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Pharmaceutical evaluation

Evaluating the benefits and risks of obesity drugs

The processes used to evaluate pharmaceutical interventions to treat obesity could be transformed, according to a new report.

Belviq (left) and Qsymia are the only two weight loss drugs currently approved by the FDA.

The “Obesity Drug Outcome Measures” report, published by The George Washington University School of Public Health and Health Services, outlines a series of new approaches that should be considered by the FDA when evaluating the benefits and risks of obesity drugs. The Obesity Drugs Outcome Measures Dialogue Group was composed of a panel of experts and diverse stakeholders who identified the key issues surrounding the evaluation of obesity drugs.

“At a time when so many Americans suffer with obesity and are faced with limited treatment options, there has been a rising call to review the emerging science on obesity to update the framework used when evaluating obesity drugs,” said Dr Christine Ferguson, Professor in the Department of Health Policy. “The FDA, under a re-authorised Prescription Drug User Fee Act, is likely to take a wider, more comprehensive look at how drugs developed to treat obesity affect how individuals with obesity feel and function. This report may help update the risk-benefit framework.”

The report, which explored why the development and approval of obesity drugs have proven so difficult, makes several recommendations including:

  • Obesity affects everyone differently - evaluating the benefits and risks of interventions should reflect the various considerations within the different categories of obesity based on feeling, functioning and health impairments.
  • Obesity drugs may provide an additional option for helping individuals who do not respond, or inadequately respond, to other interventions.
  • Potential pharmaceutical interventions should be reviewed as obesity treatments rather than weight loss agents and should be limited to only those for whom they are medically appropriate.
  • The benefit-risk evaluation of treatment with obesity drugs should extend beyond numerical weight loss to improvement in feeling and functioning.

In the last month, the FDA has approved two obesity drugs (Belviq and Qsymia), the first such approvals in more than a decade. However, this raises the question of why the development and approval of pharmacological interventions for treating obesity have proven so difficult.

According to the report, the approval new obesity drugs has been limited due to concerns over drug safety, medically inappropriate use and the overall benefits of obesity drugs – 5-10% weight loss demonstrated on average in clinical studies.

The FDA

According to the report, clinicians and patients have repeatedly called for additional treatment options to be used in conjunction with lifestyle interventions, including pharmacotherapy.

When considering new weight loss drugs, the FDA follows the draft 2007 Guidance for Industry on Developing Products for Weight Management and considers the recommendations of experts that sit on its Endrocrinologic and Metabolic Drugs Advisory Committee. Under the current Guidance for Weight Management Products, the FDA evaluates drugs intended for the clinical treatment of obesity based primarily on percentage of weight lost and changes in cardiometabolic factors such as blood pressure and lipid levels.

However, the Guidance for Industry on Developing Products for Weight Management does not explicitly include consideration of more symptomatic impairments in patient feeling and functioning, so companies do not tend to provide data on how a proposed obesity drug affects these types of health conditions. Subsequently, the FDA is unable to consider drug-specific improvements in these additional feeling and functioning domains when making approval decisions.

The report also states that the FDA is not just concerned with efficacy and tolerability of drugs; the overall impact on health status must be considered in judging the benefits of an obesity medication, not just the medication's impact on weight alone.

Therefore, under a re-authorised Prescription Drug User Fee Act, the FDA is likely to take a wider, more encompassing look at how drugs developed to treat obesity affect how individuals with obesity feel and function. Moreover, the agency will include patient-centred outcomes in its risk-benefit framework for evaluating these drugs.

Findings

The report also made several recommendations with regards to the approaches obesity as a disease and post market surveillance of pharmaceutical interventions:

  • Drugs under investigation for the clinical treatment of obesity should be reviewed as obesity treatments rather than weight loss agents.
  • Current clinical treatment options for obesity are limited, and obesity drugs may provide an additional intervention for helping individuals who do not respond, or inadequately respond, to other treatment interventions.
  • The benefit-risk evaluation of treatment with obesity drugs should extend beyond numerical weight loss to improvement in feeling and functioning. Drug development and review should more adequately capture and consider how obesity drugs affect how individuals feel and function on a daily basis.
  • Obesity is not a homogenous condition. The evaluation of the benefits and risks of pharmacologic intervention should reflect the different considerations within different categories based on feeling, functioning, and health impairments of obesity.
  • Use of obesity treatments should be limited to those for whom they are medically appropriate. Obesity drugs, like all drugs, come with side effects and risks. This requires responsible use and promotion and may require limiting access to obesity drugs to those individuals most likely to benefit due to their significant weight-related impairment in health, feeling, and functioning.

Conclusions

The authors concluded that the current FDA framework does not adequately categorise which types of patients with obesity could achieve benefits in feeling, function, and health risk. In addition, it stated that the agency does not adequately capture the many potential benefits of weight loss (short-term symptomatic, longer-term comorbidities or effects on quality of life) that may be improved through modest weight loss, aided by pharmacologic treatment.

As a result, the report claims a more comprehensive patient-centred approach in making risk-benefit determinations could help the FDA ensure that safe and effective obesity drugs are available to both adult and paediatric patient groups for whom the benefits of improved physical and mental health and quality of life outweigh the risks associated with a particular drug.

The report was supported by unrestricted gifts from Eisai, Novo Nordisk Worldwide, Obesity Action Coalition, Orexigen Therapeutics, Takeda Pharmaceuticals, the FDA and Vivus.