Mironid lands $46M Series B to take kidney drug into clinic
Scottish biotech Mironid has raised $46 million (€40 million) in a Series B financing to advance MR-L45, its small-molecule candidate for autosomal dominant polycystic kidney disease (ADPKD) through clinical development.
Why it matters: Mironid is moving into human testing as several rival ADPKD programmes reach Phase 2 or prepare for pivotal development. The company will need to show that its approach can improve on tolvaptan, the only drug approved to slow the disease.
Zoom in: The Scottish National Investment Bank joined existing investors Roche Venture Fund, Epidarex Capital, Sofinnova Partners, BioGeneration Ventures and the University of Strathclyde in the round.
- A Mironid spokesperson told European Biotechnology that the financing “will support the advancement of MR-L45 through clinical development, which remains our clear priority.”
- Mironid’s previous financing, a 2023 Series A extension, brought its total funding at the time to £35 million (€41 million).
How it works: Mironid’s orally available LoAc molecules, MR-L45, activate long-form PDE4 enzymes, increasing the breakdown of cAMP. Abnormally high cAMP levels promote cell growth and fluid secretion into the cysts that progressively damage the kidneys in ADPKD.
- Mironid describes LoAc as the only therapeutic approach that directly targets the abnormal cAMP signalling involved in both the initiation and continued growth of kidney cysts. The company believes the mechanism could benefit patients across the course of ADPKD, including those unable to tolerate existing treatments.
- Tolvaptan, sold by Otsuka Pharmaceutical as Jinarc in Europe, reduces cAMP indirectly by blocking the vasopressin V2 receptor. It can slow disease progression but commonly causes thirst and increased urination and requires liver monitoring.
Between the lines: The EU clinical trial registry lists MR-L45 in a first-in-human Phase 1 study sponsored by Mironid. The trial is recruiting 72 healthy adults at one site in Groningen, the Netherlands, and is assessing safety, tolerability and pharmacokinetics. The spokesperson did not disclose the trial’s current recruitment status, dosing design, expected completion date or timing of the first clinical data.
What is known: A Mironid spokesperson told European Biotechnology that LoAc reduced cyst numbers and kidney volume in preclinical models, alongside what the company described as encouraging safety findings. Mironid has not publicly provided the underlying numerical data or specified whether those results were generated with MR-L45.
- The most detailed public efficacy data concern MR-L22, a different LoAc compound. In a 2024 European Renal Association abstract, an oral dose of MR-L22 lowered urinary cyclic AMP, or cAMP, by more than 40% in rats.
- MR-L22 also reduced kidney volume, cyst burden and disease markers in an ADPKD mouse model. The researchers reported fewer effects on urine production than with tolvaptan, although they could not establish whether combining the two treatments provided an additional benefit.
The big picture: Mironid is entering behind three differently positioned programmes:
- Farabursen: Novartis acquired Regulus Therapeutics for up to $1.7 billion to obtain the injectable miR-17 inhibitor. It has completed Phase 1b testing in ADPKD patients, and Novartis presented the design of a global Phase 3 trial in May.
- ABBV-CLS-628: Calico’s anti-PAPP-A antibody is being administered intravenously every four weeks in a randomized Phase 2 trial.
- VX-407: Vertex Pharmaceuticals’ oral corrector is in Phase 2 but targets only certain PKD1 variants, representing up to about 10% of the ADPKD population.
What to watch: Mironid could potentially differentiate through oral dosing, broad genetic applicability and fewer side effects than tolvaptan. Mironid is currently developing MR-L45 as a standalone treatment rather than as a combination with tolvaptan. A spokesperson said the company’s focus is on establishing MR-L45 as “a differentiated treatment option in its own right.” For now, those advantages remain preclinical hypotheses, while its competitors are already generating data in people with ADPKD.
Editor’s note: this article has been updated on August 6, 2026 at 11:30 CEST to include comments from Mironid.
