In a previous month-long phase II study, APD356 demonstrated a highly statistically significant average weight loss of 2.9 pounds in patients taking a 15mg dose of the drug. This was compared to a loss of 0.7 pounds for a control group given placebo. Initial studies have shown the drug to be generally well tolerated at all doses investigated.
The current phase II trial is a randomized, dose-ranging study being conducted in the US. Approximately 400 obese patients have been divided into four groups to evaluate the safety and efficacy of orally administered doses of APD356 given at 10mg once daily, 15mg once daily, and 10mg twice daily, compared to placebo. The experiment is scheduled to last 12 weeks.
The dose of 10mg twice daily is expected to provide similar peak blood levels as the 15mg once daily dose, but higher blood trough levels, thereby maintaining higher average drug concentrations in the blood. The second dose will also provide a second peak in drug level to cover the evening hours.
In addition to standard safety evaluations, patients will be assessed by echocardiogram prior to enrollment and at the end of the treatment period. Patients will not receive any diet or exercise advice, but will be required to abstain from consuming alcohol. With the exception of the length of the trial, the design of this trial is substantially similar to the design of the four-week phase II study.