DUALITYBIO-B(09606): The research results of the core product DB-1311/BNT324 were presented at the 2026 American Society of Clinical Oncology Genitourinary Cancers Symposium.

DUALITYBIO-B (09606) announced that at the 2026 American Society of Clinical Oncology (ASCO) Genitourinary Cancers Symposium held in San Francisco, United States from February 26 to February 28, 2026, the company will present the latest efficacy and safety results of the phase 1/2 study (DB-1311-O-1001, NCT05914116) of DB-1311/BNT324 (an investigational B7H3 antibody-drug conjugate (ADC)) in the treatment of patients with metastatic castration-resistant prostate cancer (mCRPC) who have previously received extensive therapy, including an analysis based on prior treatment with Lu 177-PSMA-617 (Lu 177). In the dose optimization cohort of this phase 1/2 study, previously treated mCRPC patients received DB1311/BNT324 at a dose of either 6 mg/kg or 9 mg/kg every three weeks (Q3W), while in the dose expansion cohort (mCRPC patients treated with Lu 177 and mCRPC patients who have not received taxane therapy), patients received 6 mg/kg Q3W until disease progression or intolerable toxicity occurred. As of the data cut-off date of September 5, 2025, a total of 104 mCRPC patients had received treatment with DB-1311/BNT324 (including 6 mg/kg, n=68; 9 mg/kg, n=34). The median follow-up time was 9.2 months (range 0.1-19.4), with 52 patients (50%) still receiving treatment. The median age of patients was 70 years (range 45-90 years), with the majority being Caucasian (53%), followed by Asian (31%) and Black (13%) patients. The median number of prior treatments received by patients was 4 (range 1-14). Among the 58 evaluable patients for tumor response assessment (with measurable lesions according to RECIST 1.1 at baseline), the unconfirmed objective response rate was 41.4% (95% CI 28.6-55.1), the confirmed objective response rate (cORR) was 34.5%, and the disease control rate (DCR) was 87.9% (95% CI 76.7-95.0). The median duration of response (DOR) was 10.2 months (95% CI 7.2, NE). In the 82 evaluable patients for radiographic progression-free survival (rPFS), the median rPFS was 11.3 months (95% CI 7.2, NE), with rPFS rates at 6 months and 9 months being 72.0% and 63.0%, respectively. As of the data cut-off date, overall survival (OS) data were still immature, with OS rates at 6 months and 9 months being 91.7% and 88.2%, respectively. The PSA50 response rate was 35.4%, with a median PSA DOR of 8.4 months (95% CI 4.4, NE). Safety data were consistent with the company's previous report at the 2025 ASCO conference. The most common adverse events were nausea and hematological events, mostly grade 1-2. Among the 34 patients (33%) who had previously received Lu 177 therapy, the median age was 69 years (range 55-84 years), with a ratio of Caucasian/Asian/Black patients at 65%/15%/15%. The median number of prior treatments received was 5 (range 2-14), and 24 patients (71%) were still receiving treatment. The results were similar between patients who had and had not received Lu 177 treatment, but patients who had previously received Lu 177 had a shorter PSA DOR.