HER2 Vaccine Research Articles

Abstract 5296: Enhancing the strength and durability of vaccine-induced anti-tumor immunity with CD27 agonism of CD4+ T cells

Abstract Despite encouraging early phase clinical trials, decades of research have yet to yield effective cancer vaccine immunotherapies. To determine potential markers for success, we performed a follow-up study of a HER2-pulsed dendritic cell cancer vaccine Phase I trial performed in advanced HER2+ cancer patients. Surprisingly, we found that all treated patients were alive at over 18 years post-treatment. These patients still possessed significant HER2-specific memory T cell responses, typified by CD27 expression. The expansion of HER2-specific CD27+ memory T cells was also observed in patients from a separate clinical trial, who received a HER2-expressing viral vaccine. To validate these clinical responses, we vaccinated human CD27 transgenic mice with a HER2 viral vector again observing HER2-specific CD27+ memory T cells, suggesting the significance of this axis in eliciting and maintaining effective vaccine-specific memory T cell responses. We hypothesized that CD27 expression was not just a marker of memory T cells, but represented a critical activation pathway during memory formation. To determine the potential impact of CD27 agonism in vaccination, we combined HER2 vaccination with an anti-CD27 agonist antibody (Varlilumab). The combination treatment elicited a robust increase in HER2-specific CD4+ memory T cell responses that was maintained for at least 300 days post-vaccination. Using therapeutic HER2 vaccination in combination with anti-CD27 of HER2+ tumor bearing mice, we show significantly increased anti-tumor efficacy and further enhancement in combination with PD1 inhibition. The anti-tumor response was triggered by anti-CD27 antibody during the vaccine priming phase, which enhanced HER2-specific CD4+ T cells. Critically, we found that HER2 specific CD4+ T cell responses allowed for anti-tumor responses that persisted after CD8+ T cell depletion, indicating a direct role for antigen-specific CD4+ T cells independent of CD8+ T cells. Collectively, our results support a central role for antigen-specific CD27+ CD4+ T cells in cancer vaccination. These data support the addition of CD27 agonism to improve the therapeutic index of cancer vaccines and potentially enhance responses to immune checkpoint blockade in refractory cancers. Citation Format: Bin-Jin Hwang, Erika Crosby, Timothy Trotter, Li-Chung Tsao, Tao Wang, Congxiao Liu, Xiao Yang, Gangjun Lei, Junping Wei, Xingru Ma, Bushanqing Liu, Amy Hobeika, Michael Morse, Tibor Keler, Li-Zhen He, Herbert Kim Lyerly, Zachary Hartman. Enhancing the strength and durability of vaccine-induced anti-tumor immunity with CD27 agonism of CD4+ T cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5296.

AE37 HER2-targeted vaccine in the prevention of breast cancer recurrence: A mini narrative review of current evidence

Breast cancer remains a significant global health challenge, necessitating innovative therapeutic strategies. This review synthesizes findings from multiple studies investigating the safety profile and efficacy of the AE37 human epidermal growth factor receptor 2 (HER2)-targeted vaccine, offering insights into its potential role in breast cancer immunotherapy. A systematic search of electronic databases, including PubMed, MEDLINE, Scopus, and Web of Science, was conducted to identify relevant articles published up to October 2023. The search strategy utilized a combination of keywords, including “AE37 HER2 vaccine,” “breast cancer recurrence prevention,” and related terms. Boolean operators (AND, OR) were employed to refine the search. The AE37 vaccine exhibited a favorable safety profile across all studies, with minimal adverse effects reported. Efficacy outcomes varied, with promising trends observed in specific breast cancer subgroups, such as advanced-stage, HER2 under-expressed, and triple-negative breast cancer patients. Subgroup analyses suggested potential benefits, emphasizing the need for precise patient stratification. While the AE37 HER2-targeted vaccine demonstrates a promising safety profile and potential efficacy in specific breast cancer subgroups, an understanding requires addressing identified limitations and advancing research in nuanced directions. This paper provides a foundation for navigating the complex landscape of breast cancer immunotherapy with the AE37 vaccine.

A multicenter phase II study of vaccines to prevent recurrence in patients with HER-2–positive breast cancer.

