Dendritic Cell Vaccine Research Articles

A tumor–immune interaction model with the effect of impulse therapy

A mathematical model describing the growth of tumor cells and the effect of impulsive therapy is studied in this paper. The governing equations and parameters related to the proposed model are based on the experimental and clinical outcome. Employing the quasi-steady-state approximation in delineating the dynamics of tumor–immune under different cytokines, a four-dimensional deterministic system is obtained. We explore the steady states, local and global stability criteria, transcritical bifurcation and boundary separation for the given model. The tumor cells are characterized by their growth rate and the tumor control region is determined in the parametric space. An impulsive differential equation is considered to determine the interval for perfect dosing of dendritic cell vaccination to boost the immune response. The effect of dendritic cell vaccination is determined by taking into account both perfect and imperfect therapeutics and the optimal number for therapeutics is computed. Our model demonstrates that the dendritic cell vaccination boosts the immune system and eradicates the tumor cell population.

Revolutionizing cancer treatment by boosting dendritic cell vaccine efficacy with graphene oxide

Dendritic cells (DCs) are potent antigen presenting cells that play a crucial role in stimulating T cell responses against cancer. DC vaccines have been utilized as an immunotherapy approach for cancer treatment, but their effectiveness is hampered by challenges in the tumor microenvironment. Graphene oxide (GO), a cutting-edge carbon-based nanomaterial, has shown promise in modulating DC activation and function. This review highlights the recent advancements in DC vaccines and explores how GO can enhance their efficacy for cancer treatment. By leveraging the unique properties of GO, such as its biocompatibility and immunomodulatory effects, DC vaccines can potentially be optimized to overcome the limitations of the tumor microenvironment and achieve improved outcomes in cancer immunotherapy.

COMPARITIVE STUDY OF DENDRITIC CELL VACCINE PREPARATION WITH PRESENCE AND ABSENCE OF MALPIGHIA EMARGINATA FRUIT EXTRACT USING TUMOR RNA TRANSFECTION METHOD: A PROMISING APPROACH FOR PROSTATE CANCER

Acerola (Malpighia emarginata DC) is the richest natural source of ascorbic acid and also contains a plethora of phytonutrients such as flavonoids, anthocyanins, carotenoids, and phenolics. By using the fruits of Malpighia emarginata, are used for the treatment of cancer by inducing effective anti-tumor immunity through dendritic cells. Dendritic cells (DC) are the heterogeneous population of antigen-presenting cells that invade tumors. They play an important role in the priming and maintenance of local immunity, and their major function is diminished by some factors encountered in the local environment. For the success of cancer immunotherapy, adequate tumor-specific antigens play a very important role in inducing a tumor-specific immune response by effective delivery of these antigens. In this proposal, by using these strategies, mature and immature dendritic cells were obtained in-vitro by adding specific cytokines to monocyte cell culture containing Malpighia emarginata fruit extract in the presence of prostate-specific antigen (PSA), and their results were compared to those obtained without the presence of Malpighia emarginata fruit extract. In the prostate tumor lineage, the RNA is extracted into the cell by electroporation, and the transfection success was measured by immunocytochemistry of the PSA expression level in dendritic cells. For the comparative study of in-vitro RNA transcription, this method allows small tumors to be used for dendritic cell vaccine preparation through the activation of DC by in the presence and absence of Malpighia emarginata fruit extract and it is a promising approach for the treatment of metastatic prostate cancer.

Efficacy and safety of innate and adaptive immunotherapy combined with standard of care in high-grade gliomas: a systematic review and meta-analysis.

