Standard of Evidence Expanded in New FDA Guidance

December 31, 2019

The FDA proposed broadening its definition of the standard of evidence for effectiveness of investigational drugs and increasing the range of acceptable trial design, especially in rare disease research.

In its first updated guidance in more than 20 years on acceptable trial design, the FDA said substantial evidence from a trial proving effectiveness could be gained from one trial instead of two, one adequate well-controlled trial plus confirmatory evidence or reliance on a previous finding of effectiveness from an approved drug. 

The FDA has decided that in some cases the traditional two-trial model can be replaced by other types of trial designs more suited to the study of rare diseases. Although randomized, double-blinded, concurrently controlled superiority trials are regarded as the most rigorous trial design, five types of control are mentioned in the draft guidance: placebo, dose comparison, no treatment, active treatment and historical control.

Comments on the draft guidance are due Feb. 21, 2020.

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