Arena fails to convince FDA panel on obesity drug

Arena Pharmaceuticals has failed to persuade an FDA panel to back lorcaserin as an effective treatment for obesity. In reaction to the decision, Adam Feuerstein, who blogged during the meeting, said the no votes seemed to take the day "because of unanswered concerns about the risk and middling efficacy." The vote seemed to mirror the vote on Vivus' Qnexa roughly two months ago, he adds.

The Endocrinologic and Metabolic Drugs Advisory Committee voted 5 to 9 against a question that asked whether the potential benefits of the product outweighed its potential risks "when used long-term in a population of overweight and obese individuals," the Wall Street Journal reports. "I voted no because there's too much uncertainty,'' said panel member Jessica Henderson, who was the consumer representative on the committee (as quoted by the New York Times).

As the NYT notes, lorcaserin mimics the effect of the brain chemical serotonin and has an effect on suppressing appetite. Its mechanism of action is similar to that of fenfluramine, which was part of the fen-phen diet pill combination removed from the market for damaging heart valves.

The vote doesn't seem surprising, given many analyst's predictions. Adam Cutler and Manisha Narasimhan of Canaccord Genuity, an investment banking and institutional brokerage firm with its U.S. operations headquartered in Boston, said in the note that they expected the lorcaserin committee review to be "rocky."

Arena, a small company with no approved products, said the drug was safe at recommended doses and would help fight obesity epidemic, Reuters notes. Japan's Eisai holds the U.S. marketing rights to the drug. The companies believe the drug has "a positive benefit-risk profile" and "will work closely with the FDA" on the review, Arena CEO Jack Lief says in a statement.

And other companies with obesity candidates have reacted to the panel's decision. "The panel's vote against approval for lorcaserin underscores the importance of safety, especially in the face of limited efficacy," Zafgen President and CEO Tom Hughes tells FierceBiotech in an emailed statement. He added that approval of "modestly effective drugs" is always challenging.

Zafgen's approach to obesity focuses on restoring control of key metabolic processes, which releases stored fat that is then used by the body as fuel. Hughes thinks the outcome "should have little impact on the direction of our program." Indeed, "Zafgen's program targets the treatment of severe obesity as a pharmacological alternative to bariatric surgery.  The medical proposition for our program differs significantly from that of lorcaserin.  We anticipate rapid and significant weight loss, significant improvements in metabolic risk factors, and a relatively short-term duration of treatment to bring patients down to a much healthier body weight," he adds.  

Meanwhile, Athersys' Chairman and CEO Gil Van Bokkelen, said he thinks Thursday's decision "was a reflection of some compound specific issues they see with Lorcaserin, and the approach Arena took in development.  Other than helping to clarify what their standards are, I don't think it has major ramifications for obesity drug development."

Athersys has an obesity program in preclinical development that focuses on the 5HT2c receptor--the same receptor that is the target for lorcaserin. The company is developing a drug that has shown significantly more selectivity to the 5HT2c receptor and therefore could be more efficacious based on preclinical comparative studies conducted to date.

"The decision should incentivize people to listen to the input from the FDA and design their pivotal studies very carefully.  We try to listen to the agency very carefully and incorporate what they tell us early on, which I've always believed is the right approach," Van Bokkelen concludes.  

- read more from the WSJ
- check out the NYT's report
- see the Reuters story
- get more from TheStreet

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