A Randomized, Placebo-Controlled, Phase 1b/2 Study of Rilotumumab or Ganitumab in Combination With Platinum-Based Chemotherapy as First-Line Treatment for Extensive-Stage Small-Cell Lung Cancer

Abstract

Introduction/background: In this randomized, double-blind, placebo-controlled phase 1b/2 study we assessed the efficacy/safety of rilotumumab or ganitumab combined with etoposide and carboplatin or cisplatin as first-line treatment in patients with extensive stage small-cell lung cancer (ES-SCLC).

Patients and methods: In the phase 1b study, patients received rilotumumab 15 mg/kg or ganitumab 18 mg/kg with etoposide and carboplatin or cisplatin. In the phase 2 study, patients were randomly assigned 1:1:1 to receive placebo, rilotumumab, or ganitumab with etoposide and carboplatin or cisplatin. Chemotherapy was administered for ≤ 6 cycles; rilotumumab, ganitumab, or placebo was then continued as maintenance therapy. The primary end points were incidence of dose-limiting toxicities (DLTs; phase 1b) and overall survival (OS; phase 2). Secondary end points included progression-free survival (PFS) and safety.

Results: In the phase 1b study (n = 28), 1 patient treated with ganitumab experienced a DLT (Grade 4 neutropenia/thrombocytopenia lasting ≥ 7 days). In the phase 2 study, 185 patients were enrolled (placebo, n = 61; rilotumumab, n = 62; ganitumab, n = 62). Median OS was 10.8, 12.2 (hazard ratio [HR], 0.84; 95% confidence interval [CI], 0.56-1.25; P = .384), and 10.7 (HR, 0.95; 95% CI, 0.63-1.41; P = .787) months, in placebo, rilotumumab, or ganitumumab arms, respectively. Median PFS was 5.4, 5.4 (HR, 1.05; 95% CI, 0.71-1.54; P = .797), and 5.5 (HR, 1.05; 95% CI, 0.72-1.55; P = .780) months, respectively. Adverse events resulting in treatment discontinuation occurred in 11 (19%), 10 (16%), and 7 (12%) patients, respectively. Serum biomarker analysis showed improved survival for patients with baseline hepatocyte growth factor levels below the median in the rilotumumab arm.

Conclusion: Although the combination of rilotumumab or ganitumab with chemotherapy was tolerable, overall outcomes were not improved in patients with ES-SCLC.

Keywords: Clinical trial; Hepatocyte growth factor; Insulin-like growth factor-1 receptor; MET; Small-cell lung carcinoma.