Arena's New Obesity Drug Meets Trial Goals But Disappoints Wall Street

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Main Category: Obesity / Weight Loss / Fitness
Also Included In: Clinical Trials / Drug Trials
Article Date: 30 Mar 2009 - 10:00 PDT

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Arena Pharmaceutical shares fell over 20 per cent on Monday after the company announced its experimental obesity drug met endpoints of a a two year trial on over 3,000 patients on over 100 sites in the US, but fell short of the benchmark sought by the US Food and Drug Administration (FDA).

However, according to analysts who spoke to the Wall Street Journal, the trial results for Lorcaserin, the name of Arena's new obesity drug, should be enough to get the company the FDA approval it seeks.

Arena said in its own press release earlier to day that the top line results from the BLOOM (Behavioral modification and Lorcaserin for Overweight and Obesity Management) trial were "positive". The trial, where the new drug was tested against placebo, achieved statistically significant results (p<0.0001) on all three primary endpoints and treatment was well tolerated.

The three primary endpoints, in order of importance were:

1. The proportion of patients who lost 5 per cent or more of their weight in the first 12 months
   The trial showed that 47.5 per cent of lorcaserin patients lost 5 per cent or more of their body weight, compared to 20.3 per cent in the placebo group. .


2. The difference in mean weight loss compared to placebo after the first 12 months
   The average weight loss in the lorcaserin group in the first 12 months was 5.8 per cent of body weight (12.7 pounds), compared to 2.2 per cent (4.7 pounds) in the placebo group.


3. The proportion of patients who lost 10 per cent of more their weight in the first 12 months
   The trial showed that 22.6 per cent of lorcaserin patients lost 10 per cent or more of their body weight compared to 7.7 per cent in the placebo group.

According to the Wall Street Journal, it seems that analysts are disappointed with the middle result: the difference between the two groups is only 3.6 per cent, which is short of the 5 per cent the FDA is looking for.

However, there are also reports that the results are more than good enough to meet the FDA requirement for approval, and the Arena position is that the drug has met all its primary endpoints, shows statistically significant weight loss compared to placebo, and was well tolerated. The main statistic to focus is the first one: the percentage of patients who lost 5 per cent or more of their body weight, and this in fact exceeded the FDA benchmark of 35 per cent, they said.

Dr Steven R. Smith, Co-Principal Investigator and Professor and Assistant Director for Clinical Research at the Pennington Biomedical Research Center said in the Arena press statement that:

"The BLOOM results, demonstrating lorcaserin's medically important weight loss coupled with the tolerability and safety profile displayed in this trial, differentiate lorcaserin from approved drugs or other agents in clinical trials."

"Obesity is a widespread disease; having a well tolerated and effective therapy that can be used by the majority of patients who need weight reduction could also have beneficial effects on co-morbid conditions, such as diabetes, lipid disorders, and cardiovascular disease," he added.

Perhaps just as important is the safety profile of the drug, which shows that over the two year study period there were no patients with heart valve damage, a problem that caused Wyeth to recall its obesity drug in 1997, said Reuters report.

Dr Neil J. Weissman, Co-Principal Investigator, Director, Cardiac Ultrasound and Ultrasound Core Labs, President, MedStar Research Institute, and Professor of Medicine, Georgetown University, said in the Arena statement that:

"The echocardiographic safety data is very reassuring."

"In this double-blind, prospective study, there was no evidence of a difference in the development of valve disease in the large number of patients on lorcaserin versus control for up to two years of continuous use," said Weissman, adding that:

"No prospective valvulopathy trial has ever studied this many patients for this period of time, particularly under such well-controlled circumstances."

Arena said that compared to placebo, treatment with Lorcaserin was also linked to statistically significant improvements in a range of secondary endpoints, including: total cholesterol, LDL (so called "bad" cholesterol), triglycerides, and blood pressure.

Lorcaserin is the first in a new class of selective serotonin 2C receptor agonists.

The serotonin 2C receptor is in the hypothalamus and other parts of the brain and helps to control of appetite and metabolism.

According to 2007 figures from the US Department of Health and Human Services, a third of US adults are obese and two thirds are overweight. And according to a 2005 report from the International Diabetes Federation, the healthcare costs of obesity exceed 120 billion dollars a year.

Research shows that if obese people lose 5 to 10 per cent of their body weight they achieve significant reductions in a range of health risks, such as cardiovascular disease and type 2 diabetes.

Sources: Wall Street Journal, Reuters, Arena.

Written by: Catharine Paddock, PhD
Copyright: Medical News Today
Not to be reproduced without permission of Medical News Today

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