START: A phase III study of L-BLP25 cancer immunotherapy for unresectable stage III non-small cell lung cancer.

7500 Background: L-BLP25 is a MUC1 antigen specific cancer immunotherapy. We report results from the phase III START study of L-BLP25 in patients (pts) not progressing after primary chemoradiotherapy (CRT) for stage III NSCLC. Methods: From Jan 2007 to Nov 2011, 1513 pts with unresectable stage III NSCLC that did not progress after CRT (platinum based chemo and ≥50 Gy) were randomized (2:1; double-blind) to L-BLP25 (806 µg lipopeptide) or placebo (PBO) SC weekly x 8 then Q6 weeks until disease progression or withdrawal. Cyclophosphamide 300 mg/m2 x 1 or saline was given 3 days prior to first L-BLP25/PBO dose. Primary endpoint was overall survival (OS). Results: The primary analysis population (n=1239) was defined prospectively to try to account for a clinical hold by excluding pts randomized 6 months (m) before the hold. Arms were balanced for baseline characteristics. Median age was 61 y; 38.2% had stage IIIA and 61.3% IIIB; 65% had concurrent and 35% sequential CRT. Median OS was 25.6 m with L-BLP25 vs....