Response-adaptive randomization makes clinical trials more attractive to eligible patients

Taking the random out

New approach may boost clinical trial participation

issue 22 | Fall 2014

It's a classic Catch-22. The gold standard for clinical trials of new treatments involves random assignment of participants, but many candidates aren't willing to accept 50/50 random odds. The trial's recruitment lags, slowing the effort to improve treatment through research.

That's why University of Michigan physicians are leading efforts to test and adopt an approach that takes some of the "random" out of the process, while preserving the ability to compare treatments. Instead of every patient receiving a randomly chosen treatment, the approach adjusts the odds as the study progresses. If early results suggest better efficacy from one of the candidate treatments, each new patient's odds of getting that option increase. It's called response-adaptive randomization, or RAR.

In the journal Stroke, U-M researchers report the results of how 418 emergency department patients responded to the two approaches to trial design. The researchers asked the patients to imagine they had just suffered a stroke, showed them a video describing a study that needed stroke patients, and asked them whether they would volunteer for that study if they had really just had a stroke.

Half the patients saw a video describing a classic randomized study, and half saw the same video but with an added section describing an RAR approach. Only 54 percent of the people shown the first video said they would volunteer for the study. But 67 percent of those shown the RAR video said they'd enroll.

If the results play out in real emergency stroke studies, this 13-point difference could make a big difference in the pace of medical research, says William Meurer, M.D., M.S., the U-M emergency physician who led the study.

"Although this is a hypothetical scenario, it shows we might increase recruitment for acute stroke studies using a response-adaptive randomization design," Meurer says. "This could be especially important in emergency situations, when patients or their loved ones have just minutes to consider options."