The US Food and Drug Administration (FDA) has granted breakthrough therapy designation to Nuvalent Inc’s NVL-520 for the treatment of patients with ROS1-positive metastatic non-small cell lung cancer who have been previously treated with two or more  ROS1 tyrosine kinase inhibitors (TKIs).

ROS1 rearrangements occur in up to approximately 3% of metastatic non-small cell lung cancers. At the time of diagnosis, up to 40% of these patients present with accompanying brain metastases, and approximately 40% of patients develop resistance mutations following current front-line treatment. There remains no clear standard of care for patients who have been previously treated with two or more ROS1 TKIs.

NVL-520 is a novel brain-penetrant ROS1-selective TKI created with the aim to simultaneously overcome the clinical challenges of emergent treatment resistance, brain metastases, and off-target central nervous system adverse events associated with inhibition of the structurally-related tropomyosin receptor kinase (TRK) family that may limit the use of currently available ROS1 TKIs.

Breakthrough therapy designation is designed to expedite the development and review of therapies intended to treat a serious or life-threatening condition and whose preliminary clinical evidence indicates that the drug may demonstrate substantial improvement on one or more clinically significant endpoints over existing available therapies. Under the designation, the FDA provides intensive guidance, organizational commitment involving senior managers, and eligibility for rolling review and other actions to expedite review.

The breakthrough therapy designation for NVL-520 is based on the preliminary safety and activity of NVL-520 in heavily pretreated patients with advanced ROS1-positive non-small cell lung cancer in the phase 1 portion of the phase 1/2 ARROS-1 clinical trial. Enrollment in the phase 2 portion of the trial is ongoing, and the company expects to share updated data from the trial at a medical meeting in 2024.