Malignant glioma is the most common intracranial malignant tumor with the highest mortality. In the era of immunotherapy, it is important to determine what type of immunotherapy provides the best chance of survival. Here, the efficacy and safety of immunotherapy in high-grade glioma (HGG) were evaluated by systematic review and meta-analysis. The differences between various types of immunotherapy were explored. Retrieved hits were screened for inclusion in 2,317 articles. We extracted the overall survival (OS) and progression-free survival (PFS) hazard ratios (HRs) as two key outcomes for examining the efficacy of immunotherapy. We also analyzed data on the reported corresponding adverse events to assess the safety of immunotherapy. This study was registered with PROSPERO (CRD42019112356). We included a total of 1,271 patients, of which 524 received a combination of immunotherapy and standard of care (SOC), while 747 received SOC alone. We found that immunotherapy extended the OS (HR = 0.74; 95% confidence interval [CI], 0.56-0.99; Z = -2.00, P = 0.0458 < 0.05) and PFS (HR = 0.67; 95% CI, 0.45-0.99; Z = -1.99, P = 0.0466 < 0.05), although certain adverse events occurred (proportion = 0.0773, 95% CI, 0.0589-0.1014). Our data have demonstrated the efficacy of the dendritic cell (DC) vaccine in prolonging the OS (HR = 0.38; 95% CI, 0.21-0.68; Z = -3.23; P = 0.0012 < 0.05) of glioma patients. Oncolytic viral therapy (VT) only extended patient survival in a subgroup analysis (HR = 0.60; 95% CI, 0.45-0.80; Z = -3.53; P = 0.0004 < 0.05). By contrast, immunopotentiation (IP) did not prolong OS (HR = 0.69; 95% CI, 0.50-0.96; Z = -2.23; P = 0.0256). Thus, DC vaccination significantly prolonged the OS of HGG patients, however, the efficacy of VT and IP should be explored in further studies. All the therapeutic schemes evaluated were associated with certain side effects. https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=112356.

Adoptive cell therapy for cancer treatment.

Adoptive cell therapy (ACT) is a rapidly growing anti-cancer strategy that has shown promise in treating various cancer types. The concept of ACT involves activating patients' own immune cells ex vivo and then transferring them back to the patients to recognize and eliminate cancer cells. Currently, the commonly used ACT includes tumor-infiltrating lymphocytes (TILs), genetically engineered immune cells, and dendritic cells (DCs) vaccines. With the advancement of cell culture and genetic engineering techniques, ACT has been used in clinics to treat malignant hematological diseases and many new ACT-based regimens are in different stages of clinical trials. Here, representative ACT approaches are introduced and the opportunities and challenges for clinical translation of ACT are discussed.

Potential of Personalized Dendritic Cell-Based Immunohybridoma Vaccines to Treat Prostate Cancer.

Prostate cancer (PCa) is the most commonly diagnosed cancer and the second most common cause of death due to cancer. About 30% of patients with PCa who have been castrated develop a castration-resistant form of the disease (CRPC), which is incurable. In the last decade, new treatments that control the disease have emerged, slowing progression and spread and prolonging survival while maintaining the quality of life. These include immunotherapies; however, we do not yet know the optimal combination and sequence of these therapies with the standard ones. All therapies are not always suitable for every patient due to co-morbidities or adverse effects of therapies or both, so there is an urgent need for further work on new therapeutic options. Advances in cancer immunotherapy with an immune checkpoint inhibition mechanism (e.g., ipilimumab, an anti-CTLA-4 inhibitor) have not shown a survival benefit in patients with CRPC. Other immunological approaches have also not given clear results, which has indirectly prevented breakthrough for this type of therapeutic strategy into clinical use. Currently, the only approved form of immunotherapy for patients with CRPC is a cell-based medicine, but it is only available to patients in some parts of the world. Based on what was gained from recently completed clinical research on immunotherapy with dendritic cell-based immunohybridomas, the aHyC dendritic cell vaccine for patients with CRPC, we highlight the current status and possible alternatives that should be considered in the future.

Prognostic survival biomarkers of tumor-fused dendritic cell vaccine therapy in patients with newly diagnosed glioblastoma

