Researchers reported a number of important findings in breast cancer treatment at the 2017 Annual Meeting of the American Society of Clinical Oncology:

Targeted treatments used in combination effective in treating certain types of advanced breast cancer

Both abemaciclib and fulvestrant are targeted treatments called CDK4/6 inhibitors; they are designed to interrupt enzymes that promote the growth of cancer cells. The phase lll MONARCH 2 trial showed that abemaciclib, given in combination with fulvestrant, was effective in treating women with ER-positive, HER-2 negative advanced breast cancer whose disease had progressed while being treated with endocrine therapy.

What Patients Need to Know

Progression-free survival (PFS), the length of time that the cancer does not grow or spread, was 16.4 months when abemaciclib and fulvestrant were given in combination, compared to 9.3 months when fulvestrant was given alone. The safety profile of the combination treatment was generally tolerable.

Only modest benefit in adding second drug in treatment of early-stage HER2-positive cancer

The phase lll Aphinity trial showed that the addition of pertuzumab to the standard of care trastuzumab in the treatment of early-stage HER2-positive breast cancer reduced the incidence of developing invasive disease, but only by a small percentage. After three years, 94.1 percent of the women who were treated with the two drugs were free of invasive breast cancer, compared with 93.2 percent who were treated with trastuzumab only.

The rates of serious side effects were low in both groups.

What Patients Need to Know

Pertuzumab and trastuzumab are both targeted treatments that find and attach to HER2-positive cancer cells, slowing or stopping their growth. Researchers are continuing to study the possible long-term benefits of using pertuzumab in combination with trastuzumab.

PARP inhibitor prolonged progression-free survival in BRCA-mutated HER2-negative metastatic breast cancer

PARP is a type of enzyme that helps repair DNA. PARP inhibitors are designed to prevent cancer cells from repairing their damaged DNA; this prevention can cause the cancer cells to die.

When compared with standard single agent chemotherapy treatment, the phase lll study OlympiAD showed that the PARP inhibitor olaparib prolonged progression-free survival (PFS) in women with HER2-negative metastatic breast cancer containing a mutation of the BRCA1 or BRCA2 gene.

What Patients Need to Know

Median PFS was 2.8 months longer and the risk of disease progression or death was 42 percent lower in the group that received olaparib. Olaparib is currently approved by the FDA for the treatment of BRCA-related ovarian cancer.

Immunotherapy in combination with chemotherapy effective in certain types of breast cancer

The phase II I-SPY 2 trial investigated the use of the immunotherapy pembrolizumab, in combination with standard chemotherapy treatment, as neoadjuvant (pre-surgery) treatment for women with locally advanced triple-negative or hormone receptor-positive/HER2-negative breast cancer.

What Patients Need to Know

The results showed that the addition of pembrolizumab to the chemotherapy regimen tripled the rate of “complete pathological response” (absence of all detectable cancer). Due to the positive outcome of this early-stage trial, further research will be conducted.