SAN DIEGO (AP) — Arena Pharmaceuticals Inc. said Monday its developing obesity treatment lorcaserin met weight reducing goals in a late-stage study, though the results still fell shy of proposed Food and Drug Administration guidelines. The Phase 3 clinical trial involved 3,182 patients receiving the drug in 10-miligram doses, twice-daily. The treatment was compared with placebo. In all, 47.5 percent of patients taking lorcaserin lost at least 5 percent of their body weight, compared with 20 percent on placebo, after 12 months. The average weight loss of 5.8 percent, or 12.7 pounds, topped placebo patients with 2.2 percent, or 4.7 pounds. Also, 22.6 percent of lorcaserin patients lost at 10 percent of their body weight, compared with 7.7 percent in the placebo group. But, the weight-loss difference between lorcaserin and placebo patients was only 3.6 percentage points, short of the FDA's draft standard of at least 5 percentage points. Meanwhile, the company said the drug was well-tolerated by patients, with the most frequent side effects being headaches and upper respiratory tract infections. The study, called Bloom, is one of three late-stage clinical trials on the drug candidate. Additional study results are expected throughout the year.