Most Post-Marketing Studies Deliver ''Duh'' Data

Post-marketing studies--at the forefront of congressional debate around the Prescription Drug User Fee Act (PDUFA)--may not yield eye-opening results for most sponsors, a new study has found.

A recent analysis from the Tufts Center for the Study of Drug Development (CSDD) suggests that these much-ballyhooed studies are not only expensive and hard to complete on time but, for all that, not very informative. Yet no news is often good news in the post-marketing stage--and that may offer encouragement for drug companies to start fulfilling their commitment to complete these studies.

Only 32 percent of respondents said post-marketing clinical studies ''significantly or very significantly'' added to their knowledge of a product's safety and quality, while the majority of both clinical and non-clinical study sponsors (68 percent and 79 percent, respectively) said post-marketing studies ''contributed either marginally or not at all'' to their understanding of the product.

CSDD Associate Director Christopher-Paul Milne said the results are neither unexpected nor as bad as they sound. ''You could look at this two ways,'' said Milne, who co-conducted the study. ''One way is that 68 percent of these sponsors aren't finding any surprises in their product--good ones or bad ones.'' The other way, he says, is that 32 percent of the sponsors are finding previously unknown side effects or new uses for their drugs.

And that's an added value of post-marketing surveillance--to explore possible new avenues for development. In non-clinical studies, including animal testing and chemical manufacturing, Milne said that new findings are uncommon because such testing has already been done in early R&D. Clinical studies with human subjects are where the significant data emerge, which explains why there are about twice as many clinical than non-clinical studies conducted.

But the real problem lies in the difficulties post-marketing studies present, rather than any potential lack of relevant results. According to the CSDD study, 45 percent of these studies were delayed, and 56 percent of the delayed studies needed ''at least a year beyond their expected completion date'' to finish. And sometimes, Milne said, the FDA asks too much: Genentech's Avastin (bevacizumab) had to go through 20 post-marketing studies to win approval for use in colorectal cancer patients. At $5.3 million a pop for clinical studies and $610,000 per non-clinical study, that's a steep price for one new application for a single drug.

But Milne noted that the way to minimize these extra costs and time crunches is to start a scientific dialogue with FDA during the approval process. ''This isn't just something that will go away,'' he said. ''Both sides have work to do.''

And for foot-dragging companies that ignore the carrot, PDUFA is set to give FDA a stick to prod them into compliance. Whether or not the agency will choose to use it remains to be seen.