Anti–HER-2 DC1 vaccination is safe and immunogenic for patients with HER-2–positive early invasive breast cancer and ductal carcinoma in situ, according to a randomized trial.
“Cancer immunotherapy aims to sensitize and restore a specific anti-tumor immune response,” Lea Lowenfeld, MD, general surgery resident at University of Pennsylvania Perelman School of Medicine, and colleagues wrote. “Our group has shown that there is a progressive loss of the anti–HER-2 Th1 immune response along the continuum of HER-2–positive breast cancer, and we have developed a HER-2 peptide-pulsed dendritic cell (DC1) vaccine that is uniquely engineered to induce a strong anti–HER-2 immune response.”
The researchers administered the vaccine to 54 women (median age, 55 years; 80.2% white) with HER-2–positive early-stage breast cancer — 84% of whom were postmenopausal — between July 2009 and July 2015.
Lowenfeld and colleagues prepared vaccines for each woman by isolating dendritic cells from patients’ blood and exposing the cells to fragments of HER-2 protein. Researchers administered the vaccination once a week for six weeks via one of three routes: injection directly into the breast (n = 19), into the groin lymph nodes (n = 19) or half into the breast and half into the lymph nodes (n = 16). Lowenfeld and colleagues monitored patients for a minimum of one hour after each weekly vaccination.
All injections were well-tolerated. The vaccination routes did not produce significantly different immune responses (breast, 84.2%; intranodal, 89.5%; both, 66.7%).
The rate of pathologic complete response was higher in patients with DCIS than in those with invasive breast cancer (28.6% vs. 8.3%).
Peripheral anti–HER-2 immune responses were similar in patients with DCIS who did (n = 12) and did not (n = 30) achieve pathologic complete response.
All patients who achieved pathologic complete response experienced an anti–HER-2 CD4 immune response in the sentinel lymph node; quantified response was higher by response repertoire (P = .03) and cumulative response (P = .04).
Adverse events were mild and included injection site reaction, fatigue and chills/rigors.
“This trial showed that DC1 vaccination remained safe and well-tolerated independent of the route of vaccination,” the researchers wrote. “We suggest that the sentinel lymph node may also be evaluated for its immunologic properties, and that future trials may further explore the immune response detected in the sentinel lymph node as an endpoint to better evaluate immune-based therapies.” – by Andy Polhamus
Disclosure: The researchers report no relevant financial disclosures.