Ultragenyx and Mereo Face Class Action Lawsuits
Written by Emily J. Thompson, Senior Investment Analyst
Updated: 1 hour ago
0mins
Should l Buy RARE?
Source: Globenewswire
- Lawsuit Background: Bragar Eagel & Squire, P.C. has alerted investors that Ultragenyx Pharmaceutical Inc. and Mereo BioPharma Group plc are facing class action lawsuits, with a deadline of April 6, 2026, for investors to apply as lead plaintiffs, indicating significant investor concern over potential risks associated with these companies.
- Ultragenyx Lawsuit Details: On December 29, 2025, Ultragenyx announced that its Phase III Orbit and Cosmic studies failed to achieve statistical significance in reducing fracture rates, causing its stock price to plummet from $34.19 to $19.72, a decline of 42.32%, reflecting market disappointment in the study results.
- Mereo Lawsuit Details: Mereo BioPharma faces similar allegations as its Phase 3 ORBIT and COSMIC studies did not meet the primary endpoint of reducing annualized fracture rates, leading to a drastic drop in its stock price from $2.31 to $0.29, a decline of over 87.7%, showcasing extreme investor pessimism regarding its prospects.
- Investor Impact: Both companies are accused of failing to disclose research risks adequately, resulting in shareholders purchasing stocks at inflated prices; the initiation of class action lawsuits may severely impact their future financing and market confidence, exacerbating investor anxiety.
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Analyst Views on RARE
Wall Street analysts forecast RARE stock price to rise
18 Analyst Rating
17 Buy
1 Hold
0 Sell
Strong Buy
Current: 20.520
Low
35.00
Averages
61.65
High
120.00
Current: 20.520
Low
35.00
Averages
61.65
High
120.00
About RARE
Ultragenyx Pharmaceutical Inc. is a biopharmaceutical company. The Company is focused on the identification, acquisition, development, and commercialization of novel products for the treatment of serious rare and ultrarare genetic diseases. Its therapies and clinical-stage pipeline consist of four product categories: biologics, small molecules, AAV gene therapy, and nucleic acid product candidates. Its four approved product candidates include Crysvita (burosumab) for the treatment of X-linked hypophosphatemia (XLH), and tumor-induced osteomalacia (TIO), Mepsevii (vestronidase alfa) for the treatment of mucopolysaccharidosis VII (MPSVII) or Sly Syndrome, Dojolvi (triheptanoin) for the treatment of long-chain fatty acid oxidation disorders (LC-FAOD), and Evkeeza (evinacumab) for the treatment of homozygous familial hypercholesterolemia (HoFH). Its clinical product candidates include DTX401, DTX301, UX701, UX143, UX111, and GTX-102. UX143 for the treatment of Osteogenesis Imperfecta.
About the author
Emily J. Thompson
Emily J. Thompson, a Chartered Financial Analyst (CFA) with 12 years in investment research, graduated with honors from the Wharton School. Specializing in industrial and technology stocks, she provides in-depth analysis for Intellectia’s earnings and market brief reports.
Ultragenyx and Mereo Face Class Action Lawsuits
- Lawsuit Background: Bragar Eagel & Squire, P.C. has alerted investors that Ultragenyx Pharmaceutical Inc. and Mereo BioPharma Group plc are facing class action lawsuits, with a deadline of April 6, 2026, for investors to apply as lead plaintiffs, indicating significant investor concern over potential risks associated with these companies.
- Ultragenyx Lawsuit Details: On December 29, 2025, Ultragenyx announced that its Phase III Orbit and Cosmic studies failed to achieve statistical significance in reducing fracture rates, causing its stock price to plummet from $34.19 to $19.72, a decline of 42.32%, reflecting market disappointment in the study results.
- Mereo Lawsuit Details: Mereo BioPharma faces similar allegations as its Phase 3 ORBIT and COSMIC studies did not meet the primary endpoint of reducing annualized fracture rates, leading to a drastic drop in its stock price from $2.31 to $0.29, a decline of over 87.7%, showcasing extreme investor pessimism regarding its prospects.
