TYK Medicines (02410.HK) released interim results from the pivotal Phase II ESAONA study comparing asandeutertinib (TY-9591) with osimertinib as first-line therapy for epidermal growth factor receptor (EGFR)-mutant non-small cell lung cancer (NSCLC) patients with brain metastases. Findings were presented as a late-breaking abstract at the 2026 American Society of Clinical Oncology annual meeting.

The open-label, multicentre trial randomised 224 untreated patients 1:1 to receive asandeutertinib 160 mg once daily or osimertinib 80 mg once daily. Primary endpoints were intracranial objective response rate (iORR) and intracranial progression-free survival (iPFS) assessed by blinded independent central review (BICR).

Key intracranial efficacy data: • BICR-confirmed iORR reached 95.50 % for asandeutertinib versus 79.60 % for osimertinib, yielding a 15.62 % difference (95 % CI: 6.66 %–24.34 %; P = 0.0004). • Median BICR-iPFS was not reached in the asandeutertinib arm and 17.51 months in the comparator arm (HR = 0.46; 95 % CI: 0.28–0.76; P = 0.0020). Eighteen- and 24-month iPFS rates were 75.24 % and 61.56 % for asandeutertinib versus 48.12 % and 38.28 % for osimertinib, respectively. • Investigator-assessed analyses confirmed the intracranial advantage, with iORR of 92.80 % versus 77.90 % (P = 0.0019) and median iPFS not reached versus 17.51 months (HR = 0.56; P = 0.0122).

Systemic efficacy also favoured asandeutertinib: BICR-confirmed overall response rate was 89.20 % versus 77.90 % (P = 0.0301), and median progression-free survival was not reached versus 17.22 months (HR = 0.64; P = 0.0473). Overall survival data remain immature.

Safety profiles were manageable. Treatment-emergent adverse events (TEAEs) occurred in 100 % of asandeutertinib recipients and 99.10 % of osimertinib recipients. Grade ≥3 TEAEs were reported in 49.50 % and 21.20 % of patients, respectively, with four permanent discontinuations due to treatment-related events in each group. Most high-grade events resolved after symptomatic management or dose reduction.

The New Drug Application for asandeutertinib has been accepted by China’s Center for Drug Evaluation and granted priority review. Progression-free survival and overall survival follow-up continues, alongside additional monotherapy and combination studies in China.

Investors are reminded that successful development and commercialisation are not guaranteed, in line with Rule 18A.05 disclosure requirements.