French pharma giant Sanofi-Aventis has been denied a request to block sales of a generic version of its Lovenox blood thinner by a US district court.

The US District for Columbia refused to issue a preliminary injunction to block the generic, marketed by Novartis AG’s Sandoz unit and Momenta, on the grounds that it would deny the public an important treatment.

Sanofi-Aventis has expressed concerns that the US Food and Drug Administration has failed to follow procedures and failed to ensure that the generic, which was approved in July, has the same active ingredient as Lovenox.