US patients with ROS-1 positive non-small cell lung cancer (NSCLC) will no doubt welcome news that regulators have approved the first treatment for the condition, after expanding the scope of Pfizer’s Xalkori.

Xalkori (crizotinib) is a kinase inhibitor already on the US for the treatment of patients with NSCLC whose tumours are anaplastic lymphoma kinase (ALK)-positive as detected by an approved test.

Now, the US Food and Drug Administration has also cleared its use for people with advanced NSCLC whose tumours have an ROS-1 gene alteration, thought to be present in around 1% of cases.

“Lung cancer is difficult to treat, in part, because patients have different mutations, some of which are rare,” noted Richard Pazdur, director of the Office of Haematology and Oncology Products in the FDA’s Center for Drug Evaluation and Research. 

“The expanded use of Xalkori will provide a valuable treatment option for patients with the rare and difficult to treat ROS-1 gene mutation by giving health care practitioners a more personalized way of targeting ROS-1 positive NSCLC.”

The FDA’s decision comes on the back of clinical data showing that 66 percent of patients taking the drug experienced a complete or partial shrinkage of their NSCLC tumours, and that this effect that lasted a median of 18.3 months.

The most common side effects were found to be vision disorders, nausea, diarrhoea, vomiting, swelling, constipation, liver problems, fatigue, decreased appetite, upper respiratory infection, and dizziness and numbness or tingling in the hands or feet, but the regulator also noted that Xalkori can cause serious side effects such as life-threatening or fatal inflammation of the lungs and abnormal heartbeats.

“As the only FDA-approved biomarker-driven therapy that includes two distinct molecular targets in metastatic NSCLC, ROS1 and ALK, Xalkori exemplifies our commitment to precision drug development and to identifying the right treatment for the right patient,” noted Mace Rothenberg, Pfizer Oncology’s chief medical officer.

The European Medicines Agency is also currently considering the Xalkori’s use in this patient population.