- Investor Impact: Both companies are accused of failing to disclose research risks adequately, resulting in shareholders purchasing stocks at inflated prices; the initiation of class action lawsuits may severely impact their future financing and market confidence, exacerbating investor anxiety.
See More
Ultragenyx Pharmaceutical Faces Class Action Lawsuit
- Lawsuit Background: Kahn Swick & Foti LLC has notified investors in Ultragenyx Pharmaceutical of a class action lawsuit due to alleged securities fraud occurring between August 3, 2023, and December 26, 2025, aimed at recovering losses for affected investors.
- Stock Price Plunge: Following the announcement on December 26, 2025, that setrusumab (UX143) failed to show a statistically significant reduction in annualized fracture rates in its Phase III studies, Ultragenyx's stock price plummeted approximately 42%, from $34.19 to $19.72 by December 29, 2025.
- Legal Deadline: Investors have until April 6, 2026, to request to be appointed as lead plaintiff, although serving in this capacity is not a prerequisite for sharing in any recovery, which may influence investors' decisions regarding claims.
- Law Firm Overview: Kahn Swick & Foti is recognized as one of the nation's premier boutique securities litigation firms, ranked among the top 10 nationally based on total settlement value, focusing on providing legal support to investors suffering losses due to corporate fraud.
See More
Class Action Lawsuit Reminder Against Ultragenyx Pharmaceutical Inc.
- Class Action Notice: The Schall Law Firm reminds investors of a class action lawsuit against Ultragenyx Pharmaceutical Inc. for violations of securities laws, concerning securities transactions from August 3, 2023, to December 26, 2025, with a deadline for participation by April 6, 2026.
- False Statements Exposed: The complaint alleges that Ultragenyx made false and misleading statements regarding its drug candidate's effects on Osteogenesis Imperfecta patients, leading to an overly optimistic market perception and undermining investor confidence in the company's stock.
- Clinical Trial Failure: The Phase III ORBIT study revealed that Ultragenyx failed to achieve a statistically significant reduction in annualized fracture rate, highlighting significant errors in the company's drug efficacy claims and exacerbating investor losses.
- Opportunity for Loss Recovery: Investors are encouraged to join the lawsuit to recover losses, as the Schall Law Firm specializes in securities class actions and offers free consultations to assist affected shareholders in asserting their rights.
See More
Ultragenyx Pharmaceutical Class Action Lawsuit Update
- Lawsuit Timeline: Purchasers of Ultragenyx Pharmaceutical stock between August 3, 2023, and December 26, 2025, must apply by April 6, 2026, to be appointed lead plaintiff in the class action lawsuit, indicating investor concern over potential legal risks facing the company.
- Allegations Overview: The lawsuit accuses Ultragenyx and its executives of violating the Securities Exchange Act of 1934, claiming misleading statements regarding drug efficacy in clinical trials, which may have led to significant investor losses, highlighting deficiencies in the company's transparency and compliance.
- Stock Price Impact: Following the announcement on July 9, 2025, that the clinical trial failed to achieve statistical significance, Ultragenyx's stock plummeted over 25%; a subsequent announcement on December 29, 2025, regarding further trial failures resulted in an additional 42% drop, reflecting extreme market pessimism about the company's future.
- Legal Process Explanation: Under the Private Securities Litigation Reform Act of 1995, any investor who purchased Ultragenyx stock during the class period can seek to be appointed lead plaintiff, who will represent other investors in the lawsuit, emphasizing the critical role of investors in legal actions.
See More
Ultragenyx Pharmaceutical Class Action Notice Issued
- Class Action Notice: Rosen Law Firm reminds investors who purchased Ultragenyx (NASDAQ:RARE) common stock between August 3, 2023, and December 26, 2025, to apply as lead plaintiffs by April 6, 2026, to participate in the class action and seek compensation.
- Lawsuit Background: The lawsuit alleges that defendants provided false and misleading information regarding setrusumab (UX 143) during Phase III Orbit and Cosmic studies, leading investors to purchase shares at artificially inflated prices.
