When SangStat Medical Corp. began a bioequivalence study of its SangCya oral cyclosporine solution, the company was not sure whether the product would show bioequivalence to Novartis AG's Sandimmune cyclosporine or second generation product, Neoral. Therefore, SANG opted to mix its product with chocolate milk, as was common practice for delivering Sandimmune.

As it turned out, the study showed SangCya to be bioequivalent to Neoral. Yet the FDA never required SANG to run a study of SangCya with apple juice, the recommended Neoral delivery mixture. But perhaps such a trial would have been warranted, as SANG last week withdrew SangCya from the U.S. market after a study showing that the two products, when mixed with apple juice, were in fact not bioequivalent.