Ultragenyx reported that its gene therapy candidate met a co‑primary endpoint in a Phase 3 study for a urea cycle disorder, showing a statistically significant reduction in blood ammonia levels. The trial enrolled adults with ornithine transcarbamylase deficiency and the company described the readout as a key clinical milestone toward potential regulatory filings. Ultragenyx framed the result as a pivotal step for a rare metabolic disease with high unmet need; the company will use the data to support regulatory interactions and next development steps. The result also underscores the ongoing maturation of systemic gene therapies for inherited metabolic disorders and will influence investor and partner interest in similar programs.