America's powerful drugs regulator has fast-tracked new trials of an Australian-invented bone marrow transplant treatment for critically ill cancer patients.

The green light from the Food and Drug Administration (FDA) puts the Melbourne-based Mesoblast a key step closer to making its revolutionary stem cell medicine available to thousands of patients needing bone marrow transplants.

More than 60,000 bone marrow transplants are carried out around the world annually to help save the lives of people, including patients with leukaemia and lymphoma.

About 25,000 have transplants using their own stem cells, which help replace damaged or destroyed bone marrow and promote the growth of new blood cells.