A cancer patient with only months to live will learn today whether he can have the costly drug that specialists say could extend his life by up to three years.

Colin Ross, 55, has challenged his local primary care trust's refusal to fund his treatment with up to four courses of Revlimid, which costs £5,000 per course but has yet to be assessed by the medicines watchdog, the National Institute for Clinical Excellence.

Mr Ross, of Horsham, West Sussex, was diagnosed with multiple myeloma, a cancer of the blood cells, in May 2004. Doctors at the Royal Marsden Hospital in London say Revlimid is his last chance after side-effects forced him to give up other life-prolonging drugs.

Today, the High Court will announce the findings of its judicial review of the refusal of funding by West Sussex Primary Care Trust. Mr Ross's case against the trust, which twice rejected his request for Revlimid, is backed by Professor Karol Sikora, a cancer specialist who was an expert witness.

Professor Sikora said: "To me this is an ideal case. If you don't say Mr Ross's case is exceptional, then nothing would be." Patients in neighbouring East Sussex had been prescribed the drug on the NHS, he added.

Mr Ross's action is the latest to highlight pressures on the NHS cancer drugs budget. Professor Sikora claimed the 10 treatments already licensed and 40 in the pipeline could see the cost of cancer care soar to £50bn by 2012, consuming half the NHS budget and causing "meltdown".

However, senior figures in the NHS dismissed his estimates as "nonsense" and "hyperbole", pointing out that the drugs extended patients' lives by months, not years, so the extra costs did not last long.