The Food and Drug Administration (FDA) has granted Orphan Drug designation to NTLA-2001 for the treatment of transthyretin (ATTR) amyloidosis.

ATTR amyloidosis is a rare, progressive, life-threatening disease caused by mutations in the transthyretin (TTR) gene resulting in the production of structurally abnormal TTR protein with a propensity to misfold. The damaged proteins build up as amyloid deposits in the body causing complications in multiple tissues including the heart, nerves and digestive system.

Using CRISPR/Cas9 technology, the investigational therapy is designed to edit disease-causing genes inside the human body. Administered via a single intravenous infusion, NTLA-2001 inactivates the TTR gene in liver cells preventing the production of misfolded TTR protein. 

The Company is currently evaluating the efficacy and safety of NTLA-2001 in adults with hereditary ATTR amyloidosis with polyneuropathy in a phase 1 clinical study ( Identifier: NCT04601051). Interim results showed that treatment with NTLA-2001 led to an 87% mean reduction in serum TTR, with a maximum 96% serum TTR reduction by day 28, in 6 patients.

The FDA’s Orphan Drug designation is granted to medicines intended to treat or prevent rare diseases or disorders that affect fewer than 200,000 individuals.

“Orphan Drug designation underscores the FDA’s recognition of NTLA-2001’s potential promise as a single-dose, novel therapy for the treatment of ATTR amyloidosis,” said Intellia President and Chief Executive Officer John Leonard, MD.


  1. Intellia Therapeutics receives US FDA Orphan Drug designation for NTLA-2001, an investigational CRISPR therapy for the treatment of transthyretin (ATTR) amyloidosis. News release. Intellia Therapeutics, Inc. Accessed October 22, 2021.
  2. Gillmore JD, Gane E, Taubel J, et al. CRISPR-Cas9 in vivo gene editing for transthyretin amyloidosis. N Engl J Med. Published online August 5, 2021. doi: 10.1056/NEJMoa2107454