532 Background: Patients (pts) with early stage HER2-positive breast cancer are commonly treated with neoadjuvant HER2-targeted therapy. Pts who have residual invasive disease have a less favorable outcome and increased risk of recurrent disease than pts with a complete pathologic response (pCR). It also has been observed that pts who do not achieve a pCR have low or absent anti-HER-2 CD4 Th1 responses. We hypothesized that correcting anti-HER-2 CD4 Th1 response using vaccines will be safe, induce anti-tumor immunity in HER2-positive breast cancer and reduce the risk of recurrence. We conducted a multi-center, phase 2, randomized study to determine the safety, immunogenicity and recurrence free survival of two HER2 vaccines (multivalent anti-oncodriver DNA vaccine (WOKVAC) or HER-2-pulsed dendritic cell vaccine (DC1)). Methods: Pts with HER2-positive early breast cancer were eligible if they had residual invasive disease at surgery after receiving neoadjuvant chemotherapy plus HER2-targeted therapy. Patients were randomly assigned in a 1:1 ratio, with stratification according to residual cancer burden (RCB) (1+2 vs 3) to receive adjuvant HER2 vaccination with either DC1 or WOKVAC. For the initial vaccination phase, DC1 was delivered via US guided inguinal lymph node administration, weekly x 6 weeks and WOKVAC was given intradermally on weeks 1, 4, and 7. Booster vaccines were given at months 6, 9 and 12. The primary end point is to evaluate the safety and tolerability of each vaccine and assess immune response rate as measured by ELISPOT. Each treatment arm will be assessed separately. Secondary endpoints include recurrence-free survival. Exploratory analyses include the assessment of prognostic and predictive biomarkers including circulating tumor cells, serum HER2 levels, and other immune correlative biomarkers. Here we are reporting the initial safety results. Results: Total of 110 eligible pts (55 WOKVAC vs 55 DC1) were enrolled from 2/2018 to 12/2022 and received at least one dose of treatment and 38 pts pending completion of the booster phase. Most pts had clinical stage II/III 56/35 (82%) and 50% had positive node disease at diagnosis. 82% had hormone receptor positive disease. 37/38/8 patients had RCB 1/2/3. For patients without known RCB status, ypTNM was used to randomize (yp stage I/II/III = 13/13/1 pts). The most frequently observed treatment related adverse events (TRAE) were injection site pain/reaction (38%) and chills (34%), fever (25%) and fatigue (40%) for DC1 arm. For WOKVAC, the most common toxicities included injection site reaction (68%) and fatigue (37%). All of these were grade 1 and 2. Nine patients had events including new primary cancer (1), local recurrence (2), metastatic disease recurrence (6). Conclusions: Both DC1 and WOKVAC HER2 vaccines were well tolerated without significant toxicities. Updated results will be presented at the meeting including correlatives. Clinical trial information: NCT03384914 .

Abstract 696: Sensitizing breast cancers to immune checkpoint inhibitors through CD27 agonism and vaccination against tumor-associated antigen

Abstract Project objective: Despite the recent revolution in immune checkpoint inhibitors (ICIs), only modest improvement in overall survival and likely caused by not enough potent cellular immunity among BC patients. Our lab has been focus on inducing cellular immunity against HER2+ BC through vaccination against the tumor-associated antigen HER2. Approximately 20 years ago, we performed an experimental pilot study by administrating HER2 peptide and recombinant protein pulsed dendritic cells (DC vaccine) to six patients with refractory HER2+ advanced or metastatic (stage II (≥ 6 +LN), III, or stage IV) BC. We followed the patients on 2019 found that all of the six patients were still alive, 18 years after vaccination. Their blood sample were analyzed with cytometry by time-of-flight (CyTOF) and found there is a significantly increased presence of CD27 expressing memory T cells in response to HER2 peptide stimulation. Recent report on the SARS-CoV2 mRNA vaccine also suggested that CD27 expressing memory T cells plays a critical role in long-lasting cellular immunity against SARS-CoV2 infection. Therefore, we hypothesized that CD27 plays a critical role in cellular immunity against BC, and the stimulation of CD27 expressing T cells with mAb targeting CD27 significantly increase the cellular immunity triggered by vaccination against tumor-associated antigen. Results: We recapitulate the rise of CD27+ antigen specific T cells among the vaccinated patients using a transgenic mouse model expressing human CD27. When combined the adenoviral-vector based HER2 (Ad-HER2) vaccination with a single dose of human aCD27 antibody (Varlilumab), we found there is a robust increase in the HER2 specific T cells compared to vaccination alone, especially CD27+CD44+ memory CD4 T cells, even after 120 days post vaccination. Using an ICI-insensitive syngeneic HER2+ BC models, we found 50% of mice in the combination group of aCD27 antibody plus Ad-HER2 showed total tumor regression by the end of study. When combined with anti-PD1 antibody, the combination of AdHER2 and Varlilumab leads to total tumor regression in 90% of tumor bearing mice with syngeneic HER2+ BC, indicating that the vaccination against tumor associated antigen HER2 plus anti-CD27 antibody sensitized ICI-insensitive HER2+ BC toward ICI. Conclusions: Our data demonstrates that the administration of anti-CD27 antibody significantly increase the long term presence of CD27+ antigen specific memory T cells after vaccination against tumor associated antigen HER2. As consequence, combination of anti-CD27 with HER2 sensitized the immune unresponsive breast cancer toward anti-PD1 antibody. Our study suggests that the vaccination against tumor-associated antigen with mAb targeting CD27 leads to the robust cellular immunity, which is required for successful ICIs against breast cancer. Citation Format: Bin-Jin Hwang, Erika Crosby, Timothy Trotter, Li-Chung Tsao, Tao Wang, Xiao Yang, Herbert Kim Lyerly, Zachary Hartman. Sensitizing breast cancers to immune checkpoint inhibitors through CD27 agonism and vaccination against tumor-associated antigen [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 696.

NextHERIZON: A phase 2 study of HER-Vaxx, a HER2-targeting peptide vaccine, in combination with chemotherapy or pembrolizumab in patients with HER2 metastatic or advanced gastric/gastroesophageal adenocarcinoma that progressed on or after trastuzumab treatment.

