Homologous recombination deficiency (HRD): A biomarker for first-line (1L) platinum in advanced pancreatic ductal adenocarcinoma (PDAC)

4132

Background: HRD is an emerging biomarker for platinum therapy in PDAC. The clinical implications regarding differences in outcome between germline and somatic HRD in advanced PDAC treated with 1L platinum is unexplored. Methods: We evaluated overall survival (OS) for advanced PDAC (stage III/IV) based on their pathogenic germline (gHRD) and somatic HRD (sHRD) using integrated genomic profiling from MSK-IMPACT and 1L platinum use. HRD defined by pathogenic alterations from the following genes: BRCA1/2, PALB2, ARID1A/B/2, ATR, ATRX, ATM, BAP1, RAD50/51C/D, BRIP1, NBN, CHECK1/2, FANCA/C, CDK12, and MRE11. Results: Advanced PDAC patients (n=461) treated at MSK enrolled in a prospective database, were evaluated. Median follow-up was 27.6 months (95% CI, 24.6-30.6). Both germline and somatic profilings were available for n=350 (76%) but only somatic profiling was available for n=111 (24%). We identified n=52 patients with gHRD (11.3%), n=42 patients with sHRD (9.1%), and 48 patients with somatic VUS for HRD genes. From all 461 patients, the OS was not different between 1L non-platinum vs. 1L platinum groups (19 M vs. 19.3 M), regardleess of their HRD status. (Table) The OS was superior for gHRD vs. non-gHRD (28.7 M vs. 18.2 M), regardless of 1L treatment choice. However, similar significant OS superiority was neither observed in sHRD vs. non-sHRD, nor in VUS sHRD vs. non-VUS sHRD. In a subgroup analysis of 1L platinum treated patients, the OS was superior in gHRD vs. non-gHRD (NR vs. 17.9 M); however, there was no OS difference between sHRD and non-sHRD. Conclusions: In advanced PDAC patients, only gHRD predicted better overall survival for first-line platinum chemotherapy. These findings emphasize the importance of germline mutation testing of HRD in PDAC. Biomarker validation and functional definition of HRD such as loss of heterozygosity analysis is underway. [Table: see text]

Genomic profiling in pancreatic ductal adenocarcinoma and a pathway towards therapy individualization: A scoping review

CONTEXT

Pancreatic cancer (PDAC) is one of the most challenging cancers to treat with modest recent improvements in survival from new systemic therapies. There is growing interest in individualized therapy underpinned by somatic and germline genomic alterations.

OBJECTIVE

A systematic review of data on therapies targeting somatic and germline alterations, and their downstream pathways in PDAC.

METHOD

A systematic literature search was conducted using PRISMA guidelines to include relevant results published after January 1, 2008.

RESULTS

A total of 71 relevant studies were included. We identified 36 studies targeting the KRAS-pathway, the most common being with MEK-inhibitor therapy. Twenty-two studies were identified that evaluated platinum-based chemotherapy and PARP inhibitors in patients with deleterious mutations in DNA damage repair genes and have shown encouraging results. Immunotherapy has demonstrated activity in patients with mismatch repair deficiency/microsatellite instability.

CONCLUSION

Evidence from translational and clinical research presents an exciting platform for genomic targeted therapy in PDAC. Validity for targeting BRCA with platinum and PARP inhibitors and microsatellite instability with immune therapy has been established, nonetheless, evidence for targeting the common driver oncogenes is lacking and much work is needed. Of importance is identifying the subgroup of KRAS -wild type PDAC (approximately 5%) where there is enrichment for targetable opportunities.

Pilot study of plasma KRAS as a prognostic biomarker in localized pancreas ductal adenocarcinoma (PDAC)

294

Background: Validated predictive and prognostic biomarkers are needed in PDAC. Such biomarkers could predict response and resistance early in treatment. As 95% of PDAC harbor KRAS mutations (mKRAS), plasma mKRAS has utility as a biomarker. We explored the prognostic value of mKRAS in a PDAC cohort at Memorial Sloan Kettering. Methods: 10 mL of whole blood was collected at diagnosis of localized PDAC and early interval CT scan (approx. 8 weeks). DNA was extracted with QIAamp DNA kits (Qiagen, Valencia, CA). Single locus, if tissue KRAS known, or multiplex (G12A, G12C, G12D, G12R, G12S, G12V, G13D) digital droplet PCR (ddPCR) was performed with QX200 (BioRad, Hercules, CA) ddPCR system. Disease status was determined by radiographic, CA19-9 and clinical evaluation. Results: N = 18 enrolled (median age: 65 [range 34-85]). Median time between baseline (B) and interval (I) blood was 2.53 months (range 0.9-6). One had locally recurrent disease, 2 AJCC stage IIa, 1 IIb and 14 III. Three had tissue KRAS G12D mutation, 6 G12V and 9 unknown. Eight had gemcitabine-based treatment, 10 5-FU-based and 5 radiation. See table. mKRAS and CA19-9 at B were not associated with progression free survival (PFS) or overall survival (OS). mKRAS detection at I was associated with shorter PFS/OS (P < 0.01), but CA19-9 was not. mKRAS change from B to I was also associated with PFS/OS. For every 1 copy/mL increase in the change of mKRAS from B to I, the risk of death or progression/death increased by nearly 2 fold after controlling for baseline value (p = 0.01 for OS, p = 0.03 for PFS). Four patients, all undetectable mKRAS at I, went to surgery; 2/4 resected. Conclusions: In this pilot, 59% of localized PDAC patients had detectable mKRAS at B. mKRAS detection at I and change from B to I were associated with PFS/OS supporting that mKRAS early in treatment may be a useful prognostic and predictive marker in localized PDAC. We have initiated a large prospective trial to evaluate the predictive and prognostic potential of plasma mKRAS in advanced PDAC. [Table: see text]

