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Targeted Cancer Therapy
Targeted cancer therapies interfere with cancer cell growth and division in different
ways and at various points during the development, growth, and spread of cancer. Many of
these therapies focus on proteins that are involved in the signaling process. By blocking
the signals that tell cancer cells to grow and divide uncontrollably, targeted cancer
therapies can help to stop the growth and division of cancer cells.
Targeted Cancer Therapy - Small-molecule drugs
“Small-molecule” drugs block specific enzymes and GFRs involved in cancer
cell growth. These drugs are also called signal-transduction inhibitors. Gleevec®
(STI–571 or imatinib mesylate) is a small-molecule drug approved by the FDA to treat
gastrointestinal stromal tumor (a rare cancer of the gastrointestinal tract) and certain
kinds of chronic myeloid leukemia (1, 2). Gleevec targets abnormal proteins, or enzymes,
that form inside cancer cells and stimulate uncontrolled growth. Iressa® (ZD1839 or
gefitinib) is approved by the FDA to treat advanced non-small cell lung cancer. This drug
targets the epidermal growth factor receptor (EGFR), which is overproduced by many types
of cancer cells. Other small-molecule drugs are being studied in clinical trials in the
United States.
Targeted Cancer Therapy - Apoptosis-inducing drugs
“Apoptosis-inducing” drugs cause cancer
cells to undergo apoptosis (cell death) by interfering with proteins involved in the
process. Velcade® (bortezomib) is approved by the FDA to treat multiple myeloma that has
not responded to other treatments (3). Velcade causes cancer cells to die by blocking
enzymes called proteasomes, which help to regulate cell function and growth. Another
apoptosis-inducing drug called Genasense™ (oblimersen), which is only available in
clinical trials, is being studied to treat leukemia, non-Hodgkin’s lymphoma, and
solid tumors. Genasense blocks the production of a protein known as BCL–2, which
promotes the survival of tumor cells. By blocking BCL–2, Genasense leaves the cancer
cells more vulnerable to anticancer drugs.
Targeted Cancer Therapy - Monoclonal antibodies
Monoclonal antibodies, cancer vaccines, angiogenesis inhibitors, and gene therapy are
considered by some to be targeted therapies because they interfere with the growth of
cancer cells.
Infromation from National Cancer Institute
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