TPS481 Background: HER-Vaxx is a B-cell peptide vaccine composed of a fusion of 3 epitopes from the extracellular domain of HER2/neu conjugated to CRM197 with the adjuvant Montanide. Results from a phase 1b study revealed that active immunization with HER-Vaxx was well tolerated and induced HER2-dose dependent immune responses corresponding to tumor reduction in advanced gastric cancer (GC) or gastroesophageal adenocarcinoma (GEA) (Wiedermann, 2021). A phase 2 study, HERIZON, comparing HER-Vaxx plus standard chemotherapy or chemotherapy alone is currently enrolling. Pre-clinical data demonstrated a synergistic effect with combination of HER2 and PD-1 vaccines and 90% tumor growth inhibition (Kaumaya, 2020). Ramucirumab plus paclitaxel is an approved second-line treatment for patients with GC or GEA who have failed first-line treatment chemotherapy or trastuzumab (TRA) (Wilke, 2014). The nextHERIZON study seeks to evaluate the clinical benefit of adding HER-Vaxx to ramucirumab plus paclitaxel or pembrolizumab, following progression on TRA. Methods: nextHERIZON is phase 2, open-label, non-comparative, double arm, 2-stage design study in patients with confirmed AGC and HER2 overexpression following progression on or after TRA. Arm assignment depends on prior PD-1/PD-L1 inhibitor treatment. Arm 1 will receive HER-Vaxx + ramucirumab and paclitaxel. Arm 2 will receive HER-Vaxx + pembrolizumab. Up to 55 patients will be enrolled in each arm which includes a safety run-in phase. Arms will be analyzed independently. The key inclusion criteria are: patients ³ 18 year of age; ECOG 0 or 1; minimum life expectancy of 3 months; progressed on or after TRA; confirmed HER2 overexpression; at least one measurable lesion; adequate hematologic and organ function. Key exclusion criteria include previous treatment with trastuzumab-deruxtecan or any other anti-HER2 therapy other than trastuzumab. Arm 2 excludes prior therapy with anti- PD-1, PD-L1 or PD-L2 agents. The co-primary endpoints are safety and objective response rate (RECIST 1.1). Secondary objectives are efficacy and survival measures. HER-Vaxx is administered by intramuscular (IM) injection on Day 1, Day 15, and Day 29 and on Day 1 of each 2nd or 3rd cycle depending on arm. Dose-limiting toxicity (DLT) window is 29 days on treatment. Tumor assessment is evaluated at Day 43 then every 6 weeks until progression or withdrawal. This study is currently enrolling patients in Australia and US (Q1 2023). Clinical trial information: NCT05311176 .

HERIZON: A phase 2 study of HER-Vaxx (IMU-131), a HER2-targeting peptide vaccine, plus standard of care chemotherapy in patients with HER2-overexpressing metastatic or advanced gastric/GEJ adenocarcinoma— Overall survival analysis.

289 Background: Active immunization with the B-lymphocyte stimulating HER2 vaccine, HER-Vaxx (IMU-131), has shown clinical response correlated with HER2-specific antibodies (Wiedermann et. al., Clinical Cancer Research, 2021). The HER-Vaxx HERIZON study is based on the landmark ToGA study (Bang et. al., The Lancet, 2010) and included patients with HER2/neu over-expressing metastatic or advanced gastric/GEJ adenocarcinoma who were naïve to HER2 therapy. Methods: Thirty-six patients were randomized to either HER-Vaxx plus standard chemotherapy or standard chemotherapy alone. The primary endpoint was overall survival (OS). HER-Vaxx plus chemotherapy treated patients received 50 µg dose of HER-Vaxx by intra-muscular injection at Days 0, 14, 35, 77 and every 63 days until disease progression. Both groups received chemotherapy starting at Day 0 and then every 21 days for a maximum of 6 cycles or until disease progression. Standard chemotherapy consisted of cisplatin + 5FU or capecitabine, or oxaliplatin + capecitabine. Statistical analysis pre-specified a 1-sided false positive probability of 0.10. Results: Of 36 patients randomized (19 treated with HER-Vaxx plus chemotherapy and 17 with chemotherapy alone), 32 patients had a survival event (15 and 17 respectively) at the time of final analysis. All patients received oxaliplatin + capecitabine chemotherapy. Analysis showed a 42% survival benefit for patients treated with HER-Vaxx plus chemotherapy compared to chemotherapy alone. This translated into an OS HR of 0.580 (80% 2-sided CI: 0.362, 0.927) with a statistically significant p-value of 0.066. The median OS for patients receiving HER-Vaxx plus chemotherapy was 13.9 (7.5, 14.3) months, compared to 8.3 (6.0, 9.6) months in patients treated with chemotherapy alone. Median duration of response was 30 vs 19 weeks in favor of the HER-Vaxx arm. There was no difference in safety between the two treatment arms, indicating HER-Vaxx does not add toxicity to standard chemotherapy. HER-Vaxx induced persistent HER2 specific antibodies which correlated with clinical response. Additional response parameters including DOR and biomarker data will be presented at the meeting. Conclusions: These data demonstrate that in patients with HER2 over-expressing gastric/GEJ cancer active HER2 immunization with HER-Vaxx is safe and provides relevant clinical benefit over standard of care chemotherapy. Clinical trial information: NCT02795988 .

