Autologous Dendritic Cell Vaccine Research Articles

TMIC-45. CYTOMEGALOVIRUS PP65 ANTIGEN EXPRESSION FOLLOWING PP65-SPECIFIC DENDRITIC CELL VACCINATION IN MATCHED PRIMARY AND RECURRENT GLIOBLASTOMA SPECIMENS

Abstract BACKGROUND Human cytomegalovirus (HCMV) expression in glioblastoma (GBM) has been corroborated by multiple independent laboratories. HCMV genes have been directly linked to GBM cell proliferation, invasion, and angiogenesis. The HCMV tegument protein pp65 has served as a tumor-specific antigen in serial pp65 RNA-pulsed autologous dendritic cell (DC) vaccine trials. Here we report pp65 expression in matched primary and recurrent GBM samples from those trials following pp65-DC vaccination. METHODS Paired GBM specimens were collected from patients receiving pp65-DC vaccines according to ATTAC and ATTAC-GM clinical trials (NCT00639639). Of 23 treated patients, 9 cases were available for analysis. Formalin-fixed paraffin-embedded specimens were mounted on glass slides and stained for pp65 via immunohistochemistry (IHC). CD31 served as a control for tissue quality and to investigate the role of pp65 co-staining in the tumor perivascular niche. RESULTS Of 9 available cases, 5 were excluded due to poor tissue quality/absent CD31 staining on aged slides. Among the remaining four cases, three showed pp65 staining in non-vascular and perivascular areas within both primary and recurrent samples. However, recurrent specimens of these positive cases demonstrated a clear reduction in both intensity and distribution of pp65 staining within non-vascular regions but retained a strong positivity within the perivascular space. The fourth case showed absent pp65 staining and only weakly positive CD31 staining in both primary and recurrent specimens. Necrotic areas within pp65-positive slides showed minimal to no pp65 staining. CONCLUSIONS This study confirms HCMV pp65 expression in both primary and recurrent GBM following pp65-DC vaccination, with an interesting phenomenon of retained pp65 expression specifically in the perivascular niche. These findings support the role of HCMV in GBM angiogenesis and tumor progression as well as mechanisms of immune evasion following single antigen vaccine platforms. Our study reinforces the importance of tissue quality for proper HCMV detection in GBM.

CTIM-27. DOC1021 CELL-BASED VACCINATION AS ADJUVANT THERAPY FOR GLIOBLASTOMA: PHASE I CLINICAL TRIAL ANALYSIS

Abstract Glioblastoma is an aggressive tumor for which median survival remains 14-18 months despite aggressive standard of care. Cellular immunotherapy approaches have recently shown promise. Homologous antigenic loading is an ex-vivo technique that leverages p38MAPK and mTORC1 signaling cascades to initiate powerful cDC1-like skewing in monocyte-derived dendritic cells, leading to downstream induction of tissue-infiltrating, cytolytic effector memory T-cells. This open-label phase I clinical trial evaluated the autologous dendritic cell vaccine DOC1021 prepared through homologous antigenic loading and administered bilaterally near the deep cervical lymph nodes. Three courses of vaccine were administered every 2 weeks after completion of chemoradiation, adjuvanted concurrently with six weeks of weekly type I interferon. Four dose levels from 3.5x106 to 3.6x107 total vaccine cells were tested. Tumor progression prior to vaccination was not an exclusion criterion. Sixteen newly diagnosed IDH-WT patients completed treatment, median age 63 years and 94% MGMTp unmethylated. The most common related AEs were grade 1 injection-site reactions and grade 1-3 fatigue and urticaria. No DLTs were observed. Immunohistochemistry of tumors derived from early post-vaccination second resections showed enhanced CD8+ T-cell infiltration and pathologic findings consistent with residual rather than relapsed GBM in 2/3 patients. Analysis of post-vaccination PBMC in dose level cohorts 2-4 indicated expansion of both CD4+ (13/13) and CD8+ (11/13) central memory T-cell compartments (p<0.002 and p<0.05, respectively) as well as expansion of CD8+CD127+ T-cells (12/13; p<0.001). Among three patients for whom tissue was obtained pre- and post-vaccination, clinical outcomes correlated with Visium spatial transcriptomic analysis. Median survival for the MGMTp unmethylated cohort (n=15) has not yet been reached but is statistically greater (p<0.05) than that of matched historic controls. The results indicate that DOC1021 is safe, can be effectively integrated within existing standards of care and is potentially efficacious in a challenging patient population.

The clinical utility of autologous tumor lysate-loaded dendritic cell vaccination for patients with glioma: A systematic review and meta-analysis.