- Potential Losses: The lawsuit claims that while setrusumab increases bone density, it does not correlate with a decrease in annualized fracture rates, resulting in investor losses when the true facts emerged, highlighting significant deficiencies in the company's disclosures.
- Law Firm's Advantage: Rosen Law Firm specializes in securities class actions and has recovered over $438 million for investors in 2019 alone, demonstrating a strong track record and extensive experience, urging investors to be cautious in selecting legal counsel.
See More
Ultragenyx Pharmaceutical Faces Securities Fraud Class Action Lawsuit
- Lawsuit Background: Ultragenyx Pharmaceutical Inc. (NASDAQ: RARE) is facing a securities fraud class action lawsuit for actions taken between August 3, 2023, and December 26, 2025, with investors having until April 6, 2026, to seek lead plaintiff status, indicating significant legal risks for the company.
- Allegation Details: The lawsuit alleges that the company misled investors by failing to disclose risks associated with its drug setrusumab, particularly regarding the Phase III Orbit study's potential failure to achieve a statistically significant reduction in annualized fracture rate, which could negatively impact stock prices.
- Investor Action: Affected investors are encouraged to contact Kessler Topaz Meltzer & Check, LLP for a free case evaluation, highlighting the potential financial liabilities and reputational damage the company may face due to these allegations.
- Legal Process: Investors can apply to be lead plaintiffs by April 6, 2026, or choose to remain absent class members, illustrating the complexities and potential impacts of legal proceedings on investor rights and company operations.
See More
Ultragenyx and Mereo Face Class Action Lawsuits
- Lawsuit Background: Bragar Eagel & Squire, P.C. has alerted investors that Ultragenyx Pharmaceutical Inc. and Mereo BioPharma Group plc are facing class action lawsuits, with a deadline of April 6, 2026, for investors to apply as lead plaintiffs, indicating significant investor concern over potential risks associated with these companies.
- Ultragenyx Lawsuit Details: On December 29, 2025, Ultragenyx announced that its Phase III Orbit and Cosmic studies failed to achieve statistical significance in reducing fracture rates, causing its stock price to plummet from $34.19 to $19.72, a decline of 42.32%, reflecting market disappointment in the study results.
- Mereo Lawsuit Details: Mereo BioPharma faces similar allegations as its Phase 3 ORBIT and COSMIC studies did not meet the primary endpoint of reducing annualized fracture rates, leading to a drastic drop in its stock price from $2.31 to $0.29, a decline of over 87.7%, showcasing extreme investor pessimism regarding its prospects.
- Investor Impact: Both companies are accused of failing to disclose research risks adequately, resulting in shareholders purchasing stocks at inflated prices; the initiation of class action lawsuits may severely impact their future financing and market confidence, exacerbating investor anxiety.
See More
Ultragenyx Pharmaceutical Faces Class Action Lawsuit
- Lawsuit Background: Kahn Swick & Foti LLC has notified investors in Ultragenyx Pharmaceutical of a class action lawsuit due to alleged securities fraud occurring between August 3, 2023, and December 26, 2025, aimed at recovering losses for affected investors.
- Stock Price Plunge: Following the announcement on December 26, 2025, that setrusumab (UX143) failed to show a statistically significant reduction in annualized fracture rates in its Phase III studies, Ultragenyx's stock price plummeted approximately 42%, from $34.19 to $19.72 by December 29, 2025.
- Legal Deadline: Investors have until April 6, 2026, to request to be appointed as lead plaintiff, although serving in this capacity is not a prerequisite for sharing in any recovery, which may influence investors' decisions regarding claims.
- Law Firm Overview: Kahn Swick & Foti is recognized as one of the nation's premier boutique securities litigation firms, ranked among the top 10 nationally based on total settlement value, focusing on providing legal support to investors suffering losses due to corporate fraud.
See More
Class Action Lawsuit Reminder Against Ultragenyx Pharmaceutical Inc.
