Mereo BioPharma Shares Plunge After Phase 3 Trial Failures
Written by Emily J. Thompson, Senior Investment Analyst
Updated: Feb 23 2026
0mins
Should l Buy MREO?
Source: Globenewswire
Mereo BioPharma Group PLC's stock price fell by 18.46%, crossing below the 5-day SMA, following a significant announcement regarding its clinical trials.
The decline is attributed to Mereo BioPharma's announcement on December 29, 2025, regarding two Phase 3 studies failing to achieve statistical significance on primary endpoints, leading to a staggering 87.64% drop in stock price. This failure has severely impacted market confidence in its bone metabolism treatment, setrusumab. Additionally, a legal investigation has been initiated, further increasing the company's legal risks and affecting investor sentiment.
The implications of these trial failures are profound, as they not only reflect the challenges faced by Mereo in clinical development but also highlight the market's heightened sensitivity to success rates in biopharmaceutical trials. Investors are likely to remain cautious as the company navigates these setbacks.
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Analyst Views on MREO
Wall Street analysts forecast MREO stock price to rise
8 Analyst Rating
6 Buy
2 Hold
0 Sell
Strong Buy
Current: 0.337
Low
0.50
Averages
2.08
High
5.00
Current: 0.337
Low
0.50
Averages
2.08
High
5.00
About MREO
Mereo BioPharma Group plc is a biopharmaceutical company focused on the development of therapeutics for rare diseases. The Company has developed a portfolio of late-stage clinical product candidates, and its two rare disease product candidates are setrusumab for the treatment of osteogenesis imperfecta (OI) and alvelestat primarily for the treatment of severe alpha-1 antitrypsin deficiency-associated lung disease (AATD-LD). In addition to the rare disease programs, it has two oncology product candidates in clinical development, which include Etigilimab, an IgG1 monoclonal antibody which binds to the human T-cell immunoreceptor with Ig and ITIM domains (TIGIT) receptor on immune cells to improve the activation and effectiveness of T-cell and NK cell antitumor activity and Navicixizumab is a bispecific antibody that inhibits delta-like ligand 4 (DLL4) and vascular endothelial growth factor (VEGF). Navicixizumab is developed for the treatment of late-line ovarian cancer.
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.
Mereo BioPharma Class Action Notice Issued
- Class Action Deadline: Rosen Law Firm reminds investors who purchased Mereo BioPharma ADS between June 5, 2023, and December 26, 2025, that they must apply to be lead plaintiff by April 6, 2026, to represent other members in the class action.
- Lawsuit Background: The lawsuit alleges that defendants provided false and misleading information regarding the Phase 3 Orbit and COSMIC studies, leading investors to purchase Mereo's ADS at artificially inflated prices, resulting in financial losses when the truth emerged.
- Law Firm Credentials: 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 in this area.
- Investor Guidance: Investors are advised to select counsel with a proven leadership record to ensure effective legal support in the class action, avoiding firms that merely act as intermediaries without substantial litigation experience.
See More
Class Action Lawsuit Filed Against Mereo BioPharma Group
- Lawsuit Background: Bragar Eagel & Squire has filed a class action lawsuit against Mereo BioPharma Group in the Southern District of New York on behalf of investors who purchased American Depositary Shares between June 5, 2023, and December 26, 2025.
- False Information Allegations: The lawsuit alleges that Mereo provided misleading information regarding the expected results of its Phase 3 ORBIT and COSMIC studies for setrusumab, leading investors to buy shares at artificially inflated prices without knowing the true situation.
- Stock Price Plummet: On December 29, 2025, Mereo announced that its studies failed to meet primary endpoints, causing its stock price to plummet from $2.31 per share on December 26, 2025, to $0.29 per share, representing a decline of over 87.7%, resulting in significant losses for investors.
- Investor Rights Protection: Affected investors are encouraged to contact the law firm to discuss their legal rights, indicating that this lawsuit may provide an opportunity for investors to recover losses, highlighting the need for transparency and accurate information disclosure from the company.
See More
Mereo BioPharma Faces Class Action Lawsuit Reminder
- Class Action Reminder: The Schall Law Firm reminds investors of a class action lawsuit against Mereo BioPharma Group plc for violations of §§10(b) and 20(a) of the Securities Exchange Act, concerning securities purchased between June 5, 2023, and December 26, 2025.
