Scientists in the UK have discovered that a common and inexpensive arthritis drug may be effective against blood cancer.

According to the researchers, the drug, methotrexate has shown potential to treat a rare blood disorder known as myeloproliferative neoplasms (MPN).

MPN is the name for a group of chronic rare blood diseases in which the bone marrow makes too many red blood cells, platelets, or certain white blood cells. People with MPN are most often diagnosed in their 50s and 60s.

Methotrexate is commonly used at low doses to treat inflammatory diseases including rheumatoid arthritis, Crohn's disease, and psoriasis. It has few side effects. It may work as well against MPN as another drug, called Jakafi (ruxolitinib), which costs $84,000 a year, researchers said.

In their study, the researchers used cells from the fruit fly Drosophila to screen for small molecules that suppress the signaling pathway central to the development of MPNs in humans. Further testing confirmed this in human cells, even those carrying the mutated gene responsible for MPNs in patients.

In the U.S., Jakafi is one of the drugs approved for use in treating MPN, but it is not allowed in the UK because of its prohibitive cost. The UK scientists are hoping their finding could help make methotrexate treatment accessible throughout the world.