GSK’s Jideytro Shows 94% Response in ROS1 Lung Cancer

London, United Kingdom, September 13, 2026

ARROS-1 Demonstrates High Response Rates

The registrational analysis included 94 efficacy-evaluable TKI-naïve patients with measurable disease. Treatment with zidesamtinib produced an objective response rate of 94%, with 88 of 94 patients responding and a 15% complete response rate. Responses appeared durable, with 94% of responding patients continuing to respond at nine months and 86% maintaining responses at 12 months. The 12-month progression-free survival rate was 90%, while median progression-free survival and median duration of response had not yet been reached at the time of analysis. These findings provide clinical support for further regulatory evaluation of zidesamtinib as a potential first-line targeted therapy for ROS1-positive NSCLC. The study also generated encouraging findings in patients with central nervous system disease, an important consideration in ROS1-positive lung cancer because the disease has a high propensity to spread to the brain. All 10 patients with measurable brain metastases at baseline responded to zidesamtinib, while 70% achieved complete clearance of detectable brain tumors. At 12 months, 78% of these patients maintained an intracranial response. No CNS progression events were observed among patients who did not have brain metastases at baseline, further supporting continued evaluation of the therapy’s activity against disease involving the central nervous system.

Jideytro Targets ROS1-Positive NSCLC

Zidesamtinib is an oral, next-generation ROS1 tyrosine kinase inhibitor designed to provide broad coverage of ROS1 resistance mutations while maintaining activity against tumors that have spread to the brain. ROS1 alterations occur in approximately 2% of NSCLC cases and are associated with a particular need for effective targeted treatments because patients can develop acquired resistance and CNS progression during therapy. The ARROS-1 program evaluated zidesamtinib across multiple treatment settings. Of the 532 patients with ROS1-positive NSCLC who received zidesamtinib 100 mg once daily across the broader program, 183 were receiving their first ROS1-targeted TKI treatment. The current analysis specifically focused on the 94 patients with measurable disease who initiated treatment by June 15, 2025, allowing at least nine months of follow-up for assessment of response durability. Some patients had previously received chemotherapy or immunotherapy, although they had not received a prior ROS1 TKI.

Safety and Regulatory Expansion

The efficacy findings were accompanied by a generally manageable safety profile. The most common treatment-related adverse events occurring in at least 15% of patients included peripheral oedema, weight increase, elevated blood creatine phosphokinase, dysgeusia and increased aspartate aminotransferase. Most events were low grade. Treatment-related adverse events led to dose reductions in 11% of patients and treatment discontinuation in only 1%, supporting continued evaluation of zidesamtinib for long-term treatment. GSK plans to use the ARROS-1 findings to support a U.S. regulatory submission in 2026 for first-line use. However, Jideytro is not currently approved for first-line ROS1-positive NSCLC, and the new indication remains subject to regulatory review. The therapy received U.S. approval in July 2026 for patients with locally advanced or metastatic ROS1-positive NSCLC previously treated with a ROS1 TKI. The latest data represent an important milestone in targeted oncology drug development, particularly for patients who require durable disease control while managing the risk of brain metastases and treatment-related toxicity. If the planned regulatory application is successful, zidesamtinib could potentially expand the treatment options available for patients with previously untreated ROS1-positive advanced NSCLC.

Source: GSK press release