The federal government will subsidise a cancer drug that gives hope to mantle cell lymphoma patients who suffer a relapse along with three other cancer drugs.

An expensive cancer drug that treats an aggressive form of lymphoma will be subsidised from next month, making it affordable for hundreds of patients.

The drug Imbruvica is used to treat mantle cell lymphoma when there's a relapse after chemotherapy and would cost patients about $134,000 a year if it is not subsidised.

Federal Health Minister Greg Hunt has announced that from August 1, Imbruvica will be available through the Pharmaceutical Benefits Scheme.

It will join three other medicines that treat head and neck cancer, blood cancer and the side effects of chemotherapy.

"Its total cost of $250 million will help save and protect the lives of thousands of patients each year," Mr Hunt told reporters in Melbourne on Sunday.

"This will give life-saving or life-changing access to families.

"I hope there are many families who will be able to take a big sigh of relief, a sigh of relief on financial grounds, but most importantly on health grounds."

The four medicines are expected to help 4000 to 5000 people a year, Mr Hunt said.

Associate Professor Constantine Tam has been treating patients with Imbruvica in a clinical trial at Melbourne and said the drug worked by targeting a gene the cancer needs to survive, but is not needed by the rest of the body.

Patient Ertugrul Delibalta is a 70-year-old aged care pensioner who was first diagnosed the mantle cell lymphona about six years ago and relapsed after about three years.

"They said we cannot do the chemotherapy again because if we do the chemotherapy again we kill you," Mr Delibalta told reporters.

Mr Delibalta said he was put on Dr Tam's trial - a life and cost saving move - because "it would have been too hard and I would have died" if he pad to pay for the drug.