Belgium’s Solvay has become the latest firm to end development of a cannabinoid obesity compound.

The Brussels-headquartered firm said that it will discontinue all R&D activities for its investigational compound SLV319. The drug, a selective cannabinoid type 1 antagonist, was in Phase II development for the treatment of obesity and recent data confirmed its clinical activity and efficacy.

However, Solvay had noted last month that it was analysing the next step for the development of the molecule after partner Bristol-Myers Squibb returned the worldwide rights to the compound. Claus Steinborn, head of global pharma R&D at Solvay, noted that “while the discontinuation is not related to any adverse events or the efficacy of the compound, we have made this decision after careful evaluation of the current regulatory environment, leading to new and high regulatory hurdles for approval of a compound of this class”.

This is the same reason given by Pfizer earlier this month when it ended a Phase III development programme on its cannabinoid receptor antagonist known as CP-945,598. The firm said the drug has the potential to be a safe and effective treatment for weight management but pulled the plug “based on changing regulatory perspectives on the risk/benefit profile” of the drug class”, which has been associated with serious psychiatric disorders.

The most high-profile drug in the latter class was Acomplia (rimonabant) from Sanofi-Aventis. At the beginning of November, the French drugmaker terminated all its clinical studies on the controversial anti-obesity drug, a couple of weeks after European regulators concluded that the benefits of Acomplia “no longer outweigh its risks” and suspended marketing authorisation.