Mereo BioPharma Group plc Annual Report - How They Did This Year

Hey there! Think of this as our chat about Mereo BioPharma's year. We'll explain what they're doing, their money situation, and the big things that happened. This plain English guide helps you decide if you want to put your hard-earned cash into them.

This report covers their financial year that ended on December 31, 2025.

Who is Mereo BioPharma and What Do They Do?

Mereo BioPharma Group plc is a biopharmaceutical company based in England and Wales. Their shares are traded on the Nasdaq Stock Market in the US under the ticker MREO.

They develop new medicines, mainly for rare diseases and cancer. Think of their main projects (or "drug candidates") as follows:

• Setrusumab (for OI): This special antibody treats Osteogenesis Imperfecta (OI). It's also called "brittle bone disease." It's a rare genetic disorder where bones break easily. Setrusumab is Mereo's main drug in development. They are developing it with Ultragenyx Pharmaceutical Inc. It's in advanced clinical trials (Phase 2/3 study). This makes it a key driver for the company's value.
• Alvelestat (for AATD): This drug treats Alpha-1 Antitrypsin Deficiency (AATD). This condition damages lungs due to a protein shortage. Alvelestat is in Phase 2 clinical development.
• Etigilimab (for Cancer): This anti-TIGIT drug boosts the immune system. It helps the body fight tumors. Etigilimab is in Phase 1b/2 clinical development. It was previously developed with OncXerna Therapeutics.
• Navicixizumab (for Ovarian Cancer): This antibody treats advanced ovarian cancer. It's for cases where other treatments failed. Navicixizumab is in Phase 1b clinical development. They licensed it from OncXerna Therapeutics.
• Leflutrozole (for Male Infertility): This oral treatment helps male infertility. It targets hormone imbalances (HH). Leflutrozole is in Phase 2 clinical development.
• Acumapimod (for COPD): This drug helps sudden worsening of COPD. COPD is a lung condition causing breathing issues. Acumapimod is in Phase 2 clinical development.
• Vantictumab (for ADO2): This antibody treats ADO2, a rare bone disorder. ADO2 stands for Autosomal Dominant Osteopetrosis Type 2. Vantictumab is in Phase 1b/2 clinical development.

Company Size and Status

As of June 30, 2025, their publicly traded shares were worth about $368.5 million. They had about 798 million ordinary shares issued as of March 18, 2026. Based on these figures, each share was worth about $0.46 then.

Regulators call the company a "Smaller reporting company" and a "Non-accelerated filer." This means they are a smaller public company. Their reporting rules differ from larger companies. Investors usually see less detailed information. This can mean less transparency than larger companies. They are not a "well-known seasoned issuer." This also shows their current size and market presence. It often means less trading and more price swings.