French drugmaker Ipsen has suffered a slight setback after it announced that it is halting a late-stage trial of a sustained-release version of its hormone therapy triptorelin.

The company said that it has stopped its investigational four-month formulation of triptorelin because the preliminary data do not support the expected sustainable blood levels of the drug for that period in all patients. As a result, Ipsen said it has decided not to perform the second administration of the drug as planned in the protocol, but noted that no safety concerns have been observed throughout the trial and at the end of their monitoring period, patients will be switched to appropriate approved treatment.

The firm added that the product, which is just one of its new sustained-release formulation candidates of triptorelin “using one amongst several Ipsen proprietary technologies”, had showed adequate efficacy and safety profile in Phase II studies. However, chief scientific officer Jacques-Pierre Moreau said that Ipsen is “taking all appropriate actions to solve the scale-up issues seen during Phase III which are inherent to advanced formulations based on cutting edge technologies”.

Triptorelin is a luteinising hormone-releasing hormone agonist and Ipsen currently markets the drug as Decapeptyl, a one and three-month sustained-release formulation for the treatment of advanced metastatic hormone-dependent prostate cancer. It is marketed in more than 80 countries and first-quarter sales reached 61.1 million euros. The challenge for the company now is to have a new formulation of triptorelin available when the current patents of the three-month formulation of Decapeptyl expire in mid-2010.

Ipsen remains confident that it will have a new formulation on the market by then and Dr Moreau said that "from the onset, the introduction of an innovative subcutaneous presentation using a new retro-injection device was well received by patients and investigators. Thus, the teams are now focusing their energy and expertise in order to resume Phase III as soon as possible.” He added that the firm’s drug delivery platform has already been validated through the success of Somatuline (lanreotide) Autogel for acromegaly and neuroendocrine tumours “and we are confident in Ipsen's ability to have a differentiated formulation of triptorelin".