A randomized phase II study of cabiralizumab (cabira) + nivolumab (nivo) ± chemotherapy (chemo) in advanced pancreatic ductal adenocarcinoma (PDAC)

TPS465

Background: Treatment options for PDAC are limited; thus, new therapies that can improve outcomes and extend survival are needed. PDAC is associated with high infiltration by tumor-associated macrophages (TAMs) that inhibit antitumor T-cell activity. Blocking colony-stimulating factor 1 receptor (CSF-1R) signaling—which supports the recruitment, differentiation, and maintenance of immunosupressive macrophages in tumors—may lead to depletion of TAMs and upregulation of T-cell checkpoints. Cabira, a humanized IgG4 monoclonal antibody, binds to CSF-1R and blocks its signaling, a key determinant of TAM activation and survival. By reducing TAMs and promoting a proinflammatory microenvironment, cabira may stimulate T-cell responses, thereby sensitizing PDAC to therapy with nivo (anti‒PD-1). In a phase 1a/b study cabira + nivo was tolerable and showed evidence of on-target tumor immune modulation and durable clinical benefit in heavily pretreated patients (pts) with advanced PDAC (Wainberg et al. J Immunother Cancer. 2017 [abst O42]; Carleton et al. J Clin Oncol. 2018 [abst 3020]). Here we describe a randomized, open-label, phase 2 study evaluating the safety and efficacy of cabira + nivo ± chemo in advanced PDAC. Methods: Pts aged ≥18 y with locally advanced/metastatic PDAC that progressed on/after first-line chemo (gemcitabine [gem] or 5-fluorouracil [5-FU] based) will be enrolled. Pts with active/suspected autoimmune disease, uncontrolled/significant cardiovascular disease, or prior exposure to select immune cell–modulating antibodies are not eligible. Depending on prior chemo received, pts will be randomized to 1 of 4 arms (n≈40 each): cabira + nivo; cabira + nivo + gem/nab-paclitaxel; cabira + nivo + oxaliplatin/5-FU/leucovorin; or investigator’s choice of standard-of-care chemo. Endpoints include median progression-free survival (primary), overall survival rate, objective response rate, median duration of response, pharmacokinetics, and safety. In a completed preliminary safety cohort, 12 pts were treated with cabira + nivo + chemo and monitored for 4 wk; competitive enrollment is open, with 32 pts enrolled. (NCT03336216, NCT02526017) Clinical trial information: NCT03336216.

Ampullary cancer: Evaluation of somatic and germline genetic alterations and association with clinical outcomes

BACKGROUND

Ampullary carcinoma (AC) is a rare gastrointestinal cancer. Pathogenic germline alterations (PGAs) in BRCA2 and potentially targetable somatic alterations (SAs) in ERBB2 and ELF3 have been previously described in AC. Memorial Sloan Kettering Cancer Center has implemented an opt-in strategy for germline testing (GT) and somatic testing (ST) for patients with AC to further evaluate the spectrum of PGAs and SAs.

METHODS

Forty-five patients with pathologically confirmed AC prospectively consented with the Memorial Sloan Kettering Integrated Mutation Profiling of Actionable Cancer Targets (MSK-IMPACT) test (410-468 genes). A subset of the cohort (23 of the 45 patients) also consented to GT with MSK-IMPACT (76-88 genes). Germline data for 21 of the remaining 22 patients who had not consented to GT were obtained in a de-identified fashion without clinical correlation. Clinicopathologic features, treatment histories, and survival data for consenting patients were collected and analyzed.

RESULTS

Pancreaticobiliary, intestinal, and mixed features of the 2 types were the primary pathologic subtypes of AC identified in this cohort. No difference in median overall survival was found between pathologic subtypes. Eight of 44 patients (18%) were identified as harboring pathogenic mutations in BRCA2, ATM, RAD50, and MUTYH. In addition, this study found a wide spectrum of SAs in genes such as KRAS, MDM2, ERBB2, ELF3, and PIK3CA. Two patients in the cohort underwent SA-targeted therapy, and 1 had a partial radiographic response.

CONCLUSIONS

Mutations in multiple somatic and germline genes were identified in this cohort. Significantly, actionable targets were identified in the tumors, and broader testing for PGAs and SAs should be considered for all patients with AC.

Genomic Landscape of Pancreatic Adenocarcinoma in Younger versus Older Patients: Does Age Matter?

PURPOSE

State-of-the-art genomic analyses of pancreatic adenocarcinoma (PDAC) have yielded insight into signaling pathways underlying carcinogenesis. PDAC is characterized by substantial genomic heterogeneity. We aimed to determine whether early-onset PDAC (EOPC; ≤55 years) displays a distinctive molecular landscape from average-age onset PDAC (AOPC; ≥70 years).

EXPERIMENTAL DESIGN

Three distinct datasets for PDAC were analyzed. In the first, patients undergoing treatment at Memorial Sloan Kettering (MSK) were consented for MSK-IMPACT next-generation sequencing. The second cohort analyzed was The Cancer Genome Atlas (TCGA) dataset for differences in somatic mutations, gene expression, and protein expression. The third dataset was an Australian cohort of PDAC. Clinical data were correlated with genomic analyses.

RESULTS

A total of 293 samples were analyzed, yielding 90 patients aged ≤55 years and 203 patients aged ≥70 years. Among the genes known to be associated with carcinogenesis, SMAD4 displayed higher mutation rates in younger patients. Comprehensive transcriptomic analysis of cellular pathways indicated that the TGFβ pathway has increased activation, and the expression levels of phospho-GSK3 were higher in EOPC. Survival outcomes revealed no differences between age groups.

