Pegzilarginase can be used, within its marketing authorisation, as an option to treat arginase‑1 deficiency (also called hyperargininaemia) in people 2 years and over. Pegzilarginase can only be used if the company provides it according to the commercial arrangement.
Pegzilarginase must be funded in the NHS in England for the condition and population in the recommendations, if it is considered the most suitable treatment option. Pegzilarginase must be funded in England within 90 days of final publication of this guidance.
There is enough evidence to show that pegzilarginase provides benefits and value for money, so it can be used routinely across the NHS in this population.
Usual treatment for arginase‑1 deficiency includes dietary protein restrictions, essential amino acid supplementation and ammonia-lowering drugs. Pegzilarginase is the first treatment that specifically treats arginase‑1 deficiency.
Clinical trial evidence shows that pegzilarginase plus usual treatment reduces levels of arginine in the blood compared with placebo plus usual treatment. Evidence also suggests improvements in mobility and mental processing, but this is uncertain because the studies were small and short. So, it is unclear how large these benefits are or how long these improvements will last.
Despite the uncertainties in the clinical and economic evidence, the most likely cost-effectiveness estimates are within the range that NICE considers an acceptable use of NHS resources for highly specialised technologies. So, pegzilarginase can be used.