3 ms·
> if you're measuring a surrogate marker (that is an accepted proxy for clinical outcomes), you don't need a comparator arm Why is this the case? Wouldn’t ther
by ejstronge 8y ago
> if you're measuring a surrogate marker (that is an accepted proxy for clinical outcomes), you don't need a comparator arm
Why is this the case? Wouldn’t there be concerns that a study population might be different from the general population and thus require an internal control?
- refurb 8y agoHere is a good example of FDA guidance on the issue.[1] FDA acknowledges that FVIII levels can serve as a proxy for clinical outcome (reduced bleeding episodes) in hemophilia A. Our understanding of what is "normal" in FVIII blood levels is such that a single arm, surrogate biomarker study is sufficient for approval. [1]https://www.fda.gov/downloads/BiologicsBloodVaccines/GuidanceComplianceRegulatoryInformation/Guidances/CellularandGeneTherapy/UCM610801.pdf https://www.fda.gov/downloads/BiologicsBloodVaccines/Guidanc...
- ejstronge 8y agoCould you help by pointing out where they talk about not obtaining baseline/control data? After a quick glance, they only seem to mention using a within-subject design.
- refurb 8y agoSorry, misread your reply. Yes, they do an internal baseline/control, but don't have a control arm (either placebo or active comparator) in the trial. That was the focus of the JAMA article.