CONCLUSIONS

These exploratory analyses suggest that there may be somatic gene alterations within the population of patients with early-onset PDAC that involve unique cellular pathways compared with average-onset PDAC. Former studies imply these cellular pathways may play a role in smoking-related PDAC carcinogenesis. Larger genomic datasets are warranted for future evaluation to extend these observations.

Binimetinib plus Gemcitabine and Cisplatin Phase I/II Trial in Patients with Advanced Biliary Cancers

PURPOSE

Mutations in the RAS/RAF/MEK/ERK signaling pathway are commonly found in biliary tract cancer (BTC). Binimetinib, a selective inhibitor of MEK1/2, has single-agent activity. Preclinical data support binimetinib combination with chemotherapy, when given in an interrupted dosing schedule.Patients and Methods: A phase I/II trial evaluated binimetinib in combination with gemcitabine and cisplatin in patients with untreated advanced BTC. The primary endpoints were to determine the MTD (phase I), and PFS 6 and RR (phase II). Tumor tissue for targeted gene sequencing and blood samples for peripheral blood pERK expression were evaluated. Patients received oral binimetinib twice daily with gemcitabine and cisplatin on day 8 and 15 of a 21-day cycle. Binimetinib was held for 2 days prior to and on day of each chemotherapy treatment.

RESULTS

Twelve patients enrolled in the phase I showed the MTD of binimetinib at 45 mg orally twice daily with gemcitabine 800 and cisplatin 20 mg/m². Twenty-nine patients were treated in the phase II. Six patients treated at MTD in phase I were evaluable as part of phase II. PFS 6 months was 54% and RR was 36%. Median overall survival was 13.3 months (95% CI, 9.8-16.5). MSK-IMPACT 410-gene panel showed aberrations in the RAS-RAF-MEK-ERK pathway and mutations in PIK3CA, AKT2, PIK3CG, BRAF, and MAP3K1 in responding patients.

CONCLUSIONS

Binimetinib with gemcitabine and cisplatin did not show an improvement in PFS 6 and RR. Molecular profiling may help select patients who may benefit from this triplet therapy, which is not planned at this time.

Circulating Tumor and Invasive Cell Gene Expression Profile Predicts Treatment Response and Survival in Pancreatic Adenocarcinoma

Previous studies have shown that pharmacogenomic modeling of circulating tumor and invasive cells (CTICs) can predict response of pancreatic ductal adenocarcinoma (PDAC) to combination chemotherapy, predominantly 5-fluorouracil-based. We hypothesized that a similar approach could be developed to predict treatment response to standard frontline gemcitabine with nab-paclitaxel (G/nab-P) chemotherapy. Gene expression profiles for responsiveness to G/nab-P were determined in cell lines and a test set of patient samples. A prospective clinical trial was conducted, enrolling 37 patients with advanced PDAC who received G/nab-P. Peripheral blood was collected prior to treatment, after two months of treatment, and at progression. The CTICs were isolated based on a phenotype of collagen invasion. The RNA was isolated, cDNA synthesized, and qPCR gene expression analyzed. Patients were most closely matched to one of three chemotherapy response templates. Circulating tumor and invasive cells' SMAD4 expression was measured serially. The CTICs were reliably isolated and profiled from peripheral blood prior to and during chemotherapy treatment. Individual patients could be matched to distinct response templates predicting differential responses to G/nab-P treatment. Progression free survival was significantly correlated to response prediction and ΔSMAD4 was significantly associated with disease progression. These findings support phenotypic profiling and ΔSMAD4 of CTICs as promising clinical tools for choosing effective therapy in advanced PDAC, and for anticipating disease progression.

Prospective Evaluation of Germline Alterations in Patients With Exocrine Pancreatic Neoplasms

Background

Identification of pathogenic germline alterations (PGAs) has important clinical and therapeutic implications in pancreas cancer. We performed comprehensive germline testing (GT) in an unselected prospective cohort of patients with exocrine pancreatic neoplasms with genotype and phenotype association to facilitate identification of prognostic and/or predictive biomarkers and examine potential therapeutic implications.

Methods

Six hundred fifteen unselected patients with exocrine pancreatic neoplasms were prospectively consented for somatic tumor and matched sample profiling for 410-468 genes. GT for PGAs in 76 genes associated with cancer susceptibility was performed in an "identified" manner in 356 (57.9%) patients and in an "anonymized" manner in 259 (42.1%) patients, using an institutional review board-approved protocol. Detailed clinical and pathological features, response to platinum, and overall survival (OS) were collected for the identified cohort. OS was analyzed with Kaplan-Meier curves.

Results

PGAs were present in 122 (19.8%) of 615 patients involving 24 different genes, including BRCA1/2, ATM, PALB2, and multiple additional genes associated with the DNA damage response pathway. Of 122 patients with germline alterations, 41.8% did not meet current guidelines for GT. The difference in median OS was not statistically significant between patients with and without PGA (50.8 months, 95% confidence interval = 34.5 to not reached, two-sided P = .94). Loss of heterozygosity was found in 60.0% of BRCA1/2.

Conclusions

PGAs frequently occur in pancreas exocrine neoplasms and involve multiple genes beyond those previously associated with hereditary pancreatic cancer. These PGAs are therapeutically actionable in about 5% to 10% of patients. These data support routinely offering GT in all pancreatic ductal adenocarcimona patients with a broad panel of known hereditary cancer predisposition genes.

Nanoliposomal irinotecan with fluorouracil for the treatment of advanced pancreatic cancer, a single institution experience

Background

Effective treatment options for advanced pancreatic cancer are finite. NAPOLI-1, a phase III randomized trial, demonstrated the efficacy of nanoliposomal irinotecan with fluorouracil/leucovorin (nal-IRI + 5-FU/LV) for the treatment of advanced pancreatic cancer following progression on gemcitabine-based chemotherapy. There are limited additional data on the safety and efficacy of nal-IRI + 5-FU/LV following FDA approval in October 2015. We examined the post-approval safety and effectiveness of nal-IRI + 5-FU/LV in advanced pancreatic cancer patients receiving treatment at Memorial Sloan Kettering Cancer Center.

