Marijuana Munchies help produce New Diet Pill

A marijuana joint might seem an odd starting point in the search for weight-loss secrets.

Yet a compound switching off the same brain circuits that make people hungry when they smoke cannabis looks set to become the world’s first blockbuster anti-obesity medicine, with sales tipped by analysts to top $3 billion a year.

Sanofi-Aventis SA’s Acomplia, or rimonabant, which could be approved by US regulators as early as next month, is the first of a new wave of treatments that may spell fat profits for some pharmaceutical companies.

Another two experimental drugs from Arena Pharmaceuticals and Alizyme, with different mechanisms of action, have also produced promising clinical results in recent weeks, prompting some investors to start laying big bets on weight-loss medicine.

It is a risky area, however. Slimming pills have had a chequered history, due to modest effectiveness and adverse side effects — most notoriously with the diet drug combination “fen-phen,” which was linked to heart-valve problems and has cost Wyeth more than $21 billion in provisions related to patient claims.

But past upsets have not deterred drug manufacturers from investing heavily in a new generation of possible winners. Jonathan de Pass, chief executive of specialist consultancy Evaluate, calculates there are now 26 new drugs in clinical trials for obesity and a further 32 in early-stage development. In addition, at least half a dozen diabetes medicines are being tried out as treatments for reducing weight.

The potential market is large in every respect. World Health Organisation (WHO) estimates more than 1 billion people globally are overweight and it could reach 1.5 billion by 2015. Of the current total, more than 300 million already rank as obese, putting them at substantial risk of heart disease, stroke, type 2 diabetes, respiratory problems and some cancers. Worryingly, the problem is also starting to spread rapidly in Africa. The western Pacific islands of Nauru and Tonga hold the dubious distinction of having the highest percentage rates of obesity in the world.

Given the scale of the problem, the arrival of new weight-loss drugs will be greeted with some excitement — but they may also pose a dilemma. Dr Timothy Armstrong of the WHO’s department of chronic diseases believes medication can help only a very small minority of patients and will not impact the overall obesity epidemic. “It’s not a panacea,” he said.