Temozolomide, marketed as Temodal, has been granted a licence by the European Medicines Evaluation Agency and was launched in the UK on Thursday.

It will be available on the NHS from next month for adults and children with advanced brain cancer.

However, many health authorities are likely to ration it as it costs around �1,000 for a monthly course of treatment.

But because it is so easy to take, it can be taken on an outpatient basis, saving money on hospital treatment.

In tests, Temodal has been shown to boost survival rates as well as reducing the side effects of other treatments.

And experts say it could eventually have a big impact on other cancers.

The capsule-form drug treats the most common and deadly form of brain tumour, glioblastoma multiforme. This affects around 2,000 people a year in the UK.

Professor Malcolm Stevens, who helped develop the drug, says there are very few orally taken cancer drugs.

"It is much more convenient for patients," he said.

The drug was developed by the Cancer Research Campaign (CRC) in conjuction with drugs company Schering Plough.

The deal means substantial royalties from sales of the drugs will be ploughed back into the CRC's research work.

Remarkable results

Professor Gordon McVie, director general of the CRC, said the drug was "the most important advance in brain cancer treatment for the past 20 years".

Professor McVie: Temodal could revolutionise cancer care

Professor Stevens was more modest, saying it remained to be seen how big the drug's impact was.

"It is a new adventure," he said, but he agreed trial results were exciting.

"There aren't any successful drug treatments for this form of brain cancer," he stated. "Only chemotherapy and radiotherapy, but they do not really do any more than buy a short period of time."

The trials were conducted on people with advanced brain cancer for whom other treatment had not worked.

"They were exceedingly ill ," said Professor Stevens. "We can only speculate on what the drug would do for people with small tumours."

He added that the drug could be used in combination with other drugs and treat other cancers.

Temodal will initially prescribed on a monthly basis and taken over five days by patients who have not responded to surgery and radiotherapy.

If it works, patients will get another monthly dosage and use it until their cancer recedes.

Temodal works by damaging DNA in brain cancer cells and causing them to commit suicide.

Non-cancerous cells are not harmed and, unlike most cancer treatments, it can filter through the brain's protective barrier.

Compassionate grounds

It is the first of the CRC's drugs to be given to patients on compassionate grounds before it was granted a licence.

This was due to the "very positive results" it obtained in preliminary trials.

The drug was among a batch of chemicals which were synthesised in the late 70s at Birmingham's Aston University.