Bortezomib + gemcitabine (Gem)/carboplatin (Carbo) results in encouraging survival in advanced non-small cell lung cancer (NSCLC): Results of a phase II Southwest Oncology Group (SWOG) trial (S0339)

Abstract

7017 Background: Bortezomib (PS-341), a small molecule proteasome inhibitor, has single agent activity in NSCLC and potentiates Gem/Carbo in pre-clinical models in a sequence-specific manner (Mortensen, Cancer Chem Pharm, 2004). A phase I trial of Gem/Carbo + PS-341 in patients (pts) with advanced NSCLC yielded an encouraging response rate of 48%. Here we describe the results of a SWOG phase II study of this regimen in advanced NSCLC. Methods: 114 eligible chemonaive stage IV and selected stage IIIB (pleural effusion) NSCLC pts received Gem 1000 mg/m2 on days 1, 8 and Carbo AUC 5 on day 1, followed 1 hour later by PS-341 1.0 mg/m2 on days 1, 4, 8, 11, with cycles repeated every 3 weeks. Non-progressing pts could continue PS-341 alone after 4 cycles. Results: Pt characteristics: Median age: 64 years; Sex M/F = 68/46; Performance status 0/1 = 50/64; stage IIIB/IV = 13/101. Response rate: 20% (95% CI 13–29%); 66% (95% CI 56–75%) had stable disease. At a median follow-up of 13 months, progression free and median survival times were 5 months (95% CI 3.5–5.3) and 11 months (95% CI 8.2–12.5). One-year survival was 46% (95% C.I. 37–55%). Most common grade 3/4 toxicities: neutropenia (52%), thrombocytopenia (63%), and fatigue (13%). Ongoing correlative studies are examining markers of proteasome inhibition (Bcl2 family, NFKB, IKB) and hypoxia (PAI-1, VEGF, OPN, HIF-1) in tumor tissue and surrogate specimens. Conclusions: The 11 month median survival achieved with the addition of PS-341 to Gem/Carbo in this phase II study is unprecedented in prior SWOG trials in advanced NSCLC, and does not appear to be explained by altered patient characteristics. The toxicity profile of this regimen is favorable. A phase III trial of Gem/Carbo ± Bortezomib in advanced stage NSCLC is under development. Supported by CA38926, CA32102. No significant financial relationships to disclose.