LONDON - Alizyme plc announced positive results in a Phase IIa trial of ATL-1251 in the treatment of irritable bowel syndrome, and said it has received approval to start a Phase Ib trial of its anti-obesity drug, ATL-962.

In the Phase IIa trial involving 20 patients with constipation-predominant irritable bowel syndrome, ATL-1251 showed improvement in a number of symptoms, including abdominal pain and discomfort. In addition, colonic motility and gastrointestinal transit time, determined radiographically, improved in more than 70 percent of patients, in a dose-dependent fashion.

The single-blind, placebo-controlled trial was carried out at two centers in the UK and two in Belgium. Patients received placebo for four weeks, followed by four weeks on a daily dose of ATL-1251, and four weeks on a twice-daily dose.

CEO Richard Palmer said, "We are very pleased to have obtained proof of concept for ATL-1251 in constipation-predominant IBS patients. The results of this pilot study are in line with expectations and are consistent with the data from the Phase I program."

Alizyme, based in Cambridge, England, licensed in ATL-1251 from SmithKline Beecham, of London. SB originally had the option to take the compound back after Phase II, but was forced to hand over the full rights to Alizyme in July in order to satisfy U.S. Federal Trade Commission concerns over its merger with Glaxo Wellcome.

ATL-1251 is a 5-HT4 receptor agonist/5-HT3 receptor antagonist. These 5-HT receptors influence gastrointestinal motility. Alizyme is now planning a Phase IIb trial and will find a partner for the compound once it has proof of efficacy.

The Phase Ib trial of ATL-962, a lipase inhibitor that prevents the breakdown of fat in the gut, will take place in a specialist center in Germany. It will involve up to 27 healthy non-obese volunteers, and is designed to determine safety of repeat dosing and proof of concept. Results are expected in the first quarter of 2001.

Palmer said ATL-962 has the potential to be the second lipase inhibitor on the market, following Roche's Xenical, which is estimated to reach US$1.6 billion in sales by 2005.