Low-dose interleukin 2 for the reduction of vascular inflammation in acute coronary syndromes (IVORY): protocol and study rationale for a randomised, double-blind, placebo-controlled, phase II clinical trial

INTRODUCTION

Inflammation plays a critical role in the pathogenesis of atherosclerosis, the leading cause of ischaemic heart disease (IHD). Studies in preclinical models have demonstrated that an increase in regulatory T cells (Tregs), which have a potent immune modulatory action, led to a regression of atherosclerosis. The Low-dose InterLeukin 2 (IL-2) in patients with stable ischaemic heart disease and Acute Coronary Syndromes (LILACS) study, established the safety of low-dose IL-2 and its biological efficacy in IHD. The IVORY trial is designed to assess the effects of low-dose IL-2 on vascular inflammation in patients with acute coronary syndromes (ACS).

METHODS AND ANALYSIS

In this study, we hypothesise that low-dose IL-2 will reduce vascular inflammation in patients presenting with ACS. This is a double-blind, randomised, placebo-controlled, phase II clinical trial. Patients will be recruited across two centres, a district general hospital and a tertiary cardiac centre in Cambridge, UK. Sixty patients with ACS (unstable angina, non-ST elevation myocardial infarction or ST elevation myocardial infarction) with high-sensitivity C reactive protein (hsCRP) levels >2 mg/L will be randomised to receive either 1.5×10⁶ IU of low-dose IL-2 or placebo (1:1). Dosing will commence within 14 days of admission. Dosing will comprise of an induction and a maintenance phase. 2-Deoxy-2-[fluorine-18] fluoro-D-glucose (¹⁸F-FDG) positron emission tomography/CT (PET/CT) scans will be performed before and after dosing. The primary endpoint is the change in mean maximum target to background ratios (TBR_max) in the index vessel between baseline and follow-up scans. Changes in circulating T-cell subsets will be measured as secondary endpoints of the study. The safety and tolerability of extended dosing with low-dose IL-2 in patients with ACS will be evaluated throughout the study.

ETHICS AND DISSEMINATION

The Health Research Authority and Health and Care Research Wales, UK (19/YH/0171), approved the study. Written informed consent is required to participate in the trial. The results will be reported through peer-reviewed journals and conference presentations.

TRIAL REGISTRATION NUMBER

NCT04241601.

Regulatory T-Cell Response to Low-Dose Interleukin-2 in Ischemic Heart Disease

Regulatory T-Cell Response to Low-Dose Interleukin-2 in Ischemic Heart Disease This phase 1b/2a, randomized, double-blind, placebo-controlled, dose-escalation trial tested low-dose subcutaneous aldesleukin (recombinant IL-2) in patients with ischemic heart disease. Low-dose IL-2 expanded Tregs, without adverse events of major concern. Single-cell RNA-sequencing of circulating immune cells was used to provide mechanistic assessment of the treatment's effects.

Investigating the Lowest Threshold of Vascular Benefits from LDL Cholesterol Lowering with a PCSK9 mAb Inhibitor (Alirocumab) in Patients with Stable Cardiovascular Disease (INTENSITY-HIGH): protocol and study rationale for a randomised, open label, parallel group, mechanistic study

INTRODUCTION

Elevated low-density lipoprotein cholesterol (LDL-C) is a strong independent risk predictor of cardiovascular (CV) events, while interventions to reduce it remain the only evidence-based approach to reduce CV morbidity and mortality. Secondary prevention statin trials in combination with ezetimibe and/or proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors showed that there is no 'J shaped curve' in LDL-C levels with regard to CV outcomes. The lowest threshold beyond which reduction of LDL-C confers no further CV benefits has not been identified.The INTENSITY-HIGH study seeks to explore physiological mechanisms mediating CV benefits of LDL-C lowering by PCSK9 inhibition in patients with established cardiovascular disease (CVD). The study examines the changes in measures of endothelial function and vascular inflammation imaging following intervention with PCSK9 and against standard of care.

METHODS AND ANALYSIS

This is a single-centre, randomised, open label, parallel group, mechanistic physiological study. It will include approximately 60 subjects with established CVD, with LDL-C of <4.1 mmol/L on high-intensity statins. All eligible participants will undergo 18-fluorodeoxyglucose positron emission tomography/CT (FDG-PET/CT) scanning of the aorta and carotid arteries, as well as baseline endothelial function assessment. Subsequently, they will be randomised on a 1:1 basis to either alirocumab 150 mg or ezetimibe 10 mg/day. Repeat FDG-PET/CT scan and vascular assessments will be undertaken after 8 weeks of treatment. Any changes in these parameters will be correlated with changes in lipid levels and systemic inflammation biomarkers.

ETHICS AND DISSEMINATION

The study received a favourable opinion from the Wales Research Ethics Committee 4, was registered on clinicaltrials.gov and conformed to International Conference for Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use Good Clinical Practice. The results of this study will be reported through peer-reviewed journals and conference presentations.

TRIAL REGISTRATION NUMBER

NCT03355027.

