Ultragenyx Pharmaceutical Inc. (NASDAQ:RARE), based in Novato, California, focuses on developing therapies for rare and ultra-rare genetic diseases and tops our list for being one of the best growth stocks. The company’s portfolio includes commercial products and a strong late-stage pipeline targeting high-need conditions such as Sanfilippo syndrome type A, osteogenesis imperfecta, Angelman syndrome, and glycogen storage diseases.\n\nA key recent development was the FDA’s Complete Response Letter (CRL) on July 11, 2025, for the company’s Biologics License Application for UX111, a gene therapy for Sanfilippo syndrome type A. While the FDA highlighted chemistry, manufacturing, and controls (CMC) issues, it also recognized the robust clinical and biomarker data, affirming the therapy’s efficacy. The business intends to resolve the CMC concerns and resubmit the application, expecting a six-month review.\n\nBeyond UX111, Ultragenyx Pharmaceutical Inc. (NASDAQ:RARE) is advancing other promising therapies. UX143, targeting osteogenesis imperfecta, is progressing toward final analysis after a Phase 3 study. GTX-102, for Angelman syndrome, recently received the FDA Breakthrough Therapy designation, indicating its potential for accelerated development.\n\nThe corporation’s strategy is notable for its modality-agnostic approach, leveraging gene therapies, monoclonal antibodies, and antisense oligonucleotides. This diversified platform reduces regulatory risk while maximizing impact across several rare disorders.\n\nAdding to its momentum, Ultragenyx Pharmaceutical Inc. (NASDAQ:RARE) recently gained Health Canada approval to expand the use of Evkeeza to infants as young as six months with homozygous familial hypercholesterolemia (HoFH), enhancing its commercial reach.

Ultragenyx Pharmaceutical Inc. (RARE) Gets FDA CRL for UX111, Vows Quick Resubmission

Ultragenyx Pharmaceutical Inc. (NASDAQ:RARE) received a FDA Complete Response Letter (CRL) for its Biologics License Application for UX111, a gene therapy for Sanfilippo syndrome type A. The company plans to resolve chemistry, manufacturing, and controls (CMC) issues and resubmit the application within six months. It is also advancing UX143 for osteogenesis imperfecta and GTX-102 for Angelman syndrome, with the latter receiving FDA Breakthrough Therapy designation. The company expanded Evkeeza’s use to infants with homozygous familial hypercholesterolemia (HoFH) after Health Canada approval.