“AstraZeneca’s Faslodex has been cleared on both sides of the Atlantic for use in combination with a CDK4/6 inhibitor.
“In the EU, the drug’s use has been approved for use alongside the CDK4/6 inhibitor palbociclib to treat a certain form of breast cancer, in the US it can be prescribed in combination with the CDK4/6 inhibitor abemaciclib.
“Both the European Commission and US Food and Drug Administration have approved the combination for the treatment of hormone receptor-positive (HR+), human epidermal growth factor receptor 2 negative (HER2-) locally advanced or metastatic breast cancer in women who have received prior endocrine therapy.”
Non-metastatic breast cancers are most often treated with surgery, but if the tumors are fairly large, or involve nearby lymph nodes, neoadjuvant (pre-operative) treatments with chemotherapy (NAC) are done first. NAC often reduces the tumor size and kills cancer cells in lymph nodes, if present, prior to surgery, improving the outcome. The best possible result of neoadjuvant treatment is pCR (pathologic compete response), when the tumor is no longer visible in imaging studies. Here, I review the new directions in which neoadjuvant treatments are evolving.
Today, treatments for metastatic breast cancers are tailored for specific subtypes. Starting with the introduction of the drug trastuzumab (Herceptin) for HER2-positive cancers, new, more specific treatment options were eventually developed and approved for other types as well. Estrogen deprivation endocrine therapies, lately prescribed in combination with CDK4/6 inhibitors, are used in estrogen receptor (ER)-positive cancers. Triple negative cancers (TNBC) are still treated mostly with chemotherapy, but immune checkpoint drugs and PARP inhibitors are explored in clinical trials, with some successes reported.
However, neoadjuvant treatments (except for HER2+ cancers) remain largely limited to chemotherapy regimens. This is starting to change now, with new approaches tailored to the cancer type being investigated in clinical trials.
In this regard, it is important to mention the I-SPY2 trial, NCT01042379, which started in 2010 and is for women with stage II-III breast cancer. It offers about a dozen drugs that are chosen based on particular features of the newly diagnosed cancers. This trial has a unique design and has produced some important results. Additional treatments and trials for various types of breast cancer are discussed below. Continue reading…
“Twelve weeks of neoadjuvant T-DM1 (ado-trastuzumab emtansine; Kadcyla) with or without endocrine therapy induced superior pathologic complete response (pCR) compared with trastuzumab (Herceptin) plus endocrine therapy in patients with HER2-positive/HR-positive early breast cancer, according to findings recently published online in theJournal of Clinical Oncology.
“In the prospective, neoadjuvant phase II ADAPT trial conducted by the West German Study Group, pCR was 41.0% for patients assigned to T-DM1 alone and 41.5% for those who received T-DM1 and endocrine therapy. In contrast, 15.1% of patients assigned to trastuzumab and endocrine therapy had a pCR (P<.001).”
“A duration of endocrine therapy beyond 5 years has gained traction in the treatment of endocrine receptor (ER)-positive early-stage breast cancer. Long-term use of aromatase inhibitors (AIs), however, may increase the risk of bone loss and bone fracture. Data suggest that the use of bone-targeted agents can substantially reduce the risk of osteoporotic complications associated with AI use, and even reduce the risk of bone recurrence in postmenopausal women with early-stage breast cancer.”
“Endocrine therapy remains an integral part of the treatment paradigm for patients with estrogen receptor (ER)–positive breast cancer; however, questions remain on which patients should continue their therapy beyond 5 years.
” ‘The idea [is] that most patients with hormone receptor (HR)-positive breast cancer who are still on endocrine therapy at 5 years are going to merit some sort of discussion about whether they should continue or not, and it is okay to individualize that decision on the basis of the patient preferences, side effects, and symptom burden,’ said Amye J. Tevaarwerk, MD.”
Doctors prescribe drugs known as CDK inhibitors to treat some women with estrogen-receptor-positive (ER+) metastatic breast cancer. Research into these drugs is ongoing, and new, promising CDK inhibitor options are on the horizon. Here, I address the current outlook for CDK inhibitors in ER+ breast cancer.
First, some background: ER+ breast cancers comprise about 70% of all breast cancers. The name reflects the fact that cells of these cancers express estrogen receptors (ERs), which are protein features targeted by many treatment strategies for this cancer type. The estrogen receptor (ER) protein is a treatment target not only because “it is there,” but mainly because it drives tumor cell proliferation in ER+ breast cancer. The activity of the ER depends on its binding to the hormone estrogen, and treatments known as endocrine drugs aim to prevent this interaction. Some endocrine drugs inhibit the synthesis of estrogen in the body (e.g., aromatase inhibitors, such as letrozole and anastrozole), and others prevent the interaction of estrogen with ERs (e.g., ER modulators such as tamoxifen, or the pure anti-estrogen drug fulvestrant). The problem of course is that, in metastatic breast cancer, resistance develops to each and every endocrine drug used. Continue reading…
“Progression-free survival was more than doubled for patients with metastatic hormone receptor (HR)-positive, HER2-negative breast cancer resistant to aromatase inhibitor therapy by adding everolimus (Afinitor) to treatment with the endocrine therapeutic fulvestrant (Faslodex), according to data from the PrECOG 0102 phase II clinical trial presented at the 2016 San Antonio Breast Cancer Symposium, held Dec. 6–10.
” ‘Endocrine therapy, often with an aromatase inhibitor, is the standard of care for most patients with HR-positive advanced breast cancer,’ said Noah S. Kornblum, MD, assistant professor of medicine at Albert Einstein College of Medicine and attending physician, medicine at Montefiore Einstein Center for Cancer Care. ‘However, over time, resistance to aromatase inhibitors develops and treating patients with aromatase inhibitor–resistant disease remains a challenge.’ ”
“Neoadjuvant endocrine therapy – designed to reduce the size of breast tumors before surgical removal – appears to be as effective as neoadjuvant chemotherapy for patients with localized, estrogen-receptor (ER)-positive breast cancer with considerably fewer side effects. The study conducted by a Massachusetts General Hospital (MGH) Cancer Center research team appears in the current print issue of JAMA Oncology and was published online earlier this year.”
“A dual approach to overcoming resistance to endocrine therapy in patients with advanced hormone receptor (HR)–positive breast cancer is under investigation in a phase III trial that adds the novel drug entinostat to standard exemestane therapy after disease progression.
“The combination has generated excitement in the oncology drug development field after demonstrating an 8-month overall survival (OS) benefit over exemestane alone in the phase II ENCORE 301 study. Those positive results prompted the FDA to grant a breakthrough therapy designation to entinostat in this setting.”