Targeted Therapy

Targeted therapy refers to the development of treatments that selectively target specific molecules or pathways that are involved in disease pathogenesis. Designed to interact with specific markers necessary for disease progression, the goal of targeted therapies is to fight specific diseases with more precision and potentially fewer side effects. Targeted therapy involves various means of specifically targeting molecular pathways or cells involved in disease processes. Some common methods of targeted therapy include:

• Monoclonal Antibodies (mAb): mAbs are engineered to recognize and bind to specific target molecules, such as cell surface receptors or growth factors, to block their activity or promote immune-mediated destruction. Examples in cancer treatment include trastuzumab (Herceptin), which targets HER2 in breast cancer, and pembrolizumab (Keytruda), which blocks the PD-1 checkpoint inhibitor in certain types of cancer.

• Small Molecule Inhibitors: Small molecules can target intracellular signaling pathways, such as tyrosine kinase inhibitors (TKIs) that inhibit specific receptor tyrosine kinases involved in cancer cell growth. They have the ability to cross cell membranes and engage with specific cell targets and are usually designed to interfere with the enzymatic activity of the target protein. Some examples are bortezomib, a small molecule proteasome inhibitor; imatinib, a small molecule tyrosine kinase inhibitor, and seliciclib, a small molecule cyclin-dependent kinase inhibitor.

Examples include imatinib (Gleevec) and dasatinib (Sprycel), both TKIs for chronic myeloid leukemia.

• Gene Therapy: Gene therapy aims to deliver functional genes to replace missing or mutated ones or modulate gene expression. For example, in inherited retinal diseases, gene therapy can introduce functional copies of genes to replace mutated ones responsible for vision loss.

Targeted therapies are being researched for several applications, including but not limited to:

• Cancer Treatment: Targeted therapy is well-established in oncology, with numerous mAbs, small molecules, and gene therapies being used. Targeted therapy can reduce toxicity compared to chemotherapy and improve response rates for certain types of cancer, such as melanoma and lung cancer.

• Inflammatory Diseases: Targeted therapies for inflammatory diseases aim to block specific proinflammatory cytokines or immune cells. Examples include infliximab (Remicade) for rheumatoid arthritis and ustekinumab (Stelara) for psoriasis.

• Immunotherapy: Targeted therapy in immunotherapy aims to activate or inhibit specific immune cells for cancer treatment. For example, chimeric antigen receptor (CAR)-T cell therapy uses genetically engineered T cells to selectively target cancer cells.

Some specific markers for targeted therapy include the:

• EGFR Pathway: MAbs such as cetuximab (Erbitux) and panitumumab (Vectibix) target epidermal growth factor receptor (EGFR) in certain cancers, improving response to chemotherapy or radiation therapy.

• BRAF Mutation: Vemurafenib (Zelboraf) is a small-molecule inhibitor targeting BRAF V600E mutation, resulting in improved survival in patients with metastatic melanoma.

• HER2 Biomarker: Trastuzumab (Herceptin) is a mAb targeting HER2, a biomarker over-expressed in certain breast cancers. HER2-positive breast cancer patients have shown improved survival and response rates with trastuzumab therapy.

Working on the above research areas? Learn more about specific ELISA available for each: