Molybdenum cofactor deficiency (MoCD) is characterised by early, rapidly progressive postnatal encephalopathy and intractable seizures, leading to severe disability and early death. Cyclic pyranopterin monophosphate (cPMP), a biosynthetic precursor of the cofactor.
In the study, 8 patients with type A disease rapidly improved under treatment and convulsions were either completely suppressed or substantially reduced. Three patients treated early remain seizure free and show near-normal long-term development. There was no biochemical or clinical response in patients with type B disease.
According to a commentary, this report is immensely encouraging for those who manage patients with genetic metabolic disorders, so often seemingly untreatable. The commentator notes the burdensome nature of this particular treatment—daily intravenous infusions for life –which could be argued is risky and interferes too much with quality of life to be in the best interests of the child. There is also the issue of cost as enzyme replacement therapies can cost hundreds of thousands of pounds per life-year gained.The costs of treatment for MoCD are not yet clear, but are likely to be very high. The commentator commends the researchers on this ‘exciting’ new treatment for a previously untreatable disease, but acknowledges the likely problems in assessing new treatments for rare diseases and the need for well designed long-term surveillance provided for treated patients.