Anti-insulin antibodies in insulin immunometric assays: a still possible pitfall

Fast-Acting Insulin Aspart: A Review of its Pharmacokinetic and Pharmacodynamic Properties and the Clinical Consequences

Fast-acting insulin aspart (faster aspart) is insulin aspart (IAsp) with two added excipients, l-arginine and niacinamide, to ensure formulation stability with accelerated initial absorption after subcutaneous administration compared with previously developed rapid-acting insulins. The pharmacokinetic/pharmacodynamic properties of faster aspart have been characterised in clinical pharmacology trials with comparable overall methodology. In subjects with type 1 (T1D) or type 2 (T2D) diabetes, the serum IAsp concentration–time and glucose-lowering effect profiles are left-shifted for faster aspart compared with IAsp. In addition, faster aspart provides earlier onset, doubling of initial exposure, and an up to 2.5-fold increase in initial glucose-lowering effect within 30 min of subcutaneous injection, as well as earlier offset of exposure and effect. Similar results have been shown using continuous subcutaneous insulin infusion (CSII). The improved pharmacological properties of faster aspart versus IAsp are consistent across populations, i.e. in the elderly, children, adolescents and the Japanese. Thus, the faster aspart pharmacological characteristics more closely resemble the mealtime insulin secretion in healthy individuals, giving faster aspart the potential to further improve postprandial glucose control in subjects with diabetes. Indeed, change from baseline in 1-h postprandial glucose increment is in favour of faster aspart versus IAsp when used as basal-bolus or CSII treatment in phase III trials in subjects with T1D or T2D. This review summarises the currently published results from clinical pharmacology trials with faster aspart and discusses the potential clinical benefits of faster aspart compared with previous rapid-acting insulin products.

The association between anti-insulin aspart antibodies and the pharmacokinetic and pharmacodynamic characteristics of fast-acting insulin aspart in children and adolescents with type 1 diabetes

BACKGROUND

Fast-acting insulin aspart (faster aspart) is a novel formulation of insulin aspart (IAsp) ensuring ultrafast absorption and effect.

AIM

To compare the pharmacokinetics between faster aspart and IAsp, based on free or total IAsp measurement, and investigate the association between anti-IAsp antibodies and faster aspart and IAsp pharmacological properties in children and adolescents with type 1 diabetes (T1D).

METHODS

In a randomized, two-period crossover trial, 12 children, 16 adolescents, and 15 adults (6-11, 12-17, and 18-64 years) received 0.2 U/kg double-blindsingle-dose subcutaneous faster aspart or IAsp followed by a standardized liquid meal test.

RESULTS

Across age groups, the pharmacokinetic profile was left-shifted including greater early exposure for faster aspart vs IAsp irrespective of free or total IAsp assay. Onset of appearance occurred 2.4 to 5.0 minutes (free) or 1.8 to 3.0 minutes (total) earlier for faster aspart vs IAsp (P < .05). Treatment ratios (faster aspart/IAsp) for 0 to 30 minutes IAsp exposure were 1.60 to 2.11 and 1.62 to 1.96, respectively (children, free: P = .062; otherwise P < .05). The ratio of free/total IAsp for overall exposure (AUC_IAsp,0-t ) was negatively associated with anti-IAsp antibody level across age. Pooling with a previous similar trial showed no clear association between anti-IAsp antibodies and meal test 1- or 2-hour postprandial glucose increment independent of age and insulin treatment (R² ≤ .070; P ≥ .17).

CONCLUSIONS

In children and adolescents with T1D, faster aspart provides ultrafast pharmacokinetics irrespective of free or total IAsp assay. Elevated anti-IAsp antibodies are associated with higher total IAsp concentration, but do not impact faster aspart and IAsp glucose-lowering effect.

Clinical Pharmacology of Fast-Acting Insulin Aspart Versus Insulin Aspart Measured as Free or Total Insulin Aspart and the Relation to Anti-Insulin Aspart Antibody Levels in Subjects with Type 1 Diabetes Mellitus

Background

Fast-acting insulin aspart (faster aspart) is an ultra-fast-acting formulation of insulin aspart (IAsp). This post hoc analysis investigated the pharmacokinetics of faster aspart versus IAsp, measured as free or total IAsp, and the relationship between anti-IAsp antibodies and the pharmacokinetics/pharmacodynamics of faster aspart and IAsp.

Methods

Free and total IAsp concentrations and anti-IAsp antibodies were determined in adults with type 1 diabetes mellitus receiving subcutaneous faster aspart and/or IAsp in four single-dose clinical pharmacology trials (n = 175) and a 26-week phase IIIa trial (n = 1040). Pharmacodynamics were assessed by euglycaemic clamp or meal test, respectively.

