Ultragenyx Pharmaceutical Inc.
RARE evidence brief
What we can confirm
What it means
What to watch
Prepared research question
What matters most for RARE—catalysts, financial risk and supporting evidence?
Traceable citations · Unknowns marked
BioSniper AI · RARE
Ultragenyx Pharmaceutical Inc. is a biopharmaceutical company focused on developing and commercializing therapies for rare and ultra-rare diseases, with a portfolio that includes four global commercial products and a pipeline of gene therapy and other candidates.
Key risk: Regulatory setbacks for UX111
BioSniper Score
Based on 6 of 6 signals
Market Cap
$2.52B
Cash Runway
11.7 moLead Asset
Crysvita (Approved)Next Catalyst
Phase2_Start · Oct 1, 2026Financial data as of Jun 30, 2026.
Tracking 8 pipeline candidates · 44 clinical trials · 10 catalysts for Ultragenyx Pharmaceutical Inc..
Ultragenyx Pharmaceutical Inc. is a biopharmaceutical company focused on developing and commercializing therapies for rare and ultra-rare diseases, with a portfolio that includes four global commercial products and a pipeline of gene therapy and other candidates.
- Ultragenyx has four global commercial products generating revenue, with total revenue of $214.0M as of 2026-06-30 [sec].
- The company reported a net loss of $92.0M and shareholders' equity of $151.0M as of 2026-06-30 [sec].
- Ultragenyx received a Complete Response Letter (CRL) for UX111 (Sanfilippo syndrome type A), citing chemistry, manufacturing, and controls issues [sec · filed 2026-03-27].
- Phase 3 studies for UX143 (osteogenesis imperfecta) failed to meet their primary endpoints [sec · filed 2026-03-27].
- The company plans to implement significant expense reductions following operational review [sec · filed 2025-12-29].
What works
- Ultragenyx has four approved commercial products generating revenue, with commercial performance exceeding targets in 2025 (112% achievement) [sec · filed 2026-03-27].
- The company has a broad pipeline including multiple gene therapy and other candidates targeting rare diseases, with several Phase 3 trials ongoing [sec_mda · as of 2026-08-05].
- Ultragenyx has a seasoned executive leadership team with experience in rare disease drug development and commercialization [sec · filed 2025-03-28].
What to weigh
- The company received a Complete Response Letter for UX111, delaying potential FDA approval for Sanfilippo syndrome type A [sec · filed 2026-03-27].
- Phase 3 studies for UX143 in osteogenesis imperfecta failed to meet their primary endpoints, a significant clinical setback [sec · filed 2026-03-27].
- Ultragenyx reported a net loss of $92.0M as of 2026-06-30 and has an accumulated deficit, reflecting ongoing R&D and operational costs [sec].
- Clinical drug development involves lengthy, complex, and expensive processes with uncertain outcomes, and earlier study results may not be predictive [sec_mda · as of 2026-08-05].
From the filings
Quoted directly from source documents.
UX111 received a Complete Response Letter from the FDA due to CMC issues.
“we received a Complete Response Letter (CRL) for UX111 for the treatment of Sanfilippo syndrome type A, with the CRL citing specific chemistry, manufacturing controls related to our facilities and processes”
SEC filings · March 27, 2026
Phase 3 studies for UX143 failed to meet primary endpoints.
“we reported disappointing results for our Phase 3 Orbit and Cosmic studies for UX143 for the treatment of osteogenesis imperfecta when the studies failed to meet their primary endpoi”
SEC filings · March 27, 2026
The company plans to implement expense reductions.
“operations and will promptly define and implement significant expense reductions.”
SEC filings · December 29, 2025
Catalyst timeline
- 2026-10-01 · Phase 2 Start: A Phase 1/2, First-in-human, Double-blind, Placebo-controlled Study to Assess Dose, Safety, and Effi — Initiation of a first-in-human study for an undisclosed candidate, assessing dose, safety, and efficacy.
- 2027-04-01 · Phase 3 Topline: An Open-label, Randomized, Active-Controlled, Phase 3 Study of Setrusumab Compared With Bisphosphona — Topline results from a Phase 3 study of setrusumab in osteogenesis imperfecta, comparing to bisphosphonate.
- 2027-04-01 · Phase 3 Topline: An Operationally Seamless, Randomized Phase 2/3 Study Consisting of a Phase 2 Single-Blind, Dose-Eva — Topline results from a seamless Phase 2/3 study for an undisclosed candidate.
- 2027-08-01 · Phase 3 Topline: A Long-term Follow-up Study of Patients With MPS IIIA From Gene Therapy Clinical Trials Involving th — Long-term follow-up data from gene therapy trials in MPS IIIA (Sanfilippo syndrome type A).
- 2027-08-01 · Phase 3 Topline: A Randomized, Double-blind, Multicenter Study to Determine the Effect of Triheptanoin Compared With — Topline results from a Phase 3 study of triheptanoin for an undisclosed indication.
