June 28 (Bloomberg) -- Eisai Co. surged the most in two years in Tokyo trading after its partner won Food and Drug Administration approval for a weight-loss pill, making it the first obesity medication cleared for the U.S. in 13 years.
The Japanese drugmaker jumped 4 percent to 3,505 yen as of 9:20 a.m. Tokyo time, the biggest intraday advance since May 2009, after San Diego-based partner Arena Pharmaceuticals Inc. gained backing to market the treatment. Dubbed Belviq, the drug affects an area of the brain that helps a person feel sated with less food, the FDA said yesterday in a statement. Arena has licensed the medicine to Tokyo-based Eisai to sell in the U.S.
More than 78 million U.S. adults are obese, according to the Centers for Disease Control and Prevention in Atlanta. Arena’s medicine, which will be its first marketed product, may reach sales of about $2 billion in 2020, said Edward Tenthoff, an analyst at Piper Jaffray & Co. in New York.
“Two-thirds of the people in this country are overweight or obese,” Tenthoff said in a telephone interview. “It’s an enormous opportunity.”
Arena increased 29 percent to $11.39 at 4 p.m. New York time yesterday.
Obesity raises the risks of diabetes, heart attacks and stroke, and costs the U.S. economy an estimated $147 billion a year in medical expenses and lost productivity, according to the CDC.
The pill works in a similar way to fenfluramine, part of the fen-phen appetite-suppression drug combination pulled from pharmacies 15 years ago when it was linked to heart valve abnormalities.
Arena and Eisai agreed to conduct six post-market studies to analyze the safety and efficacy of Belviq, including a long-term cardiovascular outcomes trial to assess the drug’s risk for major cardiac risks such as heart attack and stroke, the FDA said.
Belviq is indicated for people who have at least one coexisting condition such as high blood pressure or Type 2 diabetes. The drug will be available after the Drug Enforcement Administration completes a review to classify Belviq based on its potential for abuse, Arena said yesterday in a statement.
The drug agency’s decision may take four to six months, Arena’s management said yesterday on a conference call. The FDA recommended Belviq be classified among the fourth class of drugs of a five-tiered system, the company said, with those in the first class being the most restricted because they have the highest potential for abuse.
Those in fourth tier don’t have restrictions on samples, advertising or automatic refills. The primary requirement is keeping better records, Arena’s executives said.
The FDA said Arena’s pill shouldn’t be used by pregnant women. Belviq may cause serious side effects, including a fatal increase in the chemical serotonin produced by the body that can cause muscle rigidity, fever and seizures, especially when used with drugs that treat migraines and depression, the agency said. Belviq may also cause memory or attention disturbances, the FDA said.
The medication’s label also instructs patients to discontinue use if 5 percent of weight loss is not achieved by the 12th week of treatment.
Arena expects to begin the required cardiovascular study in mid-2013, management said. The company is responsible for 10 percent of the cost of the study and Eisai will assume remaining expenses.
Roche Holding AG’s Xenical was the last obesity medicine approved in 1999.
Arena’s drug, previously known by its chemical name as lorcaserin, was rejected by the FDA in 2010 because the agency had concerns about cancer. Advisers to the agency determined the benefits of the drug outweighed the risks.
The watchdog group Public Citizen, based in Washington, urged FDA Commissioner Margaret Hamburg to reject Arena’s medicine because of potential risks associated with heart valve abnormalities.
“Faced with this serious concern, it would be dangerous and unconscionable for you to allow the FDA to disregard the available evidence and subject large numbers of obese patients, already at risk of cardiovascular disease, to the added risk of damaged heart valves,” Sidney Wolfe, director of Public Citizen’s Health Research Group, wrote Hamburg yesterday.
Belviq’s label warns patients to consider stopping the drug if they exhibit signs of valvular heart disease and to get evaluated for valve abnormalities.
Patients who tested Arena’s treatment in three studies lost about 3 percent more of their body weight than those who took a placebo, FDA staff said in a May 8 report.
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