Vaccination with autologous dendritic cells pulsed with multiple tumor antigens for treatment of patients with malignant melanoma: results from a phase I/II trial.

BACKGROUND AND AIM: Dendritic cells are regarded as the most effective antigen presenting cells and coordinators of the immune response and therefore suitable as vaccine basis. Here we present results from a clinical study in which patients with malignant melanoma (MM) with verified progressive disease received vaccination with autologous monocyte-derived mature dendritic cells (DC) pulsed with p53, survivin and telomerase-derived peptides (HLA-A2+ patients) or with autologous/allogeneic tumor lysate (HLA-A2(−) patients) in combination with low-dose interleukin (IL)-2 and interferon (IFN)-alpha2b. RESULTS: Of 46 patients who initiated treatment, 10 stopped treatment within 1-4 weeks because of rapid disease progression and deterioration. After 8 weeks, 36 patients were evaluable: no patient had an objective response, 11 patients had stable disease (SD); six had continued SD after 4 months, and three patients had prolonged SD for more than 6 months. The mean overall survival time was 9 months, with a significantly longer survival (18.4 months) of patients who attained SD compared with patients with progressive disease (PD) (5 months). Induction of antigen-specific T-cell responses was analyzed by multidimensional encoding of T cells using HLA-A2 major histocompatibility complex (MHC) multimers. Immune responses against five high-affinity vaccine peptides were detectable in the peripheral blood of six out of 10 analyzed HLA-A2+ patients. There was no observed correlation between the induction of immune responses and disease stabilization. A significant lower blood level of regulatory T cells (CD25(high) CD4 T cells) was demonstrable after six vaccinations in patients with SD compared with PD. CONCLUSIONS: Vaccination was feasible and safe. Treatment-associated SD was observed in 24% of the patients. SD correlated with prolonged survival suggesting a clinical benefit. Differences in the level of regulatory T cells among SD and PD patients could indicate a significant role of these immune suppressive cells.

Increase of circulating CD4+CD25highFoxp3+ regulatory T cells in patients with metastatic renal cell carcinoma during treatment with dendritic cell vaccination and low-dose interleukin-2.

Regulatory T cells (Treg) play an important role in the maintenance of immune tolerance and may be one of the obstacles of successful tumor immunotherapy. In this study, we analyzed the impact of administration of dendritic cell (DC) vaccination in combination with low-dose interleukin (IL)-2 in patients with metastatic renal cell carcinoma on the frequency of CD4+CD25highFoxp3+ Treg cells in peripheral blood. We found that the treatment increased the frequency of Treg cells more than 7-fold compared with pretreatment levels (P<0.0001). The frequency of Treg cells decreased when patients had been off IL-2 treatment for only 8 days, but remained higher than pretreatment levels. A functional assay showed that isolated Treg cells were capable of inhibiting proliferation of responder cells. Also, in vitro studies showed that coculture of mature DCs, autologous T cells and IL-2 leads to an increase in the number of Treg cells whereas IL-21 does not stimulate the induction of Treg cells. These findings demonstrate that even low doses of IL-2 in combination with DC vaccination are able to expand CD4+CD25+Foxp3+ Treg cells in vivo in metastatic renal cell carcinoma patients. Further, the results indicate that the IL-2-induced effect on Treg cells is reversible and declines shortly after termination of IL-2 treatment. Our data suggest that approaches combining DC-mediated immunotherapy and depletion of Treg cells may be necessary to enhance the ability of vaccination therapy to elicit effective antitumor responses in cancer patients. Also, adjuvant IL-21 administration may lead to immune enhancement without simultaneous induction of Treg cells.

Therapeutic dendritic cell vaccination of patients with metastatic renal cell carcinoma: a clinical phase 1/2 trial.

