The FDA approved Xalkori (crizotinib) for the treatment of certain cases of late-stage (locally advanced or metastatic), non-small cell lung cancers (NSCLC) expressing the abnormal anaplastic lymphoma kinase (ALK) gene.
Xalkori is being approved with an accompanying 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. This represents the second such targeted therapy approved by the FDA this year.
The ALK gene abnormality is responsible for cancer development and growth, with about 1 to 7% of those with NSCLC having the abnormality. Patients with this form of lung cancer are typically non-smokers. Taken twice daily as a single-agent treatment, the Xalkori pill works by blocking certain proteins (kinases), including the protein produced by the abnormal ALK gene.
Both the safety and effectiveness of Xalkori were established in two multi-center, single-arm studies enrolling a total of 255 patients with late-stage ALK-positive NSCLC. 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; and 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 one of the studies.
Xalkori is being approved under the FDA’s accelerated approval program, which allows the agency to approve a drug to treat a serious disease based on clinical data showing that the drug has an effect on an endpoint that is reasonably likely to predict a clinical benefit to patients. The program is designed to provide patients with earlier access to promising new drugs, followed by further studies to confirm the drug’s clinical benefit.
The most common side effects reported in patients receiving Xalkori included vision disorders, nausea, diarrhea, vomiting, swelling (edema), and constipation. Vision disorders included visual impairment, flashes of light, blurred vision, floaters, double vision, sensitivity to light, and visual field defects. Use of Xalkori has also been associated with inflammation of the lung tissue (pneumonitis), which can be life-threatening. Patients with treatment-related pneumonitis should permanently stop treatment with Xalkori. The drug should not be used in pregnant women.
Xalkori is marketed by New York City-based Pfizer. The Vysis ALK Break Apart FISH Probe Kit is marketed by Abbott Molecular Inc. of Des Plaines, Ill.