ABBISKO-B (02256) announced on December 8, 2025, that Shanghai Abbisko Biotechnology Co., Ltd. (Abbisko) presented positive preliminary results from the dose-escalation phase of its Phase II clinical study (ABSK043-202) evaluating the combination of its investigational oral small-molecule PD-L1 inhibitor ABSK043 with Furmonertinib, a third-generation EGFR-TKI developed by Shanghai Allist Pharmaceuticals, for the treatment of non-small cell lung cancer (NSCLC) at the European Society for Medical Oncology Asia Congress 2025 (ESMO Asia 2025).

The data demonstrated that the "targeted-immunotherapy" combination of ABSK043 and Furmonertinib exhibited favorable safety and tolerability. Based on the promising safety profile, regulatory authorities approved expanding the study to evaluate the regimen as a first-line treatment for EGFR-mutated, PD-L1-positive NSCLC patients.

EGFR mutations are the most common oncogenic driver mutations in NSCLC. While third-generation EGFR-TKIs have become the standard first-line treatment for advanced EGFR-mutated NSCLC, studies indicate that patients with high PD-L1 expression derive less benefit from EGFR-TKIs compared to those with low or negative PD-L1 expression. Additionally, although immunotherapy has shown remarkable efficacy in multiple cancers, combining PD-1/PD-L1 antibodies with EGFR-TKIs has been limited by severe toxicities, leaving unmet clinical needs for this patient population.

At ESMO Asia 2025, Professor Shun Lu from Shanghai Chest Hospital, affiliated with Shanghai Jiao Tong University School of Medicine, presented the positive dose-escalation results of the ongoing Phase II study (ABSK043-202) in a poster session. The dose-escalation phase enrolled 21 EGFR-mutated, PD-L1-positive advanced NSCLC patients, 17 of whom had previously received third-generation EGFR-TKIs.

Results showed that ABSK043 combined with Furmonertinib demonstrated manageable safety and good tolerability. No dose-limiting toxicities (DLTs) or interstitial lung disease (ILD) were observed as of the data cutoff. The most common treatment-emergent adverse events (TEAEs) were Grade 1-2, with no Grade 4 or 5 TEAEs reported.

The combination also exhibited encouraging antitumor activity. The disease control rate (DCR) assessed by RECIST v1.1 was 71%, with 14 patients achieving target lesion shrinkage. Among the five patients who achieved partial response (PR), four had prior third-generation EGFR-TKI treatment. The median duration of response (DOR) had not yet been reached at the time of analysis.

The dose-escalation findings suggest that ABSK043 plus Furmonertinib not only has a manageable safety profile but also shows promising preliminary antitumor activity. This innovative oral "targeted-immunotherapy" strategy may overcome the toxicity challenges historically associated with combining EGFR-TKIs and immunotherapy antibodies.

These positive results lay the foundation for the ongoing dose-expansion phase, which will evaluate ABSK043 combined with Furmonertinib as a first-line therapy for treatment-naïve EGFR-mutated, PD-L1-positive NSCLC patients.