https://www.wsj.com/articles/fda-food-and-drug-admin-arg1-d-pegzilarginase-aeglea-biotherapeutics-arginine-deficiency-healthcare-c9e8c21f?mod=opinion_lead_pos6
We’ve spent most of our medical careers investigating and treating rare genetic conditions, including some afflicting only a few dozen Americans. Recently, scientists developed a treatment for one such condition—arginase 1 deficiency, or ARG1-D, which causes the amino acid arginine to accumulate in the blood, harming the brain and causing seizures, stunted growth and intellectual disability. The Food and Drug Administration has refused to consider the therapy. Its decision ignores the best available data and indicates a lack of understanding of rare-disease research.
Discovering treatments for rare diseases is a daunting task. Recruiting even a few dozen people for a clinical trial requires doctors and drug companies to identify a large share of the patient population. And since the market for such therapies is necessarily small, it’s nearly impossible to attract investment. So when news emerged aboutAeglea BioTherapeutics’ ARG1-D therapy pegzilarginase, we could hardly believe it. Pegzilarginase is an enzyme engineered to lower the body’s levels of arginine. The randomized placebo-controlled study of pegzilarginase included 32 patients with ARG1-D.
The results speak for themselves. The amount of arginine present in blood plasma declined by 80% for patients on pegzilarginase. After only six months, 90.5% of patients who received pegzilarginase had normal arginine levels, and this was sustained over time. The data also suggested progressive improvements in motor function compared with a placebo. And most patients tolerated the therapy quite well.
These numbers were jaw-dropping. Which is why the FDA’s decision is incomprehensible.