Xalkori® is a targeted therapy that is used to treat some non-small cell lung cancers (NSCLC) that have a certain anaplastic lymphoma kinase (ALK) or ROS1 mutation. ALK or ROS1 mutation is determined by biomarker tests (molecular testing) conducted on a biopsy sample of the tumor. Crizotinib is an ALK inhibitor and is also classified as a kinase inhibitor. It is designed to block the activating sites (tyrosine kinases) of several proteins within the cancer cell. These proteins can stimulate cancer growth when the tumor has an ALK or ROS1 mutation. By blocking the proteins, crizotinib may shrink the cancer or slow the cancer’s progression.1,2
Crizotinib is used to treat patients with NSCLC that has a certain ALK or ROS1 gene mutation and has spread to other parts of the body (metastasized).1 It may also be used to treat certain forms of anaplastic large cell lymphoma.
About ALK mutations
An estimated 3-5 percent of lung tumors have mutations on the ALK gene, which stands for anaplastic lymphoma kinase. ALK mutations are more common in light smokers (may be defined as less than 10 pack years*) and/or never-smokers (patients may be considered “never smokers” if they have smoked less than 100 cigarettes in their lifetime). These mutations are also associated with younger patient age and adenocarcinomas.4,5
Crizotinib is a capsule taken by mouth. The dosage is determined by several factors, including the patient’s general health, liver and kidney function, and ongoing response to treatment. Patients should not drink grapefruit juice or eat grapefruit during treatment with crizotinib, as it may increase the level of crizotinib in the blood to a harmful level. Patients should take their medication as prescribed by their doctor. Patients should talk to their doctor if they have any questions, or if they have questions regarding their crizotinib regimen.2
Side effects of crizotinib
Crizotinib may cause side effects, and in some cases, these side effects can be severe. Any side effects should be reported to a health care professional. Side effects experienced in greater than approximately 30 percent of patients taking crizotinib include vision problems (such as blurred vision, double vision, or increased sensitivity to light), nausea, diarrhea, and vomiting. Less common side effects experienced in approximately 10-29 percent of patients receiving Xalkori include swelling (edema), constipation, fatigue, decreased appetite, dizziness, increased liver enzymes, numbness or tingling in hands and feet, taste changes, heartburn, and rash. Rarely, crizotinib can cause severe side effects, and patients taking crizotinib should seek medical care immediately if they experience difficulty breathing with a cough or fever, slow or fast heartbeat, or dizziness. Additional side effects that are not an emergency but require medical attention include frequent diarrhea (4-6 episodes within 24 hours), nausea, vomiting (more than 4-5 times within 24 hours), signs of dehydration (tiredness, dry mouth, dark and decreased urine, or dizziness), eye irritation, yellowing of the skin or whites of the eyes (jaundice), dark or brown urine, decreased appetite, pain on the right side of the stomach region, bleeding or bruising more than normal, itching, or coughing with or without mucus. This is not an exhaustive list of all potential side effects of crizotinib. Talk to your healthcare provider or pharmacist for further information.1,2
Patients receiving crizotinib should talk to their doctor about any other medications (prescription and over-the-counter), herbal remedies, and any supplements they are taking, as well as any other health conditions. If you are pregnant, plan to become pregnant, or are breastfeeding or plan to breastfeed, talk with your doctor. Crizotinib can cause harm to a developing fetus and should not be taken by women who are pregnant. While taking crizotinib, males with female partners who can become pregnant, and females who can become pregnant, should both use contraceptives during treatment and for a period of time after completing treatment (patients should discuss appropriate birth control methods, and how long they need to use them, with their doctor). Females should not breastfeed during crizotinib treatment and for a period of time following the final dose (patients should discuss breastfeeding considerations with their doctor).2
*Pack years is a term used to help quantify the equivalent of how many years a patient has smoked. It is calculated by multiplying the number of packs of cigarettes smoked per day by the number of years the person has smoked. For example, smoking one pack per day for one year equals 1 pack year, whereas smoking two packs per day for two years equals 4 pack years.