Skewing effect of sulprostone on dendritic cell maturation compared with dinoprostone.

BACKGROUND: Dendritic cells (DCs) are the most efficient antigen-presenting cells and act at the center of the immune system owing to their ability to control both immune tolerance and immunity. In cancer immunotherapy, DCs play a key role in the regulation of the immune response against tumors and can be generated ex vivo with different cytokine cocktails. METHODS: We evaluated the feasibility of dinoprostone (PGE2) replacement with the molecular analog sulprostone, in our good manufacturing practice (GMP) protocol for the generation of DC-based cancer vaccine. We characterized the phenotype and the function of DCs matured in the presence of sulprostone as a potential substitute of dinoprostone in the pro-inflammatory maturation cocktail consisting of tumor necrosis factor alpha (TNF-α), interleukin-1 beta (IL-1ß) and IL-6. RESULTS: We found that sulprostone invariably reduces the recovery, but does not significantly modify the viability and the purity of DCs. The presence of sulprostone in the maturation cocktail increases the adhesion of single cells and of clusters of DCs to the flask, making them more similar to their immature counterpart in terms of adhesion and spreading proprieties. Moreover, we observed that sulprostone impairs the expression of co-stimulatory molecules and the spontaneous as well as the directed migration capacity of DCs. DISCUSSION: These findings underscore that the synthetic analog sulprostone strongly reduces the functional quality of DCs, thus cannot replace dinoprostone in the maturation cocktail of monocyte-derived DCs.

Vaccination with autologous dendritic cells loaded with autologous tumor lysate or homogenate combined with immunomodulating radiotherapy and/or preleukapheresis IFN-α in patients with metastatic melanoma: a randomised "proof-of-principle" phase II study.

BACKGROUND: Vaccination with dendritic cells (DC) loaded with tumor antigens elicits tumor-specific immune responses capable of killing cancer cells without inducing meaningful side-effects. Patients with advanced melanoma enrolled onto our phase II clinical studies have been treated with autologous DC loaded with autologous tumor lysate/homogenate matured with a cytokine cocktail, showing a clinical benefit (PR + SD) in 55.5% of evaluable cases to date. The beneficial effects of the vaccine were mainly restricted to patients who developed vaccine-specific immune response after treatment. However, immunological responses were only induced in about two-thirds of patients, and treatments aimed at improving immunological responsiveness to the vaccine are needed. METHODS/DESIGN: This is a phase II, "proof-of-principle", randomized, open-label trial of vaccination with autologous DC loaded with tumor lysate or homogenate in metastatic melanoma patients combined with immunomodulating RT and/or preleukapheresis IFN-α. All patients will receive four bi-weekly doses of the vaccine during the induction phase and monthly doses thereafter for up to a maximum of 14 vaccinations or until confirmed progression. Patients will be randomized to receive:(1.) three daily doses of 8 Gy up to 12 Gy radiotherapy delivered to one non-index metastatic field between vaccine doses 1 and 2 and, optionally, between doses 7 and 8, using IMRT-IMAT techniques;(2.) daily 3 MU subcutaneous IFN-α for 7 days before leukapheresis;(3.) both 1 and 2;(4.) neither 1 nor 2.At least six patients eligible for treatment will be enrolled per arm. Daily 3 MU IL-2 will be administered subcutaneously for 5 days starting from the second day after each vaccine dose. Serial DTH testing and blood sampling to evaluate treatment-induced immune response will be performed. Objective response will be evaluated according to immune-related response criteria (irRC). DISCUSSION: Based upon the emerging role of radiotherapy as an immunologic modifier, we designed a randomized phase II trial adding radiotherapy and/or preleukapheresis IFN-α to our DC vaccine in metastatic melanoma patients. Our aim was to find the best combination of complementary interventions to enhance anti-tumor response induced by DC vaccination, which could ultimately lead to better survival and milder toxicity.

Complementary vaccination protocol with dendritic cells pulsed with autologous tumour lysate in patients with resected stage III or IV melanoma: protocol for a phase II randomised trial (ACDC Adjuvant Trial).

INTRODUCTION: Surgery is one of the treatments of choice for patients with a single metastasis from melanoma but is rarely curative. Such patients could potentially benefit from consolidation immunotherapy. Vaccination with dendritic cells (DCs) loaded with tumour antigens elicits a tumour-specific immune response. In our experience, patients who developed delayed type hypersensitivity (DTH) after DC vaccination showed a median overall survival (OS) of 22.9 monthsvs4.8 months for DTH-negative cases. A phase II randomised trial showed an advantage OS of a DC vaccine over a tumour cell-based vaccine (2-year OS 72% vs31%, respectively). Given that there is no standard therapy after surgical resection of single metastases, we planned a study to compare vaccination with DCs pulsed with autologous tumour lysate versus follow-up. METHODS AND ANALYSIS: This is a randomised phase II trial in patients with resected stage III/IV melanoma. Assuming a median relapse-free survival (RFS) of 7.0 months for the standard group and 11.7 months for the experimental arm (HR 0.60), with a two-sided tailed alpha of 0.10, 60 patients per arm must be recruited. An interim futility analysis will be performed at 18 months. The DC vaccine, produced in accordance with Good Manufacturing Practice guidelines, consists of autologous DCs loaded with autologous tumour lysate and injected intradermally near lymph nodes. Vaccine doses will be administered every 4 weeks for six vaccinations and will be followed by 3 million unit /day of interleukin-2 for 5 days. Tumour restaging, blood sampling for immunological biomarkers and DTH testing will be performed every 12 weeks. ETHICS AND DISSEMINATION: The protocol, informed consent and accompanying material given to patients were submitted by the investigator to the Ethics Committee for review. The local Ethics Committee and the Italian Medicines Agency approved the protocol (EudraCT code no.2014-005123-27). Results will be published in a peer-reviewed international scientific journal. TRIAL REGISTRATION NUMBER: 2014-005123-27.

Dendritic cell vaccination for metastatic melanoma: a 14-year monoinstitutional experience.

Although immunomodulating antibodies are highly effective in metastatic melanoma, their toxicity, related to the activation of T lymphocytes, can be severe. Anticancer vaccines promote a fairly specific response and are very well tolerated, but their effectiveness has yet to be demonstrated. We have been treating patients with advanced melanoma with an autologous dendritic cell vaccine since 2001; to better characterize the safety and efficacy of our product, we designed a retrospective study on all of our patients treated with the vaccine to date. We retrospectively reviewed both case report forms of patients included in clinical trials and medical records of those treated within a compassionate use program. Response was assessed according to the Response Evaluation Criteria In Solid Tumors criteria and toxicity has been graded according to CTCAE 4.0. Although the response rate has been rather low, the median overall survival of 11.4 months and the 1-year survival rate of 46.9% are encouraging, especially considering the fact that data were obtained in a heavily pretreated population and only about one quarter of the patients had received ipilimumab and/or BRAF inhibitors. Multivariate analysis confirmed that the development of an immune response was significantly correlated with a better prognosis (hazard ratio 0.54; P=0.019). The adverse events observed were generally mild and self-limiting. Our analysis confirms the excellent tolerability of our vaccine, making it a potential candidate for combination therapies. As efficacy seems largely restricted to immunoresponsive patients, future strategies should aim to increase the number of these patients.