BY JON GARINN | JUNE 5, 2011
Until now, patients with myelofibrosis, a rare type of leukemia, had few options for relief from one of the most pernicious symptoms: an enlarged spleen. But a new study, coupled with a previous phase 3 study from last year, shows significant benefit compared with currently available therapies.
Myelofibrosis is a disorder in which mutant bone marrow stem cells disrupt the production of healthy blood cells, resulting in scarring of the normally spongy bone marrow. Because the compromised bone marrow cannot produce an adequate amount of blood cells, the liver and spleen try to make up for it, causing the organs to swell.
The condition affects about 3,500 people in the U.S. annually, with more than one-fourth of patients eventually developing bone marrow failure and other disabling symptoms such as anemia. All patients have an autonomously activated Janus kinase (JAK) pathway, which regulates blood cell production.
In the randomized phase 3 study, researchers showed that ruxolitinib, a JAK inhibitor, delivered rapid, significant and lasting spleen size reduction in patients. After 24 weeks, 31.9 percent of 146 patients receiving the drug achieved 35 percent or greater reduction in spleen size compared to 0 percent of 73 patients receiving the best available therapy.
"This therapy has the potential to significantly change the treatment landscape for these patients, and could greatly improve their outlook," says Alessandro Vannucchi, MD, of the University of Florence in Florence, Italy. "We've urgently needed new treatments for this condition."RELATED POSTS