“Half of patients with metastatic triple-negative breast cancer (TNBC) achieved disease control when treated with the combination of a poly (ADP-ribose) polymerase (PARP) inhibitor and an anti–PD-1 agent, a preliminary prospective study showed.
“Overall, 13 of 46 evaluable patients had objective responses to treatment with niraparib (Zejula) and pembrolizumab (Keytruda). An additional 10 patients had stable disease. Clinical activity was observed in patients beyond those with germline BRCA mutations.”
“Enzalutamide (Xtandi) demonstrated early signs of efficacy in patients with androgen receptor (AR)-positive triple-negative breast cancer (TNBC), according to findings from the phase II MDV3100-11 study published in the Journal of Clinical Oncology.
“A total of 118 patients were enrolled in the single-arm, 2-stage trial, and 78 were evaluable for response. At 16 weeks, the clinical benefit rate (CBR) was 25% (95% CI, 17-33) in the intent-to-treat (ITT) population and 33% (95% CI, 23-45) in the evaluable subgroup. The median progression-free survival (PFS) was 2.9 months (95% CI, 1.9-3.7) in the ITT population and 3.3 months (95% CI, 1.9-4.1) in the evaluable subgroup. Median overall survival (OS) was 12.7 months (95% CI, 8.5 – not yet reached) in the ITT population and 17.6 months (95% CI, 11.6 – not yet reached) in the evaluable subgroup.”
“Updated results of the phase Ib/II ENHANCE1/KEYNOTE-150 study presented at the 2017 San Antonio Breast Cancer Symposium found that the combination of pembrolizumab (Keytruda) and eribulin (Halaven) was associated with a 26.4% objective response rate (ORR) for patients with metastatic triple-negative breast cancer (TNBC).
“In the open-label study, the ORR with the combination for untreated patients with metastatic TNBC (n = 65) was 29.2% (95% CI, 18.6%-41.8%). In a cohort of patients pretreated with 1 to 2 therapies (n = 41), the ORR was 22.0% (95% CI, 10.6%-37.6%). Across all treatment arms, there were 3 complete responses to the combination (2.8%).”
“Treatment with nab-paclitaxel (Abraxane) showed promising improvements in overall survival (OS) and progression-free survival (PFS) compared with standard paclitaxel for patients with metastatic triple-negative breast cancer (TNBC), according to post-hoc findings from the CALGB 40502/NCCTG N063H trial presented at the 2017 San Antonio Breast Cancer Symposium (SABCS).
“For those with TNBC in the phase III trial (n = 201), the median OS with nab-paclitaxel was 21.0 months compared with 15.3 months with standard paclitaxel, representing a 26% reduction in the risk of death. Given the limitations of the post-hoc assessment, these findings were not powered for statistical significance, explained lead investigator Hope S. Rugo, MD. The hazard ratio for the comparison was 0.74 (95% CI, 0.51-1.07).”
“Treatment with IMMU-132 (sacituzumab govitecan) elicited an objective response rate (ORR) of 34 percent in patients with heavily pretreated metastatic triple-negative breast cancer, according to updated findings from a phase 2 study presented at the 2017 San Antonio Breast Cancer Symposium (SABCS).
“In the 110-patient single-arm trial, the ORR was accompanied by stable disease (SD) for 6 months or more in 11 percent of patients, for an overall disease control rate of 45 percent. The median progression-free survival (PFS) with IMMU-132 was 5.5 months and the median overall survival (OS) was 12.7 months.”
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…
“In patients with metastatic triple negative breast cancer (TNBC), turning a nonimmunogenic (“cold”) tumor into an immunogenic (“hot”) tumor appears to be feasible, thereby improving sensitivity to immune therapy with nivolumab (Opdivo).
“In a phase II study of 50 patients with metastatic TNBC who received palliative chemotherapy, priming the immune system with low-dose chemotherapy for 2 weeks or radiation therapy before starting nivolumab resulted in a best objective response rate (ORR) of 24%, announced Marleen Kok, MD, at the 2017 ESMO Congress in Madrid.”
“The randomized phase II LOTUS trial has shown improved progression-free survival with the addition of the AKT inhibitor ipatasertib to paclitaxel in the first-line treatment of metastatic triple-negative breast cancer. These results were reported by Kim et al in The Lancet Oncology. The PI3K/AKT signaling pathway is frequently activated in triple-negative breast cancer.
“In the double-blind trial, 124 patients with unresectable locally advanced or metastatic disease from 44 sites in South Korea, the United States, France, Spain, Taiwan, Singapore, Italy, and Belgium were randomized between September 2014 and February 2016 to receive paclitaxel at 80 mg/m² on days 1, 8, and 15 with either ipatasertib at 400 mg (n = 62) or placebo (n = 62) once daily on days 1 to 21 every 28 days until disease progression or unacceptable toxicity. Stratification factors included tumor PTEN status as determined by immunohistochemistry; deficient expression of PTEN is associated with greater AKT pathway activation. The co-primary endpoints were progression-free survival in the intention-to-treat population and progression-free survival in the PTEN-low population.”
“Sacituzumab govitecan (IMMU-132) was well tolerated and demonstrated early and durable responses in heavily pretreated patients with metastatic triple-negative breast cancer (mTNBC), according to the results of a recent phase I/II study published in the Journal of Clinical Oncology.
“Sacituzumab govitecan is an antibody–drug conjugate that targets Trop-2, which is expressed in more than 90% of TNBCs, by selectively delivering SN-38, the active metabolite of irinotecan. It was granted a breakthrough therapy designation by the FDA in February 2016 for the treatment of patients with mTNBC, following at least 2 treatments for metastatic disease.”