Pharmacokinetics and Glucodynamics of Ultra Rapid Lispro (URLi) versus Humalog^® (Lispro) in Patients with Type 2 Diabetes Mellitus: A Phase I Randomised, Crossover Study

This was a phase I, randomised, two-period, two-treatment, double-blind, crossover glucose clamp study in patients with T2DM (Fig. 1). The study was conducted at one site (Profil, Neuss, Germany), from 16 October, 2017 to 14 December, 2017. The protocol was approved by an independent ethics committee. The study was conducted in accordance with the Declaration of Helsinki, the International Conference on Harmonisation guidelines for Good Clinical Practice, and applicable laws and regulations. All patients provided written informed consent before participating in the study. The study was registered at www.​clinicaltrials.​gov (NCT03305822).

Male and female patients with T2DM (≥ 1-year duration) based on medical history, aged between 18 and 70 years and with a body mass index of 18.5–35.0 kg/m² were eligible. Patients had HbA1c < 9.0%, fasting C-peptide ≤ 1.0 nmol/L, without any reports of severe hypoglycaemia over a period of 6 months before study enrolment, and were receiving stable prandial insulin ± basal insulin ± a stable dose of oral antidiabetic drugs. Patients receiving a continuous SC insulin infusion, daily insulin treatment ≥ 1.2 U/kg/body weight, insulin degludec or dulaglutide were excluded.

Patients were randomised to receive a single 15-unit SC dose of the study drug (URLi or Humalog U100 formulations [Eli Lilly, Indianapolis, IN, USA]) in the first dosing period and the other study drug in the second dosing period (Fig. 1).

Each study period was separated by a wash-out period of at least 72 h. At any time in the 2 weeks before day − 1 of period 1, patients discontinued dipeptidyl peptidase-4 inhibitors, sulphonylureas and sodium-glucose co-transporter-2 inhibitors. Patients were not permitted to receive long-term systemic or inhaled glucocorticoids (> 14 consecutive days) during or within 4 weeks of commencing the study. Patients taking a stable dose of metformin were permitted to continue their medication during the study.

Before each dosing period, patients were to discontinue their basal insulin for a predefined treatment-specific wash-out period. The last injection of basal insulin was to occur no later than 72 h before dosing (insulin glargine U300), 48 h before dosing (insulin detemir or glargine U100) or 24 h before dosing (neutral protamine Hagedorn insulin, insulin mixtures or other intermediate-acting insulin). Any injection of more than 6 units of short-acting insulin was not to occur between 11 and 6 h before dosing and no injection was to occur less than 6 h before dosing.

At each dosing visit, patients underwent a 10 h, automated euglycaemic clamp procedure using the ClampArt^® device (Profil, Neuss, Germany). Procedures were performed following an overnight fast of at least 8 h. Before study drug dosing, patients were connected to the clamp device for continuous glucose monitoring and the start of the baseline run-in period. A variable intravenous infusion of either glucose (20% dextrose solution) or insulin glulisine was started to reach a target blood glucose concentration of 100 mg/dL ± 20% (5.5 ± 1.1 mmol/L) during the run-in period. Blood glucose was maintained at 100 mg/dL ± 10% (5.5 ± 0.55 mmol/L) for the last 30 min before study drug injection, without any glucose infusion or insulin glulisine infusion. If stable blood glucose was not achieved, the run-in period was prolonged or study drug dosing was postponed. Baseline was defined as the mean of blood glucose concentrations at 6, 4 and 2 min before study drug administration and the onset of insulin action was defined as when the blood glucose concentration dropped by 5 mg/dL (0.3 mmol/L) from baseline.

Once the target blood glucose level was attained and remained stable, the patient received study treatment (URLi or Humalog; time = 0). After the onset of insulin action was reached, a variable intravenous glucose infusion rate (GIR) was initiated to maintain blood glucose at the target concentration (100 mg/dL; 5.5 mmol/L). The GIR necessary to maintain blood glucose at the target level was recorded every minute throughout the glucose clamp procedure. Blood samples were measured (SuperGL glucose analyser, Dr Müller; Hitado, Möhnesee, Germany) at least every 30 min during the clamp procedure to validate clamp glucose sensor measurements. The clamp procedure was continued for approximately 10 h postdose or until after blood glucose concentrations increased to > 200 mg/dL (11.1 mmol/L) without any glucose being administered for at least 30 min, whichever was earlier.

Serum free insulin lispro was analysed using a validated enzyme-linked immunosorbent assay specific to insulin lispro without cross-reactivity to endogenous insulin. Samples were collected at time 0, every 5 min for the first hour, at 70, 90, 120, 150 and 180 min, and hourly thereafter up to 10 h postdose. The lower limit of quantification (LLOQ) was 8.6 pmol/L. Inter-assay accuracy (% relative error) and inter-assay precision (% relative standard deviation) during validation were ≤ 16%.

Serum blood samples were collected at time 0, 30 min, and hourly after the first hour until completion of the clamp procedure for C-peptide and were analysed using a validated enzyme-linked immunosorbent assay. The LLOQ was 0.07 ng/mL. The inter-assay precision (% relative standard deviation) was < 8% and there was no cross-reactivity to insulin or proinsulin.

