How to Accurately Establish Pharmacokinetics/Pharmacodynamics of Long-Acting Insulins in Humans: Relevance to Biosimilar Insulins

How to improve the quality of euglycemic glucose clamp tests in long-acting insulin studies

BACKGROUND

The euglycemic clamp test stands as the best method for assessing the pharmacokinetic and pharmacodynamic properties of long-acting insulin. However, despite its widespread use, there remains a notable absence of an established gold standard for evaluating the test's quality. Existing recommendations from regulatory agencies lack specific threshold values, particularly concerning long-acting insulin. This study aimed to determine the evaluation criteria for assessing the quality of the long-acting insulin euglycemic glucose clamp test and to improve the overall quality of this testing method.

METHODS

Fifty-three healthy volunteers were administered a single dose of insulin degludec (0.4 IU/kg) and underwent a 24-h euglycemic clamp test. Blood samples were collected to evaluate the pharmacokinetics and pharmacodynamics of insulin degludec. Volunteers were separated into group A (coefficient of variation in blood glucose [CVBG] ≤ 3.5%) and group B (CVBG > 3.5%). The quality difference of the clamp test between the groups was assessed using various quality control indices. Volunteers were also categorized into group C (C-peptide reduction rate < 50%) and group D (C-peptide reduction rate ≥ 50%). The clamp test quality, pharmacokinetics, and pharmacodynamics of groups C and D were compared.

RESULTS

According to CVBG, group A had a mean CVBG of 2.95%, group B had a mean CVBG of 4.15%, and group A had a significantly lower CVBG than group B (p < 0.001). CVBG was positively correlated with other quality control indicators, such as the percentage of glucose excursion from the target range (GEFTR), duration of GEFTR, and area under the curve (AUC) of GEFTR. According to the reduction of C-peptide levels: group D had significantly higher C-peptide reduction than group C (p < 0.001). Groups C and D had CVBG < 3.5%. The quality of groups C and groups D was evaluated by the quality control indicators of the clamp test. Only the AUC of GEFTR was statistically different between Groups C and D (p = 0.043, < 0.05), and there was no statistical difference in other indicators between the two groups.

CONCLUSIONS

CVBG could be used as a standard for evaluating the quality of long-acting insulin euglycemic glucose clamp test, and the test quality was superior with a CVBG ≤ 3.5%. A C-peptide reduction ratio ≥ 50% indicated sufficient endogenous insulin inhibition; however, when the glucose fluctuation is small (CVBG is maintained at a low level) during the clamp test, even if the clamp test quality is slightly different, it is not sufficient to interfere with endogenous insulin secretion.

Pharmacokinetic and pharmacodynamic bioequivalence of Gan & Lee insulin analogues aspart (rapilin®), lispro (prandilin®) and glargine (basalin®) with EU- und US-sourced reference insulins

AIM

For the successful approval and clinical prescription of insulin biosimilars, it is essential to show pharmacokinetic (PK) and pharmacodynamic (PD) bioequivalence to the respective reference products sourced from the European Union and the United States.

METHODS

Three phase 1, randomized, double-blind, three-period crossover trials compared single doses of the proposed biosimilar insulin analogues aspart (GL-Asp, n = 36), lispro (GL-Lis, n = 38) and glargine (GL-Gla, n = 113), all manufactured by Gan & Lee pharmaceuticals, to the respective EU- and US-reference products in healthy male participants (GL-Asp and GL-Lis) or people with type 1 diabetes (GL-Gla). Study participants received 0.2 U/kg (aspart and lispro) or 0.5 U/kg (glargine) of each treatment under automated euglycaemic clamp conditions. The clamp duration was 12 h (aspart and lispro) or 30 h (glargine). Primary PK endpoints were the total area under the PK curves (AUCins.total ) and maximum insulin concentrations (Cins.max ). Primary PD endpoints were the total area under the glucose infusion rate curve (AUCGIR.total ) and maximum glucose infusion rate (GIRmax ).