74MO HERIZON overall survival results: A study of IMU-131, a HER2 targeting peptide vaccine, plus standard of care chemotherapy in patients with HER2 overexpressing metastatic or advanced gastric/GEJ cancer

Active immunization with the B-lymphocyte stimulating HER2 vaccine, IMU-131 (HER-Vaxx), has shown clinical response correlated with HER2-specific antibodies (Wiedermann et. al., Annals of Oncology, 2019). The IMU-131 HERIZON study is based on the landmark ToGA study (Bang et. al., The Lancet, 2010) and included patients with HER2/neu overexpressing metastatic or advanced gastric/GEJ cancer who were naïve to HER2 therapy.

A newly discovered PD-L1 B-cell epitope peptide vaccine (PDL1-Vaxx) exhibits potent immune responses and effective anti-tumor immunity in multiple syngeneic mice models and (synergizes) in combination with a dual HER-2 B-cell vaccine (B-Vaxx)

ABSTRACT Blockade of checkpoint receptors with monoclonal antibodies against CTLA-4, PD-1 and PD-L1 has shown great clinical success in several cancer subtypes, yielding unprecedented responses albeit a significant number of patients develop resistance and remain refractory. Both PD-1/PD-L1 and HER-2 signaling pathway inhibitors have limited efficacy and exhibits significant toxicities that limit their use. Ongoing clinical studies support the need for rationale combination of immuno-oncology agents to make a significant impact in the lives of cancer patients. We introduce the development of a novel chimeric PD-L1 B-cell peptide epitope vaccine (amino acid 130–147) linked to a “promiscuous” T cell measles virus fusion (MVF) peptide (MVF-PD-L1(130); PDL1-Vaxx) or linked to tetanus toxoid (TT3) TT3-PD-L1 (130) via a linker (GPSL). These vaccine constructs are highly immunogenic and antigenic in several syngeneic animal models. The PD-L1 vaccines elicited high titers of polyclonal antibodies that inhibit tumor growth in multiple syngeneic cancer models, eliciting antibodies of different subtypes IgG1, IgG2a, IgG2b and IgG3, induced PD-1/PD-L1 blockade, decreased proliferation, induced apoptosis and caused ADCC of tumor cells. The PDL1-Vaxx induces similar inhibition of tumor growth versus the standard anti-mouse PD-L1 antibody in both syngeneic BALB/c and C57BL/6J mouse models. The combination of PDL1-Vaxx with HER-2 vaccine B-Vaxx demonstrated synergistic tumor inhibition in D2F2/E2 carcinoma cell line. The anti-PDL1-Vaxx block PD-1/PD-L1 interaction and significantly prolonged anti-tumor responses in multiple syngeneic tumor models. The combination of HER-2 vaccine (B-Vaxx) with either PDL1-Vaxx or PD1-Vaxx demonstrated synergistic tumor inhibition. PDL1-Vaxx is a promising novel safe checkpoint inhibitor vaccine.

HER2-Displaying M13 Bacteriophages induce Therapeutic Immunity against Breast Cancer.

Simple SummaryThe high incidence and death rates of breast cancer make the development of new therapies an urgent need. The introduction into the clinic of the anti-HER2 monoclonal antibody trastuzumab considerably improved the overall survival and time-to-disease progression of patients with HER2-positive breast cancer. However, many patients do not benefit from it because of resistance to therapy. Cancer vaccines, by inducing into the patient an anti-cancer specific immunity, might represent an alternative immunotherapeutic approach, but despite promises, so far no anti-HER2 cancer vaccine has been approved for human use. In this study, we propose therapeutic phage-based vaccines, against HER2 and its aggressive isoform Δ16HER2, able to elicit a protective immunity and potentially capable of preventing relapse in HER2-positive breast cancer patients, even in those who develop trastuzumab resistance.The advent of trastuzumab has significantly improved the prognosis of HER2-positive (HER2+) breast cancer patients; nevertheless, drug resistance limits its clinical benefit. Anti-HER2 active immunotherapy represents an attractive alternative strategy, but effective immunization needs to overcome the patient’s immune tolerance against the self-HER2. Phage display technology, taking advantage of phage intrinsic immunogenicity, permits one to generate effective cancer vaccines able to break immune tolerance to self-antigens. In this study, we demonstrate that both preventive and therapeutic vaccination with M13 bacteriophages, displaying the extracellular (EC) and transmembrane (TM) domains of human HER2 or its Δ16HER2 splice variant on their surface (ECTM and Δ16ECTM phages), delayed mammary tumor onset and reduced tumor growth rate and multiplicity in ∆16HER2 transgenic mice, which are tolerant to human ∆16HER2. This antitumor protection correlated with anti-HER2 antibody production. The molecular mechanisms underlying the anticancer effect of vaccine-elicited anti-HER2 antibodies were analyzed in vitro against BT-474 human breast cancer cells, sensitive or resistant to trastuzumab. Immunoglobulins (IgG) purified from immune sera reduced cell viability mainly by impairing ERK phosphorylation and reactivating retinoblastoma protein function in both trastuzumab-sensitive and -resistant BT-474 cells. In conclusion, we demonstrated that phage-based HER2 vaccines impair mammary cancer onset and progression, opening new perspectives for HER2+ breast cancer treatment.