Methods

A retrospective chart review was conducted of all patients beginning treatment with nal-IRI + 5-FU/LV from October 2015 through June 2017. Using the electronic medical record and institutional database, information was extracted pertaining to demographics, performance status (ECOG), prior therapies, dose, duration of treatment, adverse events, progression free survival (PFS), overall survival (OS) and treatment response.

Results

Fifty six patients were identified. Median progression free survival (PFS) was 2.9 months and median overall survival (OS) was 5.3 months. Patients with prior disease progression on irinotecan experienced PFS and OS of 2.2 and 3.9 mo, respectively. Patients without prior irinotecan exposure experienced significantly longer PFS (4.8 mo, p = 0.02) and OS (7.7 mo, p = 0.002), as did patients who received prior irinotecan without disease progression (PFS, 5.7 mo, p = 0.04; OS, 9.0 mo, p = .04). Progression on prior irinotecan was associated with greater lines of prior advanced disease chemotherapy (2 vs 1). Dose reductions (DR) were most frequently due to fatigue (42%) and diarrhea (37%), but were not associated with worse outcomes. In fact, patients with ≥1 DR experienced longer PFS (5.4 v 2.6 mo, p = 0.035). Sequential therapy with nab-paclitaxel + gemcitabine (nab-P + Gem) followed by nal-IRI + 5-FU/LV (n = 25) resulted in OS of 23.0 mo. Mutations in TP53 were associated with shorter PFS.

Conclusions

These data support the safety and efficacy of nal-IRI + 5-FU/LV, reinforcing results of NAPOLI-1. Patients without disease progression on prior irinotecan fared significantly better than patients with progression, when treated with nal-IRI + 5-FU/LV. Sequential therapy with nab-P + Gem followed by nal-IRI + 5-FU/LV demonstrates encouraging median OS. These findings provide guidance for patients most likely to benefit from nal-IRI + 5-FU/LV.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4605-1) contains supplementary material, which is available to authorized users.

Brain Metastases in Pancreatic Ductal Adenocarcinoma: Assessment of Molecular Genotype-Phenotype Features-An Entity With an Increasing Incidence?

PURPOSE

To assess clinical characteristics of patients with metastatic pancreas ductal adenocarcinoma (PDAC) and brain metastases (BM), and to assess somatic and germ-line molecular profiles where performed.

PATIENTS AND METHODS

Patients with PDAC and BM between January 1990 and January 2016 were identified. Molecular characteristics of somatic and germ-line testing where performed in the subset of patients who had provided informed consent. Somatic alterations were assessed by either MSK-IMPACT testing (>340 key cancer genes) or Sequenom testing (8-gene panel). Overall survival was calculated from date of diagnosis to either date of last follow-up or death. Survival after BM was calculated from date of diagnosis of BM by radiology or pathology to either date of last follow-up or death.

RESULTS

From a total of 5824 patients with PDAC identified from January 2000 to January 2016, twenty-five patients (0.4%) had BM. Median age at PDAC diagnosis was 58 years. Median time to the development of BM from initial PDAC diagnosis was 17 months (range, 0-79 months). Median overall survival after BM diagnosis was 1.5 months (range, 1-31 months). Overall survival for patients who had craniotomy (n = 4) was 11 months (range, 1-31 months), with 2 long-term survivors at 21 and 31 months, respectively. Four patients had leptomeningeal disease. Six of 25 patients had germ-line testing, and 3 had BRCA mutations (2 BRCA1 and 1 BRCA2). Somatic profiling identified KRAS mutations in 100% (4 G12D, 2 G12V, and 1 Q61K).

CONCLUSION

BM from PDAC is a rare event. We identified a speculative association of germ-line BRCA1/2 alterations with BM in PDAC, which requires corroboration. Survival after BM development is poor; prolonged survival occurred in selected patients via a multidisciplinary approach.

Incidence, Management, and Implications of Visceral Thrombosis in Pancreatic Ductal Adenocarcinoma

BACKGROUND

Visceral or splanchnic thrombosis is defined as thrombi within the hepatoportal venous system, including portal (PV), mesenteric (MV), and splenic vein (SV), as well as thrombi in renal or gonadal veins. There are limited data to evaluate the prognostic significance, incidence, and clinical management of visceral thromboses in patients with pancreatic ductal adenocarcinoma (PDAC).

PATIENTS AND METHODS

We conducted an analysis of 95 patients treated at Memorial Sloan Kettering Cancer Center with PDAC who had a visceral thrombosis.

RESULTS

A total of 153 visceral thromboses (VsT) were identified in 95 patients (n = 51, 54% woman). A total of 36 patients (37%) had locally advanced disease, and n = 59 (62%) had metastatic disease. Systemic therapies received included FOLFIRINOX (n = 57, 60%) and GC/PTX (n = 27, 28%). All VsT events were incidentally detected. Overall survival of cohort was 12.3 months (range, 10.2-14.4 months). Visceral thrombosis incidence in the cohort was as follows: portal vein (PV) (45%), MV (26%), SV (17%), and gonadal veins (8%). Time to develop first VsT was 4.3 months (range, 3-5.6 months), and time to death from VsT development was 1.87 months (range, 0.8-2.8 months). Forty-five patients (47%) developed a second VsT. Sixty percent had a Khorana risk score of > 3. Thirty-nine patients (41%) were treated with short-term anticoagulation (AC) (< 1 month) (low-molecular-weight heparin, n = 34). Forty-five patients (47%) were treated with long-term AC (> 1 month) (low-molecular-weight heparin, n = 32; 23 were transitioned to an oral anticoagulant). Twenty-two patients (23%) were not treated with AC. Eight patients (8%) had a bleeding complication from AC. Portal vein thrombosis had the shortest overall survival at 3.6 months (range, 2.3-4.8 months).

