On August 27, 2026, Hong Kong-listed innovative drug developer TYK Medicines-B (02410) announced that its independently developed Class 1 new drug, Dutersatinib mesylate tablets (TY-9591), received conditional marketing approval from China's National Medical Products Administration (NMPA). The approval covers first-line treatment for adult patients with locally advanced or metastatic non-small cell lung cancer (NSCLC) harboring epidermal growth factor receptor (EGFR) exon 19 deletions (19DEL) or exon 21 (L858R) substitution mutations, along with central nervous system (CNS) metastases.
This approval introduces a novel domestic targeted therapy option for a clinically challenging patient population, marking a significant breakthrough for China's next-generation EGFR-TKI development. The registration was supported by robust clinical evidence from the pivotal ESAONA study, demonstrating notable differentiation in intracranial efficacy.
Pivotal study reinforces clinical evidence with intracranial efficacy advantages
The approval is based on data from ESAONA, an open-label, multicenter, randomized controlled Phase II pivotal trial. Interim analysis results were presented as a Late-Breaking Abstract (LBA) oral report at the 2026 ASCO Annual Meeting, drawing significant attention from the global oncology community. The study enrolled 224 patients, randomized 1:1 to receive either Dutersatinib (160mg QD) or Osimertinib (80mg QD), with stratification by EGFR mutation subtype and number of intracranial lesions to ensure balanced baseline characteristics between groups. The primary endpoints were blinded independent central review (BICR)-assessed intracranial objective response rate (iORR) and intracranial progression-free survival (iPFS).
As of December 15, 2025, the median follow-up duration was 19.12 months. BICR results showed that the Dutersatinib group achieved an iORR of 95.5%, significantly surpassing the control group's 79.6% (P=0.0004). The median iPFS had not yet been reached in the Dutersatinib arm, representing a significant prolongation compared to the Osimertinib group's median iPFS of 17.51 months (HR=0.46, P=0.0020). Furthermore, the 18-month and 24-month iPFS rates for the Dutersatinib group were 75.24% and 61.56%, respectively, both significantly higher than the control group, with consistent benefits observed across all predefined subgroups.
From a systemic antitumor efficacy perspective, BICR assessments indicated an objective response rate (ORR) of 89.2% for the Dutersatinib group, compared to 77.9% for the control group (P=0.0301). While the progression-free survival (PFS) data were not yet mature, the median PFS for the Dutersatinib group was not reached, outperforming the Osimertinib group's 17.22 months (HR=0.64, P=0.0473). Overall survival (OS) data were also immature; as of June 10, 2026, with a median follow-up of 15.8 months, 69 events (30.8% maturity) had occurred, yielding a hazard ratio of 0.779 (P=0.3023) for Dutersatinib versus Osimertinib. In terms of safety, Dutersatinib demonstrated a manageable overall safety profile, with most grade 3 or higher adverse events effectively resolved through symptomatic treatment and dose adjustments.
Addressing unmet clinical needs and advancing domestic targeted therapy value
EGFR mutations represent the most common driver mutation type in NSCLC, while brain metastasis poses the most formidable metastatic challenge in advanced disease, severely impacting patient survival and quality of life. Although current third-generation EGFR-TKIs have substantially improved overall survival for EGFR-mutant lung cancer patients, their limited blood-brain barrier penetration remains a shortfall in effectively controlling intracranial lesions, leaving significant unmet clinical needs. Dutersatinib, developed by TYK Medicines-B, is a next-generation highly selective, irreversible oral EGFR-TKI and a deuterated derivative of Osimertinib. Through molecular structural optimization, its pharmacokinetic profile is enhanced with reduced production of toxic metabolites, offering distinct clinical advantages, particularly for EGFR 19del and L858R sensitive mutation lung cancer patients with brain metastases. The company continues to advance multiple monotherapy and combination therapy clinical explorations to further unlock the drug's therapeutic potential.
TYK Medicines-B stated that the successful approval of Dutersatinib mesylate tablets represents a pivotal milestone in transitioning from clinical development to commercialization, validating its innovative R&D capabilities and marking solid progress in overcoming lung cancer treatment bottlenecks. Moving forward, the company remains committed to a long-term strategy, intensifying efforts in original innovation and combination therapy research to build a more competitive oncology product portfolio, contributing to the "Healthy China" initiative and ensuring that domestically developed innovative therapies genuinely benefit patients.