Free serum insulin lispro pharmacokinetic parameters were calculated by non-compartmental methods using Phoenix^® version 6.4 and S PLUS^® version 8.2. Early exposure endpoints included: time to early half-maximal drug concentration (early 50% t_max); area under the concentration–time curve (AUC) from 0 to 15 min (AUC_0-15min), to 30 min (AUC_0-30min), and onset of appearance, defined as the time that serum insulin lispro reached the LLOQ. The determination of onset of appearance used a linear interpolation between the time of dosing (0 concentration) and the time of the first quantifiable insulin lispro concentration and was only conducted in those patients where the predose sample was below the LLOQ. Late exposure endpoints included: time to late half-maximal drug concentration (late 50% t_max); AUC from time 3 to 10 h (AUC_3-10h) and duration of exposure, defined as the time from dosing until serum insulin lispro reached the LLOQ. Overall exposure endpoints were AUC from time 0 to infinity (AUC_0-∞) and maximum observed drug concentration (C_max).

Glucodynamics were derived from the glucose clamp procedure, with GIR over time used as a measure of insulin effect. A locally weighted scatterplot smoothing (LOESS) function with a span of 0.1 was applied to all individual GIR-versus-time profiles in each treatment group and/or period. The fitted data for each patient were used to calculate the GD parameters, except for the time to onset of insulin action (T_onset), which was based on the raw GIR data. Glucodynamic analyses were conducted using Phoenix^® version 6.4 or higher and S PLUS^® version 8.2. Early insulin action endpoints were: T_onset, defined as the time when blood glucose drops by 0.3 mmol/L (5 mg/dL) from baseline, time to half-maximal GIR before time to maximum GIR (early 50% tR_max), and the total amount of glucose infused over the first 30 min (G_{tot,0–30min}) and the first 1 h (G_tot,0–1h). Late insulin action endpoints were: time to half-maximal GIR after time to maximum GIR (late 50% tR_max), total amount of glucose infused from 4 h to the end of the clamp (G_tot,4h–End), and duration of insulin action, defined as the time from T_onset to the first time when the GIR was less than the average LOESS GIR, which was calculated from all patients from 9 to 10 h after injection and remained below this value for at least 30 min. Total insulin action endpoints were maximum GIR (R_max) and total amount of glucose infused over the duration of the clamp G_tot). Safety assessments included adverse events, injection-site assessments (immediately after dosing, and at 20 and 60 min), clinical laboratory assessments (predose period 1 and as deemed necessary), and vital signs and electrocardiograms (predose and end of the clamp procedure).

At least 34 completers provided approximately 95% power to demonstrate a 40% increase in insulin lispro AUC_0-30min between URLi and Humalog. Pharmacokinetic (PK) and GD analyses included all patients who completed both clamp procedures and had evaluable PK and GD data for both study periods. Log-transformed PK and GD parameters were evaluated using linear mixed models with treatment, sequence, and period as fixed effects and patient as a random effect; the treatment ratios of geometric least squares (LS) means were estimated from the model. The same model without log transformation was used to analyse the PK and GD time parameters. Least squares means, treatment differences in LS means and the corresponding 95% confidence intervals for the treatment differences were estimated from the model. For the GD analyses, the p value for the difference between LS means or the ratio of geometric LS means was used to determine statistical significance. The 95% confidence interval for the treatment ratio was estimated using Fieller’s theorem [14]. Statistical analyses were conducted using SAS^® version 9.4, SAS Institute, Cary, NC, USA at a 5% significance level.

A total of 38 patients, 35 male and three female, were enrolled, randomised and completed the study (Table 1). The mean age was 60.0 years, mean duration of diabetes was 17.4 years and mean HbA1c was 7.4%.

The mean serum C-peptide profiles during the euglycaemic clamp procedure were similar following a 15-unit SC dose of URLi and Humalog (Fig. 4). Upon injection of the study drugs, the C-peptide concentrations reduced from baseline indicating a suppression by the exogenous insulins. The reduction in the C-peptide concentration in the first 2 h after the start of the clamp procedure was greater with URLi compared with Humalog, which aligns with the faster insulin action observed with LY900014. There was a rise above baseline in the C-peptide concentration with both treatments at 6 h after the start of the clamp procedure, which corresponds to the time when the insulin lispro concentration approached the LLOQ.

URLi and Humalog were well tolerated and no unexpected safety signals were identified in the current study (Table 4). The frequency of treatment-emergent adverse events (TEAEs) following administration of Humalog or URLi was similar (eight vs. six events, respectively), with a total of 14 TEAEs in 11 patients (six vs. six). Most TEAEs were mild or moderate (seven and six, respectively) in severity and no patients discontinued because of TEAEs. One patient had a serious TEAE of coronary artery stenosis 13 days after Humalog administration in period 2, determined to be unrelated to the study drug. This patient had resumed their normal/pre-study insulin therapy when this serious TEAE occurred.

The most common TEAEs that occurred in two or more patients with either treatment were headache and vessel puncture-site thrombosis. There was one report of very slight (barely perceptible) injection-site erythema following an URLi injection. There were no reports of hypoglycaemia during the period of clamp assessment. No clinically relevant changes in vital signs, electrocardiograms or laboratory values occurred during the study.