Our Science

Leaders in Complement

At Apellis, we advance courageous science to deliver life-changing medicines across a broad range of serious diseases. Our world-class researchers have studied complement for over 20 years and are leaders in targeted C3 therapies.

The Complement Cascade

The complement cascade, or complement, is part of the immune system that defends the body against infection. When functioning normally, its role is to recognize and eliminate pathogens and damaged cells.

However, when complement is overactivated, it can attack and destroy healthy cells and tissues, leading to numerous serious diseases.

Targeting C3

Controlling complement begins at C3, the central protein of the complement cascade.

C3 is the only target in the cascade that addresses all three activation pathways that can initiate and drive disease. Targeting C3 may therefore offer comprehensive control of complement and diseases driven by excessive complement activation.

Diagram that illustrates the 3 pathways of complement activation, the essential role of C3 complement, and the effect of APL-2 (pegcetacoplan) on C3 activation

Pegcetacoplan (APL-2)

We are developing pegcetacoplan, a first-in-class, investigational targeted C3 therapy for diseases that have few or no treatments today.

Pegcetacoplan is the only targeted C3 therapy in late-stage development. The concept of targeting C3 has been validated, as pegcetacoplan has shown positive Phase 3 data in paroxysmal nocturnal hemoglobinuria (PNH), a rare blood disease.

Our programs across hematology, ophthalmology, nephrology, and neurology are only the beginning of what is possible with a targeted C3 therapy.

By controlling complement at the level of C3, we aim to make a difference in the lives of millions of patients around the world.

Federico Grossi, M.D., Ph.D., Chief Medical Officer of Apellis