WASHINGTON: Expanding access to a promising but costly treatment, Medicare said Wednesday it will cover for some blood cancers a breakthrough gene therapy that revs up a patient’s own immune cells to destroy malignancies.

Officials said Medicare will cover CAR-T cell therapies for certain types of lymphoma and leukaemia, uses that are approved by the Food and Drug Administration. The cost can run to hundreds of thousands of dollars per patient, not counting hospitalization and other expenses.

Medicare Administrator Seema Verma said the decision will provide consistent and predictable access nationwide, opening up treatment options for some patients “who had nowhere else to turn.”

CAR-T uses gene therapy techniques to turbocharge the patient’s own immune system cells, reprogramming them to harbour a “receptor” that zeroes in on cancer, and then to grow hundreds of millions of copies. The revved-up immune cells are returned to the patient’s bloodstream and can continue to fight cancer for months or years.

Although side effects can be severe, studies have shown the treatment to be highly effective against certain types of cancers. Researchers are working to add more types to that list.

Medicare has been weighing the decision for months. The program often sets the tone for private insurance as well.

In its announcement, Medicare said it will cover CAR-T when the treatment is provided in institutions that are enrolled with the FDA in a special program to promote safety. It will also cover the treatment for other uses, if they are recommended by agency-approved medical research literature.

CAR-T uses a different strategy than other gene-therapy techniques. Instead of trying to fix disease-causing genes, it focuses on the patient’s immune system, specifically the T cells that battle foreign substances in the body. The problem with cancer is that malignant cells can often evade detection by the patient’s T cells. CAR-T helps the body’s own T cells do a better job of spotting tumours.

Medicare covers more than 60 million seniors and people with disabilities.