Enthorin Therapeutics licenses experimental Fragile X drug candidate to Rumi Therapeutics

**USA— **Enthorin Therapeutics has signed an option-to-license agreement with Rumi Therapeutics in the USA to advance an experimental treatment for Fragile X syndrome (FXS) and other intellectual and developmental disabilities.

Under the agreement, Rumi Therapeutics will assume responsibility for developing ENT-7340, which it will rename RTX-7340.

Enthorin will receive an upfront payment and an option exercise fee, alongside milestone payments tied to development, regulatory and commercial progress.

The company will also qualify for royalties on future net product sales and provide scientific and technical support during the initial development stages.

PDE2A inhibition targets neurological pathways

ENT-7340 is an investigational small-molecule drug candidate that selectively inhibits phosphodiesterase 2A (PDE2A), an enzyme that regulates cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) signalling.

These pathways influence neuronal communication, brain function and synaptic plasticity, which are important for learning, memory and behaviour.

FXS is an inherited neurodevelopmental condition caused by changes in the Fragile X messenger ribonucleoprotein 1 (FMR1) gene.

These changes reduce or prevent the production of fragile X messenger ribonucleoprotein (FMRP), a protein essential for normal brain development.

People with the condition can experience varying degrees of intellectual disability, language difficulties, behavioural challenges and sensory processing problems.

Research conducted by Enthorin indicates that disrupted cyclic nucleotide signalling contributes to the neurological changes associated with FXS.

In preclinical studies, ENT-7340 demonstrated activity across behavioural and neurophysiological measures in Fragile X mouse models, including improvements in cognition-related and autism-associated behavioural abnormalities.

The company also reported PET imaging evidence of target engagement, providing a basis for investigating the relationship between drug exposure, PDE2A inhibition and biological effects.

Human organoid models to support development

Rumi Therapeutics plans to use human cellular and organoid disease models to investigate the candidate’s mechanism of action and evaluate its therapeutic potential.

These models reproduce selected features of human tissues and can help researchers assess drug responses before clinical testing.

Marco Peters, co-founder and chief scientific officer of Enthorin Therapeutics, said the programme represents years of research into PDE2 inhibition as a potential treatment approach for neurodevelopmental disorders.

He noted that Rumi’s expertise in human cellular and organoid models would help validate the drug’s biological activity and investigate its potential across FXS and other conditions.

Enthorin developed the programme with research support from the FRAXA Research Foundation, which has funded studies into the molecular effects of FMRP loss and the role of cyclic nucleotide signalling in Fragile X.

Michael Tranfaglia, medical director and co-founder of FRAXA, said the advancement of RTX-7340 provides another opportunity to translate research into potential treatments for people living with the condition.

The agreement transfers further development responsibilities to Rumi, while allowing Enthorin to retain financial participation through milestone payments and future royalties. Rumi operates alongside Rumi Scientific under parent company Rumi Holdings.

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