Yesterday, the U.S. Food and Drug Administration (FDA) approved Pegzilarginase (Loargys) — the first and only treatment for Arginase 1 Deficiency (ARG1-D).

This is not just a milestone. This is hope realized.

For families living with ARG1-D, this approval represents something we have waited for, worked toward, advocated for, and prayed over for years — a treatment that can lower toxic arginine levels and help slow the devastating progression of this ultra-rare disease.

Today, we celebrate science, perseverance, and the power of community.

We extend our deepest gratitude to Immedica for their unwavering commitment to bringing Pegzilarginase (Loargys) through clinical development and regulatory approval. Your dedication to rare disease patients has changed lives.

To the brilliant researchers and scientists who refused to give up — your years of laboratory work, clinical trials, data analysis, and relentless pursuit of answers made this day possible.

To the physicians and clinical teams who cared for patients, conducted trials, and advocated fiercely on behalf of families — thank you for standing beside us every step of the way.

And most importantly — to the families.

  • To the parents who enrolled their children in clinical trials.
  • To the patients who showed extraordinary courage.
  • To the caregivers who filled out surveys, wrote letters, spoke to regulators, traveled to study sites, and shared deeply personal stories to help the world understand ARG1-D.

You are the reason this happened.

This approval belongs to you.

The journey was long. It was emotional. It was uncertain at times. But this community never stopped believing that treatment was possible — and never stopped fighting for it.

Today we honor every voice that spoke up, every advocate who showed up, and every family who held on through the hardest days.

Pegzilarginase (Loargys) is now approved in the United States — and for the first time in history, patients with Arginase 1 Deficiency have an FDA-approved treatment option.

  • This is progress.
  • This is momentum.
  • This is hope.

And we are not done yet.

With profound gratitude and love,

Christine Zahn
Arginase 1 Deficiency Foundation