Based on the accelerated approval regulations, the FDA approved Keytruda for use in adult patients at a fixed dose of 200mg, while in pediatric patients at a dose of 2 mg/kg (up to 200 mg).
Keytruda is a humanized monoclonal antibody, which will enhance the ability of the body’s immune system to detect and fight tumor cells.
It can block the interaction between PD-1 and its ligands PD-L1 and PD-L2, helping to activate T lymphocytes that will affect both tumor cells and healthy cells.
The approval was based on data from the firm’s KEYNOTE-087 trial, which recruited up to 210 patients.
According to the firm, the trial showed an overall response rate (ORR) with Keytruda (200mg every three weeks) of 69% with a complete remission rate (CRR) of 22% and a partial remission rate (PRR) of 47%.
The patients in the multicenter, nonrandomized and open-label trial received Keytruda at a dose of 200mg every three weeks until unacceptable toxicity or documented disease progression, while up to 24 months in patients who did not progress.
Merck Research Laboratories president Roger Perlmutter said: “The results from KEYNOTE-087 showed that most patients with relapsed or refractory classical Hodgkin lymphoma responded to treatment with Keytruda, and 22 percent experienced complete remission.
“Today’s approval – the first for Keytruda in a hematologic malignancy – reinforces the hope that immunotherapy will prove useful in a wide variety of cancers.”
Image: Merck’s Keytruda. Photo: courtesy of Merck Sharp & Dohme Corp.