Dendritic cell (DC) vaccines show promise for glioma treatment, but optimal use remains uncertain. This meta-analysis examined DC vaccine efficacy and safety for gliomas. This systematic review and meta-analysis study was conducted using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. From the date of inception to October 23, 2023, electronic databases PubMed, Embase, Web of Science, and Scopus have been thoroughly evaluated. A total of 12 studies with 998 patients and a mean age ranging from 40.2 to 56 years were included. Across 12 articles, DC vaccine 6-month overall survival (OS) was 100% [95% confidence interval {95%CI}: 100%-100%]. Respectively, 12-month OS reported 75% [95%CI: 65%-85%] but declined to 32% [95%CI: 20%-43%] for 24-month OS. 6- and 12-month progression-free survival reached 49% [95%CI: 21%-77%] and 19% [95%CI:8%-30%]. Studying radiological outcomes shows that complete response and partial response rates were 13% [95%CI: 17%-42%], and 26% [95%CI: 10%-42%], though stable disease reached 33% [95%CI: 15%-51%], suggesting predominant antineoplastic effects. The progressive disease rate also was 24% [95%CI: 9%-57%]. In gliomas, DC vaccinations show a temporary efficacy; stability is more prevalent than regression. Impacts favor decreased resistance to early disease. Enhancing efficacy remains critical. Early therapy can be enhanced by appropriate supplementary therapy integration.

Tumor regression following autologous tumor lysate-loaded dendritic cell vaccination immunotherapy: illustrative case.

Despite years of research, the standard of care (SOC) treatment for grade 4 glioma has remained virtually unchanged for the last 2 decades. Autologous tumor lysate-loaded dendritic cell vaccination (DCVax-L), a novel immunotherapy, has demonstrated a significant survival benefit in a phase 3 trial. A 34-year-old male presented with episodes of lightheadedness and was subsequently diagnosed with a large fronto-insulo-temporal tumor, likely to be high grade. He underwent an asleep craniotomy for debulking, with a residual tumor noted in the frontal lobe and amygdala. Tumor histopathology was reported as isocitrate dehydrogenase (IDH) mutant methylated grade 4 astrocytoma. He received SOC treatment, alongside a course of DCVax-L. Surveillance imaging showed cystic transformation followed by a reduction in size of the residual tumor in the frontal lobe; the residual in the amygdala had regressed entirely. The patient remained clinically well and had returned to his preoperative functionality. The authors report a patient with grade 4 astrocytoma who received DCVax-L treatment in addition to SOC adjuvant therapy. The pattern and extent of tumor regression are highly unusual and atypical for what is seen or expected with adjuvant SOC treatment alone. The addition of DCVax-L to SOC opens new avenues in the management of this difficult disease. https://thejns.org/doi/10.3171/CASE24112.

Personalized neoantigen-pulsed autologous dendritic cells vaccine as an adjuvant treatment for patients with newly-diagnosed glioblastoma multiforme: A phase I trial.

e14025 Background: Glioblastoma Multiforme (GBM) is the most common and aggressive primary brain malignancy in adults. We herein report a phase I trial using personalized neoantigen-pulsed autologous dendritic cells (nDC) vaccine as an adjuvant treatment for patients with newly-diagnosed GBM. Methods: It is a single-center, single-arm phase I trial, enrolling patients aged 18-75 years old, with newly-diagnosed GBM and tumor resection extent ≥90%. Tumor specimens were sequenced for identification of personalized neoantigens. A total of 3-10 neoantigen peptides were loaded into DC to generate the nDC vaccine. The vaccine was administered subcutaneously for 5-6 doses at 1×10^7 cells following concomitant radiotherapy plus temozolomide. The primary objective is safety. Secondary objectives include survival outcomes and T cell immune response against the neoantigens. Results: As of Dec. 31, 2023, eleven patients completed at least one dose of vaccination and were included in the safety analysis; eight patients completed planned doses and were included in the efficacy analysis. All the patients reported Treatment-emergent adverse events (TEAEs). Most TEAEs were grade 1 or 2. One patient reported two grade 3 TEAEs: decreased white blood cell count and decreased lymphocyte count. Pyrexia was considered as treatment-related adverse event (TRAE) that was reported in two (18.2%) patients. No treatment-related deaths occurred. Among eight efficacy-assessable patients, seven (87.5%) patients kept progression-free for at least 5.4-27.3 months; one patient progressed at 10.2 months after surgery and achieved complete remission after receiving anti-PD1 plus bevacizumab therapy; compared to the baseline level, a median 15-fold (3 to 506-fold) increase of neoantigen-specific cytotoxic T cells was detected in their peripheral blood samples post-vaccination, indicating strong anti-tumor T cell responses elicited by the nDC vaccine. Conclusions: The nDC vaccine, combined with the standard treatments for GBM, was well tolerated. Initial results from this ongoing study have exhibited encouraging survival outcome of the nDC vaccine for patients with newly-diagnosed GBMs. Clinical trial information: NCT04968366 . [Table: see text]