Dendritic cell (DC)-based immunotherapy has been applied to glioblastoma (GBM); however, biomarkers informing response remain poorly understood. We conducted a phase I/IIa clinical trial investigating tumor-fused DC (TFDC) immunotherapy following temozolomide-based chemoradiotherapy in patients with newly diagnosed GBM and determined prognostic factors in patients receiving TFDC immunotherapy. Twenty-eight adult patients with GBM isocitrate dehydrogenase (IDH) wild-type (IDH-WT) were enrolled; 127 TFDC vaccine injections (4.5 ± 2.6 times/patient) were administered. Patients with GBM IDH-WT had a respectable 5-year survival rate (24%), verifying the clinical activity of TFDC immunotherapy, particularly against O6-methylguanine-DNA methyltransferase (MGMT) unmethylated GBM (5-year survival rate: 33%). To identify novel factors influencing overall survival (OS) in GBM IDH-WT treated with TFDC immunotherapy, clinical parameters were assessed and comprehensive molecular profiling involving transcriptome and exome analyses was performed. MGMT promoter methylation status, extent of tumor resection, and vaccine parameters (administration frequency, DC and tumor cell numbers, and fusion ratio) were not associated with survival following TFDC immunotherapy. Old age and pre- and post-operative Karnofsky performance status were significantly correlated with OS. Low HLA-A expression and lack of CCDC88A, KRT4, TACC2, and TONSL mutations in tumor cells were correlated with better prognosis. We validated the activity of TFDC immunotherapy against GBM IDH-WT, including chemoresistant, MGMT promoter unmethylated cases. The identification of molecular biomarkers predictive of TFDC immunotherapy efficacy in GBM IDH-WT will facilitate the design of and patient stratification in a phase-3 trial to maximize treatment benefits.

Nanochannel Electro-Injection as a Versatile Platform for Efficient RNA/DNA Programming on Dendritic Cells.

The utilization of dendritic cell (DC) vaccines is a promising approach in cancer immunotherapy, and the modification of DCs for the expression of tumor-associated antigens is critical for successful cancer immunotherapy. A safe and efficient method for delivering DNA/RNA into DCs without inducing maturation is beneficial to achieve successful DC transformation for cell vaccine applications, yet remains challenging. This work presents a nanochannel electro-injection (NEI) system for the safe and efficient delivery of a variety of nucleic acid molecules into DCs. The device is based on track-etched nanochannel membrane as key components, where the nano-sized channels localize the electric field on the cell membrane, enabling lower voltage (<30V) for cell electroporation. The pulse conditions of NEI are examined so that the transfection efficiency (>70%) and biosafety (viability >85%) on delivering fluorescent dyes, plasmid DNA, messenger RNA, and circular RNA (circRNA) into DC2.4 are optimized. Primary mouse bone marrow DC can also be transfected with circRNA with 68.3% efficiency, but without remarkably affecting cellular viability or inducing DC maturation. These results suggest that NEI can be a safe and efficient transfection platform for in vitro transformation of DCs and possesses a promising potential for developing DC vaccines against cancer.

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.

An iPSC-derived exosome-pulsed dendritic cell vaccine boosts antitumor immunity in melanoma

Induced pluripotent stem cells (iPSCs) express a broad spectrum of tumor-associated antigens and exert prophylactic effects on various tumors. However, some problems remain, such as potential tumorigenicity, challenges in transport to the lymph nodes and spleen, and limited antitumor effects. Thus, designing a safe and effective iPSC-based tumor vaccine is necessary. We prepared iPSC-derived exosomes and incubated them with DCs (dendritic cells) for pulsing to explore their antitumor effects in murine melanoma models. The antitumor immune response induced by the DC vaccine pulsed with iPSC exosomes (DC+ EXO) was assessed invitro and invivo. After DC+ EXO vaccination, extracted spleen Tcells effectively killed a variety of tumor cells (melanoma, lung cancer, breast cancer, and colorectal cancer) invitro. In addition, DC+ EXO vaccination significantly inhibited melanoma growth and lung metastasis in mouse models. Furthermore, DC+ EXO vaccination induced long-term Tcell responses and prevented melanoma rechallenge. Finally, biocompatibility studies showed that the DC vaccine did not significantly alter the viability of normal cells and mouse viscera. Hence, our research may provide a prospective strategy of a safe and effective iPSC-based tumor vaccine for clinical use.

Results from the first step of a phase II study of vaccination with autologous dendritic cells loaded with autologous tumour homogenate in glioblastoma.

