HealZen Therapeutics has recently announced that the self-developed innovative drug, HZ-A-018 capsule, a Bruton's tyrosine kinase (BTK) inhibitor, has been granted approval by the National Medical Products Administration (NMPA) to conduct clinical trials for relapsing multiple sclerosis (RMS) and neuromyelitis optica spectrum disorders (NMOSD).

MS is an immune-mediated chronic inflammatory demyelinating disease that affects the central nervous system. It often involves various areas such as periventricular, juxtacortical, optic nerve, spinal cord, brainstem, and cerebellum. Due to its broad range of lesions, repeated attacks can lead to disability or even death. Although there are several drugs approved for MS treatment, it remains incurable. There are still urgent needs for more effective treatment options.

NMOSD is an autoimmune-mediated central nervous system inflammatory demyelinating disease that mainly impact the optic nerves and spinal cord. Clinically, severe optic neuritis and longitudinally extensive transverse myelitis are the main features. The recurrence rate and disability rate are high, and over 90% of patients have a relapsing course, most patients left with significant neurological disabilities. At present, there is a lack of effective therapeutic drugs for NMOSD in China, and there is a huge unmet demand in clinical practice.

BTK inhibitors have the potential to become a new type of treatment for autoimmune diseases such as RMS and NMOSD because they can simultaneously target the peripheral immune system and the inflammatory environment of the central nervous system. HZ-A-018 is a highly selective small molecule BTK inhibitor with excellent kinase selectivity and blood-brain barrier permeability. In vitro studies show that it can effectively inhibit B cell activation and differentiation and improve the symptoms of EAE model mice, bringing new treatment options for RMS and NMOSD patients.

References
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