Merck & Co's Keytruda has become the first drug in the PD-1/PD-L1 inhibitor class to be approved for first-line treatment of non-small cell lung cancer (NSCLC), setting the stage for acceleration in its use.
The US FDA approved the drug two months ahead of schedule for patients with advanced NSCLC whose tumours express high levels of PD-L1 (i.e. with 50% or more of the cells producing the biomarker).
In the KEYNOTE-024 trial, Keytruda improved both progression-free survival and overall survival compared to platinum-based chemotherapy in these patients.
The green light gives Merck another opportunity to gain ground on its arch-rival Bristol-Myers Squibb, whose PD-1 inhibitor Opdivo (nivolumab) is currently outselling Keytruda by a factor of three. In the first six months of the year sales of Opdivo came in at $1.54bn, with Keytruda bringing in $563m.
Keytruda, Opdivo and Roche's new PD-L1 inhibitor Tecentriq (atezolizumab) are all approved for second-line treatment after chemotherapy in NSCLC patients, but claiming the first-line indication is expected to be crucial for future dominance in the big NSCLC market.
BMS' drug performed worse than chemotherapy in the CheckMate-026 trial, and initially it was thought that the company's 'all-comer' strategy of enrolling NSCLC patients with both high and low PD-L1 expression may have been the cause. A closer look at the data gave no comfort however, with the drug failing to show any effect regardless of the PD-L1 expression status of patients.
Opdivo's stumble means Keytruda will likely be the only immuno-oncology option for previously-untreated NSCLC until Roche completes its phase III first-line programme for Tecentriq, which is due to generate its first results in 2018.
Roche is also testing Tecentriq in combination with chemotherapy in NSCLC patients with high and low PD-L1 expression levels, while BMS is hoping that an all-comer trial looking at the combination of its two current immuno-oncology drugs - Opdivo and CTLA4 inhibitor Yervoy (ipilimumab) - could tip the balance in its favour once again.
Merck will make hay in the meantime, and with PD-L1 testing becoming more common in the first-line setting there could be a pull-through effect for Keytruda into second-line treatment, further lessening Opdivo's advantage in this form of cancer.
Keytruda's competitive position in second-line has also been improved by another FDA approval, this time for labelling that will make patients who have failed to improve with chemotherapy eligible for pembrolizumab even if their tumours produce a low level of PD-L1.