(Reuters) -The U.S. Food and Drug Administration on Monday granted accelerated approval to Pfizer's therapy for treating patients with a type of blood cancer that is difficult to treat, the company said.

The health regulator's decision allows use of the therapy, branded as Elrexfio, in patients with multiple myeloma that is hard to treat or has come back after receiving four or more prior lines of certain classes of treatments.

Elrexfio, or elranatamab, is administered under the skin and belongs to a class of therapies known as bispecific antibodies, that helps the body's immune system to kill cancerous cells by bringing a cancer cell and an immune cell together.

Pfizer has said the therapy could have more than $4 billion in potential peak revenue.

(Reporting by Bhanvi Satija and Leroy Leo in Bengaluru; Editing by Shounak Dasgupta)