Therapeutic dendritic cell (DC) vaccination against cancer is a strategy aimed at activating the immune system to recognize and destroy tumor cells. In this nonrandomized phase 1/2 trial, we investigated the safety, feasibility, induction of T-cell response, and clinical response after treatment with a DC-based vaccine in patients with metastatic renal cell carcinoma. Twenty-seven patients with progressive cytokine-refractory metastatic renal cell carcinoma were vaccinated with DCs loaded with either a cocktail of survivin and telomerase peptides or tumor lysate depending on their HLA-A2 haplotype, and low-dose IL-2 was administered concomitantly. Tumor response, immune response, and serum IL-6 and YKL-40 were measured during treatment. Vaccine generation was successful in all patients and no serious adverse events were observed. None of the patients had an objective response but 13/27 patients obtained disease stabilization (SD) for more than 8 weeks. An antigen-specific immune response was demonstrated in 6/6 patients tested. Furthermore, significant alterations in serum YKL-40 and IL-6 were found during treatment. In conclusion, DC vaccination in our setting is feasible and without severe toxicity. Almost half of the patients obtained SD, and in more than 1/3 of the patients, SD persisted for more than 6 months. However, the evaluation of SD is difficult to interpret in the absence of a randomized trial and, therefore, these results should be interpreted with caution. Antigen-specific immune responses were observed in a subset of the treated patients.

Comparison of alpha-Type-1 polarizing and standard dendritic cell cytokine cocktail for maturation of therapeutic monocyte-derived dendritic cell preparations from cancer patients.

The current "gold standard" for generation of dendritic cell (DC) used in DC-based cancer vaccine studies is maturation of monocyte-derived DCs with tumor necrosis factor-alpha (TNF-alpha)/IL-1beta/IL-6 and prostaglandin E(2) (PGE(2)). Recently, a protocol for producing so-called alpha-Type-1 polarized dendritic cells (alphaDC1) in serum-free medium was published based on maturation of monocyte-derived DCs with TNF-alpha/IL-1-beta/polyinosinic:polycytidylic acid (poly-I:C)/interferon (IFN)-alpha and IFN-gamma. This DC maturation cocktail was described to fulfill the criteria for optimal DC generation and to be superior to the standard DC (sDC) cocktail as it induced fully mature DCs with potent IL-12p70 secretion together with CCR7 expression which is necessary for priming of a TH1 response and for migration to the draining lymph node, respectively. In this study, we tested the adaptation of alphaDC1 maturation cocktail to a protocol for clinical grade DC generation from cancer patients performed in X-VIVO 15 medium. We showed that alphaDC1 in this protocol induce lower up-regulation of CD83 and several other maturation markers, co-stimulatory molecules and CCR7 together with higher up-regulation of inhibitory molecules such as PD-L1, ILT2, ILT3 as compared to sDC. Although alphaDC1 matured DCs secreted more IL-12p70 and IL-23 these DCs had lower or similar stimulatory capacity compared to sDCs when used as stimulating cells in mixed lymphocyte reaction (MLR) or for induction of autologous influenza antigen specific T lymphocytes. Thus, our observations underline that alphaDC1 maturation cannot be directly adapted to alternative protocols for DC generation. Also, this study indicates the necessity for further investigation of correlation between in vitro DC parameters and their in vivo efficacy in clinical vaccination trials.

Identification of a new hTERT-derived HLA-A*0201 restricted, naturally processed CTL epitope.

By the use of a neural network capable of performing quantitative predictions of peptides binding to HLA-A*0201 molecules, we identified a number of nonamer peptides derived from the catalytic subunit of telomerase, human telomerase reverse transcriptase (hTERT). Five nonimmunogenic peptides with measured binding affinities for HLA-A*0201 ranging from 155 to 1,298 nM were modified at the P1, P2 and P9 positions, respectively, to achieve stronger HLA-A*0201 binding. One peptide, mp30-38 (mp30), with an L to V substitution at position 9 was subsequently found to be immunogenic in mp30 immunized HLA-A*0201/H2K(b) or HHD transgenic mice. The T cell reactivity obtained was directed against both the mp30 and against the unmodified p30. Anti-mp30 specific T cells generated in HLA-A*0201 transgenic mice were dependent on TCR-CD8/MHC-I alpha3 binding and therefore not capable of recognizing mp30-pulsed human HLA-A*0201(+) cells or murine HLA-A*0201 transfectants. In order to show reactivity against naturally processed peptide in human tumor cells, an hTERT positive HLA-A*0201 negative colon carcinoma cell line (CCL220) was transfected with an HLA-A*0201/H2K(b) cDNA construct and used as target in ELISPOT and cytotoxicity assays. The data show that T cells from mp30 immunized HHD transgenic mice react specifically against the CCL220 transfectant indicating that p30 is naturally processed. In conclusion, we have identified a new CTL HLA-A*0201 restricted hTERT epitope, which is now, included in an ongoing phase 2 vaccine trial of patients with disseminated cancer.

