Horn Howard sold $117K of RARE

Ultragenyx Pharmaceutical Inc. (RARE) shares rose 13% during trading and 3% after-hours after the FDA approved Fayuvi, a gene therapy for Sanfilippo syndrome type A. The stock had previously hit a 52-week low. The therapy, priced at $3.95 million per patient, is Ultragenyx's second gene therapy approval. Retail sentiment on Stocktwits turned 'extremely bullish'.

Ultragenyx (RARE) received FDA approval for its gene therapy Fayuvi, the first treatment for Type A Sanfilippo syndrome. The company's P/S ratio is 2.09, below its historical median of 16.1x. GuruFocus estimates RARE is 68.1% undervalued at $14.50 per share, but notes risks due to ongoing losses and cash burn. Insiders have sold $4.0M in shares in the past year.

Ultragenyx Pharmaceutical Inc. (RARE) filed an SEC Form 8-K — Other Events. Item 8.01 Other Events. On September 17, 2026, Ultragenyx Pharmaceutical Inc. (“Ultragenyx” or the “Company”) announced that the U.S. Food and Drug Administration (the “FDA”) granted standard full approval of FAYUVI™ (rebisufligene etisparvovec-hopf), also known as UX111, for the

Ultragenyx (RARE) received FDA approval for FAYUVI, the first treatment for Sanfilippo syndrome Type A. The gene therapy showed a 23.5-point improvement in cognitive scores. Commercial availability is expected in 30–60 days, with risks including liver enzyme elevations and potential malignancy. The stock rose 2.05% post-announcement.

Ultragenyx Pharmaceutical (RARE) shares rose 10% after the FDA approved Fayuvi, a gene therapy for mucopolysaccharidosis type IIIA. This is the first FDA-authorized treatment for this rare pediatric disease. The therapy showed improved cognitive function in clinical trials but carries risks like liver enzyme increases and potential long-term tumor development.

Ultragenyx Pharmaceutical received FDA approval for Fayuvi, a gene therapy for Sanfilippo syndrome Type A. The treatment targets the enzyme deficiency causing the disease. Ultragenyx shares rose 6% on the news.