Denmark´s NeuroSearch is still seeking a partner to help develop and sell tesofensine, 15 months after releasing initial trial results. According to company researchers, the weight loss in study patients on tesofensine is about double that reported by Acomplia and Abbott Laboratories' Meridia (also sold as Reductil).

The amount of pounds shed also beat that achieved by other experimental drugs, including Vivus Inc.'s Qnexa and Orexigen Therapeutics Inc.'s Contrave and Empatic.

NeuroSearch says it needs the funding and reach of a Pfizer, Eli Lilly & Co, or Merck, all of whom the company said it has been in talks with, to complete the last of three patient trials needed to gain regulatory approval of tesofensine and to reach patients and primary care doctors.

The trials may enroll more than 7,000 participants and cost more than 100 million euros ($129 million dollars), NeuroSearch said in September, and the company cannot finance it alone.

Side effects associated with weight-loss drugs, however, have raised the concerns of regulators. Sanofi-Aventis announced it will halt all human trials of Acomplia after health authorities requested tests be stopped because of the risk of psychiatric disorders.

Pfizer Inc. followed by saying it will quit testing an obesity drug similar to Acomplia because getting U.S. approval would be too expensive and risky. Merck & Co. gave up on developing its obesity treatment last month.

However, Tesofensine works differently on the brain than Acomplia, so regulators' decision to shelve the Sanofi drug only eliminates competitors, said NeuroSearch CEO Flemming Pedersen. The drug causes three brain chemicals to stay at abnormally high levels, making patients feel full earlier and longer after eating. Normally, noradrenaline, dopamine and serotonin levels recede.

According to an article published in The Lancet in October on a NeuroSearch-sponsored trial, a dose of 0.5 milligrams taken daily for 24 weeks led to an average weight loss of 11.3 kilograms (24.9 pounds). An 11 percent increase in heart beats per minute was the most significant side effect.

Drugmakers are seeking to tap the obesity treatment market because of its expected growth. The number of obese people may climb by as much as 75 percent in 10 years, from 400 million in 2005 to 700 million in 2015, the World Health Organization estimates.