2026 Breast Cancer | New Mechanistic Discoveries + Multiple New Drugs Accelerating toward Market Launch
Breast cancer remains the most commonly diagnosed malignant tumor among women worldwide, with more than 2.3 million new cases annually. The 5‑year survival rate for patients with advanced metastatic disease is less than 30%. Clinical treatment faces three major challenges: endocrine therapy resistance, limited options for HER2 low‑expression/negative disease, and modest benefits from immunotherapy. In addition, the high incidence of breast cancer‑related cardiovascular complications further increases survival risks, highlighting the urgent need to address multiple dilemmas. In recent years, paradigm shifts have occurred in breast cancer diagnosis and treatment, enabling more patients to achieve long‑term survival with the disease.
I. Breakthroughs in Basic Research: Targeting Core Pain Points of Breast Cancer Treatment and Long-Term Complications
1.Landmark Discovery: Unraveling the Pathogenic Mechanism of Breast Cancer-Related Atrial Fibrillation
On March 5, 2026, Professor Xia Yunlong from Dalian Medical University, together with the team led by Professor Zhenwei Pan from Harbin Medical University, published a landmark study in the top cardiovascular journal European Heart Journal. It was confirmed for the first time that soluble ADAM10 secreted by breast cancer can independently induce atrial fibrosis and atrial fibrillation through remote tumor-heart crosstalk, and this mechanism is independent of traditional risk factors and cardiotoxicity secondary to antitumor therapy.
Source: Reference 1
Breast cancer increases susceptibility to atrial fibrillation in syngeneic tumor-bearing mouse models.
2.Chinese team cracks endocrine resistance in HR-positive breast cancer
Prof. Shao Zhimin and Jiang Yizhou from Fudan University Shanghai Cancer Center published a landmark study in Cancer Research, challenging the one-size-fits-all endocrine therapy for HR+/HER2− breast cancer. Using multi-omics sequencing and integrated clinical data, the team established the "Fudan Four-Subtype Classification" system and proposed a subtype-guided precision strategy, which has been verified to show superior efficacy over conventional treatment in real-world cohorts.
Source: Reference 2
3.Novel target discovered for anti-PD-1 resistant triple-negative breast cancer
Shao Zhimin and Jiang Yizhou’s team published phase II results in Nature Medicine. Using AI‑enabled integration of multimodal data from 528 patients, the team identified for the first time that antigen‑presenting mast cells (apMC) are critical for anti‑PD‑1 efficacy: apMC activate tumor‑reactive T cells and boost antitumor immune responses, providing a novel intervention target for immunotherapy‑resistant triple‑negative breast cancer.
Source: Reference 3
apMC is associated with enhanced anti-PD-1 efficacy.
4. PD-1/CTLA-4 bispecific antibody overcomes immunotherapy resistance in triple-negative breast cancer
Cadonilimab (PD-1/CTLA-4 bispecific antibody), developed by Akeso Biopharma, was evaluated in the COMPASSION-03 study published in Lancet Oncology. In first-line treatment of advanced triple-negative breast cancer (TNBC), cadonilimab combined with chemotherapy achieved an objective response rate (ORR) of 56.3% and significantly prolonged median progression-free survival (PFS).Clear clinical benefit was observed even in PD-L1-negative patients, challenging the traditional view that TNBC is unresponsive to immunotherapy, and establishing a new first-line option for this subtype.
Source: Reference 4
II. Company Pipeline Strategy: Marketed Drugs Solidify Foundation, Clinical-Stage Drugs Accelerate Launch
1.Marketed Drugs: Reshaping Treatment Standards for All Subtypes
Drug/Regimen | Indication | Core Value |
Trastuzumab deruxtecan (T-DXd) | HER2-positive / HER2-low advanced breast cancer | A new-generation ADC agent covering all HER2 expression populations and overcoming resistance |
Sacituzumab govitecan (SG) | HR+/HER2- and triple-negative advanced breast cancer | A Trop-2 ADC and standard regimen for refractory metastatic breast cancer |
Cadonilimab + chemotherapy | First-line treatment of advanced triple-negative breast cancer | A domestic bispecific antibody breakthrough that expands the population benefiting from immunotherapy |
Abemaciclib | HR+/HER2- advanced / early breast cancer | A benchmark CDK4/6 inhibitor that improves disease-free survival |
2. 2026 FDA Key Approval Updates + Summary of Novel Immunotherapy Bispecific Antibodies
Drug/Regimen Name | Developer | Target / Mechanism of Action | Indication |
Dato-DXd (Datroway) | Daiichi Sankyo + AstraZeneca | TROP2 ADC | Unresectable / metastatic triple-negative breast cancer (not eligible for PD-1/PD-L1 immunotherapy) |
Giredestrant + Everolimus | Roche | Oral SERD + mTOR inhibitor | ESR1-mutated, HR+/HER2- locally advanced / metastatic breast cancer (after progression on endocrine therapy) |
Zovegalisib (RLY-2608) + Fulvestrant | Relay Therapeutics | PI3Kα inhibitor + endocrine therapy | PIK3CA-mutated, HR+/HER2- advanced breast cancer (after progression on CDK4/6 inhibitor) |
ART6043 + Olaparib | Artios Pharma | Polθ inhibitor + PARP inhibitor | gBRCA-mutated, HER2-negative advanced breast cancer (no prior PARP inhibitor treatment) |
PD-L1/TGF-β Bispecific Antibody (SHR-1701) + Chemotherapy | Hengrui Medicine | PD-L1/TGF-β bispecific antibody | Advanced triple-negative breast cancer |
CD47/PD-L1 Bispecific Antibody (AK127) | Akeso Biopharma | CD47/PD-L1 bispecific antibody | Refractory metastatic breast cancer |
Reference
1.Xia Y, Pan Z, et al. Breast tumour-secreted ADAM10 mediates atrial fibrogenesis and fibrillation. Eur Heart J. 2026;ehad123.
2.Zhu XZ, Zhang HY, Zhou YF, et al. Subtyping-Directed Precision Treatment Refines Traditional One-Size-Fits-All Therapy for HR+/HER2- Breast Cancer. Cancer Res. 2025;85(20):3983-3998. doi:10.1158/0008-5472.CAN-24-5002.
3.Wu SY, Jin X, Liu Y, et al. Mobilizing antigen-presenting mast cells in anti-PD-1-refractory triple-negative breast cancer: a phase 2 trial. Nat Med. 2025;31(7):2405-2415. doi:10.1038/s41591-025-03776-7
4.Gao X, Xu N, Li Z, et al. Safety and antitumour activity of cadonilimab, an anti-PD-1/CTLA-4 bispecific antibody, for patients with advanced solid tumours (COMPASSION-03): a multicentre, open-label, phase 1b/2 trial. Lancet Oncol. 2023;24(10):1134-1146. doi:10.1016/S1470-2045(23)00411-4