Targeting Hyperglycaemia with Anti-Obesity Drugs: Time for a Paradigm Shift?

Cardiovascular Safety and Superiority of Anti-Obesity Medications

Over the past few decades, several anti-obesity medications have demonstrated an association with adverse cardiovascular outcomes, leading to their market withdrawal. This has caused researchers to investigate the cardiovascular safety of such medications in cardiovascular outcome trials. However, the data from these trials are limited, and their outcomes are not promising. Therefore, the aim of this review is to provide an overview of the current and past Food and Drug Administration-approved medications for weight loss, including novel diabetes medications (glucagon-like peptide 1 receptor agonists and sodium-glucose co-transporter-2 inhibitors) and non-diabetes medications, and to highlight the current designs of cardiovascular outcome trials and their importance in the evaluation of the overall safety concerns associated with these anti-obesity medications. The limitations of the trials and opportunities for improvement were also evaluated. Finally, we also briefly describe cardiovascular safety and risks in this review.

Evolution of pharmacological obesity treatments: focus on adverse side-effect profiles

Pharmacotherapy directed toward reducing body weight may provide benefits for both curbing obesity and lowering the risk of obesity-associated comorbidities; however, many weight loss medications have been withdrawn from the market because of serious adverse effects. Examples include pulmonary hypertension (aminorex), cardiovascular toxicity, e.g. flenfluramine-induced valvopathy, stroke [phenylpropanolamine (PPA)], excess non-fatal cardiovascular events (sibutramine), and neuro-psychiatric issues (rimonabant; approved in Europe, but not in the USA). This negative experience has helped mould the current drug development and approval process for new anti-obesity drugs. Differences between the US Food and Drug Administration (FDA) and the European Medicines Agency, however, in perceptions of risk-benefit considerations for individual drugs have resulted in discrepancies in approval and/or withdrawal of weight-reducing medications. Thus, two drugs recently approved by the FDA, i.e. lorcaserin and phentermine + topiramate extended release, are not available in Europe. In contrast, naltrexone sustained release (SR)/bupropion SR received FDA approval, and liraglutide 3.0 mg was recently approved in both the USA and Europe. Regulatory strategies adopted by the FDA to manage the potential for uncommon but potentially serious post-marketing toxicity include: (i) risk evaluation and mitigation strategy programmes; (ii) stipulating post-marketing safety trials; (iii) considering responder rates and limiting cumulative exposure by discontinuation if weight loss is not attained within a reasonable timeframe; and (iv) requiring large cardiovascular outcome trials before or after approval. We chronicle the adverse effects of anti-obesity pharmacotherapy and consider how the history of high-profile toxicity issues has shaped the current regulatory landscape for new and future weight-reducing drugs.