The approval of dasatinib, an oral kinase inhibitor, has been expanded to include the initial treatment of Philadelphia chromosome–positive chronic-phase chronic myeloid leukemia (Ph+ CP-CML), the Food and Drug Administration announced on Oct. 28.
The approval was based on an open-label, randomized study of the safety and efficacy of dasatinib in patients with CP-CML. The study evaluated gene-based measures of the responses of malignant cells to treatment, according to a statement issued by the FDA.
Myelosuppression, fluid retention, diarrhea, headache, musculoskeletal pain, and rash are among the most common adverse effects associated with treatment, according to the FDA.
Dasatinib, marketed as Sprycel by Bristol-Myers Squibb Co., was first approved in 2006 to treat adults with CP-CML who had resistant disease or who were intolerant to previous treatment, including imatinib (Gleevec). That was an accelerated approval based on early data; the full approval was in 2009, based on 24-month follow-up data from studies confirming that the drug was safe and effective for this indication, according to the FDA.
It is the third drug approved for Ph+ CP-CML through the accelerated approval process, which allows the FDA to approve a drug for a serious disease that has an unmet medical need based on an end point "thought to reasonably predict clinical benefit," according to the statement. A condition of accelerated approval is that the drug’s manufacturer must confirm the benefit of the drug with long-term efficacy and safety data.
In the FDA statement, Dr. Richard Pazdur, director of the Office of Oncology Drug Products in the FDA’s Center for Drug Evaluation and Research, said that the drugs that have received accelerated approval "have dramatically changed the lives of patients with CML." Results from additional CML studies "continue to demonstrate the importance of studying cancer drugs in the earlier stages of a disease," he added.
In some cases, the long-term data show no benefits, and the approval is rescinded. Other FDA-approved treatments for different types of CML include imatinib, approved in 2001, and nilotinib (Tasigna), approved in 2007.