Low dose interleukin-2 in patients with stable ischaemic heart disease and acute coronary syndrome (LILACS)

Background

Regulatory T lymphocytes (Tregs) are critical for immune homeostasis. Pre-clinical models have demonstrated that Tregs can modulate post-ischaemic immune responses and promote myocardial healing. Patients with ischaemic heart disease (IHD) display reduced anti-inflammatory Tregs and increased pro-inflammatory effector T cells (Teffs). Low-dose interleukin-2 (ld-IL2) has been shown to increase Tregs in patients with autoimmune diseases but is currently contraindicated in patients with IHD.

Purpose

To assess the safety and pharmacodynamic effect of ld-IL-2 in patients with IHD.

Methods

LILACS was a prospective, randomised, double-blind, placebo-controlled, dose-escalation, Phase I/II clinical trial, which tested ld-IL-2 (aldesleukin) given once daily subcutaneously, for five consecutive days. In Part A, 25 patients with stable IHD were randomised (drug:placebo ratio of 3:2) in 5 dose groups (0.3, 0.6, 1.2, 2.4 and 3x106 IU/day); whilst in Part B, 16 patients with non-ST elevation myocardial infarction (NSTEMI) were randomised (drug:placebo ratio of 6:2) in two dose groups (1.5 and 2.5x106 IU/day). Follow up was performed the day after dosing and again 7 days later. Doses were determined after blinded review. An independent committee reviewed unblinded data prior to commencing Part B. The primary endpoint was safety in parts A and B. Additionally in Part B, a co-primary endpoint was to calculate the dose required to increase Tregs by 75%. [NCT03113773]

Results

Ld-IL2 was well tolerated for all dose groups with the commonest adverse events being mild injection site reactions. Two serious adverse events, not considered to be drug related, occurred in Part B – one prior to dosing and resulting in withdrawal. The other was a recurrent NSTEMI after dosing ended in a patient with severe triple vessel coronary artery disease awaiting urgent bypass surgery. In Part A, Tregs increased with dose escalation whilst no Teff increases were noted (Figure 1A). In Part B, patients treated with 1.5 and 2.5x106 IU/day doses had a median increase in Tregs of 80.5% (CI 36.2–124.7%, p=0.003) and 108.3% (CI 55.3–161.3%, p=0.002) respectively (Figure 1B). A linear regression model estimated an increase of 43.3% (CI 23.6–63.0%, p=0.0003) per unit dose. The estimated dose to achieve a 75% increase in Tregs was 1.46x106 IU/day (CI 1.06–1.87). No increase in Teffs cells were seen however, a dose-dependent decrease was measured in B cells, whilst NK cells and eosinophils increased at the top 2.5 and 3x106 IU/day dose. A panel of 29 cytokines and chemokines showed a dose-dependent type 1 and 2 cytokine response. Single-cell RNA sequencing was performed on immune cells before and after dosing.

Conclusions

Ld-IL2 was safe and well-tolerated. An induction dose of 1.5x106 IU per day for 5 days provided an effective expansion of Tregs without increasing Teffs. This work provides important data for the future therapeutic use of ld-IL-2 which is ongoing.

Funding Acknowledgement

Type of funding source: Public Institution(s). Main funding source(s): Medical Research Council, British Heart Foundation Cambridge Centre of Excellence

Low-dose interleukin-2 in patients with stable ischaemic heart disease and acute coronary syndromes (LILACS): protocol and study rationale for a randomised, double-blind, placebo-controlled, phase I/II clinical trial

INTRODUCTION

Inflammation and dysregulated immune responses play a crucial role in atherosclerosis, underlying ischaemic heart disease (IHD) and acute coronary syndromes (ACSs). Immune responses are also major determinants of the postischaemic injury in myocardial infarction. Regulatory T cells (CD4⁺CD25⁺FOXP3⁺; Treg) induce immune tolerance and preserve immune homeostasis. Recent in vivo studies suggested that low-dose interleukin-2 (IL-2) can increase Treg cell numbers. Aldesleukin is a human recombinant form of IL-2 that has been used therapeutically in several autoimmune diseases. However, its safety and efficacy is unknown in the setting of coronary artery disease.

METHOD AND ANALYSIS

Low-dose interleukin-2 in patients with stable ischaemic heart disease and acute coronary syndromes is a single-centre, first-in-class, dose-escalation, two-part clinical trial. Patients with stable IHD (part A) and ACS (part B) will be randomised to receive either IL-2 (aldesleukin; dose range 0.3-3×10⁶ IU) or placebo once daily, given subcutaneously, for five consecutive days. Part A will have five dose levels with five patients in each group. Group 1 will receive a dose of 0.3×10⁶ IU, while the dose for the remaining four groups will be determined on completion of the preceding group. Part B will have four dose levels with eight patients in each group. The dose of the first group will be based on part A. Doses for each of the subsequent three groups will similarly be determined after completion of the previous group. The primary endpoint is safety and tolerability of aldesleukin and to determine the dose that increases mean circulating Treg levels by at least 75%.

ETHICS AND DISSEMINATION

The study received a favourable opinion by the Greater Manchester Central Research Ethics Committee, UK (17/NW/0012). The results of this study will be reported through peer-reviewed journals, conference presentations and an internal organisational report.

TRIAL REGISTRATION NUMBER

NCT03113773; Pre-results.