Tolvaptan

Mironid has secured $46m in a Series B funding round backed by Roche and Sofinnova Partners. Credit: mi_viri / Shutterstock.com. Scottish biopharmaceutical company Mironid has pocketed $46m in Series B funding raise to progress the development of its lead rare kidney disease candidate. The financing, which was contributed to by Roche Venture Fund and Sofinnova Partners, as well as the Scottish National Investment Bank, Epidarex Capital and BioGeneration Ventures, will help Mironid progress its lead small molecule autosomal dominant polycystic kidney disease (ADPKD) closer to the clinic. Following the extension of its Series A raise in 2023, Mironid’s CEO, Neil Wilkie, tells Pharmaceutical Technology that the company has delivered on the objectives of the raise by completing investigational new drug (IND)-enabling studies and expanding its patent portfolio. Now, with new capital in hand, Wilkie says that the company should be set cash-wise through to the generation of initial clinical data. Mironid progresses its pipeline as ADPKD impacts around 12.4 million individuals worldwide – making it the most common inherited kidney disorder , despite its status as a rare disease. The condition, which is primarily caused by mutations in the PDK1 or PDK2 genes, is characterised by the uncontrolled growth of fluid-filled cysts on the kidney, leading to kidney failure in as many as half of those suffering from the disease by the age of 60. Treating ADPKD: the challenges and opportunities Currently, the only available targeted treatment option for ADPKD is Otsuka Pharmaceutical’s Jynarque (tolvaptan), which secured approval for use in the condition back in 2018. However, there are several side effects associated with the drug, including excessive thirst, frequent urination and potential severe liver damage – meaning some patients may choose to discontinue treatment. Unlike Jynarque, which acts as a selective vasopressin V₂ receptor antagonist, Mironid’s lead candidate targets cyclic AMP (cAMP), a secondary messenger molecule that plays a key role in regulating physiological processes in the body. When cAMP is activated at abnormally high levels, it can also play a significant role in all stages of ADPKD, Wilkie says. By designing a small molecule that can activate the degradation of cAMP through the activation of long-form PDE4 enzymes, Mironid hopes that its lead candidate could curb both new cyst formation and existing cyst growth – addressing one of the root causes of the disease. Mironid also proposes that the drug may have a better side effect profile than Jynarque, potentially offering patients a more tolerable treatment option. This sentiment is backed by preclinical data, with the company claiming that studies have demonstrated the drug’s potential to reduce the number of cysts and kidney volume, while exhibiting a favourable safety profile. Abnormally elevated levels of cAMP are not just found in ADPKD, Wilkie adds, as several other diseases are also characterised by heightened cAMP signalling. This means that Mironid’s approach could hold potential across both other kidney diseases and conditions in different disease areas – something Wilkie says the company is currently investigating.

ART5 is designed to address the most common root cause of ADPKD by targeting PKD1, potentially restoring PC1 production in approximately 85% of patients First-in-human SAD study in healthy volunteers expected to initiate Q3 2026 Phase 1b study in patients with ADPKD planned for the first half of 2027 ADPKD affects an estimated 12 million people worldwide; approximately 50% develop end-stage kidney disease SAN DIEGO and SUZHOU, China, July 07, 2026 (GLOBE NEWSWIRE) -- Arnatar Therapeutics, a biotechnology company pioneering RNA-based therapies for severe and underserved diseases, today announced that the Center for Drug Evaluation (CDE) of China’s National Medical Products Administration (NMPA) has cleared the Company’s clinical trial application for ART5, a first-in-class up-regulating antisense oligonucleotide (ASO) therapeutic candidate for the treatment of autosomal dominant polycystic kidney disease (ADPKD). The first-in-human study is expected to initiate in Q3 2026. ADPKD is driven by mutations in the PKD1 or PKD2 gene, resulting in insufficient production of polycystin proteins that normally regulate kidney cell growth and fluid balance. Loss of polycystin-1 (PC1) function drives uncontrolled cyst development, progressive kidney enlargement, and irreversible loss of kidney function. ART5, developed through Arnatar’s proprietary ACT-UP1 platform, is designed to restore endogenous PC1 production directly at the source, correcting the underlying protein insufficiency that conventional gene-silencing approaches cannot address. “The initiation of our first-in-human study of ART5 represents a pivotal milestone for Arnatar and our mission to develop a potentially best-in-disease therapy for ADPKD,” said Xuehai Liang, Chief Executive Officer of Arnatar Therapeutics . “By restoring PKD1 expression to address the underlying cause of the disease, rather than treating its downstream consequences, we believe ART5 has the potential to become a truly disease-modifying therapy. We are excited to advance a program that we believe could redefine the standard of care for patients living with ADPKD.” ADPKD is one of the most common inherited kidney diseases, occurring in approximately 1 in 400 to 1 in 1,000 individuals and affecting an estimated 500,000 people in the United States alone. The disease is characterized by the progressive development of fluid-filled cysts in the kidneys and in some patients, other organs, leading to chronic pain, hypertension, cardiovascular disease, and progressive loss of kidney function; approximately 50% of patients develop end-stage kidney disease requiring dialysis or kidney transplantation. The only FDA-approved treatment, tolvaptan, carries a boxed warning for serious liver toxicity, and no approved therapy targets the root cause of the disease. In preclinical studies, ART5 demonstrated up to a two-fold increase in PC1 expression across human, mouse, and non-human primate (NHP) cells with no detectable off-target effects. In ADPKD patient-derived cells, PC1 upregulation was associated with reduced cAMP levels, decreased cyst formation, and lower cell proliferation, functional hallmarks of disease modification. In vivo, subcutaneous dosing produced durable increases in kidney PC1 protein in mice and NHPs, supporting the potential for convenient monthly or less frequent administration. The planned first-in-human Phase 1 study is a randomized, double-blind, placebo-controlled, single ascending dose (SAD) study designed to evaluate the safety, tolerability, pharmacokinetics, and pharmacodynamic activity of a single subcutaneous dose of ART5 in healthy volunteers. “This clearance further supports our ACT-UP1 platform and marks an important step toward expanding its application across haploinsufficiency diseases, where no adequate treatments exist. We look forward to the first clinical data for ART5 and advancing a potential new treatment option for patients with ADPKD,” added Dr. Liang. About Arnatar Therapeutics Arnatar Therapeutics is a clinical-stage biotechnology company redefining the possibilities of RNA medicine. With its proprietary DARGER™ platform, Arnatar uniquely integrates best-in-class siRNA gene silencing with first-in-class ACT-UP1 antisense oligonucleotides (ASOs) that upregulate protein expression. This dual-modality platform empowers Arnatar to develop RNA medicines that either silence harmful disease drivers through siRNA or restore essential protein function through up-regulating ASOs, opening new therapeutic possibilities for previously untreatable conditions. The Company’s pipeline spans cardiometabolic, liver, kidney, and central nervous system diseases, targeting areas of high unmet medical need. Founded by leaders in RNA therapeutics and backed by leading biotech investors, Arnatar is committed to transforming RNA innovation into life-changing, programmable medicines for patients worldwide. For more information, please visit . Contacts Jason Shieh Business Development bd_partnering@arnatar.com Chris Nardo LifeSci Advisors, LLC cnardo@lifesciadvisors.com