Bayer halts vilaprisan drug trials due to toxicology data

The logo of Bayer AG is pictured at the Bayer Healthcare subgroup production plant in Wuppertal, Germany February 24, 2014. REUTERS/Ina Fassbender/File Photo

FRANKFURT (Reuters) - Bayer said it halted trials testing its experimental uterine fibroids treatment vilaprisan, which it previously expected to generate peak annual sales of more than 1 billion euros ($1.1 billion), citing the risk of side effects.

“For vilaprisan we have just some days ago put clinical development of our ongoing trials on hold,” said drug development head Joerg Moeller, speaking at the group’s capital markets day in London.

“That is due to very recent safety findings in long-term toxicology studies ... We have therefore decided as a precautionary measure to stop enrolment into our ongoing program and evaluate the data,” he added.

The toxicology data were from pre-clinical long-term testing of the drug on rodents, carried out in parallel with late stage testing on humans, a spokeswoman said.

Reporting by Ludwig Burger; editing by Thomas Seythal