Theratechnologies Inc. and the FDA agreed on a special protocol assessment for a confirmatory Phase III study of TH9507 in HIV-associated lipodystrophy, with the trial expected to start in the first quarter.

Meanwhile, the Montreal-based firm expects to report results from its first pivotal study involving 412 patients around the end of the year. That trial was initiated in March 2005 without an SPA, following assurances from the FDA that there would be "no ambiguities" and "no valued added with an SPA," Yves Rosconi, president and CEO of Theratechnologies, said during a conference call.

However, changes to the HIV-associated lipodystrophy space, most notably the filing earlier this year of a supplemental new drug application by potential competitor Serono SA for its Serostim (recombinant human growth hormone) in that indication, prompted Theratechnologies to seek a binding agreement with the agency regarding trial protocol.

"We're getting ready to invest many more millions" in TH9507, Rosconi said, and the value of the SPA is that "it reduces risk."

The SPA confirms the primary endpoint of an 8 percent reduction in visceral adipose tissue (VAT) after 26 weeks of treatment - the same endpoint is being evaluated in the first study - and approves the company's statistical analysis approach for measuring change in VAT.

The second Phase III trial is expected to enroll about 400 patients with HIV-associated lipodystrophy, a metabolic syndrome characterized by changes in distribution of adipose tissue, dyslipidemia and glucose intolerance.

TH9507, an analogue of growth hormone-releasing factor, was tested in more than 600 patients in a Phase II program and demonstrated an ability to lower visceral fat reduction, increase muscle mass with trends for functional improvement, improve lipid profiles, stimulate the immune system and enhance daytime alertness.

Rosconi commented briefly on recent Phase III data reported by Geneva, Switzerland-based Serono, which showed that Serostim met its primary endpoint in patients with HIV-associated lipodystrophy, also referred to as HIV-associated adipose redistribution syndrome.

Despite the potential competition, Serono's data provided some encouragement for Theratechnologies' TH9507.

The two products "do have something in common," Rosconi said. "Both rely on the effects of human growth hormone to reduce VAT.

Theratechnologies began enrolling patients in the first study in late June 2005, and completed enrollment in March. Last month, the independent Data Safety Monitoring Board recommended continuation of the study following a review of 181 patients.

To date, 358 patients have completed at least 13 weeks of treatment, and 173 of those have finished the full 26 weeks.

Theratechnologies' stock (TSX:TH) gained C24 cents Wednesday to close at C$1.78 (US$1.60).