Servier acquires potential treatment for Fragile X syndrome, the most common genetic cause of autism spectrum disorder

• Servier acquires KER-0193, a potential treatment for Fragile X syndrome, developed by Kaerus Bioscience, a Medicxi company
• KER-0193, a novel, orally bioavailable small molecule, was granted Orphan Drug Designation and Rare Pediatric Drug Designation by U.S. FDA
• Acquisition strengthens Servier's neurology pipeline in line with its 2030 strategy

SURESNES, France, Sept. 8, 2025 /PRNewswire/ -- Servier, an independent international pharmaceutical group governed by a foundation, today announced that it has entered into a definitive agreement with Kaerus Bioscience for the acquisition of KER-0193, a potential treatment for Fragile X syndrome (FXS), the most common genetic cause of autism spectrum disorder (ASD). This acquisition demonstrates Servier's commitment to building a neurology franchise by expanding its pipeline with assets targeting rare indications for patients with high unmet need.

KER-0193 was discovered and developed by Kaerus Bioscience, a UK headquartered biotechnology company co-founded by Medicxi in 2016. Kaerus Bioscience successfully completed a Phase 1 clinical study of KER-0193 in healthy volunteers in March 2025, which confirmed the treatment to be safe and well tolerated with excellent pharmacokinetics. Additionally, KER-0193 has been granted both Orphan Drug Designation and Rare Pediatric Drug Designations for the treatment of FXS by the U.S. Food and Drugs Administration (FDA).

Under the terms of the agreement, Kaerus Bioscience will receive an upfront payment for the sale of KER-0193 and will also be eligible for development and commercial earn-out payments. The total value of the deal could reach up to $450M.

Claude Bertrand, Executive Vice-President of R&D at Servier, said: "KER-0193 is Servier's first asset acquisition in neurology and so marks a significant milestone in our 2030 strategy, reinforcing our long-term commitment to establishing a leading neurology franchise focused on rare diseases. It reflects our determination to build a differentiated pipeline of innovative therapies for patients with underserved needs. We are particularly excited to advance KER-0193 as we believe it holds meaningful promise for patients living with Fragile X syndrome, a condition for which no approved treatment options exist today." 

Dr. Robert Ring, Chief Executive Officer of Kaerus Bioscience, said: "We strongly believe in the therapeutic potential of KER-0193 in Fragile X syndrome. Servier's firm commitment to neurology and global capabilities make it the ideal partner to further develop KER-0193 for patients worldwide." 

Michèle Ollier, Venture Partner and co-founder of Medicxi, said: "Kaerus Bioscience was created by Medicxi to advance a clear product vision to develop a potential first-in-disease therapy for Fragile X syndrome. We are extremely proud of the cutting-edge scientific progress achieved by the Kaerus team under Dr Ring's leadership, and are excited that this deal with Servier will accelerate the development of KER-0193, bringing us closer to ensuring this innovative new therapeutic can reach those patients who are most in need."

KER-0193 is an orally bioavailable small molecule modulator of BK channels that specifically addresses abnormal function of BK channels linked to the genetic cause of FXS. In preclinical studies, KER-0193 has already demonstrated broad therapeutic-like effects on improving syndrome-relevant behavioral, sensory and cognitive deficits. As part of the development strategy, Servier will prepare the launch of a Phase 2 clinical trial in 2026 in FXS patients in America and Europe. 

FXS is a rare genetic syndrome of neurodevelopment characterized by a wide range of cognitive and behavioral challenges. It is the most common genetic cause of intellectual disability and the leading single-gene form of autism spectrum disorder (ASD), affecting approximately 1 in 7,000 males and 1 in 11,000 females globally. There are currently no approved treatments for FXS, which accounts for approximately 1% of ASD and intellectual disability cases globally.

Servier media contacts:

Olympe Muller
olympe.muller@servier.com

Kaerus Bioscience media contacts:
Optimum Strategic Communications 
Hana Malik, Stephen Adams
Tel: +44 (0) 20 3882 2119
Email: kaerus@optimumcomms.com

About Servier

Servier is an independent international pharmaceutical company governed by a nonprofit foundation, committed to making a meaningful social impact for patients and contributing to a sustainable world. Its unique governance model ensures its independence, while supporting long-term innovation, with 100% of its profits reinvested in the Group's development. 

As a world leader in hypertension and venous diseases and a major player in cardiometabolism, Servier drives transformative innovation to support patients with chronic conditions and improve their day-to-day lives through a holistic approach, which includes making patient adherence and control a priority across the globe. Its ambition is to become a leading player in rare cancers, which is why the Group invests heavily in oncology, allocating close to 70% of its R&D budget to this field. By leveraging precision medicine, Servier develops therapies that are more targeted and more effective.

Bolstered by its success in oncology, Servier has expanded into neurology, a key driver of future growth. The Group is focused on a select number of neurological diseases, where accurate patient profiling enables targeted therapeutic responses through precision medicine. 

To open up wider access to high-quality, affordable care, Servier also offers an extensive range of generic medicines, building on well-established brands in France, Eastern Europe, and Brazil. In all its activities, and at every stage of the medicine life cycle, the Group integrates the patient's voice. 

Headquartered in France, Servier operates in around 140 countries. In 2023-2024, the Group, which employs over 22,000 people worldwide, achieved revenues of €5.9 billion. 

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About Kaerus Bioscience

Kaerus Bioscience is a UK-based clinical-stage biopharmaceutical company established by Medicxi for the development of therapeutics for rare genetic syndromes of neurodevelopment. Kaerus has developed a pipeline of targeted, small molecule therapeutics that address an underlying ion channel dysfunction in Fragile X syndrome, which is the most common inherited cause of intellectual disability and autism spectrum disorder (ASD) globally.

For more information about Kaerus, please visit www.kaerusbio.com.

About Medicxi

Medicxi is a healthcare-focused investment firm with the mission to create and invest in companies across the full drug development continuum. Leveraging deep expertise in drug development and company creation spanning over two decades, Medicxi invests in early and late-stage therapeutics with a product vision that can fulfil a clear unmet medical need. For more information, please visit: www.medicxi.com

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