Therapeutic dendritic cell vaccination of patients with renal cell carcinoma.

OBJECTIVE: Dendritic cell (DC) vaccination against cancer is a new specific immunotherapeutic approach given with either therapeutic or adjuvant intent. We provide a review of DC vaccination as a treatment for metastatic renal cell carcinoma (RCC). METHOD: A total of 197 patients with metastatic RCC were treated with DC vaccination in 14 phase I/II clinical trials. Different vaccine preparations, administration routes, and treatment schedules have been tested in these trials. Clinical response and immune response were analysed. RESULTS: Seventy-three (37%) patients had clinical response with 4 complete responses, 8 partial responses and 61 disease stabilisations, whereas 4 patients had mixed response, but most of these responses have not been transformed into durable clinical effects. Immune responses were observed in a subset of the treated patients but were not always associated with a clinical response. Only mild toxicity was observed in these trials. CONCLUSION: DC vaccination therapy in patients with metastatic RCC is currently experimental but the results are encouraging with achievement of tumour regression and induction of antigen-specific immune response combined with minimal toxicity in a subset of the treated patients. Future emphasis should be placed on therapy in the adjuvant setting because patients with minimal residual disease are more likely to benefit from the treatment. Combination approaches with DC vaccination and immune-enhancing therapies or antiangiogenic therapy should be further investigated to develop new and more efficient treatment strategies for patients with RCC.

[Dendrite cell-based cancer vaccines--clinical application]. / Dendritcellebaserede cancervacciner--klinisk anvendelse.

Dendritic cell (DC)-based vaccination against cancer is a specific immunotherapy with a new therapeutic approach for patients with cancer. Preclinical and clinical trials, in which more than 1,000 cancer patients received dendritic cell vaccination, have shown that it is possible to activate the immune system against cancer cells and to induce a clinical response in some of the patients. The treatment is so far experimental, and there is a need for well-designed trials that aim to improve the DC vaccine approach.

Elevated plasma interleukin-18 is a marker of insulin-resistance in type 2 diabetic and non-diabetic humans.

Elevated plasma IL-18 is present in several conditions sharing insulin-resistance as common trait, but the association with insulin-resistance per se is not established. Plasma/serum IL-6, IL-18, TNF-alpha, soluble TNF receptor II (sTNFR2), and C-reactive protein (CRP) were measured in 97 patients with type 2 diabetes (DM) and 84 non-diabetic controls (CON). The association with insulin-resistance-estimated using the homeostasis model assessment (HOMA-IR)-was analyzed using multivariate linear and logistic regression. Compared to CON, DM demonstrated higher plasma levels of IL-18 (P = 0.001), IL-6 (P < 0.001), sTNFR2 (P = 0.005), and CRP (P < 0.001), while TNF-alpha was lower (P = 0.017). Plasma IL-18 increased across HOMA-IR quartiles in both DM and CON, both with and without adjustment for confounders (all P < 0.05). In contrast, neither IL-6, TNF-alpha, sTNFR2, nor CRP was associated with HOMA-IR in CON when adjusting for confounders. Accordingly, 50% increase of IL-18 corresponded to a marked increase of HOMA-IR in both DM and CON (DM: 26%, P = 0.014; CON: 25%, P = 0.003) after adjustment for confounders. Our results show that plasma IL-18 was associated with HOMA-IR independent of obesity and type 2 diabetes.