CONCLUSION

In PDAC, VsT can frequently present as an incidental finding on routine abdominal imaging. The most common location is PV, followed by MV and SV. We observed that AC is underutilized in this setting despite a low bleeding complication rate. PV was associated with the least overall survival of the VsT. Future large prospective studies should explore the role of AC and value in this setting.

Visceral Thromboses in Pancreas Adenocarcinoma: Systematic Review

Within gastrointestinal malignancies, primary hepatocellular carcinoma and pancreatic ductal adenocarcinoma (PDAC) are frequently associated with visceral thromboses (VT). Thrombus formation in the portal (PVT), mesenteric (MVT), or splenic vein (SVT) system leads to portal hypertension and intestinal ischemia. VT in PDAC may convey a risk of increased distal thrombosis and poses therapeutic uncertainty regarding the role of anticoagulation. An increasing number of reports describe VT associated with PDAC. It is possible that early diagnosis of these events may help reduce morbidity and speculatively improve oncologic outcomes. To perform a systematic review to study PVT, MVT, and SVT associated with PDAC, and to provide a comprehensive review. Medline/PubMed, Embase, Web of Science, Scopus, and the Cochrane Library. Data Extraction and Assessment: Two blinded independent observers extracted and assessed the studies for diagnosis of PVT, MVT, and SVT in PDAC. Studies were restricted to English-language literature published between 2007 and 2016. Eleven articles were identified. Five case reports and 7 retrospective studies were found, with a total of 127 patients meeting the inclusion criteria. The mean age at diagnosis was 64 years. PVT was found in 35% (n = 46), SVT in 52% (n = 65), and MVT in 13% (n = 15). Mean follow-up time was 26 months. Only 3 of the selected articles studied the impact of anticoagulation in VT. All patients with nonvisceral thrombosis (eg, deep-vein thrombosis, pulmonary emboli) were therapeutically treated; in contrast, patients with VT only rarely received treatment. VT in PDAC is a frequent finding at diagnosis or during disease progression. Evidence to guide treatment choices is limited, and current management is based on inferred experience from nononcologic settings. Anticoagulation appears to be safe in VT, with most of the large studies recommending a careful assessment for patients at a high risk of bleeding.

Organoid Profiling Identifies Common Responders to Chemotherapy in Pancreatic Cancer

Pancreatic cancer is the most lethal common solid malignancy. Systemic therapies are often ineffective, and predictive biomarkers to guide treatment are urgently needed. We generated a pancreatic cancer patient-derived organoid (PDO) library that recapitulates the mutational spectrum and transcriptional subtypes of primary pancreatic cancer. New driver oncogenes were nominated and transcriptomic analyses revealed unique clusters. PDOs exhibited heterogeneous responses to standard-of-care chemotherapeutics and investigational agents. In a case study manner, we found that PDO therapeutic profiles paralleled patient outcomes and that PDOs enabled longitudinal assessment of chemosensitivity and evaluation of synchronous metastases. We derived organoid-based gene expression signatures of chemosensitivity that predicted improved responses for many patients to chemotherapy in both the adjuvant and advanced disease settings. Finally, we nominated alternative treatment strategies for chemorefractory PDOs using targeted agent therapeutic profiling. We propose that combined molecular and therapeutic profiling of PDOs may predict clinical response and enable prospective therapeutic selection.Significance: New approaches to prioritize treatment strategies are urgently needed to improve survival and quality of life for patients with pancreatic cancer. Combined genomic, transcriptomic, and therapeutic profiling of PDOs can identify molecular and functional subtypes of pancreatic cancer, predict therapeutic responses, and facilitate precision medicine for patients with pancreatic cancer. Cancer Discov; 8(9); 1112-29. ©2018 AACR.See related commentary by Collisson, p. 1062This article is highlighted in the In This Issue feature, p. 1047.

Pancreas adenocarcinoma: novel therapeutics

Pancreatic ductal adenocarcinoma (PDAC) is the third highest cause of cancer-related deaths in the US, and is projected to be second only to non-small cell lung cancer (NSCLC) by the 2020s. Current therapies have a modest impact on survival and median overall survival (mOS) across all stages of disease remains under a year. Over the last decade, however, great strides have been made in the understanding of PDAC pathobiology including the role of the tumor microenvironment (TME), DNA damage repair and mechanism of immunosuppression. Exciting novel therapeutics are in clinical development targeting the TME to increase cytotoxic drug delivery, decrease immunosuppressive cell presence and attack cancer stem cells (CSCs). Immune checkpoint inhibitors, cancer vaccines and other immunotherapies are actively being studied and novel combinations of targeted agents are being pursued. There is a sense of optimism in the oncology community that these scientific advances will translate into improved outcomes for patients with PDAC in the proximate future. In this review, we examine various novel therapeutics under clinical development with a focus on stromal disrupting agents, immunotherapeutics and DNA damage repair strategies.

Preclinical models of pancreatic ductal adenocarcinoma

Unlike many other cancers, pancreatic ductal adenocarcinoma (PDAC) has seen only incremental improvement in mortality despite significant advances in our understanding of the underlying biology. A primary obstacle to progress has been our inability to properly model PDAC in a preclinical setting. PDAC is difficult to study because of its genetic heterogeneity, intricate stromal microenvironment, and complex interplay with our immune system. Finding a model that properly accounts for all these criteria remains difficult. This review summarizes the five primary models currently in use: human PDAC cell line, cell line xenograft, patient derived xenograft, genetically engineered mouse model (GEMM), and organoids. We delve into the advantages of disadvantages of each model, while discussing how each model has been or could be used in the preclinical setting.

