“The investigational third-generation nonsteroidal oral selective estrogen receptor degrader (SERD) RAD1901 was associated with a 23% objective response rate among 40 heavily pretreated women with estrogen receptor (ER)-positive, HER2-negative breast cancer, according to authors of a phase I dose-escalation and safety cohort study (NCT02338349) presented (abstract 1014) at the 2017 American Society of Clinical Oncology (ASCO) Annual Meeting, held June 2–6 in Chicago.”
“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.”
“NanoString Technologies, Inc. (NASDAQ:NSTG), a provider of life science tools for translational research and molecular diagnostic products, today announced that Humana has issued a positive coverage decision for the Prosigna® Breast Cancer Gene Signature Assay. Humana and its more than 13 million members join other payors now covering Prosigna, collectively representing more than 175 million covered lives throughout the United States.
“This positive coverage decision is in line with updated ASCO guidelines released in February of 2016, wherein Prosigna is considered medically necessary to assess the necessity of adjuvant chemotherapy in ER-positive, HER2-negative, node-negative breast cancer patients, when adjuvant chemotherapy is not precluded due to any other factor.”
“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.”
“GTx, Inc. (GTXI) announced today positive initial data from its ongoing open-label enobosarm Phase 2 clinical trial in women with advanced, estrogen receptor positive (ER+), androgen receptor positive (AR+) breast cancer. The pre-specified threshold for success of the trial was met early in the 9 mg cohort with 9 patients achieving a clinical benefit response at 24 weeks among the first 22 evaluable patients in that cohort, as reported by the Company on November 28, 2016. Clinical Benefit Response (CBR) is defined as a complete response (CR), partial response (PR) or stable disease (SD), as measured by Response Evaluation Criteria in Solid Tumors (RECIST) at 24 weeks of treatment.”
“GTx, Inc. (Nasdaq: GTXI) today announced that enobosarm achieved the pre-specified primary efficacy endpoint in the 9 mg dose cohort from patients in both stage 1 and the ongoing stage 2 of its Phase 2 clinical trial in women with advanced, estrogen receptor positive (ER+), androgen receptor positive (AR+) breast cancer. The primary efficacy endpoint requires at least nine patients (out of a total of 44 evaluable patients) to achieve clinical benefit, defined as either a complete response, partial response or stable disease, as measured by Response Evaluation Criteria in Solid Tumors (RECIST) at 24 weeks of treatment. In this ongoing trial, the efficacy endpoint was achieved in the first 22 confirmed evaluable patients, and the trial will continue enrolling and treating eligible patients with enobosarm until 44 evaluable patients have completed the trial. Enobosarm has been well tolerated among patients treated to date in the 9 mg dose cohort with the majority of adverse events being either grade 1 or 2.”
“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.”