Will New Weight-loss Drug Make it to Market?

Lorcaserin Reports Moderate Weight Loss in Late-Stage Obesity Trials

Sep 27, 2009 Christine Redmond

Lorcaserin is one of the most advanced weight-loss drugs in development for obesity, but may have only just met FDA criterion for effective weight loss.

Lorcaserin is one of the most advanced antiobesity drugs in clinical development; two others include Qnexa and Contrave. With late-stage trials having reported results for each of these drugs this year, many analysts are sceptical that lorcaserin will be approved by authorities, as major trial results indicate this drug may only just meet the FDA criterion for weight management.

Lorcaserin – a New 5HT Antagonist

Lorcaserin is a new appetite suppressant being developed for the treatment of obesity. It is a 5HT antagonist that is reportedly more specific than other products of this kind, such as fenfluramine, which was previously removed from the market due to increased risk of heart valve abnormalities. The new weight-loss drug should therefore have fewer side effects.

FDA Criterion to be Considered an Effective Weight-Loss Drug

According to the FDA criterion, a new drug is considered to be effective for weight management if after one year of treatment either of the following is achieved:

  • at least a 5% difference in weight loss between the treatment and control groups
  • the proportion of patients who lose greater than or equal to 5% of their initial body weight in the treatment group is at least 35% and is approximately double the proportion in the placebo group

Effectiveness of Lorcaserin for Inducing Weight Loss

The phase 3 program for lorcaserin consists of three studies, two of which have reported results recently. The BLOOM trial (Behavioural modification and Lorcaserin for Overweight and Obesity Management) and BLOSSOM trial (Behavioural modification and Lorcaserin Second Study for Obesity Management) each assessed 10mg lorcaserin twice-daily versus placebo in obese patients with or without co-morbid conditions and in overweight patients with at least one co-morbid condition. The BLOOM trial was a two year study, while the BLOSSOM trial was carried out for one year.

In BLOSSOM, lorcaserin-treated patients lost on average 7.9% of their initial body weight after one year of treatment; however, patients who received placebo lost an average of 3.9 % their initial body weight, reducing the placebo-corrected weight loss benefit for this drug. This is consistent with results for BLOOM after one year of treatment, which showed an average weight loss of 8.2% for the treatment group compared with 3.4% for the placebo group. In comparison, obesity treatments Qnexa and Contrave both achieved greater average placebo corrected weight loss, the greatest being a 12.5% corrected weight loss for patients treated with Qnexa in the EQUIP trial.

In addition, lorcaserin treatment resulted in only nearly double the proportion of treated patients losing 5% of their initial body weight compared with the control group, while both Qnexa and Contrave saw more than three times the treated patients achieve this outcome compared to control groups.

While lorcaserin boasts that the drug resulted in a large average weight reduction of 16.5% in a quarter of patients treated with the drug, Qnexa greatly supersedes this with weight loss of more than 15% achieved in 43% and 39% of treated patients in two separate trials.

Based on the low effectiveness for lorcaserin at inducing weight loss compared with Qnexa and Contrave, many analysts are skeptical of the success for this drug.

Side Effects for Lorcaserin

Importantly, lorcaserin treatment was not associated with any risk of heart valve abnormalities and was overall well tolerated. Side effects included upper respiratory infection, nasopharyngitis and headache. In addition, the weight-loss drug was not associated with any depression or suicidal thoughts, as has been with Acomplia, a drug that was removed from the European market in 2008 due to a high risk of psychiatric side effects.

Drug therapy for obesity treatment is limited. Therefore any new products that become available will be a welcome option for patients. Whether lorcaserin makes it to market will depend on the FDA review. Nonetheless, in line with analysts’ views, it seems that lorcaserin usage will trail its rivals, Qnexa and Contrave, which are both likely to be blockbuster drugs.

Readers may also be interested in the following article: New Hope on the Horizon for Obesity

Sources:US Department of Health and Human Services Food and Drug Administration, Center for Drug Evaluation and Research (CDER) 2007, 'Guidance for Industry Developing Products for Weight Management – Draft Guidance', February 2009, Accessed 18th September 2009

Arena Pharmaceuticals 2009, 'Arena Pharmaceuticals Reports Positive, Highly Significant BLOSSOM Trial Results for Weight Management; NDA Submission on Track for December', Septermber 18th 2009, Accessed 18th September, 2009

The copyright of the article Will New Weight-loss Drug Make it to Market? in Weight Loss is owned by Christine Redmond. Permission to republish Will New Weight-loss Drug Make it to Market? in print or online must be granted by the author in writing.
Obesity and Excess Body Fat, Jim Malmberg Obesity and Excess Body Fat
   
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