A pilot trial of personalized neoantigen pulsed autologous dendritic cell vaccine as adjuvant treatment in hepatocellular carcinoma.

e16264 Background: The primary treatment for hepatocellular carcinoma (HCC) is radical surgery. However, HCC has a high propensity to recur postoperatively and no standard adjuvant therapies have been approved. This Phase I trial aims to evaluate the safety and efficacy of an adjuvant personalized neoantigen pulsed autologous dendritic cell vaccine (Neo-DCVac-02) in patients with HCC. Methods: Eligible patients had histologically confirmed high-risk HCC after radical surgery. After obtaining the necessary baseline biopsy specimens and PBMCs of appropriate quality for DNA and RNA sequencing, neoantigen prediction, screening and synthesis were performed. Subsequently, leukapheresis was performed and DCs were isolated and cultured. DCs were then pulsed with neoantigen peptides to produce Neo-DCVac-02. On day 0, patients were treated with cyclophosphamide at a dose of 250 mg/m2. The prepared Neo-DCVac-02 vaccine was administered subcutaneously to the axillary and inguinal regions bilaterally on day 1, followed by daily administration of GM-CSF at a dose of 0.075 mg for 5 days (days 2-6). The primary objectives of this study were to assess feasibility and safety/tolerability. Secondary objectives included evaluation of immune responses (via vaccine response: IFNγ ELISpot), relapse-free survival (RFS) and overall survival (OS). Results: A total of 32 patients provided informed consent to initiate the process of personalized neoantigen discovery, of which 26 (81%) met the requirements for successful product selection for clinical manufacturing. Feasibility was demonstrated with 13 patients receiving Neo-DCVac-02. 13 patients did not receive the neoantigen vaccine (7 due to progressive disease, 6 due to withdrawal of informed consent because of COVID-19). The treatment was well tolerated with no grade 2+ treatment-related adverse events (TRAEs). The most common Grade 1 TRAEs were injection site reactions (75%), rash (16.7%), fatigue (8.3%), neutropenia (8.3%), and headache (8.3%). Five of 13 evaluable patients showed increased antigen-specific T-cell activity and more than 50% of the neoantigen peptides in Neo-DCVac-02, and sustained cellular responses were observed up to one year. Increases in T-cell activation/co-stimulation seen after treatment with Neo-DCVac-02, as demonstrated by flow cytometric analysis, suggest immune priming. At a median follow-up of 29.7 months, median RFS was not reached, with 1- and 2-year RFS of 84.6% and 60%, respectively, and all patients are alive. Patients with a strong immune response had a longer median relapse-free survival (not reached) compared to patients with a weak immune response (17.6 months, P = 0.003). Conclusions: These data demonstrate that Neo-DCVac-02 is safe, well tolerated and capable of inducing durable antigen-specific lymphocyte immune responses that may correlate with delayed HCC recurrence. Clinical trial information: NCT04147078 .

TLR agonists polarize interferon responses in conjunction with dendritic cell vaccination in malignant glioma: a randomized phase II Trial

In this randomized phase II clinical trial, we evaluated the effectiveness of adding the TLR agonists, poly-ICLC or resiquimod, to autologous tumor lysate-pulsed dendritic cell (ATL-DC) vaccination in patients with newly-diagnosed or recurrent WHO Grade III-IV malignant gliomas. The primary endpoints were to assess the most effective combination of vaccine and adjuvant in order to enhance the immune potency, along with safety. The combination of ATL-DC vaccination and TLR agonist was safe and found to enhance systemic immune responses, as indicated by increased interferon gene expression and changes in immune cell activation. Specifically, PD-1 expression increases on CD4+ T-cells, while CD38 and CD39 expression are reduced on CD8+ T cells, alongside an increase in monocytes. Poly-ICLC treatment amplifies the induction of interferon-induced genes in monocytes and T lymphocytes. Patients that exhibit higher interferon response gene expression demonstrate prolonged survival and delayed disease progression. These findings suggest that combining ATL-DC with poly-ICLC can induce a polarized interferon response in circulating monocytes and CD8+ T cells, which may represent an important blood biomarker for immunotherapy in this patient population.Trial Registration: ClinicalTrials.gov Identifier: NCT01204684.

Development of a Protocol for Obtaining a Homologous Cell Product of Animal Origin Intended for Preclinical Studies of Antitumor Vaccine CaTeVac.

