Can the 128-Hz tuning fork be an alternative to the biothesiometer for diabetic peripheral neuropathy screening? A cross-sectional study in a tertiary hospital in East India.

INTRODUCTION: Diabetic neuropathy is frequently underdiagnosed and undertreated. Logistic problems accompany the routine use of the biothesiometer. Hence, we attempted to find a more easily available alternative. RESEARCH DESIGN AND METHODS: 149 patients with diabetes visiting the outpatient endocrinology clinic were assessed for vibration sense using a 128-Hz tuning fork (absolute timing method) and a biothesiometer. A reading of >25 V on the biothesiometer (known as vibration perception threshold or VPT) was taken as the diagnostic criterion for severe neuropathy while >15 V was used as an indicator of the mild form. The sensitivity and specificity were calculated by constructing the receiver operating characteristic curve (ROC). A p value of <0.05 was considered as statistically significant. RESULTS: The timed tuning fork (TTF) test showed a statistically significant correlation with the VPT measurements (r=-0.5, p=0.000). Using the VPT findings as a reference, a timed tuning fork cut-off of 4.8 s was 76% sensitive and 77% specific in diagnosing mild neuropathy while absent tuning fork sensation demonstrated 70% sensitivity and 90% specificity in detecting severe neuropathy. CONCLUSIONS: The tuning fork test demonstrated significant sensitivity and specificity in diagnosing diabetic peripheral neuropathy when compared against the biothesiometer. A cut-off of 4.8 s can be a useful indicator of the early stages of onset of the condition.

Rare coexistence of hypopituitarism with osteogenesis imperfecta - A double-trouble for bone.

Osteogenesis imperfecta (OI) commonly involving defects in COL1A1 and COL1A2 is a rare hereditary disease of bone fragility affecting 6-7 per 100,000 population. On the other hand, hypopituitarism is a separate entity that manifests with reduced levels of pituitary hormones. The cooccurrence of these two is seldom reported previously in literature as a deviation from Occam's razor. Here, we reported a case of pathological fracture in a 31-year-old male who had blue sclera and secondary adrenal insufficiency, hypogonadotropic hypogonadism, and growth hormone deficiency along with primary autoimmune hypothyroidism. Diagnosis of OI was suggested by heterozygous missense variant in exon 40 of the COL1A2 gene (chr7: g.94423092G > A; Depth: 99×) that resulted in the amino acid substitution of Serine for Glycine at codon 847. Replacement of glucocorticoid, levothyroxine, and testosterone was started along with antiresorptive therapy for better bone health outcomes.

Laron Syndrome: A Tale of Two Siblings.

Primary growth hormone (GH) resistance or growth hormone insensitivity syndrome, also called Laron syndrome, is a hereditary disease caused by mutations in the GH receptor or in the post-receptor signaling pathway. This disorder is characterized by postnatal growth failure resembling GH deficiency. Differentiating the two conditions is necessary. We present the cases of two siblings, a 16-year-old female and a 9-year-old male, born from a consanguineous union. Both had normal birth weights with subsequent severe short stature and delayed teeth eruption, with no features suggestive of any systemic illness. Serum insulin-like growth factor 1 (IGF1) and insulin-like growth factor binding protein 3 (IGFBP3) were both low. Suspecting GH deficiency, provocative testing with clonidine was done revealing peak growth hormone >40 ng/mL in both patients. In view of low IGF1 and IGFBP3 and high GH on stimulation, IGF1 generation test was done for both siblings, with values supporting the diagnosis of GH insensitivity or Laron syndrome.

Swyer Syndrome Presenting as Dysgerminoma: A Case Report.

Complete gonadal dysgenesis with 46,XY karyotype is a clinical condition characterized by the absence of testicular tissue but with the presence of typical Müllerian structures in a phenotypically female individual. The condition presents as primary amenorrhoea or delayed puberty. Eventually, malignant neoplasms may arise. We report a case of a 16-year-old Indian male with Swyer syndrome presenting with primary amenorrhoea and with an earlier diagnosis of a malignant dysgerminoma in the right ovary.

Diagnostic approach in 46, XY DSD: an endocrine society of bengal (ESB) consensus statement.

