Tykerb® Shows Benefit in Inflammatory Breast Cancer
by Dr. C.H. Weaver M. D. updated 4/2018
In a Phase II clinical trial, treatment with the targeted therapy Tykerb® (lapatinib) reduced the extent of cancer in 39% of women with HER2-positive, relapsed or refractory inflammatory breast cancer. These results were published in Lancet Oncology.
About Inflammatory Breast Cancer
Inflammatory breast cancer (IBC) is an aggressive type of breast cancer with symptoms that differ from other types of breast cancer. The redness, warmth, and swelling that often accompany IBC are caused by the blockage of lymph vessels by cancer cells. At the time of diagnosis, most women with IBC will have lymph node metastases and roughly one-third will have distant metastases.
Many of these cancers express the tyrosine kinase receptors HER2 and/or EGFR. Tyrosine kinases are proteins involved in the proliferation and survival of cells. Because tyrosine kinases often function abnormally in cancer cells, drugs that interfere with these proteins play an important role in the treatment of several types of cancer. Tykerb is one such drug. It is an oral medication that targets both HER2 and EGFR.
The HER2 pathway is a biological pathway involved in cellular replication and growth. Breast cancers that overexpress (make too much of) HER2 are referred to as HER2-positive. Treatment of HER2-positive breast cancer often includes the targeted therapy Herceptin® (trastuzumab).
Tykerb is oral medication that targets both HER2 and a related protein that can also function abnormally in breast cancer cells: EGFR. Tykerb may be used to treat advanced HER2-positive breast cancer after other treatments—including Herceptin—have failed.
To evaluate the safety and effectiveness of Tykerb among women with HER2-positive, relapsed or refractory inflammatory breast cancer, an international group of researchers conducted a Phase II clinical trial among 126 women. All of the women had experienced cancer progression or relapse after treatment that included chemotherapy and (in most cases) Herceptin.
Study participants were treated with Tykerb once per day until the cancer progressed or the patient experienced unacceptable side effects.
- 39% of women experienced a partial reduction in detectable cancer.
- Median survival without cancer progression was 14.6 weeks.
- Diarrhea, the most common side effect, was reported by 59% of women.
The researchers conclude that Tykerb is potentially effective for women with HER2-positive, relapsed or refractory inflammatory breast cancer.
Tykerb plus Taxol Is Active in Inflammatory Breast Cancer
Tykerb® plus Taxol® (paclitaxel) appears to provide benefit in the initial treatment of inflammatory breast cancer, according to results published in the Journal of Clinical Oncology.
To evaluate the efficacy, safety, and tolerability of first-line treatment of IBC with daily Tykerb followed by daily Tykerb plus weekly Taxol, researchers studied 49 women. Participants were divided into two groups: those with HER2-positive disease and those with HER2-negative, EGFR-positive disease. (However, due to low patient numbers and results from a parallel study indicating a lack of benefit of Tykerb in HER2-negative, EGFR-positive IBC, this group did not continue on the study.) Patients received 14 days of Tykerb followed by 12 weeks of daily Tykerb and weekly Taxol; they then underwent surgery or additional chemotherapy.
The overall response rate for the HER2-positive group was 78%. Common side effects, including diarrhea, rash, nausea, and alopecia, were consistent with expectations and observed in less than half of these patients.
The researchers concluded that daily Tykerb followed by daily Tykerb plus weekly Taxol is active in the treatment of patients with HER2-positive IBC. The combination was generally well tolerated and without unexpected side effects.
Kaufman B, Trudeau M, Awada A et al. Lapatinib monotherapy in patients with HER2-overexpressing relapsed or refractory inflammatory breast cancer: final results and survival of the expanded HER2+ cohort in EGF103009, a phase II study. Lancet Oncology [early online publication]. April 27, 2009.
Boussen H, Cristofanilli M, Zaks T, et al. Phase II study to evaluate the efficacy and safety of neoadjuvant lapatinib plus paclitaxel in patients with inflammatory breast cancer. Journal of Clinical Oncology [early online publication]. June 7, 2010.
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