneal cavity. Standard therapy is tumor resection and subsequent platin-based chemotherapy. Relapse is frequently observed caused by persisting cancer cells. Persister cells comprise a therapy-tolerant subpopulation of cancer cells and repeated therapies presumably select for increased tolerance. The present project aims to find molecular markers for the identification and targeted eradication of persister ovarian cancer cells.

Persister cells of the cisplatin-sensitive high-grade serous ovarian cancer cell line, OVCAR-3, were selected after cisplatin incubation with clinically relevant doses. Individual clones were isolated from control or cisplatin challenged OVCAR-3 cells. A subpopulation of the resulting clonal persister cells showed a distinct morphological phenotype characterized by increased migration and high viability in short- and long-term survival after cisplatin treatment. A significant upregulation (p&lt;0.001) of the endoplasmic reticulum (ER) stress marker, ATF3, was identified by RNA sequencing and this ER stress phenotype is maintained for more than 20 passages.

Additionally, the ovarian cancer OVCAR-8 luciferase reporter cell line was transduced with the “Watermelon” (WM) library [1]. The WM library is a complex barcode library that enables simultaneous tracing of cell lineage and the cellular transcriptional and proliferative states. To study cancer relapse in a CDX model, WM-labelled OVCAR-8-Luc cells were injected into mice and pulse-treated with carboplatin. Single cell RNA sequencing of 900 cells isolated from solid metastases, ascites and treatment-naïve mice revealed an increase in multiple ER stress markers including ATF3, ATF4, JUN and XBP1 in the most abundant solid relapse lineages.

Furthermore, analysis of clinical data from GEO, EGA and TCGA showed that low ATF3 expression is associated with increased 5-year-survival of patients with high-grade serous ovarian cancer (Logrank p=6.3e-6).

We found that increased ER stress correlates with survival of cancer persister cells and incidence of metastases. This phenomenon was observed in cell lines, a CDX model and clinical data from human ovarian cancer samples. We propose ER stress response, exemplified by ATF3, as a molecular marker to identify and therapeutic targeting of ovarian cancer persister cells.

[1] Metabolic switching underlies the ability of cancer persister cells to cycle under drug treatment, Oren Y et al., unpublished

Citation Format: Kathrin Böpple, Meng Dong, Markus Kleih, Andrea Gaißler, Yaara Oren, Whitney S. Henry, Moshe Oren, Yael Aylon, Bernd Winkler, Aviv Regev, Robert A. Weinberg, Hans-Georg Kopp, Walter E. Aulitzky, Frank Essmann. Ovarian cancer persister cells are characterized by enhanced ER stress gene expression correlating with poor survival [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 4320.

Abstract 5085: A preclinical model using perfusion air culture of tumor tissue slices for personalized medicine

For personalized medicine it is crucial that a preclinical model captures the complex tumor biology in vitro in order to individually predict in vivo therapy of tumors. Precision-cut tumor slices maintain tissue heterogeneity with regard to different cell types and preserved native microenvironment. To enable the use of tumor slices as preclinical model that fulfills these criteria we developed a perfusion air culture (PAC) system with continuous and precisely controlled oxygen, medium and drug supply. In the PAC system, precision-cut tumor slices are kept in-between two organotypic supports fixed in a special chamber and placed inside of a 50 mL tube with air exchange capacity housed in a standard CO2-incubator.

To evaluate the PAC system, cultured tumor slices from mouse xenografts (MCF7, H1437) and primary human ovarian tumors (phOVT) were compared to in vivo source tissues using immunohistochemistry for morphology, proliferation, DNA damage, apoptosis, and transcriptional biomarkers for cellular stress response. Results show that viability and morphology of the tumor slices are preserved for more than 7 days in the PAC system. We also compared the PAC system with the commonly used static Millipore filter (MF) system which cultures slices on a filter support at an air-liquid interface and gives rise to intra-slice gradients. Both, mouse xenografts and 9 of 15 phOVT tissue slices showed a gradient of cell proliferation and biomarker expression in the MF system while no gradient was detected in slices cultured in the PAC system. Analysis of the culture media revealed lower glucose consumption and lactate production in the PAC system as compared to the MF system indicating more efficient oxygen supply.

To analyze therapy response, Cisplatin was applied to phOVT tumor slices for 3 days. Cisplatin treatment was accompanied by minor increase of γ-H2AX in both MF and PAC systems while only in the PAC system strongly enhanced cleavage of caspase-3 was observed, indicating that the PAC system is suitable to assess functional response to drug treatment. To test whether the PAC system is also suitable for the detection of immune response in tumor slices, we analyzed the immune cells of tissue slices before and after cultivation. The patient specific immune cells and their composition is preserved throughout the culture period in the PAC system.

In conclusion, cultivation of tumor tissue slices in the PAC system provides an ex vivo model that preserves tumor heterogeneity and native microenvironment. Because the PAC system facilitates homogenous and precisely controlled supply of oxygen, nutrients and drugs, it allows long-term culture of tumor tissue and analysis of therapy response - including immune therapy. We conclude that the newly developed PAC system is suitable to perform patient specific ex vivo tests and thus allows personalized therapy adaption.

Citation Format: Meng Dong, Kathrin Böpple, Bernd Winkler, Markus Kleih, Julia Schüler, Emma Davies, Tauno Metsalu, Heike Walles, Hans-Georg Kopp, Frank Essmann, Walter E. Aulitzky. A preclinical model using perfusion air culture of tumor tissue slices for personalized medicine [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5085.

Abstract 6227: ABT-199 and Bortezomib synergistically induce apoptosis in soft-tissue sarcomas

Soft-Tissue Sarcomas (STS) are mesenchymal malignancies with high heterogeneity that predominantly affect children and young adults. Despite routinely applied therapy strategies including radiotherapy, surgery and chemotherapy, the five-year survival rate of metastatic STS is only 50 %. Therefore, it is of high importance to focus on possible combinational therapies for the effective treatment of all kinds of STS. For such a therapy we combined the clinically approved BH3-mimetic drug ABT-199 (Venetoclax) with the proteasome inhibitor Bortezomib (Velcade). ABT-199 selectively inhibits the anti-apoptotic protein Bcl-2 whereas the proteasome inhibitor Bortezomib is effective, e.g., in multiple myeloma.

Sarcoma cell lines were incubated with ABT-199 and Bortezomib alone or in combination and apoptotic cell death was flow cytometric detected by analysis of mitochondrial membrane potential (TMRM) and exposure of phosphatidyl serine (Annexin V). To elucidate an underlying mechanism for apoptosis induction, we analyzed expression of members of the Bcl-2 family involved in the apoptosis pathway by Western Blotting and performed analogue experiments in knock-out cell lines.

