Researchers reported a number of important findings in breast cancer treatment at the 2018 Annual Meeting of the American Society of Clinical Oncology:

Chemotherapy of no additional benefit for certain women with hormone receptor-positive, HER2-negative breast cancer

Results of the phase II TAILORx trial showed that post-surgery chemotherapy can be avoided for women with hormone receptor-positive, HER2-negative, axillary node-negative early-stage breast cancer and a mid-range score of 11-25 on a 21-tumor gene expression assay (the Oncotype DX Breast Recurrence Score). Gene expression assays (tests) analyze the gene activity of breast cancer tumors.

For this group of women, the trial found no improvement in disease-free survival when chemotherapy was added to hormone therapy.

What Patients Need to Know

Approximately 70 percent of hormone receptor-positive, HER2-negative, axillary node-negative breast cancers have a mid-range Oncotype DX Breast Recurrence Score. The TAILORx study shows that chemotherapy (and its side effects) can be avoided in treating this group of women.

Long-term results of TEXT and SOFT trials reported

Compared with tamoxifen and ovarian function suppression, long-term follow-up results of the combined TEXT and SOFT trials indicated that post-surgery treatment with an aromatase inhibitor, combined with ovarian function suppression, reduced the risk of recurrence among premenopausal women with hormone receptor-positive early-stage breast cancer.

The estrogen produced by the ovaries can fuel tumor growth. Ovarian function suppression stops the ovaries from producing estrogen. Aromatase inhibitors block the action of the aromatase enzyme, cutting off the remaining supply of estrogen that can stimulate tumor growth.

What Patients Need to Know

The combined study results also showed that in very young women (age 30 or younger) and women with a high enough risk to receive chemotherapy, ovarian function suppression combined with tamoxifen reduced the risk of invasive recurrence compared with tamoxifen alone.

Shortened duration of trastuzumab treatment shown to be effective

Results of the phase III Persephone trial showed that taking the targeted therapy trastuzumab for 6 months can be as effective as the current standard of 12 months in treating women with HER2-positive, early-stage breast cancer, with fewer cardiac side effects.

What Patients Need to Know

The four-year disease-free survival rate was 89.4 percent with 6 months of trastuzumab therapy and 89.8 percent with 12 months of therapy. Only 4 percent of the women in the 6-month group of the trial stopped treatment with trastuzumab early due to cardiac problems, compared with 8 percent in the 12-month group.

Priority Review granted to investigational drug for treatment of triple-negative breast cancer

A Priority Review designation means FDA’s goal is to take action on an application within 6 months. Based on data from a phase I/II trial, the FDA has granted a Priority Review to the investigational drug sacituzumab govitecan for the treatment of women with metastatic triple-negative breast cancer who have received at least two prior therapies.

What Patients Need to Know

The FDA’s Priority Review process applies to drugs that are considered a significant improvement over the available alternatives. If approved, sacituzumab govitecan would be the first antibody-drug conjugate (a targeted therapy designed to kill cancer cells while sparing healthy cells) approved for the treatment of metastatic triple-negative breast cancer.