“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.”
“Previously the drug was approved as second-line monotherapy for women failing anti-estrogen therapy, and as second-line combination therapy with palbociclib (Ibrance). It was first approved by the FDA in 2002.”
“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.”
Mutations in the gene that encodes the KRAS protein are frequently encountered in various human cancers. They are found in about 30% of non-small cell lung cancers (NSCLCs), making KRAS the single most common gene mutated in this cancer. The rate of KRAS mutations in other cancers, such as pancreatic or colorectal, is even higher.
A mutant KRAS protein that is always in the “on” position activates many signaling pathways, many of which lead to unrestrained growth and proliferation of cancer cells. This makes KRAS an appealing treatment target. However, challenges abound, and researchers are exploring several different approaches to treating KRAS-mutant cancers.
Unlike mutations in proteins known as receptor tyrosine kinases, like EGFR or ALK, mutated KRAS is a very difficult protein to target with cancer drugs. (So much so that the National Institutes of Health (NIH) has undertaken a special effort to intensify the effort towards successful targeting of mutant KRAS, known as the RAS Initiative.) Continue reading…
“Cancers driven by the RAS oncogene are aggressive and difficult to treat, and thus far precision drugs haven’t been able to target the mutant RAS gene successfully.
“But in a presentation at the American Association for Cancer Research Annual Meeting on Monday, April 3, 2017 at 10:30 a.m., in Washington DC, Dana-Farber Cancer Institute scientists said a number of patients in a small study with RAS-driven lung, ovarian, and thyroid cancers got long-term clinical benefit from a combination of two drugs that targeted molecular pathways controlled by the RAS gene.
” ‘Between one-quarter and one-third of patients got long-term clinical benefit,’ said Geoffrey Shapiro, MD, PhD, director of Dana-Farber’s Early Drug Development Center. ‘Several patients were on the drugs for more than a year, and one patient has been on treatment for two and a half years. And these were heavily-treated patients without many options.’ ”
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…
“Palbociclib can help slow the progression of advanced breast cancer, according to a study published in the Nov. 17 issue of the New England Journal of Medicine.
“Richard Finn, M.D., an assistant professor of medicine at the University of California, Los Angeles, and colleagues tested palbociclib-letrozole as a first-line treatment for estrogen-receptor (ER)-positive, human epidermal growth factor receptor 2 (HER2)-negative advanced breast cancer. They randomly assigned 666 women to receive the drug combination or letrozole alone, and followed them for up to three years.
“At that point, the researchers found that 43.7 percent of women in the palbociclib group had either died or seen their cancer progress. That compared with 61.7 percent of women on letrozole alone. Women on the drug combination typically remained progression-free for 24.8 months, versus 14.5 months for women on letrozole. One of the most common side effects—seen in two-thirds of women in this study—was neutropenia.”
“Results of two pivotal breast cancer trials reported at the 2016 ASCO Annual Meeting confirmed the practice-changing findings that resulted from earlier findings.
“The phase III PALOMA-2 trial confirmed results from the smaller, open-label phase II PALOMA-1 trial that led to the U.S. Food and Drug Administration (FDA) approval of the cyclin-dependent kinase 4/6 inhibitor palbociclib (Ibrance). The drug was approved in combination with letrozole for the first-line treatment of metastatic disease.
“ ‘These data represent the longest front-line improvement in median progression-free survival seen to date in women with advanced estrogen receptor (ER)-positive breast cancer,’ said Dennis Slamon, MD, Director of Clinical/Translational Research and Professor of Medicine at the University of California, Los Angeles, and Director of the Revlon/UCLA Women’s Cancer Research Program.”
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