FDA approves Xalkori with companion diagnostic for a type of late-stage lung cancer

FDA approved crizotinib (Xalkori, Pfizer) the first and only therapy specifically for patients with locally advanced or metastatic non-small cell lung cancer (NSCLC) that is anaplastic lymphoma kinase (ALK)-positive as detected by an FDA-approved test.

Xalkori is being approved with a companion diagnostic test that will help determine if a patient has the abnormal ALK gene, a first-of-a-kind genetic test called the Vysis ALK Break Apart FISH Probe Kit. It is the second such targeted therapy approved by FDA this year.

This ALK gene abnormality causes cancer development and growth. About 1% to 7% of those with NSCLC have the ALK gene abnormality. Patients with this form of lung cancer are typically non-smokers. Xalkori works by blocking certain proteins called kinases, including the protein produced by the abnormal ALK gene. Xalkori is a pill taken twice a day as a single-agent treatment.

"The approval of Xalkori with a specific test allows the selection of patients who are more likely to respond to the drug," said Richard Pazdur, MD, director of the Office of Oncology Drug Products in FDA's Center for Drug Evaluation and Research. "Targeted therapies such as Xalkori are important options for treating patients with this disease and may ultimately result in fewer side effects."

Xalkori's safety and effectiveness were established in 2 multicenter, single-arm studies enrolling a total of 255 patients with late-stage ALK-positive NSCLC. A sample of a patient's lung cancer tissue was collected and tested for the ALK gene abnormality prior to study enrollment. The studies were designed to measure objective response rate, the percentage of patients who experienced complete or partial cancer shrinkage. Most patients in the studies had received prior chemotherapy.

In one study, the objective response rate was 50% with a median response duration of 42 weeks. In another, the objective response rate was 61% with a median response duration of 48 weeks.

The FDA based its approval of the Vysis ALK Break Apart FISH Probe Kit on data from 1 of the studies.

Xalkori was reviewed under FDA's priority review program and is being approved under the agency's accelerated approval program. Pfizer is conducting post-marketing clinical trials to further evaluate its clinical benefit.