The US FDA has approved a Special Protocol Assessment (SPA) for the two replicate Phase 3 clinical trials for Savient Pharmaceuticals' lead drug, Puricase. The company held its phase 3 clinical investigators meeting at the end of March and plans to begin patient dosing in May.

Christopher G. Clement, president and CEO of Savient commented, "This final step in the formal process to receive approval from the FDA on our SPA for the Phase 3 trials for Puricase is a major milestone for the company. It allows us to remain on track for commercialization of Puricase with a BLA filing with the FDA targeted for late 2007."

Zeb Horowitz, Savient chief medical officer said, "The finalization of the SPA is very important to us, because it is a formal, written agreement with the FDA Review Division on the design, execution, and analysis of the Phase 3 pivotal studies in the Orphan gout (treatment-failure) population. Because our approach to the treatment of gout is novel, upfront agreement with FDA on the registration studies became a crucial component of our development strategy."

According to the company release, the phase 3 program is designed to compare the safety and efficacy of Puricase administered by two-hour intravenous infusion every two weeks or every four weeks versus placebo infusion, over a six-month period. The program design consists of two replicate six-month placebo-controlled trials of approximately 100 randomized patients each. All patients who complete the placebo-controlled trials will be invited to participate in a long-term open label extension, which the FDA suggested to continue for two years. Therefore, patients who are randomized to the placebo arms will be eligible to receive Puricase (PEG-uricase) treatment in an open label extension trial following completion of the six-month controlled registration trial.

Each of the two trials is independently powered for the primary efficacy (or key registration) endpoint, a responder analysis assessing the proportion of patients who have normalized plasma uric acid at month 3 and month 6. Secondary efficacy endpoints will be assessed in a population pooled from the two trials. These endpoints will include an assessment of the reduction in burden of gout tophi using digital photography, reduction in the frequency of gout flares, improvement in the count of swollen and tender joints, and improvements in patient reported outcomes using the Short Form 36 and the Health Assessment Questionnaire-Disability Index, stated the release.