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Lung cancer remains the leading cause of cancer death worldwide, and non-small cell lung cancer, known as NSCLC, accounts for roughly 80% to 85% of lung cancer cases diagnosed each year (American Cancer Society). Unlike the small cell form of the disease, NSCLC tends to grow more slowly and is divided into subtypes such as adenocarcinoma, squamous cell carcinoma and large cell carcinoma, each starting from a different lung cell type but grouped together because treatment approaches are often similar. In the United States alone, the American Cancer Society projects more than 229,000 new lung cancer cases in 2026 and close to 125,000 deaths, making it the leading cause of cancer death in both men and women.
Within this broad category, researchers have identified specific genetic alterations that drive tumor growth in smaller subsets of patients. One of these is a rearrangement involving the ROS1 gene, found in an estimated 50,000 people worldwide each year. Patients with ROS1-positive NSCLC often look different from the typical lung cancer patient, since many are diagnosed in their 40s or 50s with little to no history of smoking, unlike most other forms of the disease. The disease also tends to spread into the brain and central nervous system as it progresses, adding another layer of difficulty to an already serious diagnosis and complicating long term treatment decisions.
Targeted therapies for ROS1-positive NSCLC have existed for a number of years now, but they still carry real limitations. Tumors can develop resistance mutations that let cancer cells keep growing despite ongoing treatment, and not every existing drug crosses the blood brain barrier well enough to control disease that reaches the brain. Long term tolerability is also a real concern, since side effects can build up gradually over months or years of continuous therapy. Because people with this mutation are often diagnosed young and may live with the disease for years, doctors and patients have been looking for options that combine strong efficacy with a manageable safety profile, something the field has pursued for some time (GSK news release).
That search moved forward this week. GSK plc (NYSE: GSK) announced that the U.S. Food and Drug Administration has approved Jideytro (zidesamtinib), a ROS1 selective inhibitor, for adults with locally advanced or metastatic ROS1-positive NSCLC previously treated with a ROS1 kinase inhibitor. The clearance arrived nearly two months ahead of its original target date of September 18, 2026, following earlier Breakthrough Therapy and Orphan Drug designations.
The drug was built with specific goals: strong ROS1 selectivity, coverage of resistance mutations, and the ability to cross into the brain. Approval rests on the ARROS-1 phase I/II trial, a global single arm study of 117 patients previously treated with a ROS1 inhibitor. The objective response rate reached 44%, and responses held up over time, with 82% of responders still responding at six months and 69% at 12 months. Among a broader safety group of 446 patients, common side effects included swelling, nerve pain, constipation, fatigue and shortness of breath.
GSK chief scientific officer Tony Wood pointed to the pace of approval as evidence of strong science and unmet need. Alexander Drilon, an ARROS-1 investigator at Memorial Sloan Kettering Cancer Center, said responses among heavily pretreated patients marked real progress. Janet Freeman-Daily, co-founder of the patient group The ROS1ders, said patients want quality time living as normally as possible, not just more time.
Jideytro is GSK’s first approved lung cancer medicine, arriving after its recently completed acquisition of Nuvalent, Inc. That deal also brought neladalkib, an ALK altered NSCLC treatment under FDA review with a target decision date of November 27, 2026, and NVL-330, an early stage HER2 altered program. GSK is also developing risvutatug rezetecan, a B7-H3 antibody drug conjugate with positive phase III results in relapsed small cell lung cancer, licensed from Hansoh Pharma Inc.
A company built mainly around blood cancers and cancers affecting women is now entering lung cancer for the first time. What happens next depends on how the rest of the Nuvalent pipeline performs, and how Jideytro holds up once it moves from a controlled trial into everyday practice.
