First-In-Human Phase I Study of Tinengotinib (TT-00420), a Multiple Kinase Inhibitor, as a Single Agent in Patients With Advanced Solid Tumors

PURPOSE

This first-in-human phase I dose-escalation study evaluated the safety, pharmacokinetics, and efficacy of tinengotinib (TT-00420), a multi-kinase inhibitor targeting fibroblast growth factor receptors 1-3 (FGFRs 1-3), Janus kinase 1/2, vascular endothelial growth factor receptors, and Aurora A/B, in patients with advanced solid tumors.

PATIENTS AND METHODS

Patients received tinengotinib orally daily in 28-day cycles. Dose escalation was guided by Bayesian modeling using escalation with overdose control. The primary objective was to assess dose-limiting toxicities (DLTs), maximum tolerated dose (MTD), and dose recommended for dose expansion (DRDE). Secondary objectives included pharmacokinetics and efficacy.

RESULTS

Forty-eight patients were enrolled (dose escalation, n = 40; dose expansion, n = 8). MTD was not reached; DRDE was 12 mg daily. DLTs were palmar-plantar erythrodysesthesia syndrome (8 mg, n = 1) and hypertension (15 mg, n = 2). The most common treatment-related adverse event was hypertension (50.0%). In 43 response-evaluable patients, 13 (30.2%) achieved partial response (PR; n = 7) or stable disease (SD) ≥ 24 weeks (n = 6), including 4/11 (36.4%) with FGFR2 mutations/fusions and cholangiocarcinoma (PR n = 3; SD ≥ 24 weeks n = 1), 3/3 (100.0%) with hormone receptor (HR)-positive/HER2-negative breast cancer (PR n = 2; SD ≥ 24 weeks n = 1), 2/5 (40.0%) with triple-negative breast cancer (TNBC; PR n = 1; SD ≥ 24 weeks n = 1), and 1/1 (100.0%) with castrate-resistant prostate cancer (CRPC; PR). Four of 12 patients (33.3%; HR-positive/HER2-negative breast cancer, TNBC, prostate cancer, and cholangiocarcinoma) treated at DRDE had PRs. Tinengotinib's half-life was 28-34 hours.

CONCLUSIONS

Tinengotinib was well tolerated with favorable pharmacokinetic characteristics. Preliminary findings indicated potential clinical benefit in FGFR inhibitor-refractory cholangiocarcinoma, HER2-negative breast cancer (including TNBC), and CRPC. Continued evaluation of tinengotinib is warranted in phase II trials.

Phase I Study of mTORC1/2 Inhibitor Sapanisertib (CB-228/TAK-228) in Combination with Metformin in Patients with mTOR/AKT/PI3K Pathway Alterations and Advanced Solid Malignancies

BACKGROUND

Sapanisertib (CB-228/TAK-228) is a potent, selective ATP-competitive, dual inhibitor of mTORC1/2. Metformin is thought to inhibit the mTOR pathway through upstream activation of 5'-AMP-activated protein kinase (AMPK) suggesting combination therapy may enhance antitumor activity of sapanisertib. We report preliminary safety, tolerability, and efficacy from the dose-escalation study of sapanisertib in combination with metformin in patients with advanced solid tumors.

METHODS

Patients with advanced metastatic solid tumors resistant or refractory to standard treatment, with and without mTOR/AKT/PI3K pathway alterations, received sapanisertib 3 or 4 mg daily together with metformin once to three times daily (500-1,500 mg). All patients underwent 14-day titration period for metformin in cycle 1. Tumor measurements were performed following cycle 2 and subsequently every 8 weeks.

RESULTS

A total of 30 patients were enrolled across four cohorts (3 mg/500 mg; 3 mg/1,000 mg, 4 mg/1,000 mg; 4 mg/1,500 mg). 19 were female (63%), median age was 57 (range: 30-77), all were Eastern Cooperative Oncology Group performance status 1. Tumor types included sarcoma (6), breast (4), ovarian (4), head and neck (3), colorectal (2), lung (2), renal cell (2), endometrial (2), gastroesophageal junction (1), prostate (1), stomach (1), urachus (1), and cervical cancer (1). Median number of prior lines of therapy was 4. Most common genomic alterations included PIK3CA (27%), PTEN (17%), AKT1/2 (10%), mTOR (10%). Of 30 patients evaluable for response, 4 patients achieved partial response (PR); 15 patients achieved stable disease (SD) as best response. Disease control rate (PR+SD) was 63%. Of the responders in PR, 3 of 4 patients had documented PTEN mutations (3/5 patients enrolled with PTEN mutations had PR); 2 of 4 of patients in PR had comutations (patient with leiomyosarcoma had both PTEN and TSC; patient with breast cancer had both PTEN and STK11); 1 of 4 patients in PR had AKT and mTOR mutation; tumor types included leiomyosarcoma (n = 2), breast (n = 1), and endometrial cancer (n = 1). Most common treatment-emergent adverse events included nausea, anorexia, diarrhea, and rash. Grade (G) 3-5 treatment-related adverse events included hyperglycemia (4/30; 13%), fatigue (2/30; 7%), hypertriglyceridemia (1/30; 3%), rash (2/20; 7%), diarrhea (2/30; 7%), creatinine increase (1/30; 3%), acidosis (1/30; 3%). No dose-limiting toxicities (DLT) were reported in the 3 mg/500 mg cohort. One of 6 patient had DLT in the 3 mg/1,000 mg cohort (G3 diarrhea) and 2 of 11 patients had DLTs in the 4 mg/1,500 mg cohort (G3 fatigue, G3 rash). 4 mg/1,000 mg was defined as the MTD.

CONCLUSIONS

The safety profile of mTORC1/2 inhibitor sapanisertib in combination with metformin was generally tolerable, with antitumor activity observed in patients with advanced malignancies harboring PTEN mutations and AKT/mTOR pathway alterations.

SIGNIFICANCE

Sapanisertib (CB-228/TAK-228) is a potent, selective ATP-competitive, next-generation dual inhibitor of mTORC1/2. Metformin is thought to inhibit the mTOR pathway through upstream activation of AMPK suggesting combination therapy may enhance antitumor activity of sapanisertib. This dose-escalation study of sapanisertib and metformin in advanced solid tumors and mTOR/AKT/PI3K pathway alterations, demonstrates safety, tolerability, and early clinical activity in advanced malignancies harboring PTEN mutations and AKT/mTOR pathway alterations.Clinical trial information: NCT03017833.

Phase 1/2 trial of avelumab combined with utomilumab (4-1BB agonist), PF-04518600 (OX40 agonist), or radiotherapy in patients with advanced gynecologic malignancies

BACKGROUND

Immune checkpoint blockade has shown mixed results in advanced/recurrent gynecologic malignancies. Efficacy may be improved through costimulation with OX40 and 4-1BB agonists. The authors sought to evaluate the safety and efficacy of avelumab combined with utomilumab (a 4-1BB agonist), PF-04518600 (an OX40 agonist), and radiotherapy in patients with recurrent gynecologic malignancies.

METHODS

The primary end point in this six-arm, phase 1/2 trial was safety of the combination regimens. Secondary end points included the objective response rate (ORR) according to Response Evaluation Criteria in Solid Tumors and immune-related Response Evaluation Criteria in Solid Tumors, the disease control rate (DCR), the duration of response, progression-free survival, and overall survival.

RESULTS

Forty patients were included (35% with cervical cancer, 30% with endometrial cancer, and 35% with ovarian cancer). Most patients (n = 33; 83%) were enrolled in arms A-C (no radiation). Among 35 patients who were evaluable for efficacy, the ORR was 2.9%, and the DCR was 37.1%, with a median duration of stable disease of 5.4 months (interquartile range, 4.1-7.3 months). Patients with cervical cancer in arm A (avelumab and utomilumab; n = 9 evaluable patients) achieved an ORR of 11% and a DCR of 78%. The median progression-free survival was 2.1 months (95% CI, 1.8-3.5 months), and overall survival was 9.4 months (95% CI, 5.6-11.9 months). No dose-limiting toxicities or grade 3-5 immune-related adverse events were observed.

CONCLUSIONS

The findings from this trial highlight that, in heavily pretreated patients with gynecologic cancer, even multidrug regimens targeting multiple immunologic pathways, although safe, did not produce significant responses. A DCR of 78% in patients with cervical cancer who received avelumab and utomilumab indicates that further research on this combination in select patients may be warranted.

Autologous engineered T cell receptor therapy in advanced cancer

To overcome challenges associated with adoptive cell therapy (ACT), we developed a personalized autologous T-cell therapy program. Patients with advanced cancer with HLA-A *02:01 allele and tumor expression of PRAME, MAGEA1, MAGEA4, MAGEA8, NY-ESO-1, COL6A3 exon 6, MXRA5, and/or MMP1 underwent leukapheresis and T-cell product manufacturing. Patients received lymphodepletion, IMA101 infusion and interleukin 2 for 14 days. Of 214 screened patients, 14 were treated (6, IMA101; 8, IMA101 and atezolizumab). The most common adverse events were cytokine release syndrome (G1, n = 6; G2, n = 4) and cytopenia. At 6 weeks, 12 (85.7%) patients had stable disease. Three patients had prolonged disease stabilization for 12.9, 7.3, and 13.7 months, respectively. The median progression-free survival and overall survival were 3.4 months and 9.4 months, respectively. Target-specific T cells expanded to constitute up to 78.7% of CD8+ cells. In conclusion, IMA101 was feasible and well tolerated, leveraging the potential of multi-targeted ACT that warrants further investigation.

A Phase I Trial of Bevacizumab and Temsirolimus in Combination With Valproic Acid in Advanced Solid Tumors

BACKGROUND

Preclinical models suggest synergy between anti-angiogenesis therapy, mammalian target of rapamycin (mTOR), and histone deacetylase inhibitors to promote anticancer activity.

METHODS

This phase I study enrolled 47 patients between April 2012 and 2018 and determined safety, maximum tolerated dose (MTD), and dose-limiting toxicities (DLTs) when combining bevacizumab, temsirolimus, and valproic acid in patients with advanced cancer.

RESULTS

Median age of enrolled patients was 56 years. Patients were heavily pretreated with a median of 4 lines of prior therapy. Forty-five patients (95.7%) experienced one or more treatment-related adverse events (TRAEs). Grade 3 TRAEs were lymphopenia (14.9%), thrombocytopenia (8.5%), and mucositis (6.4%). Grade 4 TRAEs included lymphopenia (2.1%) and CNS cerebrovascular ischemia (2.1%). Six patients developed DLTs across 10 dose levels with grade 3 infection, rash, mucositis, bowel perforation, elevated lipase, and grade 4 cerebrovascular ischemia. The MTD was dose level 9 (bevacizumab 5 mg/kg days 1 and 15 intravenously (IV) plus temsirolimus 25 mg days 1, 8, 15, and 22 IV and valproic acid 5 mg/kg on days 1-7 and 15-21 per orally (PO)). Objective response rate (ORR) was 7.9% with confirmed partial response (PRs) in 3 patients (one each in parotid gland, ovarian, and vaginal cancers). Stable disease (SD) ≥+6 months was seen in 5 patients (13.1%). Clinical benefit state (CBR: PR + SD ≥+6 months) was 21%.

CONCLUSION

Combination therapy with bevacizumab, temsirolimus, and valproic acid was feasible, but there were numerous toxicities, which will require careful management for future clinical development (ClinicalTrials.gov Identifier: NCT01552434).

