What PANKU-Breast01 Tested
PANKU-Breast01 is the fourth Phase III readout for iza-bren and its first in HR+/HER2- breast cancer. The trial enrolled patients with unresectable locally advanced, recurrent, or metastatic disease and randomized them between the bispecific ADC and single-agent chemotherapy of physician’s choice — the same comparator design used in the sibling trial PANKU-Breast02 (triple-negative disease). Iza-bren’s dual EGFR×HER3 targeting is designed to block two proliferation and survival signals used by epithelial cancers and to deliver a topoisomerase-I-inhibitor payload after internalization.
Design & Endpoints
Design
Phase III, randomized, open-label, multi-center (China). 383 patients enrolled (actual).
Population
Unresectable locally advanced, recurrent, or metastatic HR+/HER2- breast cancer; adults ≥18.
Interventions
Iza-bren IV (21-day cycles) vs chemotherapy of physician’s choice: eribulin, vinorelbine, gemcitabine, or capecitabine.
Primary Endpoint
Progression-free survival (assessed up to ~24 months). Met at pre-specified interim analysis per the Aug 26, 2026 announcement.
The Topline on X
Iza-bren (Yizekang®) met primary endpoint (PFS) in a pre-specified interim analysis of the PANKU-Breast01 (aka BL-B01D1-306) trial for patients with HR+/HER2- breast cancer. 5th phase III trial to hit the primary endpoint for iza-bren! https://t.co/8MVE3R66aX https://t.co/4bzzeHr7PI
🇨🇳Biokin announced its self-developed EGFR/HER3 bispecific ADC iza-bren (BL-B01D1) has met its primary endpoint of PFS in Phase 3 trial BL-B01D1-306. Indication: unresectable locally advanced, recurrent, or metastatic HR+/HER2- breast cancer, in patients who failed ≥1 prior line of chemotherapy. Per independent Data Monitoring Committee (iDMC) assessment at a pre-specified interim analysis, the PFS endpoint was met. 🔹 5th Phase 3 trial for iza-bren to hit its primary endpoint 🔹 World's first bispecific ADC to reach a Phase 3 primary endpoint in HR+/HER2- breast cancer
🇨🇳Biokin’s Iza-Bren Hits Phase 3 PFS Endpoint in HR+/HER2− Breast Cancer, Marking 5th Phase 3 Success https://t.co/wmSBx7Ortv #BioPharmChina #Oncology #Biology
PANKU-Breast01 Questions
What is the PANKU-Breast01 trial?
PANKU-Breast01 (study code BL-B01D1-306, NCT06343948) is a Phase III, randomized, open-label study in China comparing iza-bren (izalontamab brengitecan) with chemotherapy of physician's choice (eribulin, vinorelbine, gemcitabine, or capecitabine) in patients with unresectable locally advanced, recurrent, or metastatic HR+/HER2- breast cancer. 383 patients were enrolled; the primary endpoint is progression-free survival.
What did the interim analysis show?
On August 26, 2026, Biokin announced that iza-bren met the primary endpoint of progression-free survival at a pre-specified interim analysis. Numeric results (median PFS, hazard ratio, p-value) have not been disclosed; full data are expected at a future medical meeting.
What is iza-bren?
Iza-bren (izalontamab brengitecan, BL-B01D1) is an investigational bispecific antibody-drug conjugate that targets both EGFR and HER3, developed by SystImmune/Biokin and, outside China, jointly with Bristol Myers Squibb. It is not FDA-approved.
Is iza-bren FDA-approved for breast cancer?
No. Iza-bren is investigational in the United States. The FDA has granted Breakthrough Therapy Designation for iza-bren in previously treated EGFR-mutated NSCLC — not in breast cancer.
How does PANKU-Breast01 differ from PANKU-Breast02?
PANKU-Breast01 (BL-B01D1-306) enrolled HR+/HER2- breast cancer and met its PFS endpoint at an interim analysis in August 2026. PANKU-Breast02 (BL-B01D1-307, NCT06382142) enrolled triple-negative breast cancer and reported dual positive PFS and OS results earlier in 2026. They are separate Phase III trials of the same drug.