Roche has presented impressive new data for its marketed antiviral Valcyte in the wake of the failure of a potential rival product, ViroPharma’s maribavir, in a late-stage study.

The Swiss major has that a Phase III study investigating extended preventative with Valcyte (valganciclovir) met its primary endpoint of reducing the number of kidney transplant patients who develop cytomegalovirus disease within the first year, post-transplant. Valcyte is currently licensed for the prevention of CMV disease in high-risk kidney, heart, and kidney-pancreas transplant patients and is administered for up to 100 days after the operation.

Now, findings from the new study (NT18435) show that treatment with Valcyte for 200 days further reduced the risk of CMV disease without increasing the risk of infection after stopping therapy, the company said. Roche quoted primary investigator of the study Atul Humar (University of Alberta, Canada), as noting that Valcyte “ is considered the gold-standard anti-CMV medication for transplant patients, and the fact that this study has shown improved protection from CMV by extending the course of prophylaxis is compelling news”.

Dr Humar added that CMV is the most common viral infection in transplant patients and “it can ‘lie dormant’ leaving high risk patients more vulnerable to infection for longer than was previously thought, placing the new organ and patient at risk”. He hopes that the benefits of 200-day prophylaxis with Valcyte “will translate into tangible improvements in patient care”.

The latest findings came days after ViroPharma stopped a Phase III trial of its experimental compound maribavir. The drug had failed to show any effect compared with placebo in reducing CMV in stem cell transplant patients.

The disappointing maribavir data resulted in ViroPharma stock losing more than 50% of its value.