Phase 1 trial evaluating cisplatin, gemcitabine, and veliparib in 2 patient cohorts: Germline BRCA mutation carriers and wild-type BRCA pancreatic ductal adenocarcinoma

BACKGROUND

A phase 1 trial was used to evaluate a combination of cisplatin, gemcitabine, and escalating doses of veliparib in patients with untreated advanced pancreatic ductal adenocarcinoma (PDAC) in 2 cohorts: a germline BRCA1/2-mutated (BRCA+) cohort and a wild-type BRCA (BRCA-) cohort. The aims were to determine the safety, dose-limiting toxicities (DLTs), maximum tolerated dose, and recommended phase 2 dose (RP2D) of veliparib combined with cisplatin and gemcitabine and to assess the antitumor efficacy (Response Evaluation Criteria in Solid Tumors, version 1.1) and overall survival.

METHODS

Gemcitabine and cisplatin were dosed at 600 and 25 mg/m2 , respectively, over 30 minutes on days 3 and 10 of a 21-day cycle. Four dose levels of veliparib were evaluated: 20 (dose level 0), 40 (dose level 1), and 80 mg (dose level 2) given orally twice daily on days 1 to 12 and 80 mg given twice daily on days 1 to 21 (dose level 2A [DL2A]).

RESULTS

Seventeen patients were enrolled: 9 BRCA+ patients, 7 BRCA- patients, and 1 patient with an unknown status. DLTs were reached at DL2A (80 mg twice daily on days 1 to 21). Two of the 5 patients in this cohort (40%) experienced grade 4 neutropenia and thrombocytopenia. Two grade 5 events occurred on protocol. The objective response rate in the BRCA+ cohort was 7 of 9 (77.8%). The median overall survival for BRCA+ patients was 23.3 months (95% confidence interval [CI], 3.8-30.2 months). The median overall survival for BRCA- patients was 11 months (95% CI, 1.5-12.1 months).

CONCLUSIONS

The RP2D of veliparib was 80 mg by mouth twice daily on days 1 to 12 in combination with cisplatin and gemcitabine; the DLT was myelosuppression. Substantial antitumor activity was seen in BRCA+ PDAC. A randomized phase 2 trial is currently evaluating cisplatin and gemcitabine with and without veliparib for BRCA+ PDAC (NCT01585805). Cancer 2018;124:1374-82. © 2018 American Cancer Society.

Evaluating Mismatch Repair Deficiency in Pancreatic Adenocarcinoma: Challenges and Recommendations

Purpose: Immune checkpoint inhibition has been shown to generate profound and durable responses in mismatch repair deficient (MMR-D) solid tumors and has elicited interest in detection tools and strategies to guide therapeutic decision-making. Herein we address questions on the appropriate screening, detection methods, patient selection, and initiation of therapy for MMR-D pancreatic ductal adenocarcinoma (PDAC) and assess the utility of next-generation sequencing (NGS) in providing additional prognostic and predictive information for MMR-D PDAC.Experimental Design: Archival and prospectively acquired samples and matched normal DNA from N = 833 PDAC cases were analyzed using a hybridization capture-based, NGS assay designed to perform targeted deep sequencing of all exons and selected introns of 341 to 468 cancer-associated genes. A computational program using NGS data derived the MSI status from the tumor-normal paired genome sequencing data. Available germline testing, IHC, and microsatellite instability (MSI) PCR results were reviewed to assess and confirm MMR-D and MSI status.Results: MMR-D in PDAC is a rare event among PDAC patients (7/833), occurring at a frequency of 0.8%. Loss of MMR protein expression by IHC, high mutational load, and elevated MSIsensor scores were correlated with MMR-D PDAC. All 7 MMR-D PDAC patients in the study were found to have Lynch syndrome. Four (57%) of the MMR-D patients treated with immune checkpoint blockade had treatment benefit (1 complete response, 2 partial responses, 1 stable disease).Conclusions: An integrated approach of germline testing and somatic analyses of tumor tissues in advanced PDAC using NGS may help guide future development of immune and molecularly directed therapies in PDAC patients. Clin Cancer Res; 24(6); 1326-36. ©2018 AACR.

Nano-liposomal irinotecan and 5-FU/LV (N+F) for the treatment of advanced PDAC: Memorial Sloan Kettering (MSK) Single Cancer Center Evaluation

471

Background: Therapy options for advanced pancreatic adenocarcinoma (PDAC) are finite. NAPOLI-1, a phase III randomized trial, demonstrated the efficacy of N+F following progression on gemcitabine (G) based therapy (mPFS 3.1 mo, mOS 6.1 mo). There are limited additional data on the safety and efficacy of N+F following FDA approval in October 2015. We examined the post approval safety, tolerability and effectiveness of N+F in advanced PDAC patients at MSK. Methods: A retrospective chart review was conducted of all patients treated with N+F from Feb 2016 and ending in Aug 2017. Using the EMR and institutional database, information was extracted pertaining to demographics, performance status (ECOG), prior therapies, dose, duration of N+F, adverse events, PFS, OS and treatment response per RECIST. Results:N = 56 identified. Demographics: M/F 29/27, age 68 (range 42-88), prior lines of palliative chemotherapy (0/1/2/3/ > 3, 4/20/21/11). Median PFS was 2.9 months and median OS was 5.3 months. There was a significant difference in PFS, OS and prior lines of therapy between patients who previously progressed on irinotecan (N = 27) versus not (N = 29); PFS = 2.4 v 4.8 mo, p = 0.0154; OS = 3.9 v 8.4 mo, p = 0.0021; 2 v 1 line. ECOG score was not predictive of PFS or OS. There were 19 dose reductions (DR), most frequent reasons: fatigue (42%) and diarrhea (37%). Regarding RECIST: PR = 2 (4%), SD = 19 (34%). 10/43 (23%) experienced > 50% CA 19-9 reduction. Dose reductions were not associated with worse outcomes, in fact, patients with 1 or more DR experienced significantly longer PFS v none (DR 2, not reached; DR 1, 5.2 mo; DR 0, 2.5 mo, p = 0.0185). For the subset who received sequential therapy with G+nab-paclitaxel (P) followed by N+F (N = 25) mOS of 25.4 mo. Conclusions: These data support the safety and efficacy of N+F, re-inforcing results of NAPOLI-1. Patients whose disease previously progressed on irinotecan fared significantly worse than patients who did not, when treated with N+F. N+F appears active even in patients requiring DR. Sequential therapy with G+P followed by N+F demonstrates encouraging mOS. Collectively these findings underscore the utility of N+F in the therapy of advanced PDAC.

