Posted online April 22, 2013 on www.jco.org.
New findings from a retrospective study suggest that targeted anti-HER2 therapy may slow disease progression in patients with advanced lung cancer who carry a specific alteration in HER2—a protein that controls cancer growth and spread, found on some cancer cells, such as breast, ovarian, and lung cancer cells.
That specific HER2 alteration makes the protein permanently “switched on,” fueling tumor growth continuously. The alteration is very rare, occurring in only 1 or 2 percent of patients with lung cancer. While certain anti-HER2 drugs such as trastuzumab (Herceptin) have been very effective for some patients with breast cancer, there has not been much success with this approach for patients with lung cancer, until this study.
In the study, researchers detected HER2 alterations in the tumors of 65 out of 3,800 patients with non-small cell cancer (adenocarcinoma subtype) in three European countries. Most of the patients with the alterations were women and many were never smokers.
Sixteen patients, all diagnosed with stage IV lung cancer, received anti-HER2 treatment following standard chemotherapy. On average, anti-HER2 therapy delayed disease worsening by 5.1 months. Overall, nine out of 16 patients experienced some tumor shrinkage after one round of treatment with trastuzumab and an additional two patients experienced shrinkage after a second round of treatment (one with trastuzumab, one with afatinib). Lapatinib (Tykerb) and masatinib were completely ineffective.
What This Means for Patients
HER2 is a promising treatment target for lung cancer because several anti-HER2 drugs are readily available. Targeting HER2 is an example of personalized medicine, where efforts are made to match each patient to the most effective treatment based on the genetic makeup of their tumor. This study shows that researchers are finding more and more important mutations that drive lung cancer and matching them to targeted drugs.
Although the occurrence of HER2 alterations among patients with lung cancer is rare, it still amounts to several thousand cases in the United States alone for whom anti-HER2 therapy could be beneficial.
More research is needed to confirm these findings, but it appears that anti-HER2 drugs, such as trastuzumab, may be a reasonable treatment strategy for patients with rare HER2 mutations with advanced disease that worsened despite standard therapy.
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Last Updated: April 22, 2013