Pfizer’s Xalkori has picked up a Breakthrough Therapy designation from the US Food and Drug Administration for treating patients with the rare ROS1-positive form of non-small cell lung cancer.

Occurring in around 1% of NSCLC cases, ROS1-positive molecular subgroup is now the second in which Xalkori (crizotinib) “has demonstrated a level of anti-tumour activity that can potentially make a real difference for patients,” noted Mace Rothenberg, chief medical officer for Pfizer Oncology. 

Xalkori is already approved in the US for the treatment of patients with metastatic NSCLC whose tumours are anaplastic lymphoma kinase (ALK)-positive.

Breakthrough designation for the ROS1-positive subgroup indicates that the regulator believes the drug may demonstrate a substantial improvement over existing therapies, based on preliminary clinical evidence.