C3 is a drug-conjugate consisting of two parts the targeting moiety, and the drug moiety. The targeting moiety is a novel proprietary molecule that has high-affinity to bone. The drug moiety is a prostaglandin analog that acts on PGE2 receptor 4, an EP4 agonist. These two moieties are cleaved by blood-enzymes with a half-life of 1 week. In illustrations each moiety is represented as a hexagon.
How C3 works