Our hypothesis is that determination of the optimal dosing regimen of a potential therapeutic in terms of its molecular and cellular responses in vivo will greatly improve the likelihood of a beneficial outcome in future clinical trials. We are testing the utility of this approach in the ongoing investigation of the effects of ultra-low doses of IL-2 in patients with type 1 diabetes (T1D) (https://www.ncbi.nlm.nih.gov/pubmed/27727279) and with vasculitis, and will consider and evaluate other potential therapeutics.
In the last five years we have been developing and undertaking experimental medicine studies in patients with T1D to investigate in detail the in vivo effects of the potential therapy, ultra-low dosing of IL-2 (https://www.ncbi.nlm.nih.gov/pubmed/27727279). We aim to continue and develop this approach in establishing the long-term effects of regular IL-2 dosing not only on the immune system (flow cytometry and other assay methods, including singe-cell genomics) but also on metabolism (C-peptide production) in children.
In parallel, we have established a collaboration with colleagues in Germany and the Helmsley Charitable Trust an international randomised control trial in T1D to prevent the initial autoimmunity to insulin (the primary, genetic autoantigen in T1D) by daily ingestion of oral insulin to promote immune tolerance to insulin in newborn children in order to delay onset (impaired beta-cell function) and diagnosis of the disease (https://www.ncbi.nlm.nih.gov/pubmed/27069865).
This project, developing and applying approaches to translational medicine is suitable for a trainee clinician who is interested in research and who aims to be a clinical scientist, for a rotation project, MPhil or DPhil.
To undertake experimental and statistical analyses in our IL-2 and oral insulin clinical trials and assess the effects of these potential therapeutics.
There will be opportunity to learn and develop skills in experimental medicine approaches, bioinformatics, statistics and a wide range of molecular, metabolic and immunological techniques.
Project reference number: 880
|Professor John A Todd FRS FMedSci||Wellcome Trust Centre for Human Genetics||Oxford University, Henry Wellcome Building of Genomic Medicine||GBRfirstname.lastname@example.org|
BACKGROUND: Interleukin-2 (IL-2) has an essential role in the expansion and function of CD4+ regulatory T cells (Tregs). Tregs reduce tissue damage by limiting the immune response following infection and regulate autoreactive CD4+ effector T cells (Teffs) to prevent autoimmune diseases, such as type 1 diabetes (T1D). Genetic susceptibility to T1D causes alterations in the IL-2 pathway, a finding that supports Tregs as a cellular therapeutic target. Aldesleukin (Proleukin; recombinant human IL-2), which is administered at high doses to activate the immune system in cancer immunotherapy, is now being repositioned to treat inflammatory and autoimmune disorders at lower doses by targeting Tregs. METHODS AND FINDINGS: To define the aldesleukin dose response for Tregs and to find doses that increase Tregs physiologically for treatment of T1D, a statistical and systematic approach was taken by analysing the pharmacokinetics and pharmacodynamics of single doses of subcutaneous aldesleukin in the Adaptive Study of IL-2 Dose on Regulatory T Cells in Type 1 Diabetes (DILT1D), a single centre, non-randomised, open label, adaptive dose-finding trial with 40 adult participants with recently diagnosed T1D. The primary endpoint was the maximum percentage increase in Tregs (defined as CD3+CD4+CD25highCD127low) from the baseline frequency in each participant measured over the 7 d following treatment. There was an initial learning phase with five pairs of participants, each pair receiving one of five pre-assigned single doses from 0.04 × 106 to 1.5 × 106 IU/m2, in order to model the dose-response curve. Results from each participant were then incorporated into interim statistical modelling to target the two doses most likely to induce 10% and 20% increases in Treg frequencies. Primary analysis of the evaluable population (n = 39) found that the optimal doses of aldesleukin to induce 10% and 20% increases in Tregs were 0.101 × 106 IU/m2 (standard error [SE] = 0.078, 95% CI = -0.052, 0.254) and 0.497 × 106 IU/m2 (SE = 0.092, 95% CI = 0.316, 0.678), respectively. On analysis of secondary outcomes, using a highly sensitive IL-2 assay, the observed plasma concentrations of the drug at 90 min exceeded the hypothetical Treg-specific therapeutic window determined in vitro (0.015-0.24 IU/ml), even at the lowest doses (0.040 × 106 and 0.045 × 106 IU/m2) administered. A rapid decrease in Treg frequency in the circulation was observed at 90 min and at day 1, which was dose dependent (mean decrease 11.6%, SE = 2.3%, range 10.0%-48.2%, n = 37), rebounding at day 2 and increasing to frequencies above baseline over 7 d. Teffs, natural killer cells, and eosinophils also responded, with their frequencies rapidly and dose-dependently decreased in the blood, then returning to, or exceeding, pretreatment levels. Furthermore, there was a dose-dependent down modulation of one of the two signalling subunits of the IL-2 receptor, the β chain (CD122) (mean decrease = 58.0%, SE = 2.8%, range 9.8%-85.5%, n = 33), on Tregs and a reduction in their sensitivity to aldesleukin at 90 min and day 1 and 2 post-treatment. Due to blood volume requirements as well as ethical and practical considerations, the study was limited to adults and to analysis of peripheral blood only. CONCLUSIONS: The DILT1D trial results, most notably the early altered trafficking and desensitisation of Tregs induced by a single ultra-low dose of aldesleukin that resolves within 2-3 d, inform the design of the next trial to determine a repeat dosing regimen aimed at establishing a steady-state Treg frequency increase of 20%-50%, with the eventual goal of preventing T1D. TRIAL REGISTRATION: ISRCTN Registry ISRCTN27852285; ClinicalTrials.gov NCT01827735. Hide abstract