By Rachael King, CEO, CRF Health
Over the past year or so, there has been much discussion on the various PRO modalities available for use in clinical trials – eDiary, IVR, digital pen, mPRO, webdiary, SMS based systems and of course (and still very prevalent), paper. The debate has raged as to which method is best, and for which phase of study; therapeutic area; subject age range; country and possibly even phase of the moon. But the question I've been asked repeatedly, especially since the launch of our web diary, is not about method selection but, "Can we mix them?"
We should remember there could be very good reasons to use mixed modalities – cost, internet availability, KOL opinion, timelines etc. These reasons are of rather more importance to the Sponsor than the regulators. As a scientist, I want to say, "No, don't do it." My basic training has always been to reduce variables to a minimum, even if you thought they made no difference. Easier done in the laboratory than in the real world of clinical trials; but an aspiration none the less. I am not convinced that strict enforcement of a single modality is a pragmatic approach. My answer has always been, if the PRO is not collecting primary or secondary endpoint data or being used to substantiate a labelling claim, and the instrument can be presented in a useable and user friendly way in all the selected modalities, go ahead and mix. If the answer to any of these questions is no, then, at a minimum, some evidence of equivalence will be required, and the level of evidence probably depends on the importance of the PRO data.