Our Programs

Complement-Mediated Diseases

BioCryst discovered and is developing BCX10013, a novel, oral, potent and selective small molecule Factor D inhibitor that could offer significant therapeutic advances for patients with complement-mediated diseases.

The complement system is part of the body’s natural immune system and is responsible for helping the body eliminate microbes and damaged cells. It is comprised of proteins that are primarily produced in the liver and circulate in the blood. Once activated, the complement system stimulates inflammation, phagocytosis and cell lysis. Excessive or uncontrolled activation of the complement system can cause severe, and potentially fatal, immune and inflammatory disorders.

The complement system comprises biological cascades of amplifying enzyme cleavages involving more than 30 proteins and protein fragments and may be activated through three pathways:

  1. Classical pathway (CP, initiated by antibody-antigen complexes)
  2. Lectin pathway (LP, initiated by microbial surfaces)
  3. Alternative pathway (AP, constitutively active)


All three of these pathways share a common terminal pathway that culminates in formation of the cytolytic membrane attack complex (MAC). The alternative pathway also provides a critical amplification loop for these pathways, regardless of the initiating mechanism. Factor D is an essential enzyme in the alternative pathway, thus making Factor D an attractive target to address complement-mediated diseases.

Clinical Program

BioCryst has begun a clinical program with BCX10013. The preclinical and early clinical profile from healthy volunteers suggests BCX10013 could have the properties of a once-daily, oral therapy. A goal of the ongoing clinical program is to confirm this once-daily profile with healthy volunteer and patient data.

Additional Complement Targets

BioCryst is pursuing additional oral medicines directed at other targets across the classical, lectin and terminal pathways of the complement system. The goal of BioCryst’s overall complement program is to advance several oral compounds across multiple pathways in the complement system to treat many complement-mediated diseases.

BCX10013 is investigational and has not been deemed safe and effective by the FDA.