> Surely this molecule can't just hang around for six months without being gobbled up by the liver or such. It can! The fluorines likely protect the metabolic

> Surely this molecule can't just hang around for six months without being gobbled up by the liver or such. It can! The fluorines likely protect the metabolic target. At that point you're relying on excretion of unchanged drug through the kidneys or liver (which excrete into bile, and then eliminated in feces). Google tells me the half-life of the subcutaneous administration is 2 to 3 months, so twice yearly injections makes sense.