RESULTS

Bioequivalence to both EU- and US-reference products were shown for all three GL insulins. Least squares mean ratios for the primary PK/PD endpoints were close to 100%, and both 90% and 95% confidence intervals were within 80%-125% in all three studies. There were no noticeable differences in the safety profiles between test and reference insulins, and no serious adverse events were reported for the GL insulins.

CONCLUSION

GL-Asp, GL-Lis and GL-Gla are bioequivalent to their EU- and US-reference products.

How to Achieve Sufficient Endogenous Insulin Suppression in Euglycemic Clamps Assessing the Pharmacokinetics and Pharmacodynamics of Long-Acting Insulin Preparations Employing Healthy Volunteers

The therapeutic effect of basal insulin analogs will be sustained at a rather low insulin level. When employing healthy volunteers to assess the pharmacokinetics (PK) and pharmacodynamics (PD) of long-acting insulin preparations by euglycemic clamp techniques, endogenous insulin cannot be ignored and sufficient endogenous insulin inhibition is crucial for the PD and/or PK assessment. This study aimed to explore a way to sufficiently inhibit endogenous insulin secretion. Healthy Chinese male and female volunteers were enrolled. After a subcutaneous injection of insulin glargine (IGlar) (LY2963016 or Lantus) (0.5 IU/kg), they underwent a manual euglycemic clamp for up to 24 h where the target blood glucose (BG) was set as 0.28 mmol/L below the individual’s baseline. Blood samples were collected for analysis of PK/PD and C-peptide. The subjects fell into two groups according to the reduction extent of postdose C-peptide from baseline. After matching for the dosage proportion of Lantus, there were 52 subjects in group A (C-peptide reduction&lt;50%) and 26 in group B (C-peptide reduction≥50%), respectively. No significant difference was detected in age, body mass index, the proportion of Latus treatment and female participants. A lower basal BG was observed in group B compared to group A (4.35 ± 0.26 vs. 4.59 ± 0.22 mmol/L, p &lt; 0.05). The clamp studies were all conducted with high quality (where BG was consistently maintained around the target and exhibited a low variety). The binary logistic regression analysis indicated low basal BG as an independent factor for the success of sufficient endogenous insulin suppression. In conclusion, setting a lower sub-baseline target BG (e.g., 10% instead of 5% below baseline) might be an approach to help achieve sufficient endogenous insulin suppression in euglycemic clamps with higher basal BG levels (e.g., beyond 4.60 mmol/L).

Effects of Unsuppressed Endogenous Insulin on Pharmacokinetics and/or Pharmacodynamics of Study Insulin in the Healthy: A Retrospective Study

C‐peptide, a marker of endogenous insulin, should be consistently inhibited during euglycemic clamping, while an elevated postdosing C‐peptide (CP_postdosing) is not an occasional phenomenon. This was a retrospective study that included 33 men who underwent a manual euglycemic clamp with a subcutaneous injection of insulin aspart (IAsp) aiming to describe the effects of insufficient suppression of endogenous insulin on estimates of the pharmacokinetics and pharmacodynamics of injected insulin. The time profiles of whole blood glucose, human insulin, glucose infusion rate (GIR), and C‐peptide were recorded. The subjects were divided into 2 groups at a ratio of 2:1: group A ([CP_postdosing]_max>baseline CP [CP_baseline]), group B ([CP_postdosing]_max ≤ CP_baseline). The endogenous insulin was approximately equal to the measured value of human insulin or calculated from the C‐peptide. The basal glucose, CP_baseline, basal human insulin, homeostatic model assessment of insulin resistance, IAsp dose, and demographic statistics were all comparable between the 2 groups except the “clamped” glucose. The average clamped glucose was 99.7% (group A) and 94.9% (group B) of baseline. After correction for clamped glucose, GIR area under the concentration‐time curve from time 0 to 8 hours was higher in group A (P < .05) under comparable IAsp exposure. Endogenous insulin area under the concentration‐time curve from time 0 to 8 hours calculated from C‐peptide was different from that measured from human insulin in group A (P < .05), whereas no statistical difference between these measures was observed in group B. Hence, blood glucose should be controlled below the baseline to ensure the inhibition of endogenous insulin. Unsuppressed endogenous insulin may contribute to observed GIR, and the endogenous insulin–corrected pharmacokinetics estimated by C‐peptide may be inaccurate with insufficient endogenous insulin suppression.