Pilot study of gemcitabine, nab-paclitaxel, PEGPH20, and rivaroxaban for advanced pancreatic adenocarcinoma: An interim analysis

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Background: PEGPH20 (P) degrades hyaluronan (HA), a key component of pancreatic adenocarcinoma (PDAC) tumor microenvironment, leading to reduction of tumor interstitial pressure, decompression of tumor blood vessels and improvement in delivery of chemotherapeutics. A prior study of P with chemotherapy in PDAC (HALO-202) found an increased risk of thromboembolic (TE) events, 43%, effectively reduced with subcutaneous enoxaparin treatment. Rivaroxaban (R) is a safe and effective oral anticoagulant for treating cancer-related TE. Methods: 28 patients with advanced PDAC, KPS ≥ 70 and without prior TE were enrolled from January to June 2017. Patients received treatment with PAG (P; 3 µg/kg IV 2x/wk x 3 wks in C1, then 1x/wk x 3 wks in C2+, plus AG) every 28 days, with R (15 mg twice daily for 21 days, followed by 20 mg once daily). Primary endpoint is symptomatic TE event rate; secondary endpoints include PFS, OS, major bleeding rate and RR. Results: All 28 patients are evaluable for efficacy and safety. Key patient characteristics: age = 62 (range 45-76), M/F = 15/13, stage III/IV = 4/24, KPS 70/80/90 = 1/13/14. Median follow-up is 5.4 mo. No symptomatic and one grade 2, asymptomatic TE event (DVT) occurred (1/28 = 3.6%). Two grade 3 GI hemorrhages occurred. Best responses: partial response 11 (39%), stable disease 13 (46%), progressive disease 4 (14%), and overall disease control rate of 86%. Median PFS and OS have not been reached. Conclusions: Interim analysis shows R is safe and effectively prevents TE events in patients receiving PAG. Responses and disease control rate are encouraging in this tumor HA-level unselected patient population. Updated safety and efficacy data will be reported. Clinical trial information: NCT02921022.

Plasma KRAS as a biomarker for pancreatic ductal adenocarcinoma (PDAC)

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Background: PDAC needs validated diagnostic biomarkers for early detection and predictive markers for outcome. As 95% of PDACs harbor KRAS mutations (mKRAS), circulating tumor DNA (ctDNA) has potential utility in PDAC. We assessed the ability to detect and correlate mKRAS in a metastatic PDAC cohort from Memorial Sloan Kettering Cancer Center. Methods: 10 mL of whole blood was collected. cfDNA was extracted with QIAmp or QIAsymphony DNA extraction kits (Qiagen, Valencia, CA). Directed (KRAS G12D, G12R, G12V, Q61H) or multiplex (G12A, G12C, G12D, G12R, G12S, G12V, G13D) digital droplet PCR (ddPCR) was performed with Raindrop Plus (Raindance Technologies, Billerica, MA) or QX200 (BioRad, Hercules, CA) ddPCR systems. Number and size of liver, lung and lymph node metastases, peritoneal disease (mild, moderate, severe), ascites (trace, small, large) and bone mets (Y/N) were assessed by CT scan. Results: See table. 21 (55%) had detectable ctDNA (ctDNA(+)) with mean mutant allele fraction of 4.5% (0.015-36.8). ctDNA (+) vs (-) PFS and OS from collection were 6.9 and 8.4 months vs. 9.9 and 10.5 (p=0.89 for both). CA19-9, PFS and OS did not correlate with ctDNA tertile (p=0.15, 0.54 & 0.50). On treatment and disease activity were not associated with ctDNA status (p= 0.20 & 0.60). Number and size of liver mets were associated with ctDNA (+) (p=0.006 & 0.007). Conclusions: ctDNA KRAS detection was measurable in metastatic disease with rates consistent with other PDAC reports. Median PFS, OS were lower in ctDNA (+) group but not statistically significant in this diverse cohort. Number and size of liver metastases were significantly higher in ctDNA (+). Future study should focus on practice changing applications with standardized collection, intra-patient comparisons and role of liver disease burden. We have initiated studies to evaluate plasma KRAS prior to and during treatment to address its value as a predictive assay and explore factors affecting ctDNA detection. [Table: see text]

Prospective analysis of somatic and germline genetic alterations in patients with ampullary carcinomas

