Report links Sanofi epilepsy drug with thousands of birth defects

French pharma company Sanofi

A study by French health authorities has found Sanofi’s epilepsy drug Depakine (valproate) and its generics are linked with severe birth defects in up to 4,100 children in France since it was first marketed there in 1967. 

Women who took the drug during pregnancy were four times more likely to have babies with malformations, according to the joint report by France's drug regulator ANSM and the national health insurance administration, CNAMTS.

A second study will explore risks of neurodevelopmental disorders, with results expected in the second half of 2017.

The reported estimated that between 2,150 and 4,100 babies had been affected, with defects attributed to the drug including spina bifida, as well as defects of the heart and genital organs.

Authors said that from 1967 to 2016, between 64,100 and 100,000 pregnancies in France were exposed to the drug, resulting in between 41,200 to 75,300 live births.

Most birth defects occurred for women treated for epilepsy, although from the late 1970s the drug was also prescribed for bipolar disorder.

Women taking the drug for bipolar disorder were twice as likely to give birth to children with serious birth defects, the study found.

Although the risk of birth defects associated with the drug has been known since the 1980s, valproate can still be prescribed to pregnant women when other forms of treatment fail – although that ruling was introduced two years ago.

The risk of birth defects with other epilepsy and bipolar disorder drugs was less marked, although risks varied with different medicines, according to the report.

Sanofi still markets valproate under the brand name Depakine in France, but generics are also available.

A group of French families of children with birth defects, whose mothers took valproate while pregnant, have sued Sanofi, claiming it did not adequately warn about the risks.

Sanofi said in a statement that it had been “transparent with health authorities”, noting that the results confirm data already known and published.

The company noted that ANSM 's figures are based on an extrapolation of the number of cases, which cannot be verified. The regulator itself said the figures should be "interpreted with caution", according to Sanofi's statement.