Combined treatment with ABT-199 and Bortezomib showed synergistic cell death induction in several sarcoma cell lines including Rhabdomyosarcoma, Leiomyosarcoma and Synovial sarcoma. Loss of mitochondrial membrane potential and Annexin V staining revealed apoptosis as the underlying cell death mechanism. Interestingly, expression of Bok, a homologue of the pore-forming effector proteins Bax and Bak, was increased in response to ABT-199 and Bortezomib. Also, expression was increased for the BH3-only protein Noxa and its anti-apoptotic interaction partner Mcl-1. Knock-out (KO) of effector proteins Bax, Bak or Bok in the sarcoma cell line SW982 reduced apoptosis induction by ABT-199/Bortezomib with the most pronounced reduction in SW982/Bax-KO. Additional shRNA mediated knock-down of Noxa in Bax-KO, Bak-KO or Bok-KO SW982 cells further reduced apoptosis compared to Noxa knock-down alone.

ABT-199 and Bortezomib synergistically induce apoptotic cell death in various sarcoma cell lines concomitant with enhanced expression of the Bcl-2 proteins Bok, Noxa and Mcl-1. Hence, we suggest a mechanism in which the simultaneous inhibition of anti-apoptotic Bcl-2 by ABT-199 and the stabilization of pro-apoptotic proteins Bok and/or Noxa shift the equilibrium of BCL-2-proteins towards apoptosis. Experiments in Bax, Bak, Bok, and Noxa deficient SW982 cells indicate that Bax and Noxa are crucial for the observed synergistic effect. based on these results we propose the combined treatment with ABT-199 and Bortezomib as a new and highly promising therapy option for advanced STS. Future efforts, e.g. simultaneous knock-out of relevant Bcl-2 proteins, will unravel the detailed underlying mechanism of the observed synergistic cell death induction by ABT-199 and Bortezomib.

Citation Format: Sandra Weller, Alina Muenchow, Walter E. Aulitzky, Hans-Georg Kopp, Frank Essmann. ABT-199 and Bortezomib synergistically induce apoptosis in soft-tissue sarcomas [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 6227.

Quality of Surgery and Outcome in Localized Gastrointestinal Stromal Tumors Treated Within an International Intergroup Randomized Clinical Trial of Adjuvant Imatinib

Importance

The association between quality of surgery and overall survival in patients affected by localized gastrointestinal stromal tumors (GIST) is not completely understood.

Objective

To assess the risk of death with and without imatinib according to microscopic margins status (R0/R1) using data from a randomized study on adjuvant imatinib.

Design, Setting, and Participants

This is a post hoc observational study on patients included in the randomized, open-label, phase III trial, performed between December 2004 and October 2008. Median follow-up was 9.1 years (IQR, 8-10 years). The study was performed at 112 hospitals in 12 countries. Inclusion criteria were diagnosis of primary GIST, with intermediate or high risk of relapse; no evidence of residual disease after surgery; older than 18 years; and no prior malignancies or concurrent severe/uncontrolled medical conditions. Data were analyzed between July 17, 2017, and March 1, 2020.

Interventions

Patients were randomized after surgery to either receive imatinib (400 mg/d) for 2 years or no adjuvant treatment. Randomization was stratified by center, risk category (high vs intermediate), tumor site (gastric vs other), and quality of surgery (R0 vs R1). Tumor rupture was included in the R1 category but also analyzed separately.

Main Outcomes and Measures

Primary end point of this substudy was overall survival (OS), estimated using Kaplan-Meier method and compared between R0/R1 using Cox models adjusted for treatment and stratification factors.

Results

A total of 908 patients were included; 51.4% were men (465) and 48.6% were women (440), and the median age was 59 years (range, 18-89 years). One hundred sixty-two (17.8%) had an R1 resection, and 97 of 162 (59.9%) had tumor rupture. There was a significant difference in OS for patients undergoing an R1 vs R0 resection, overall (hazard ratio [HR], 2.05; 95% CI, 1.45-2.89) and by treatment arm (HR, 2.65; 95% CI, 1.37-3.75 with adjuvant imatinib and HR, 1.86; 95% CI, 1.16-2.99 without adjuvant imatinib). When tumor rupture was excluded, this difference in OS between R1 and R0 resections disappeared (HR, 1.05; 95% CI, 0.54-2.01).

Conclusions and Relevance

The difference in OS by quality of surgery with or without imatinib was associated with the presence of tumor rupture. When the latter was excluded, the presence of R1 margins was not associated with worse OS.

Trial Registration

ClinicalTrials.gov Identifier: NCT00103168.

Oral intake of lipopolysaccharide regulates toll-like receptor 4-dependent granulopoiesis

IMPACT STATEMENT

In our present study, we investigated the impact of LPS on neutrophil homeostasis and found that oral intake is sufficient to induce hematopoietic stem and progenitor cell fate decisions towards the neutrophil lineage independent of G-CSF. In addition, TLR4 has been identified as the indispensable sensor for oral LPS-modulated steady-state granulopoiesis. We provide evidence that the gastrointestinal microbiome is critical for neutrophil homeostasis, which has implications for patients being treated with chemotherapy or antimicrobial therapy, since both are significantly influencing the composition of the intestinal microbiome.

Phase III randomized, double-blind study of paclitaxel with and without everolimus in patients with advanced gastric or esophagogastric junction carcinoma who have progressed after therapy with a fluoropyrimidine/platinum-containing regimen (RADPAC)

The RADPAC trial evaluated paclitaxel with everolimus in patients with advanced gastroesophageal cancer (GEC) who have progressed after therapy with a fluoropyrimidine/platinum-containing regimen. Patients were randomly assigned to receive paclitaxel (80 mg/m² ) on day 1, 8 and 15 plus everolimus (10 mg daily, arm B) d1-d28 or placebo (arm A), repeated every 28 days. Primary end point was overall survival (OS). Efficacy was assessed in the intention-to-treat population and safety in all patients who received at least one dose of treatment. This trial is registered with ClinicalTrials.gov, number NCT01248403. Between October 2011 and September 2015, 300 patients (median age: 62 years; median lines prior therapy: 2; 47.7% of patients had prior taxane therapy) were randomly assigned (arm A, 150, arm B, 150). In the intention to treat population, there was no significant difference in progression-free survival (PFS; everolimus, 2.2 vs placebo, 2.07 months, HR 0.88, P = .3) or OS (everolimus, 6.1 vs placebo, 5.0 months, HR 0.93, P = .54). For patients with prior taxane use, everolimus improved PFS (everolimus, 2.7 vs placebo 1.8 months, HR 0.69, P = .03) and OS (everolimus, 5.8 vs placebo 3.9 months, HR 0.73, P = .07). Combination of paclitaxel and everolimus was associated with significantly more grade 3-5 mucositis (13.3% vs 0.7%; P < .001). The addition of everolimus to paclitaxel did not improve outcomes in pretreated metastatic gastric/gastroesophageal junction (GEJ) cancer. Activity was seen in the taxane pretreated group. Additional biomarker studies are planned to look for subgroups that may have a benefit.

