Arena's Obesity Drug Safe for Trial

Arena Therapeutics(ARNA Quote) said Tuesday that an independent data safety monitoring board (DSMB) gave it the green light to continue its ongoing phase III trial on obesity drug lorcaserin.

The board found no substantial evidence of heart-valve damage six months into the Bloom study. The news brightens the program's risk profile, but investors still have to bet on safety data that will be assessed at 12, 18 and 24 months.

The DSMB review evaluated heart-valve damage, the culprit behind the 1997 recall of Wyeth's(WYE Quote) fen-phen (fenfluramine/phentermine) weight-loss drug. It's an important safety checkpoint for lorcaserin, which will have to continue to pass such evaluations further into the course of Arena's Bloom study.

The DSMB reviewed unblinded echocardiograms after patients had been dosed for six months in the study, looking for any differences in the rates of Food and Drug Administration-defined valvulopathy, or heart valve damage, in patients treated with lorcaserin vs. the control group. The results didn't meet predetermined stopping criteria.

In addition, Arena said the review confirmed that the rate of FDA-defined heart-valve damage in the placebo group was consistent with the company's statistical powering assumptions used to design the pivotal trial program. Consequently, increasing the trial enrollment isn't necessary. Also, analysts at Piper Jaffray said in a report Tuesday that they consider the absence of commentary on other psychiatric or neurological side effects as a positive.