Arena’s Weight-Loss Pill Lorqess (lorcaserin): Waiting For FDA

Tomorrow is the deadline for the Food and Drug Administration to make a decision about whether or not to approve Arena Pharmaceuticals’ experimental obesity drug Lorqess (lorcaserin). In advance of the decision I’ve recapped some Lorqess news and information from the last several months. We will update you when FDA’s decision comes in.

Of the three potential new diet pills racing to reach the market, Lorqess (lorcaserin) is the only one where the active ingredient is a completely new molecule. Its competition, Vivus’s Qnexa and Orexigen’s Contrave, are both combinations of drug molecules that have already been FDA-approved for other conditions.

Lorqess targets an appetite-suppressing serotonin receptor located in the brain. It’s the same receptor that was targeted by fenfluramine, an ingredient in the infamous Fen-Phen obesity drug combo. Fenfluramine was associated with heart valve damage and a fatal lung disorder- it was pulled from the market in 1997.

Lorcaserin is different from fenfluramine- it is more selective for the specific subtype of serotonin receptor found in the brain and avoids the one that’s found in the heart. Arena’s idea behind Lorqess was that a more selective drug might have the weight-loss benefits with fewer side effects. Arena has had to pay special attention to safety throughout lorcaserin’s development and they haven’t run into heart valve trouble.

In July, Arena landed a partner for marketing Lorqess- Japan’s Eisai.

But last month, when an FDA panel met to discuss Lorqess, the outcome was disappointing for Eisai and Arena. Background materials for the panel session raised questions about malignant tumors that occurred in rats given high doses of lorcaserin. And the panel itself recommended that FDA not approve Lorqess by a 9 to 5 vote. The panel decided not enough data was available to assuage concerns about safety, and was also concerned about how the drug would work in a wider population than was tested during clinical trials. In the aftermath of the panel recommendation, analysts suggested a number of pieces of data that Arena could provide to improve its overall package of information about Lorqess, and thus the drug’s chances. But many of the suggestions, which included a detailed study of the mechanism behind the rat tumors, and a Phase II proof of concept trial of lorcaserin and phentermine in diabetics, take years, not months.

Today’s FDA decision is sure to set the tone for the next couple of months, since Lorqess is the first of the three big contenders to be judged. FDA could decide to ask for more data on Lorqess, or make a decision outright. Stay tuned.

Author: Carmen Drahl

Share This Post On