Servier bets $450m on Fragile X syndrome drug

Servier has advanced its emerging neurology pipeline into the clinical trials stage by licensing a drug for the rare genetic disorder Fragile X syndrome (FXS) from UK biotech Kaerus Bioscience.

The French drugmaker is paying up to $450 million for rights to KER-0193, a small-molecule modulator of BK channels, a type of potassium channel in the brain that is thought to operate as a regulator of neuronal excitability across the nervous system. The drug is scheduled to start a phase 2 trial in Europe and the US next year.

FXS is the most common cause of inherited learning disability that causes a wide range of cognitive and behavioural challenges, occurring in both sexes by with boys generally more severely affected than girls, and is the leading single-gene cause of autism spectrum disorder (ASD). There are currently no approved treatments for the disorder.

According to Kaerus, KER-0193 address the abnormal function of BK channels that leads to hyperexcitability of neurons, which is a feature of FXS symptoms such as hyperactivity, anxiety, sensory hypersensitivity, and seizures that afflict some patients with the disorder.

The drug – which recently completed a phase 1 trial that Kaerus has said showed proof of concept based on electroencephalography (EEG) data – has been developed in close collaboration with the FRAXA Research Foundation, which is focused on supporting the development of FXS therapies.

In the study, KER-0193 showed that it was able to dampen down neuronal excitability in regions of the cortex that often read as abnormal in FXS patients. It has been given orphan drug and rare paediatric drug designations by the FDA.

For Servier, KER-0193 adds a clinical-stage candidate to a neurology pipeline currently represented by two preclinical assets, namely S230815 for a neurodevelopmental disorder and S233107 for a rare movement disorder.

The company has said it wants to build a pipeline in neurology that is focused on early-onset, genetically driven conditions that lead to neurodevelopmental, cognitive, or progressive neurological impairment and often have no treatments.

Servier's head of R&F, Claude Bertrand, noted that this is the first acquisition for Servier in neurology, and "marks a significant milestone in our 2030 strategy, reinforcing our long-term commitment to establishing a leading neurology franchise focused on rare diseases."

KER-0193 was set up by life sciences venture capital specialist Medicxi in 2016, specifically around the BK channel modulator programme, which also has potential in the treatment of patients with KCNMA1-linked channelopathies, a rare group of disorders characterised by seizures, movement disorders, developmental delay, and cognitive issues.