“The use of afatinib or afatinib plus vinorelbine during or after treatment with trastuzumab, lapatinib, or both failed to show a patient benefit in women with HER2-positive breast cancer with progressive brain metastases compared with investigator’s choice of treatment, according to the results of a phase II study published in Lancet Oncology.
“Afatinib, an oral inhibitor of the ErbB family of proteins, did benefit about one-third of patients assigned to the treatment, but had no better activity than investigator’s choice of therapy, which consisted mostly of trastuzumab or lapatinib plus chemotherapy.
“ ‘No objective responses were achieved in patients treated with afatinib alone, but around one-third of patients, including those treated with afatinib alone, did not have disease progression during the first 12 weeks,’ wrote researcher Javier Cortés, MD, of Vall d’Hebron Institute of Oncology in Barcelona, and colleagues. ‘No further development of afatinib for HER2-positive breast cancer is currently planned.’ “
“The combination of lapatinib (Tykerb) and trastuzumab (Herceptin) is active and well-tolerated when given to patients with human epidermal growth factor receptor 2-positive (HER2) metastatic breast cancer (MBC) who have received up to two lines of therapy for advanced disease, a nonrandomized phase II study now shows.
“What’s more, early metabolic imaging by 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG-PET/CT) appears to provide the key to selecting patients who can be treated with targeted regimens and spared the toxicity of chemotherapy, Nancy U. Lin, MD, Susan F. Smith Center for Women’s Cancers, Dana-Farber Cancer Institute, Boston, Ma., and colleagues report online in the Journal of Clinical Oncology.
” ‘Because the number of treatment options and their cost for patients with HER2-positive breast cancer continues to increase, a key question is how best to tailor therapies to individual patients,’ said Lin. ‘In the metastatic setting, predictive tests for clinical benefit could spare patients unnecessary toxicity and cost from ineffective therapies and maximize the likelihood of meaningful improvements from treatment. In the early-stage setting, predictive tests may reduce both under- and overtreatment.’ “
“In an analysis of the NeoALTTO trial reported in JAMA Oncology, Salgado et al found that a higher level of tumor-infiltrating lymphocytes was associated with improved pathologic compete response rate and event-free survival independent of neoadjuvant treatment received in patients with HER2-positive early breast cancer.
“In NeoALTTO, 455 patients were randomly assigned to receive neoadjuvant trastuzumab (Herceptin), lapatinib (Tykerb), or the combination for 6 weeks followed by the addition of weekly paclitaxel for 12 weeks and three cycles of fluorouracil, epirubicin, and cyclophosphamide after surgery. Percentage of tumor-infiltrating lymphocytes were measured by hematoxylin-eosin stained core biopsy sections taken at diagnosis.”
“High levels of tumor-infiltrating lymphocytes served as an independent positive predictive marker for EFS and pathological complete response in HER-2–positive early breast cancer treated with chemotherapy and anti-HER–2 agents, according a secondary analysis of the NeoALTTO trial.
“ ‘Increasingly, oncogenic addiction, in which tumors become dependent on a sole oncogenic pathway for growth, is thought to promote a tumor microenvironment conducive to immune escape,’ Sherene Loi, MD, PhD, of the Peter MacCallum Cancer Centre at the University of Melbourne, and colleagues wrote. ‘Although this had not been shown yet for HER-2 oncogenic signaling, one could speculate that anti-HER–2 therapy may not only work in a cell-intrinsic manner but may also reserve HER-2–induced immunosuppression as a mechanism for action.’
“The NeoALTTO trial included 455 women with HER-2–positive early-stage breast cancer between 2008 and 2010. The researchers randomly assigned patients to neoadjuvant treatment with trastuzumab (Herceptin, Genentech), lapatinib (Tykerb, GlaxoSmithKline) or both.
“Patients received the initial treatment for 6 weeks, followed by weekly paclitaxel for 12 weeks and three treatment cycles of fluorouracil, epirubicin and cyclophosphamide after surgery.”
“In HER2-positive breast cancer, lapatinib (Tykerb) combined with a taxane was linked to shorter progression-free survival (PFS) and more toxicity compared with trastuzumab (Herceptin) plus a taxane, according to results from an international trial.
“In addition, lapatinib plus a taxane was associated with more toxicity in patients with centrally confirmed HER2-positive tumors, and overall survival (OS) was worse in the confirmed HER2-positive group treated with lapatinib (ITT hazard ratio 1.28, 95% CI 0.95-1.72, P=0.11), they wrote in the Journal of Clinical Oncology.
” ‘Our results support the use of trastuzumab over lapatinib in the HER2 treatment-naive first-line metastatic setting,’ Gelmon’s group stated. ‘The NCIC CTG MA.31 trial was the first head-to-head comparison to our knowledge of trastuzumab and lapatinib in locally determined metastatic HER2-positive breast cancer, with separate analysis for centrally determined HER2 disease.’ “
The gist: Recent research suggests that women whose tumors have a mutation in the PIK3CA gene may be resistant to treatment with the drugs trastuzumab (Herceptin) and lapatinib. However, two new studies say that PIK3CA mutations can’t be used to predict how well Herceptin and lapatinib will work.
