Dendritic cell vaccination, antiestrogen therapy boosts pathologic complete response in breast cancer

Combined neoadjuvant antiestrogen therapy and anti–HER-2 dendritic cell vaccination increased pathologic complete response rate and decreased subsequent breast events among women with ER-positive, HER-2–positive breast cancer, according to study results presented during the plenary session of the Society for Surgical Oncology Annual Cancer Symposium.

“Many preclinical studies have shown extensive bidirectional crosstalk between the HER-2 and ER-signaling pathways, activating each other and leading to enhanced cell proliferation and survival,” Lea Lowenfeld, MD, general surgery resident at University of Pennsylvania, told HemOnc Today. “The results of this study further support the increasing move toward individualized combination targeted therapies.”

Lea Lowenfeld, MD

Prior clinical trials have linked neoadjuvant vaccination with HER-2–pulsed dendritic cells to higher rate of pathologic complete response in women with ER-negative breast cancer.

Lowenfeld and colleagues sought to determine the effect of combined antiestrogen therapy and anti–HER-2 dendritic cell vaccination on clinical and immune responses for women with breast cancer.

The researchers assigned the neoadjuvant vaccine to 78 women with HER-2–positive ductal carcinoma in situ. This cohort included 34 women with ER-negative breast cancer. Of the other ER-positive women, 24 did not receive antiestrogen therapy and 20 received concurrent antiestrogen therapy.

The researchers assessed pathologic complete response at the time of surgical resection and followed women to detect subsequent breast events for a minimum of 1 year.

Median follow-up was 5 years.

Eleven patients with ER-negative breast cancer (32.4%) achieved a pathologic complete response.

Of ER-positive patients, a significantly greater proportion of those who received concurrent antiestrogen therapy achieved a pathologic complete response (25% vs. 4.2%; P < .01).

Further, only women with ER-positive breast cancer who did not receive antiestrogen therapy experienced subsequent ductal carcinoma in situ or invasive breast cancer (n = 4; 16.7%).

Each cohort experienced a significant immune response after vaccination (P < .01). However, there were no significant differences in immune responses before or after vaccination by cohort.

These findings warrant further investigation in randomized controlled trials, according to Lowenfeld.

“Cancer treatments can be used in logical combinations to improve outcomes,” Lowenfeld said. “Our group has ongoing work — both preclinical studies and clinical trials — examining the effects of different combination therapies.” – by Cameron Kelsall

Reference:

Lowenfeld L, et al. Abstract 1. Presented at: Society for Surgical Oncology Annual Cancer Symposium; March 2-5, 2016; Boston.

For more information:

Lea Lowenfeld, MD, can be reached at lea.lowenfeld@uphs.upenn.edu.

Disclosure: Lowenfeld reports no relevant financial disclosures. HemOnc Today could not confirm the other researchers’ relevant financial disclosures at the time of reporting.