Phase II trial to evaluate immune-related biomarkers for pathological response in stage II-III HER2-positive breast cancer receiving neoadjuvant chemotherapy with subsequent randomization to multi-epitope HER2 vaccine versus placebo in patients with residual disease post-neoadjuvant chemotherapy.

TPS610 Background: Several studies demonstrated worsening disease-free survival in patients who failed to achieve complete pathological response after neoadjuvant chemotherapy (NAC), particularly in HER2-positive (HER2+) breast cancer. Despite the recent approval of trastuzumab emtansine (T-DM1) in patients with residual disease after NAC approximately 12% of patients still develop recurrent and metastatic disease. TPIV100 is a multi-epitope vaccine that includes a pool of 4 degenerate HER2-derived HLA-DR epitopes, which activate CD4 helper T cells, admixed with GM-CSF. In our previous phase I trial this vaccine was shown to be safe in combination with trastuzumab in stage II-III HER2+ breast cancer after completion of standard of care chemotherapy. Furthermore, this vaccine also generated robust long-lasting T-cell immune responses and antibody immunity against HER2. Methods: This trial is a multi-center, randomized, placebo-controlled, phase II trial of TPIV100 in combination with T-DM1 in stage II-III HER2+ breast cancer patients with residual disease after NAC. This trial is currently opened through the ACCRU consortium. Eligible patients include those with stage II-III HER2+ with residual disease, in the breast and/or lymph nodes, after trastuzumab ± pertuzumab-based NAC, with ECOG PS ≤ 2 and adequate organ function. Patients with baseline left ventricular ejection fraction < 50%, history of trastuzumab-related cardiac toxicity, myocardial infarction or stroke < 6 months, history of congestive heart failure, autoimmune disease, immunocompromised patients with known HIV or those on chronic steroid, hypersensitivity to GM-CSF, and other active malignancy < 3 years are excluded. TPIV100 or placebo, in combination with GM-CSF, will be given concurrently with T-DM1. To ensure that TPIV100 in combination with T-DM1 is safe, there is a run-in phase with 20 patients treated with the combination. If there is no significant dose-limiting toxicity observed in the run-in phase, the trial will be expanded to the randomized phase II portion, which will include 240 patients. Eligible patients will be randomized in a 2:1 fashion with ER/PR as a stratification factor. The primary endpoint is invasive disease-free survival, and the secondary endpoint includes immunogenicity of TPIV100 as assessed by IFN-g ELIspot analysis. Correlative studies include assessment of helper T-cell response distribution (including Th1, Th2, Th17, Tfh), HER2-specific antibody immunity, and HLA genotype. Currently, 20 patients in the run-in phase have been enrolled. Enrollment to the randomized phase II portion is expected to begin in March 2022. Clinical trial information: NCT04197687.

Abstract OT1-16-01: A multicenter phase II study of vaccines to prevent recurrence in patients with HER-2 positive breast cancer

Abstract Background: HER2-positive breast cancer patients are commonly treated with neoadjuvant therapy including HER2-targeted therapy. Patients who have residual invasive disease have less favorable outcomes with an increased risk of recurrent disease than patients with complete pathologic response (pCR). It has also been observed that these non-pCR patients have low or absent anti-HER-2 CD4 Th1 responses. We hypothesized that correcting the anti-HER-2 CD4 Th1 response using vaccines will increase interferon gamma production which we have shown is a potent inducer of apoptosis and senescence in HER2-positive breast cancer. This study will be evaluating safety and immunogenicity of two vaccines (multivalent anti-oncodriver DNA vaccine (WOKVAC) or HER-2-pulsed dendritic cell vaccine (DC1)). Methods: This is a multi-center, phase 2, randomized study to determine the safety and tolerability of HER2 vaccines (DC1 and WOKVAC), assess immunogenicity, and evaluate recurrence free survival. Patients with HER2-positive early breast cancer (stage I-III) are eligible if they have residual invasive disease in the breast or axilla at surgery after receiving neoadjuvant chemotherapy plus HER2 -targeted therapy. Patients are randomly assigned in a 1:1 ratio to receive 1 of 2 adjuvant HER2 vaccines, either DC1 or WOKVAC for 1 year. A permuted-block randomization scheme was used with stratification according to residual cancer burden (RCB) (1+2 vs 3). The primary end points are safety and immunogenicity (immune response rate measured by ELISPOT). Each treatment arm will be assessed separately. Any statistical comparison between arms is purely exploratory, as this study is neither designed nor powered for comparative hypotheses. Secondary endpoints include recurrence-free survival. Exploratory analyses include the assessment of prognostic and predictive biomarkers including circulating tumor cells, serum HER2 levels, and other immune markers. The enrollment began in 2018 and we plan to accrue the total of 110 patients. ClinicalTrials.gov Identifier: NCT03384914 Citation Format: Hyo S Han, Mary Disis, Robert Wesolowski, Carla Fisher, Shipra Gandhi, Nancy Chan, William Gwin, Keerthi Gogineni, Rosemarie Mick, Christina Sierra Rodriguez, Deanna Hogue, Hien Liu, Ricardo Costa, Brian Czerniecki. A multicenter phase II study of vaccines to prevent recurrence in patients with HER-2 positive breast cancer [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr OT1-16-01.

