Safety and feasibility of intradermal injection with tolerogenic dendritic cells pulsed with proinsulin peptide—for type 1 diabetes

Induction or restoration of immune tolerance is the holy grail in type 1 diabetes.1Roep BO Wheeler DCS Peakman M Antigen-based immune modulation therapy for type 1 diabetes: the era of precision medicine.Lancet Diabetes Endocrinol. 2019; 7: 65-74Summary Full Text Full Text PDF PubMed Scopus (52) Google Scholar However, non-specific immunotherapies to control the T-cell dependent autoimmune response in type 1 diabetes show substantial side-effects and only temporarily modulate the course of the disease.2Atkinson MA Roep BO Posgai A Wheeler DCS Peakman M The challenge of modulating β-cell autoimmunity in type 1 diabetes.Lancet Diabetes Endocrinol. 2019; 7: 52-64Summary Full Text Full Text PDF PubMed Scopus (57) Google Scholar Preferably, therapy should be effective long term to selectively target and regulate β-cell autoimmunity. Tolerogenic dendritic cells (tolDCs) are considered as an attractive approach to modulate autoimmune diseases in an antigen-specific manner and to intervene in the pathogenesis of type 1 diabetes.3Nikolic T Roep BO Regulatory multitasking of tolerogenic dendritic cells-lessons taken from vitamin d3-treated tolerogenic dendritic cells.Front Immunol. 2013; 4: 113Crossref PubMed Scopus (71) Google Scholar Naturally derived proinsulin peptide C19-A3 has been shown to be safe4Alhadj Ali M Liu YF Arif S et al.Metabolic and immune effects of immunotherapy with proinsulin peptide in human new-onset type 1 diabetes.Sci Transl Med. 2017; 9eaaf7779Crossref PubMed Scopus (98) Google Scholar and to elicit immune responses in patients with type 1 diabetes; and tolDCs presenting this peptide can induce proinsulin-specific regulatory T cells.5Kleijwegt FS Jansen DT Teeler J et al.Tolerogenic dendritic cells impede priming of naïve CD8+ T cells and deplete memory CD8+ T cells.Eur J Immunol. 2013; 43: 85-92Crossref PubMed Scopus (35) Google Scholar, 6Beringer DX Kleijwegt FS Wiede F et al.T cell receptor reversed polarity recognition of a self-antigen major histocompatibility complex.Nat Immunol. 2015; 16: 1153-1161Crossref PubMed Scopus (82) Google Scholar Therefore, we aimed to assess the clinical applicability of proinsulin peptide loaded tolDCs in a safety and feasibility trial in patients with type 1 diabetes (D-Sense trial). Here, we present the safety and feasibility data of a first-in-man prospective, open label, placebo-controlled, dose escalation, phase 1 trial in nine patients with long-standing type 1 diabetes. TolDCs pulsed with proinsulin peptide were administered by two intradermal vaccination series (ie, 5, 10, or 20 intradermal injections depending on the dose cohort), according to the prime-boost protocol, 1 month apart (appendix p 2). Feasibility and safety (appendix pp 5, 8–9) were assessed for doses of 5 × 106, 10 × 106, and 20 × 106 tolDCs per injection series. After screening and selection (appendix p 1, 7), study participants underwent leukapheresis (duration varying between 173–376 min), to collect a sufficient number of leukocytes for CD14+ monocyte selection and generation and cryopreservation of immature tolDCs (appendix p 8). Immature tolDCs were thawed 2 days before intradermal administration, and subsequently matured and loaded with proinsulin peptide C19-A3 to yield tolDC products, fulfilling all required and validated release criteria (appendix p 8). The projected doses of 5, 10, or 20 million tolDCs per injection were successfully administered in eight patients; for one patient in the highest dose group only 19 million tolDCs (instead of the 20 million) could be obtained per injection. Patients were extensively monitored after leukapheresis and for 6 months after the tolDC injection. Besides typical and reversible leukapheresis-related discomforts, administration of tolDCs caused a mild stinging and local non-itchy redness of the skin (erythema) at the injection site. In patients receiving both vehicle and tolDC injections these symptoms were slightly more pronounced with tolDCs compared with injections containing only saline (figure 1A). The redness largely reduced in the first hour after injection and disappeared within 24 h, leaving a small bulgy blister-like injection scar of 1–3 mm in diameter. Skin reactions (erythema) were variable among patients, and more evident in patients that reported being familiar with dermatographia (skin writing). However, skin reactions did not differ depending on the tolDC dose and disappeared completely within 1–2 weeks, never requiring medical intervention. In total 13 adverse events were recorded in 7 patients: three grade 2 events and ten grade 1 events (appendix p 9). Grade 2 adverse events were allergic rhinitis, cold, and toothache which occurred 2 to 3 months after injection but were not considered related to the tolDC injection. Grade 1 adverse events such as fatigue were noted in two patients receiving the lowest tolDC dose in the time period between leukapheresis and tolDC injection. Two patients showed decreased leucocytes and mild eosinophilia in the intermediate dose group, and dry skin and arthralgia were noted in one patient in the highest dose group (appendix p 9). Registered events had resolved in the monitoring period without requiring additional intervention. Finally, minor deviations from the reference range in blood chemistry were registered (appendix p 9) at the last monitoring appointment and appeared to be reversible, and not part of any morbidity as shown outside of the study follow-up. β-cell function and overall diabetic control remained stable during the 6 months of extensive monitoring. All patients maintained tight glycaemic control after tolDC treatment with stable HbA1c values, unchanged insulin requirements, and a similar number of weakly hypoglycaemic events as before the trial, until the last follow-up visit (figure 1B). This finding was irrespective of the administered tolDC dose. Residual β-cell function was assessed by a mixed-meal tolerance test before and after the tolDC injection. Of the nine patients included in the study, three had detectable stimulated C-peptide that did not change after tolDC treatment. This low rate of residual β-cell function was expected given our safety-driven strategy of choosing only patients with long standing type 1 diabetes (on average more than 12 years with the disease) for this first-in-man trial. Prime-boost intradermal vaccination containing up to 20 million proinsulin-epitope loaded tolDCs per injection coincided with low grade, acceptable toxicity which was not likely related to the therapy. Most importantly, there were no signs of systemic immune suppression, no induction of allergy to insulin, no interference with insulin therapy, and no accelerated loss in β-cell function in patients with the remaining C-peptide. In conclusion, generation and intradermal administration of autologous tolDCs pulsed with proinsulin peptide appears feasible and safe. Our results warrant subsequent clinical testing in patients with a shorter diagnosis of type 1 diabetes and with preserved C-peptide production, to assess whether this novel immune intervention strategy is able to delay or halt progressive loss of β-cell function. Further testing would tell whether antigen-specific immunomodulation using tolDCs protects β cells from autoimmune destruction and can act as curative therapy for type 1 diabetes. The study was financially supported by the European Union ( FP7-NAIMIT , 241447 ), the Dutch Diabetes Research Foundation, and the DON Foundation (expert center grant, 2013·40·1693). BOR is a director of the Wanek Family Project for type 1 diabetes. We thank our participating patients and colleagues from the Leiden University Medical Center hemapheresis clinical research unit; and Petra Sonneveld, Sandra Laban, and Joris Wesselius from the diabetes research lab for their expert help in planning and executing our clinical trial. We acknowledge the contribution of our distinguished Data Safety Monitoring Board members Anette-Gabriele Ziegler (chair), Ranjeny Thomas, and Dick P Engberts. Download .pdf (.24 MB) Help with pdf files Supplementary appendix