e14025 Background: Glioblastoma (GBM) is a poor prognosis malignant grade IV glioma. After surgical resection, standard therapy consists of concomitant radiotherapy (RT) and temozolomide (TMZ) followed by TMZ alone. Multiple phase I/II trials and at least 3 meta-analysis showed improved survival (OS) and progression free survival (PFS) with DC vaccination in High-grade gliomas (HGGs) patients (pts). In pts developing antitumor immunity, DC vaccination increases the amount of intratumoral activated cytotoxic T lymphocytes and decreases the number of FoxP3 positive regulatory T cells. Based on these data we have developed a phase II protocol with DC vaccine concomitant to standard RT-CT in pts who have undergone radical surgery for GBM. Methods: This is a single-arm, monocentric, phase II trial of a DC vaccination integrated to standard therapy in resected GBM pts. All pts receive a dendritic cell vaccine loaded with autologous tumor homogenate for up to one year. The vaccine administration starts at the end of the RT-CT (Induction Phase) and then is alternated to TMZ cycles (Maintenance Phase). Primary end points are PFS and safety, among secondary end points there are the in vitro (Elispot, Plasma Cytokines, Tumor tissue analysis) and in vivo (DTH skin test) Immune response evaluations. A Simon's two-stage design has been used for the sample size calculation. In the first stage, 9 patients have been accrued and a total of 28 patients will be enrolled at the end of the second step. Results: From July 2021, the 9 pts of the first step has been enrolled, 4 females and 5 males with median age of 58 years. Five pts had no MGMT mutation. All 9 pts concluded the induction phase. To November 2022 four pts have progressed with a median PFS, from the date of leukapheresis, of 6.5 months (3.2-NE). DTH test became positive in 5 out of 9 evaluable pts. Median OS from the date of surgery was 11 months. No gr 3-4 vaccine related toxicities have been observed and gr 1-2 toxicities were mostly due to local skin reactions. Conclusions: On the basis of the results described above and the vaccine favorable toxicity profile the Study Team decided to proceed with the second step. Clinical trial information: EUCTR220-003755-15 . [Table: see text]

Novel Immunotherapeutics: Perspectives on Checkpoints, Bispecifics, and Vaccines in Development.

Over the past decade, the advent of molecular techniques and deeper understanding of the tumor microenvironment (TME) have enabled the development of a multitude of immunotherapy targets and approaches. Despite the revolutionary advancement in immunotherapy, treatment resistance remains a challenge leading to decreased response rate in a significant proportion of patients. As such, there has recently been an evolving focus to enhance efficacy, durability, and toxicity profiles of immunotherapy. Although immune checkpoint inhibitors have revolutionized cancer treatment with many already-approved antibodies and several others in the pipeline, bispecific antibodies build on their success in an attempt to deliver an even more potent immune response against tumor cells. On the other hand, vaccines comprise the oldest and most versatile form of immunotherapy. Peptide and nucleic acid vaccines are relatively simple to manufacture compared with oncolytic virus-based vaccines, whereas the dendritic cell vaccines are the most complex, requiring autologous cell culture. Nevertheless, a crucial question in the development of cancer vaccines is the choice of antigen whereby shared and patient-private antigen approaches are currently being pursued. There is hope that cancer vaccines will join the repertoire of successful novel immunotherapeutics in the market. Better insights into the impact of immunotherapy on effector T cells and other immune cell populations in the TME shall be a major priority across the immune-oncology discipline and can help identify predictive biomarkers to evaluate response to treatment and identify patients who would most likely benefit from immunotherapy.

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 .

Phase I study of adoptive T cell therapy following HER2-pulsed dendritic cell vaccine and pepinemab/trastuzumab in patients with metastatic HER2-positive breast cancer (MBC).

