Study finds trials of prescription DTx often lack ‘rigour’

A retrospective analysis of the clinical data supporting 20 FDA-approved prescription digital therapeutics has found that they often fail to apply rigorous standards of evidence.

The study – published in the Health Affairs journal – concluded that just two of the FDA-approved prescription DTx that were on the market were supported by at least one randomised, blinded and controlled trial, the gold standard for medicinal products.

Moreover, eight (40%) of the products – which were not identified by the researchers – had no clinical trials corresponding with their FDA-approved indications.

Prescription DTx are regulated by the FDA under its Software as a Medical Device (SaMD) framework and are defined as digital tools that rely primarily on software for diagnosis or treatment.

The researchers found 20 prescription DTx authorised for use across 22 indications, with 117 clinical studies available to support them. Of these around 20% were observational and 38.5% were randomised controlled trials (RCTs), but more than two-thirds did not use any blinding, meaning the investigators and study subjects knew they were using the DTx.

More than 60% of RCTs that were undertaken did not have the results published on the US ClinicalTrials.gov register, which could be in violation of FDA regulations.

Two-thirds of clinical studies were conducted on a post-market basis and tended to use less rigorous standards of evidence than pre-market studies, while more than half did not report inclusivity data such as race or ethnicity and studies often excluded older adults and people not proficient in English, raising questions about their real-world applicability.

The findings come at a time when the prescription DTx sector is facing considerable challenges, with companies struggling to build a sustainable business even if they have multiple FDA-approved products on the market. One pioneer of the category, Akili, has said it will abandon the prescription market altogether and concentrate instead on a direct-to-consumer business model.

While most products in this category are approved via the FDA’s 510(k) pathway for medical devices, which generally does not require clinical data, companies developing prescription DTx are missing opportunities to generate high-quality evidence for their products before they enter the market, concludes the study.

The authors, from the University of California San Francisco (UCSF) and Yale University, note that “a stronger evidence base would increase confidence in these technologies’ effectiveness and would enable more informed decision making about their clinical use and coverage.”

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