A novel flow cytometry-based assay to measure compromised B cell receptor signaling as a prognostic factor in chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is the most common leukemia in adults. In the past years, new therapeutic approaches (e.g., ibrutinib or venetoclax) have been established and greatly improved treatment of CLL. However, complete control or cure of the disease have not been reached so far. Thus, reliable prognostic markers are an imperative for treatment decisions. Recent studies have revealed an essential role for B cell receptor (BCR) signaling in the pathogenesis, prognosis, and therapy of CLL. A heterogeneous response to receptor stimulation with anti-IgM treatment culminating in different calcium flux capabilities has been demonstrated by several authors. However, the methods employed have not reached clinical application. Here, we report on a flow cytometry-based assay to evaluate calcium flux capabilities in CLL and demonstrate that compromised BCR signaling with diminished calcium flux is associated with a significantly better clinical outcome and progression free survival. In summary, our data strongly support the role of compromised BCR signaling as an important prognostic marker in CLL and establish a novel diagnostic tool for its assessment in clinical settings.

Modulation of Immune Responses by Platelet-Derived ADAM10

Platelets have a crucial function in maintaining hemostasis. However, beyond their role in coagulation and thrombus formation, platelets have been implicated to affect various pathophysiological conditions such as infectious diseases, autoimmune disorders, and cancer. It is well-established that platelets aid local cancer growth by providing growth factors or contributing to cancer angiogenesis. In addition, they promote metastasis, among others by facilitation of tumor cell-extravasation and epithelial-to-mesenchymal-like transition as well as protecting metastasizing cancer cells from immunosurveillance. A variety of membrane-bound and soluble platelet-derived factors are involved in these processes, and many aspects of platelet biology in both health and disease are regulated by platelet-associated metalloproteinases and their inhibitors. Platelets synthesize (i) members of the matrix metalloproteinase (MMP) family and also inhibitors of MMPs such as members of the "tissue inhibitor of metalloproteinases" (TIMP) family as well as (ii) members of the "a disintegrin and metalloproteinase" (ADAM) family including ADAM10. Notably, platelet-associated metalloproteinase activity not only influences functions of platelets themselves: platelets can also induce expression and/or release of metalloproteinases e.g., in leukocytes or cancer cells, and ADAMs are emerging as important components by which platelets directly affect other cell types and function. This review outlines the function of metalloproteinases in platelet biology with a focus on ADAM10 and discusses the role of platelet-derived metalloproteinases in the interaction of platelets with components of the immune system and/or cancer cells.

Disease progression and defects in primary hemostasis as major cause of bleeding in multiple myeloma

BACKGROUND AND OBJECTIVES

In patients with multiple myeloma (MM), unexpected bleeding complications remain a major issue. Since routine coagulation parameters are often inconspicuous, diagnosis and treatment of the underlying coagulation disorders are challenging.

PATIENTS AND METHODS

In our single-center observational study, we analyzed 164 patients with MM for coagulation disorders and bleeding complications.

RESULTS

Prolonged closure times (CTs), measured by PFA-100, were the most common, abnormal coagulation test, found in 66% of bleeding patients vs 5% in non-bleeding, followed by qualitative defects of von Willebrand factor (VWF:CB/VWF:Ag ratios), found in 34% vs 1% in the non-bleeding group. Increased serum free light chains (SFLC) and SFLC ratios were significantly associated with prolonged CTs and acquired von Willebrand syndrome (AVWS). Prolonged CTs and AVWS were associated with disease progression, determined by dynamics of SFLC ratios (P < .001), serum creatinine level (P = .013), Beta-2 microglobulin (P = .03), LDH (P = .016), and bone marrow infiltration (P < .001). Of note, response to myeloma therapy was frequently correlated with normalization of coagulation parameters.

CONCLUSIONS

Bleeding complications in MM are predominantly caused by defects in primary hemostasis and associated with disease progression. In a peri-interventional workup, determination of CTs and VWF:CB/VWF:Ag ratios are of significant importance to assess bleeding risk.

Health-Related Quality of Life With Carboplatin-Paclitaxel or nab-Paclitaxel With or Without Pembrolizumab in Patients With Metastatic Squamous Non-Small-Cell Lung Cancer

PURPOSE

In the phase 3 KEYNOTE-407 study, the addition of pembrolizumab to carboplatin-paclitaxel/nab-paclitaxel significantly improved overall survival, progression-free survival, and objective response rate in patients with previously untreated metastatic squamous non-small-cell lung cancer (NSCLC), with little impact on severe toxicity. We present patient-reported outcomes (PROs) from KEYNOTE-407.

METHODS

Patients were randomly assigned to receive 4 cycles of pembrolizumab 200 mg or placebo once every 3 weeks plus carboplatin plus paclitaxel or nab-paclitaxel, followed by pembrolizumab or placebo for an additional 31 cycles. Health-related quality of life (HRQoL) was evaluated using the European Organisation for Research and Treatment of Cancer Treatment of Cancer Quality of Life Questionnaire-Core 30 (QLQ-C30) and Quality of Life Questionnaire-Lung Cancer Module 13 (QLQ-LC13). Key PRO endpoints were change from baseline to weeks 9 and 18 (during and after platinum therapy) in the QLQ-C30 global health status/quality of life (GHS/QoL) score and time to deterioration in the composite endpoint of cough, chest pain, or dyspnea from the QLQ-C30 and QLQ-LC13. Two-sided, nominal P values are provided.

RESULTS

A total of 554 and 553 patients completed ≥ 1 QLQ-C30 or ≥ 1 QLQ-LC13 assessment, respectively. GHS/QoL score improved for the pembrolizumab-combination group (least squares [LS] mean [95% CI] change from baseline: week 9, 1.8 [-0.9 to 4.4]; week 18, 4.3 [1.7 to 6.9]) and deteriorated in the placebo-combination group (week 9, -1.8 [-4.4 to 0.7]; week 18, -0.57 [-3.3 to 2.2]). Between-group differences were improved for the pembrolizumab-combination group (difference in LS mean scores: week 9, 3.6 [95% CI, 0.3 to 6.9], nominal P = .0337; week 18, 4.9 [1.4 to 8.3], nominal P = .0060). Median time to deterioration in cough, chest pain, or dyspnea was not reached in either group (hazard ratio, 0.79; 95% CI, 0.58 to 1.06]; nominal P = .125).