- 2027-11-01 · Phase 3 Topline: A Phase 3, Randomized, Double-blind, Sham-controlled Study Investigating the Efficacy and Safety of — Topline results from a Phase 3 study of GTX-102 for Angelman syndrome.
- 2028-01-01 · Phase 3 Topline: An Open-label Phase 3 Study of Setrusumab in Pediatric Japanese Subjects With Osteogenesis Imperfect — Topline results from a Phase 3 study of setrusumab in pediatric Japanese patients with osteogenesis imperfecta.
- 2029-02-01 · Phase 3 Topline: A Long-term Extension Trial Investigating the Safety and Efficacy of GTX-102 in Patients With Angelm — Long-term extension data for GTX-102 in Angelman syndrome.
Risks & what to watch (4)›
Key risks
- Regulatory setbacks for UX111 — CRL for UX111 citing CMC issues delays potential approval for Sanfilippo syndrome type A [sec · filed 2026-03-27].
- Clinical trial failures — Phase 3 Orbit and Cosmic studies for UX143 failed to meet primary endpoints [sec · filed 2026-03-27].
- Ongoing net losses — Net loss of $92.0M as of 2026-06-30, with accumulated deficit requiring continued funding [sec].
- Clinical development uncertainty — Drug development is lengthy, complex, and expensive with unpredictable outcomes [sec_mda · as of 2026-08-05].
What to watch
- Resolution of the CRL for UX111 and potential resubmission timeline [sec · filed 2026-03-27].
- Topline data from Phase 3 studies for setrusumab (osteogenesis imperfecta) expected around 2027-04-01 [catalyst_timeline].
- Topline data from Phase 3 study for GTX-102 (Angelman syndrome) expected around 2028-01-01 [catalyst_timeline].
- Implementation and impact of expense reduction plans on cash runway and operations [sec · filed 2025-12-29].
Sources: SEC filings · SEC MD&A · Generated August 29, 2026 · How we verify sources →
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Evidence & data
Score breakdownBased on 6 of 6 signals · derived from public data
11.7 months
OCF -$97M · Net income -$92M
Lead: Approved
8 candidates
10 upcoming, next in ~32d
0 buys · 13 sells (180d)
Runway
Catalysts
Pipeline
Regulatory
Financials
Institutional Holdings
Source: SEC Form 13F · as of Mar 2026Institutional holders
292
Total value held
$1.98B
| Holder | Shares | Value |
|---|---|---|
| vanguard capital management llc | 8,379,662 | $175.6M |
| blackrock, inc. | 7,299,598 | $152.9M |
| vanguard portfolio management llc | 5,385,992 | $112.8M |
| state street corp | 5,021,441 | $105.2M |
| aqr capital management llc | 4,578,024 | $95.9M |
| rtw investments, lp | 3,648,795 | $76.4M |
| sands capital management, llc | 3,214,533 | $67.3M |
| wellington management group llp | 2,640,812 | $55.3M |
| citadel advisors llc | 2,371,391 | $49.7M |
| assenagon asset management s.a. | 2,257,671 | $47.3M |
Showing top 10 of 292 institutional holders of Ultragenyx Pharmaceutical Inc.. Open the full 13F history after sign-in.
Short Interest
as of May 22, 2026- % of float
- 14.4%
- Days to cover
- 7.5
- Shares short
- 13,665,812
- Daily short volume
- -
Short percent of float and days-to-cover reflect reported short positioning. Daily short volume is the exchange-reported short share of a single day's trading volume and is noisier. See the most-shorted biotech ranking →
RARE short interestGovernance
Frequently asked questions
What is the AI investment thesis for Ultragenyx Pharmaceutical Inc.?
Ultragenyx Pharmaceutical Inc. is a biopharmaceutical company focused on developing and commercializing therapies for rare and ultra-rare diseases, with a portfolio that includes four global commercial products and a pipeline of gene therapy and other candidates.
What is Ultragenyx Pharmaceutical Inc.'s lead drug candidate?
Ultragenyx Pharmaceutical Inc.'s most advanced tracked candidate is Crysvita (Approved) for X-Linked Hypophosphatemia (XLH) and Tumor-Induced Osteomalacia (TIO).
What is Ultragenyx Pharmaceutical Inc.'s next catalyst?
Ultragenyx Pharmaceutical Inc.'s next tracked catalyst is a Phase2_Start event — "Phase 2 Start: A Phase 1/2, First-in-human, Double-blind, Placebo-controlled Study to Assess Dose, Safety, and Effi" — expected October 1, 2026.
Who is the CEO of Ultragenyx Pharmaceutical Inc.?
Dr. Emil D. Kakkis M.D., Ph.D. is the chief executive officer of Ultragenyx Pharmaceutical Inc. (RARE).
Where is Ultragenyx Pharmaceutical Inc. headquartered?
Ultragenyx Pharmaceutical Inc. (RARE) is headquartered in Novato, CA, United States.
The AI overview and BioSniper Score are neutral, data-derived signals built from public SEC filings, ClinicalTrials.gov and FDA records — not investment advice.