BCX10013, an oral factor D inhibitor for multiple complement-mediated diseases, led to a rapid, sustained, and effective suppression of the alternative pathway of the complement system in healthy volunteers.

Given the positive results of the ongoing phase 1 study, BioCryst Pharmaceuticals plans to start evaluating once-daily BCX10013 treatment in patients with paroxysmal nocturnal hemoglobinuria (PNH) in mid-2023.

“Our next step is to gather data from a small number of patients, utilizing the excellent biomarkers in PNH, to quickly confirm optimal clinical dosing this year,” Helen Thackray, MD, chief research and development officer at BioCryst, said in a press release. “We then plan to rapidly advance the program into pivotal trials in multiple complement-mediated diseases, beginning next year with [immunoglobulin A nephropathy].”

A single 110 mg dose of BCX10013, the highest dose studied to date, led to a 97.8% suppression of the alternative pathway 24 hours post-dose. Moreover, it seems to be safe and generally well-tolerated.

“We believe BCX10013 has the potential to be a best-in-class treatment option with an oral, once-daily profile,” Dr. Thackray said.

Participants received a single dose of 1 mg, 3 mg, 10 mg, 40 mg, 80 mg, or 110 mg of oral BCX10013 or placebo in the single ascending dose study, and 20 mg, 40 mg, or 80 mg of oral BCX10013 or placebo administered once daily for 7 days (20 mg cohort) or 14 days (40 mg and 80 mg cohorts) in the multiple ascending dose study.

The onset of inhibition of the alternative pathway occurred within 1 hour and increased in a dose-dependent manner, according to the company press release.

“We believe that our ability to develop oral medicines as monotherapy against targets across multiple complement pathways, in addition to the alternative pathway, could allow us to help more patients with distinctly different complement-mediated rare diseases,” Dr. Thackray said.

“With our oral approach, BioCryst also has the opportunity to develop combination therapies to improve therapeutic options for those diseases affecting multiple pathways of the complement system.”


BioCryst reports initial clinical data with oral factor D inhibitor BCX10013 supporting development as a once-daily treatment for complement-mediated diseases. News release. BioCryst Pharmaceuticals, Inc; January 9, 2023.