Arena Pharmaceuticals, Inc. has announced the dosing of the first patient in the first of three-planned phase 3 clinical trials evaluating the efficacy and safety of its lead drug candidate, lorcaserin hydrochloride, for the treatment of obesity. Known as BLOOM (Behavioral modification and Lorcaserin for Overweight and Obesity Management), this double blind, randomized, and placebo-controlled trial will include about 100 centres in the US and is expected to enrol approximately 3,000 overweight and obese patients. The proportion of patients with a 5 per cent or greater weight reduction from baseline at week 52 is the primary endpoint.

"Based on the previously announced phase 2b data demonstrating that treatment with lorcaserin resulted in statistically significant, progressive and dose-dependent weight loss with a generally favourable tolerability profile, we believe lorcaserin has the potential to be an attractive new therapy for obesity," commented William Shanahan, MD, Arena's vice president and chief medical officer. "As we start the phase 3 programme, we are looking forward to the DSMB's review of the six-month echocardiographic data sometime around next summer as a significant safety milestone that will trigger the initiation of additional phase 3 studies."

The BLOOM trial will evaluate a 20 mg dose (10 mg dosed twice daily) of lorcaserin versus placebo over a two-year treatment period in obese patients (BMI 30 to 45) with or without co-morbid conditions and overweight patients (BMI 27 to 30) with at least one co-morbid condition. All patients will receive echocardiograms at baseline and follow-up echocardiograms at 6, 12, 18 and 24 months after starting the trial. An independent Data Safety Monitoring Board (DSMB) will review echocardiograms at 6 and 12 months. The DSMB will review echocardiographic data, and will make a judgment as to whether or not it is appropriate to precede with the trial at the time of each review.

The complete lorcaserin phase 3 programme is designed to enrol a total of approximately 6,000 patients in three pivotal trials. Assuming a positive six-month safety assessment from the DSMB for the BLOOM trial, two additional phase 3 trials enrolling a total of approximately 3,000 patients will be initiated. In these additional pivotal trials Arena plans to evaluate the 20 mg and 10 mg daily doses versus placebo over a one-year treatment period, with one of the trials evaluating patients with type 2 diabetes. Diet and exercise will be part of each of the pivotal trials in accordance with the FDA guideline. In addition to the above planned pivotal trial program, several other small studies, such as drug interaction and abuse potential studies will be conducted.

"The initiation of Arena's first phase 3 clinical programme is a major achievement for the company," commented Jack Lief, Arena's president and CEO. "Working with our committed group of clinical investigators, we are hopeful that we will be able to provide a new and important therapeutic option for overweight and obese patients, who currently have limited treatment options."