Molecular tumour boards - current and future considerations for precision oncology

Over the past 15 years, rapid progress has been made in developmental therapeutics, especially regarding the use of matched targeted therapies against specific oncogenic molecular alterations across cancer types. Molecular tumour boards (MTBs) are panels of expert physicians, scientists, health-care providers and patient advocates who review and interpret molecular-profiling results for individual patients with cancer and match each patient to available therapies, which can include investigational drugs. Interpretation of the molecular alterations found in each patient is a complicated task that requires an understanding of their contextual functional effects and their correlations with sensitivity or resistance to specific treatments. The criteria for determining the actionability of molecular alterations and selecting matched treatments are constantly evolving. Therefore, MTBs have an increasingly necessary role in optimizing the allocation of biomarker-directed therapies and the implementation of precision oncology. Ultimately, increased MTB availability, accessibility and performance are likely to improve patient care. The challenges faced by MTBs are increasing, owing to the plethora of identifiable molecular alterations and immune markers in tumours of individual patients and their evolving clinical significance as more and more data on patient outcomes and results from clinical trials become available. Beyond next-generation sequencing, broader biomarker analyses can provide useful information. However, greater funding, resources and expertise are needed to ensure the sustainability of MTBs and expand their outreach to underserved populations. Harmonization between practice and policy will be required to optimally implement precision oncology. Herein, we discuss the evolving role of MTBs and current and future considerations for their use in precision oncology.

Recommendations for Cell-Free DNA Assay Validations: A Joint Consensus Recommendation of the Association for Molecular Pathology and College of American Pathologists

Diagnosing, selecting therapy for, and monitoring cancer in patients using a minimally invasive blood test represents a significant advance in precision medicine. Wide variability exists in how circulating tumor DNA (ctDNA) assays are developed, validated, and reported in the literature, which hinders clinical adoption and may negatively impact patient care. Standardization is needed for factors affecting ctDNA assay performance and reporting, including pre-analytical variables, analytical considerations, and elements of laboratory assay reporting. The Association for Molecular Pathology Clinical Practice Committee's Liquid Biopsy Working Group (LBxWG), including organizational representation from the American Society of Clinical Oncology and the College of American Pathologists, has undertaken a full-text data extraction of 1228 ctDNA publications that describe assays performed in patients with lymphoma and solid tumor malignancies. With an emphasis on clinical assay validation, the LBxWG has developed a set of 13 best practice consensus recommendations for validating, reporting, and publishing clinical ctDNA assays. Recommendations include reporting key pre-analytical considerations and assay performance metrics; this analysis demonstrates these elements are inconsistently included in publications. The LBxWG recommendations are intended to assist clinical laboratories with validating and reporting ctDNA assays and to ensure high-quality data are included in publications. It is expected that these recommendations will need to be updated as the body of literature continues to mature.

Reprogramming T cell differentiation and exhaustion in CAR-T cell therapy

T cell differentiation is a highly regulated, multi-step process necessary for the progressive establishment of effector functions, immunological memory, and long-term control of pathogens. In response to strong stimulation, as seen in severe or chronic infections or cancer, T cells acquire a state of hypo-responsiveness known as exhaustion, limiting their effector function. Recent advances in autologous chimeric antigen receptor (CAR)-T cell therapies have revolutionized the treatment of hematologic malignancies by taking advantage of the basic principles of T cell biology to engineer products that promote long-lasting T cell response. However, many patients' malignancies remain unresponsive to treatment or are prone to recur. Discoveries in T cell biology, including the identification of key regulators of differentiation and exhaustion, offer novel opportunities to have a durable impact on the fate of CAR-T cells after infusion. Such next-generation CAR-T cell therapies and their clinical implementation may result in the next leap forward in cancer treatment for selected patients. In this context, this review summarizes the foundational principles of T cell differentiation and exhaustion and describes how they can be utilized and targeted to further improve the design and efficacy of CAR-T cell therapies.

Multidisciplinary Care of a Large Brain Metastasis in a Patient with Hormone-Receptor-Positive Breast Cancer with Ataxia-Telangiectasia Mutation

Poly (adenosine diphosphate-ribose) polymerase inhibitors (PARP)i are emerging as standard oncology treatments in various tumor types. The indications will expand as PARPi are being investigated in various breast cancer subtypes. Currently, except for BRCA1/2 mutation carriers with human epidermal growth factor receptor 2 (HER2)-negative breast cancer, there is inadequate identification of predictive biomarkers of response. We present a 57-year-old woman with metastatic breast cancer, hormone-receptor-positive, HER2 negative with a germline ataxia-telangiectasia mutation with a large brain metastasis with clinical benefit to talazoparib. This case report exemplifies the importance of the multidisciplinary management of patients with brain metastases and personalized biomarker selected treatment.

Feasibility and Safety of Personalized, Multi-Target, Adoptive Cell Therapy (IMA101): First-in-Human Clinical Trial in Patients with Advanced Metastatic Cancer

IMA101 is an actively personalized, multi-targeted adoptive cell therapy (ACT), whereby autologous T cells are directed against multiple novel defined peptide-HLA (pHLA) cancer targets. HLA-A*02:01-positive patients with relapsed/refractory solid tumors expressing ≥1 of 8 predefined targets underwent leukapheresis. Endogenous T cells specific for up to 4 targets were primed and expanded in vitro. Patients received lymphodepletion (fludarabine, cyclophosphamide), followed by T-cell infusion and low-dose IL2 (Cohort 1). Patients in Cohort 2 received atezolizumab for up to 1 year (NCT02876510). Overall, 214 patients were screened, 15 received lymphodepletion (13 women, 2 men; median age, 44 years), and 14 were treated with T-cell products. IMA101 treatment was feasible and well tolerated. The most common adverse events were cytokine release syndrome (Grade 1, n = 6; Grade 2, n = 4) and expected cytopenias. No patient died during the first 100 days after T-cell therapy. No neurotoxicity was observed. No objective responses were noted. Prolonged disease stabilization was noted in three patients lasting for 13.7, 12.9, and 7.3 months. High frequencies of target-specific T cells (up to 78.7% of CD8+ cells) were detected in the blood of treated patients, persisted for >1 year, and were detectable in posttreatment tumor tissue. Individual T-cell receptors (TCR) contained in T-cell products exhibited broad variation in TCR avidity, with the majority being low avidity. High-avidity TCRs were identified in some patients' products. This study demonstrates the feasibility and tolerability of an actively personalized ACT directed to multiple defined pHLA cancer targets. Results warrant further evaluation of multi-target ACT approaches using potent high-avidity TCRs. See related Spotlight by Uslu and June, p. 865.

Impact of Biomarker-Matched Therapies on Outcomes in Patients with Sarcoma Enrolled in Early-Phase Clinical Trials (SAMBA 101)

PURPOSE

Developing new therapeutics for any of the more than 100 sarcoma subtypes presents a challenge. After progression from standard therapies, patients with sarcoma may be referred for enrollment in early-phase trials. This study aimed to investigate whether enrollment in biomarker-matched early-phase clinical trials leads to better outcomes for patients with advanced sarcoma.

EXPERIMENTAL DESIGN

In this retrospective analysis, investigational treatment characteristics and longitudinal survival outcomes were analyzed in patients with biopsy-confirmed sarcoma enrolled in early-phase trials at MD Anderson Cancer Center from May 2006 to July 2021.

RESULTS

Five hundred eighty-seven patients were included [405 soft tissue, 122 bone, 60 gastrointestinal stromal tumor (GIST); median of three prior lines of therapy]. Most common subtypes were leiomyosarcoma (17.2%), liposarcoma (14.0%), and GIST (10.2%). Molecular testing was available for 511 patients (87.1%); 221 patients (37.6%) were treated in matched trials. Overall response rate was 13.1% matched compared with 4.9% in unmatched (P < 0.001); the clinical benefit rate at 6 months was 43.9% vs. 19.9% (P < 0.001). Progression-free survival was longer for patients in matched trials (median, 5.5 vs. 2.4 months; P < 0.001), and overall survival was also superior for patients in matched trials (median, 21.5 vs. 12.3 months; P < 0.001). The benefit of enrollment in matched trials was maintained when patients with GIST were excluded from the analysis.

CONCLUSIONS

Enrollment in biomarker-matched early-phase trials is associated with improved outcomes in heavily pretreated patients with metastatic sarcoma. Molecular testing of tumors from patients with advanced sarcoma and enrollment in matched trials is a reasonable therapeutic strategy.

Phase I study of sapanisertib with carboplatin and paclitaxel in mTOR pathway altered solid malignancies

Pre-clinically, the mTORC1/2 inhibitor sapanisertib restored sensitivity to platinums and enhanced paclitaxel-induced cancer cell killing. NCT03430882 enrolled patients with mTOR pathway aberrant tumors to receive sapanisertib, carboplatin and paclitaxel. Primary objective was safety and secondary objectives were clinical response and survival. One patient had a dose-limiting toxicity at dose level 4. There were no unanticipated toxicities. Grade 3-4 treatment-related adverse events included anemia (21%), neutropenia (21%), thrombocytopenia (10.5%), and transaminitis (5%). Of 17 patients evaluable for response, 2 and 11 patients achieved partial response and stable disease, respectively. Responders included a patient with unclassified renal cell carcinoma harboring EWSR1-POU5F1 fusion and a patient with castrate resistant prostate cancer harboring PTEN loss. Median progression free survival was 3.84 months. Sapanisertib in combination with carboplatin plus paclitaxel demonstrated a manageable safety profile, with preliminary antitumor activity observed in advanced malignancies harboring mTOR pathway alterations.

Phase 1b study of combined selinexor and eribulin for the treatment of advanced solid tumors and triple-negative breast cancer

BACKGROUND

Selinexor (KPT-330) is a potent inhibitor of exportin 1 (XPO1), in turn inhibiting tumor growth. Selinexor enhances the antitumor efficacy of eribulin in triple-negative breast cancer (TNBC) in vitro and in vivo. Given the unmet medical need in TNBC and sarcoma, the authors explored the safety and efficacy of this combination.

METHODS

The authors conducted a phase 1b trial of combined selinexor and eribulin using a 3 + 3 dose-escalation design in patients who had advanced solid tumors and in those who had TNBC in a dose-expansion cohort.

RESULTS

Patients with TNBC (N = 19), sarcoma (N = 9), and other cancers (N = 3) were enrolled in the dose-escalation cohort (N = 10) and in the dose-expansion cohort (N = 21). The median number lines of prior therapy received was four (range, from one to seven prior lines). The most common treatment-related adverse events for selinexor were nausea (77%), leukopenia (77%), anemia (68%), neutropenia (68%), and fatigue (48%). One dose-limiting toxicity occurred at the first dose level with prolonged grade 3 neutropenia. The recommended phase 2 dose was 80 mg of selinexor orally once per week and 1 mg/m² eribulin on days 1 and 8 intravenously every 3 weeks. The objective response rate (ORR) was 10% in three patients. In the dose-escalation cohort, the ORR was 10%, whereas six patients with had stable disease. In the TNBC dose-expansion cohort (n = 18), ORR was 11%, and there were two confirmed partial responses with durations of 10.8 and 19.1 months (ongoing).

CONCLUSIONS

Selinexor and eribulin had an acceptable toxicity profile and modest overall efficacy with durable responses in select patients.

PLAIN LANGUAGE SUMMARY

Effective therapies for advanced, triple-negative breast cancer and sarcoma represent an unmet need. Exportin 1 is associated with the transport of cancer-related proteins. Preclinical studies have demonstrated tumor growth inhibition and enhanced tumor sensitivity in patients who receive selinexor combined with eribulin. In this phase 1b study, the authors evaluated the safety profile and clinical activity of the combination of selinexor, a potent oral inhibitor of exportin 1, and eribulin in patients with advanced cancers enriched for triple-negative breast cancer or sarcoma. The combination was well tolerated; most adverse events were mild or moderate, reversible, and managed with dose modifications or growth factor support. The combination of selinexor and eribulin produced an antitumor response, particularly in some patients with triple-negative breast cancer. This work lays the foundation for prospective investigations of the role of selinexor and eribulin in the treatment of triple-negative breast cancer.

Abstract 6181: Dynamic changes in monocyte and reticulocyte counts predict mechanism-based anemia development and recovery during ATR inhibitor treatment in phase I/II trials

Introduction: Clinical trials are exploring ATR inhibitors (ATRi) in genomically selected contexts. However, dose-dependent anemia has limited the therapeutic index of this class. We hypothesized that monocytes and reticulocytes are more vulnerable to ATRi due to their lack of base excision repair and high levels of oxidative stress, respectively. We sought to examine the kinetics of decline and recovery of red blood cell (RBC) and reticulocyte indices, in relation to hemoglobin (Hb), in the first 28 days after ATRi initiation.