- False Statements Exposed: The complaint alleges that Mereo concealed negative facts regarding its Phase 3 ORBIT and COSMIC programs, rendering its public statements false and materially misleading throughout the class period.
- Investor Losses: As the market learned the truth about Mereo's failure to meet primary endpoints, investors suffered damages, indicating a significant impact on the company's stock price and investor confidence.
- Legal Consultation Opportunity: The Schall Law Firm encourages affected shareholders to contact them before April 6, 2026, to participate in the lawsuit and discuss their rights, offering free legal consultations.
See More
Reminder of Class Action for Mereo BioPharma ADS Purchasers
- Class Action Notice: Rosen Law Firm reminds investors who purchased Mereo BioPharma ADS between June 5, 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 the Phase 3 Orbit and COSMIC studies, leading investors to purchase Mereo's ADS at artificially inflated prices, resulting in investor losses when the truth emerged.
- Law Firm's Advantage: Rosen Law Firm specializes in securities class actions and has recovered over $438 million for investors in 2019 alone, demonstrating its successful track record and extensive experience in this field.
- Investor Selection Advice: Investors are advised to carefully choose law firms with proven success in leadership roles to ensure optimal representation in the class action, avoiding those that merely act as intermediaries.
See More
Class Action Filed Against Mereo BioPharma Group plc for Securities Violations
- Class Action Initiation: Bronstein, Gewirtz & Grossman, LLC has announced a class action lawsuit against Mereo BioPharma Group plc, aiming to recover damages for investors who purchased securities between June 5, 2023, and December 26, 2025, reflecting significant investor concern over the company's financial transparency.
- Allegations of Misrepresentation: The complaint alleges that Mereo provided overly optimistic statements to investors while concealing critical adverse facts regarding its Phase 3 ORBIT and COSMIC programs, leading to investor misconceptions about the company's prospects, which could negatively impact stock prices.
- Investor Action Deadline: Affected investors must request to be appointed as lead plaintiff by April 6, 2026, to share in any potential recovery, highlighting the urgency for investors to engage in the legal process to protect their interests.
- No-Cost Legal Representation: Bronstein, Gewirtz & Grossman, LLC offers contingency-based legal services, charging fees only upon successful recovery, which reduces the financial burden on investors and encourages more victims to seek legal recourse.
See More
Class Action Notice for Mereo BioPharma Investors
- Class Action Deadline: Investors in Mereo BioPharma Group plc must apply to be lead plaintiffs in the class action by April 6, 2026, to potentially receive compensation without any out-of-pocket costs, highlighting the urgency of the legal process and the potential benefits for investors.
- False Statements Allegations: The lawsuit alleges that defendants provided misleading positive expectations regarding setrusumab's performance in the Phase 3 Orbit and COSMIC studies, leading investors to purchase ADS at artificially inflated prices, reflecting serious deficiencies in the company's disclosure practices.
- Law Firm Background: The Rosen Law Firm specializes in securities class actions and has recovered over $438 million for investors in 2019 alone, demonstrating its extensive experience and successful track record in handling such cases, which enhances investor confidence in their representation.
- Investor Action Recommendations: Investors can obtain more information by visiting the Rosen Law Firm's website or calling their toll-free number, emphasizing the importance of selecting qualified counsel to ensure effective protection of their rights in legal matters.
See More
Mereo BioPharma Class Action Notice Issued
- Class Action Deadline: Rosen Law Firm reminds investors who purchased Mereo BioPharma ADS between June 5, 2023, and December 26, 2025, that they must apply to be lead plaintiff by April 6, 2026, to represent other members in the class action.
- Lawsuit Background: The lawsuit alleges that defendants provided false and misleading information regarding the Phase 3 Orbit and COSMIC studies, leading investors to purchase Mereo's ADS at artificially inflated prices, resulting in financial losses when the truth emerged.
- Law Firm Credentials: 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 in this area.
- Investor Guidance: Investors are advised to select counsel with a proven leadership record to ensure effective legal support in the class action, avoiding firms that merely act as intermediaries without substantial litigation experience.
See More
Class Action Lawsuit Filed Against Mereo BioPharma Group
- Lawsuit Background: Bragar Eagel & Squire has filed a class action lawsuit against Mereo BioPharma Group in the Southern District of New York on behalf of investors who purchased American Depositary Shares between June 5, 2023, and December 26, 2025.
