ASCO Annual Meeting
START trial keeps L-BLP25 immunotherapy alive in stage III NSCLC
AT THE ASCO ANNUAL MEETING 2013
Major finding: Median survival in patients who received initial concurrent chemoradiotherapy was 30.8 months with maintenance L-BLP25 vs. 20.6 months with placebo (HR, 0.78; P = .016).
Data source: Phase III trial of maintenance L-BLP25 immunotherapy in 1,239 patients with unresectable stage III non-small cell lung cancer.
Disclosures: START was supported by Merck KGaA. Dr. Butts reported a consultant/advisory role and honoraria from Merck KGaA and Merck Serono. Dr. Vansteenkiste reported a consultant/advisory role with Merck Serono and GlaxoSmithKline, and research support from Eli Lilly and AstraZeneca.
CHICAGO – Maintenance therapy with the investigational immunotherapy L-BLP25 offered no significant overall survival advantage in stage III unresectable non-small cell lung cancer in the phase III START trial.
In a modified intention-to-treat population of 1,239 patients, median overall survival was 25.6 months with L-BLP25 and 22.3 months with placebo (adjusted hazard ratio, 0.88; P = .123). Median follow-up was 39.9 months and 37.7 months, respectively.
Although the trial failed to meet its primary endpoint, the results were encouraging in patients receiving initial concurrent chemoradiotherapy, the largest subset of patients in the trial, Dr. Charles Butts said at the annual meeting of the American Society of Clinical Oncology.
Median survival in these 806 patients was 10.2 months longer with L-BLP25 (now known as Tecemotide) at 30.8 months vs. 20.6 months with placebo (HR, 0.78; P = .016).
Patients in all subgroups in the preplanned analysis appeared to benefit from maintenance L-BLP25, except those who had initial sequential chemotherapy/radiation therapy (19.4 vs. 24.6 months; HR, 1.12; P .38).
The secondary endpoints also significantly favored L-BLP25 over placebo for time to symptomatic progression (14.2 vs. 11.4 months; HR, 0.85; P = .023) and time to progression (10.0 vs. 8.4 months; HR, 0.87; P = .053), said Dr. Butts of the Cross Cancer Institute, University of Alberta, Edmonton.
"The treatment was well tolerated, and, certainly, further study is required to confirm these results," he said.
In a statement released by the study sponsor, Merck KGaA, Dr. Butts observed that concurrent chemoradiotherapy is the standard of care recommended for unresectable stage III NSCLC in U.S. and European guidelines, and said, "This is the first time that an antigen-specific cancer immunotherapy has shown this effect in a substantial subgroup of NSCLC patients who are usually only observed following chemoradiotherapy."
L-BLP25, formerly known as Stimuvax, targets the mucin1 (MUC1) cell surface–associated antigen, which is overexpressed and aberrantly glycolated in many epithelial tumors, particularly NSCLC. L-BLP25 appeared to confer a survival benefit to patients with localized stage III NSCLC in two earlier phase II trials.
Treatment in the phase III START (Stimulating Targeted Antigenic Responses to NSCLC) trial, however, was suspended for a median of 135 days in 531 patients after the Food and Drug Administration placed a clinical hold in 2010 on all L-BLP25 trials after a case of fatal encephalitis was reported in a patient with multiple myeloma in a phase II study and immune-related causality could not be excluded, Dr. Butts explained.