SHANGHAI, China– Dec. 18, 2025 – Duality Biotherapeutics (“DualityBio”, HKEX:09606)

announced that the U.S. Food and Drug Administration (FDA) has granted Fast Track Designation (FTD) to its next-generation HER3-targeting antibody-drug conjugate (ADC) DB-1310. The designation is for the treatment of adult patients with advanced/unresectable or metastatic hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2) negative (IHC 0, IHC 1+ or IHC 2+/ISH-) breast cancer who have received prior endocrine-based therapy, CDK4/6 inhibitor, with or without chemotherapy for unresectable or metastatic disease, or developed disease recurrence during or within 6 months of completing adjuvant chemotherapy. 

DB-1310 is the first HER3-ADC to receive FTD in this indication globally.

The granted FTD covers a broad patient population with HR+/HER2- breast cancer, including those “with or without prior chemotherapy” in advanced/unresectable or metastatic stage. The FTD of such a broad indication is expected to facilitate the pivotal clinical development of DB-1310 in two dominant pathways of HR+/HER2- breast cancer: chemo-naïve front-line setting and chemo-resistant late-line setting.

About DualityBio

Duality Biotherapeutics (HKEX:09606) is a clinical-stage biotech company dedicated to the discovery and development of next-generation ADCs to treat cancer and autoimmune diseases. DualityBio has successfully built several cutting-edge ADC technology platforms with global intellectual property rights. Leveraging a robust pipeline, DualityBio is conducting multiple global clinical trials across 20 countries and has enrolled over 3,100 patients for multiple clinical-stage ADC candidates.

Additionally, DualityBio has established strategic collaborations with global MNCs and leading biotech innovators. As a global ADC powerhouse, DualityBio is developing novel ADCs, including bispecific ADC candidates, novel-payload ADC candidates, and autoimmune ADC candidates. For more information, please visit www.dualitybiologics.com.

Media Contact: PR@dualitybiologics.com