Phase 2 study of carfilzomib for the treatment of patients with advanced neuroendocrine cancers.

Abstract

382 Background: Carfilzomib (CFZ) is an irreversible proteasome inhibitor (PI) that exhibits anti-proliferative and pro-apoptotic activity in solid and hematologic tumor cells i n vitro, and is US FDA approved for multiple myeloma. Proteasomes degrade cell cycle inhibitor proteins and inhibition of these proteins offers a novel therapy for the treatment of patients with neuroendocrine tumors (NET). This phase 2 study evaluated the efficacy of CFZ for patients with advance NETs. Methods: Pts with biopsy-proven, advanced, well-to-moderately differentiated NETs, including typical carcinoid and pancreatic islet cell tumors, were treated with CFZ 20 mg/m2 IV Days (D) 1 and 2, then 56 mg/m2 IV D 8, 9, 15, and 16 of Cycle (C) 1, followed by CZF 56 mg/m2 IV D 1, 2, 8, 9, 15, and 16 of C 2 and beyond. Pts continued study treatment (tx) until intolerable toxicity, disease progression, or withdrawal of consent. Restaging occurred every 3 cycles. The primary endpoint was overall response rate (ORR); secondary endpoints were disease control rate (DCR), progression free survival (PFS), and toxicity. Results: 62 pts were enrolled: median age 63 yrs, 61% female, 50% ECOG 0/50% ECOG 1. 65% of pts had carcinoid tumors and 35% of pts had pancreatic NET. The most common primary sites of disease were the pancreas (34%) and the small intestines (21%). 74% of pts had prior systemic therapy, 42% had prior surgery and 16% had prior radiotherapy. Median tx duration was 11 wks. At the time of data cutoff, 31% of pts remained on tx. 32% of pts discontinued due to progressive disease, 16% due AE, and 21% due to pt or physician decision. Two pts (3%) had a confirmed partial response (PR) and 1 pt (2%) had an unconfirmed PR; 4 ongoing patients have not yet been evaluated for response. The ORR was 3.23% (95% CI 0.4%, 11.2%), the DCR was 53.23% (CI 95% 40.1%, 66.0%), and median PFS was 8.1 months. The most frequently reported tx-related AEs were nausea (52%; Grade 3/4 [G3/4], 2%), fatigue (42%; G3/4, 3%), vomiting (36%; G3/4, 2%), and diarrhea (27%; G3/4, 5%). Conclusions: CFZ tx was well-tolerated in this pt population. Future plans will be determined once response data are available on all patients. Updated results will be presented. Clinical trial information: NCT02318784.