Australia’s Metabolic Pharmaceuticals announced on Feb. 21st that diet drug AOD9604 had failed in a second Phase II clinical study and said it was “terminating” development of the drug.

The trial involving 536 subjects found that those taking the drug over a 24-week period had a weight loss of "less than one kilogram" more than those on a placebo – not statistically significant, particularly given that study participants were also on a diet and exercise program.

The oral peptide drug candidate was a fragment of the human growth hormone (hGH) protein designed to promote weight loss by increasing the metabolism of fat in obese individuals without decreasing glucose tolerance.

The first four weeks of the study consisted solely of a formal diet and exercise program, similar to one that would be prescribed in longer duration and larger phase 3 studies. Following that run-in period the participants were randomized to either the active drug or placebo.

The drug had previously been studied in a phase 2b study at doses ranging from 1mg to 30mg where the lowest dose was the most effective -- but still did not reach statistical significance.

The company commenced this latest phase 2b study in order to investigate doses below 1mg in the hope that the drug worked better at lower doses, and study participants were divided up into three active drug groups: 0.25mg, 0.5mg and 1mg.

Although there were no safety and tolerability issues, the drug failed to produce a statistically significant effect except in a small subgroup of female participants who had not responded well to diet and exercise alone.

Therefore, the company has terminated the development of a drug that had once seemed extremely promising in preclinical animal models of obesity.

-- By Rafi Allos