Is there a way to make cancers that stop responding to hormones increase their sensitivity to these drugs? Preclinical evidence suggests Herceptin (trustusumab) can restore and amplify responsiveness to hormonal therapy. The combination of Tykerb, which like Herceptin works on the HER receptor, and Femara is FDA approved and is thought to work through this mechanism. A randomized phase III TAnDEM study investigated Trastuzumab plus Arimidex(anastrozole) versus anastrozole alone for the treatment of postmenopausal women with receptors was for epidermal growth factor (EGFR), that suggests responsiveness to Herceptin, and hormones in metastatic breast cancer. Patients who received trastuzumab and anastrozole had longer period to progression (PFS, progression free survival) than patients who received anastrozole only. There was, however, no difference in overall survival between the two treatments. The numbers of adverse events and severe adverse events from treatment were higher with the to drug arm of the study compared to anastrozole only arm. This was a crossover design, in which patients who failed on anastrozole arm could crossover to the combination arm, which may have interfered with finding a difference in survival between the two arms.
Much more research needs to be done and guidelines have not yet incorporated Herceptin and Arimidex as standard recommendation. The editorial that accompanied the publication of the study suggested that such evidence, “should be viewed as pioneering and hypothesis driven; they are likely to become obligatory references in the field of HER2 breast cancer.”
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