Kaerus Bioscience's lead candidate KER-0193 granted Orphan Drug Designation and Rare Pediatric Drug Designation by U.S. FDA for treatment of Fragile X syndrome (FXS)

• FDA's two designations demonstrate KER-0193's potential as a treatment for FXS
• Follows the successful completion of Phase 1 clinical trial
• Fragile X syndrome is the most common cause of inherited autism

LONDON, May 14, 2025 /PRNewswire/ -- Kaerus Bioscience ("Kaerus" or "the Company"), a clinical stage biopharmaceutical company created by Medicxi for the development of therapeutics for rare genetic syndromes of neurodevelopment, today announces that its lead candidate KER-0193 has been granted both Orphan Drug Designation and Rare Pediatric Drug Designations for the treatment of Fragile X syndrome (FXS) by the U.S. Food and Drugs Administration (FDA).

It follows the recent successful completion of a Phase 1 trial of KER-0193 in healthy volunteers, which confirmed the drug to be safe, well tolerated and exhibit excellent pharmacokinetics.

FXS is an inherited condition, affecting about 1 in 7,000 males and 1 in 11,000 females, for which there are currently no approved treatments. It is the most common cause of inherited autism and intellectual disability, accounting for approximately 1 per cent of such cases globally.

Dr Robert Ring, CEO of Kaerus Bioscience, said: "The FDA's granting of Orphan Drug Designation and Rare Pediatric Drug Designation for KER-0193 is an important step towards our objective of delivering an effective treatment for people with Fragile X syndrome.

"Not only do these two FDA designations affirm the therapeutic potential of KER-0193 in Fragile X syndrome, they also provide Kaerus with access to significant regulatory and financial incentives as we look to progress the drug through clinical trials and ultimately take it to market."

Paul Sekhri, Chairman of Kaerus Bioscience, said: "These important FDA designations are more excellent news for Kaerus, coming after the impressive Phase 1 results showing KER-0193 to be safe and well-tolerated. These developments put the Company in a superb position as we  look to move into Phase 2 trials."

Both FDA programmes are aimed at encouraging the development of treatments for rare diseases.

Discovered by Kaerus, KER-0193 is a novel, orally-bioavailable small molecule designed to specifically address hyper-excitability of brain function commonly associated with Fragile X syndrome. KER-0193 does this by targeting BK channels (calcium-activated potassium channels), which have been described as master regulators of excitability across the nervous system. The genetic cause of FXS is directly linked to a reduction in BK channel function.

Based on its broad efficacy profile in preclinical genetic models of FXS, Kaerus is excited by the therapeutic potential of KER-0193 to address the diversity of behavioural, sensory and cognitive challenges that adversely impact the lives of individuals with FXS.

Kaerus's conviction has been strengthened by a pre-planned sub-study, conducted during the Phase 1 trial, in which the effects of KER-0193 on brain activity in healthy volunteers were investigated using electroencephalography (EEG). The study convincingly demonstrated that KER-0193 enters the brain and produces pharmcodynamic effects on brain activity in regions often implicated in patients with FXS. These results replicated observations from EEG profiling of KER-0193 in preclinical animal studies, demonstrating proof of mechanism.

Beyond FXS, reduced BK channel activity has been implicated in a number of other neurological conditions, including epilepsy and several rare genetic epileptic encephalopathies.  

Dr Ring said: "We are actively exploring opportunities to expand the therapeutic potential of our BK modulator platform to these other indications, where patient populations struggle with significant unmet treatment needs."

The company is finalising preparations for a Phase 2 proof-of-concept study in FXS patients.

About Kaerus

Backed by Medicxi, Kaerus Bioscience Ltd is a clinical-stage biotechnology company committed to turning scientific advances into treatment realities for patients with 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 globally.

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

About KER-0193

KER-0193 is a novel, proprietary, and orally-bioavailable small molecule modulator of BK channels discovered by Kaerus. KER-0193 specifically addresses abnormal function of BK channels linked to the genetic cause of Fragile X syndrome. KER-0193 has already demonstrated broad effects on improving syndrome-relevant behavioural, sensory and cognitive deficits observed in genetic animal models of Fragile X. Fragile X syndrome, which affects about 1 in 7,000 males and 1 in 11,000 females, is the most common inherited cause of autism and intellectual disability globally. There are currently no approved treatments for Fragile X.

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: https://www.medicxi.com