When developing a program of preclinical studies of human cell-based drugs intended for adoptive immunotherapy of cancer patients, the biological effect should be substantiated by data describing their immunological action. Administration and study of human autologous dendritic cell vaccine to immunocompetent animals are not adequate in terms of immunological compatibility. It is possible to use immunocompromised, knockout, or transgenic animals or to obtain a homologous cellular product, namely, a preparation based on animal cells using a technology similar to obtaining the original preparation for clinical practice in humans. Within the framework of this study, we have developed a protocol for obtaining a homologous cell product based on animal dendritic cells (mice, rats) according to a similar technology for obtaining human vaccine dendritic cells, and demonstrated the comparability of morphological characteristics and expression of differentiation antigens of dendritic cells (CD11c, CD80, CD86, and CD83) of animals (mice) and humans.

Immunophenotype of dendritic cell differentiation markers in breast cancer in in-vitro conditions

BACKGROUND: During maturation, dendritic cells begin to synthesize peptides that include the major histocompatibility complex MHC-II molecules, costimulatory molecules CD40+, CD80+, and CD86+, as well as CD83+ proteins. In cancer patients, dendritic cells dysfunction can lead to serious consequences in the form of deficiency of antitumor immunity, tumor progression, and decreased response to immunotherapy. All this is important to take into account to rethink the tumor immunotherapy strategy. Thus, approaches aimed at enhancing the viability of dendritic cells and preventing their dysfunction and polarization should be considered as a necessary step in order to increase the effectiveness of dendritic cell vaccines.
 AIM: To evaluate the expression characteristics of differentiation markers of dendritic cell maturation obtained from peripheral blood monocytes under culture conditions in patients with breast cancer.
 MATERIALS AND METHODS: With informed voluntary consent, 19 patients diagnosed with breast cancer were examined. Mononuclear cells were isolated on a Ficoll density gradient. For adhesion of monocytes to the bottom of 75 cm2 culture flasks, they were pre-incubated for 1.5 hours in conditions of 5% CO2 at 37 ℃. Growth and differentiation factors — GM-CSF (40 µl) and IL-٤ (٤٠ µl) — were added to the attached monocytes on the 1st, 3rd and 5th days of cultivation. Immunophenotyping of dendritic cells was carried out on days 7 and 9 of cultivation using flow cytometry.
 RESULTS: Flow cytometry data indicate that the viability of cultured dendritic cells in cancer patients is significantly reduced on day 9 compared to day 7 of cultivation. On day 9, there was a significant increase in CD80+ expression (2.40, p=0.028) and a decrease in CD83+ (1.65, p=0.036) compared to day 7.
 CONCLUSION: In general, significant signs of maturation were observed: loss of the monocyte marker CD14+, increased expression of CD80+, CD83+, CD86+ — the main markers. A decrease in CD83+ can be considered as a suppression of excessive activation of immune responses. In the future, a more in-depth study of the characteristics of maturation and activation of cultured dendritic cells is necessary to understand the mechanisms and factors influencing the decrease in the effectiveness of immunotherapy with an autologous dendritic cell vaccine.

IMMU-13. DEVELOPMENT OF ADAPTIVE IMMUNE RESISTANCE IN A MURINE GLIOMA MODEL TREATED WITH DENDRITIC CELL VACCINATION AND PD-1 CHECKPOINT BLOCKADE

Abstract Immunotherapies such as immune checkpoint inhibitors and active vaccination have shown great potential in unleashing antitumor immunity for cancer treatment. However, their effectiveness in treating glioblastoma (GBM) is limited. In a preclinical glioma model, administration of both autologous tumor lysate-pulsed dendritic cell vaccination (ATL-DC) and anti-PD-1 checkpoint blockade (aPD1) significantly increased survival and enhanced intratumoral T cell activation. We hypothesize that the combination of these two treatments will substantially increase the abundance and activity of tumor-reactive cytotoxic T cells. As such, we recently started a phase I trial administering ATL-DC and neoadjuvant aPD1 to recurrent GBM patients (NCT ID: NCT04201873). To understand the local antitumor immune response in greater depth, we performed single-cell RNA sequencing analysis of the CD45+ immune compartment of explanted gliomas from twelve mice, four of which were treated with ATL-DC and aPD1 while the other eight received no treatment. We found that the combination therapy increased tumor-infiltrating T cells, monocytes and DCs. We also observed the expansion and differentiation of CD8+ effector T cells under the effect of combination therapy. These T cells exhibited a differentiation trajectory from a Tcf7+Il2ra+ early activated phenotype to a terminally exhausted state marked by high expression of Pdcd1, Tox and Tigit. Interestingly, combination therapy specifically increased a macrophage subset that overexpressed Ch25h, an interferon-stimulated gene encoding for the oxysterol lipid 25-hydroxycholesterol (25-HC). Preliminary results from in vitro studies demonstrated that 25-HC restricted T cell proliferation and tumor cell cytolysis, suggesting its immunosuppressive function. In summary, our study reveals the impact of ATL-DC + aPD1 combination therapy on the immune microenvironment of GBM and a potential maladaptive mechanism mediated by 25-HC. Future studies will seek to exploit these targets therapeutically to develop more effective GBM treatment regimens.

