A new drug used to treat patients with chronic myeloid leukemia (CML) and Philadelphia chromosome positive acute leukemia (Ph+ ALL) has just received approval from the U.S. Food and Drug Administration.

The drug, Iclusig (ponatinib), was expected to be approved on March 27, 2013, but as there is no alternative therapy that currently exists for the two rare blood and marrow diseases, the FDA prioritized it's review.

The drug works among leukemia patients who don't respond to treatment from a class of drugs called tyrosine kinase inhibitors (TKIs). It works by blocking proteins that cause cancerous cells to develop. Sometimes the cancerous cells can develop a mutation called T315I which makes them resistant to TKIs, Iclusig is effective at targeting these cells.

According to Richard Pazdur, M.D., director of the Office of Hematology and Oncology Products in FDA's Center for Drug Evaluation and Research:

"The approval of Iclusig is important because it provides a treatment option to patients with CML who are not responding to other drugs, particularly those with the T315I mutation who have had few therapeutic options. Iclusig is the third drug approved to treat CML and the second drug approved to treat ALL this year, demonstrating FDA's commitment to approving safe and effective drugs for patients with rare diseases."

449 patients with CML and Ph+ALL participated in the clinical trial to evaluate the effectiveness of the drug. The researchers found that that there was a significant reduction in the number of cancerous cells with the Philadelphia chromosome genetic mutation, achieving major cytogenetic response (MCyR). MCyR was achieved in 70 percent of patients with the T315I mutation and in 54 percent of all patients.

During the accelerated and blast phase CML and Ph+ ALL they found that 52 percent of participants with accelerated phase CML experienced no evidence of leukemia (major hematologic response, MaHR) for a median period of 9.5 months. 31 percent of participants with blast phase CML experienced major hematologic response for a median period of 47 months. And 41 percent of participants with Ph+ ALL achieved MaHR for a median period of 3.2 months.

Side effects of the drug include high blood pressure, abdominal pain, headache, dry skin, joint pain, fever and nausea. The drug will also be labeled with a warning alerting patients of the increased risk of developing blood clots and liver toxicity associated with taking the drug.

Written by Joseph Nordqvist