Merck tees up Prevymis filing in kidney transplant recipients after phase 3 trial win

Since it hit the market in 2017 to prevent cytomegalovirus (CMV) infection in stem cell transplant patients, Merck’s Prevymis has racked up steadily increasing sales.

With results from a phase 3 study—presented Saturday at IDWeek 2022—Merck has a chance to expand the medicine's reach to kidney transplant recipients.

In testing Prevymis against Roche’s standard of care treatment Valcyte in kidney transplant recipients, Merck's drug showed comparable efficacy and a significantly better safety profile. The drugs were provided for 200 days after transplant, with follow-up at 52 weeks, the company said.

Of 601 patients deemed at high risk for CMV, 10.4% of those on Prevymis were infected after 52 weeks versus 11.8% of those who were given Valcyte.

As for the incidence of bone marrow toxicity—as measured by rates of leukopenia or neutropenia—26% of those on Prevymis showed myelotoxicity versus 64% on Valcyte, Merck said.

Roche's Valcyte "has been the most commonly used drug for CMV prophylaxis in this setting, but myelotoxicity (especially neutropenia and leukopenia) is an important limitation of this drug," Ajit Limaye, M.D., director of the Solid Organ Transplant Infectious Disease Program at the University of Washington School of Medicine, said in a release.

"Myelotoxicities can be difficult to manage in patients who are already receiving complex treatment regimens with other drugs that also have bone marrow suppressive effects," Limaye added.

Merck said it plans to submit a supplemental new drug application to the FDA by the end of this year.

Over the last three years, sales of Prevymis have escalated from $165 million (2019) to $281 million (2020) to $370 million last year.

Each year, roughly 200,000 transplants are executed worldwide, with nearly a quarter of recipients developing CMV infection. There are two other antivirals on the market to prevent infection after a transplant. In November of last year, Takeda scored FDA approval for Livtencity, which has a different mechanism of action to prevent CMV.