CONCLUSION

Addition of pembrolizumab to chemotherapy maintained or improved HRQoL measurements relative to baseline and improved HRQoL versus chemotherapy alone at weeks 9 and 18. These results support use of pembrolizumab plus chemotherapy as first-line therapy for metastatic squamous NSCLC.

Poly (ADP-Ribose) Polymerase-1 (PARP1) Deficiency and Pharmacological Inhibition by Pirenzepine Protects From Cisplatin-Induced Ototoxicity Without Affecting Antitumor Efficacy

Cisplatin remains an indispensable drug for the systemic treatment of many solid tumors. However, a major dose-limiting side-effect is ototoxicity. In some scenarios, such as treatment of germ cell tumors or adjuvant therapy of non-small cell lung cancer, cisplatin cannot be replaced without undue loss of efficacy. Inhibition of polyadenosine diphosphate-ribose polymerase-1 (PARP1), is presently being evaluated as a novel anti-neoplastic principle. Of note, cisplatin-induced PARP1 activation has been related to inner ear cell death. Thus, PARP1 inhibition may exert a protective effect on the inner ear without compromising the antitumor activity of cisplatin. Here, we evaluated PARP1 deficiency and PARP1 pharmacological inhibition as a means to protect the auditory hair cells from cisplatin-mediated ototoxicity. We demonstrate that cisplatin-induced loss of sensory hair cells in the organ of Corti is attenuated in PARP1-deficient cochleae. The PARP inhibitor pirenzepine and its metabolite LS-75 mimicked the protective effect observed in PARP1-deficient cochleae. Moreover, the cytotoxic potential of cisplatin was unchanged by PARP inhibition in two different cancer cell lines. Taken together, the results from our study suggest that the negative side-effects of cisplatin anti-cancer treatment could be alleviated by a PARP inhibition adjunctive therapy.

Atezolizumab in combination with carboplatin plus nab-paclitaxel chemotherapy compared with chemotherapy alone as first-line treatment for metastatic non-squamous non-small-cell lung cancer (IMpower130): a multicentre, randomised, open-label, phase 3 trial

BACKGROUND

Atezolizumab (a monoclonal antibody against PD-L1), which restores anticancer immunity, improved overall survival in patients with previously treated non-small-cell lung cancer and also showed clinical benefit when combined with chemotherapy as first-line treatment of non-small-cell lung cancer. IMpower130 aimed to assess the efficacy and safety of atezolizumab plus chemotherapy versus chemotherapy alone as first-line therapy for non-squamous non-small-cell lung cancer.

METHODS

IMpower130 was a multicentre, randomised, open-label, phase 3 study done in 131 centres across eight countries (the USA, Canada, Belgium, France, Germany, Italy, Spain, and Israel). Eligible patients were aged 18 years or older, and had histologically or cytologically confirmed stage IV non-squamous non-small-cell lung cancer, an Eastern Cooperative Oncology Group performance status of 0 or 1, and received no previous chemotherapy for stage IV disease. Patients were randomly assigned (2:1; permuted block [block size of six] with an interactive voice or web response system) to receive atezolizumab (1200 mg intravenously every 3 weeks) plus chemotherapy (carboplatin [area under the curve 6 mg/mL per min every 3 weeks] plus nab-paclitaxel [100 mg/m² intravenously every week]) or chemotherapy alone for four or six 21-day cycles followed by maintenance therapy. Stratification factors were sex, baseline liver metastases, and PD-L1 tumour expression. Co-primary endpoints were investigator-assessed progression-free survival and overall survival in the intention-to-treat wild-type (ie, EGFR^wt and ALK^wt) population. The safety population included patients who received at least one dose of the study drug. This study is registered with ClinicalTrials.gov, number NCT02367781.

FINDINGS

Between April 16, 2015, and Feb 13, 2017, 724 patients were randomly assigned and 723 were included in the intention-to-treat population (one patient died before randomisation, but was assigned to a treatment group; this patient was excluded from the intention-to-treat population) of the atezolizumab plus chemotherapy group (483 patients in the intention-to-treat population and 451 patients in the intention-to-treat wild-type population) or the chemotherapy group (240 patients in the intention-to-treat population and 228 patients in the intention-to-treat wild-type population). Median follow-up in the intention-to-treat wild-type population was similar between groups (18·5 months [IQR 15·2-23·6] in the atezolizumab plus chemotherapy group and 19·2 months [15·4-23·0] in the chemotherapy group). In the intention-to-treat wild-type population, there were significant improvements in median overall survival (18·6 months [95% CI 16·0-21·2] in the atezolizumab plus chemotherapy group and 13·9 months [12·0-18·7] in the chemotherapy group; stratified hazard ratio [HR] 0·79 [95% CI 0·64-0·98]; p=0·033) and median progression-free survival (7·0 months [95% CI 6·2-7·3] in the atezolizumab plus chemotherapy group and 5·5 months [4·4-5·9] in the chemotherapy group; stratified HR 0·64 [95% CI 0·54-0·77]; p<0·0001]). The most common grade 3 or worse treatment-related adverse events were neutropenia (152 [32%] of 473 in the atezolizumab plus chemotherapy group vs 65 [28%] of 232 in the chemotherapy group), anaemia (138 [29%] vs 47 [20%]), and decreased neutrophil count (57 [12%] vs 19 [8%]). Treatment-related serious adverse events were reported in 112 (24%) of 473 patients in the atezolizumab plus chemotherapy group and 30 (13%) of 232 patients in the chemotherapy group. Treatment-related (any treatment) deaths occurred in eight (2%) of 473 patients in the atezolizumab plus chemotherapy group and one (<1%) of 232 patients in the chemotherapy group.

INTERPRETATION

IMpower130 showed a significant and clinically meaningful improvement in overall survival and a significant improvement in progression-free survival with atezolizumab plus chemotherapy versus chemotherapy as first-line treatment of patients with stage IV non-squamous non-small-cell lung cancer and no ALK or EGFR mutations. No new safety signals were identified. This study supports the benefit of atezolizumab, in combination with platinum-based chemotherapy, as first-line treatment of metastatic non-small-cell lung cancer.

