GlaxoSmithKline (GSK) said it was 'disappointed' after having to call an end to its clinical trial for its treatment for non-small cell lung cancer (NSCLC).The MAGRIT trial, a phase three trial of its MAGE-A3 antigen-specific cancer immunotherapeutic in NSCLC patients, has been ended as GSK couldn't identify a sub-population of gene-signature positive NSCLC patients that may benefit from the treatment.The company had announced last month that the first and second co-primary endpoints of the trial did not significantly extend disease-free survival when compared to a placebo. The MAGRIT trial then continued to investigate a third co-primary endpoint but analysis of the results found that this "is not feasible due to an insufficient treatment effect"."While we are extremely disappointed to learn that this trial did not have a positive outcome for the patients who participated in this trial, we are very grateful to its participants," said Vincent Brichard, Senior Vice-President and Head of Immunotherapeutics at GSK Vaccines. "We hope that the data generated in this trial will advance our understanding of the science of immunotherapeutics, and ultimately towards development of new therapies."The stock was down 0.25% at 1,589p in early trading on Wednesday.BC