Reduction in C-Peptide Levels and Influence on Pharmacokinetics and Pharmacodynamics of Insulin Preparations: How to Conduct a High-Quality Euglycemic Clamp Study

Objective: The aim of the study was to investigate the different extent of inhibition of endogenous insulin secretion by the reduction of C-peptide levels in an euglycemic clamp study and its effects on the evaluation of pharmacokinetics, pharmacodynamics of insulin preparations, and quality of clamp study to determine the best reduction range of C-peptide levels. Methods: Healthy Chinese male volunteers were enrolled and underwent a single-dose euglycemic clamp test. Participants were subcutaneously injected with long-acting insulin glargine (0.4 IU/kg). Blood samples were collected pretest and up to 24 h post-test to assess pharmacokinetics (PK), pharmacodynamics (PD), and C-peptide levels. Results: We divided the 39 volunteers enrolled in the study into three groups according to the reduction of C-peptide levels: group A (ratio of C-peptide reduction <30%, n = 13), group B (ratio of C-peptide reduction between ≥ 30% and <50%, n = 15), and group C (ratio of C-peptide reduction ≥50%, n = 11); there were significant differences in the three groups (p = 0.000). The upper and lower limits of blood glucose oscillation in group C was statistically lower than the other groups, the range of oscillating glucose levels in group C was -17.0 ± 6.6% to -1.1 ± 6.7%. The AUC_0-24 h in groups A, B, and C were 9.7 ± 2.2, 11.0 ± 2.9, and 11.9 ± 2.1 ng/ml × min, respectively, which indicated an increasing trend in the three groups (P _trend = 0.041). For quality assessment, the average glucose (p = 0.000) and MEFTG (p = 0.001) levels in three groups were significantly different. Conclusion: The different extent of inhibition of endogenous insulin will influence the PK/PD of insulin preparations and the quality of the euglycemic clamp. Furthermore, the ratio of C-peptide reduction should be above 50% to free from the interference of endogenous insulin, and the range of blood glucose levels should be consistently maintained at -10% to 0 in the euglycemic clamp.

Pharmacokinetic and Pharmacodynamic Head-to-Head Comparison of Clinical, Equivalent Doses of Insulin Glargine 300 units · mL-1 and Insulin Degludec 100 units · mL-1 in Type 1 Diabetes

OBJECTIVE

To prove equivalence of individual, clinically titrated basal insulin doses of glargine 300 units ⋅ mL^-1 (Gla-300) and degludec 100 units ⋅ mL^-1 (Deg-100) under steady state conditions in a single-blind, randomized, crossover study, on the glucose pharmacodynamics (PD) in people with type 1 diabetes (T1D).

RESEARCH DESIGN AND METHODS

Subjects with T1D (N = 22, 11 men, age 44.3 ± 12.4 years, disease duration 25.5 ± 11.7 years, A1C 7.07 ± 0.63% [53.7 ± 6.9 mmol ⋅ mL^-1], BMI 22.5 ± 2.7 kg · m^-2), naïve to Gla-300 and Deg-100, underwent 24-h euglycemic clamps with individual clinical doses of Gla-300 (0.34 ± 0.08 units ⋅ kg^-1) and Deg-100 (0.26 ± 0.06 units ⋅ kg^-1), dosing at 2000 h, after 3 months of optimal titration of basal (and bolus) insulin.