Ksd-101 in Patients with EBV-Associated Hematologic Neoplasms: Results from an Ongoing Phase I Clinical Study

Background: The Epstein-Barr Virus (EBV), which has been confirmed by WHO as the first human tumor-associated virus, is a lifelong carrier once infected. EBV-associated Hematologic Neoplasms seriously threats human health, with rapid disease progression, poor prognosis, easy to relapse, and high mortality rate. KSD-101 is a First-in-class autologous dendritic cell (DC) vaccine which is developed to control EBV-associated hematological diseases. Autologous DCs were loaded with the EBV-transformed B-LCL (B-Lymphoblastoid Cell Line) lysates which contains a broad-spectrum EBV antigen to prepare KSD-101 for the treatment of EBV-associated diseases. Methods: In this study, patients (pts) with EBV-associated Hematologic Neoplasms who fail to respond to or relapse after conventional treatment will be recruited and undergo leukapheresis to collect autologous peripheral blood mononuclear cell (PBMC). The enriched monocytes will be induced to differentiate into DCs and prepared as KSD-101 after loading with EBV-transformed B-LCL. Pts will undergo monotherapy with KSD-101, without the need for pre-treatment of lymphodepletion or prophylactic medication. Administration route of KSD-101 is subcutaneous injection, once every 2 weeks for 3-5 vaccinations in total. The study used a 3+3 dose-escalation design. Safety assessment is conducted according to NCI-CTCAE 5.0 grading criteria. The primary objective is to assess the tolerability and safety of KSD-101 in the treatment of EBV-associated Hematologic Neoplasms, explore the dose-limiting toxicities (DLT) and the maximum tolerated dose (MTD). The secondary objective is to explore the clinical efficacy and immune responses of KSD-101 in the patients with EBV-associated Hematologic Neoplasms. Results: As of July 2023, 9pts were enrolled in the study and 8 pts DC vaccine preparations were completed. Three pts were injected 5.0 × 10 6 cells/dose without exploring any DLT. The first two pts in the second dose level were injected 7.5 × 10 6 cells/dose. However, the third pt in second dose level was injected 5.0 × 10 6 cells/dose due to insufficient apheresis collection. Based on the safety and preliminary efficacy data, we decided not to proceed with dose-escalation to the third dose group. In the expansion phase, all pts were injected with a dose of 5.0 × 10 6 cells. Currently observed KSD-101-related toxicities were pyrexia (grade ≤ 2), injection site reactions (grade 1), and lymphadenopathy (grade 1). In all the pts who were injected, neither DLT nor MTD were explored. Based on the comprehensive considerations of safety, efficacy and easibility, we propose that the most appropriate dose is 5.0 × 10 6 cells. Of all pts enrolled, one was excluded due to hemophagocytic lymphohistiocytosis (HLH), among whom 4 pts completed the 12-week follow-up after the first injection for clinical and laboratory assessments. The results showed an overall response rate (ORR):100%, complete response (CR):100%, including 1 case of AITL (EBV infected T, B, NK),1case of CAEBV (EBV infected T, NK),2cases of NK-T cell lymphoma (1 EBV infected B, NK, and the other EBV infected NK). After vaccinations, the total number of lymphocytes of these four pts increased by 1.5 to3.4 times, including 1.6 to 4.2 times of T cells, 2.1 to 6.5 times of activated T cells (CD3 + HLA -DR +), 1.4 to 5.0 times of CD8 + T cells, 1.2 to 3.7 times of CD4 + T cells, 1.7 to 2.0 times of NK cells, and 1.2 to 32.4 times of B cells; meanwhile, the proportion of EBV-specific CTLs increased significantly (ranging from a 2.51% to 4.16% increase), and the proportion of Tregs significantly decreased compared with the baseline (ranging from a 32.49% to 73.81% reduction). Conclusions：Our current study shows that KSD-101 has excellent safety and good preliminary efficacy against EBV-associated Hematologic Neoplasms with efficient induction of immune responses. The results indicate that KSD-101 is a promising therapeutic reagent for the treatment of EBV-associated Hematologic Neoplasms. Larger prospective studies and longer follow-up time is needed to be conducted.

WT1 and PRAME RNA-loaded dendritic cell vaccine as maintenance therapy in de novo AML after intensive induction chemotherapy.

