Pegcetacoplan

How it works

Traps C3, the hub of the complement cascade that destroys red blood cells in the rare disease PNH. Stopped near the source.

What it's made of

Two 15-amino-acid peptides at the ends of a 40 kDa PEG chain. They come from compstatin, a ring of 13 found in 1996 in a phage library. The PEG makes it last.

What it's for

Prescribed for

Paroxysmal nocturnal hemoglobinuria (PNH) in adults; in the US, also two rare kidney diseases from age 12 and, in the eye, geographic atrophy.