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Background: Ampullary carcinoma (AC) is a rare gastrointestinal cancer. Germline alterations (GA) in BRCA2 have been identified in patients with AC. Also, potentially targetable somatic alterations (SA) in other genes including ERBB2, and ELF3 have been identified in AC. MSKCC has implemented an opt-in strategy for germline (GT) and somatic genetic testing (ST) for patients with AC. Methods: Patients (pts) with pathologically confirmed AC were consented prospectively for ST using MSK-IMPACT (410 genes). A subset of pts was also consented for GT using MSK-IMPACT (76 genes) under an IRB approved protocol. Clinicopathologic features, treatment history and survival data were collected and analyzed. Results: N = 36 AC pts consented to ST from 9/2016 to 4/2017 of which 19/36 (52.7%) were male. Median age at diagnosis was 63 years, range 35-81. Pathology: 6/36 (16.7%) intestinal subtype, 19/36 (52.7%) pancreaticobiliary subtype, 4/36 (11.1%) mixed type, and 7/36 (19.4%) undifferentiated/other subtypes.29/36 (80.5%) pts had a family history of cancer. SA in KRAS 11/36 (30.5%), MDM2 (AMP) 6/36 (16.7%), ERBB2 3/36 (8.3%), PIK3cA 3/36 (8.3%), and ELF3 2/36 (5%) were seen in the highest frequency. 15/36 (41.6%) pts also consented for GT. Subgroup analysis revealed 4/15 (26.6%) pts with GA. Table 1 summarizes this subgroup. Conclusions: SA/GA in multiple genes including BRCA2, ERBB2/ELF3, and NTRK were observed. Also, novel GA in ATM (13%) and SA in MDM2 (AMP) (16.7%) were identified. Correlations of pathologic subtypes to clinical history, outcomes and mutations will be reported at the meeting. Further investigation of SA/GA in this disease is warranted given potential therapeutic and family screening implications. [Table: see text]

Abstract LB-B25: Preliminary phase I data comparing HuMab-5B1 (MVT-5873), a monoclonal antibody targeting sLea, as a single agent and in combination with first line nab-paclitaxel and gemcitabine in patients with CA19-9 positive pancreatic cancer

IntroductionMVT-5873, a fully human IgG1 monoclonal antibody (mAb), targets sialyl Lewis A (sLea), an epitope on CA19-9. CA19-9 is expressed in pancreatic (PDAC) and other GI cancers, plays a role in tumor adhesion and metastasis, and is a marker of an aggressive tumor phenotype. MVT-5873 is active as a single agent and in combination with nab-paclitaxel (nab-P) and gemcitabine (gem) in murine xenografts. MethodsSingle agent: for each 28-day treatment cycle, MVT-5873 was given IV every second week (Group 1) or weekly (Group 2) at doses ranging from 1 to 3 mg/kg. Combination with nab-P and gem: for each 28-day treatment cycle MVT-5873 was administered IV weekly (1.0mg/kg or 0.125mg/kg) followed by IV infusion of 125 mg/m2 of nab-P and then 1000mg/m2 gem, on day 1, 8 and 15 (Group 3). Eligible patients had recurrent progressive (single agent) or newly diagnosed (combination), locally-advanced or metastatic PDAC or other CA19-9+ malignancy and ECOG PS ≤1. Dose escalation followed a standard 3+3 design with a 10 patient expansion at the maximally tolerated dose (MTD). Trial endpoints include safety, MTD, dose limiting toxicities (DLT), pharmacokinetics (PK) and efficacy. Exploratory endpoints include changes in serum CA19-9 levels.ResultsAs of 7-September-2017, data are available for single agent N=32 in Groups 1 (N=9) and 2 (N=23) at 1, 2, 2.5 and 3 mg/kg and combination Group 3 (N=6) at 1.0 and 0.125mg/kg. DLTs of transient grade 3 elevations in AST, ALT, and total bilirubin were encountered in the single agent groups at 2, 2.5 and 3mg/kg in both single agent groups and in the combination group at 1mg/kg. Single agent liver function laboratory abnormalities typically emerged and resolved within a week of dosing although they were more persistent in the combination treated patients. Other toxicities associated with all groups included low grade GI toxicity (abdominal pain/cramps/diarrhea/nausea) and infusion reactions. Infusion reactions were mitigated with pre-medications and an increase in the infusion time. Combination DLTs for MVT-5873 at 1mg/kg included AST, ALT, and bilirubin elevations as well as neutropenia and pneumonitis resulted in significant dose de-escalation. MVT-5873 dosed at 0.125 mg/kg in combination was generally well tolerated. Single agent activity included SD of &gt;4 months in 5 of 32 of patients with an MTD established at 1 mg/kg. Combination activity at 0.125 mg/kg MVT-5873 with nab-P/gem included 2 PRs and 1 SD in 3 patients. Interestingly, sustained suppression below ULN of CA19-9 levels was observed in 3 of the 6 patients in the combination arm and &gt;95% CA19-9 reduction at the 0.125mg/kg combination dose. Dose escalation in this arm is in progress, and updated safety, PK/PD, and efficacy data will be presented.ConclusionsSingle agent MVT-5873 appears safe and tolerable at biologically active doses. DLTs included reversible liver function abnormalities. Determination of the MTD in combination with first line nab-P/gem is underway and preliminary response data are encouraging. Overall, the safety profile, efficacy, and reductions in serum CA19-9 levels over time support further development of MVT-5873 in this indication both as a single agent and in combination.

Citation Format: Eileen Mary O'Reilly, Judy Sing-Zan Wang, Kenneth H. Yu, Maeve Aine Lowery, Anna M. Varghese, Johanna C. Bendell, Erkut Hasan Borazanci, Hayley Estrella, Kimberly Fowler, Mariella Hoskins, Stephanie Bussen, Teresa J. Melink, Christine M. Kearns, H Toni Jun, Paul W. Maffuid, John C. Gutheil, Todd Michael Bauer. Preliminary phase I data comparing HuMab-5B1 (MVT-5873), a monoclonal antibody targeting sLea, as a single agent and in combination with first line nab-paclitaxel and gemcitabine in patients with CA19-9 positive pancreatic cancer [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr LB-B25.