FDA convened last week's meeting of its Cardiovascular and Renal Drugs Advisory Committee after the three companies that market phosphate binders to treat hyperphosphatemia in dialysis patients asked for guidance on extending the labels of the products to advanced chronic kidney disease patients not yet on dialysis. But if the companies were hoping for clarity, what they got instead was a mixed message that sounded a bit like "do as I do, not as I say."
The committee rejected the sponsors' contention that there is sufficient evidence to consider reduction in phosphate levels a validated surrogate marker of clinical benefit. On the other hand, the panel felt that there were enough data of other sorts - epidemiological and observational - and a sufficiently strong biological rationale to allow the label extension.
In the end, clinical experience prevailed, as committee members concluded patients shouldn't have to wait while companies obtain new clinical evidence to support the indication, which would about double the number of CKD patients targeted for treatment (see "Chronic Kidney Disease Staging," A5).
What the FDA will do now is anyone's guess, but the medical community has already embraced earlier use of the products. According to Steven Findlay, managing editor of Consumer Reports Best Buy Drugs, 40% of pre-dialysis patients in the U.S. are taking phosphate binders. Findlay, a consumer representative for the panel, was a voting member of the committee.
Looking for guidance
All three companies that market phosphate binders to treat hyperphosphatemia