Abiraterone, which goes under the brand Zytiga, has prolonged Abdelbaset Ali Mohmed al Megrahi's survival since he was released from Greenock Prison by the Scottish Government in August 2009, because he had only three months to live.
Megrahi marks 1000 days today since being freed with his longevity a continuing controversy for the SNP Government.
Also today, the medicines regulator in England and Wales is to announce the drug will be made routinely available there.
The National Institute for Health and Clinical Excellence (Nice) says it can be used on prescription for terminally ill patients.
But patients in Scotland, where it has been rejected by the Scottish Medicines Consortium (SMC) in March, will only be able to access it through taking part in clinical trials, privately or if it is approved individually on a case by case basis.
Cancer charities have urged the watchdog to level the playing field for Scots patients, with more than 200 men a year likely to benefit from abiraterone.
Owen Sharp, chief executive of The Prostate Cancer Charity, said: "Abiraterone is a genuine breakthrough drug and we are delighted to see our argument that it is an end of life drug hit home. We will continue to appeal to ensure this decision is mirrored in Scotland."
Manufacturers Janssen had offered abiraterone to Nice at a special discount. Vicky Crichton, Cancer Research UK's public affairs manager in Scotland, said the charity was working to convince the SMC a deal like this can be done to make abiraterone affordable in Scotland.
Dr Rob Jones, a medical oncologist at Glasgow University's Institute of Cancer Sciences, who led clinical trials for abiraterone in Scotland, said he remained optimistic that the SMC would return a positive verdict later this year.
He said: "Abiraterone is a significant advantage for patients with a very advanced form of prostate cancer. It's not a cure and it's not a wonder-drug but it's the best we've had for some time. The benefits of this drug are very clear - Patients survived longer, pain control was better, quality of life was better, and the time to develop further complications from the cancer was improved."
Labour health spokeswoman Jackie Baillie MSP said: "Patients will be concerned if clinical evidence has been interpreted very differently in Scotland and other parts of the UK. There is always a balance to be struck between costs and clinical efficacy, but we need reassurance the SNP's cuts are not now influencing decisions."
In England, Abiraterone, which can cost £3000 a month, will be given to cancer sufferers who have already unsuccessfully had chemotherapy.
Janssen submitted a revised application to the SMC in April with a decision on the new bid expected on August 13. A spokesman for the SMC, which previously said the drug did not offer value for money, said their decisions could only be made on the evidence submitted to them.
A Scottish Government spokeswoman welcome the firm's decision to resubmit to the SMC.
At the weekend, the Prime Minister said the length of Megrahi's survival was an insult to the families of the victims of the Lockerbie bombing.