Pyridoxal phosphate

Table of contents

• What is pyridoxal phosphate?
• How does pyridoxal phosphate work?
• Which conditions is it used or studied for?
• How is pyridoxal phosphate given?
• What do the clinical trials show?
• What side effects are known?

What is pyridoxal phosphate?

Pyridoxal phosphate is a chemically synthesised substance that belongs to the nervous system disease area. It is being developed for the treatment of seizures associated with pyridox(am)ine 5'-phosphate oxidase (PNPO) deficiency, a rare inherited condition.^[1] The substance is also listed in the NHS dm+d browser as a virtual therapeutic moiety, where it appears in several formulations including capsules and tablets of 25 mg and 50 mg, an oral suspension of 100 mg/5 ml, and gastro-resistant tablets.^[2]

Pyridoxal phosphate has orphan designation in one product record, meaning it is intended for a rare disease. It has no marketing authorisation in the records examined, so it remains an investigational substance. The product is supplied by Medicure.^[1]

How does pyridoxal phosphate work?

PNPO deficiency is a condition in which the body cannot convert pyridoxine (vitamin B6) into its active form, pyridoxal phosphate. This active form is needed for many chemical reactions in the brain. By giving pyridoxal phosphate directly, the treatment aims to bypass the missing enzyme step and provide the active substance that patients cannot make themselves.^[1]

Which conditions is it used or studied for?

Pyridoxal phosphate is being studied for one condition in the registered trial:

• Seizures associated with PNPO deficiency — a rare inherited disorder of the nervous system in which affected people, often infants, have seizures that do not respond to usual vitamin B6 treatment.^[1]

How is pyridoxal phosphate given?

In the registered trial, pyridoxal phosphate is given as a tablet taken by mouth. The trial intervention lists a dose of 3 grams.^[1] The NHS dm+d browser also lists other pharmaceutical forms of pyridoxal phosphate, including 25 mg and 50 mg capsules, 25 mg and 50 mg tablets, 50 mg gastro-resistant tablets, and a 100 mg/5 ml oral suspension.^[2]

What do the clinical trials show?

One clinical trial of pyridoxal phosphate is registered in the EU Clinical Trials Information System. It is a Phase 3 interventional study, the most advanced phase of testing before potential authorisation. The trial is currently authorised, meaning it has received regulatory approval to begin, but it is not yet listed as recruiting.^[1]

The trial plans to enrol 3 participants with confirmed PNPO deficiency. The main outcome measure is the incidence of death at 12 months, which will be compared between the study group and an external control group of patients who did not receive pyridoxal phosphate treatment.^[1]

The study is designed to evaluate the effectiveness of oral pyridoxal phosphate, referred to in the trial as MC-1, for the chronic treatment of patients with confirmed PNPO deficiency.^[1]

What side effects are known?

The sources provided do not contain information on side effects of pyridoxal phosphate. The trial registry record does not list adverse events, and the NHS dm+d browser entry contains only naming and formulation details.^[2]