Small firm’s fen-phen-like obesity drug shows promise
Arena Pharmaceuticals Inc. has bet it can develop a drug from the same family as the notorious diet pill combination fen-phen -- and the gamble may be paying off.
Arena, with a market value of just $465 million, is convinced it can make its obesity drug work without causing the heart damage associated with fen-phen.
And on Monday, San Diego-based Arena said an interim safety review of a trial of the drug, lorcaserin hydrochloride, showed that it caused no heart safety problems after 12 months.
“This is huge,” said Dr. Bryan Roth, a psychiatrist at the University of North Carolina who specializes in drug actions and side effects. “This is the big thing everyone was waiting for, and my guess is it will encourage other companies with similar compounds at earlier stages of development to move them along quickly.”
Fen-phen combined Wyeth’s drugs Pondimin and Redux with the stimulant phentermine to create a popular cocktail that stands out as one of the most costly failures in drug history.
Pondimin and Redux, also known as fenfluramine and dexfenfluramine, were withdrawn more than a decade ago, but Wyeth, which has spent billions of dollars over the years to settle legal claims, has only recently been able to put the issue behind it.
Roth, who has no financial ties to Arena, is more familiar than most with the fen-phen story and was the first to try to figure out why fenfluramine caused heart valve damage.
“No one was interested in finding out why the drug was toxic,” he said. “People just wanted to run from it.”
After considerable research, Roth and other researchers developed the theory that the problem with fenfluramine was that it activated a cellular receptor known as 5-HT2b.
The 5-HT2b receptor is closely related to a receptor known as 5-HT2c, which is known to suppress appetite and is also activated by fenfluramine. Roth hypothesized that 5-HT2b was the culprit behind cardiovascular problems.
That theory gained some validity last year when U.S. health officials withdrew a drug called pergolide that was developed by Eli Lilly and & Co. Pergolide too activates the 5-HT2b receptor.
Arena’s drug selectively targets 5-HT2c. Although it may also hit 5-HT2b, so far it does not appear to cause problems.
Athersys Inc., which has a market capitalization of about $67 million, claims its similar drug is even more selective. That drug is at an earlier stage of development than Arena’s.
Shares of Cleveland-based Athersys rose 15 cents, or 4.2%, to $3.70, while shares of Arena climbed 23 cents, or 3%, to $6.54.