Intensive induction chemotherapy achieves complete remissions (CR) in >60% of patients with acute myeloid leukemia (AML) but overall survival (OS) is poor for relapsing patients not eligible for allogeneic hematopoietic stem cell transplantation (allo-HSCT). Oral azacytidine may be used as maintenance treatment in AML in first remission, but can be associated with substantial side effects, and less toxic strategies should be explored. Twenty AML patients in first CR (CR1) ineligible for allo-HSCT were treated with FDC101, an autologous RNA-loaded mature dendritic cell (mDC) vaccine expressing two leukemia-associated antigens (LAAs). Each dose consisted of 2.5-5 × 106 mDCs per antigen, given weekly until week 4, at week 6, and then monthly, during the 2-year study period. Patients were followed for safety and long-term survival. Treatment was well tolerated, with mild and transient injection site reactions. Eleven of 20 patients (55%) remained in CR, while 4 of 6 relapsing patients achieved CR2 after salvage therapy and underwent allo-HSCT. OS at five years was 75% (95% CI: 50-89), with 70% of patients ≥60 years of age being long-term survivors. Maintenance therapy with this DC vaccine was well tolerated in AML patients in CR1 and was accompanied by encouraging 5-year long-term survival.

DCVax-L Vaccination in Patients with Glioblastoma: Real Promise or Negative Trial? The Debate Is Open.

The lack of significant improvement in the prognosis of patients with GB over the last decades highlights the need for innovative treatments aimed at fighting this malignancy and increasing survival outcomes. The results of the phase III clinical trial of DCVax-L (autologous tumor lysate-loaded dendritic cell vaccination), which has been shown to increase both median survival and long-term survival in newly diagnosed and relapsed glioblastoma, have been enthusiastically received by the scientific community. However, this study deserves some reflections regarding methodological issues related to the primary endpoint change, the long accrual period, and the suboptimal validity of the external control population used as the comparison arm.

A pilot trial of personalized neoantigen pulsed autologous dendritic cell vaccine as adjuvant treatment in hepatocellular carcinoma.

e14658 Background: The primary means of treating hepatocellular carcinoma (HCC) is radical surgery. However, HCC has a high propensity to recur post-operatively, and no standard adjuvant therapies have been approved. Tumor neoantigens, which are epitopes derived from tumor-specific mutations, may be utilized in personalized vaccines to activate T cell responses. This trial aims to assess the safety and efficacy of personalized neoantigen pulsed autologous dendritic cell vaccine (Neo-DCVac-02) in patients with HCC. Methods: Eligible patients had histologically confirmed high-risk HCC after radical surgery. Upon obtaining the baseline biopsy specimens and PBMCs of appropriate quality for DNA and RNA sequencing, neoantigen prediction, screening, and synthesis were performed. Subsequently, autologous dendritic cells (DCs) were generated and pulsed with neoantigen peptides to produce Neo-DCVac-02.On day 0, patients were treated with cyclophosphamide at a dose of 250 mg/m2. The prepared Neo-DCVac-02 vaccine was administered subcutaneously on day 1, followed by GM-CSF administered daily for 5 days. The primary objectives of this study were to evaluate the feasibility and safety/tolerability. Secondary objectives included assessment of immune responses (via vaccine response: IFNγ ELISpot), recurrence-free survival (RFS), and overall survival (OS). Results: A total of 32 patients provided informed consent to initiate the process of personalized neoantigen discovery, of which 26 (81%) met the requirements for successful product selection for clinical manufacturing. And feasibility was shown with 13 patients receiving Neo-DCVac-02. Thirteen patients did not receive neoantigen vaccines (7 for progressive disease,6 for withdrawal of informed consent because of COVID-19). Treatment was well-tolerated with no grade 2+ treatment-related adverse events (TRAEs). The common grade 1TRAEs were neutropenia (8.3%), injection site reactions (75%), rash (16.7%), fatigue (8.3%), and headache (8.3%). The median follow-up to date is 19.30 (14.4-31.9) months, with median RFS and OS not yet reached and a 1-year RFS of 83%. Five of 13 evaluable patients showed elevated antigen-specific T-cell activity by IFNγ ELISpot for more than 50% of neoantigen peptides in Neo-DCVac-02, and persistent cellular responses were noted out to 1 year. Increases in activation/co-stimulatory of T cells seen after treatment with Neo-DCVac-02 revealed by Flow-cytometric analyses, suggest immune priming. Conclusions: These data demonstrate that Neo-DCVac-02 is safe, well tolerated, and able to generate durable antigen-specific lymphocyte immune responses. Early signs of clinical efficacy were observed in HCC patients. Clinical trial information: NCT04147078 .

Efficacy of a Dual-Epitope Dendritic Cell Vaccine as Part of Combined Immunotherapy for HER2-Expressing Breast Tumors.

