Last Updated 29 December 2014
In the simplest of terms, obesity is the result of an imbalance in energy intake versus expenditure, leading to excess energy stores in the form of body fat (adipose tissue). The complex underlying signaling mechanisms that influence food intake and energy expenditure work in unity to maintain adiposity, even if body weight is pathogenically high. The evidence demonstrating the serious physical, economic, and societal effects of obesity is growing, and it has resulted in more concerted efforts to confront this important public health issue. Lifestyle modifications, such as diet and exercise, are the cornerstone of obesity management, but have limited efficacy. Bariatric surgery is by far the most effective treatment for obesity, but historically it has been restricted to severely obese patients. Pharmacotherapy aims to provide additional weight loss for those patients for whom diet and exercise is insufficient and where surgery is not suitable or affordable. However, the body’s innate predisposition to retain adipose tissue makes weight loss through pharmacological intervention very challenging. Moreover, several high profile withdrawals of marketed antiobesity agents have occurred owing to serious adverse events. Understandably, physicians remain cautious about novel weight loss therapies. Entrenched attitudes about obesity being a lifestyle disorder, limited therapeutic options, and a challenging reimbursement environment in most markets have contributed to low diagnosis and drug-treatment rates. At first glance, the commercial opportunity of the obesity market looks considerable: a large number of prevalent cases with limited treatment options. However, it is the potential magnitude of the market that is one of its chief constraints. Healthcare budgets are unlikely to be able to finance wide reimbursement of obesity drugs, because of the number of eligible recipients. On the other hand, the long-term burden of the comorbidities and complications of untreated obesity will place an increasing drain on healthcare resources. Moreover, if access to obesity drugs is too difficult, there will be little incentive for pharmaceutical companies to invest in research and development in this field, which will only compound the problem. Nevertheless, we do expect the market to expand, driven in part by greater recognition of the medical, social, and economic implications of obesity, and greater willingness of political and professional organizations to take action. With three emerging therapies anticipated to launch in 2015, including the first agents to be approved in Europe and Japan for many years, physicians will have more treatment options and greater awareness of the problem leading to increases in diagnosis and treatment rates. The unmet need for pharmacological treatment options for obesity will lead to steady uptake of new therapies upon their launch, but only after early caution about the safety of these agents passes. We anticipate that a significant percentage of obese patients will find the degree of weight loss achieved with several emerging therapies falls short of their expectations, leading to high patient turnover. The wider use of medications in the large U.S. market will be the main driver behind overall growth in the obesity market.