GSK posts middling data from PD-1 Tesaro buyout drug

GlaxoSmithKline has posted some updated though underwhelming and “clinically meaningful” data from a PD-1 inhibitor it got via its $5 billion Tesaro buyout.

The drug, dostarlimab, was originally developed by Anaptysbio and partnered with Tesaro, with the British Big Pharma inheriting that deal and drug when it bought Tesaro last year.

It’s a checkpoint inhibitor targeting PD-1 and is hardly cutting-edge these days as, if it were to gain approval, it would be the seventh drug of its kind to hit the market.

The data out from the GARNET test are an “updated analysis,” according to GSK, and include women with recurrent or advanced endometrial cancer who have progressed on or after platinum-based chemotherapy.

The full details are not yet out, but the pharma said its drug had “provided clinically meaningful results” in women with recurrent or advanced mismatch repair-deficient (dMMR) endometrial cancer who progressed on or after a platinum-based regimen. It did not say whether it was statistically significant.

The primary endpoints of the 71-patient trial were confirmed objective response rate (ORR) and duration of response (DoR), and the data break down like this: Treatment with dostarlimab showed an ORR of 42% and a disease control rate of 58%, but, overall, just 13% of patients had a complete response and 30% of patients had a partial response.

GSK said at the time of data cutoff, with a median follow up of 11.2 months, the median DoR had not been reached. The safety of the drug was relatively clean, with no deaths in the test.

Axel Hoos, M.D., senior vice president and head of oncology R&D at GSK, said: “We are committed to developing medicines for patients who face high unmet medical need. We believe in the clinical potential of dostarlimab for women with advanced or recurrent dMMR endometrial cancer who urgently need additional treatment options for this incurable disease.”

A BLA for the drug was submitted to the FDA a few months back, although we don’t yet know whether it’s been accepted nor its PDUFA date.  

The data have been accepted as a late-breaking abstract and presented as a webinar as part of the Society of Gynecologic Oncology 2020 virtual congress.

The drug is also being tested across a series of other cancers in different trials.