“While preclinical studies indicate that PIK3CA mutations result in resistance to the two HER2-targeted therapies trastuzumab and lapatinib, two recently published studies suggest that this mutation cannot be used as a predictive biomarker to guide therapy.
“The first study found that PIK3CA mutations are associated with a decreased benefit to neoadjuvant HER2-directed therapies. The second study showed that PIK3CA mutations did not affect outcomes for HER2-positive patients receiving adjuvant trastuzumab treatment.
“Preclinical studies using HER2-positive cell lines have previously shown that an additional mutation in PIK3CA, the alpha-catalytic subunit of PI3K, results in downstream constitutive signaling, making breast tumor cells that harbor both aberrations resistant to trastuzumab and lapatinib. PIK3CA is among the most commonly mutated oncogene in breast cancer and is present in about one-fourth of all HER2-positive breast cancers. Because of this prevalence and the effect of PI3K pathway activation on HER2 therapy, clinicians have posited that PIK3CA mutations may serve as predictive biomarkers, both preventing ineffectual therapy in some patients and guiding appropriate treatment choices.”
The gist: People whose HER2-positive breast cancer has spread to their central nervous system (CNS) might survive longer if they are treated with the drug Kadcyla than if they take capecitabine plus lapatinib. That was the conclusion of a recent clinical trial with volunteer patients. Our Chief Scientist speculates that the mild side effects of Kadcyla compared to those of the capecitabine/lapatinib combo might also make it a better choice.
“Patients with HER-2–positive advanced breast cancer treated with ado-trastuzumab emtansine experienced similar rates of central nervous system progression as those treated with capecitabine plus lapatinib, according to study results.
“However, among patients with treated, asymptomatic central nervous system (CNS) metastases at baseline, those assigned the antibody–drug conjugate ado-trastuzumab emtansine (Kadcyla, Genentech) experienced significantly longer OS than those assigned capecitabine plus lapatinib (Tykerb, GlaxoSmithKline).
“Ian E. Krop, MD, of the department of medical oncology at Dana-Farber Cancer Institute and Harvard University School of Medicine, and colleagues conducted a retrospective, exploratory analysis of data from the phase 3 EMILIA study.
“The EMILIA study included 991 patients with HER-2–positive advanced breast cancer who underwent previous treatment with trastuzumab (Herceptin, Genentech) and a taxane. Researchers randomly assigned 495 patients to ado-trastuzumab emtansine, and the other 496 received capecitabine plus lapatinib. Treatment continued until disease progression.”
The gist: Stage II and III breast cancer patients whose tumors are HER2-positive may benefit from longer treatment with the anti-HER2 drugs trastuzumab (aka Herceptin) and lapatinib (Tykerb). In a clinical trial, 28% of patients who received the drugs for 24 weeks had no more signs of an invasive tumor after their treatment. Only 12% of patients who received the drugs for 12 weeks had the same result. However, the difference in response was significant only in patients whose tumors were hormone receptor (HR)-positive and HER2-positive.
The gist: Before surgery to remove a tumor, breast cancer patients might take neoadjuvant therapy to shrink the tumor or otherwise help ensure a more successful surgery. A recent study concludes that combining two HER2-targeted drugs with chemotherapy might be the best neoadjuvant treatment choice for women with HER2-positive breast cancer. The researchers compared data from patients who received different combinations of chemotherapy, trastuzumab (Herceptin), and lapatinib (Tykerb). Patients who received all three had the highest chance of having no more signs of an invasive tumor after the treatment.
“For women with human epidermal growth factor receptor 2 (HER2)-positive breast cancer, combining two anti-HER2 agents with chemotherapy is the most effective treatment modality in the neoadjuvant setting, according to a meta-analysis published in the Journal of the National Cancer Institute.
“The study by Nagayama et al found that chemotherapy with trastuzumab (Herceptin) plus lapatinib (Tykerb), or with trastuzumab plus pertuzumab (Perjeta), resulted in a statistically significantly larger number of patients achieving pathologic complete response than did chemotherapy alone, chemotherapy with a single targeted therapy, or two anti-HER agents without chemotherapy. Ranking of treatment arms indicated that chemotherapy with trastuzumab plus pertuzumab “had the highest probability of being the best treatment arm in terms of [pathologic complete response],” the investigators stated.
“ ‘The growing number of HER2-targeted agents has created the need to define the optimal neoadjuvant therapy for HER2-positive breast cancer,’ the researchers wrote in explaining the rationale for the study. While other trials have been conducted to compare treatments, ‘it is difficult to integrate information on the relative efficacy of all tested regimens, since each trial has compared only a few treatments,’ the investigators noted.”