A charity says a decision by the NHS in England to reject a drug for men with prostate cancer is a "fiasco".
Abiraterone is already given to patients at the end-of-life after chemotherapy as it gives patients an extra few months.
But the National Institute for Health and Care Excellence said it was not cost-effective to offer it earlier.
It said while the drug improved quality of life, it was unclear whether it had the same impact on life expectancy.
This was due to problems with the research data, NICE said, claiming the trial was finished early - something disputed by the drug's makers Janssen.
Instead, patients will have to rely on their doctors applying to the Cancer Drugs Fund, a special pot set aside for cancer drugs not routinely available on the NHS.
Some 3,000 patients have done this in the last year, but that fund is due to end in 2016.
Owen Sharp, chief executive of Prostate Cancer UK, the largest men's health charity, said the whole process was "a fiasco".
He criticised NICE's inflexibility and the drug company's results-gathering process, saying: "This decision is a kick in the teeth for men with advanced prostate cancer.
"For many this presented a vital opportunity for extra time with loved ones and a chance to delay chemotherapy and the debilitating side-effects which come with it."
The decision comes just a week after NICE rejected a breast cancer drug called Kadcyla - again leaving the Cancer Drugs Fund as the only option for patients.
The drug normally costs £3,000 a month, but is given to the NHS for a discounted price after negotiations two years ago when the ruling on its use after chemotherapy was reached.
At the time it was hailed as a real breakthrough for patients with aggressive prostate cancer.
NICE chief executive Sir Andrew Dillon said he was disappointed not to be able to recommend abiraterone for use before chemotherapy.
He told BBC Radio 4's Today programme that pharmaceutical firms had to "balance their desire to make a profit" with the reality that the NHS had to meet all its needs.
"If we don't put in place arrangements to require drug companies... to look critically at what they are asking the NHS to pay, it will simply be a question of offering the keys to the safe and we can't do that," Sir Andrew said.
As well as the dispute about the way the research was conducted, this ruling has caused controversy because of the way NICE carried out the assessment.
When it assessed the drug for use after chemotherapy in 2012, NICE adopted its end-of-life criteria, which means it is willing to pay more.
For the latest assessment, it was judged to be a standard treatment.
The final guidance is expected later in the year, but major changes at this stage are considered unlikely.
While it will apply to England, the other UK nations also consider NICE's findings.
Janssen medical director Dr Peter Barnes said the firm was "very disappointed" and would appeal against the decision.