Three Indian pharmaceutical companies that have launched versions of diet drug rimonabant in India are reported unperturbed by the prospect that Sanofi-Aventis, original developer of rimonabant, may soon be selling the original version called Acomplia in the Indian market.

Torrent Pharma, Zydus Cadila and Sun Pharma, have all launched versions of rimonabant -- with Torrent's drug marketed as Rimoslim, Zydus Cadila's marketed as Slimona, and Sun's marketed as Riocity and Riobec.

While Sanofi-Aventis is expected to shortly receive Indian patent protection for Acomplia, the Mumbai (Bombay) newspaper Financial Express reports that a patent holder cannot block generics already available in the market -- but that Sanofi-Aventis can ask for a royalty from the generic companies.

However, Indian pharmaceutical companies are of the view that rimonabant is a molecule registered in 1994, and India is not obliged under World Trade Organization rules to respect patents and pay royalties on molecules developed prior to 1995.

“Rimonabant was discovered by Sanofi before 1995, thus Sanofi is not entitled to obtain product patent as per the patents laws of India," said Ruchir Modi, VP, marketing, for Torrent. "Hence, the question of paying royalty to Sanofi does not arise.”