FDA approves drug with annual cost of $442,000 for rare genetic disorder

The FDA has approved the drug Givlaari, made by Alnylam Pharmaceuticals, for adults who have acute hepatic porphyria, a genetic disorder that leads to severe abdominal pain and affects just 1 in 25,000 people.

The big picture: Alnylam set Givlaari's net price, after discounts to insurers, at $442,000 per year, or about $39,000 per vial. It's a lofty price tag, but those prices are common among drugs that use new scientific techniques to treat very rare diseases.

What they're saying: Alnylam CEO John Maraganore told Bloomberg that the company will adjust the drug's price based on its results.

• "If patients respond well, we will be fully paid. If they don't have an acceptable response to the drug, we will give a rebate back to the payer," he said.

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