Methods: We retrospectively retrieved peripheral blood cell indices from complete blood count (CBC) reports of patients (pts) pre- and during treatment with an oral ATRi on phase I/II trials at our center. Pts received ATRi monotherapy or in combination with a PARP inhibitor (ATRi+PARPi) in dose-escalation and expansion cohorts, which included ATRi at potentially toxic doses. We applied linear mixed effect models to evaluate the joint evolution of Hb and other RBC or reticulocyte indices over time via bivariate analysis. A random intercept was included in the model to account for the longitudinal nature of the data and a variance component option for the covariance structure was specified to model a different variance component for each index of interest. To assess if Hb decline was preceded by decline in the index of interest from baseline, piecewise regression models were used to estimate break points, defined as the time point where the fitted functions intersect, of each index. Log transformed data with a base of 2, were noted to have more symmetric distributions, and were used in the analyses. The time variable assessed was days from cycle 1 day 1 of ATRi. A two-sided p value &lt;0.05 was considered statistically significant.

Results: 35,007 indices from 1,843 CBC of 119 pts treated with an ATRi from 10/2017 to 1/2022 were analyzed. 110 (92.4%) pts received ATRi, 9 (7.6%) received ATRi+PARPi. Monocytes (-0.120 vs -0.022, p &lt;0.0001) and reticulocytes (-0.140 vs -0.022, p &lt;0.0001) declined at a faster rate compared with Hb. Time to monocyte and reticulocyte nadir after ATRi initiation was 8.9 and 5.8 days, respectively, while time to Hb nadir was 19.5 days. Conversely, RBC (-0.020 vs -0.023, p=0.410), MCV (-0.002 vs -0.022, p &lt;0.0001) and MCH (-0.001 vs -0.022, p&lt;0.0001) declined at a slower rate than Hb. Time to RBC, MCV and MCH nadir after ATRi initiation was 26.3, 18.7 and 15.0 days, respectively. After reaching their individual index nadir, monocytes (0.004 vs 0.001, p &lt;0.0001) and reticulocytes (0.005 vs 0.0005, p &lt;0.0001) increased more quickly than Hb.

Conclusions: Charting the kinetics of CBC index evolution in relation to Hb identified peripheral monocytes and reticulocytes as relevant blood indices that herald Hb decline. Our findings may inform patient monitoring strategies to mitigate hematologic toxicity on future ATRi trials.

Citation Format: Natalie Y. Ngoi, Heather Y. Lin, Ecaterina Dumbrava, Siqing Fu, Daniel D. Karp, Aung Naing, Shubham Pant, Sarina A. Piha-Paul, Jordi Rodon, Vivek Subbiah, Apostolia M. Tsimberidou, Erick Campbell, Samuel Urrutia, David S. Hong, Funda Meric-Bernstam, Ying Yuan, Timothy A. Yap. Dynamic changes in monocyte and reticulocyte counts predict mechanism-based anemia development and recovery during ATR inhibitor treatment in phase I/II trials. [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 6181.

Pertuzumab Plus Trastuzumab in Patients With Endometrial Cancer With ERBB2/3 Amplification, Overexpression, or Mutation: Results From the TAPUR Study

PURPOSE

The TAPUR Study is a pragmatic basket trial evaluating antitumor activity of commercially available targeted agents in patients with advanced cancers harboring potentially actionable genomic alterations. Data from a cohort of patients with endometrial cancer (EC) with ERBB2 or ERBB3 (ERBB2/3) amplification, overexpression, or mutation treated with pertuzumab plus trastuzumab (P + T) are reported.

METHODS

Eligible patients had advanced EC, no standard treatment options, measurable disease (RECIST v1.1), Eastern Cooperative Oncology Group performance status 0-2, adequate organ function, and tumors with ERBB2/3 amplification, overexpression, or mutation. Simon's two-stage design was used with a primary end point of disease control (DC), defined as objective response (OR) or stable disease (SD) of at least 16 weeks (SD16+) duration. Secondary end points include safety, duration of response, duration of SD, progression-free survival (PFS), and overall survival (OS).

RESULTS

Twenty-eight patients were enrolled from March 2017 to November 2019; all patients were evaluable for efficacy and toxicity. Seventeen patients had tumors with ERBB2/3 amplification and/or overexpression, eight with both ERBB2 amplification and ERBB2/3 mutations, and three with only ERBB2 mutations. Ten patients had DC (two partial response and eight SD16+); all 10 had ERBB2 amplification, and 6 of the 10 patients with DC had >1 ERBB2/3 alteration. DC and OR rates were 37% (95% CI, 21 to 50) and 7% (95% CI, 1 to 24), respectively; the median PFS and median OS were 16 weeks (95% CI, 10-28) and 61 weeks (95% CI, 24-105), respectively. One patient experienced a grade 3 serious adverse event (muscle weakness) at least possibly related to P + T.

CONCLUSION

P + T has antitumor activity in heavily pretreated patients with EC with ERBB2 amplification and warrants additional study.

Precision Oncology: Evolving Clinical Trials across Tumor Types

Advances in molecular technologies and targeted therapeutics have accelerated the implementation of precision oncology, resulting in improved clinical outcomes in selected patients. The use of next-generation sequencing and assessments of immune and other biomarkers helps optimize patient treatment selection. In this review, selected precision oncology trials including the IMPACT, SHIVA, IMPACT2, NCI-MPACT, TAPUR, DRUP, and NCI-MATCH studies are summarized, and their challenges and opportunities are discussed. Brief summaries of the new ComboMATCH, MyeloMATCH, and iMATCH studies, which follow the example of NCI-MATCH, are also included. Despite the progress made, precision oncology is inaccessible to many patients with cancer. Some patients' tumors may not respond to these treatments, owing to the complexity of carcinogenesis, the use of ineffective therapies, or unknown mechanisms of tumor resistance to treatment. The implementation of artificial intelligence, machine learning, and bioinformatic analyses of complex multi-omic data may improve the accuracy of tumor characterization, and if used strategically with caution, may accelerate the implementation of precision medicine. Clinical trials in precision oncology continue to evolve, improving outcomes and expediting the identification of curative strategies for patients with cancer. Despite the existing challenges, significant progress has been made in the past twenty years, demonstrating the benefit of precision oncology in many patients with advanced cancer.

Multicenter Phase II Trial of the WEE1 Inhibitor Adavosertib in Refractory Solid Tumors Harboring CCNE1 Amplification

PURPOSE

Preclinical cancer models harboring CCNE1 amplification were more sensitive to adavosertib treatment, a WEE1 kinase inhibitor, than models without amplification. Thus, we conducted this phase II study to assess the antitumor activity of adavosertib in patients with CCNE1-amplified, advanced refractory solid tumors.

PATIENTS AND METHODS

Patients aged ≥ 18 years with measurable disease and refractory solid tumors harboring CCNE1 amplification, an Eastern Cooperative Oncology Group performance status of 0-1, and adequate organ function were studied. Patients received 300 mg of adavosertib once daily on days 1 through 5 and 8 through 12 of a 21-day cycle. The trial followed Bayesian optimal phase II design. The primary end point was objective response rate (ORR).

RESULTS

Thirty patients were enrolled. The median follow-up duration was 9.9 months. Eight patients had partial responses (PRs), and three had stable disease (SD) ≥ 6 months, with an ORR of 27% (95% CI, 12 to 46), a SD ≥ 6 months/PR rate of 37% (95% CI, 20 to 56), a median progression-free survival duration of 4.1 months (95% CI, 1.8 to 6.4), and a median overall survival duration of 9.9 months (95% CI, 4.8 to 15). Fourteen patients with epithelial ovarian cancer showed an ORR of 36% (95% CI, 13 to 65) and SD ≥ 6 months/PR of 57% (95% CI, 29 to 82), a median progression-free survival duration of 6.3 months (95% CI, 2.4 to 10.2), and a median overall survival duration of 14.9 months (95% CI, 8.9 to 20.9). Common treatment-related toxicities were GI, hematologic toxicities, and fatigue.

CONCLUSION

Adavosertib monotherapy demonstrates a manageable toxicity profile and promising clinical activity in refractory solid tumors harboring CCNE1 amplification, especially in epithelial ovarian cancer. Further study of adavosertib, alone or in combination with other therapeutic agents, in CCNE1-amplified epithelial ovarian cancer is warranted.

Predictors of Oncologic Outcome in Patients Receiving Phase I Investigational Therapy for Recurrent or Metastatic Cervical Cancer

Introduction

We aimed to identify clinical, pathologic, and treatment factors that are predictive of response and survival in patients with cervical cancer referred to phase I clinical trials.

Methods

Patients with cervical cancer who received at least one dose of a phase I investigational agent at our institution between 2014 and 2022 were included. The log-rank test was used to analyze differences in progression-free survival (PFS) and overall survival (OS), and multivariable regression analysis was performed.

Results

We included 65 patients with a median age of 41 years (range, 20-74), 3 prior therapies (range, 1-7), and 67.7% squamous carcinoma. The rate of distant metastasis at trial entry was 84.6%. The most common molecular alterations included PIK3CA (46.5%), PD-L1+ (46.2%), EPH (30.0%), and CREBBP (23.1%); 23.1% had received a prior checkpoint inhibitor. Phase I trials were for immunotherapy (58.5%) or targeted therapy (41.5%). The rate of biomarker matching was 21.5%. For all patients, median PFS was 3.6 months (95% CI, 2.0-5.2) and OS was 9.3 months (95% CI, 7.0-10.6). Factors at study entry associated with worse survival were presence of bone metastasis (PFS 1.6 vs 4.4 months: hazard ratio [HR], 2.8; p = 0.001; OS 3.8 vs 10.0 months: HR, 3.9; p < 0.0001) and absolute lymphocyte count below 1000/μL (PFS 1.8 vs 5.2 months: HR, 2.9; p = 0.0004; OS 7.0 vs 10.6 months: HR, 3.2; p = 0.0009). Factors associated only with worse OS were absolute neutrophil count above 4700/μL, hemoglobin below 10.5 g/dL, and smoking status. Grade 3+ treatment-related adverse events were seen in 16.9% of cases.

Conclusion

Bone metastasis and absolute lymphocyte count below normal range at phase I study entry portend poor survival in patients with recurrent or metastatic cervical cancer.

Complex I inhibitor of oxidative phosphorylation in advanced solid tumors and acute myeloid leukemia: phase I trials

Although targeting oxidative phosphorylation (OXPHOS) is a rational anticancer strategy, clinical benefit with OXPHOS inhibitors has yet to be achieved. Here we advanced IACS-010759, a highly potent and selective small-molecule complex I inhibitor, into two dose-escalation phase I trials in patients with relapsed/refractory acute myeloid leukemia (NCT02882321, n = 17) and advanced solid tumors (NCT03291938, n = 23). The primary endpoints were safety, tolerability, maximum tolerated dose and recommended phase 2 dose (RP2D) of IACS-010759. The PK, PD, and preliminary antitumor activities of IACS-010759 in patients were also evaluated as secondary endpoints in both clinical trials. IACS-010759 had a narrow therapeutic index with emergent dose-limiting toxicities, including elevated blood lactate and neurotoxicity, which obstructed efforts to maintain target exposure. Consequently no RP2D was established, only modest target inhibition and limited antitumor activity were observed at tolerated doses, and both trials were discontinued. Reverse translational studies in mice demonstrated that IACS-010759 induced behavioral and physiological changes indicative of peripheral neuropathy, which were minimized with the coadministration of a histone deacetylase 6 inhibitor. Additional studies are needed to elucidate the association between OXPHOS inhibition and neurotoxicity, and caution is warranted in the continued development of complex I inhibitors as antitumor agents.

