Alec Walker

Q&A With Alec Walker, MD, DrPH, Principal, World Health Information Science Consultants, LLC
Advisor to the Reagan-Udall Foundation



What is the biggest challenge today for post-market surveillance?
First we need to define clearly the types of adverse drug effects for which the current systems permit sensitive surveillance and ready exclusion of false-positive signals. Many common, immediate and severe reactions already fall into this class, as do less frequent, less dramatic or more delayed drug effects for which there are no counterparts among spontenously occurring diseases. And for these "easy-to-find" effects, we need to let the existing systems work. The next order of business is to dissect the harder-to-study effects, to find out where the existing systems need to be adapted, in order to bring the effects under scrutiny. Screening available data to identify highly susceptible populations may be a solution. Find groups in whom the adverse effects are easy to identify and for whom the products involved ought to be contraindicated. Perhaps hardest of all will be to lay down criteria for the kinds of adverse effects for which surveillance is unlikely to be successful, and for which experimental studies or aggressive diagnostic approaches will be important.

What is your landmark or pioneering pharmacoepi article that you like to refer to?
I'd name two papers. The first I wrote with Bob Wise of the FDA. (Walker AM, Wise RP. Precautions for proactive surveillance. Pharmacoepidemiol Drug Safety 2002;11:17-20 ) We explored the challenges to active drug safety surveillace that were then clearly on the horizon, and now are with us. The second, led by colleagues now at the Brigham and Women's Hospital in Boston, provided an instance of detecting an difficult-to-find adverse effect using rich data a gamut of statistical techniques. (Schneeweiss S, Seeger JD, Landon J, Walker AM. Aprotinin during coronary-artery bypass grafting and risk of death. N Engl J Med 2008;358:771¬83)

What excites you about the IMEDS-Methods Research Agenda?
We have a coherent program that responds both to science and to the FDA's expressed needs.

IMEDS-Methods is important to me because ... it welcomes contributions from every corner of the drug safety arena, from regulators and researchers, from industry and consumers, and it provides an open arena where ideas can contend and the most successful ones can prosper.