SHANGHAI, China, July 28, 2026 —— Duality Biotherapeutics, Inc. (DualityBio, HKEX: 9606.HK, or "the Company") announced today that elfetabart drozuntecan (also known as elfe-d or DB-1311/BNT324), an investigational B7-H3-targeted antibody-drug conjugate (ADC) being developed in collaboration with BioNTech, has been granted Breakthrough Therapy Designation (BTD) by the Center for Drug Evaluation (CDE) of China's National Medical Products Administration (NMPA). This designation is for the treatment of patients with advanced/unresectable, or metastatic castration-resistant prostate cancer (mCRPC) whose disease has progressed following prior treatment with androgen receptor pathway inhibitors (ARPI) and taxane-based chemotherapy.

Dr. Hua Mu, Global Chief Medical Officer of DualityBio, stated: “We are delighted to see elfetabart drozuntecan receive its first BTD from China's NMPA. Following the U.S. FDA’s Fast Track designation this marks another important recognition by regulatory authorities of the drug’s clinical potential. For patients with mCRPC who have progressed after ARPI and taxane-based chemotherapy, there are currently limited clinical options representing a significant unmet medical need. Leveraging our leading DITAC platform, we will continue to work closely with our partner BioNTech to advance the global clinical development of elfetabart drozuntecan, with the aim to further evaluate its therapeutic potential across multiple solid tumor types.”

About elfetabart drozuntecan

Elfetabart drozuntecan (also known as elfe-D or DB-1311/BNT324）is a next-generation topoisomerase-I-inhibitor-based ADC candidate targeting the immune checkpoint protein B7-H3. The transmembrane glycoprotein B7-H3 plays a critical role in the anti-tumor immune response and the shaping of the tumor microenvironment. B7-H3 is overexpressed in a range 

of solid tumors, with limited expression in healthy tissues, and has been associated with disease progression and very poor prognosis.¹ Preclinical studies have shown that elfetabart drozuntecan exhibits antitumor activity in various solid tumor models.² Clinical data from the ongoing Phase 1/2 trial (DB-1311-O-1001 NCT05914116, DB-1311-201 NCT06953089, BNT324-01 NCT06892548)  has demonstrated antitumor activity and a manageable safety profile for elfetabart drozuntecan in patients with advanced solid tumors.³

Previously, Elfe-D received Fast Track Designation from the U.S. Food and Drug Administration (FDA) for the treatment of patients with advanced/unresectable or mCRPC. It was also granted Orphan Drug Designation for the treatment of esophageal squamous cell carcinoma (ESCC) and small cell lung cancer (SCLC).

Elfetabart drozuntecan is currently being evaluated in a pivotal Phase 3 clinical trial (NCT07365995) in patients with first-line mCRPC and in a Phase 1/2 clinical trial (NCT05914116) in patients with advanced or metastatic solid tumors.In addition, two ongoing clinical trials are evaluating the potential of elfetabart drozuntecan in combination with pumitamig, an investigational PD-L1xVEGF-A bispecific immunomodulator being developed by BioNTech and Bristol Myers Squibb. A Phase 2 clinical trial (NCT06953089) is evaluating the treatment combination in multiple solid tumors, and a Phase 1/2 clinical trial (NCT06892548), sponsored by BioNTech, is evaluating the treatment combination in patients with advanced/metastatic or relapsed/progressive SCLC and non-small cell lung cancer (NSCLC).

About DualityBio

DualityBio is a clinical-stage innovative biopharmaceutical company dedicated to developing next-generation ADCs for patients with cancer and autoimmune diseases. The Company has successfully built multiple next-generation ADC technology platforms with global intellectual property rights. Grounded in a deep understanding of disease biology, DualityBio has established a robust clinical-stage ADC pipeline and is conducting multiple global, multicenter clinical trials across nearly 20 countries, with over 3,500 patients enrolled to date. Furthermore, 

DualityBio has entered into several out-licensing collaborations with global pharmaceutical companies and leading innovative biotech firms. Serving as a global engine for ADC innovation, DualityBio continues to develop next-generation novel ADCs, including bispecific ADCs, ADCs with novel payloads, and autoimmune ADCs.

For more information, please visit www.dualitybiologics.com.

Media Contact: PR@dualitybiologics.com

Investor Contact: IR@dualitybiologics.com

Reference

1. Ranjana K. Kanchan, et al. Biochim Biophys Acta Rev Cancer. 2022 Sep;1877(5):188783.

2.Li C, Yao J, et al. Cancer Res (2023) 83 (7_Supplement):2967.

3. Data on file.