A Swindon woman with breast cancer returns to the High Court on Monday to continue her fight to force her local NHS trust to fund the drug Herceptin.
A full course of Herceptin is said to cost £30,000
Ann Marie Rogers, 54, is taking her plight to the Court of Appeal after losing her case last month.
She argues Swindon PCT has underspent its budget this financial year and says she faces "a death sentence" if they do not give her the drug.
The PCT says it will only fund the drug "exceptional circumstances".
Last month the High Court ruled that Ms Rogers should continue to receive the drug pending an appeal.
A statement from her solicitor said financial reports published by Swindon Primary Care Trust showed they expected to have underspent their annual budget by £750,000.
"So far, their case, against Ms Rogers, is estimated to have cost upwards of £50,000," said Yogi Amin, from firm Irwin Mitchell.
"Breast cancer patients want to ensure that their access to life-saving drugs, which their doctors prescribe, will not be overruled by a group of financial managers who decide whether they can be deemed an 'exceptional' person and that their life is 'exceptional' in some way.
"There is no good reason for the health authority to ration this essential drug treatment," Mr Amin said.
In a statement, Ms Rogers said she was "facing a death sentence".
"This battle against the bureaucracy created by hospital managers to receive the drug that my clinician has prescribed for me, has taken its toll and I am placing my faith in the court," she said.
Jan Stubbings, chief executive of Swindon PCT, said: "Swindon PCT is currently in an ongoing financially-balanced position.
"In the past we have been given financial support from other parts of the NHS and now the Avon, Gloucester and Wiltshire Strategic Health Authority has asked us to generate a £1.5m underspend to help the financial position in the region.
"The £750,000 balance is part of that total and are not funds available to us.
"We sympathise with Mrs Rogers and her family at this difficult time. The decision of the PCT not to support Herceptin in early stage breast cancer was upheld as lawful by the High Court.
"We feel we cannot comment further at this time, while the appeal process is taking place."
Full treatment with Herceptin costs an estimated £30,000.
It has been licensed in England and Wales for the treatment of advanced breast cancer and studies show it can halve the chances of an aggressive form of the disease returning.