Overview Targeted Therapy Drugs/Antibodies Mechanism of Action Toxicity Hydroxyurea Inhibits ribonucleotide reductase GI upset and myelosupression Trastuzumab Anti-HER-2 (erb-B2) monoclonal antibody Cardiotoxicity Tamoxifen and raloxifene Selective estrogen receptor modulator ↑ risk of endometrial carcinoma and hot flashes Imatinib bcr-abl tyrosine kinase inhibitor Fluid retention Rituximab anti-CD20 monoclonal antibody - Vemurafenib Inhibitor of BRAF - Hydroxyurea Mechanism inhibits ribonucleotide reductase leads to decreased DNA synthesis S-phase specific Clinical use melanoma CML sickle cell disease via increased HbF Toxicity myelosuppression GI upset Trastuzumab (Herceptin) Mechanism anti-HER-2 (erb-B2) monoclonal antibody Clinical use HER-2 positive breast cancer Toxicity cardiotoxicity Tamoxifen, raloxifene Mechanism selective estrogen receptor modulator (SERM) estrogen antagonist in estrogen receptor-positive breast cancer cells estrogen agonist in other tissues bone Clinical use breast cancer prevent osteoporosis Toxicity ↑ risk of endometrial carcinoma tamoxifen only via partial agonist effects raloxifene is endometrial antagonist hot flashes Imatinib (Gleevec) Mechanism Philadelphia chromosome bcr-abl tyrosine kinase inhibitor t(9;22) translocation Clinical use CML GI stromal tumors Toxicity fluid retention Rituximab Mechanism anti-CD20 monoclonal antibody most B cell neoplasms are CD20 positive Clinical use non-Hodgkin's lymphoma chronic lymphocytic leukemia rheumatoid arthritis with methotrexate