Abstract OT1-01-06: A pilot study utilizing a HER2 directed dendritic cell vaccine during neoadjuvant therapy of HER2+ breast cancer

Abstract Background: During the natural progression of early breast cancer, it has been demonstrated that the protective host immune response against HER2 is lost early on. Using a type 1 dendritic cell (DC1) vaccine loaded with HER2 peptides has been shown to be effective in restoring anti HER2 immune responsiveness and can lead to regression of very early non-invasive breast cancers. Prior investigations conducted by our group has suggested DC vaccines may sensitize cancers to subsequent systemic chemotherapy, and the Geparnuevo trial also suggested a prechemotherapy dosing with checkpoint therapy may improve pathologic complete response (pCR) rates in TNBC. We launched a pilot study to demonstrate safety, feasibility, and preliminary efficacy of administering the DC1 HER2 vaccine for 3 weeks prior to the initiation of neoadjuvant systemic therapy for stage II-III ER-HER2+ breast cancer. Methods: This single site study is a pilot design with a safety run in phase (n = 12) followed by an expansion cohort of 18 patients. Patients with stage II-III ER-HER2+ breast cancer who are eligible to receive neoadjuvant HER2 based chemotherapy (TCHP) can enroll. The safety run in evaluates two schedules of DC1 vaccination (ARM A = once weekly x 3 weeks and ARM B = twice weekly x 3 weeks) and will enroll six patients in each arm. After the first 3 weeks of DC1 neoadjuvant chemotherapy will be administered using standard docetaxel, carboplatin, trastuzumab, and pertuzumab given intravenously once every 3 weeks for 6 cycles. Booster vaccines will be given at weeks 25, 56, 80, and 104 and immune monitoring will be performed at these timepoints. The safety run in will evaluate safety using CTCAE 4.03 criteria along with the immunogenicity of each arm measured by ELISPOT. The arm with the best immune response at 3 weeks will be selected to proceed forward during the expansion cohort using an endpoint of pCR. Secondary endpoints will be recurrence free survival rate at 3 years and immune response. The pilot design is hypothesis generating but is likely able to detect a significant difference in pCR if the true rate is 75% assuming a historical rate of 55%. Accrual to the safety run in phase is complete and the expansion phase is underway using the twice weekly vaccination schedule. Citation Format: Hatem Soliman, Deanna Hogue, Hyo Han, Hung Khong, Ricardo Costa, Avan Armaghani, Axia Soyano Muller, Nazanin Khakpour, Marie C Lee, John Kiluk, Brian Czerniecki. A pilot study utilizing a HER2 directed dendritic cell vaccine during neoadjuvant therapy of HER2+ breast cancer [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr OT1-01-06.

Elimination of Osteosarcoma by Necroptosis with Graphene Oxide-Associated Anti-HER2 Antibodies.

The prognosis for non-resectable or recurrent osteosarcoma (OS) remains poor. The finding that the majority of OS overexpress the protooncogene HER2 raises the possibility of using HER2 as a therapeutic target. However, clinical trials on the anti-HER2 antibody trastuzumab (TRA) in treating OS find no therapeutic benefit. HER2 overexpression in OS is not generally associated with gene amplification, with low-level expression regarded as HER2 “negative”, as per criteria used to classify breast cancer HER2 status. Nevertheless, active HER2-targeting approaches, such as virus-based HER2 vaccines or CAR-T cells have generated promising results. More recently, it has been found that the noncovalent association of TRA with nanomaterial graphene oxide (GO) generates stable TRA/GO complexes capable of rapidly killing OS cells. TRA/GO induces oxidative stress and strong HER2 signaling to elicit immediate degradation of both cIAP (cellular inhibitor of apoptosis protein) and caspase 8, leading to activation of necroptosis. This is an attractive mechanism of cancer cell death as chemo/apoptosis-resistant tumors may remain susceptible to necroptosis. In addition, necroptosis is potentially immunogenic to promote tumor immunity, as opposed to apoptosis that tends to silence tumor immunity. Currently, no established anticancer therapeutics are known to eliminate cancers by necroptosis. The aim of this article is to review the rationale and mechanisms of TRA/GO-mediated cytotoxicity.

An HER2 DNA vaccine with evolution-selected amino acid substitutions reveals a fundamental principle for cancer vaccine formulation in HER2 transgenic mice.