FUNDING

F. Hoffmann-La Roche.

Abstract CT200: IMpower130: Progression-free survival (PFS) and safety analysis from a randomized phase 3 study of carboplatin + nab-paclitaxel (CnP) with or without atezolizumab as first-line (1L) therapy in advanced non-squamous NSCLC

Background: Atezolizumab (atezo) (anti-PD-L1) monotherapy improves overall survival (OS) vs docetaxel in 2L+ NSCLC regardless of PD-L1 status; phase 3, 1L studies have shown clinical benefit of atezo plus chemotherapy and atezo in combination with bevacizumab and chemotherapy. IMpower130 (NCT02367781) evaluated atezo + CnP vs CnP in patients (pts) with measurable (RECIST v1.1) stage IV non-squamous NSCLC.

Methods: Pts (randomized 2:1) received atezo (1200 mg IV q3w) + CnP (carboplatin: AUC 6 q3w; nab-paclitaxel: 100 mg/m2 IV qw) (Arm A) or CnP (Arm B), for 4 or 6 21-day cycles and maintenance (Arm A: atezo until loss of clinical benefit; Arm B: best supportive care or pemetrexed q3w until disease progression [PD]). Crossover to atezo at PD was initially permitted for Arm B pts. Co-primary endpoints were investigator-assessed PFS and OS (ITT-WT population: EGFR-WT/ALK-negative). Secondary endpoints were OS and PFS (ITT population and by PD-L1 expression), response rate and safety. ITT population could be formally tested for OS/PFS if ITT-WT OS was positive.

Results: 723 ITT (679 ITT-WT) pts were enrolled. Statistically significant, clinically meaningful improvements in OS and statistically significant and clinically meaningful improvements in PFS (ITT and ITT-WT) were observed in Arm A vs Arm B (table). PFS and OS benefit was observed in all PD-L1 subgroups, and consistently across all subgroups, except in pts with liver metastases and EGFR/ALK genomic alterations. In treated pts, 73.2% (Arm A) vs 60.3% (Arm B) had grade 3-4 treatment-related adverse events.

Conclusions: Overall, IMpower130 showed statistically significant, clinically meaningful improvements in OS and statistically significant improvements in PFS with atezo + CnP, vs CnP, in 1L, stage IV non-squamous NSCLC, in this predominantly ITT-WT population. No new safety signals were identified.

Table.IMpower130 Efficacy AnalysesArm A Atezo + CnPArm B CnPITT-WTn = 451n = 228Median OS (95% CI)18.6 mo (16.0-21.2)13.9 mo (12.0-18.7)HR (95% CI; P value)0.79 (0.64-0.98; 0.033)12-mo OS (95% CI)63.1% (58.59-67.66)55.5% (48.89-62.17)Median PFS (95% CI)7.0 mo (6.2-7.3)5.5 mo (4.4-5.9)HR (95% CI; P value)0.64 (0.54-0.77; &lt; 0.0001)12-mo PFS (95% CI)29.1% (24.83-33.44)14.1% (9.37-18.76)n = 447n = 226Confirmed ORR (investigator assessed) (95% CI)49.2% (44.49-53.96)31.9% (25.84-38.36)n = 220n = 72Median DOR (95% CI)8.4 mo (6.9-11.8)6.1 mo (5.5-7.9)PD-L1 highan = 88n = 42Median OS (95% CI)17.4 mo (14.78-NA)16.9 mo (10.94-NA)HR (95% CI)0.84 (0.51-1.39)Median PFS (95% CI)6.4 mo (5.49-9.76)4.6 mo (3.22-7)HR (95% CI)0.51 (0.34-0.77)PD-L1 lowan = 128n = 65Median OS (95% CI)23.7 mo (18.63-NA)15.9 mo (12.32-25.63)HR (95% CI)0.70 (0.45-1.08)Median PFS (95% CI)8.3 mo (7.16-10.35)6.0 mo (5.29-6.93)HR (95% CI)0.61 (0.43-0.85)PD-L1 negativean = 235n = 121Median OS (95% CI)15.2 mo (12.88-19.15)12.0 mo (8.97-17.71)HR (95% CI)0.81 (0.61-1.08)Median PFS (95% CI)6.2 mo (5.52-7.16)4.7 mo (4.11-5.72)HR (95% CI)0.72 (0.56-0.91)ITTn = 483n = 240Median OS (95% CI)18.1 mo (15.3-20.8)13.9 mo (12.0-18.2)HR (95% CI; P value)0.80 (0.65-0.99; 0.039)Median PFS (95% CI)7.0 mo (6.3-7.3)5.6 mo (4.5-5.9)HR (95% CI; P value)0.65 (0.54-0.77; &lt; 0.0001)a PD-L1 high (TC3 or IC3): Patients with PD-L1 expression in ≥ 50% of tumor cells or ≥ 10% of tumor-infiltrating immune cells; PD-L1 low (TC1/2 or IC1/2): Patients with PD-L1 expression in ≥ 1% and &lt; 50% of tumor cells or ≥ 1% and &lt;10% of tumor-infiltrating immune cells; and PD-L1 negative (TC0 and IC0): Patients with PD-L1 expression in &lt;1% of tumor cells and &lt; 1% of tumor-infiltrating immune cells. Data cut-off: 15 March 2018. Minimum follow up: 13 months. NCT02367781.DOR, duration of response; HR, hazard ratio; IC, immune cells; ORR, objective response rate; OS, overall survival; PFS, progression-free survival; TC, tumor cells.

Citation Format: Howard L. West, Michael McCleod, Maen Hussein, Alessandro Morabito, Achim Rittmeyer, Henry J. Conter, Hans-Georg Kopp, Davey Daniel, Steven McCune, Tarek Mekhail, Alona Zer, Niels Reinmuth, Ahad Sadiq, Venice Archer, Tania Ochi Lohmann, Helen Jessop, Lijia Wang, Marcin Kowanetz, Alan Sandler, Federico Cappuzzo. IMpower130: Progression-free survival (PFS) and safety analysis from a randomized phase 3 study of carboplatin + nab-paclitaxel (CnP) with or without atezolizumab as first-line (1L) therapy in advanced non-squamous NSCLC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr CT200.

Atezolizumab in combination with carboplatin plus nab-paclitaxel chemotherapy compared with chemotherapy alone as first-line treatment for metastatic non-squamous non-small-cell lung cancer (IMpower130): a multicentre, randomised, open-label, phase 3 trial

BACKGROUND

Atezolizumab (a monoclonal antibody against PD-L1), which restores anticancer immunity, improved overall survival in patients with previously treated non-small-cell lung cancer and also showed clinical benefit when combined with chemotherapy as first-line treatment of non-small-cell lung cancer. IMpower130 aimed to assess the efficacy and safety of atezolizumab plus chemotherapy versus chemotherapy alone as first-line therapy for non-squamous non-small-cell lung cancer.

