Brief report: a phase II "window-of-opportunity" frontline study of the MTOR inhibitor, temsirolimus given as a single agent in patients with advanced NSCLC, an NCCTG study.

BACKGROUND: In an effort to evaluate the single agent activity of temsirolimus in previously untreated non-small-cell lung cancer, the North Central Cancer Treatment Group undertook a frontline "window-of-opportunity" study. METHODS: Patients received 25 mg of temsirolimus administered intravenously as a weekly 30 minute infusion, on a 4-week cycle. Based on a two-stage Fleming design, the treatment would be promising if at least four of the first 25 evaluable patients in stage I or at least six of the 50 evaluable patients at the end of stage II have a confirmed response. Fresh tumor biopsies were obtained to evaluate predictive markers of temsirolimus activity. RESULTS: A total of 55 patients were enrolled with 52 patients being evaluable. The median age was 64 years. Adverse events (grade 3/4) occurring in 33 patients included dyspnea (12%), fatigue (10%), hyperglycemia (8%), hypoxia (8%), nausea (8%), and rash/desquamation (6%). The clinical benefit rate was 35% with four patients achieving a confirmed partial response and 14 patients with stable disease for 8 weeks or more. The 24-week progression-free survival rate was 25%. Median progression-free survival and overall survival were 2.3 and 6.6 months, respectively. Expression of p70s6 kinase, phospho-p70s6 kinase, Akt, phospho-Akt, and phosphatase and tensin homolog mutation did not correlate with clinical outcome. CONCLUSIONS: Temsirolimus given as a single agent in frontline therapy in patients with non-small-cell lung cancer was tolerable and demonstrated clinical benefit but did not meet the primary objective in this study. Patient selection will be needed to enhance the efficacy.

Endpoints in phase II trials for advanced non-small cell lung cancer.

INTRODUCTION: We investigated the relationships between progression-free survival (PFS), response, confirmed response, and failure-free survival (FFS) with overall survival (OS) to assess their suitability as primary endpoints in phase II trials for advanced non-small cell lung cancer. METHODS: Individual data of 284 patients from four phase II trials were pooled. Progression status and response were modeled as time dependent variables in a multivariable (adjusted for baseline age, gender, stage, and performance status) Cox proportional hazards model for OS, stratified by trial. Subsequently, Cox proportional hazards models were used to assess the impact of PFS, response, confirmed response, and FFS on subsequent survival, using landmark analysis at 8, 12, 16, 20, and 24 weeks. Model discrimination was evaluated using the concordance index (c-index). RESULTS: The overall median OS, PFS, and FFS were 9.6, 3.7, and 2.8 months, and the response and confirmed response rates were 21 and 15%, respectively. Both progression status and response as time dependent covariates were significantly associated with OS (p < 0.0001; p = 0.009). PFS and FFS at 12 weeks significantly predicted for subsequent survival with the strongest c-index and hazard ratio combination in landmark analyses (hazard ratio, c-index: PFS: 0.39, 0.67; FFS: 0.37, 0.67). The c-indices for response and confirmed response were low (0.59-0.60), indicating their inability to sufficiently discriminate subsequent patient survival outcomes. CONCLUSIONS: FFS or PFS at 12 weeks is a stronger predictor of subsequent patient survival compared with tumor response and should be routinely used as endpoints in phase II trials for advanced non-small cell lung cancer.