GlaxoSmithKline has been forced to halt a Phase III trial assessing its MAGE-A3 cancer immunotherapeutic in patients with non-small cell lung cancer (NSCLC).

High hopes for the experimental immunotherapy - designed to help patients stave off the return of the disease after treatment - came after it emerged that researchers would not be able to identify a subset of patients who may benefit from its therapy, hot on the heels of other disappointing data.

Last month it was revealed that the MAGRIT trial failed to meet its primary and secondary endpoints after the treatment failed to significantly extend disease-free survival (DFS) when compared to placebo, in either the overall MAGE-A3 (a specific tumour antigen) positive population or in MAGE-A3-positive patients who did not receive chemotherapy.

Disappointingly, the third co-primary endpoint, hoping to show DFS in a genetically determined sub-population, could not be met because an insufficient treatment effect meant that researchers could not identify these patients.

There were no safety concerns raised by the data, but GSK said it is "extremely disappointed" that the trial did not have a positive outcome for patients.

The firm is, however, pushing on with another ongoing Phase III clinical trial (DERMA) assessing whether a gene signature could identify a sub-population of melanoma patients that would benefit from the same MAGE-A3 cancer immunotherapeutic.

The failure of the drug in lung cancer is another blow for the drug giant, which just yesterday announced that it is pulling back an application in Europe to market Votrient for ovarian cancer.