Clinical trial design in the era of precision medicine

Recent rapid biotechnological breakthroughs have led to the identification of complex and unique molecular features that drive malignancies. Precision medicine has exploited next-generation sequencing and matched targeted therapy/immunotherapy deployment to successfully transform the outlook for several fatal cancers. Tumor and liquid biopsy genomic profiling and transcriptomic, immunomic, and proteomic interrogation can now all be leveraged to optimize therapy. Multiple new trial designs, including basket and umbrella trials, master platform trials, and N-of-1 patient-centric studies, are beginning to supplant standard phase I, II, and III protocols, allowing for accelerated drug evaluation and approval and molecular-based individualized treatment. Furthermore, real-world data, as well as exploitation of digital apps and structured observational registries, and the utilization of machine learning and/or artificial intelligence, may further accelerate knowledge acquisition. Overall, clinical trials have evolved, shifting from tumor type-centered to gene-directed and histology-agnostic trials, with innovative adaptive designs and personalized combination treatment strategies tailored to individual biomarker profiles. Some, but not all, novel trials now demonstrate that matched therapy correlates with superior outcomes compared to non-matched therapy across tumor types and in specific cancers. To further improve the precision medicine paradigm, the strategy of matching drugs to patients based on molecular features should be implemented earlier in the disease course, and cancers should have comprehensive multi-omic (genomics, transcriptomics, proteomics, immunomic) tumor profiling. To overcome cancer complexity, moving from drug-centric to patient-centric individualized combination therapy is critical. This review focuses on the design, advantages, limitations, and challenges of a spectrum of clinical trial designs in the era of precision oncology.

Longitudinal Monitoring of Circulating Tumor DNA to Predict Treatment Outcomes in Advanced Cancers

PURPOSE

The response to cancer therapies is typically assessed with radiologic imaging 6-10 weeks after treatment initiation. Circulating tumor DNA (ctDNA), however, has a short half-life, and dynamic changes in ctDNA quantity may allow for earlier assessment of the therapeutic response.

METHODS

Patients with advanced solid tumors referred to the Department of Investigational Cancer Therapeutics at The University of Texas MD Anderson Cancer Center were invited to participate in a liquid biopsy protocol for which serial blood samples were collected before, during, and after systemic therapy. We isolated ctDNA from serially collected plasma samples at baseline, mid-treatment, and first restaging. Genomically informed droplet digital polymerase chain reaction (ddPCR) was performed, and ctDNA quantities were reported as aggregate variant allele frequencies for all detected molecular aberrations.

RESULTS

We included 204 patients receiving 260 systemic therapies. The ctDNA detection rate was higher in progressors (patients with progressive disease) compared with nonprogressors (patients with stable disease, partial responses, or complete responses) at all time points (P < .009). Moreover, ctDNA detection was associated with a shorter median time-to-treatment failure (P ≤ .001). Positive delta and slope values for changes in ctDNA quantity were more frequent in progressors (P ≤ .03 and P < .001, respectively) and were associated with a shorter median time-to-treatment failure (P ≤ .014 and P < .001, respectively). Increasing ctDNA quantity was predictive of clinical and/or radiologic progressive disease in 73% of patients (median lead time, 23 days).

CONCLUSION

Detection of ctDNA and early dynamic changes in its quantity can predict the clinical outcomes of systemic therapies in patients with advanced solid tumors.

Supportive care for the prevention of nausea, vomiting and anorexia in a phase 1B study of selinexor in advanced cancer patients: an exploratory study

INTRODUCTION

Clinical observations of cancer patients treated with selinexor have reported high incidence of nausea and anorexia. The study objective was to investigate the adoption of prophylactic olanzapine for the prevention of nausea, vomiting and anorexia in cancer patients receiving selinexor and standard chemotherapy.

METHODS

We retrospectively reviewed supportive care interventions in patients receiving selinexor and recorded frequency of adverse events (NCI-CTAE). Association between categorical variables were analyzed using Fisher's exact tests; repeated measures analysis was performed to assess weight changes over time.

RESULTS

Of 124 evaluable patients, 83 (66.9%) were female, 93 were white (75.0%), and the most common cancer was ovarian (N = 30, 24.2%). One hundred and four patients (83.9%) received olanzapine, of which 93 (89.4%) were prophylactically treated, the majority (86.5%) receiving low 2.5 mg daily dose. Other anti-emetics included ondansetron in 90 patients (72.6%), dexamethasone prescribed in 50 patients (40.3%) and metoclopramide in 49 patients (39.5%), while aprepitant/fosaprepitant (N = 2, 1.6%) were prescribed infrequently. Cancer patients receiving prophylactic olanzapine (N = 93) compared to patients who never received olanzapine (N = 20) had more Grade 1 + anorexia (31.2% vs 20.0%), less nausea (53.8% vs 70.0%), less vomiting (33.3% vs 40.0%), and increased hyperglycemia (29.0% vs 10.0%), but differences were non-statistically significant. In addition, there was minimal weight loss over time in both groups and no statistically significant differences in weight loss between groups.

CONCLUSION

Prophylactic olanzapine decreased nausea, vomiting and maintained weight over 3 months but did not prevent anorexia in patients receiving selinexor and chemotherapy. Low dose olanzapine was well tolerated but associated with hyperglycemia.

PIK3CA mutations in plasma circulating tumor DNA predict survival and treatment outcomes in patients with advanced cancers

Background

Oncogenic mutations in PIK3CA are prevalent in diverse cancers and can be targeted with inhibitors of the phosphoinositide-3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR) pathway. Analysis of circulating tumor DNA (ctDNA) provides a minimally invasive approach to detect clinically actionable PIK3CA mutations.

Patients and methods

We analyzed PIK3CA hotspot mutation frequency by droplet digital PCR (QX 200; BioRad) using 16 ng of unamplified plasma-derived cell-free DNA from 68 patients with advanced solid tumors (breast cancer, n = 41; colorectal cancer, n = 13; other tumor types, n = 14). Results quantified as variant allele frequencies (VAFs) were compared with previous testing of archival tumor tissue and with patient outcomes.

Results

Of 68 patients, 58 (85%) had PIK3CA mutations in tumor tissue and 43 (74%) PIK3CA mutations in ctDNA with an overall concordance of 72% (49/68, κ = 0.38). In a subset analysis, which excluded samples from 26 patients known not to have disease progression at the time of sample collection, we found an overall concordance of 91% (38/42; κ = 0.74). PIK3CA-mutated ctDNA VAF of ≤8.5% (5% trimmed mean) showed a longer median survival compared with patients with a higher VAF (15.9 versus 9.4 months; 95% confidence interval 6.7-17.1 months; P = 0.014). Longitudinal analysis of ctDNA in 18 patients with serial plasma collections (range 2-22 time points, median 5) showed that those with a decrease in PIK3CA VAF had a longer time to treatment failure (TTF) compared with patients with an increase or no change (10.7 versus 2.6 months; P = 0.048).

Conclusions

Detection of PIK3CA mutations in ctDNA is concordant with testing of archival tumor tissue. Low quantity of PIK3CA-mutant ctDNA is associated with longer survival and a decrease in PIK3CA-mutant ctDNA on therapy is associated with longer TTF.

•

Testing for PIK3CA mutations in ctDNA is concordant with testing of tumor tissue.

•

High PIK3CA-mutant abundance in ctDNA was associated with shorter survival.

•

Increasing PIK3CA-mutant abundance in serial blood samples was associated with shorter TTF.

•

Longitudinal monitoring of PIK3CA-mutant ctDNA tracked with cancer clinical course.

Pembrolizumab in Patients with Refractory Cutaneous Squamous Cell Carcinoma: A Phase II Trial

INTRODUCTION

Patients with advanced cutaneous squamous cell carcinoma (CSCC) have a poor prognosis. Blocking the PD-1-PD-L1 axis has shown promising activity in this patient population. We assessed the safety and antitumor activity of PD-1 inhibitor pembrolizumab in patients with refractory advanced CSCC.

METHODS

This was a prespecified subgroup analysis of patients with advanced CSCC who enrolled in an open-label, phase II clinical trial for pembrolizumab in patients with refractory rare cancers during 2016-2018. Patients received pembrolizumab 200 mg intravenously every 21 days until progressive disease, unacceptable adverse event, or completion of 24 months of treatment. The primary endpoint was nonprogression rate (NPR) at 27 weeks; secondary endpoints included safety, objective response rate (ORR) per irRECIST, clinical benefit rate (CBR), progression-free survival, and overall survival.

RESULTS

Twenty patients with refractory CSCC enrolled; 19 were evaluable for efficacy. Median follow-up time was 44.1 months. The NPR at 27 weeks was 37% (95% CI 0.16-0.62). Three patients had a complete response (CR), three had a partial response, and one had stable disease, for an ORR of 32% and a CBR of 37%; median duration of response was 27.3 months. All three patients with a CR remained free of recurrence at the time of writing. Severe treatment-related adverse events (grade ≥ 3) occurred in 10% of patients (2/20). PD-L1 expression was not correlated with response to pembrolizumab.

CONCLUSION

A long-term follow-up confirms pembrolizumab's antitumor activity and safety profile in patients with refractory CSCC. Patients with a CR may experience cure.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT02721732, Registered March 29, 2016.

Abstract CT109: Phase I study of mTORC1-2 inhibitor sapanisertib (TAK-228) in combination with carboplatin plus paclitaxelin patients with advanced solid malignancies and mTOR pathway alterations

Introduction: Pre-clinical models show that the addition of the mTORC1/2 inhibitor sapanisertib (TAK-228) restores sensitivity to platinum chemotherapy and dramatically enhances paclitaxel-induced cancer cell killing. Carboplatin plus paclitaxel is an established therapy in a variety of cancers including non-small cell lung cancer, ovarian cancer and others. This phase 1 study (NCT03430882) assessed the safety and tolerability of sapanisertib in combination with carboplatin plus paclitaxel in patients with advanced solid malignancies enriched with mTOR pathway alterations.

Methods: Eligible patients, enriched for mTOR pathway aberrant tumors by CLIA-certified next-generation sequencing, received increasing sapanisertib doses on day 2-4 of each week at 2mg (Dose level 1; 4 patients), 3mg (Dose level 2; 4 patients) and 4mg (Dose level 3; 4 patients) combined with carboplatin (AUC 5) intravenously every 3 weeks on day 1 of each cycle plus paclitaxel 40mg/m2 (Dose levels 1-3), 60mg/m2 (Dose level 4; 7 patients) on day 1, 8, and 15 of each cycle.

Results: Among the patients enrolled, males were 8/19 (42%), median age was 59 (range: 33-74). Of the 12 patients treated with Dose levels 1-3, 11 patients were evaluable for dose-limiting toxicities (DLTs) and no DLTs were observed. Seven patients were treated in Dose level 4 and among the 6 patients that were evaluable for DLTs, 1 patient had a DLT. Genomic alterations included PI3K/PTEN in 11/19 (58%), NF1 in 2/19 (10.5%), NF2 in 2/19 (10.5%), TSC1 in 1/19 (5%), TSC2 in 1/19 (5%), and EWSR1-POU5F1 fusion in 1/19 (5%). Of 17 patients evaluable for response, disease control rate (CR+PR+SD) was 76.4 % including 2 patients who achieved partial response. Responders were a patient with sarcomatoid renal cell carcinoma harboring EWSR1-POU5F1 fusion, who remains on therapy for more than 18 months. In addition, a patient with castrate resistant prostate cancer who progressed on cabazitaxel but harbors PTEN loss and remained on therapy for 7.3 months. There were no unanticipated toxicities. Grade 3-4 treatment-related adverse events included anemia (4/19; 21%), neutropenia (4/19; 21%), thrombocytopenia (2/19; 10.5%), and transaminitis (1/19; 5%).

Conclusion: Sapanisertib in combination with carboplatin plus paclitaxel demonstrated a manageable safety profile, with preliminary antitumor activity observed in patients with advanced malignancies harboring mTOR pathway alterations.

Citation Format: Omar Alhalabi, Aung Naing, Roman Groisberg, Andrew Hahn, Shizhen Zhang, Samantha C. Berkey, Apostolia M. Tsimberidou, Jordi Rodon, Timothy A. Yap, Shubham Pant, Amishi Y. Shah, Amado Zurita-Saavedra, Nizar Tannir, Funda Meric-Bernstam, Vivek Subbiah. Phase I study of mTORC1-2 inhibitor sapanisertib (TAK-228) in combination with carboplatin plus paclitaxelin patients with advanced solid malignancies and mTOR pathway alterations [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 CT109.