Previous work from our group and others has shown that patients with breast cancer can generate a T cell response against specific human epidermal growth factor 2 (HER2) epitopes. In addition, preclinical work has shown that this T cell response can be augmented by Ag-directed mAb therapy. This study evaluated the activity and safety of a combination of dendritic cell (DC) vaccination given with mAb and cytotoxic therapy. We performed a phase I/II study using autologous DCs pulsed with two different HER2 peptides given with trastuzumab and vinorelbine to a study cohort of patients with HER2-overexpressing and a second with HER2 nonoverexpressing metastatic breast cancer. Seventeen patients with HER2-overexpressing and seven with nonoverexpressing disease were treated. Treatment was well tolerated, with one patient removed from therapy because of toxicity and no deaths. Forty-six percent of patients had stable disease after therapy, with 4% achieving a partial response and no complete responses. Immune responses were generated in the majority of patients but did not correlate with clinical response. However, in one patient, who has survived >14 y since treatment in the trial, a robust immune response was demonstrated, with 25% of her T cells specific to one of the peptides in the vaccine at the peak of her response. These data suggest that autologous DC vaccination when given with anti-HER2-directed mAb therapy and vinorelbine is safe and can induce immune responses, including significant T cell clonal expansion, in a subset of patients.

Peptide-pulsed MHC class II mutant dendritic cell vaccine has superior efficacy in a murine tumor model.

Abstract Autologous dendritic cell (DC) vaccines with tumor antigens have been used clinically with limited therapeutic effects. Semi-allogeneic DC-based immunotherapy is still controversial, but it can be an alternative source and more attractive than autologous DC vaccines because the “off-the-shelf” DCs can be used for multiple patients without lengthy individual manufacturing time and may provide additional “allogeneic help”. This study aims to compare efficacy of syngeneic DC vaccines and semi-allogeneic DC vaccines and determine whether a therapeutic semi-allogeneic DC vaccine is more efficacious in tumor suppression. Female C57BL/6 mice were inoculated subcutaneously with human papillomavirus E6 and E7-expressing TC-1 cells. Syngeneic bone marrow dendritic cells (BMDCs) were generated from C57BL/6 and semi-allogeneic BMDCs were generated from two mouse strains, B6.C-H2-K bm1/ByJ and B6(C)-H2-Ab1 bm12/KhEgJ which had limited point mutations in the MHC class I H2-K ballele or H2-lA bMHC class II allele, respectively. Each BMDC was pulsed with H-2D b-restricted E7 43–77peptide and matured before injection. The mice received 4 intradermal injections of syngeneic or one of the semi-allogeneic E7-pulsed BMDC vaccines starting 8–9 days after the TC-1 implantation. Compared with saline control, the MHC class I mutant BMDC vaccine had efficacy similar to the syngeneic BMDC vaccine in suppressing TC-1 tumor growth. However, the MHC class II mutant BMDC vaccine had efficacy significantly superior to that of the other BMDC vaccines. Thus, MHC class II semi-allogeneic BMDCs may be more effective than syngeneic DC-based cancer vaccines, presumably because the class II alloantigens induce additional T cell help for anti-tumor immunity.

Assessment of treatment response to dendritic cell vaccine in patients with glioblastoma using a multiparametric MRI-based prediction model.

Autologous tumor lysate-loaded dendritic cell vaccine (DCVax-L) is a promising treatment modality for glioblastomas. The purpose of this study was to investigate the potential utility of multiparametric MRI-based prediction model in evaluating treatment response in glioblastoma patients treated with DCVax-L. Seventeen glioblastoma patients treated with standard-of-care therapy + DCVax-L were included. When tumor progression (TP) was suspected and repeat surgery was being contemplated, we sought to ascertain the number of cases correctly classified as TP + mixed response or pseudoprogression (PsP) from multiparametric MRI-based prediction model using histopathology/mRANO criteria as ground truth. Multiparametric MRI model consisted of predictive probabilities (PP) of tumor progression computed from diffusion and perfusion MRI-derived parameters. A comparison of overall survival (OS) was performed between patients treated with standard-of-care therapy + DCVax-L and standard-of-care therapy alone (external controls). Additionally, Kaplan-Meier analyses were performed to compare OS between two groups of patients using PsP, Ki-67, and MGMTpromoter methylation status as stratification variables. Multiparametric MRI model correctly predicted TP + mixed response in 72.7% of cases (8/11) and PsP in 83.3% (5/6) with an overall concordance rate of 76.5% with final diagnosis as determined by histopathology/mRANO criteria. There was a significant concordant correlation coefficient between PP values and histopathology/mRANO criteria (r = 0.54; p = 0.026). DCVax-L-treated patients had significantly prolonged OS than those treated with standard-of-care therapy (22.38 ± 12.8 vs. 13.8 ± 9.5months, p = 0.040). Additionally, glioblastomas with PsP, MGMT promoter methylation status, and Ki-67 values below median had longer OS than their counterparts. Multiparametric MRI-based prediction model can assess treatment response to DCVax-L in patients with glioblastoma.

