Rare Disease

There are over 7,000 rare diseases, of which only 5% have an approved treatment.1 We hope to help change this reality for patients and communities living with rare, complement-driven diseases.

In 2021, we brought forward the first new class of complement medicine in nearly 15 years with the approval of a treatment for PNH, a rare and potentially life-threatening blood disease.

Living with PNH

Our progress in PNH is only the beginning. Building on our approach to target C3, we have several later-stage clinical programs ongoing in rare diseases with few or no treatment options.

We strive to understand the unique challenges people with rare diseases face and are committed to always putting patients first. This includes embedding the perspectives and needs of patients and their communities into our business decisions from research to clinical development and commercialization, and ensuring those who need our medicine have access as quickly as possible.

Advancing therapies across several rare diseases

Paroxysmal Nocturnal Hemoglobinuria (PNH)

PNH is an acquired, rare, chronic, and potentially life-threatening blood disease that can appear at any age and in any race or gender, and is most often diagnosed in people in their early 30s.

Learn more » Learn more about our ongoing clinical trials »

Immune Complex Membranoproliferative Glomerulonephritis (IC-MPGN) and C3 Glomerulopathy (C3G)

IC-MPGN and C3G are rare kidney diseases that cause inflammation and damage to the organ. There are no medicines currently approved to treat IC-MPGN or C3G.

Learn more » Learn more about our ongoing clinical trials »

Cold Agglutinin Disease (CAD)

CAD is a chronic, rare blood disorder where the body’s immune system attacks and destroys its own red blood cells by mistake. There are limited treatment options for CAD, which can result in anemia, chest pain, and the need for frequent transfusions.

Learn more >> Learn more about our ongoing clinical trials »

Hematopoietic Stem Cell Transplantation-Associated Thrombotic Microangiopathy (HSCT-TMA)

HSCT-TMA is a rare blood disease that can result from a bone marrow transplant complication and lead to organ damage. There are currently no approved treatments for HSCT-TMA.

Learn more » Learn more about our ongoing clinical trials »


  1. NIH’s National Center for Advancing Translational Sciences