A drug currently used to treat advanced breast cancers may treat a rare type of leukemia known as myelofibrosis. The study was published in Cancer Research by scientists at the University of Virginia Health System.
Myelofibrosis is a form of leukemia- cancer of the blood and bone marrow. It typically occurs in those who are middle-aged or older and affects between 1 and 1.5 in every 100,000 people. Those with advanced stages of the disease have a median survival time of 1.5 to 2.3 years.
Ruxolitinib, a kinase inhibitor, is used to relieve symptoms of the disease. The drug, however, does not address the disease's characteristic feature, bone marrow scarring. Scarring both disrupts the marrow's production of red blood cells- causing severe anemia- and reduces the number of platelets in the blood, making clotting difficult and enlarging the spleen.
Previous studies have found that palbociclib, a cyclin-dependent kinase (CDK) inhibitor, reduces activity in the bone marrow of patients with advanced stages of breast cancer. Researchers thus sought to see how patients with myelofibrosis would respond to the drug.
In experiments involving mouse models of myelofibrosis, the researchers showed that palbociclib was able to reduce bone marrow scarring. It also decreased excessive levels of white blood cells and shrank their enlarged spleens.
They then found that, when combined with ruxolitinib, palbociclib was able to restore bone marrow in mice, normalize white blood cell counts, and further reduce the size of enlarged spleens.
"A combinatorial therapeutic approach involving palbociclib and ruxolitinib will enable lowering the doses of each of the inhibitors and thus reducing toxicities while enhancing the therapeutic efficacy," wrote the researchers in their paper.
"The findings from this study are very exciting, and they support the clinical investigation of palbociclib and ruxolitinib combination in patients with myelofibrosis," said Golam Mohi, one of the authors of the paper.