A Combination Leukemia Can’t Take

Chronic lymphocytic leukemia responds to combination of ibrutinib and rituximab

(RxWiki News) Many patients with chronic lymphocytic leukemia do pretty well with standard treatment. The disease retreats and stays in remission. However, some patients aren’t so fortunate. A new combination may be just what these patients need.

A phase 2 clinical trial has found that a combination of two medications –​ ibrutinib and rituximab (Rituxin) – effectively quelled aggressive chronic lymphocytic leukemia (CLL). The dual therapy produced only minor side effects in the study.

"If you notice lymph node swelling, visit your doctor."

The trial was conducted at The University of Texas MD Anderson Cancer Center and led by Jan Burger, MD, PhD, associate professor in MD Anderson's Department of Leukemia.

CLL is the most common type of leukemia. It will be diagnosed in about 16,000 Americans this year, and about 4,500 will die from the disease that strikes mostly older individuals.

The standard treatment for CLL involves chemotherapy, which while effective against the disease, can be highly toxic. In fact, the treatment is known to cause other fatal cancers.

One of the drugs in the therapy – ibrutinib – is a new medication still in clinical trials that appears to have potential in treating other blood cancers, including certain types of lymphoma (cancer of the lymph system) and myeloma. Its success with CLL has been particularly noteworthy.

Researchers have found that while response to ibrutinib has been impressive, a condition known a lymphocytosis (an increase of leukemia cells in the blood) often interferes. That’s why rituximab was added. This widely used antibody catches CLL cells in the blood, which in turn improves overall response.

"When we looked at how well the high-risk patients were doing on ibrutinib - even though it was a small number - we saw a great opportunity to find out if combining the two drugs would have a positive impact on these patients," Dr. Burger said in a statement.

For this study, 40 CLL patients were enrolled, 38 of whom continued on the therapy for four months without the disease getting worse.

After three months, the responses of 20 patients were evaluated. The overall response rate was 85 percent, with 17 patients achieving partial remission. The other three patients had partial remission, but with lymphocytosis.

Patients tolerated the therapy well, with the most serious side effects being insomnia, bone pain, fatigue, pneumonia and a lowering of white blood cell count.

According to a statement reporting on the study, the researchers think these results along with previous trials, “emphasize the need for rapid further development of ibrutinib for high-risk CLL patients.”

Results from this study were presented at the 54th annual meeting of the American Society of Hematology (ASH). All research is considered preliminary before it's published in a peer-reviewed journal.

Review Date: 
January 27, 2013