Inflated Claims and Inadequate Testing for Rexulti

FDA has a bone to pick with Otsuka, the company that sells Rexulti (brexpiprazole). The agency is taking issue with false advertising by the company for this drug used in schizophrenia and severe depression. To us, this problem of inflated efficacy claims is especially noteworthy because, for people with obesity who may need this drug, the clinical testing and dosing instructions are inadequate to ensure that the drug will work well.

When people need this drug, they really need it to work.

Notification of False of Misleading Advertising

In late October, FDA wrote to Otsuka to say that the company’s advertising claims about the effectiveness of Rexulti are false. The agency focused on claims in TV advertising, writing:

“Specifically, these claims misleadingly suggest that a patient can expect to experience a 62% reduction (i.e., an improvement) in depression symptoms when added to an antidepressant (ADT) alone. However, this 62% reduction claimed is far greater than the reduction of 11.9%”

This seems to be a pretty big overstatement of Rexulti’s effectiveness.

Reports of Ineffectiveness in People with Obesity

This overstatement is more troubling in light of a new publication by Caroline Apovian and colleagues telling us Rexulti may not work as well in people with obesity – who represent up to 60% of the people who need this drug.

Apovian et al reviewed issues with drug testing and labeling that often excludes people with obesity. These people represent 42% of the U.S. adult population – and even more for people with severe mental illness. In the case of  Rexulti, they found that self-reports indicate people who have taken brexpiprazole are more likely to describe it as ineffective for them if they have significant obesity.

This is consistent with earlier research showing that the recommended dosing for Rexulti from Otsuka makes it likely that people with obesity will achieve subtherapeutic drug levels.

A Bad Combination

Inflated effectiveness claims and inadequate clinical testing for an important drug is an unfortunate combination. We expect FDA will bring this under control. Vigilance about false advertising is part of the answer. Better directions for dosing in the drug label is another. Both of these can have an immediate effect.

The third and final part of the answer can begin now and the benefits will keep coming over the years. Requirements to test new drugs in persons who fully represent the population – including people with obesity – can be fully implemented to deliver safer and more effective drugs.

Click here for the new paper by Apovian et al and here for more on FDA concerns about overstated claims of effectiveness in advertising for Rexulti.

Inflating a Hot Air Balloon, photograph by Dietmar Rabich, licensed under CC BY-SA 4.0

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November 20, 2023