Pharmacodynamic Study of CK-2017357 in Patients With Generalized Myasthenia Gravis

This study is a Phase II, double-blind, randomized, three-way crossover, placebo-controlled, PD study of CK-2017357 in patients with generalized MG on standard therapy. 36 to 78 patients will be randomized at approximately 15 study centers to one of six different treatment sequences. Each treatment sequence consists of three dosing periods in which patients receive single oral doses of placebo, 250 mg, and 500 mg of CK-2017357. All six treatment sequences will enroll 6 patients. A wash out period of at least 7 days (to a maximum of 10 days) will be employed between the individual doses for each patient. This study is designed to assess the effects of CK-2017357 on the standardized Quantitative Myasthenia Gravis (QMG) score, Manual Muscle Test, Myasthenia Gravis Composite Assessment (MGCA) and Forced Vital Capacity. The pharmacokinetic (PK) and pharmacodynamic (PD) relationship of CK-2017357 after two single doses will be assessed versus placebo.