GALAXY-1: Randomized phase II study of docetaxel with or without ganetespib in advanced lung adenocarcinoma: Results in biomarker sub-groups and all adenocarcinoma patients.

Background: Ganetespib (G) is a highly potent 2nd-generation Hsp90 inhibitor showing synergistic activity with docetaxel (D) in NSCLC xenografts. G has a favorable clinical safety profile and has shown single-agent clinical activity in NSCLC patients with tumors harboring EML4-ALK translocations and KRAS mutations (mKRAS). Methods: We conducted a randomized, international open-label Phase 2 study of D with or without G in patients with advanced lung adenocarcinoma, one prior systemic therapy, and ECOG PS 0/1. D was given at 75 mg/m2 on Day 1 of a three-week cycle in both arms. In the combination arm, G was given at 150 mg/m2 on Days 1 and 15. The co-primary endpoints were PFS in patients with elevated LDH (eLDH) levels, or tumors harboring KRAS mutation. Key secondary endpoints were OS and PFS in all adenocarcinoma patients. Target enrollment was 240 adenocarcinoma patients, including 120 eLDH and 80 mKRAS patients. The study was initiated in all NSCLC patients and amended to include only those with adenocarcinoma histology. Results: Enrollment of 252 adenocarcinoma patients completed in November 2012; enrollment of eLDH (total N=112) and mKRAS (total N= 86) patients completed in May 2013. In all adenocarcinoma patients (N=252), baseline characteristics were balanced between the two arms (median age 60 years, males 56%, PS 0 41% and never-smokers 25%). Median numbers of cycles delivered were 6 and 4 for D+G and D, respectively. Grade 3/4 adverse events for the D+G and D alone arms were: neutropenia 37% vs. 38%; fatigue 6% vs. 3%; anemia 8% vs. 2%; diarrhea 3% vs. 0; fever with neutropenia 11% vs. 2%. A pre-specified analysis was conducted in May 2013. PFS HR for eLDH population (N=76) was 0.88 (90% CI: 0.57, 1.36, p=0.310); OS HR was 0.63 (90% CI: 0.40, 0.99, p=0.046). PFS HR for mKRAS population (N=63) was 0.83 (90% CI: 0.51, 1.37, p=0.271); and OS HR was 0.85 (90% CI: 0.48, 1.50, p=0.313). OS HR in the all adenocarcinoma population was 0.82 (90% CI: 0.62, 1.09, p=0.082), and the PFS HR was 0.84 (90% CI: 0.65, 1.07, p=0.038). For patients that were enrolled >6 months after diagnosis of advanced NSCLC (N=176), a pre-specified stratification factor, the OS HR was 0.61 (90% CI: 0.43, 0.87, p=0.0093), and the PFS HR was 0.61 (90% CI: 0.45, 0.83, p=0.0041). Final data analysis is expected by end of September 2013. Updated PFS and OS results for all populations will be presented at the meeting. Conclusion: Survival improvement was noted in all adenocarcinoma patients with the addition of ganetespib to docetaxel. The maximal benefit was achieved in patients with eLDH and those diagnosed with advanced NSCLC >6 months prior to study entry.