24 February 2020 - - The US Food and Drug Administration has issued a Complete Response Letter regarding US-based pharmaceutical company Merck's (NYSE: MRK) supplemental Biologics License Applications (sBLAs) seeking to update the dosing frequency for Keytruda (pembrolizumab), Merck's anti-PD-1 therapy, to include a 400 mg dose infused over 30 minutes every-six-weeks option in multiple indications, the company said.

The submitted applications are based on pharmacokinetic modeling and simulation data presented at the 2018 ASCO annual meeting.

These data supported the European Commission approval of 400 mg Q6W dosing for Keytruda monotherapy indications on March 28, 2019.

Merck is reviewing the letter and will discuss next steps with the FDA.

Keytruda is an anti-PD-1 therapy that works by increasing the ability of the body's immune system to help detect and fight tumor cells.

Keytruda is a humanised monoclonal antibody that blocks the interaction between PD-1 and its ligands, PD-L1 and PD-L2, thereby activating T lymphocytes which may affect both tumor cells and healthy cells.

Merck has the industry's largest immuno-oncology clinical research program.

There are currently more than 1,050 trials studying Keytruda across a variety of cancers and treatment settings.

The Keytruda clinical programme seeks to understand the role of Keytruda across cancers and the factors that may predict a patient's likelihood of benefitting from treatment with Keytruda, including exploring several different biomarkers.