Faculty Bibliography

BACKGROUND:Olaparib is an oral inhibitor of polyadenosine 5'-diphosphoribose polymerization (PARP) that has previously shown signs of activity in patients with BRCA mutations and pancreatic ductal adenocarcinoma (PDAC). PATIENTS AND METHODS/METHODS:In this phase 1 dose-escalation trial in patients with unresectable PDAC, we determined the maximum tolerated dose (MTD) of olaparib (tablet formulation) in combination with irinotecan 70 mg/m2 on days 1 and 8 and cisplatin 25 mg/m2 on days 1 and 8 of a 28-day cycle (olaparib plus IC). We then studied the safety and tolerability of adding mitomycin C 5 mg/m2 on day 1 to this regimen (olaparib plus ICM). RESULTS:18 patients with unresectable PDAC were enrolled. The MTD of olaparib plus IC was olaparib 100 mg twice-daily on days 1 and 8. The addition of mitomycin C to this dose level was not tolerated. Grade ≥3 drug-related adverse events (AEs) were encountered in 16 patients (89%). The most common grade ≥3 drug-related toxicities included neutropenia (89%), lymphopenia (72%), and anemia (22%). Two patients (11%), both of whom had remained on study for more than 12 cycles, developed drug-related myelodysplastic syndrome (MDS). The objective response rate (ORR) for all evaluable patients was 23%. One patient who carried a deleterious germline BRCA2 mutation had a durable clinical response lasting more than four years, but died from complications of treatment-related MDS. CONCLUSIONS:Olaparib had substantial toxicity when combined with IC or ICM in patients with PDAC, and this treatment combination did not have an acceptable risk/benefit profile for further study. However, durable clinical responses were observed in a subset of patients and further clinical investigation of PARP inhibitors in PDAC is warranted. TRIAL REGISTRATION/BACKGROUND:This clinical trial was registered on ClinicalTrials.gov as NCT01296763.

Targeted therapies and immunotherapy have changed the face of multiple solid malignancies, including metastatic melanoma and lung cancer, but no such therapies exist for pancreatic ductal adenocarcinoma (PDAC) despite the knowledge of key mutations and an increasing understanding of the tumor microenvironment. Until now, most clinical studies have not been biomarker driven in this highly immunosuppressive and heterogeneous cancer. Ongoing basic and translational studies are better classifying the disease in hopes of identifying critical pathways that distinguish the unique PDAC subtypes, which will lead to personalized therapies. In this review, we discuss the current treatment options for metastatic pancreatic cancer and highlight current ongoing clinical trials, which aim to target the stroma and the immune microenvironment either alone or in combination with standard chemotherapy. Identifying biomarkers and key resistance pathways and targeting these pathways in a personalized manner in combination with chemotherapy are likely to yield a more immediate and durable clinical benefit.Clin Cancer Res; 23(7); 1670-8. ©2017 AACRSee all articles in thisCCR Focussection, "Pancreatic Cancer: Challenge and Inspiration."