TPS1113 Background: Despite major improvement of overall survival of HER2+ MBC with effective HER2 targeted therapies, many patients experience significant toxicities and develop progressive disease during treatment. Therefore, new and more effective therapeutic options are needed. This novel approach will evaluate whether the combination of three immunotherapies in addition to trastuzumab: dendritic cell (DC) vaccination, anti-SEMA4D blocking antibody (pepinemab) and CD4+ T cell adoptive transfer can lead to improved outcomes for patients with MBC refractory to HER2-targeted agents. BC have been considered as immunologically cold which is attributed to immune evasion and suppression of host effector immune cells homing into tumor bed. Progressive loss of Th1 immunity against HER2 oncodriver correlates with poor prognosis. HER2 peptide pulsed type I dendritic cells (HER2-DC1) restored anti-HER2 CD4+ Th1 immune response and improved pathologic complete response (pCR) in HER2+ BC. Antibodies to SEMA4D have been shown to modulate the TME by increasing effector cell infiltration and reducing immunosuppression. In preclinical studies, treatment with anti-SEMA4D and HER2-DC1 in mice bearing established HER2+ tumors improved DC homing, expansion of CD4+ T cells, and complete tumor regression, compared to treatment with anti-SEMA4D or HER2-DC1 alone. Further, subsequent expansion and adoptive transfer of CD4+ T cells induced synergistic anti-tumor activity by activating CD8+ T mediated cytotoxicity. Pepinemab was well-tolerated and showed signs of anti-tumor activity in in immunotherapy-resistant and PD-L1 negative/low non-small cell lung cancer patients when combined with checkpoint inhibitor (avelumab). Methods: This open label Phase 1 study is enrolling up to 28 patients with HER2+ MBC. Patients will be treated with 6 weekly injections of dendritic cell (DC1) vaccines in combination with trastuzumab and pepinemab. We hypothesize these therapies may elicit CD4+ HER2-specific T cell responses. HER2-specific T cells will be expanded ex vivo and subsequently infused to patients following lymphodepletion with cyclophosphamide. Trastuzumab and pepinemab will be given as maintenance in addition to booster DC1 vaccines. Patients (ECOG 0,1) must have had disease progression while on trastuzumab for the treatment of HER2+ MBC and received no more than 3 lines of chemotherapy in the setting of metastatic disease. Dose escalation will consist of 3-6 patients each with increasing amounts of transferred CD4+ T cells, followed by dose expansion of 10 patients at the MTD. The primary objective is safety and tolerability; secondary objectives will include evaluation of T cell immunity and immune subsets, efficacy, PK/PD/ADA of pepinemab, and biomarker assessments. Clinical trial information: NCT05378464 .

Final results of phase 2 trial of personal dendritic cell (DC) vaccines loaded with autologous tumor antigens (ATA) in newly diagnosed glioblastoma (GBM).

2047 Background: Standard GBM therapy is associated with early progression and poor overall survival (OS). DC-ATA AV-GBM-1, a personal vaccine consisting of autologous DC pulsed with ATA, was investigated in a multicenter trial in patients with newly diagnosed GBM. Methods: Key eligibility criteria for surgical collection of tumor were clinical suspicion of new primary GBM &amp; age 18-70 years. ATA lysate was prepared from irradiated tumor cells that were self-renewing in serum-free media. Autologous monocytes (MC) were collected by leukapheresis. Prior to initiating concurrent radiation therapy (RT) and temozolomide (TMZ), patients were enrolled with intent-to-treat (ITT) with DC-ATA after RT/TMZ. Eligibility included confirmation of primary GBM, availability of ATA &amp; MC, KPS &gt; 70 and plans for RT/TMZ. DC-ATA was manufactured during RT/TMZ. MC were differentiated into DC by culturing with IL-4 &amp; GM-CSF, then DC were incubated with ATA. DC-ATA was suspended in 500 mg GM-CSF just prior to s.c. injections at weeks 1, 2, 3, 8, 12,16, 20, &amp; 24 (8 doses). Patients were not excluded based on apparent disease progression or PFS. Standard adjuvant TMZ regimens were started after the 3 weekly injections. Primary endpoint was &gt; 75% OS 14.6 months from ITT enrollment. Secondary endpoints included median OS &amp; progression-free survival (PFS). Results: Cell line and MC collection were successful for 97% of patients. Median age of the 60 ITT enrollees was 59 years. 3 patients withdrew before starting DC-ATA; 57 received 392 injections; 68% received all 8. Most common AE attributed to DC-ATA were local injection site reactions (16%) &amp; flu-like symptoms (10%), but 33% experienced seizures. After 3 years of follow up, OS at 14.6 mos is 52.7% (95% CI 39.8,65.8), median OS 16.0 mos (95% CI 12.9,21.7) &amp; median PFS 10.4 mos (95% CI 8.6,11.6). OS rates at 1, 2, &amp; 3 years are 70.1%, 32.4%, &amp; 23.2%. Longer OS was associated with 8 DC-ATA doses (p &lt; 0.0001), on &lt; 2 mg/day dexamethasone (dex) at start of DC-ATA (p = 0.005), &gt; 6 cycles of adjuvant TMZ (p = 0.0054), &amp; KPS 90 or 100 (p = 0.010) at enrollment. Independent variables per multivariate Cox regression analysis were 8 DC-ATA doses, dex dose, IDH mutated, TMZ &gt; 6 cycles, &amp; MGMT promoter methylated. Concurrent TMZ regimens included TMZ alone (n = 28), TMZ + anti-VEGF(n = 14), &amp; TMZ + tumor treating fields (TTF) (n = 10); 8 received no concurrent TMZ. OS was longer in patients treated with concurrent TMZ alone compared to no TMZ (p = 0.0003), TMZ + anti-VEGF (p = 0.045) or TMZ + TTF (p = 0.045). The only common features among 7 patients progression-free at 3 years are 8 DC-ATA injections, age &lt; 60, &amp; &lt; 2 mg dex. Conclusions: DC-ATA was reliably produced and injections well-tolerated in combination with various TMZ-based regimens, but the primary OS objective was not achieved. PFS was encouraging, but did not translate into improved OS, perhaps because DC-ATA was limited to 8 injections. Clinical trial information: NCT03400917 .