Abstract 974: Phase II trial of the Wee1 inhibitor adavosertib in advanced refractory solid tumors with CCNE1 amplification

Background: Wee1 kinase, which prevents premature mitotic entry by inhibiting cyclin-dependent kinases (CDKs), may be essential when cyclin E1 is overexpressed in order to prevent DNA damage and cell death. In preclinical studies, cancer models harboring CCNE1 amplification are highly sensitive to treatment with adavosertib, a Wee1 kinase inhibitor. A multicenter phase 2 study was conducted to assess the antitumor activity of adavosertib in patients with CCNE1 amplified advanced refractory solid tumors.

Methods: Patients with advanced refractory solid tumors harboring CCNE1 amplification pre-identified in a Clinical Laboratory Improvement Amendments (CLIA)-certified laboratory were eligible. They had refractory disease, on standard options available, or they declined standard-of-care therapy. Eligible patients must be aged ≥ 18 years and had measurable disease per RECIST (Response Evaluation Criteria in Solid Tumors) 1.1, ECOG (Eastern Cooperative Oncology Group) performance status of 0-1, and adequate organ functions. After informed consent, patients received adavosertib 300 mg daily on days 1 to 5 and 8 to 12 of a 21-day cycle. The primary endpoint was objective response rate (ORR). The trial employed Simon's two-stage design.

Results: Between January 22, 2019 and May 20, 2020, 29 patients with 12 tumor types were enrolled on study: ovarian = 14, breast = 3, endometrial = 2; and carcinosarcoma, cholangiocarcinoma, esophageal, gallbladder, germ cell tumor, melanoma, prostate, sarcoma, sarcomatoid and urothelial = 10 (1 each tumor). Median follow-up was 11.7 months. The median line of prior systemic therapy was 4 (range 1-8). Twenty-seven patients were evaluable for response. In these patients, 7 confirmed partial responses (PR) were observed, for an ORR of 25.9% (95% CI 15.1-47.5%). The median progression-free survival was 4.0 months and one-year overall survival was 55%. In 13 patients with measurable high-grade serous ovarian cancer, 5 achieved PR (38.5%) and 8 had stable disease ≥6 months/PR (61.5%). Other PRs were seen in 1 urothelial carcinoma and 1 melanoma. Fifteen patients experienced grade 3 or higher treatment-related adverse events: neutropenia (24%), thrombocytopenia (17%), anemia (14%), nausea (17%), diarrhea (17%) and fatigue (17%). Sixteen patients required dose duction of adavosertib to 250 mg, and 7 further to 200 mg. Biomarker analysis is ongoing to investigate potential biomarkers of response.

Conclusions: Adavosertib monotherapy demonstrates promising clinical activity in patients with refractory solid tumors harboring CCNE1 amplification, especially in high-grade serous ovarian cancer. Further exploration of adavosertib in CCNE1 amplified high grade serous ovarian cancer is warranted.

Citation Format: Siqing Fu, Shuyang Yao, Yuan Yuan, Rebecca A. Previs, Anthony D. Elias, Richard Carvajal, Thomas J. George, Ying Yuan, Yuko Yamamura, Shannon Westin, Yan Xing, Ecaterina E. Ileana Dumbrava, Daniel D. Karp, Sarina A. Piha-Paul, Apostolia M. Tsimberidou, Jordi Rodon, Naoko Takebe, Charles Kunos, Karen Lu, Khanda Keyomarsi, Funda Meric-Bernstam. Phase II trial of the Wee1 inhibitor adavosertib in advanced refractory solid tumors with CCNE1 amplification [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 974.

Phase 2 study of pembrolizumab in patients with advanced rare cancers

Background

Patients with advanced rare cancers have poor prognosis and few treatment options. As immunotherapy is effective across multiple cancer types, we aimed to assess pembrolizumab (programmed cell death 1 (PD-1) inhibitor) in patients with advanced rare cancers.

Methods

In this open-label, phase 2 trial, patients with advanced rare cancers whose tumors had progressed on standard therapies, if available, within the previous 6 months were enrolled in nine tumor-specific cohorts and a 10th cohort for other rare histologies. Pembrolizumab 200 mg was administered intravenously every 21 days. The primary endpoint was non-progression rate (NPR) at 27 weeks; secondary endpoints were safety and tolerability, objective response rate (ORR), and clinical benefit rate (CBR).

Results

A total of 127 patients treated between August 15, 2016 and July 27, 2018 were included in this analysis. At the time of data cut-off, the NPR at 27 weeks was 28% (95% CI, 19% to 37%). A confirmed objective response (OR) was seen in 15 of 110 (14%) evaluable patients (complete response in one and partial response in 14). CBR, defined as the percentage of patients with an OR or stable disease ≥4 months, was 38% (n=42). Treatment was ongoing in 11 of 15 patients with OR at last follow-up. In the cohort with squamous cell carcinoma (SCC) of the skin, the NPR at 27 weeks was 36%, ORR 31%, and CBR 38%. In patients with adrenocortical carcinoma (ACC), NPR at 27 weeks was 31%, ORR 15%, and CBR 54%. In the patients with carcinoma of unknown primary (CUP), NPR at 27 weeks was 33%, ORR 23%, and CBR 54%. In the paraganglioma–pheochromocytoma cohort, NPR at 27 weeks was 43%, ORR 0%, and CBR 75%. Treatment-related adverse events (TRAEs) occurred in 66 of 127 (52%) patients, and 12 (9%) had grade ≥3 TRAEs. The most common TRAEs were fatigue (n=25) and rash (n=17). There were six deaths, all of which were unrelated to the study drug.

Conclusions

The favorable toxicity profile and antitumor activity seen in patients with SCC of skin, ACC, CUP, and paraganglioma–pheochromocytoma supports further evaluation of pembrolizumab in this patient population.

Trial registration number

NCT02721732

Preclinical Development and First-in-Human Study of KA2507, a Selective and Potent Inhibitor of Histone Deacetylase 6, for Patients with Refractory Solid Tumors

PURPOSE

Inhibition of histone deacetylase 6 (HDAC6) is predicted to deliver both direct antitumor activity and modulation of the antitumor immune response. This study describes the development of a novel HDAC6 inhibitor.

PATIENTS AND METHODS

KA2507 was characterized in HDAC biochemical and cellular target engagement assays and in preclinical efficacy models of melanoma and colorectal cancer. In a phase I study, KA2507 was administered orally using a 3+3 dose-escalation design (NCT03008018).

RESULTS

KA2507 is a potent and selective inhibitor of HDAC6 (biochemical IC₅₀ = 2.5 nmol/L). Preclinical models demonstrated antitumor efficacy in syngeneic tumor-bearing mice, with translational studies highlighting modulation of the antitumor immune response. Twenty patients were treated in a phase I study. KA2507 was well tolerated; dose-limiting toxicity was not observed up to the maximum dose administered. Pharmacokinetic profiling supported twice-daily oral dosing. Pharmacodynamic analysis demonstrated selective HDAC6 target engagement in peripheral blood cells, free from off-target class I HDAC activity. Stable disease was the best clinical response (7 patients). Three of these patients (adenoid cystic carcinoma, n = 2; rectal adenocarcinoma, n = 1) had prolonged disease stabilization that lasted for 16.4, 12.6, and 9.0 months, respectively.

CONCLUSIONS

KA2507 is a potent and selective inhibitor of HDAC6 showing antitumor efficacy and immune modulatory effects in preclinical models. In a phase I study, KA2507 showed selective target engagement, no significant toxicities, and prolonged disease stabilization in a subset of patients. Further clinical studies of KA2507 are warranted, as a single agent or, preferably, combined with other immuno-oncology drugs.

Patient-Reported Out-of-Pocket Costs and Financial Toxicity During Early-Phase Oncology Clinical Trials

BACKGROUND

Clinical trials are an important therapeutic option for patients with cancer. Although financial burden in cancer treatment is well documented, the financial burden associated with clinical trials is not well understood.

PATIENTS AND METHODS

We conducted a survey regarding economic burden and financial toxicity in patients with cancer enrolled in phase I clinical trials for >1 month. Financial toxicity score was assessed using the Comprehensive Score for Financial Toxicity survey. Patients also reported monthly out-of-pocket (OOP) costs.

RESULTS

Two hundred and thirteen patients completed the survey (72% non-Hispanic White; 45% with annual income ≤$60,000; 50% lived >300 miles from the clinic; 37% required air travel). Forty-eight percent of patients had monthly OOP costs of at least $1,000. Fifty-five percent and 64% of patients reported unanticipated medical and nonmedical expenses, respectively. Worse financial toxicity was associated with yearly household income <$60,000 (odds ratio [OR]: 2.7; p = .008), having unanticipated medical costs (OR: 3.2; p = .024), and living >100 miles away from the clinical trial hospital (OR: 2.3; p = .043). Non-White or Hispanic patients (OR: 2.5; p = .011) and patients who were unemployed or not working outside the home (OR: 2.5; p = .016) were more likely to report high unanticipated medical costs.

CONCLUSION

Among patients with cancer participating in clinical trials, economic burden is high, and most of patients' OOP costs were nonmedical costs. Financial toxicity is disproportionally higher in patients with lower income and those who travel farther, and unexpected medical costs were more common among non-White or Hispanic patients. OOP costs can be substantial and are often unexpected for patients.

IMPLICATIONS FOR PRACTICE

The financial burden of cancer treatment is well documented, but there are limited data regarding the financial burden associated with cancer clinical trials. This study surveyed 213 patients enrolled in early-phase clinical trials. Monthly out-of-pocket costs were at least $1000 for nearly half of patients. Worse financial toxicity was associated with income <$60,000 and living farther away from the hospital. Racial/ethnic minorities had higher rates of unanticipated medical costs. These data help to quantify the high financial burden for patients and may reveal a cause of disparities in clinical trial enrollment for underrepresented populations.

Overview of Ocular Side Effects of Selinexor

BACKGROUND

The aim of this review is to elucidate the type and frequency of ocular adverse events associated with selinexor with a goal to quantify the occurrence of these events in our investigator-initiated trial.

METHODS

We retrospectively reviewed medical records of 174 patients treated with at least one dose of selinexor in combination with multiple standard chemotherapy or immunotherapy agents between July 2015 and July 2020 at a comprehensive cancer center in the U.S. All reported ocular adverse events were assessed.

RESULTS

A total of 174 patient medical records were reviewed. All patients received at least one dose of selinexor in combination with multiple standard chemotherapy or immunotherapy agents in our cohort of patients with advanced malignancies. A total of 34 (19.54%) patients experienced 37 ocular adverse events. The most frequently reported ocular symptom was blurred vision, which was reported in 22 (12.64%) patients. The most frequently reported treatment-related adverse event was dry eye syndrome reported in 21 (12.1%) patients, and 19 (10.9%) of them were diagnosed with mild dry eye. The second most common treatment-related adverse event was the progression of age-related nuclear sclerosis (cataract) reported in 7 (4.0%) patients. None of the ocular adverse events required therapy discontinuation.

CONCLUSION

Our findings highlight that ocular adverse events associated with oral selinexor were mild. The most frequently reported ocular treatment-related adverse events were mild dry eye and progression of age-related nuclear sclerosis. None of the ocular adverse events required therapy discontinuation.

IMPLICATIONS FOR PRACTICE

Patients receiving selinexor in combination with multiple standard chemotherapy or immunotherapy agents were reviewed, with a total of 34 patients experiencing 37 ocular adverse events. Findings highlight that ocular adverse events associated with oral selinexor were mild. The most frequently reported ocular treatment-related adverse events were mild dry eye and progression of age-related nuclear sclerosis. None of the ocular adverse events required therapy discontinuation.

Phase I Study of Everolimus, Letrozole, and Trastuzumab in Patients with Hormone Receptor-positive Metastatic Breast Cancer or Other Solid Tumors

PURPOSE

Doublets of everolimus with letrozole or trastuzumab have demonstrated activity against HER2-positive breast cancer, suggesting that the triple combination can have synergistic anticancer activity.

