“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.”
“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.”
“Use of tamoxifen and aromatase inhibitors during and after breast cancer treatment were found to reduce the risk of contralateral breast cancer in a community healthcare setting, according to a study published in JAMA Oncology.
“The authors of the real-world retrospective study found that among estrogen receptor (ER)-positive breast cancer patients who survived at least 5 years, tamoxifen use for 4 years or more prevented an estimated three contralateral breast cancer cases for every 100 women by year 10. This absolute risk reduction is consistent with prior results from tamoxifen clinical trials, according to study authors led by Gretchen L. Gierach, PhD, MPH, of the division of cancer epidemiology and genetics at the National Cancer Institute.”
“At the European Society for Medical Oncology (ESMO) Congress this week, investigators presented data for a new and potentially important drug, ribociclib (Novartis). This oral medication is clearly active in hormone receptor-positive (ER+ or PR+) breast cancer. The findings of the MONALEESA trial were published in the NEJM.
“The main result is that for the most common form of advanced breast cancer, adding ribociclib to letrozole significantly improved progression-free survival (PFS), as compared to adding a placebo. After a year and a half (18 months) in this randomized, controlled clinical trial, PFS among women receiving ribociclib was 63.0%, vs. 42.2% in the placebo arm. That’s a big difference, when you consider that 99% of the patients on the study have stage 4, metastatic breast cancer.”
“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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Written by Emma Shtivelman, PhD and Dov Shiffman, PhD
The American Society of Clinical Oncology (ASCO) meeting of 2016 is behind us, but oncologists, patients, and journalists are still analyzing the most interesting presentations made there. Below, we describe some of the more prominent results in triple negative breast cancer (TNBC), both promising and disappointing.