Here is a polished English translation of the Chinese title: **”TYK Medicine’s Atatinib Debuts at ASCO: Domestic EGFR-TKI Achieves Milestone Breakthrough in Tackling Lung Cancer Brain Metastases”**

Hong Kong, Shanghai, and HuzhouJune 4, 2026 /PRNewswire/ — On May 31, 2026, Beijing time, the 2026 American Society of Clinical Oncology (ASCO) Annual Meeting, a premier global oncology event, grandly opened in Chicago. The interim analysis results of the pivotal Phase II ESAONA study, comparing the self-developed oral EGFR-TKI Edotinib Mesylate (TY-9591) by Hong Kong-listed innovative drug company TYK Medicines (02410.HK) against Osimertinib as a first-line treatment for EGFR-mutated non-small cell lung cancer (NSCLC) patients with brain metastases, were presented as a Late-Breaking Abstract (LBA) oral report at this ASCO. The study results showed that Edotinib demonstrated significant advantages in both intracranial efficacy and systemic antitumor activity, with benefits observed across all subgroups, indicating best-in-class therapeutic potential.

The clinical data of Edotinib quickly garnered high attention from oncology experts, the pharmaceutical industry, and capital markets both domestically and internationally. This achievement not only marks a milestone leap for domestic innovative drugs in the challenging field of lung cancer brain metastasis treatment, further highlighting the innovation capabilities of domestic pharmaceutical companies, but also brings a new treatment pathway for NSCLC patients with brain metastases.

Superior Efficacy in Both Intracranial and Systemic Outcomes, Demonstrating Best-in-Class Potential

The ESAONA study released at ASCO is an open-label, multicenter, randomized controlled pivotal Phase II clinical trial. Using the global first-line standard therapy Osimertinib as a comparator, it aims to comprehensively verify the efficacy and safety of Edotinib as a first-line treatment for NSCLC patients with brain metastases harboring classic EGFR mutations. The study was led by Professor Shi Yuankai from the Cancer Hospital of the Chinese Academy of Medical Sciences, with participation from over 50 research centers nationwide.

As of December 15, 2025 (the data cutoff date for this analysis), a total of 224 subjects were enrolled, with 111 in the Edotinib group and 113 in the Osimertinib group. They received Edotinib 160 mg once daily or Osimertinib 80 mg once daily, respectively, and were stratified by EGFR mutation subtype (19Del or L858R) and number of intracranial lesions (>3 or ≤3) to ensure balanced and comparable baseline data between the two groups. The study used Blinded Independent Central Review (BICR)-assessed intracranial objective response rate (iORR) and intracranial progression-free survival (iPFS) as primary endpoints, conducting a comprehensive evaluation across multiple dimensions including intracranial efficacy, systemic antitumor activity, and safety.

Interim analysis data showed that at a median follow-up of 19.12 months, regarding the most closely watched intracranial efficacy, authoritative BICR assessment revealed that the intracranial objective response rate was 95.5% in the Edotinib group and 79.6% in the Osimertinib group, with highly significant statistical difference (P=0.0004). This significant benefit was observed across all predefined subgroups, with all subgroups defined by the prespecified stratification factors benefiting from Edotinib treatment.

In terms of long-term intracranial survival benefits, the median intracranial progression-free survival (iPFS) was not reached in the Edotinib group, while it was 17.51 months in the Osimertinib group, with a hazard ratio (HR) of 0.46 (P=0.0020). Furthermore, long-term follow-up data showed that the 18-month and 24-month iPFS rates in the Edotinib group were 75.24% and 61.56%, respectively, significantly higher than the 48.12% and 38.28% in the control group, indicating that Edotinib effectively reduced the risk of intracranial disease progression. Additionally, the median duration of intracranial response was also not reached for Edotinib, compared to 16.26 months for Osimertinib.

From the perspective of systemic antitumor efficacy, BICR assessment showed that the overall objective response rate (ORR) was 89.2% in the Edotinib group, compared to 77.9% in the Osimertinib group (P=0.0301); median progression-free survival was not reached, showing a clear advantage over the control group’s 17.22 months (HR=0.64, P=0.0473). This also implies that Edotinib can effectively delay systemic tumor progression, offering patients a longer survival period. Overall survival data are not yet mature, and follow-up is ongoing.

For the clinical implementation of innovative antitumor drugs, both efficacy and safety are indispensable. In terms of safety, the overall safety profile of Edotinib was manageable and tolerable. The incidence of treatment-emergent adverse events was similar between the two groups. Although the incidence of Grade 3 or higher adverse events was 49.5% in the Edotinib group, most adverse reactions were mild to moderate and could be effectively managed with symptomatic intervention and dose adjustments.

In summary, the ESAONA head-to-head superiority study has broken through the limitations of previous clinical explorations of EGFR-TKIs in brain metastases. With conclusive clinical data, it demonstrates that a new-generation drug has the potential to reshape the evaluation benchmark for first-line targeted therapy of EGFR-mutated brain metastases, providing high-level evidence from China for global research and development of similar drugs and optimization of clinical regimens.

New Drug Application Accelerates, Innovative Formulation Poised to Reshape Clinical Landscape of Lung Cancer Brain Metastases

EGFR mutation is the most common driver mutation in advanced non-small cell lung cancer. Brain metastases, as the most aggressive form of lung cancer spread, not only significantly shorten patient survival but also severely impair quality of life, posing a persistent clinical challenge.

While current mainstream third-generation EGFR-TKIs can effectively control systemic tumor lesions, their inhibitory effect on intracranial metastases remains limited due to insufficient blood-brain barrier penetration. This efficacy gap fails to meet critical clinical needs, and there is an urgent clinical demand for a new-generation therapeutic agent with stronger intracranial efficacy and better safety tolerability.

As an innovative drug company deeply engaged in the field of tumor kinase inhibitors, TYK Medicines, since its establishment in 2017, has consistently focused on unmet clinical needs, building a pipeline of over ten innovative drug candidates covering the entire R&D cycle from preclinical studies to Phase III clinical trials. Edotinib is a new-generation, highly selective, irreversible oral EGFR-TKI developed in-house by TYK Medicines, and it is a differentiated deuterated innovative drug based on Osimertinib. Through unique molecular structure optimization, Edotinib exhibits superior pharmacokinetic characteristics, significantly reducing the generation of toxic metabolites. Early clinical studies have already demonstrated its potent intracranial lesion inhibitory ability and good safety tolerability, laying a solid foundation for the high-quality data readout from the ESAONA study.

Based on the excellent data from ESAONA, TYK Medicines submitted a New Drug Application (NDA) for Edotinib to the Center for Drug Evaluation of the National Medical Products Administration in February this year, which has been accepted. This is a new-generation EGFR-TKI inhibitor filed for approval with lung cancer brain metastases as the target indication, and it has been included in the priority review and approval process, potentially accelerating its path to market. Once approved, Edotinib will fill the demand for upgraded precision treatment of lung cancer brain metastases in China, offering a new treatment option for patients with advanced lung cancer.