RESULTS

At the end of 3 months, Gla-300 and Deg-100 reduced slightly and, similarly, A1C versus baseline. Clamp average plasma glucose (0-24 h) was euglycemic with both insulins. The area under curve of glucose infused (AUC-GIR_{[0-24 h]}) was equivalent for the two insulins (ratio 1.04, 90% CI 0.91-1.18). Suppression of endogenous glucose production, free fatty acids, glycerol, and β-hydroxybutyrate was 9%, 14%, 14%, and 18% greater, respectively, with Gla-300 compared with Deg-100 during the first 12 h, while glucagon suppression was no different. Relative within-day PD variability was 23% lower with Gla-300 versus Deg-100 (ratio 0.77, 90% CI 0.63-0.92).

CONCLUSIONS

In T1D, individualized, clinically titrated doses of Gla-300 and Deg-100 at steady state result in similar glycemic control and PD equivalence during euglycemic clamps. Clinical doses of Gla-300 compared with Deg-100 are higher and associated with quite similar even 24-h distribution of PD and antilipolytic effects.

Equipotency of insulin glargine 300 and 100 U/mL with intravenous dosing but differential bioavailability with subcutaneous dosing in dogs

AIMS

Insulin glargine 300 U/mL (Gla-300) contains the same units versus glargine 100 U/mL (Gla-100) in three-fold lower volume, and higher subcutaneous (SC) doses are required in people with diabetes. To investigate blood glucose (BG) lowering potency, Gla-300 and Gla-100 were compared after intravenous (IV, for 4 h) and SC (for 24 h) injection in healthy Beagle dogs.

MATERIALS AND METHODS

The dose of 0.15 U/kg Gla-300 and Gla-100 was injected IV in 12 dogs. BG, C-peptide, glucagon and the active metabolite 21A-Gly-human insulin (M1; liquid chromatography-tandem mass spectrometry method) were measured. Twelve other dogs were studied after SC injection of 0.3 U/kg Gla-300 and Gla-100.

RESULTS

After IV injection, Gla-300 and Gla-100 were equally potent [BG_AUC_{0-4 h} ratio 1.01 (95% confidence interval, 0.94; 1.09)]. After SC injection, BG decreased slower and less with Gla-300. Similar metabolism of Gla-300 and Gla-100 to M1 occurred with IV dosing [M1_AUC_{0-1 h} ratio 0.99 (95% confidence interval, 0.82; 1.22)], but with SC dosing M1_C_max and AUC_0-24h were 44% and 17% lower; mean residency time and bioavailability were 32% longer and 50% lower, with Gla-300.

CONCLUSIONS

IV Gla-300 and Gla-100 have the equivalent of BG-lowering potency and M1 metabolism. SC Gla-300 has lower M1 bioavailability with a reduced BG-lowering effect and need for greater doses versus Gla-100.

Pharmacokinetic and pharmacodynamic bioequivalence of proposed biosimilar MYL-1501D with US and European insulin glargine formulations in patients with type 1 diabetes mellitus

AIMS

To report phase 1 bioequivalence results comparing MYL-1501D, US reference insulin glargine (US IG), and European reference insulin glargine (EU IG).

MATERIALS AND METHODS

The double-blind, randomized, three-way crossover study compared the pharmacokinetic (PK) and pharmacodynamic (PD) characteristics of MYL-1501D, US IG and EU IG. In total, 114 patients with type 1 diabetes (T1DM) received 0.4 U/kg of each study treatment under automated euglycaemic clamp conditions. Insulin metabolite M1 concentrations, insulin glargine (IG) and glucose infusion rates (GIRs) were assessed over 30 hours. Primary PK endpoints were area under the serum IG concentration-time curve from 0 to 30 hours (AUCins.0-30h ) and maximum serum IG concentration (Cins.max ). Primary PD endpoints were area under the GIR-time curve from 0 to 30 hours (AUCGIR0-30h ) and maximum GIR (GIRmax ).

RESULTS

Bioequivalence among MYL-1501D, US IG and EU IG was demonstrated for the primary PK and PD endpoints. Least squares mean ratios were close to 1, and 90% confidence intervals were within 0.80 to 1.25. The PD GIR-time profiles were nearly superimposable. There were no noticeable differences in the safety profiles of the three treatments, and no serious adverse events were reported.

