Phase II trial of veliparib (V) in patients (pts) with previously treated BRCA or PALB2-mutated (mut) pancreas adenocarcinoma (PC).
358 Background: BRCA1, BRCA2, and PALB2 germline mutations are associated with an increased risk of PC. Other BRCA-associated cancers have demonstrated increased sensitivity to PARP inhibitors (PARPi) and early trials have shown activity of PARPi in untreated BRCAmut PC. We evaluated theactivity of V in patients with previously treated BRCA/PALB2mutPC. Methods: Eligibility: BRCA1/2, or PALB2mutPC, at least 1 and up to 2 prior treatment regimens, measurable stage III/IVPC; ECOG 0-1. Treatment Plan: V 300mg BID (N= 3 pts), then V 400mg BID day1- 28. Primary endpoint: RECIST 1.1 response rate (RR). Statistical plan: Single-arm, non-randomized, open-label, phase II, two-stage design, unacceptable RR 10%, promising 28%, type I, II error rates 10%. Secondary endpoints: progression-free survival (PFS), duration of response, overall survival, safety, tolerability and archival tumor analyses. Results: Between 05/12 and 12/13, N= 16 enrolled. Male= 8, Female= 8. Median age= 52 years (range 43- 77). BRCA1 mut=5. BRCA2 mut=11. N= 1AJCC stage III PC, N= 15 AJCC stage IV PC. N= 8 and N= 8 (50%) had 1 and 2 prior lines of therapy respectively. N= 13 (81%) received prior platinum therapy. Response: N= 1 unconfirmed PR (PR at 4 months (mo), POD at 6 mo), N= 4 stable disease (SD), N= 10 progressive disease (PD); N= 1 inevaluable (12 days of V only due to disease-related complications). Median PFS was 52 days (range 12 to 423). Three pts treated at 400mg V were dose-reduced for toxicity. Six pts had V related grade 3 toxicity including fatigue (N=3), hematologic (N=2) and nausea (N=1). No therapy-related grade 4-5 toxicities were observed. Conclusions: V was well tolerated. While no confirmed partial responses were observed, single-agent activity of V in previously treated PC was noted, and N= 4 (25%) remained on study with SD for ≥ 4mo (4, 6, 6, 9 mo). A randomized phase II trial evaluating cisplatin,gemcitabine +/- V is underway in untreated BRCA/PALB2mutPC (NCT01585805). Results of correlative studies will be presented. Acknowledgements: Lustgarten Foundation. NCI.AbbVie. Clinical trial information: NCT01585805.