The Australian doctors treating “Baby Z” appear to have made a wonderful, innovative discovery.

Unfortunately however, most “miracle cures” do not just suddenly appear. It takes on average ten to twelve years and about £500 million in investment to develop a medicine to the standards of quality, efficacy and safety laid down by law.

During this period only one or two compounds for every 10,000 evaluated gets as far as being granted a licence for use.

The point of the licensing process is to ensure that any new drug is reliable, safe and effective.

Doctors have some flexibility in using medicines “off-label” for other conditions where they think they might work. About half the medicines prescribed for children in hospital are either unlicensed or not licensed for that specific illness in a child of that age group. Trials are not typically carried out on children for ethical reasons.

The doctors in Melbourne have circumvented this process entirely, trying an unlicensed compound that had only ever shown promising results in mice.

They would normally only do this in life-threatening situations, where all other attempts at treatment have failed.

Only 26 cases of molybdenum cofactor deficiency type A have been diagnosed in Britain in the past five years, including some international patients.

It is usually a fatal disease, which occurs when babies are born with a genetic mutation that prevents them processing sulphite, which is produced naturally by the body as a by-product of metabolising proteins and minor acids.

Too much sulphite can be toxic to the brain. Babies with the mutation cannot produce enough of an enzyme which clears the chemical from the body, causing brain damage.

A complete deficiency of the enzyme, sulphite oxidase, means that babies usually die within the first 12 months. A number of patients can live longer but typically with progressive problems.

The compound discovered by German researchers acts to lower levels of sulphite, which may prevent extensive brain damage over time.

Baby Z, who is 18 months old, suffers developmental delay but her condition has improved remarkably.

Tony Marinaki, a clinical biochemist at the GSTS pathology laboratory at Guys and St Thomas’ Hospital, London, which diagnoses all cases of the condition in Britain, said: “There’s absolutely no treatment options for these babies at all at present, so this is really quite incredible.

“But it has to be used on patients who are newly diagnosed, within eight weeks of birth.”

Another drawback is that the chemical, cyclic pyranopterin monophosphate (cPMP), cannot be produced artificially and must be extracted from bacteria and grown in the laboratory.

There are also problems finding the money to develop medicines for rare conditions — those that affect fewer than 1,000 patients a year in Britain.

The German researchers are researching the incidence of the disease and plan to apply for a grant for the European Commission to bring the drug to market.

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