1210 Long-Term Efficacy and Safety of L-BLP25 Vaccine in a Multi-Centre Open-Label Study of Patients with Unresectable Stage III NSCLC

Introduction L-BLP25 (Stimuvax®) is an antigen-specific cancer immunotherapeutic agent targeting the mucin 1 tumour-associated antigen. Phase IIb data suggest prolonged overall survival with L-BLP25 when administered after completion of chemoradiotherapy for locally advanced non-small-cell lung cancer (NSCLC; non-significant). This study was initiated in April 2005 to obtain safety data when modifications of the adjuvant component of the immunotherapeutic were performed. Here we report an updated analysis of long-term data based on the cut-off date 18 May 2011. Methods The primary objective of this open-label phase II study was to evaluate the safety of the new formulation of L-BLP25 in patients with unresectable stage IIIA/B NSCLC, with a secondary objective of assessment of survival time. Following completion of initial chemoradiotherapy, patients with stage III NSCLC received treatment with L-BLP25 starting with weekly injections over 8 weeks, followed by injections given every 6 weeks from week 13 onwards until disease progression. A single low dose of intravenous cyclophosphamide 300 mg/m2 (maximum 600 mg) was given 3 days before first vaccination. Results Twenty-two patients were enrolled. After a median follow-up of 70.3 months (median treatment duration 9.9 months [range, 1–73]), median survival time was 51.9 months (95%CI, 17.5, not estimable [NE]) and median progression-free survival was 31.4 months (95%CI, 5.7, NE). Five-year survival was 50% (95%CI, 29–71%); previously reported 1- and 2-year survival rates, 82% (95%CI, 66–98%) and 64% (95%CI, 44–84%), respectively. Four patients survived more than 72 months. Safety findings were consistent with previous reports; adverse events (AEs) consisted mainly of fatigue (59%), injection-site reactions (55%) and mild-to-moderate influenza-like illness. Two serious treatment-emergent AEs were assessed as being treatment-related: cholecystitis and pneumonia. Conclusions Long-term follow-up of this small patient population provides encouraging survival data for L-BLP25 maintenance therapy in stage III NSCLC. Long-term safety data were consistent with previous reports and did not reveal any new safety issues. Disclosure C. Butts: Charles Butts has provided consultancy and served on Speakers' Bureaux for Merck Serono. A. Maksymiuk: Andrew Maksymiuk has some stock shares in Merck Canada (