> ## Content Index
> Fetch the complete content index at: https://www.fdaweb.com/llms.txt
> Use this file to discover other available public pages before exploring further.

# FDA Expands Approval of Pfizer’s Xalkori
- URL: https://www.fdaweb.com/fda-expands-approval-of-pfizers-xalkori/
- Published: 2016-03-11T12:00:00.000Z
- Updated: 2026-09-15T02:43:09.000Z
- Author: David McFarland
- Tags: Drugs, #legacy-id-D5135057

> FDA has given expanded approval to Pfizer’s Xalkori (crizotinib) to treat people with metastatic non-small cell lung cancer (NSCLC) whose tumors have an ROS-1 gene alteration. This gene alteration is present in about 1% of patients with NSCLC. “The overall patient and disease characteristics of NSCLC with ROS-1 gene alterations appear similar to NSCLC with anaplastic lymphoma kinase (ALK) gene alterations, for which crizotinib use was previously approved” in 2011, an [agency release](http://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm490329.htm?ref=fdaweb.com) says. Xalkori works by blocking the activity of the ROS-1 protein in tumors that have ROS-1 gene alterations, it says, adding that this effect “may prevent NSCLC from growing and spreading.”  
>  
> Expanded approval was based on data from a study involving 50 patients with ROS-1 positive metastatic NSCLC. Patients received Xalkori twice daily to measure the drug’s effect on their lung cancer tumors. “Results showed 66% of participants experienced a complete or partial shrinkage of their NSCLC tumors, an effect that lasted a median of 18.3 months,” the agency says.