Alnylam Pharmaceuticals Submits New Drug Application for Experimental Acute Hepatic Porphyria Drug

According to a press release from Alnylam Pharmaceuticals, the Massachusetts-based biopharmaceutical company has completed the submission of its New Drug Application (NDA) for givosiran — its experimental acute hepatic porphyria drug.

Givosiran has received Breakthrough Therapy and Orphan Drug designations in the United States, along with Priority Medicines and Orphan Drug designations in the European Union. Alnylam expects to submit a Marketing Authorisation Application (the European equivalent of the NDA) in the immediate future.

About Acute Hepatic Porphyria

Porphyria is a group of disorders caused by the build-up of an essential substance called porphyrin, and subsequently a lack of heme. Porphyrins are an important building block in heme construction, and their ferrous characteristics are what give blood its red hue. Heme, itself a vital component of hemoglobin, is responsible for blood’s oxygen-carrying abilities.

Imbalances in porphyrins, it follows, can result in heme shortages — a characteristic complication of porphyria. The production of heme involves eight different liver and bone marrow enzymes. Deficiencies in these enzymes lead to different types of porphyria.

Acute hepatic porphyria (AHP) is a sub-group of porphyria characterized by neuro-visceral attacks, which affect organs in the abdominal and thoracic cavities — even the skin, in some cases. These attacks cause flare-ups in the nerves of the viscera, commonly causing intense abdominal pain (appearing in 85-95% of cases), neurological dysfunction (muscle weakness, sensory loss), and psychological distress (irritability, anxiety, sometimes hallucination). These attacks are often triggered by external stimuli (like alcohol or stress), but can also be rooted in internal chemistry (hormonal changes).

Management of AHP is primarily preventative. When a neuro-visceral attack can’t be avoided by controlling external factors, an emergency injection of human hemin or carbohydrates is required.

Women are much more likely to be affected as men — as many as 80% of cases in Europe are found to affect women. It’s believed that as many as one person in every 75,000 has some time of acute hepatic porphyria.

Givosiran’s New Drug Application Filed

Givosiran, Alnylam’s experimental acute hepatic porphyria drug, is designed as a once-monthly subcutaneous injection. Though not a cure for the condition, givosiran works by interfering with certain RNA signatures to reduce the likelihood of experiencing a neuro-visceral attack.

The successful conclusion of Alnylam’s phase 3 study of givosiran in AHP patients prompted the drug manufacturer to submit a New Drug Application to the US Food and Drug Administration (FDA). The New Drug Application is the final step on the clinical trail to drug marketing in the United States — if the FDA approves the application, givosiran will be cleared for use in the United States. Alnylam expects to submit a Marketing Authorisation Application in Europe sometime mid-2019, which would mean sometime in the immediate future.


Do you or does someone you know live with acute hepatic porphyria? What do you think of this exciting news? Patient Worthy wants to hear from you!

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