- False Information Allegations: The lawsuit alleges that Mereo provided misleading information regarding the expected results of its Phase 3 ORBIT and COSMIC studies for setrusumab, leading investors to buy shares at artificially inflated prices without knowing the true situation.
- Stock Price Plummet: On December 29, 2025, Mereo announced that its studies failed to meet primary endpoints, causing its stock price to plummet from $2.31 per share on December 26, 2025, to $0.29 per share, representing a decline of over 87.7%, resulting in significant losses for investors.
- Investor Rights Protection: Affected investors are encouraged to contact the law firm to discuss their legal rights, indicating that this lawsuit may provide an opportunity for investors to recover losses, highlighting the need for transparency and accurate information disclosure from the company.
See More
Mereo BioPharma Faces Class Action Lawsuit Reminder
- Class Action Reminder: The Schall Law Firm reminds investors of a class action lawsuit against Mereo BioPharma Group plc for violations of §§10(b) and 20(a) of the Securities Exchange Act, concerning securities purchased between June 5, 2023, and December 26, 2025.
- False Statements Exposed: The complaint alleges that Mereo concealed negative facts regarding its Phase 3 ORBIT and COSMIC programs, rendering its public statements false and materially misleading throughout the class period.
- Investor Losses: As the market learned the truth about Mereo's failure to meet primary endpoints, investors suffered damages, indicating a significant impact on the company's stock price and investor confidence.
- Legal Consultation Opportunity: The Schall Law Firm encourages affected shareholders to contact them before April 6, 2026, to participate in the lawsuit and discuss their rights, offering free legal consultations.
See More
Reminder of Class Action for Mereo BioPharma ADS Purchasers
- Class Action Notice: Rosen Law Firm reminds investors who purchased Mereo BioPharma ADS between June 5, 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 the Phase 3 Orbit and COSMIC studies, leading investors to purchase Mereo's ADS at artificially inflated prices, resulting in investor losses when the truth emerged.
- Law Firm's Advantage: Rosen Law Firm specializes in securities class actions and has recovered over $438 million for investors in 2019 alone, demonstrating its successful track record and extensive experience in this field.
- Investor Selection Advice: Investors are advised to carefully choose law firms with proven success in leadership roles to ensure optimal representation in the class action, avoiding those that merely act as intermediaries.
See More
Class Action Filed Against Mereo BioPharma Group plc for Securities Violations
- Class Action Initiation: Bronstein, Gewirtz & Grossman, LLC has announced a class action lawsuit against Mereo BioPharma Group plc, aiming to recover damages for investors who purchased securities between June 5, 2023, and December 26, 2025, reflecting significant investor concern over the company's financial transparency.
- Allegations of Misrepresentation: The complaint alleges that Mereo provided overly optimistic statements to investors while concealing critical adverse facts regarding its Phase 3 ORBIT and COSMIC programs, leading to investor misconceptions about the company's prospects, which could negatively impact stock prices.
- Investor Action Deadline: Affected investors must request to be appointed as lead plaintiff by April 6, 2026, to share in any potential recovery, highlighting the urgency for investors to engage in the legal process to protect their interests.
- No-Cost Legal Representation: Bronstein, Gewirtz & Grossman, LLC offers contingency-based legal services, charging fees only upon successful recovery, which reduces the financial burden on investors and encourages more victims to seek legal recourse.
See More
Class Action Notice for Mereo BioPharma Investors
- Class Action Deadline: Investors in Mereo BioPharma Group plc must apply to be lead plaintiffs in the class action by April 6, 2026, to potentially receive compensation without any out-of-pocket costs, highlighting the urgency of the legal process and the potential benefits for investors.
- False Statements Allegations: The lawsuit alleges that defendants provided misleading positive expectations regarding setrusumab's performance in the Phase 3 Orbit and COSMIC studies, leading investors to purchase ADS at artificially inflated prices, reflecting serious deficiencies in the company's disclosure practices.
- Law Firm Background: The Rosen Law Firm specializes in securities class actions and has recovered over $438 million for investors in 2019 alone, demonstrating its extensive experience and successful track record in handling such cases, which enhances investor confidence in their representation.
- Investor Action Recommendations: Investors can obtain more information by visiting the Rosen Law Firm's website or calling their toll-free number, emphasizing the importance of selecting qualified counsel to ensure effective protection of their rights in legal matters.
See More
