- Question from KF: What is the latest news about Tykerb for metastatic breast cancer treatment, especially for brain metastasis? Will it likely be given in addition to Herceptin (especially if Herceptin is still working in the rest of the patient's body) or instead of Herceptin (if/when brain metastasis occurs)? Is there other info or online references about this new drug now?
- Answers —Nicholas Robert, M.D.: One of the big news items that came out of the American Society of Clinical Oncology meeting was Tykerb (chemical name: lapatinib). This is a new oral drug, still not commercially available, which is different from Herceptin (chemical name: trastuzumab) and works a bit differently. Trastuzumab attaches to part of the HER2 molecule, whereas lapatinib inhibits an enzyme called tyrosine kinase and inhibits both the HER2 molecule and other molecules called HER1.
At the ASCO meeting it was reported that patients who had metastatic HER2-positive cancer and who had the tumor progress after being treated with trastuzumab in chemotherapy were randomized to be either treated with chemotherapy or chemotherapy plus lapatinib. The patients who got the combination did better with a higher response rate and longer time before their cancer progressed. These results were so impressive that the trials were closed early and what's exciting is that we now have another drug that has targeted tumors that are HER2-positive. The fact that it's oral is also attractive. That's the good news.
In another trial, the patients with brain metastasis were treated and the hope was this would get into the brain. The small number of patients that were treated, less than 40, showed some responses but only in a few patients, raising the issue as to whether this drug will really be useful for brain metastasis. Lastly, the idea of using the combination of Herceptin and Tykerb is interesting, but we'll need more information before we know whether it's a good idea. There is a compassionate expanded access program through the drug sponsor, which is GlaxoSmithKline, but I think the bigger question is, "Where is it going to fit?" I think that question will not be really answered adequately until we do another randomized trial comparing that population at the trial, treating them with either chemotherapy and Tykerb versus chemotherapy and Herceptin, and learn which is the better treatment. In the meantime, some of us will have the opportunity to do another trial, now in the adjuvant setting where patients who've had a history of HER2-positive breast cancer and completed their chemotherapy will be randomized to receive Tykerb or a placebo. These will be patients who were diagnosed before we learned about the positive role of Herceptin. There's certainly a discussion of Tykerb versus Herceptin in the adjuvant setting.
- Jennifer Griggs, M.D., M.P.H.: Like all good studies, we have more questions than answers. We see this over and over again when we have a new drug: we ask ourselves how we use the drug, for whom and how long, and where in the treatment course.
On Wednesday, June 21, 2006, our Ask-the-Expert Online Conference was called Updates from the 2006 ASCO Annual Meeting. Nicholas Robert, M.D. and moderator Jennifer Griggs, M.D., M.P.H. answered your questions about recent advances in breast cancer treatment, updates on breast cancer genetics, information on diet and risk of recurrence, and more.
The materials presented in these conferences do not necessarily reflect the views of breastcancer.org. A qualified healthcare professional should be consulted before using any therapeutic product or regimen discussed. All readers should verify all information and data before employing any therapies described here.
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Nicholas Robert, M.D. is a co-chair of the Breast Committee of the U.S. Oncology Research Network and also chairs the Cancer Committee and Research Committee of the Inova Fairfax Hospital's Cancer Center.
Jennifer Griggs, M.D., M.P.H. is a medical oncologist specializing in the treatment of breast cancer, with a a special interest in cancer survivorship, patient-physician communication, and quality of care for women with breast cancer.