- Class Action Notice: The Schall Law Firm reminds investors of a class action lawsuit against Ultragenyx Pharmaceutical Inc. for violations of securities laws, concerning securities transactions from August 3, 2023, to December 26, 2025, with a deadline for participation by April 6, 2026.
- False Statements Exposed: The complaint alleges that Ultragenyx made false and misleading statements regarding its drug candidate's effects on Osteogenesis Imperfecta patients, leading to an overly optimistic market perception and undermining investor confidence in the company's stock.
- Clinical Trial Failure: The Phase III ORBIT study revealed that Ultragenyx failed to achieve a statistically significant reduction in annualized fracture rate, highlighting significant errors in the company's drug efficacy claims and exacerbating investor losses.
- Opportunity for Loss Recovery: Investors are encouraged to join the lawsuit to recover losses, as the Schall Law Firm specializes in securities class actions and offers free consultations to assist affected shareholders in asserting their rights.
See More
Ultragenyx Pharmaceutical Class Action Lawsuit Update
- Lawsuit Timeline: Purchasers of Ultragenyx Pharmaceutical stock between August 3, 2023, and December 26, 2025, must apply by April 6, 2026, to be appointed lead plaintiff in the class action lawsuit, indicating investor concern over potential legal risks facing the company.
- Allegations Overview: The lawsuit accuses Ultragenyx and its executives of violating the Securities Exchange Act of 1934, claiming misleading statements regarding drug efficacy in clinical trials, which may have led to significant investor losses, highlighting deficiencies in the company's transparency and compliance.
- Stock Price Impact: Following the announcement on July 9, 2025, that the clinical trial failed to achieve statistical significance, Ultragenyx's stock plummeted over 25%; a subsequent announcement on December 29, 2025, regarding further trial failures resulted in an additional 42% drop, reflecting extreme market pessimism about the company's future.
- Legal Process Explanation: Under the Private Securities Litigation Reform Act of 1995, any investor who purchased Ultragenyx stock during the class period can seek to be appointed lead plaintiff, who will represent other investors in the lawsuit, emphasizing the critical role of investors in legal actions.
See More
Ultragenyx Pharmaceutical Class Action Notice Issued
- Class Action Notice: Rosen Law Firm reminds investors who purchased Ultragenyx (NASDAQ:RARE) common stock between August 3, 2023, and December 26, 2025, to apply as lead plaintiffs by April 6, 2026, to participate in the class action and seek compensation.
- Lawsuit Background: The lawsuit alleges that defendants provided false and misleading information regarding setrusumab (UX 143) during Phase III Orbit and Cosmic studies, leading investors to purchase shares at artificially inflated prices.
- Potential Losses: The lawsuit claims that while setrusumab increases bone density, it does not correlate with a decrease in annualized fracture rates, resulting in investor losses when the true facts emerged, highlighting significant deficiencies in the company's disclosures.
- Law Firm's Advantage: Rosen Law Firm specializes in securities class actions and has recovered over $438 million for investors in 2019 alone, demonstrating a strong track record and extensive experience, urging investors to be cautious in selecting legal counsel.
See More
Ultragenyx Pharmaceutical Faces Securities Fraud Class Action Lawsuit
- Lawsuit Background: Ultragenyx Pharmaceutical Inc. (NASDAQ: RARE) is facing a securities fraud class action lawsuit for actions taken between August 3, 2023, and December 26, 2025, with investors having until April 6, 2026, to seek lead plaintiff status, indicating significant legal risks for the company.
- Allegation Details: The lawsuit alleges that the company misled investors by failing to disclose risks associated with its drug setrusumab, particularly regarding the Phase III Orbit study's potential failure to achieve a statistically significant reduction in annualized fracture rate, which could negatively impact stock prices.
- Investor Action: Affected investors are encouraged to contact Kessler Topaz Meltzer & Check, LLP for a free case evaluation, highlighting the potential financial liabilities and reputational damage the company may face due to these allegations.
- Legal Process: Investors can apply to be lead plaintiffs by April 6, 2026, or choose to remain absent class members, illustrating the complexities and potential impacts of legal proceedings on investor rights and company operations.
See More
