By Kamal Choudhury
(Reuters) -Moderna said on Wednesday it would stop developing its experimental vaccine to prevent cytomegalovirus, a virus that can cause birth defects, after it failed to meet the main goal of a late-stage trial.
Shares of the drugmaker were down over 5% in extended trading following the news.
The late-stage trial tested the vaccine, mRNA-1647, in about 7,500 women aged 16 to 40. The shot showed efficacy ranging between 6% and 23%, depending on how the cases were defined, which was below Moderna’s target.
Cytomegalovirus is a common virus that usually causes mild illness. However, if passed from mother to baby during pregnancy, it can lead to congenital CMV, a condition that may cause birth defects or long-term health problems.
There is currently no approved vaccine to prevent congenital CMV.
Nearly one in three U.S. children is infected with cytomegalovirus by age five and about one in 200 babies is born with the congenital form, according to the CDC.
“We are clearly disappointed by the failure to prevent primary infection because it means there is still no vaccine for the prevention of congenital CMV despite the many decades of work by the field,” said Moderna President Stephen Hoge, MD.
“Like most investors, we saw CMV failure a matter of when, not if,” said analysts at Leerink Partners, citing slow trial progress, a failed interim analysis and the management’s earlier signals about changing the study’s evaluation criteria.
TD Cowen analyst Tyler Van Buren said they had hoped Moderna’s vaccine would outperform Sanofi’s earlier CMV candidate, which showed around 50% efficacy before being discontinued.
Moderna said it will continue to evaluate the vaccine in a separate mid-stage trial in bone marrow transplant patients, where CMV reactivation can cause severe disease.
The vaccine was generally well-tolerated and no safety concerns were flagged, it said.
The company does not expect the trial failure to affect its financial outlook for 2025 or its goal to break even by 2028.
(Reporting by Kamal Choudhury in Bengaluru; Editing by Shreya Biswas and Maju Samuel)
