“As research of early-stage estrogen receptor (ER)-positive breast cancer continues, experts are relying more on extended adjuvant hormonal therapy with aromatase inhibitors, but are concerned about patient quality of life (QoL) with such treatment.
” ‘My passion is to really try to figure out how to make the side effects of these therapies more tolerable and how to help women be able to actually have reasonably good and normal QoL while they’re taking these therapies, so that we can increase compliance,’ said Michelle E. Melisko, MD.”
“Data from the phase II PERTAIN trial presented late last year at the 2016 San Antonio Breast Cancer Symposium (SABCS) showed that adding an aromatase inhibitor (AI) to pertuzumab (Perjeta) and trastuzumab (Herceptin) extended progression-free survival (PFS) by over 3 months versus trastuzumab plus an AI in patients with HER2-positive, HR-positive locally advanced or metastatic breast cancer.
“The median PFS was 18.89 months with the pertuzumab triplet compared with 15.80 months for trastuzumab and an AI alone (HR, 0.65; 95% CI, 0.48-0.89; P = .007). The objective response rates were 63.3% versus 55.7%, respectively.”
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…
“G1 Therapeutics, Inc., a clinical-stage oncology company, announced today the expansion of its pipeline of novel cancer therapies with the initiation of three development programs in breast cancer. G1 is enrolling a Phase 2 study of its intravenous CDK4/6 inhibitor trilaciclib for the treatment of triple-negative breast cancer (TNBC), and a Phase 1b/2a study of its oral CDK4/6 inhibitor G1T38 for the treatment of estrogen receptor-positive, HER2-negative (ER+, HER2-) breast cancer. In addition, G1 is advancing G1T48, its oral selective estrogen receptor degrader (SERD) with the goal of commencing a Phase 1 trial in the fourth quarter of 2017.”
“A tumor’s immune response to a single dose of the HER2 inhibitor trastuzumab predicted which patients with HER2-positive breast cancer would respond to the drug on a more long-term basis, according to the results of a study published recently in Clinical Cancer Research.
“In addition, Vinay Varadan, PhD, assistant professor at Case Western Reserve University School of Medicine and member of the Case Comprehensive Cancer Center, and his colleagues found that women with the HER2-enriched subtype of HER2-positive breast cancer—a subtype that is estrogen and progesterone receptor negative—had the highest rate of immune response to treatment with trastuzumab, with significant increases in immune response after a single dose of the drug.
“ ‘Our study showed, for the first time, that the immune-cell–activating properties of trastuzumab are likely related to the subtypes of breast cancer,’ Varadan said. ‘Knowing this can inform future trials studying the usefulness of adding immunotherapy drugs to trastuzumab.’ “
TNBC has long been considered to be more amenable to immune system-based treatments than other types of breast cancer because it is more immunogenic; that is, relatively high levels of immune cells accumulate within or adjacent to TNBC tumors. These immune cells could be triggered to attack tumors if properly activated. TNBC tumors are also likely to have a higher mutational burden (number of genetic mutations). This is one of the predictors of sensitivity to a type of treatment called immune checkpoint blockade. Drugs known as checkpoint inhibitors block the proteins PD-1 or PD-L1. In cancer, PD-L1 proteins on tumor cells bind to PD-1 proteins on immune T cells and inhibit their tumor-killing activity. Immune checkpoint drugs disable this interaction and enable activation of T cells. These drugs are actively being explored in TNBC in clinical trials.
Women diagnosed with localized breast cancer face difficult decisions with their doctors. What kind of neoadjuvant (before surgery) treatment to choose? Should chemotherapy follow surgery? Based on the subtype of breast cancer, should specific chemotherapy drugs be used? Continue reading…
“From 1973 to 2010 in the U.S., large reductions in breast cancer-specific death hazards were experienced in women diagnosed with invasive breast cancer, a comprehensive analysis of breast cancer survival data now shows.
“Although overall age-adjusted breast cancer mortality rates were stable initially, they decreased by almost one-third, from 33.5% in 1988 to 23.5% in 2010, reported Mitchell Gail, MD, PhD, senior investigator, biostatistics branch, division of cancer epidemiology and genetics, National Cancer Institute, Rockville, Md., and colleagues online in the Journal of Clinical Oncology.
“Improvements were evident in women younger than age 70 years with distant stage at time of diagnosis, as well as in those with local and regional disease. Tumor size usually accounted for more of the improvement in the first 5 years after diagnosis rather than later on, the researchers said.
” ‘Breast cancer mortality rates following diagnosis have been decreasing over four decades, not only in the first five years after diagnosis but thereafter,’ Gail told MedPage Today. ‘Little of the improvement could be explained by changes in tumor size or estrogen-receptor (ER) status over time in women under age 70. This suggests a major contribution from treatment for these women.’ “
Earlier this year, a new treatment option was added to the arsenal for ER-positive breast cancer in postmenopausal women when the U.S. Food and Drug Administration (FDA) approved the combination of letrozole (Femara) and palbociclib (Ibrance). Continue reading…