Recent data from the Phase III KEYNOTE-604 trial has revealed mixed results for MSD’s Keytruda (pembrolizumab).

The cancer blockbuster in combination with chemotherapy significantly improved progression-free survival (PFS) compared to just chemo as a first-line treatment for patients with extensive-stage small-cell lung cancer (SCLC).

The anti-PD-1, however, missed the mark in terms of the study’s other dual primary endpoint of overall survival (OS), as the “results did not meet statistical significance per the pre-specified statistical plan.”

As a side, the safety profile in the trial was consistent with that observed in previously reported studies.

The trial enrolled 453 patients with newly diagnosed extensive-stage SCLC who had not previously received systemic therapy, and were randomised to receive either Keytruda or placebo, both in combination with etoposide and investigator’s choice of platinum chemotherapy.

The results show “potential” for the drug to extend its use in to SCLC, said Dr Roy Baynes, chief medical officer at MSD, who also said the company “sincerely thanks the patients and investigators for their participation in this study”, whilst reassuring that it is “committed to helping patients who face difficult-to-treat types of lung cancer.”

Last year the US Food and Drug Administration (FDA) approved Roche’s Tecentriq (atezolizumab) in combination with chemo for extensive-stage SCLC, making it the first cancer immunotherapy authorised in this indication.

Back in November last year the European Commission approved the therapy as monotherapy or as part of a combination, for the first-line treatment of patients with metastatic or unresectable recurrent head and neck squamous cell carcinoma (HNSCC).

Lung cancer is the leading cause of cancer death worldwide, with more people dying of lung cancer each year than colon and breast cancers combined. SCLC accounts for about 10 to 15% of all lung cancers.