Methylcobalamin (high dose)

Eisai is a large Japanese pharmaceutical company. It developed Rozebalamin after the JETALS trial, an investigator-led study run at 25 hospitals in Japan. Eisai filed for approval in Japan and sells the medicine there.

Methylcobalamin is an active form of vitamin B12. At very high doses it is thought to help protect nerve cells, though exactly how it could help in ALS is not proven. The dose (50 mg by injection) is thousands of times more than the B12 in food or ordinary supplements, so B12 tablets are not a substitute.

Eisai announced on September 24, 2024 that Rozebalamin had been approved for ALS in Japan. It went on sale in Japan on November 20, 2024. It is not approved by the FDA or in the EU or UK.

In the JETALS trial (130 people in Japan), the ALSFRS-R score fell 2.66 points on methylcobalamin versus 4.63 on placebo over 16 weeks, a 1.97 point difference. The trial was short and small, and only included people within a year of first symptoms who could still walk. That group was chosen after an earlier three-year trial (373 people) missed both its main goals; the benefit there appeared only when the data were re-analysed afterwards. Breathing and muscle strength did not differ in JETALS, and the drug changes urine colour, which could hint to participants which group they were in.

This is the most favourable result reported. See all key studies for the full picture.

JETALS enrolled people within one year of first symptoms who could still walk and had lung capacity above 60%. Each dose is 50 mg injected into a muscle twice a week. About 90% of trial participants were also taking riluzole. Side effects judged related to the drug occurred in 7.7% versus 1.6% on placebo.

In Japan, Rozebalamin is a prescription medicine covered by national health insurance. Outside Japan it is not approved; in the UK and some other countries, a doctor may be able to import it for an individual patient through a named-patient route. No trials are recruiting.