Targeted Therapies for Cancer Treatment
Targeted Therapy: A Focus on Specific Molecular Pathways in the Body
Cells take their instructions from proteins regarding cellular growth, division, and apoptosis (programmed cell death). Often in targeted therapy, specific proteins are targeted with a goal of interfering with or preventing instructions from reaching their recipients. Targeted therapy is designed to alter or inhibit the typical function of a specific protein.
According to a 2022 journal article by Shuel, S., most targeted therapies fall into one of two categories:
- monoclonal antibodies (target proteins on the outside of cells or in the extracellular space and interfere with signaling, often as it relates to cell growth, replication, or angiogenesis; drug names often end in -mab; includes EGFR inhibitors, VEGF inhibitors, antibody-drug conjugates; usually administered intravenously, by IV)
- small-molecule drugs (small enough to gain access inside cells so they aim for intracellular targets that lead to cell death or slowed cellular growth; drug names often end in -mib; includes protease inhibitors PARP inhibitors, BRAF inhibitors, kinase inhibitors; usually administered orally in tablets or capsules)
However, targeted therapies can also be classified as:
- hormone therapies
- signal transduction inhibitors
- gene expression modulators
- apoptosis inducers
- angiogenesis inhibitors
- immunotherapies
- toxin delivery molecules
Side Effects:
The side effects that accompany targeted therapies are based on the mechanism of action of the therapy.
Cutaneous toxicities (skin toxicities: rash and paronychia, inflammation of skin around nails) are common with EGFR inhibitors (epidermal growth factor receptor). This is because these receptors, EGFRs, are also on the surface of cells that make up the epidermis, or skin. Reducing and limiting sun exposure, prophylactic antibiotics, and topical treatments have all been recommended for the prevention and/or reduction of these skin toxicities.
Some additional targeted therapy side effects include high blood pressure (hypertension), congestive heart failure, impaired wound healing, deep vein thrombosis or pulmonary embolism, and increased risk of bleeding.
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Shuel, Sian L. “Targeted cancer therapies: Clinical pearls for primary care.” Canadian family physician Medecin de famille canadien vol. 68,7 (2022): 515-518. doi:10.46747/cfp.6807515