Approaches to the development of the dendritic cell and neoantigen-based antitumor vaccines

Approaches to the development of the dendritic cell and neoantigen-based antitumor vaccines

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 .

Discovery of highly immunogenic spleen-resident FCGR3+CD103+ cDC1s differentiated by IL-33-primed ST2+ basophils

Recombinant interleukin-33 (IL-33) inhibits tumor growth, but the detailed immunological mechanism is still unknown. IL-33-mediated tumor suppression did not occur in Batf3−/− mice, indicating that conventional type 1 dendritic cells (cDC1s) play a key role in IL-33-mediated antitumor immunity. A population of CD103+ cDC1s, which were barely detectable in the spleens of normal mice, increased significantly in the spleens of IL-33-treated mice. The newly emerged splenic CD103+ cDC1s were distinct from conventional splenic cDC1s based on their spleen residency, robust effector T-cell priming ability, and surface expression of FCGR3. DCs and DC precursors did not express Suppressor of Tumorigenicity 2 (ST2). However, recombinant IL-33 induced spleen-resident FCGR3+CD103+ cDC1s, which were found to be differentiated from DC precursors by bystander ST2+ immune cells. Through immune cell fractionation and depletion assays, we found that IL-33-primed ST2+ basophils play a crucial role in the development of FCGR3+CD103+ cDC1s by secreting IL-33-driven extrinsic factors. Recombinant GM-CSF also induced the population of CD103+ cDC1s, but the population neither expressed FCGR3 nor induced any discernable antitumor immunity. The population of FCGR3+CD103+ cDC1s was also generated in vitro culture of Flt3L-mediated bone marrow-derived DCs (FL-BMDCs) when IL-33 was added in a pre-DC stage of culture. FL-BMDCs generated in the presence of IL-33 (FL-33-DCs) offered more potent tumor immunotherapy than control Flt3L-BMDCs (FL-DCs). Human monocyte-derived DCs were also more immunogenic when exposed to IL-33-induced factors. Our findings suggest that recombinant IL-33 or an IL-33-mediated DC vaccine could be an attractive protocol for better tumor immunotherapy.

Advances in Immunotherapy and Vaccine for Prostate Cancer

Prostate cancer is one of the most common malignant tumors of the urinary system. The incidence of prostate cancer is high in the elderly male patients, which seriously threatens the life and health. In recent years, immunotherapy to activate anti-cancer host immune cells to kill tumors has become a new area of research for the treatment of prostate cancer. As an important component of immunotherapy, cancer vaccines have a unique position in the precise treatment of malignant tumors. There are many types of prostate cancer vaccines, including monocyte vaccines, dendritic cell vaccines, viral vaccines, peptide vaccines, and DNA/mRNA vaccines, etc. As the most important cancer vaccine based on monocytes, it is the only prostate cancer therapeutic vaccine approved by the US Food and Drug Administration at present, which plays an extremely important role in the immunotherapy of prostate cancer. However, due to its own limitations, SipuleucelT has not been widely adopted. Currently, the complexity of immunotherapy and the specificity of prostate cancer mean that other prostate cancer vaccines have not shown expected clinical benefits in large randomized phase II and III trials, and further in-depth studies are still needed.

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.