Enhancement of endogenous immunity to tumor-associated self-antigens and neoantigens is the goal of preventive vaccination. Toward this goal, we compared the efficacy of the following HER2 DNA vaccine constructs: vaccines encoding wild-type HER2, hybrid HER2 vaccines consisting of human HER2 and rat Neu, HER2 vaccines with single residue substitutions and a novel human HER2 DNA vaccine, ph(es)E2TM. ph(es)E2TM was designed to contain five evolution-selected substitutions: M198V, Q398R, F425L, H473R and A622T that occur frequently in 12 primate HER2 sequences. These ph(es)E2TM substitutions score 0 to 1 in blocks substitutions matrix (BLOSUM), indicating minimal biochemical alterations. h(es)E2TM recombinant protein is recognized by a panel of anti-HER2 mAbs, demonstrating the preservation of HER2 protein structure. Compared to native human HER2, electrovaccination of HER2 transgenic mice with ph(es)E2TM induced a threefold increase in HER2-binding antibody (Ab) and elevated levels of IFNγ-producing T cells. ph(es)E2TM, but not pE2TM immune serum, recognized HER2 peptide p95 355LPESFDGDPASNTAP369, suggesting a broadening of epitope recognition induced by the minimally modified HER2 vaccine. ph(es)E2TM vaccination reduced tumor growth more effectively than wild-type HER2 or HER2 vaccines with more extensive modifications. The elevation of tumor immunity by ph(es)E2TM vaccination would create a favorable tumor microenvironment for neoantigen priming, further enhancing the protective immunity. The fundamental principle of exploiting evolution-selected amino acid substitutions is novel, effective and applicable to vaccine development in general.

Innate and adaptive immunotherapy: An orchestration of immunogenic cell death by overcoming immune suppression and activating NK and T-cell therapy in patients with third line or greater TNBC.

e12566 Background: Triple-negative breast cancer (TNBC) is a heterogenous subtype of breast cancer that is frequently aggressive and has limited treatment options. We hypothesize that effective and sustained response against TNBC requires a coordinated approach that: 1. reverses the immune-suppressive tumor microenvironment, 2. induces immunogenic tumor cell death and 3. reengages NK and T-cell tumor response against a 4. cascade of tumor antigens. To test this hypothesis, we have developed a temporospatial approach that combines metronomic low dose chemotherapy, SBRT, off-the-shelf cryopreserved allogeneic NK cells, yeast and adenoviral tumor-associated antigen vaccines, an IL-15RαFc superagonist, and checkpoint inhibition. Methods: A phase 1b trial in patients with previously-treated metastatic TNBC was initiated. Treatment occurred in 3-week cycles of low-dose chemotherapy (aldoxorubicin, cyclophosphamide, cisplatin, nab-paclitaxel, 5-FU/L), antiangiogenic therapy (bevacizumab), SBRT, engineered allogeneic CD16 NK-92 cells (haNK), IL-15RαFc (N-803), adenoviral vector-based CEA, MUC1, brachyury, and HER2 vaccines, yeast vector-based Ras, brachyury and CEA vaccines, and an IgG1 PD-L1 inhibitor, avelumab. The primary endpoint is incidence of treatment-related adverse events (TRAEs). Secondary endpoints include ORR, DCR, PFS, and OS. Results: 8 subjects with 3rd-line or greater TNBC have received at least 3 treatment cycles (mean = 6 cycles). All treatment was administered in an outpatient setting. All subjects had at least 1 grade ≥3 TRAE, primarily chemotherapy-related neutropenia. Grade ≥3 haNK-related AEs (fever and fatigue) were observed in 2 subjects. 2 subjects experienced SAEs. 7 subjects remain alive, with 6 subjects receiving ongoing study treatment. 1 CR (confirmed) and 2 PRs (one confirmed) have been observed to date. Conclusions: These preliminary data suggest that low-dose chemo-radiation combined with innate and adaptive immunotherapy can be administered safely in an outpatient setting with a manageable safety profile. Clinical trial information: NCT03387085.

AllergoOncology: High innate IgE levels are decisive for the survival of cancer-bearing mice

BackgroundAtopics have a lower risk for malignancies, and IgE targeted to tumors is superior to IgG in fighting cancer. Whether IgE-mediated innate or adaptive immune surveillance can confer protection against tumors remains unclear. ObjectiveWe aimed to investigate the effects of active and passive immunotherapy to the tumor-associated antigen HER-2 in three murine models differing in Epsilon-B-cell-receptor expression affecting the levels of expressed IgE. MethodsWe compared the levels of several serum specific anti-HER-2 antibodies (IgE, IgG1, IgG2a, IgG2b, IgA) and the survival rates in low-IgE ΔM1M2 mice lacking the transmembrane/cytoplasmic domain of Epsilon-B-cell-receptors expressing reduced IgE levels, high-IgE KN1 mice expressing chimeric Epsilon-Gamma1-B-cell receptors with 4-6-fold elevated serum IgE levels, and wild type (WT) BALB/c. Prior engrafting mice with D2F2/E2 mammary tumors overexpressing HER-2, mice were vaccinated with HER-2 or vehicle control PBS using the Th2-adjuvant Al(OH)3 (active immunotherapy), or treated with the murine anti-HER-2 IgG1 antibody 4D5 (passive immunotherapy). ResultsOverall, among the three strains of mice, HER-2 vaccination induced significantly higher levels of HER-2 specific IgE and IgG1 in high-IgE KN1, while low-IgE ΔM1M2 mice had higher IgG2a levels. HER-2 vaccination and passive immunotherapy prolonged the survival in tumor-grafted WT and low-IgE ΔM1M2 strains compared with treatment controls; active vaccination provided the highest benefit. Notably, untreated high-IgE KN1 mice displayed the longest survival of all strains, which could not be further extended by active or passive immunotherapy. ConclusionActive and passive immunotherapies prolong survival in wild type and low-IgE ΔM1M2 mice engrafted with mammary tumors. High-IgE KN1 mice have an innate survival benefit following tumor challenge.