METHODS

IMpower130 was a multicentre, randomised, open-label, phase 3 study done in 131 centres across eight countries (the USA, Canada, Belgium, France, Germany, Italy, Spain, and Israel). Eligible patients were aged 18 years or older, and had histologically or cytologically confirmed stage IV non-squamous non-small-cell lung cancer, an Eastern Cooperative Oncology Group performance status of 0 or 1, and received no previous chemotherapy for stage IV disease. Patients were randomly assigned (2:1; permuted block [block size of six] with an interactive voice or web response system) to receive atezolizumab (1200 mg intravenously every 3 weeks) plus chemotherapy (carboplatin [area under the curve 6 mg/mL per min every 3 weeks] plus nab-paclitaxel [100 mg/m² intravenously every week]) or chemotherapy alone for four or six 21-day cycles followed by maintenance therapy. Stratification factors were sex, baseline liver metastases, and PD-L1 tumour expression. Co-primary endpoints were investigator-assessed progression-free survival and overall survival in the intention-to-treat wild-type (ie, EGFR^wt and ALK^wt) population. The safety population included patients who received at least one dose of the study drug. This study is registered with ClinicalTrials.gov, number NCT02367781.

FINDINGS

Between April 16, 2015, and Feb 13, 2017, 724 patients were randomly assigned and 723 were included in the intention-to-treat population (one patient died before randomisation, but was assigned to a treatment group; this patient was excluded from the intention-to-treat population) of the atezolizumab plus chemotherapy group (483 patients in the intention-to-treat population and 451 patients in the intention-to-treat wild-type population) or the chemotherapy group (240 patients in the intention-to-treat population and 228 patients in the intention-to-treat wild-type population). Median follow-up in the intention-to-treat wild-type population was similar between groups (18·5 months [IQR 15·2-23·6] in the atezolizumab plus chemotherapy group and 19·2 months [15·4-23·0] in the chemotherapy group). In the intention-to-treat wild-type population, there were significant improvements in median overall survival (18·6 months [95% CI 16·0-21·2] in the atezolizumab plus chemotherapy group and 13·9 months [12·0-18·7] in the chemotherapy group; stratified hazard ratio [HR] 0·79 [95% CI 0·64-0·98]; p=0·033) and median progression-free survival (7·0 months [95% CI 6·2-7·3] in the atezolizumab plus chemotherapy group and 5·5 months [4·4-5·9] in the chemotherapy group; stratified HR 0·64 [95% CI 0·54-0·77]; p<0·0001]). The most common grade 3 or worse treatment-related adverse events were neutropenia (152 [32%] of 473 in the atezolizumab plus chemotherapy group vs 65 [28%] of 232 in the chemotherapy group), anaemia (138 [29%] vs 47 [20%]), and decreased neutrophil count (57 [12%] vs 19 [8%]). Treatment-related serious adverse events were reported in 112 (24%) of 473 patients in the atezolizumab plus chemotherapy group and 30 (13%) of 232 patients in the chemotherapy group. Treatment-related (any treatment) deaths occurred in eight (2%) of 473 patients in the atezolizumab plus chemotherapy group and one (<1%) of 232 patients in the chemotherapy group.

INTERPRETATION

IMpower130 showed a significant and clinically meaningful improvement in overall survival and a significant improvement in progression-free survival with atezolizumab plus chemotherapy versus chemotherapy as first-line treatment of patients with stage IV non-squamous non-small-cell lung cancer and no ALK or EGFR mutations. No new safety signals were identified. This study supports the benefit of atezolizumab, in combination with platinum-based chemotherapy, as first-line treatment of metastatic non-small-cell lung cancer.

FUNDING

F. Hoffmann-La Roche.

Perioperative chemotherapy with fluorouracil plus leucovorin, oxaliplatin, and docetaxel versus fluorouracil or capecitabine plus cisplatin and epirubicin for locally advanced, resectable gastric or gastro-oesophageal junction adenocarcinoma (FLOT4): a randomised, phase 2/3 trial

BACKGROUND

Docetaxel-based chemotherapy is effective in metastatic gastric and gastro-oesophageal junction adenocarcinoma. This study reports on the safety and efficacy of the docetaxel-based triplet FLOT (fluorouracil plus leucovorin, oxaliplatin and docetaxel) as a perioperative therapy for patients with locally advanced, resectable tumours.

METHODS

In this controlled, open-label, phase 2/3 trial, we randomly assigned 716 patients with histologically-confirmed advanced clinical stage cT2 or higher or nodal positive stage (cN+), or both, resectable tumours, with no evidence of distant metastases, via central interactive web-based-response system, to receive either three pre-operative and three postoperative 3-week cycles of 50 mg/m² epirubicin and 60 mg/m² cisplatin on day 1 plus either 200 mg/m² fluorouracil as continuous intravenous infusion or 1250 mg/m² capecitabine orally on days 1 to 21 (ECF/ECX; control group) or four preoperative and four postoperative 2-week cycles of 50 mg/m² docetaxel, 85 mg/m² oxaliplatin, 200 mg/m² leucovorin and 2600 mg/m² fluorouracil as 24-h infusion on day 1 (FLOT; experimental group). The primary outcome of the trial was overall survival (superiority) analysed in the intention-to-treat population. This trial is registered with ClinicalTrials.gov, number NCT01216644.

FINDINGS

Between Aug 8, 2010, and Feb 10, 2015, 716 patients were randomly assigned to treatment in 38 German hospitals or with practice-based oncologists. 360 patients were assigned to ECF/ECX and 356 patients to FLOT. Overall survival was increased in the FLOT group compared with the ECF/ECX group (hazard ratio [HR] 0·77; 95% confidence interval [CI; 0.63 to 0·94]; median overall survival, 50 months [38·33 to not reached] vs 35 months [27·35 to 46·26]). The number of patients with related serious adverse events (including those occurring during hospital stay for surgery) was similar in the two groups (96 [27%] in the ECF/ECX group vs 97 [27%] in the FLOT group), as was the number of toxic deaths (two [<1%] in both groups). Hospitalisation for toxicity occurred in 94 patients (26%) in the ECF/ECX group and 89 patients (25%) in the FLOT group.

INTERPRETATION

In locally advanced, resectable gastric or gastro-oesophageal junction adenocarcinoma, perioperative FLOT improved overall survival compared with perioperative ECF/ECX.

FUNDING

The German Cancer Aid (Deutsche Krebshilfe), Sanofi-Aventis, Chugai, and Stiftung Leben mit Krebs Foundation.

