Iza-bren raises median progression-free survival to 11.1 months in lung cancer trial
Key Facts
A prespecified interim analysis of the PANKU-Lung01 study showed that iza-bren met its primary endpoint, with median progression-free survival of 11.1 months, compared with 5.7 months with platinum-based chemotherapy. The study included 422 patients with EGFR-mutated non-squamous non-small cell lung cancer who had previously received treatment with tyrosine kinase inhibitors targeting the gene. Bristol Myers Squibb and SystImmune announced the results, while the study in China is sponsored by Sichuan Biokin Pharmaceutical, SystImmune’s parent company. The comparison was based on a blinded independent central review, according to the companies’ announcement. The hazard ratio was 0.40, with a 95% confidence interval between 0.31 and 0.51 and a p-value of less than 0.0001. The results were presented in a late-breaking oral session at the European Society for Medical Oncology conference in Madrid on October 26, 2026, alongside publication in The Lancet.
Progression-free survival figures show the difference between the experimental treatment and platinum-based chemotherapy among participants in the interim analysis. Median progression-free survival was 11.1 months in the iza-bren group, compared with 5.7 months in the comparison group. The hazard ratio of 0.40 indicates a relative reduction in the risk of progression or death in the comparison reported by the study. The 95% confidence interval was between 0.31 and 0.51, while the p-value was less than 0.0001. The trial therefore met its stated primary endpoint of progression-free survival. However, this result concerns the study’s primary measure, while the overall survival readout remained immature at the time of the analysis.
The drug recorded a confirmed objective response rate of 60.2%, compared with 34.5% with chemotherapy. Median duration of response was also 10.4 months among patients receiving iza-bren, compared with 5.7 months in the chemotherapy group. These measures add information on tumor response and how long it lasted to the progression-free survival result. However, overall survival data had not matured at the time of the analysis, according to the results announcement. A favorable trend in overall survival was observed for iza-bren, but the announcement did not provide a final result demonstrating an improvement in lifespan. The comparison between the two treatment groups therefore remains based on the interim results available until the overall survival data mature.
The announcement described the safety profile as being dominated by treatment-related adverse events of grade 3 or higher, most of which were hematologic in nature. In the iza-bren group, 1.9% of patients discontinued treatment because of those events. This rate provides one measure of treatment tolerability in the study, alongside response rates and progression-free survival. Under the European Society for Medical Oncology’s Asia-adapted guidelines, acquired resistance with the T790M mutation after first- or second-generation EGFR inhibitors can be treated with platinum-based chemotherapy. The guidelines also encourage enrollment in clinical trials when disease progresses after osimertinib, particularly when a targetable resistance mechanism is identified. This places the comparator chemotherapy among guideline-based options for previously treated patients, while the study is testing an experimental option in this group.
Iza-bren remains an investigational treatment: a bispecific antibody-drug conjugate targeting EGFR and HER3. Meeting the primary endpoint in one study does not mean it has received regulatory approval or that clinical benefit has been established outside the trial. A favorable overall survival trend also does not settle the treatment’s effect on lifespan while the data remain immature. The results were presented at the 2026 European Society for Medical Oncology conference in Madrid, held from October 23 to 27. These interim results provide a comparison of the drug with chemotherapy in patients previously treated with EGFR inhibitors. Overall survival data will continue to be monitored as they mature.