Obesity drugs may have a slim chance

From fit to fat — that would soon describe the globe. According to the World Health Organisation (WHO), the number of obese adults worldwide would grow from 400 million now to 700 million by 2015.

Given this, you'd think the market potential for obesity drugs would be huge. But that doesn't seem to be the case. Low efficacy and heavy adverse effects are making these drugs unpopular among consumers and healthcare experts alike.

Yogesh Aggarwal, senior consultant (bariatric surgery) at Fortis Hospital, Noida, said prescription of obesity drugs has dropped significantly, as much as over 70%, in the last few months. In India, where 16% of adult population falls in the obese category, there are two main drugs — orlistat and sibutramine — in the market. The effectiveness of both, however, is best described as 'moderate'. A third drug, rimonabant, is under heavy scrutiny as it causes side effects such as depression and suicidal tendencies. Due to these, the Drugs Controller General of India (DCGI) is planning to ban it.

While orlistat is manufactured by players such as Ranbaxy, Torrent Pharma and Intas Pharma, sibutramine is made by Sun Pharma, Torrent, and Intas, among others.

Ambrish Mithal, endocrinologist, Apollo Hospital, said, "Patients don't lose more than 5-10% of body weight (if they take these drugs). Also, these medicines work in only 70-80% of patients. In all obesity drugs, the weight loss continues for about six months, and then becomes very, very slow." Once the drugs are discontinued, weight gain is almost always certain.

Mithal said greater emphasis is now on changes in diet and lifestyle for weight loss. Anoop Misra, head of department (metabolic diseases), Fortis Hospital, said obesity drugs are given only to people who are severely overweight, that is, those with body mass index (BMI) of above 25. "Only top-rung doctors use obesity drugs. Several physicians don't know how to administer them," said Misra.

As for side effects, orlistat causes abdominal discomfort while sibutramine is associated with insomnia and even a rise in blood pressure.

These haven't stopped pharma firms like Piramal Healthcare, Glenmark Pharma, and Cadila Healthcare from exploring the potential. The drugmakers have novel molecules for obesity in the pipeline.
But will the side effects and low effectiveness make the going tough for them? Neelima Joshi, vice president (biological research), Glenmark Pharma, said, "There is, nevertheless, a huge potential for research to bring out new drugs, as obesity is a disease with unmet needs. So new pathways for treatment have to be devised."

Muralidharan Nair, partner (health sciences practice), Ernst & Young, felt any new obesity drugs should be able to address the influence of genetic factors on weight. "New drugs should address the cause and not just the symptoms," he said.