FDA Approves Amvuttra for ATTR-CM in Extended Label

Alnylam Pharmaceuticals announced that the FDA has approved their supplemental new drug application (sNDA) for Amvuttra (vutrisiran), for the treatment of the transthyretin amyloidosis with cardiomyopathy (ATTR-CM) in adults, according to a news release. This extended indication means Amvuttra is the first and only FDA-approved treatment for ATTR-CM and the polyneuropathy of hereditary transthyretin-mediated amyloidosis (hATTR-PN) in adults. Amvuttra was initially approved in the United States in 2022.

ATTR-CM is a rare, rapidly progressing and fatal disease in which misfolded transthyretin (TTR) proteins amyloid deposits collect in places such as the nerves, heart and gastrointestinal tract. There are two types of ATTR - hATTR-PN which affects about 50,000 people worldwide and wild-type ATTR, which affects between 200,000 and 300,000 people across the globe. Amvuttra works by silencing both mutant and wild-type transthyretin through RNA interference, thus eliminating mutations.

The approval for ATTR-CM patients is based on the results of the HELIOS-B Phase 3 clinical trial, presented at the European Society of Cardiology Congress and published in The New England Journal of Medicine. Results showed that Amvuttra decreased mortality and cardiovascular event risk by 28% over 36 months. Mortality was reduced by 36% over 42 months.

The HELIOS-B clinical trial tested safety and efficacy for hATTR-PN patients. The most common adverse reactions in hATTR-PN patients were pain in extremities (15%), arthralgia (11%) and dyspnea (7%). Amvuttra also carries a risk for vitamin A deficiency, reported by 7% of patients.

The recommended dosage of Amvuttra is a 25 mg subcutaneous injection every three months, according to the prescribing information.

“Despite recent advances, there remains a significant need for patients living with ATTR-CM and I’ve witnessed, firsthand, the impact that ATTR amyloidosis can have on families, including diminished quality of life and the loss of loved ones,” Muriel Finkel, president of the Amyloidosis Support Groups said in the release. “The availability of this groundbreaking treatment option is a significant moment for patients living with ATTR amyloidosis. It represents a beacon of hope for our community.”

Patients can find support and resources through Alnylam Assist. Amvuttra is covered for 99% of patients with hATTR-PN and most pay as little as $0 for their prescription, according to the release. Amvuttra has a whole sale acquisition cost of $119,351 per prefilled syringe.

“This FDA approval provides an opportunity to further transform ATTR-CM treatment with a new mechanism of action," Ronald Witteles, M.D., HELIOS-B investigator, professor of medicine at Stanford University School of Medicine and co-director of the Stanford Amyloid Center. "This is a very exciting day for patients with this challenging disease.”