CONCLUSIONS

Equivalence with regard to PK and PD characteristics was shown among MYL-1501D, US IG and EU IG in patients with T1DM, and each treatment was well tolerated and safe.

Pharmacokinetics, Pharmacodynamics, and Modulation of Hepatic Glucose Production With Insulin Glargine U300 and Glargine U100 at Steady State With Individualized Clinical Doses in Type 1 Diabetes

OBJECTIVE

This study characterized the pharmacokinetics (PK), pharmacodynamics (PD), and endogenous (hepatic) glucose production (EGP) of clinical doses of glargine U300 (Gla-300) and glargine U100 (Gla-100) under steady-state (SS) conditions in type 1 diabetes mellitus (T1DM).

RESEARCH DESIGN AND METHODS

T1DM subjects (N = 18, age 40 ± 12 years, T1DM duration 26 ± 12 years, BMI 23.4 ± 2 kg/m², A1C 7.19 ± 0.52% [55 ± 5.7 mmol · mol-1^-1]) were studied after 3 months of Gla-300 or Gla-100 (evening dosing) titrated to fasting euglycemia (random, crossover) with the euglycemic clamp using individualized doses (Gla-300 0.35 ± 0.08, Gla-100 0.28 ± 0.07 units · kg^-1).

RESULTS

Plasma free insulin concentrations (free immunoreactive insulin area under the curve) were equivalent over 24 h with Gla-300 versus Gla-100 (point estimate 1.11 [90% CI 1.03; 1.20]) but were reduced in the first 6 h (0.91 [90% CI 0.86; 0.97]) and higher in the last 12 h postdosing (1.38 [90% CI 1.21; 1.56]). Gla-300 and Gla-100 both maintained 24 h euglycemia (0.99 [90% CI 0.98; 1.0]). The glucose infusion rate was equivalent over 24 h (1.03 [90% CI 0.88; 1.21]) but was lower in first (0.77 [90% CI 0.62; 0.95]) and higher (1.53 [90% CI 1.23; 1.92]) in the second 12 h with Gla-300 versus Gla-100. EGP was less suppressed during 0-6 h but more during 18-24 h with Gla-300. PK and PD within-day variability (fluctuation) was 50% and 17% lower with Gla-300.

CONCLUSIONS

Individualized, clinical doses of Gla-300 and Gla-100 resulted in a similar euglycemic potential under SS conditions. However, Gla-300 exhibited a more stable profile, with lower variability and more physiological modulation of EGP compared with Gla-100.

Euglycaemic glucose clamp: what it can and cannot do, and how to do it

The hyperinsulinaemic-euglycaemic glucose clamp has always been regarded as the "gold standard" for the assessment of pharmacodynamic (PD) properties of insulin preparations; however, there has been controversy over a variety of methodogical details, such as study population, dosing time and the initial stabilization of blood glucose (BG) concentrations at the clamp target level, among clamp groups. As the impact of these details on PD results is unclear, the present review provides an overview of different methodological approaches for both the manual and the automated hyperinsulinaemic-euglycaemic glucose clamp. The advantages and limitations of several methodological details are discussed as well as the relevance of clamp results for the prediction of clinical outcomes. Overall, the best method strongly depends on the exact objective of the trial. If, for instance, duration of action is the primary objective, studies should be carried out in patients with type 1 diabetes to avoid any interference of endogenous insulin. This is less important for variables such as onset of action or early metabolic activity. The hyperinsulinaemic-euglycaemic glucose clamp has a high sensitivity to detect even minor differences between different insulin preparations. The practical relevance of potential differences, however, needs to be investigated in clinical studies. A major prerequisite for obtaining reliable glucose clamp results is the attainment of high clamp quality (i.e. keeping BG concentrations close to the clamp target throughout the experiments). Unfortunately, measures of clamp quality are often under-reported, as is the variability in PD profiles, although these might explain some unconfirmed extreme results obtained in a few clamp studies.