Targeted Cancer Therapy

Targeted therapy refers to drugs that selectively block specific molecular targets — proteins, enzymes, receptors, or genetic alterations — that drive cancer cell growth, proliferation, and dissemination. While conventional chemotherapy affects all rapidly dividing cells, both cancerous and healthy, targeted therapies act more selectively on cancer cells and generally cause less systemic toxicity. The era of targeted therapy began with the use of imatinib in CML in 2001 and has reshaped the paradigm of oncology.

Targeted therapies are divided into two main groups: (1) Small-molecule inhibitors — drugs that enter the cell and bind intracellular targets such as tyrosine kinases, proteasomes, BRAF, and EGFR (imatinib, erlotinib, vemurafenib, ibrutinib); (2) Monoclonal antibodies — large-molecule drugs that bind cell-surface targets such as HER2, EGFR, VEGF, and CD20 (trastuzumab, rituximab, bevacizumab, cetuximab).

Targeted therapies require predictive biomarker testing — identifying genetic, molecular, or proteomic changes (mutation, fusion, amplification, overexpression) in the patient's tumor. A personalized medicine approach selects the most suitable targeted treatment for each patient. For example: HER2-positive breast cancer → trastuzumab; BRAF V600E-positive melanoma → vemurafenib + cobimetinib; EGFR-mutant non-small cell lung cancer → osimertinib; CD20-positive B-cell lymphoma → rituximab.