Results

The pharmacokinetic profile was left-shifted and early exposure was greater with faster aspart versus IAsp independent of free or total IAsp assay. The faster aspart-IAsp difference in the time to 50% of maximum IAsp concentration in the early part of the pharmacokinetic profile (t_{Early 50 % Cmax}) [95% confidence interval (CI)] was − 8.8 [− 10.0 to − 7.5] and − 7.6 [− 8.8 to − 6.4] min for free and total IAsp, respectively. The faster aspart/IAsp ratio for the area under the concentration–time curve (AUC) for IAsp from time zero to 30 min (AUC_{IAsp,0–30 min}) [95% CI] was 1.88 [1.74–2.04] and 1.77 [1.64–1.90] for free and total IAsp. Higher anti-IAsp antibody levels were associated with a lower ratio of free/total IAsp for the total AUC for IAsp (AUC_IAsp,0–t). Early glucose-lowering effect (AUC for the glucose infusion rate [GIR] from time zero to 60 min [AUC_{GIR,0–60 min}]) was greater by 25–44% for faster aspart versus IAsp independent of anti-IAsp antibody levels. Total glucose-lowering effect (total AUC for GIR [AUC_GIR,0–t]) in a clamp and 1-h postprandial glucose increment in a meal test appeared essentially unaffected by anti-IAsp antibodies.

Conclusions

Faster aspart provides accelerated pharmacokinetics versus IAsp regardless if based on free or total IAsp assay. Higher anti-IAsp antibodies increase total IAsp concentrations but do not influence faster aspart nor IAsp pharmacodynamics.

ClinicalTrials.gov identifiers

NCT01618188, NCT02003677, NCT01934712, NCT02568280, NCT01831765.

Electronic supplementary material

The online version of this article (10.1007/s40262-018-0718-6) contains supplementary material, which is available to authorized users.

Insulin autoimmune syndrome in an Argentine woman taking α-lipoic acid: A case report and review of the literature

Insulin autoimmune syndrome is an unusual cause of spontaneous hypoglycaemia in non-Asian populations. In the majority of cases, this syndrome appears a few weeks after the administration of drugs containing a sulfhydryl group. A strong association between this syndrome and HLA-DR4 has been shown. Only seven cases have been described in non-Asian patients. We report the first case of insulin autoimmune syndrome in an Argentine woman taking alfa-lipoic acid. She developed hypoglycaemic symptoms approximately 1 month after starting therapy. Blood sampling collected during an episode of symptomatic hypoglycaemia showed low blood glucose level (2.39 mmol/L), high level of serum insulin (1971.55 pmol/L), inappropriately high level of C-peptide (2.36 nmol/L) and high levels of insulin antibodies (274.78 IU/mL). HLA-DNA typing identified DRB1*04:03. Due to the widespread use of alfa-lipoic acid for its antioxidant properties, clinicians should be aware that it may trigger an autoimmune hypoglycaemia in people with a genetic predisposition.

The effects of anti-insulin antibodies and cross-reactivity with human recombinant insulin analogues in the E170 insulin immunometric assay

BACKGROUND

Insulin assays are affected by varying degrees of interference from anti-insulin antibodies (IAs) and by cross-reactivity with recombinant insulin analogues. We evaluated the usefulness of the E170 insulin assay by assessing IA effects and cross-reactivity with 2 analogues.

METHODS

Sera were obtained from 59 type 2 diabetes patients receiving continuous subcutaneous insulin infusion and 18 healthy controls. Insulin levels were determined using an E170 analyzer. To investigate the effects of IAs, we performed IA radioimmunoassays, and analyzed the differences between directly measured insulin (direct insulin) and polyethylene glycol (PEG)-treated insulins (free, IA-unbound; total, IA-bound and unbound insulin). We performed in-vitro cross-reactivity tests with insulin aspart and insulin glulisine.

RESULTS

In IA-positive patients, E170 free insulin levels measured using the E170 analyzer were significantly lower than the direct insulin levels. The mean value of the direct/free insulin ratio and IA-bound insulin, which were calculated as the difference between total and free insulin, increased significantly as endogenous IA levels increased. The E170 insulin assay showed low cross-reactivities with both analogues (< 0.7%).

CONCLUSIONS

IAs interfered with E170 insulin assay, and the extent of interference correlated with the IA levels, which may be attributable to the increase in IA-bound insulin, and not to an error in the assay. The E170 insulin assay may measure only endogenous insulin since cross-reactivity is low. Our results suggest that the measurement of free insulin after PEG pre-treatment could be useful for beta cell function assessment in diabetic patients undergoing insulin therapy.

Impaired glucose tolerance and abnormal movements in patients with schizophrenia

OBJECTIVE

Diabetes mellitus has been implicated as a risk factor for tardive dyskinesia. The authors examined the association between abnormal movements and impaired glucose metabolism, which often precedes the development of overt diabetes, in patients with schizophrenia.

METHOD

Twenty-one patients with DSM-IV schizophrenia receiving neuroleptic medication were given oral glucose tolerance tests involving serial glucose and insulin levels. These values were analyzed in relationship to abnormal involuntary movement ratings.

RESULTS

Patients with impaired glucose tolerance had higher mean abnormal movement scores than those without glucose intolerance, but this difference was not statistically significant. There was, however, an association between the magnitude of the fasting insulin level and abnormal movements after the authors controlled for fasting glucose level. Additionally, the fasting glucose level predicted abnormal movements after the authors controlled for age.

CONCLUSIONS

Hyperinsulinemia and hyperglycemia associated with insulin resistance may potentially contribute to the pathogenesis of tardive dyskinesia. Findings from this small cross-sectional study suggest a possible relationship that requires clarification through larger, longitudinal studies.