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Exploratory trials, surrogate endpoints: not a robust basis for marketing authorisation

To serve the best interests of patients, it is more necessary than ever to base marketing authorisation decisions on robust data.

Many marketing authorisations are based on clinical trials in which the effects of the drug are assessed on the basis of surrogate endpoints or "exploratory" trials.

A US review of clinical trials of cancer drugs has shown that there is rarely a strong correlation between surrogate endpoints, in particular time to disease progression, and overall survival, which is a more relevant outcome.

Another study examined 36 cancer drugs that had been approved in the US between 2008 and 2012 on the basis of favourable effects on surrogate endpoints. Subsequent trials of the same drugs showed that only five prolonged survival.

In another study, the US Food and Drug Administration analysed the 22 drugs for which favourable results in exploratory (phase II) trials were contradicted by subsequent (phase III) trials, which showed a lack of efficacy and/or greater toxicity.

Results based on surrogate endpoints or derived from exploratory studies are too poorly predictive to serve as a basis for granting marketing authorisation.

To serve the best interests of patients, it is more necessary than ever to base marketing authorisation decisions on robust data.

"Exploratory trials, surrogate endpoints: not a robust basis for marketing authorisation" Prescrire Int 2018; 27 (193): 137-138. (Pdf, subscribers only).

Download the full review.
Pdf, subscribers only

See also:

New cancer drugs:
poorly evaluated,
ineffective and overpriced
(May 2018)
Free