Autologous dendritic cell vaccination against HIV-1 induces changes in natural killer cell phenotype and functionality

Although natural killer (NK) cells have been studied in connection with dendritic cell (DC)-based vaccination in the field of cancer immunology, their role has barely been addressed in the context of therapeutic vaccination against HIV-1. In this study, we evaluated whether a therapeutic DC-based vaccine consisting of monocyte-derived DCs electroporated with Tat, Rev and Nef encoding mRNA affects NK cell frequency, phenotype and functionality in HIV-1-infected individuals. Although the frequency of total NK cells did not change, we observed a significant increase in cytotoxic NK cells following immunisation. In addition, significant changes in the NK cell phenotype associated with migration and exhaustion were observed together with increased NK cell-mediated killing and (poly)functionality. Our results show that DC-based vaccination has profound effects on NK cells, which highlights the importance of evaluating NK cells in future clinical trials looking at DC-based immunotherapy in the context of HIV-1 infection.

Development of in vitro laboratory models of the tumor immune microenvironment to evaluate quality parameters and specific efficacy of the dendritic cell vaccine

Purpose of the study: development of in vitro laboratory models to evaluate quality parameters and specific efficacy of dendritic cell vaccine (DCV).Material and Methods. Biological samples of malignant tumor patients treated with autologous dendritic cell vaccine (DC) were included into the study. Immature DCs (n=46) and mature DCs (n=56) were used to induce proliferation of antigen-specific T lymphocytes (n=227). Autologous tumor cells from skin melanoma (n=10) or sarcoma (n=8) patients in the xCELLigence® assay system were used to study the in vitro antitumor cytotoxic activity of generated CTLs (n=18). The secretion of cytokines and cytolytic proteins was studied by multiplex analysis. The subpopulation composition of effector T-lymphocytes was determined by flow cytometry.Results. We revealed that mature DCs (CD83+CD1a-) had a high expression of antigen presenting molecules (HLA-DR) and those providing migration of DCs into lymph nodes (CCR7) as well as costimulatory molecules CD80 and CD86 as compared to immature DCs (CD83-CD1a+). Induction of mature DCs was found to stimulate an increase in the relative content of proliferating T cells compared with stimulation of immature DCs (p<0.001) and specific PTA+ tumor lysate (p<0.001). When studying cytotoxic activity of effector T-lymphocytes, we developed 2D in vitro models using xCELLigence® analytical system and revealed 2 types of interaction: 1) in vitro model № 1 – decrease in cell index (CI) of autologous tumor cell culture in the presence of activated effector T lymphocytes; 2) in vitro model № 2 – no change in CI of autologous tumor cell culture when co-cultured with activated effector T cells compared to control (72 h observation). The results demonstrated cytotoxic activity of antigen-specific T lymphocytes due to high content of terminally differentiated cytotoxic T lymphocytes (TEMRA), GrB-producing CTLs, and cytokine secretion profile.Conclusion. Requirements for the quality of personalized autologous DCs, including control of immunophenotypic characteristics were developed, and functional activity of Tlymphocytes during induction of mature vaccine DCs was evaluated. A laboratory procedure was developed for quantitative assessment of cytotoxic activity of antigen-specific T-lymphocytes against autologous tumor using the xCELLigence® analytical system, thus allowing for personalized monitoring and predicting the effectiveness of DСV treatment.

Glioblastoma treatment slowly moves toward change: novel druggable targets and translational horizons in 2022

ABSTRACT Introduction Glioblastoma (GBM) is the most common primary brain tumor in adults. GBM treatment options have been the same for the past 30 years and have only modestly extended survival, despite aggressive multimodal treatments. The progressively better knowledge of GBM biology and a comprehensive analysis of its genomic profile have elucidated GBM heterogeneity, contributing to a more effective molecular classification and to the development of innovative targeted therapeutic approaches. Areas covered This article reports all the noteworthy innovations for immunotherapy and targeted therapy, providing insights into the current advances in trial designs, including combination therapies with immuno-oncology agents and target combinations. Expert opinion GBM molecular heterogeneity and brain anatomical characteristics critically restrain drug effectiveness. Nevertheless, stimulating insights for future research and drug development come from innovative treatment strategies for GBM, such as multi-specific ‘off-the-shelf’ CAR-T therapy, oncolytic viral therapy and autologous dendritic cell vaccination. Disappointing results from targeted therapies-clinical trials are mainly due to complex interferences between signaling pathways and biological processes leading to drug resistance: hence, it is imperative in the future to develop combinatorial approaches and multimodal therapies.