GSK’s Phase III Cancer Immunotherapeutic Study Misses First Co-Primary Endpoints
Agenus Inc. announced that GlaxoSmithKline’s MAGRIT i study, a Phase 3 randomized, blinded, placebo-controlled MAGE-A3 ii cancer immunotherapeutic trial in non-small cell lung cancer patients, which contains Agenus’QS-21 Stimulon ® adjuvant, did not meet its first or second co-primary endpoint. The study did not significantly extend the disease-free survival (DFS) iii period when compared to placebo in the overall MAGE-A3 positive patients or patients who did not receive chemotherapy.
GSK announced that it will continue the study until an analysis of the third co-primary endpoint is complete. The third co-primary endpoint is based on predefined criterion that was discussed with regulatory authorities. This analysis is based on gene signature and designed to prospectively identify MAGE-A3 positive patients who may benefit more from treatment. If further analysis shows that the predefined gene signature subset data are successful, there is the potential for regulatory filing. GSK anticipates that these data should be available in 2015. Until then, GSK will remain blinded to all safety and efficacy data.
The Independent Data Monitoring Committee for the MAGRIT study indicated that a review of the safety information raised no specific concern for the continuation of the trial.
About GSK’s MAGRIT Program
In this study, patients were given up to 13 intramuscular injections of either the MAGE-A3 immunotherapeutic or placebo over a period of 27 months.
GSK currently remains blinded to further details of the analysis of the first two co-primary endpoints in order to allow for the unbiased generation of a mathematical model to assess the third co-primary endpoint iv, which is expected to be known in 2015. GSK is also continuing to evaluate whether a gene signature can identify a population that would benefit from the same investigational MAGE-A3 cancer immunotherapeutic in DERMA, another Phase 3 trial in melanoma, which reported on the first co-primary endpoint in September 2013.
i A double-blind, randomised, placebo-controlled Phase III trial to assess the efficacy of recMAGE-A3 + AS15 antigen-specific cancer immunotherapeutic as adjuvant therapy in patients with MAGE-A3 positive NSCLC (MAGRIT, NCT00480025).
ii MAGE-A3 cancer immunotherapeutic consists of recombinant MAGE-A3 protein and a novel immunostimulant AS15 (a combination of QS-21 Stimulon ® adjuvant, monophosphoryl lipid A, and CpG7909, a TLR-9 agonist, in a liposomal formulation).
iii DFS is defined as the time from randomization to the date of first recurrence of the disease or death, whichever comes first.
iv Access to a proportion of the data (the training set) will allow for the unbiased generation of a mathematical model to assess the third co-primary endpoint in the remainder of the data (the test set).