Final results regarding the addition of dendritic cell vaccines to neoadjuvant chemotherapy in early HER2-negative breast cancer patients

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The purpose of this study is to assess the safety, feasibility, and efficacy of adding dendritic cell vaccines (DCV) to NAC in patients with HER2-negative breast cancer. The findings imply that combining DCV and NAC is safe and boosts tpCR, with PD-L1-negative tumors benefiting the most. DCV alters the tumor microenvironment and triggers cellular and humoral reactions in the peripheral blood, but has no effect on the outcome.

Patients characteristics

39 patients with median age of 49 years old (range, 36–84) diagnosed with non-overexpressing operable Her2 BC who could benefit from NAC and with availability to get enough tumor sample and blood derived monocytes from leukapheresis to elaborate the vaccines. An Eastern Cooperative Oncology Group (ECOG) performance status of 0–1. All patients must have adequate bone marrow status, kidney and liver functions.


Vaccine preparation
PBMCs obtained before and after DCV resuspended in complete culture medium (RPMI 1640 with 10% heat- inactivated human AB serum, 2mM glutamine, 100UI/ml penicillin and 100μg/ml streptomycin) were plated in 96-well plates at 2×105 per well alone or with 2×104 tumor lysate-pulsed DC. After incubation at 37°C and 5% CO2 for 5 days, cells were pulsed with 0.5 μCi/well of [3 H] thymidine for 18 hours and harvested.


All patients received sequential neo-adjuvant chemotherapy (NAC) consisting of four cycles of dose-dense epirubicin plus cyclophosphamide (ddEC) with G-CSF support followed by a second schedule of four cycles each 21 days of docetaxel according to standard protocols.
In addition to the NAC treatment, 39 patients received vaccination with monocyte-derived autologous DC loaded with autologous tumor lysate. The vaccination plan included at least six vaccines being the first one administered between the last ddEC and the first taxane-based cycle. Vaccines were administered intradermally every 3weeks in the first five doses. The sixth dose was administered the day after surgery. When radiation therapy was completed, four vaccines were administered every 2 months and finally, quarterly until the end of the vaccines.


Clinical outcomes
The experimental therapy helped to downstage from mastectomy to conservative surgery in 13.6% of the patients, as compared to none in the control group. After NAC, the total pathological complete response (tpCR) rate was superior among vaccinated patients (28.9% versus 9.1%, absolute increment of 19%).
According to subtype, triple negative (TN) BC patients experienced the highest tpCR (50% for VG versus 30.7% for CG, absolute benefit of 19%), with modest responses for luminal B types (16.6% for vaccinated versus none in CG). Survival
The percentage of patients at 5-year who were alive with disease progression was 12.82% in the vaccinated group versus 14.35% in the control group, whereas after 7 years, 17.08% in the control group and 19.70% in the vaccinated group. At 5- and 7-year follow-up, patients alive in the control group were 90.41% and 87.58%, respectively, and 94.87% and 91.36% in the vaccinated group, respectively.
Treatment-related grade ≧3 toxicities were similar among both groups and only the rate of grade 3 nausea/vomiting was significantly higher in the CG versus the VG (11.3% versus 0%). The most common grade 3 AEs were lymphopenia and asthenia. In the vaccinated group, one patient developed grade 3 hepatic toxicity (4.7%) related to docetaxel. The toxicity related to DCV was mild in all the 39 patients: only one patient developed fever⩾38°C the day of intradermal injection; two patients shown erythema and one more patient showed tenderness at the site of the injection.


The combination of DCV plus NAC is safe and increases tpCR, with a significant benefit among PD-L1-negative tumors. DCV modify tumor milieu and perform cellular and humoral responses in peripheral blood with no impact in outcome.

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Scientific article publishing date 11/6/2021

Immucura identifier BSC21_286EN