PATIENTS AND METHODS

This first-in-human dose-escalation study (NCT02152943) enrolled patients with hormone receptor- positive, HER2-positive (defined by amplification, overexpression, or mutation) treatment-refractory advanced cancers to receive escalating doses (3+3 design) of daily oral letrozole (days 1-21), daily oral everolimus (days 1-21), and intravenous trastuzumab (day 1) every 21 days to determine dose-limiting toxicities (DLT) and MTD or recommended phase II dose (RP2D).

RESULTS

A total of 32 patients with hormone receptor-positive, HER2-positive (amplification, n = 27; overexpression, n = 1; and mutation, n = 4) advanced breast cancer (n = 26) or other cancers (n = 6) were enrolled. The most frequent grade ≥3 adverse events included hyperglycemia (n = 4), anemia (n = 3), thrombocytopenia (n = 2), and mucositis (n = 2). DLTs included grade 3 mucositis and grade 4 neutropenia, and trastuzumab given as an 8 mg/kg loading dose on day 1 of cycle 1 followed by a 6 mg/kg maintenance dose on day 1 of subsequent cycles plus 10 mg everolimus daily and 2.5 mg letrozole daily every 21 days was declared as RP2D. Five patients with breast cancer (four with HER2 amplification and one with HER2 mutation) had partial responses. HER2 amplification in circulating cell-free DNA at baseline was associated with shorter progression-free and overall survival durations (P < 0.05).

CONCLUSIONS

Everolimus, letrozole, and trastuzumab have a favorable safety profile and elicit encouraging signals of anticancer activity in patients with heavily pretreated hormone receptor- and HER2-positive advanced cancers.

Abstract PO-208: Patient-reported out-of-pocket costs and financial toxicity during early- phase oncology clinical trials

Background Clinical trials are an important therapeutic option for cancer patients (pts). Although financial burden in cancer treatment is well-documented, the financial burden associated with clinical trials is not well understood, especially for pts with lower income. Methods We conducted a survey regarding economic burden and financial toxicity in cancer pts who had been on Phase I clinical trials for ≥1 month. Financial Toxicity Score (FTS) was assessed using the validated COmprehensive Score for Financial Toxicity (COST) survey (scale 0-44, lower scores indicate worse toxicity). Pts also reported monthly out-of-pocket (OOP) medical and non-medical expenses. We applied multivariable logistic regression to analyze risk of financial toxicity, and unanticipated expenses. Results Early-phase clinical trial pts (N=213, median age = 59y; 59% female; 74% White, 45% w/ annual income ≤$60K; 54% had employer sponsored insurance; 37% had Medicare; 50% lived &gt;300 miles from the clinic; 37% required air travel) had a median FTS of 20, with interquartile range of 12. Median monthly OOP costs for non-medical expenses was $1075, and for medical expenses was $475. Median total monthly OOP costs was $1750. 55% and 64% of pts reported that actual medical and non-medical expenses were higher than expected, respectively. Worse financial toxicity (≤ median FTS) in pts was associated with yearly household income &lt;$60K (OR: 2.7, P=0.008), having medical costs higher than expected (OR: 3.2, P=0.024), participation on ≥1 Phase I clinical trial prior to their current trial (OR: 2.2, P=0.028), and living &gt;100 miles away from the clinical trials hospital (OR: 2.3, P=0.043). 29% of pts received partial/full reimbursement of clinical trial-related travel costs from study sponsor/other/insurance. Racial/ethnic minority (OR: 2.6, P=0.008) and pts who were unemployed or not working outside the home (OR: 2.4, P=0.023) were more likely to report that actual medical costs were much higher than expected. 53% of pts used savings and 19% borrowed money from friends/family or had a personal fundraiser to pay for treatment. Conclusions Among cancer pts participating on clinical trials, economic burden is high, and most of pts’ OOP costs were on non- medical expenses. Financial toxicity is disproportionally higher in pts with lower income and those who travel farther, and unexpected medical costs were more common among minorities. OOP costs can be substantial and are often unexpected for pts. Future work should focus on methods to reduce disparities in clinical trial participation, including the role of reimbursement of trial-related expenses.

Citation Format: Ryan W. Huey, Goldy C. George, Penny Phillips, Revenda White, Filip Janku, Daniel D. Karp, Aung Naing, Sarina Piha-Paul, Vivek Subbiah, Apostolia M. Tsimberidou, Shubham Pant, Timothy A. Yap, Jordi Rodon, Funda Meric-Bernstam, Ya-Chen Tina Shih, David S. Hong. Patient-reported out-of-pocket costs and financial toxicity during early- phase oncology clinical trials [abstract]. In: Proceedings of the AACR Virtual Conference: Thirteenth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2020 Oct 2-4. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(12 Suppl):Abstract nr PO-208.

Dose-escalation study of vemurafenib with sorafenib or crizotinib in patients with BRAF-mutated advanced cancers

BACKGROUND

BRAF inhibitors are effective in melanoma and other cancers with BRAF mutations; however, patients ultimately develop therapeutic resistance through the activation of alternative signaling pathways such as RAF/RAS or MET. The authors hypothesized that combining the BRAF inhibitor vemurafenib with either the multikinase inhibitor sorafenib or the MET inhibitor crizotinib could overcome therapeutic resistance.

METHODS

Patients with advanced cancers and BRAF mutations were enrolled in a dose-escalation study (3 + 3 design) to determine the maximum tolerated dose (MTD) and the dose-limiting toxicities (DLTs) of vemurafenib with sorafenib (VS) or vemurafenib with crizotinib (VC).

RESULTS

In total, 38 patients (VS, n = 24; VC, n = 14) were enrolled, and melanoma was the most represented tumor type (VS, 38%; VC, 64%). In the VS arm, vemurafenib 720 mg twice daily and sorafenib 400 mg am/200 mg pm were identified as the MTDs, DLTs included grade 3 rash (n = 2) and grade 3 hypertension, and partial responses were reported in 5 patients (21%), including 2 with ovarian cancer who had received previous treatment with BRAF, MEK, or ERK inhibitors. In the VC arm, vemurafenib 720 mg twice daily and crizotinib 250 mg daily were identified as the MTDs, DLTs included grade 3 rash (n = 2), and partial responses were reported in 4 patients (29%; melanoma, n = 3; lung adenocarcinoma, n = 1) who had received previous treatment with BRAF, MEK, and/or ERK inhibitors. Optional longitudinal collection of plasma to assess dynamic changes in circulating tumor DNA demonstrated the elimination of BRAF-mutant DNA from plasma during therapy (P = .005).

CONCLUSIONS

Vemurafenib combined with sorafenib or crizotinib was well tolerated with encouraging activity, including among patients who previously received treatment with BRAF, MEK, or ERK inhibitors.

Evaluating the psychometric properties of the Immunotherapy module of the MD Anderson Symptom Inventory

INTRODUCTION

Immunotherapies have revolutionized the treatment of various cancers, but little is known about their symptomatic toxicity. Assessing these symptoms is best accomplished by asking the patients themselves. However, such reports are subjective and may face challenges as bonafide scientific data. Demonstrating the validity of symptom assessment tools, mainly through the reduction of measurement errors, has the potential to improve patient care if these tools are widely adopted. To that end, we present herein the psychometric properties of the Immunotherapy for Early-Phase Trials module of the MD Anderson Symptom Inventory (MDASI-Immunotherapy EPT) in patients receiving various immunotherapies in early phase trials at a major cancer center.

METHODS

One hundred forty-five patients completed the inventory at baseline, with 85 of them also doing so after 9 weeks of treatment. The mean (±SD) age of the patients was 57.0±12.9 years. Also, 56% of the patients were women, 79% identified as white, and 49% had at least some college education.

RESULTS

The internal consistency reliability of the MDASI-Immunotherapy EPT was excellent, as the Cronbach's alphas for all of its subscales were at least 0.88 (range 0.88-0.95). Known-group validity based on Eastern Cooperative Oncology Group performance status groupings was excellent at 9 weeks after the start of an immunotherapy trial for the MDASI-Immunotherapy EPT severity (effect size, 0.96) and interference (effect size, 0.82) subscales. We found substantial changes in the symptom items difficulty remembering (effect size, -0.85), fever and/or chills (effect size, -0.63), disturbed sleep (effect size, -0.52), diarrhea (effect size, -0.42), and swelling of hands, legs, or feet (effect size, -0.39).

CONCLUSIONS

In conclusion, the MDASI-Immunotherapy EPT is a valid, reliable, and sensitive tool for measuring symptomatic toxicity.

Abstract PR10: PIK3CA mutations in plasma cell-free DNA predict survival and treatment outcomes in patients with advanced cancers

Background: Cell-free DNA (cfDNA) analysis from plasma offers a minimally invasive detection of genomic alterations in personalized cancer therapy. PIK3CA is an actionable gene, which can be targeted with PI3K, AKT and mTOR inhibitors. We hypothesized that common hot-spot PIK3CA mutations can be detected in small amount of plasma cfDNA from patients with progressing advanced cancers.

Methods: PIK3CA mutations (p.H1047R, p.H1047L, p.E542K and p.E545K) were detected by droplet digital PCR (QX 200, BioRad) using 16 ng of unamplified cfDNA from plasma of 68 patients with advanced cancer. Results were compared to the clinical molecular testing of archival tumor tissue performed by next-generation sequencing or PCR during the clinical care.

Results: Of 68 patients (breast cancer, n=41; colorectal cancer, n=13; other tumor types, n=14), 58 patients (85%) had a PIK3CA mutation in the tumor. Testing of plasma cfDNA was in agreement with tumor tissue in 72% of samples (kappa 0.38), sensitivity 67% and specificity 100%. Of 19 falsely negative plasma cfDNA samples, 6 were found to be collected from patients not having disease progression. Additional 9 samples with available cfDNA were retested with increased DNA input (22-247 ng) and 4 had a PIK3CA mutation resulting in agreement for patients with progressing cancers of 85% (kappa 0.61), sensitivity 83% and specificity 100%. Patients with plasma PIK3CA-mutant cfDNA variant-allele frequency (VAF) &lt; 8.5% (&lt;5% trimmed mean) had a longer median survival compared to patients with VAF ≥ 8.5% (68 vs. 40 weeks; P=0.01). Serial collections of plasma cfDNA during systemic therapies were available for 18 patients with a median of 5 time points (range 2-22). Patients with decrease in PIK3CA-mutant VAF in cfDNA compared to increase or no change had a longer time to treatment failure to PI3K pathway-targeted therapies (46 vs. 11 weeks; p=0.04).

Conclusion: Common PIK3CA mutations can be detected in plasma cfDNA with high sensitivity and specificity in patients with progressing cancer if the cfDNA input is sufficient. Low amount of PIK3CA-mutant cfDNA is associated with longer survival. Changes in PIK3CA VAF could be an early surrogate biomarker for time to treatment failure to PI3K-targeted therapies.

This abstract is also being presented as Poster B16.

Citation Format: Ecaterina E. Ileana Dumbrava, Helen J. Huang, Ana Stuckett, Kiran Madwani, Abha Adat, David S. Hong, Sarina A. Piha-Paul, Vivek Subbiah, Daniel D. Karp, Siqing Fu, Aung Naing, Apostolia M. Tsimberidou, Stacey Moulder, Kimberly Koenig, Carlos H. Barcenas, Bryan Kee, David Fogelman, Scott Kopetz, Funda Meric-Bernstam, Filip Janku. PIK3CA mutations in plasma cell-free DNA predict survival and treatment outcomes in patients with advanced cancers [abstract]. In: Proceedings of the AACR Special Conference on Targeting PI3K/mTOR Signaling; 2018 Nov 30-Dec 8; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Res 2020;18(10_Suppl):Abstract nr PR10.

