A randomized, double-blind and placebo-controlled study involving Stanford University School of Medicine researchers showed that people with myelofibrosis – blood cancer – can benefit from ruxolitinib, the first FDA-approved therapy for myelofibrosis. Ruxolitinib blocks the JAK2 tyrosine kinase protein that is both mutated and unusually active in 50 to 60 percent of myelofibrosis patients.

Myelofibrosis patients in the advanced stage suffer from worsening blood counts, spleen enlargement and other sporadic symptoms such as fever, night sweats and muscle and bone pains. Patients in the study reported decreases in these symptoms when given ruxolitinib.

In the trial, 155 patients received ruxolitinib while 154 took a placebo twice daily. The two groups’ spleen volumes were measured over 24 weeks via magnetic resonance imaging with the primary endpoint for the study at a 35 percent reduction in the spleen volume.

Approximately 46 percent of patients on ruxolitinib reported experiencing a 50 percent or greater improvement in their myelofibrosis symptoms. Five percent of patients receiving the placebo drug reported the same improvement of their symptoms.

Myelofibrosis, affecting roughly 30,000 people in the United States, is one of the many myeloproliferative neoplasm (MPN) diseases that affect approximately 150,000 people in the United States. MPN diseases are characterized by the overproduction of red blood cells, platelets or white blood cells by the patient’s bone marrow. This overproduction can lead to scarring within the bone marrow, thus decreasing the bone marrow’s blood-making ability.

The multi-site phase-3 trial, published March 1 in the New England Journal of Medicine, was led by researchers at the MD Anderson Cancer Center in Houston and the Mayo Clinic in Scottsdale, Ariz. Jason Gotlib, an associate professor of medicine, managed the Stanford University School of Medicine researchers who participated in the trial. With 15 participating patients, Stanford was the single largest recruiting site in the 300-patient, 89-site trial.

“Ruxolitinib doesn’t cure the disease, but the degree of benefit is clinically meaningful and substantial and allows many patients to re-engage in their daily activities,” Gotlib said in a School of Medicine press release.

In November, the FDA approved the treatment for patients with intermediate to advanced cases of myelofibrosis. Ruxolitinib is called Jakafi when marketed and is produced by Incyte, Corp., which also funded the clinical trial.

Hagop Katarjian, chair of the department of leukemia in the Division of Cancer Medicine at MD Anderson Cancer Center, is the study’s senior author. Srdan Verstovsek, an associate professor in Katarjian’s department, was the first author of the study.

— Alice Phillips