A brief report of toxicity end points of HER2 vaccines for the treatment of patients with HER2+ breast cancer.

Human epidermal growth factor receptor 2 (HER2)-targeted vaccines are under development, but have so far demonstrated only modest clinical efficacy. Additionally, there has been a lack of adequate safety assessment in large-scale prospective clinical trials. Therefore, we performed a meta-analysis of available clinical trial data to summarize the toxicity profiles of these treatments. Literature search was conducted in February 2018. The trials analyzed had at least one study arm consisting of HER2 vaccine monotherapy. Heterogeneity across studies was analyzed using I2 statistics. Data were analyzed using random-effects meta-analysis for absolute risk (AR). Eight trials and 248 patients were included. There was no evidence of heterogeneity between studies for grades 3/4 adverse events (AEs) or for death. The AR for treatment-related serious AEs was 5% with no treatment-related deaths. The AR of all-grade fatigue, injection site reaction, and fever/chills/rigors was 33%, 23%, and 31%, respectively. Asymptomatic drop in left ventricle ejection fraction was rare (8%). HER2 vaccines are well tolerated with increased AR of fatigue, injection site reactions, and fever/chills/rigors.

HER2-Based Immunotherapy for Breast Cancer.

Resistance to therapies and disease recurrences after surgery or treatment are common challenges in breast cancer management in clinic. Active immunotherapy using human epidermal growth factor receptor 2 (HER2)-targeted vaccines represents an attractive option in combating breast cancer. Different HER2-derived vaccines have been developed over the years. Many clinical trials have been carried out in evaluating HER2-based vaccines. The authors reviewed current literature on HER2-based vaccines in clinical trials. The trials covered in this mini-review represent some of the major trials published in the past 20 years regarding the clinical use and test of HER2 vaccines. Their focus is on trials using HER2 peptide vaccines as the majority of clinical trials initiated or published used HER2 peptide-based vaccines. Findings from combination therapy trials of HER2 peptide vaccines with other treatment modalities are also presented.

Nitrated T helper cell epitopes enhance the immunogenicity of HER2 vaccine and induce anti-tumor immunity

Human epidermal growth factor receptor 2 (HER2) is an attractive target for cancer vaccine. However, autoimmune tolerance prevents vaccines based on HER2 protein from inducing long-lasting, highly effective anti-tumor immunity. In this study, we proved that the introduction of p-nitrophenylalanine in the universal T cell epitope (named NitraTh) enhances humoral immunity induced by B cell epitope and cellular immunity induced by CTL epitope. Moreover, this NitraTh epitope can work in both mouse and human immune system. When fused with extracellular domain 23-83 of HER2, NitraTh epitope help to break the self-tolerance of HER2 and induced strong HER2 specific humoral immunity and cellular immunity. Vaccination with HER2-NitraTh can significantly inhibit the growth of HER2+B16F10 tumor cells. These findings have important implications for developing therapeutic cancer vaccines.

Linkage between TIM3 genotype and human HER2 vaccine response in Diversity Outbred (DO) HER2 transgenic (Tg) mice

Abstract Regulatory T cell (Treg) depletion boosts HER2 vaccine response in human HER2 transgenic (Tg) mice. To test whether polymorphisms of Treg-associated genes impact vaccine response, individually distinct F1(DOxB6 HER2 Tg) mice were vaccinated 2× with Adv/HER2 to generate highly variable responses. Single nucleotide polymorphisms (SNP) of 16 candidate genes were analyzed by MonsterPlex sequencing or TaqMan assay, with TIM3 showing an association with vaccine response. There are14 SNPs in the 2kb proximal promoter region and 10 SNPs in a 1kb region containing TIM3 exon 7. Four distinct TIM3 genotypes were identified for either region with one genotype consistently matching between the promoter and exon 7 loci, i.e. the CAST/EiJ strain genotype. Analysis of 84 vaccinated DOxB6 HER2 Tg mice using a tag SNP rs28230613 showed that mice with homozygous CC produce HER2 Ab at 26.9±28.9 μg/mL, and those with heterozygous CA (CAST/Eij genotype) 12.8±19.4 μg/mL (p=0.0075). T cell response was absent in most CA heterozygotes. Relative transcript levels of splenocyte TIM3 over CD4 showed heterozygotes at 2.06±2.27 and homozygotes 0.54±0.51 (p=0.0073, n=24), indicating higher TIM3 transcript in CA heterozygotes. Thus, CAST/EiJ TIM3 genotype is associated with higher TIM3 transcript level and lower vaccine response to self HER2. This correlation is absent in mice depleted of CD25+ Treg, implicating Treg and their TIM3 in regulating HER2 vaccine response. The segregation of TIM3 genotype with vaccine response is not absolute, suggesting additional molecular regulation in HER2 vaccine response. CA76340