Transcriptomics and solid tumors: The next frontier in precision cancer medicine

Transcriptomics, which encompasses assessments of alternative splicing and alternative polyadenylation, identification of fusion transcripts, explorations of noncoding RNAs, transcript annotation, and discovery of novel transcripts, is a valuable tool for understanding cancer mechanisms and identifying biomarkers. Recent advances in high-throughput technologies have enabled large-scale gene expression profiling. Importantly, RNA expression profiling of tumor tissue has been successfully used to determine clinically actionable molecular alterations. The WINTHER precision medicine clinical trial was the first prospective trial in diverse solid malignancies that assessed both genomics and transcriptomics to match treatments to specific molecular alterations. The use of transcriptome analysis in WINTHER and other trials increased the number of targetable -omic changes compared to genomic profiling alone. Other applications of transcriptomics involve the evaluation of tumor and circulating noncoding RNAs as predictive and prognostic biomarkers, the improvement of risk stratification by the use of prognostic and predictive multigene assays, the identification of fusion transcripts that drive tumors, and an improved understanding of the impact of DNA changes as some genomic alterations are silenced at the RNA level. Finally, RNA sequencing and gene expression analysis have been incorporated into clinical trials to identify markers predicting response to immunotherapy. Many issues regarding the complexity of the analysis, its reproducibility and variability, and the interpretation of the results still need to be addressed. The integration of transcriptomics with genomics, proteomics, epigenetics, and tumor immune profiling will improve biomarker discovery and our understanding of disease mechanisms and, thereby, accelerate the implementation of precision oncology.

Abstract CT151: Phase I study of KA2507, a selective HDAC6 inhibitor, in patients with relapsed or refractory solid tumors

Background: KA2507 is a potent and selective small molecule inhibitor of HDAC6. Inhibition of HDAC6 elicits both cell intrinsic and extrinsic anti-cancer activity. HDAC6 is also involved in the regulation of the co-inhibitory molecule programmed death ligand 1 (PD-L1). We conducted a first-in-human (FIH) study to assess the pharmacokinetics, safety and tolerability of KA2507 monotherapy in patients with advanced cancer with preliminary assessment of any antitumor activity. Methods: In this FIH, dose-escalation phase I study, patients (pts) with advanced metastatic cancer who had failed standard therapy were enrolled. KA2507 was administered orally at escalating doses of 50 mg QD, 100 mg QD, 200 mg QD, 200 mg BID, 400 mg BID, and 800 mg BID (1 cycle = 28 days). A “3+3” design was used. PD assessment was performed measuring changes in acetylated tubulin and histone in peripheral blood cells post dosing. Response was assessed by RECIST 1.1 criteria. (www.clinicaltrials.gov, NCT03008018). Results: Twenty pts with various tumor types commenced treatment from Aug 2017 to Aug 2019. The median age was 56 years (27-78 years) and 13 were males. The most common tumor types were adenoid cystic carcinoma (ACC, n=6) and colorectal cancer (n=4). Seventeen of 20 (85%) pts reported at least one treatment emergent adverse event (AE). Five (25%) pts across all dose cohorts reported treatment related AEs, considered to be at least possibly related to treatment (all Grade 1). No treatment related hematologic toxicities were noted. No dose-limiting toxicity was observed up to the maximum dose level tested. PK analysis demonstrated that the PK parameters of KA2507 were similar across all doses tested and after single and repeated oral dosing, with rapid absorption following oral administration, Tmax ~2 h; t½ ~3 h; dose-proportional exposure; low accumulation. PD assessment demonstrated that the fold-increase in acetylation of tubulin in T-cells increased with exposure (P=0.02), with no significant effect on acetylated histone (P=0.4). Seven (35%) of these heavily pre-treated pts with advanced cancer had stable disease (SD). One pt with ACC had SD and remained on study for 18 cycles, and another pt for 12+ cycles. No objective response was noted. Discussion: KA2507 was well tolerated at all doses tested (up to 800 mg BID) with evidence of selective target engagement at all exposure levels. The dose was not limited by the AEs previously reported in clinical trials of other, less selective HDAC6 inhibitors. A dose of 800 mg BID has been identified for further development and is considered the maximum feasible dose, representing a dose that is well tolerated, achieving exposure that is invariably above the biologically active level identified in pre-clinical syngeneic efficacy models, yet not exceeding the human equivalent dose of the NOAEL in GLP-toxicology and maintaining selectivity for HDAC6. A dose expansion cohort to further investigate this dose is planned.

Citation Format: Apostolia M. Tsimberidou, Philip Beer, Jennifer Bendall, James Dow, Justine King, Hilary McElwaine-Johnn, Ignacio I. Wistuba. Phase I study of KA2507, a selective HDAC6 inhibitor, in patients with relapsed or refractory solid tumors [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 CT151.

Abstract 3172: Evaluation of cytotoxic T cell infiltration and clinical benefit from PD-L1 checkpoint inhibition among PIK3CA mutant microsatellite stable (MSS) metastatic adenocarcinoma patients

Background: Immunotherapy has produced durable responses in advanced cancers with microsatellite instability. However, response rates remain very low for microsatellite stable (MSS) adenocarcinomas, and biomarkers predictive of response are urgently needed. PI3K pathway alterations are known to modulate anti-tumor immune microenvironment. We previously reported increased cytotoxic T cell infiltration and greater clinical benefit from immunotherapy among PIK3CA mutant MSS colorectal cancer patients as compared to PIK3CA wild-type patients. Here, we investigated the immune repertoire and treatment outcomes with anti-PD-L1 checkpoint inhibitors in PIK3CA mutant MSS metastatic adenocarcinoma patients.

Methods: We retrospectively identified metastatic adenocarcinoma patients treated with anti-PD-L1 antibody either as monotherapy or in combination with anti-PD-1 antibody in early phase clinical trials at the MD Anderson Center for Targeted Therapy. Molecular profiling was performed on archived primary or metastatic tumor tissue using CLIA certified targeted next generation sequencing (FoundationOne or Oncomine). PIK3CA mutations were annotated for functional significance by the Precision Oncology Decision Support Team. Density of cytotoxic T cells was determined using immunohistochemistry (IHC) on biopsy or resection specimens. Microsatellite status was assessed using IHC or polymerase chain reaction. Median time to treatment failure (TTF) was estimated using Kaplan and Meier method. Groups were compared using Fischer's exact, Student's T test or Log-rank test, as appropriate.

Results: Twenty-seven patients with MSS metastatic adenocarcinoma (female, 20; male, 7) from 12 different sites were treated with anti-PD-L1 antibody. Breast, colon and esophageal cancers were the most common cancers with 7, 5 and 3 patients, respectively. Activating PIK3CA mutations were present in 7/27 (26%) patients (H1047R, 3; E545K, 2; E542K, 1; co-occuring R88Q and K111N, 1). Patients with activating PIK3CA mutations had trend towards longer median TTF as compared to PIK3CA wild-type patients (6.6 vs. 3.1 months, P=0.1). Similarly, 3/7 (42.9%) patients with activating PIK3CA mutations had stable disease (SD) &gt; 6 months as compared to 2/20 (10%) patients with wild type PIK3CA (P=0.09). CD8 densities were available for 8 patients (5 PIK3CA mutant, 3 PIK3CA wild). Among PIK3CA mutant patients, mean CD8 density was higher in patients who had SD &gt; 6 months as compared to those who did not (630.3 vs 305.1 cells/mm3; P=0.06).

Conclusion: Activating PIK3CA mutations are enriched among MSS metastatic adenocarcinoma patients with prolonged SD (&gt; 6 months) on anti-PD-L1 treatment. PIK3CA mutant patients with prolonged SD have higher CD8 densities, possibly due to high-affinity neopeptide-HLA interactions. Larger studies to validate our observations are warranted, including assessment of neopeptide load and HLA types, which may help identify an immunotherapy sensitive subset of PIK3CA mutant MSS adenocarcinoma.

Citation Format: Maliha Nusrat, Coya Tapia, S. Greg Call, David S. Hong, Sarina A. Piha-Paul, Vivek Subbiah, Jordi Rodon, Apostolia M. Tsimberidou, Abha Adat, Yan Wang, Funda Meric-Bernstam, Michael J. Overman, Scott Kopetz, Filip Janku. Evaluation of cytotoxic T cell infiltration and clinical benefit from PD-L1 checkpoint inhibition among PIK3CA mutant microsatellite stable (MSS) metastatic adenocarcinoma patients [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 3172.

Clinical and Economic Value of Genetic Sequencing for Personalized Therapy in Non-small-cell Lung Cancer

Two recent studies examining the clinical and economic value of next-generation sequencing (NGS)-based diagnostic testing (multi-gene panel examining ≥ 30 genes) for non-small-cell lung cancer therapy compared with single gene ALK, EGFR testing to select therapy demonstrated statistically insignificant improvement in population-level overall survival and only a moderate incremental cost-effectiveness ratio associated with the NGS testing approach. The data, however, revealed a key practice gap: many patients with actionable mutations did not receive targeted therapies. This gap is attributed, in part, to limitations in the availability and interpretation of NGS results, sample processing constraints, limited access to targeted therapies, and lagging awareness of the rapidly evolving field of personalized medicine, all of which result in "clinical inertia," (ie, suboptimal use of targeted therapy against an actionable driver alteration identified by NGS testing). Additional analysis estimated that cost-effectiveness would improve significantly if a higher percentage of patients received testing and if all patients who were eligible for targeted therapies received them. Strategies to address implementation barriers will help to realize the full value of NGS testing in cancer care.

Review of precision cancer medicine: Evolution of the treatment paradigm

In recent years, biotechnological breakthroughs have led to identification of complex and unique biologic features associated with carcinogenesis. Tumor and cell-free DNA profiling, immune markers, and proteomic and RNA analyses are used to identify these characteristics for optimization of anticancer therapy in individual patients. Consequently, clinical trials have evolved, shifting from tumor type-centered to gene-directed, histology-agnostic, with innovative adaptive design tailored to biomarker profiling with the goal to improve treatment outcomes. A plethora of precision medicine trials have been conducted. The majority of these trials demonstrated that matched therapy is associated with superior outcomes compared to non-matched therapy across tumor types and in specific cancers. To improve the implementation of precision medicine, this approach should be used early in the course of the disease, and patients should have complete tumor profiling and access to effective matched therapy. To overcome the complexity of tumor biology, clinical trials with combinations of gene-targeted therapy with immune-targeted approaches (e.g., checkpoint blockade, personalized vaccines and/or chimeric antigen receptor T-cells), hormonal therapy, chemotherapy and/or novel agents should be considered. These studies should target dynamic changes in tumor biologic abnormalities, eliminating minimal residual disease, and eradicating significant subclones that confer resistance to treatment. Mining and expansion of real-world data, facilitated by the use of advanced computer data processing capabilities, may contribute to validation of information to predict new applications for medicines. In this review, we summarize the clinical trials and discuss challenges and opportunities to accelerate the implementation of precision oncology.

Abstract P1-19-18: Everolimus, letrozole and trastuzumab in hormone receptor-positive, HER2-positive/amplified or mutant metastatic cancer: Evaluating synergy and overcoming resistance

Background: Combinations of HER2 and aromatase or mTOR inhibitors demonstrated activity in the clinical setting. We hypothesized that the triple combination of HER2 targeted therapy, aromatase and mTOR inhibitor has increased anticancer activity.

Methods: We designed a 3+3 dose escalation phase I study of the aromatase inhibitor letrozole 2.5mg PO daily, mTOR inhibitor everolimus 2.5-10mg PO daily and HER2 antibody trastuzumab 4-8mg loading dose followed by 2-4mg maintenance dose IV on day 1 of 21-day cycle in patients with hormone-receptor positive, HER2-positive/amplified or mutant advanced cancers (confirmed by immunohistochemistry and/or FISH and/or next-generation sequencing) with preplanned expansion cohort at for patients with metastatic breast cancer to determine maximum tolerated dose (MTD) and/or recommended phase 2 dose (RP2D), dose limiting toxicities (DLT), overall safety and response (NCT02152943).

