A drug initially developed for high blood pressure, SOM3355 (bevantolol hydrochloride), has demonstrated potential in treating Huntington's disease, thanks to an artificial intelligence-based drug discovery program by Spain's SOM Biotech. In a phase 2 trial involving 32 patients, SOM3355 significantly improved the involuntary, jerky movements known as chorea, a key symptom of Huntington's disease.
- 57.1% of patients treated with SOM3355 experienced a two-point or greater reduction on the total maximal chorea (TMC) score compared to the control group.
- 28.6% and 25% of patients achieved a three- or four-point reduction in TMC scores, respectively.
- 17.9% and 10.7% of patients saw a five-point and six-point reduction, respectively.
The drug, which functions as a beta blocker and inhibits vesicular monoamine transporter 2 (VMAT2), is already marketed by Nippon Chemiphar as Calvan for hypertension in Japan, South Korea, and China. Its potential for Huntington's disease was identified through SOM's AI drug screening platform, which repurposes existing drugs for new indications.
SOM3355's safety profile appears favorable, with only mild or moderate adverse events reported, such as headache, fatigue, nausea, and vomiting. This contrasts with the severe side effects associated with Lundbeck's Xenazine, a well-established VMAT2 inhibitor used to treat chorea in Huntington's disease, which includes sedation, parkinsonism, and risks of depression and suicidality.
SOM Biotech plans to advance SOM3355 into a phase 2b trial later this year, aiming to address the "huge unmet medical need" for new Huntington's disease treatments. The company's CEO, Raúl Insa, predicts peak sales could reach €1.1 billion, despite competition from Teva's Austedo and Neurocrine Biosciences' Ingrezza, both of which also target Huntington's chorea with fewer side effects than Xenazine.
