Focalis Bio, formerly EpilepsyGTx, develops gene therapies for focal refractory epilepsy. Its investigational EPY201 programme uses an adeno-associated viral vector to deliver an engineered potassium channel directly to the seizure focus, aiming to reduce neuronal hyperexcitability without removing or destroying brain tissue. The UCL spinout is preparing clinical evaluation of a potential single-dose therapy and developing a broader pipeline for disorders of neuronal hyperexcitability.