Recent Advancement in Targeted Therapy for Breast Cancer- A Comprehensive Overview

Breast cancer is the second leading cause of death for women worldwide and represents a major cause of cancer-related mortality .  The disease exhibits marked molecular heterogeneity, which has significant implications for prognosis and therapeutic decision-making. Traditional cytotoxic chemotherapy, while effective in many cases, is associated with substantial toxicity and limited specificity. Advances in molecular oncology have led to the development of targeted therapies that selectively inhibit key oncogenic pathways involved in tumor proliferation, survival, and immune evasion.

The primary objective of targeted therapy is to inhibit specific molecular targets that drive tumor growth and progression. Targeted therapeutic strategies—including monoclonal antibodies, small-molecule inhibitors, antibody–drug conjugates (ADCs), and immune checkpoint inhibitors—have significantly transformed the management and outcomes of breast cancer. HER2-directed therapies such as trastuzumab, pertuzumab, trastuzumab emtansine, and trastuzumab deruxtecan have dramatically improved outcomes in HER2-positive and HER2-low disease . Cyclin-dependent kinase 4/6 (CDK4/6) inhibitors have become a cornerstone of treatment for hormone receptor–positive breast cancer by overcoming endocrine resistance. Poly (ADP-ribose) polymerase (PARP) inhibitors exploit synthetic lethality in BRCA-mutated tumors, while PI3K inhibitors and immune checkpoint inhibitors have expanded therapeutic options for selected patient subgroups.

Despite significant advances, acquired resistance remains a major challenge in targeted breast cancer therapy. Novel agents targeting pathways such as AKT, CDKs, PARP, and growth factors—guided by molecular profiling and key mutations including BRCA1/2 and PIK3CA—have enabled more personalized treatment approaches.  This review summarizes current targeted therapeutic strategies in breast cancer, highlights pivotal clinical trial evidence, discusses practical clinical considerations, and outlines future directions toward precision oncology.