This is a randomized, double-blind, placebo-controlled study designed to evaluate the safety, tolerability, and efficacy of multiple doses of sarizotan in patients with Rett syndrome with respiratory abnormalities. The study participants will be randomized to either sarizotan between 2 and 10 mg bid or placebo bid, based on age and weight criteria.
All patients who have completed the final evaluations at Week 24 (Day 168) and have no safety or tolerability issues that would preclude continuing on the study medication and have been compliant with the trial requirements will have the option of continuing open-label treatment with Sarizotan for up to 168 weeks.