On October 19, 2025 SystImmune Inc. (SystImmune), a clinical-stage biotechnology company, reported positive topline results from the BL-B01D1-301 trial. The trial has met one of the dual primary endpoints (BICR-assessed ORR) as iza-bren has demonstrated a statistically significant and clinically meaningful improvement in BICR-assessed ORR in recurrent or metastatic NPC patients who had progressed after at least two prior lines of chemotherapy, including platinum-based chemotherapy and a PD-1/PD-L1 inhibitor. These results were presented today in a late-breaking oral presentation at the 2025 European Society of Medical Oncology (ESMO) (Free ESMO Whitepaper) Congress.

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Iza-bren is a potentially first-in-class topoisomerase 1 inhibitor-based bispecific antibody-drug conjugate (ADC) which targets both epidermal growth factor receptor and human epidermal growth factor receptor 3 (EGFRxHER3). It is being developed by Biokin in China and jointly developed by SystImmune and Bristol Myers Squibb under a collaboration and exclusive license agreement in territories outside of China.

Iza-bren has shown a BICR-assessed ORR of 54.6% vs. 27.0% (Odds Ratio 3.3; 95% confidence interval 1.9-5.8; p<0.0001). Median duration of response (DoR) was 8.5 months for iza-bren versus 4.8 months for physician’s choice of chemotherapy (Hazard ratio 0.43; 95% CI 0.22 to 0.83). Furthermore, median progression-free survival (PFS) was 8.38 months with iza-bren compared to 4.34 months for chemotherapy (hazard ratio of 0.44; 95% confidence interval 0.32-0.62). The ORR and PFS benefits were consistent across all subgroup analysis. At the time of this analysis, the overall survival (OS) data were immature.

Iza-bren was well-tolerated with a manageable safety profile. The most common adverse events were hematological toxicities, which were effectively managed with standard supportive care. Two patients in the iza-bren arm experienced Grade 2 interstitial lung disease (ILD), whereas two patients in the chemotherapy arm experienced Grade 3 ILD. The safety profile in the BL-B01D1-303 study was consistent with the known profiles of the therapy with no new safety signals identified.

"The positive topline results from the first registrational trial of iza-bren presented at ESMO (Free ESMO Whitepaper) demonstrated clear clinical benefits of iza-bren compared to traditional chemotherapy. These data add to the growing body of clinical evidence that continues to reinforce our confidence in iza-bren’s mechanism of action and therapeutic potential. We believe iza-bren can deliver clinically meaningful benefit by targeting key cancer biological pathways to improve outcomes for patients across a broad range of advanced malignancies," added Dr. Jonathan Cheng, Chief Medical Officer of SystImmune.

The New Drug Application (NDA) for iza-bren for the treatment of recurrent or metastatic nasopharyngeal carcinoma (NPC) has been submitted by Biokin to the Center for Drug Evaluation (CDE) of the China National Medical Products Administration (NMPA) in China.

About BL-B01D1-303

BL-B01D1-303 is a phase III, randomized, open-label, multicenter study in China to evaluate the efficacy and safety of BL-B01D1 in patients with recurrent or metastatic nasopharyngeal carcinoma who have failed PD-1/PD-L1 monoclonal antibody and at least two lines chemotherapy (one line must contain platinum-based chemotherapy). For more detailed information, please visit clinical.trials.gov (NCT06118333).

About Nasopharyngeal Carcinoma (NPC)

Nasopharyngeal Carcinoma (NPC) is a type of head and neck cancer that originates in the nose. NPC is uncommon globally, but is endemic in southern China, southeast Asia and parts of Africa, and is rising among the immigrant population in US and Europe. NPC is strongly associated with EBV infection. There is a significant unmet need as 5-year overall survival rate is generally less than 10% in the later line metastatic setting.

About iza-bren

SystImmune, in collaboration with BMS outside of China, is developing iza-bren (BL-B01D1), a bispecific antibody-drug conjugate (ADC) that targets both EGFR and HER3, which are highly expressed in various epithelial cancers and are known to be associated with cancer cell proliferation and survival. Iza-bren’s dual mechanism of action blocks EGFR and HER3 signals to cancer cells, reducing proliferation and survival signals. In addition, upon antibody mediated internalization, iza-bren’s therapeutic novel Topo1i payload is released causing cytotoxic stress that leads to cancer cell death.

(Press release, SystImmune, OCT 19, 2025, View Source [SID1234656797])