Genomic Profiling Identifies Outcome-Relevant Mechanisms of Innate and Acquired Resistance to Third-Generation Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitor Therapy in Lung Cancer

PURPOSE

Third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) are effective in acquired resistance (AR) to early-generation EGFR TKIs in EGFR-mutant lung cancer. However, efficacy is marked by interindividual heterogeneity. We present the molecular profiles of pretreatment and post-treatment samples from patients treated with third-generation EGFR TKIs and their impact on treatment outcomes.

METHODS

Using the databases of two lung cancer networks and two lung cancer centers, we molecularly characterized 124 patients with EGFR p.T790M-positive AR to early-generation EGFR TKIs. In 56 patients, correlative analyses of third-generation EGFR TKI treatment outcomes and molecular characteristics were feasible. In addition, matched post-treatment biopsy samples were collected for 29 patients with progression to third-generation EGFR TKIs.

RESULTS

Co-occurring genetic aberrations were found in 74.4% of EGFR p.T790-positive samples (n = 124). Mutations in TP53 were the most frequent aberrations detected (44.5%; n = 53) and had no significant impact on third-generation EGFR TKI treatment. Mesenchymal-epithelial transition factor (MET) amplifications were found in 5% of samples (n = 6) and reduced efficacy of third-generation EGFR TKIs significantly (eg, median progression-free survival, 1.0 months; 95% CI, 0.37 to 1.72 v 8.2 months; 95% CI, 1.69 to 14.77 months; P ≤ .001). Genetic changes in the 29 samples with AR to third-generation EGFR TKIs were found in EGFR (eg, p.T790M loss, acquisition of p.C797S or p.G724S) or in other genes (eg, MET amplification, KRAS mutations).

CONCLUSION

Additional genetic aberrations are frequent in EGFR-mutant lung cancer and may mediate innate and AR to third-generation EGFR TKIs. MET amplification was strongly associated with primary treatment failure and was a common mechanism of AR to third-generation EGFR TKIs. Thus, combining EGFR inhibitors with TKIs targeting common mechanisms of resistance may delay AR.

Loss of NFAT2 expression results in the acceleration of clonal evolution in chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) can be defined as a clonal expansion of B cells with stereotypic BCRs. Somatic hypermutation of the BCR heavy chains (IGVH) defines a subgroup of patients with a better prognosis. In up to 10% of CLL cases, a transformation to an aggressive B cell lymphoma (Richter's syndrome) with a dismal prognosis can be observed over time. NFAT proteins are transcription factors originally identified in T cells, which also play an important role in B cells. The TCL1 transgenic mouse is a well-accepted model of CLL. Upon B cell-specific deletion of NFAT2, TCL1 transgenic mice develop a disease resembling human Richter's syndrome. Whereas TCL1 B cells exhibit tonic anergic BCR signaling characteristic of human CLL, loss of NFAT2 expression leads to readily activated BCRs indicating different BCR usage with altered downstream signaling. Here, we analyzed BCR usage in wild-type and TCL1 transgenic mice with and without NFAT2 deletion employing conventional molecular biology techniques and next-generation sequencing (NGS). We demonstrate that the loss of NFAT2 in CLL precipitates the selection of unmutated BCRs and the preferential usage of certain VDJ recombinations, which subsequently results in the accelerated development of oligoclonal disease.

A Chromatin Immunoprecipitation Assay to Identify Novel NFAT2 Target Genes in Chronic Lymphocytic Leukemia

Chronic lymphocytic leukemia (CLL) is characterized by the expansion of malignant B cell clones and represents the most common leukemia in western countries. The majority of CLL patients show an indolent course of the disease as well as an anergic phenotype of their leukemia cells, referring to a B cell receptor unresponsive to external stimulation. We have recently shown that the transcription factor NFAT2 is a crucial regulator of anergy in CLL. A major challenge in the analysis of the role of a transcription factor in different diseases is the identification of its specific target genes. This is of great significance for the elucidation of pathogenetic mechanisms and potential therapeutic interventions. Chromatin immunoprecipitation (ChIP) is a classic technique to demonstrate protein-DNA interactions and can, therefore, be used to identify direct target genes of transcription factors in mammalian cells. Here, ChIP was used to identify LCK as a direct target gene of NFAT2 in human CLL cells. DNA and associated proteins are crosslinked using formaldehyde and subsequently sheared by sonication into DNA fragments of approximately 200-500 base pairs (bp). Cross-linked DNA fragments associated with NFAT2 are then selectively immunoprecipitated from cell debris using an αNFAT2 antibody. After purification, associated DNA fragments are detected via quantitative real-time PCR (qRT-PCR). DNA sequences with evident enrichment represent regions of the genome which are targeted by NFAT2 in vivo. Appropriate shearing of the DNA and the selection of the required antibody are particularly crucial for the successful application of this method. This protocol is ideal for the demonstration of direct interactions of NFAT2 with target genes. Its major limitation is the difficulty to employ ChIP in large-scale assays analyzing the target genes of multiple transcription factors in intact organisms.

Validating Comprehensive Next-Generation Sequencing Results for Precision Oncology: The NCT/DKTK Molecularly Aided Stratification for Tumor Eradication Research Experience

Purpose

Rapidly evolving genomics technologies, in particular comprehensive next-generation sequencing (NGS), have led to exponential growth in the understanding of cancer biology, shifting oncology toward personalized treatment strategies. However, comprehensive NGS approaches, such as whole-exome sequencing, have limitations that are related to the technology itself as well as to the input source. Hence, clinical implementation of comprehensive NGS in a quality-controlled diagnostic workflow requires both the standardization of sequencing procedures and continuous validation of sequencing results by orthogonal methods in an ongoing program to enable the determination of key test parameters and continuous improvement of NGS and bioinformatics pipelines.

Patients and Methods

We present validation data on 220 patients who were enrolled between 2013 and 2016 in a multi-institutional, genomics-guided precision oncology program (Molecularly Aided Stratification for Tumor Eradication Research) of the National Center for Tumor Diseases Heidelberg and the German Cancer Consortium.

Results

More than 90% of clinically actionable genomic alterations identified by combined whole-exome sequencing and transcriptome sequencing were successfully validated, with varying frequencies of discordant results across different types of alterations (fusions, 3.7%; single-nucleotide variants, 2.6%; amplifications, 1.1%; overexpression, 0.9%; deletions, 0.6%). The implementation of new computational methods for NGS data analysis led to a substantial improvement of gene fusion calling over time.

