Alnylam announced that their investigational treatment givosiran (ALN-AS1), for the prophylaxis of attacks in patients with acute hepatic porphyria (AHP), has been granted Breakthrough Therapy designation by the Food and Drug Administration (FDA).

The porphyrias are a family of rare metabolic disorders with mostly autosomal dominant inheritance predominantly caused by a genetic mutation in one of the eight enzymes responsible for heme biosynthesis. Acute hepatic porphyrias (AHP) constitute a subset where the enzyme deficiency occurs within the liver, and includes acute intermittent porphyria (AIP), hereditary coproporphyria (HCP), and variegate porphyria (VP).

Depending on the specific type, AHP patients can suffer from a range of symptoms including acute and/or recurrent life-threatening attacks with severe abdominal pain, peripheral and autonomic neuropathy, neuropsychiatric manifestations, cutaneous lesions and possibly paralysis and death if left untreated or if there are delays in treatment. 

Related Articles

Ongoing data results from a Phase 1 study demonstrated a reduction in both frequency and number of porphyria attacks with givosiran. Updated results from this trial will be released later this month.

Currently, the only approved treatment for AHP attacks is hemin for injection (Panhematin or Normosang). The initial Phase 1 data also indicated that those treated with givosiran required less annualized hemin doses.

“We believe givosiran could become a transformative treatment for patients with this devastating and potentially life-threatening disease,” said Jeff Miller, VP of the givosiran program at Alnylam. “We plan to initiate a Phase 3 clinical program with givosiran in late 2017.”

For more information visit