Clinical development programs not only provide data necessary for regulatory approval, but also data on which prescribing decisions are based. Demonstrating efficacy is a regulatory issue, but comparing a product to placebo, standard care, or a competing approved product is a decision that could affect eventual market share.

Armed with positive Phase II data for its Thymoglobulin rabbit anti-thymocyte globulin in organ transplant, SangStat Medical Corp. will now consider what message to send the market with its pivotal studies. Although it is more difficult to show efficacy when comparing one antibody product to another instead of to placebo, "you want to show physicians in clinical practice a comparison to an existing standard of care," said SANG Chairman and CEO Philippe Pouletty.