MSD’s Prevymis has not won the support of NHS cost regulators for preventing cytomegalovirus (CMV) reactivation and disease in prone adults who have received an allogeneic haematopoietic stem cell transplant (HSCT).

Around 50-80 percent of adults in the UK are thought to be infected with CMV, which can remain in the body in an inactive or latent state, potentially becoming reactivated if the immune system is compromised.

As such, CMV infection is a common complication in patients taking immunosuppressants as part of a HSCT regimen, and reactivation of the virus after transplant is linked with serious complications and increased mortality.

Prevymis (letermovir), a first-in-class antiviral drug that inhibits CMV replication, was approved for use in Europe in January this year. This followed Phase III data showing that significantly fewer patients taking the drug (38 percent) - compared to those given a placebo (61 percent) - developed clinically significant CMV infection, discontinued treatment or had missing data through Week 24 post-HSCT.

However, in draft guidelines, the National Institute for Health and Care Excellence noted that while clinical trial evidence shows that Prevymis is indeed effective in reducing CMV infection and reduces the need for pre-emptive therapy, whether it reduces mortality from CMV disease is uncertain.

Also, there are concerns about how relevant the trial data are to NHS clinical practice, it said.

The most plausible cost-effectiveness estimates are above £20,000 per quality-adjusted life year (QALY) gained and higher than £30,000 per QALY gained in some scenarios, and so the drug cannot be recommended for NHS use, the Institute noted.