“Approximately 5% of patients with sporadic breast cancer harbor mutations in BRCA1 or BRCA2; genes that are involved in the DNA repair process. Several phase I/II clinical studies have shown activity of single agent poly(ADP-ribose) polymerase (PARP) inhibitors in patients with metastatic breast cancer (MBC) and BRCA1/2 mutations. Recently in the randomized phase III OlympiAD trial, the PARP inhibitor olaparib improved progression-free survival (PFS) by 2.8 months over standard chemotherapy in patients with human epidermal growth factor 2 (HER2)–negative MBC and germline BRCA mutations.”
“The PARP inhibitor talazoparib significantly increased progression-free survival (PFS) over physician’s choice of therapy in a randomized phase III trial of patients with advanced breast cancer and a germline BRCA mutation.
“ ‘Talazoparib is a highly potent, dual-mechanism PARP inhibitor. It prevents the repair of DNA damage, and results in cell death,’ said Jennifer K. Litton, MD, of the University of Texas MD Anderson Cancer Center in Houston. A previous phase II study showed encouraging efficacy with the agent in patients with BRCA1/2 mutations, which led to the new EMBRACA trial. Litton presented results of the trial at the 2017 San Antonio Breast Cancer Symposium (SABCS), held December 5–9.”
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…
Last month, the annual American Society of Clinical Oncology (ASCO) meeting took place in Chicago. Thousands of oncologists, patients, and journalists gathered to learn about the most recent developments in cancer research and treatment. Here are some breast cancer highlights from the meeting:
Triple negative breast cancer (TNBC) is considered more responsive to treatment with immune checkpoint drugs than any other type of breast cancer. So far, these drugs have primarily been explored in metastatic TNBC, in combination with chemotherapy. The combination of “anti-PD-L1” and “anti-PD-1” immune checkpoint drugs with chemotherapy has now been examined in early-stage TNBC, in which a breast tumor can be surgically removed after neoadjuvant chemotherapy. Continue reading…
“Pfizer Inc. (NYSE:PFE) today announced Phase 2 data showing that its investigational, dual-mechanism poly ADP ribose polymerase (PARP) inhibitor, talazoparib, demonstrated anti-tumor activity in patients with germline (inherited) BRCA1/2-positive (gBRCA+) advanced breast cancer. Results from the Phase 2 ABRAZO trial were presented during an oral session at the 53rd Annual Meeting of the American Society of Clinical Oncology (ASCO) in Chicago.”
“All 13 newly diagnosed breast cancer patients with BRCA mutations had their tumors shrink significantly when treated with a PARP inhibitor ahead of frontline presurgical chemotherapy in a pilot study at The University of Texas MD Anderson Cancer Center.
“Tumor shrinkage after two months of treatment with the PARP inhibitor talazoparib, measured by ultrasound, ranged from 30 to 98 percent with an average reduction in tumor volume of 78 percent among the 13 patients.”
“Joanne Blum, MD, PhD, breast medical oncologist, director, Hereditary Cancer Risk Program, Baylor Charles A. Sammons Cancer Center, discusses the function of the oral PARP inhibitor talazoparib (BMN 673) in BRCA mutation subjects with locally advanced and/or metastatic breast cancer. Blum says the BRCA mutation works in combination with talazoparib in order to better cut off the appropriate pathways for the tumors.
“Blum said during the phase I trial that looked at talazoparib, patients experienced grade 1 neutropenia, cytopenia and fatigue. Blum added that the toxicities were very mild.”