Amvuttra listed for reimbursement in Korea

RNAi-based suppression of TTR production…administered once every three months

Average of 3.7 years until diagnosis…importance of early suspicion and diagnosis emphasized

The treatment landscape for hereditary transthyretin amyloid polyneuropathy (hATTR-PN), a rare inherited disease, is beginning to show signs of change.

Given the nature of the disease, which takes several years from symptom onset to diagnosis and leads to rapid functional decline, the importance of early diagnosis and intervention is growing. Expectations are also rising for improved treatment access following reimbursement coverage for the RNA interference (RNAi)-based therapy ‘Amvuttra (vutrisiran).’

On the 27th, Medison Pharmaceuticals held a press conference at the Plaza Hotel in Jung-gu, Seoul, to commemorate the domestic launch of Amvuttra for the treatment of hATTR-PN.

(From left: Professor Jeeyoung Oh (Department of Neurology, Konkuk University Hospital), and Professor Gyeongmo Sohn (Department of Neurology, Haeundae Paik Hospital)

Hereditary transthyretin amyloid polyneuropathy (hATTR-PN) is a rare disease in which structurally abnormal transthyretin (TTR) proteins transform into amyloid forms and accumulate in various organs, including peripheral nerves, autonomic nerves, and the heart, causing nerve damage and organ dysfunction.

This disease is characterized by a complex combination of systemic symptoms, including not only peripheral sensory and motor neuropathy but also autonomic dysfunction, cardiovascular abnormalities, and gastrointestinal symptoms. A substantial number of Korean patients reportedly present with mixed phenotypes involving both neurologic and cardiac symptoms.

Delayed diagnosis is considered one of the biggest challenges. Early symptoms such as numbness in the hands and feet, sensory abnormalities, and gastrointestinal symptoms are relatively nonspecific and are often mistaken for other diseases. In Korea, the average time from symptom onset to diagnosis is reported to be 3.7 years.

Professor Gyeongmo Sohn of Haeundae Paik Hospital said, “hATTR-PN often begins with early sensory abnormalities, gastrointestinal problems, or weakness of finger muscles. It is important to recognize so-called ‘red flags’ such as family history, vitreous opacity, carpal tunnel syndrome (CTS), and autonomic symptoms at an early stage.”

He continued, “Autonomic symptoms such as dizziness caused by orthostatic hypotension, gastrointestinal motility disorders, and sexual dysfunction often appear even before motor nerve damage occurs. Early suspicion and diagnosis have a significant impact on patient prognosis.”

The disease also progresses rapidly. According to Professor Sohn, the median survival after diagnosis for hATTR-PN patients is approximately 4.7 years, shortening to about 3.4 years when cardiomyopathy is present.

RNAi-based Amvuttra added to reimbursement list… “Goal is to suppress disease progression”

Treatment of hATTR-PN in Korea broadly involves gene silencers and protein stabilizers. Currently approved treatments include the RNAi-based gene silencer Amvuttra and Pfizer’s TTR stabilizer Vyndamax (tafamidis).

Amvuttra is a therapy that suppresses the production of abnormal TTR proteins via RNA interference. It is considered a disease-modifying treatment because it fundamentally lowers production of the disease-causing protein and slows disease progression. Another key feature is that it can be administered as a subcutaneous injection once every three months.

After receiving Korean approval in November 2024, Amvuttra additionally gained approval in March this year for reducing cardiovascular death, hospitalization, and urgent heart failure visits in adult patients with wild-type or hereditary transthyretin amyloid cardiomyopathy (ATTR-CM).

Furthermore, as of April 1, health insurance coverage was extended to include Stage 1 patients with hATTR-PN for whom Vyndamax was insufficiently effective or difficult to administer, as well as all Stage 2 patients regardless of prior treatment status.

Amvuttra’s clinical efficacy was confirmed through the global Phase III HELIOS-A study. This study was conducted on 164 hATTR-PN patients across 22 countries.

Trial results showed that at 18 months, the Amvuttra treatment group exhibited a 0.46-point reduction in the Modified Neuropathy Impairment Score +7 (mNIS+7) compared to baseline, whereas the external placebo control group showed a 28.1-point increase.

Improvements were also observed in the quality of life and physical function. The treatment group showed statistically significant improvements in the Norfolk Quality of Life-Diabetic Neuropathy (Norfolk QoL-DN) score compared to the external placebo group, and preservation of function was also seen in the 10-meter walk test assessing ambulatory ability.

Professor Jeeyoung Oh, Department of Neurology at Konkuk University Hospital, said, “Amvuttra has demonstrated data showing improvements in neurologic function and quality of life in clinical studies. Because both physicians and patients have long faced significant unmet needs due to limitations in treatment accessibility, we hope reimbursement coverage will allow patients to receive treatment benefits at more appropriate stages.”