because of side effects, compared with 4.3 percent of those on placebo. The most common adverse events were low blood sugar (hypoglycemia), headache, upper respiratory infections, and back pain. None of the reports of hypoglycemia were considered severe, Arena said.
One last thing in today’s statement has to make Arena followers pause, though. The Arena drug, which is designed to block a receptor in the brain that controls feelings of fullness, has always been closely monitored for safety because of the similarity of this target to a related receptor found on heart valves. Scientists say that the old fen-phen combination from the ’90s was sunk because it failed to distinguish specifically enough between these two receptors, which created a multi-billion legal liability when patients on the drug reported cases of damaged heart valves.
Arena, based on pooled data from 7,000 patients in its previous studies, showed a 2.3 percent rate of patients with heart valve damage (known as valvulopathy) on its drug, compared with 2.2 percent for those on placebo. The Bloom-DM study showed at the 24-week analysis point that 2.5 percent of lorcaserin patients had new cases of valvulopathy, while 1.9 percent on placebo had the condition. At the full-year follow-up point 2.9 percent of lorcaserin patients had new cases of valvulopathy, compared with 0.5 percent on placebo.
Lief dismissed the significance of this finding, saying the Bloom-DM study was so small that it wasn’t designed to detect any differences in valvulopathy that might be statistically significant. Since the overall number of patients in the study was small, one case of valvulopathy equals 0.5 percentage points, meaning that one or two cases can create the appearance of a difference that may not actually be real.
Even so, the FDA has shown that safety is paramount with any new drug that has potential to be taken by millions of people. History has shown that unpredictable things can start happening then, and when they do, the FDA gets raked over the coals by indignant Congressmen in televised hearings. The safer thing to do, for regulators, is to keep asking for more trials, more proof. It will be fascinating to see if Arena and its partner have the money, the guile, and the willpower to beat the odds and win the blessing of a very cautious FDA.
Arena plans to discuss the results and take questions from investors on a conference call at 8:30 am Eastern/5:30 am Pacific time today.