Conclusion

Collectively, these data demonstrate the value of a rigorous validation program that partners with comprehensive NGS to successfully implement and continuously improve cancer precision medicine in a clinical setting.

CT-response patterns and the role of CT-textural features in inoperable abdominal/retroperitoneal soft tissue sarcomas treated with trabectedin

PURPOSE

To evaluate CT patterns and textural features of soft tissue sarcomas following trabectedin therapy as well as their suitability for predicting therapeutic response.

MATERIAL AND METHODS

A total of 31 patients (18 female, 13 male; mean age, 58.0years; range, 38-79years) with sarcoma under trabectedin as a third-line therapy between October 2008 and July 2017 underwent baseline and follow-up contrast-enhanced CT. Response evaluation was based on modifiedCHOI-criteria and RECIST1.1, classified as partial response(PR), stable disease(SD), progressive disease(PD). For CT-texture analysis (CTTA), mean, entropy and uniformity of intensity/skewness/entropy of co-occurrence matrix (COM) and contrast of neighboring-grey-level-dependence-matrix (NGLDM) were calculated.

RESULTS

Following CHOI-criteria, 9 patients achieved PR, 10 SD and 12 PD. RECIST1.1. classified patients into 5 PR, 15 SD and 11 PD. A frequent (n = 6/31; 19.3%) pattern of response was tumor liquefaction. In responders differences in entropy of entropy-NGLDM(p = 0.028) and uniformity-NGLDM(p = 0.021), in non-responders entropy of average(p = 0.039), deviation(p = 0.04) and uniformity of deviation(p = 0.013) occured between baseline and follow-up. Mean intensity and average were higher when liquefication occured(p = 0.03; p = 0.02), whereas mean deviation was lower(p = 0.02) at baseline compared to other response patterns. Differences in mean(p = 0.023), entropy(p = 0.049) and uniformity(p = 0.023) of entropy-NGLDM were found between responders and non-responders at follow-up. For the mean of heterogeneity a cut-off value was calculated for prediction of response in baseline CTTA (0.12; sensitivity 89%; specificity 77%).

CONCLUSION

A frequent pattern of response to trabectedin was tumor liquefication being responsible for pseudoprogression, therefore modifiedCHOI should be preferred. Single CT-textural features can be used complementarily for prediction and monitoring response to trabectedin.

Abstract 4336: Integrative genomic and transcriptomic analysis of leiomyosarcoma

Leiomyosarcomas (LMS) are malignant tumors of smooth-muscle origin that occur across age groups. The mechanisms underlying LMS development, including clinically actionable genetic vulnerabilities, are largely unknown, and few therapeutic options exist for LMS patients. To detect somatic mutations, copy number alterations, and structural rearrangements, we performed whole-exome and transcriptome sequencing of 49 and 37 LMS tumors, respectively, and performed integrative analysis. Recurrence analysis identified TP53, RB1, and ATRX as significantly mutated genes and various other cancer-associated genes mutated at low frequency, indicating substantial mutational heterogeneity. Copy number analysis revealed widespread chromosomal gains and losses and highly rearranged genomes in all tumors. Additionally, chromothripsis and whole-genome duplication were detected in 35% and 51% of cases, respectively. Principle component analysis and unsupervised hierarchical clustering of transcriptome data revealed three distinct subgroups of patients. Furthermore, we detected multiple non-recurrent fusion transcripts resulting from chromosomal rearrangements, many of which were predicted to result in loss of TP53 and RB1 function. In-depth analysis of these loci revealed protein-damaging microdeletions, intragenic or distal inversions, and exon skipping events as additional, previously unrecognized mechanisms of TP53 and RB1 disruption. Integration of whole-exome and transcriptome data demonstrated biallelic disruption of TP53 and RB1 in 92% and 94% of cases, respectively, and tumors with wildtype RB1 displayed loss of CDKN2A expression, overexpression of CCND1, or mutation of MAX resulting in CDK4 and CCND2 overexpression as alternative mechanisms of RB1 suppression. We also detected alternative lengthening of telomeres (ALT) in 78% of cases, and identified recurrent alterations in telomere maintenance genes such as ATRX, RBL2, and SP100, providing novel insight into the genetic basis of this mechanism. Finally, most tumors displayed hallmarks of “BRCAness”, including alterations in homologous recombination DNA repair genes and enrichment of specific mutational signatures, and cultured LMS cells were sensitive towards olaparib and cisplatin. This comprehensive genomic and transcriptomic analysis has unveiled that LMS is characterized by mutational heterogeneity, genomic instability, near-universal inactivation of TP53 and RB1, and frequent whole-genome duplication. Furthermore, we have established that most LMS tumors rely on ALT to escape replicative senescence, and identified recurrent alterations in a broad spectrum of telomere maintenance genes. Finally, our findings uncover “BRCAness” as potentially actionable feature of LMS tumors, and provide a rich resource for guiding future investigations into the mechanisms underlying LMS development and the design of novel therapeutic strategies.

Citation Format: Priya Chudasama, Sadaf Mughal, Mathijs Sanders, Daniel Hübschmann, Inn Chung, Aurélie Ernst, Bernd Kasper, Hans-Georg Kopp, Sebastian Bauer, Karsten Rippe, Benedikt Brors, Marcus Renner, Peter Hohenberger, Claudia Scholl, Stefan Fröhling. Integrative genomic and transcriptomic analysis of leiomyosarcoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4336.

Impact of surgery in patients with metastatic soft tissue sarcoma: A monocentric retrospective analysis

Background and Objectives

The role of local surgical procedures in patients with metastatic soft tissue sarcoma is still undefined. Few retrospective studies have reported survival benefits for patients with pulmonary metastases after complete surgical resection. Treatment decisions are therefore mainly based on personal experiences rather than on reproducible knowledge.

Method

A total of 237 patients with metastatic sarcoma, treated between 1982 and 2015 at the University Hospital Tuebingen, Germany, were eligible for inclusion. Out of the 237 screened patients, 102 patients underwent at least one metastasectomy. Overall survival was defined as the primary endpoint in this study. For association of non‐linear relationship to the endpoint, significant prognostic factors were included into a recursive partitioning model. A subgroup analysis for long‐term survivors was also performed.

Results

The median overall survival was 64 months. The 3‐, 5‐, 10‐, and 20‐years overall survival rates were 70.7%, 50.3%, 24.7%, and 14.8%, respectively. The number of resections and the progression‐free intervals were independent prognostic factors in three statistical models.

Conclusion

Repeated resections of metastases from different localizations are a strong predictor for prolonged survival. We suggest that the progression‐free interval after metastasectomy should be considered as a predictive factor for benefit from further surgery.