Results: A total of 32 patients (men, 1; women, 31; HER2 amplification, 28; HER2 mutation, 4; breast cancer, 26; other cancers, 6), median age 55.5 years, median of 5 prior therapies (including letrozole [13] or other aromatase inhibitor [10]; everolimus [3]; trastuzumab [25] or other HER2 targeted therapy [2]) were enrolled in the planned 6 dose levels. The MTD has not been reached and letrozole 2.5mg PO daily, everolimus 10mg PO daily and trastuzumab 8mg loading dose followed by 4mg maintenance dose IV on day 1 of 21-day cycle was declared as RP2D. DLTs included grade 3 (G3) mucositis (1 patient) at dose level 3, and G3 thrombocytopenia, neutropenia (1 patient) at dose level 4. Other G3 or G4 treatment-related toxicities included G4 hyperglycemia in 1 patient, G3 hyperglycemia in 3 patients, G4 anemia in 1 patient, G3 anemia in 2 patients, G3 thrombocytopenia in 1 patient, G3 transaminitis in 1 patient, G3 mucositis in 1 patient and G3 headache in 1 patient. Of 32 patients, 5 (16%) had a partial response (all with heavily-pretreated breast cancer with HER2 amplification [4] or HER2A775_G776insYVMA mutation [1]), 23 (72%) stable disease (SD) including 5 (16%) patients with SD &gt; 12 months (all with heavily-pretreated breast cancer) and 4 (13%) progressed. The median change in size of target lesions per RECIST 1.1. was -5% (-91% to +47%). Median time to treatment failure (TTF) was 4.3 months (95% CI 0.0-9.6). A total of 14 patients had serial plasma collection to assess dynamics of circulating tumor DNA and clonal evolution and the data will be presented at the meeting.

Conclusions: The combination of letrozole, everolimus and trastuzumab is well tolerated with encouraging activity in heavily-pretreated patients with HER2-amplified or mutant advanced breast cancer.

Citation Format: Alexej Ballhausen, Jennifer J Wheler, Daniel D Karp, Sarina A Piha-Paul, Siqing Fu, Shubham Pant, Apostolia M Tsimberidou, David S Hong, Vivek Subbiah, Veronica R Holley, Helen J Huang, Abeena M Brewster, Kimberly H Koenig, Nuhad K Ibrahim, Funda Meric-Bernstam, Filip Janku. Everolimus, letrozole and trastuzumab in hormone receptor-positive, HER2-positive/amplified or mutant metastatic cancer: Evaluating synergy and overcoming resistance [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P1-19-18.

Circulating tumor DNA analysis in the era of precision oncology

The spatial and temporal genomic heterogeneity of various tumor types and advances in technology have stimulated the development of circulating tumor DNA (ctDNA) genotyping. ctDNA was developed as a non-invasive, cost-effective alternative to tumor biopsy when such biopsy is associated with significant risk, when tumor tissue is insufficient or inaccessible, and/or when repeated assessment of tumor molecular abnormalities is needed to optimize treatment. The role of ctDNA is now well established in the clinical decision in certain alterations and tumors, such as the epidermal growth factor receptor (EGFR) mutation in non-small cell lung cancer and the v-Ki-ras2 kirsten rat sarcoma viral oncogene homolog (KRAS) mutation in colorectal cancer. The role of ctDNA analysis in other tumor types remains to be validated. Evolving data indicate the association of ctDNA level with tumor burden, and the usefulness of ctDNA analysis in assessing minimal residual disease, in understanding mechanisms of resistance to treatment, and in dynamically guiding therapy. ctDNA analysis is increasingly used to select therapy. Carefully designed clinical trials that use ctDNA analysis will increase the rate of patients who receive targeted therapy, will elucidate our understanding of evolution of tumor biology and will accelerate drug development and implementation of precision medicine. In this article we provide a critical overview of clinical trials and evolving data of ctDNA analysis in specific tumors and across tumor types.

Pathogenic mutations and overall survival in 3,084 patients with cancer: the Hellenic Cooperative Oncology Group Precision Medicine Initiative

Background: We evaluated the association between pathogenic mutations and overall survival (OS) in patients with cancer referred to Hellenic Cooperative Oncology Group–affiliated Departments.

Patients and methods: Patients referred from 12/1980 to 1/2017 had molecular testing (for research) of archival tumor tissue collected at the time of first diagnosis (non-metastatic, 81%; metastatic, 19%). Tumor-specific gene panels (16-101 genes) were used to identify pathogenic mutations in clinically relevant genes. NGS genotyping was performed at the Laboratory of Molecular Oncology, Aristotle University of Thessaloniki. Annotation of mutations was performed at MD Anderson Cancer Center.

Results: We analyzed 3,084 patients (median age, 57 years; men, 22%) with sequencing data. Overall, 1,775 (58% of 3,084) patients had pathogenic mutations. The median follow-up was 7.52 years (95% CI, 7.39-7.61). In patients with non-metastatic tumors, after stratification by tumor type, increasing age, higher grade, and histology other than adenocarcinoma were associated with shorter OS. OS was also shorter in patients with pathogenic TP53 (HR=1.36; p<0.001), MLL3 (HR=1.64; p=0.005), and BRCA1 (HR=1.46; p=0.047) mutations compared to wild-type genes. In multivariate analyses, independent prognostic factors predicting shorter OS were pathogenic mutations in TP53 (HR=1.37, p=0.002) and MLL3 (HR=1.50, p=0.027); increasing age (HR=1.02, p<0.001); and increasing grade (HR=1.46, p<0.001). In patients with metastatic cancer, older age and higher grade were associated with shorter OS and maintained their independent prognostic significance (increasing age, HR=1.03, p<0.001 and higher grade, HR=1.73, p<0.001).

Conclusions: Analysis of molecular data reveals prognostic biomarkers, regardless of tissue or organ of origin to improve patient management.

Targeting ERBB2 (HER2) Amplification Identified by Next-Generation Sequencing in Patients With Advanced or Metastatic Solid Tumors Beyond Conventional Indications

PURPOSE

Human epidermal growth factor receptor 2 (HER2) is an effective therapeutic target in breast and gastric and gastroesophageal junction cancers. However, less is known about the prevalence of ERBB2 (HER2) amplification and the efficacy of HER2-targeted treatment in other tumors.

PATIENTS AND METHODS

We assessed HER2 amplification status among 5,002 patients with advanced disease (excluding breast cancer) who underwent next-generation sequencing. We evaluated the clinical benefit of HER2-targeted therapy by measuring the time-dependent overall survival (OS) from the genomic testing results, progression-free survival (PFS), and PFS during HER2-targeted therapy (PFS2) compared with PFS during prior therapy (PFS1).

RESULTS

Overall, 122 patients (2.4%) had HER2 amplification, including patients with endometrial (5.3%), bladder (5.2%), biliary or gallbladder (4.9%), salivary (4.7%), and colorectal cancer (3.6%). Forty patients (38%) with nongastric, nongastroesophageal junction, or nonesophageal cancers received at least one line of HER2-targeted therapy. Patients receiving HER2-targeted therapy had a median OS of 18.6 months, compared with 10.9 months for patients who did not receive HER2-targeted therapy (P = .070). On multivariable analysis, HER2-targeted therapy was significantly associated with increased OS (hazard ratio, 0.5; 95% CI, 0.27 to 0.93; P = .029), regardless of sex, age, or number of prior lines of treatment. The PFS2-to-PFS1 ratio was 1.3 or greater in 21 (57%) of 37 patients who received HER2-targeted therapy not in the first line of systemic treatment, and the median PFS2 and PFS1 times were 24 and 13 weeks, respectively (P < .001).

CONCLUSION

HER2 amplifications using next-generation sequencing can be identified in a variety of tumor types. HER2-targeted therapy may confer clinical benefit in tumor types other than those for which HER2 inhibitors are approved.

Phase 1 study of the combination of vemurafenib, carboplatin, and paclitaxel in patients with BRAF-mutated melanoma and other advanced malignancies

BACKGROUND

BRAF inhibitors are effective against selected BRAFV600 -mutated tumors. Preclinical data suggest that BRAF inhibition in conjunction with chemotherapy has increased therapeutic activity.

METHODS

Patients with advanced cancers and BRAF mutations were enrolled into a dose-escalation study (3+3 design) to determine the maximum tolerated dose (MTD) and dose-limiting toxicities (DLTs).

RESULTS

Nineteen patients with advanced cancers and BRAF mutations were enrolled and received vemurafenib (480-720 mg orally twice a day), carboplatin (area under the curve [AUC] 5-6 intravenously every 3 weeks), and paclitaxel (100-135 mg/m2 intravenously every 3 weeks). The MTD was not reached, and vemurafenib at 720 mg twice a day, carboplatin at AUC 5, and paclitaxel at 135 mg/m2 were the last safe dose levels. DLTs included a persistent grade 2 creatinine elevation (n = 1), grade 3 transaminitis (n = 1), and grade 4 thrombocytopenia (n = 1). Non-dose-limiting toxicities that were grade 3 or higher and occurred in more than 2 patients included grade 3/4 neutropenia (n = 5), grade 3/4 thrombocytopenia (n = 5), grade 3 fatigue (n = 4), and grade 3 anemia (n = 3). Of the 19 patients, 5 (26%; all with melanoma) had a partial response (PR; n = 4) or complete response (CR; n = 1); these responses were mostly durable and lasted 3.1 to 54.1 months. Of the 13 patients previously treated with BRAF and/or mitogen-activated protein kinase kinase (MEK) inhibitors, 4 (31%) had a CR (n = 1) or PR (n = 3). Patients not treated with prior platinum therapy had a higher response rate than those who did (45% vs 0%; P = .045).

CONCLUSIONS

The combination of vemurafenib, carboplatin, and paclitaxel is well tolerated and demonstrates encouraging activity, predominantly in patients with advanced melanoma and BRAFV600 mutations, regardless of prior treatment with BRAF and/or MEK inhibitors.

Physiologically-based pharmacokinetic modelling to predict oprozomib CYP3A drug-drug interaction potential in patients with advanced malignancies

AIMS

Oprozomib is an oral, second-generation, irreversible proteasome inhibitor currently in clinical development for haematologic malignancies, including multiple myeloma and other malignancies. Oprozomib is a rare example of a small molecule drug that demonstrates cytochrome P450 (CYP) mRNA suppression. This unusual property elicits uncertainty regarding the optimal approach for predicting its drug-drug interaction (DDI) risk. The current study aims to understand DDI potential during early clinical development of oprozomib.

METHODS

To support early development of oprozomib (e.g. inclusion/exclusion criteria, combination study design), we used human hepatocyte data and physiologically-based pharmacokinetic (PBPK) modelling to predict its CYP3A4-mediated DDI potential. Subsequently, a clinical DDI study using midazolam as the substrate was conducted in patients with advanced malignancies.

RESULTS

The clinical DDI study enrolled a total of 21 patients, 18 with advanced solid tumours. No patient discontinued oprozomib due to a treatment-related adverse event. The PBPK model prospectively predicted oprozomib 300 mg would not cause a clinically relevant change in exposure to CYP3A4 substrates (≤30%), which was confirmed by the results of this clinical DDI study.

CONCLUSIONS

These results indicate oprozomib has a low potential to inhibit the metabolism of CYP3A4 substrates in humans. The study shows that cultured human hepatocytes are a more reliable system for DDI prediction than human liver microsomes for studying this class of compounds. Developing a PBPK model prior to a clinical DDI study has been valuable in supporting clinical development of oprozomib.

Trial Reporting in Immuno-Oncology (TRIO): An American Society of Clinical Oncology-Society for Immunotherapy of Cancer Statement

PURPOSE

To develop recommendations for clinical trial reporting that address the unique efficacy, toxicity, and combination and sequencing aspects of immuno-oncology (IO) treatments.

METHODS

ASCO and the Society for Immunotherapy of Cancer (SITC) convened a working group that consisted of practicing medical oncologists, immunologists, clinical researchers, biostatisticians, and representatives from industry and government to develop Trial Reporting in Immuno-Oncology (TRIO) recommendations. These recommendations are based on expert consensus, given that existing data to support evidence-based recommendations are limited.

CONCLUSION

The TRIO recommendations are intended to improve the reporting of IO clinical trials and thus provide more complete evidence on the relative benefits and risks of an IO therapeutic approach. Given the rapid expansion of the number of IO clinical trials and ongoing improvements to the evidence base supporting the use of IO treatments in clinical care, these recommendations will likely need regular revision as the IO field develops.