This is a randomized, placebo-controlled, double-blind, parallel-group, 2-part study. Parts 1 and 2 will be conducted in the same subjects.~Part 1 of the study is designed to evaluate the efficacy, safety, and tolerability of treatment with oral BCX9930 monotherapy for 12 weeks versus placebo in subjects with PNH who are not currently receiving treatment with complement inhibitor therapy. Subjects will be randomized to receive BCX9930 or placebo under double blind conditions for the 12-week randomized treatment period. The primary efficacy and safety analyses will be based on Part 1.~Part 2 of the study is designed to evaluate the long-term safety, tolerability, and effectiveness of open-label BCX9930 monotherapy when administered through Week 52. All subjects in Part 2 will receive BCX9930. Subjects who are randomized to BCX9930 monotherapy in Part 1 will continue to receive BCX9930 in Part 2. Subjects who are randomized to placebo in Part 1 will discontinue that therapy at the Week 12 visit and receive BCX9930 in Part 2.
The purpose of this study is to determine the efficacy and safety of BCX9930 monotherapy for the treatment of adult patients with PNH not currently receiving complement inhibitor therapy.