Tasquinimod and survival in men with metastatic castration-resistant prostate cancer: Results of long-term follow-up of a randomized phase II placebo-controlled trial.

Abstract

4550 Background: Tasquinimod (T) is an oral quinoline-3-carboxamide derivative that binds S100A9 protein and has preclinical anti-angiogenic and anti-tumor activity. Between 12/07-6/09, 201 (134 T, 67 Placebo (P)) men with metastatic CRPC were randomized and received treatment once-daily at an initial dose of 0.25 mg/day escalated to 1.0 mg/day over 4 weeks. Placebo patients could cross over to T after 6 months or at disease progression. The primary endpoint of improved PCWG2 criteria-defined progression at 6 months was met (69 vs. 37% of patients (T/P) were progression free) with PFS of 7.6 vs. 3.3 months for pts on T vs. P1 with acceptable toxicity. This abstract provides the first analysis on symptomatic progression, overall survival (OS) as well as a multivariate analysis for PFS and OS. Methods: Survival data were collected between June 2011 and January 2012 with a median time to censoring of 32 months. Survival data was also evaluated in an exploratory multivariate model of known prognostic factors in CRPC. Results: An imbalance of several baseline prognostic criteria favored placebo (e.g. baseline PSA of 29 vs. 19 (T/P)) (JCO 2011;20:4022). Time to symptomatic progression was longer in T treated patients (p=0.039, HR=0.42). Record of death (97 events) or survival >13 months was documented in 182 patients. Median time to death was 34.2 vs. 30.2 months (T/P). Median time to death in the PCWG2 bone-metastatic subgroup (N=92/44) was 34.2 vs. 25.6 months. A multivariate analysis of known prognostic factors including PSA, LDH, PSA kinetics, and hemoglobin demonstrated an adjusted HR for PFS of 0.54 (95% CI 0.37,0.81) and OS of 0.72 (95% CI 0.46,1.12) in the total population and 0.63 (95% CI 0.37,1.07, n=136) in the bone-metastatic group. Conclusions: OS observed after tasquinimod treatment is longer than previously reported in this patient population. The current exploratory data indicates that the prolongation in PFS observed with tasquinimod treatment may lead to a survival advantage in men with metastatic CRPC. A phase III placebo-controlled study (NCT01234311) is ongoing in men with bone-metastatic CRPC powered to detect an OS improvement.