OBJECTIVES: 46, XY difference/disorder of sex development (DSD) is a relatively uncommon group of heterogeneous disorders with varying degree of underandrogenization of male genitalia. Such patients should be approached systematically to reach an aetiological diagnosis. However, we lack, at present, a clinical practice guideline on diagnostic approach in 46, XY DSD from this part of the globe. Moreover, debate persists regarding the timing and cut-offs of different hormonal tests, performed in these cases. The consensus committee consisting of 34 highly experienced endocrinologists with interest and experience in managing DSD discussed and drafted a consensus statement on the diagnostic approach to 46, XY DSD focussing on relevant history, clinical examination, biochemical evaluation, imaging and genetic analysis. CONTENT: The consensus was guided by systematic reviews of existing literature followed by discussion. An initial draft was prepared and distributed among the members. The members provided their scientific inputs, and all the relevant suggestions were incorporated. The final draft was approved by the committee members. SUMMARY: The diagnostic approach in 46, XY DSD should be multidisciplinary although coordinated by an experienced endocrinologist. We recommend formal Karyotyping, even if Y chromosome material has been detected by other methods. Meticulous history taking and thorough head-to-toe examination should initially be performed with focus on external genitalia, including location of gonads. Decision regarding hormonal and other biochemical investigations should be made according to the age and interpreted according to age-appropriate norms Although LC-MS/MS is the preferred mode of steroid hormone measurements, immunoassays, which are widely available and less expensive, are acceptable alternatives. All patients with 46, XY DSD should undergo abdominopelvic ultrasonography by a trained radiologist. MRI of the abdomen and/or laparoscopy may be used to demonstrate the Mullerian structure and/or to localize the gonads. Genetic studies, which include copy number variation (CNV) or molecular testing of a candidate gene or next generation sequencing then should be ordered in a stepwise manner depending on the clinical, biochemical, hormonal, and radiological findings. OUTLOOK: The members of the committee believe that patients with 46, XY DSD need to be approached systematically. The proposed diagnostic algorithm, provided in the consensus statement, is cost effective and when supplemented with appropriate genetic studies, may help to reach an aetiological diagnosis in majority of such cases.

An Observational Study showing Dipeptidyl Peptidase-4 (DPP-4) Activity and Gene Expression Variation in Chronic Liver Disease (CLD) Patients from a Tertiary Care Hospital of Eastern India.

Introduction: The studies in animal models of cirrhosis suggest that dipeptidyl peptidase type 4 (DPP-4) enzymes play a crucial role in disease pathogenesis. In this clinical observational study, activity of DPP-4 and related gene expression were analysed in chronic liver disease patients. Objectives: To understand the DPP-4 enzyme activity variation in the common types of chronic liver disease by assessing plasma and peripheral blood mononuclear cell (PBMC) DPP-4 activity and comparing with healthy controls and to explore DPP-4 gene expression in PBMC. Methods: We recruited 130 study subjects in four cohorts-46 nonalcoholic fatty liver disease (NAFLD), 23 non-alcoholic cirrhosis (NAC) excluding viral aetiology, 21 alcoholic liver disease (ALC), and 40 control subjects. Blood samples were analysed for relevant biochemical parameters and plasma DPP-4 activity. PBMC fraction was used for the DPP-4 activity assay and gene expression analysis. Results: We found that lower plasma DPP-4 activity among patient cohorts but this was not statistically significant. The PBMC DPP-4 activity was significantly lower in NAFLD cohort. In the same cohort, DPP-4 gene expression in PBMC fraction was significantly increased (P < 0.05). There was significant correlation between plasma DPP-4 activity and liver injury marker alanine aminotransferase (ALT) among NAFLD (rho = 0.459, P < 0.01), NAC (rho = 0.475, P < 0.05), and ALC (rho = -0.572, P < 0.01) patients. Plasma DPP-4 activity modestly predicted ALT plasma level (beta coefficient = 0.489, P < 0.01). Conclusions: The PBMC DPP-4 activity and DPP-4 gene expression gets significantly altered in NAFLD patients. Plasma DPP-4 activity also shows correlation with ALT levels in CLD patients. The role of DPP-4 in disease pathology in NAFLD and other forms of CLD needs to be explored.

A Case of Elephantiasic Pretibial Myxedema Successfully Treated With Intralesional Triamcinolone Acetate.

Graves' dermopathy is one of the extra-thyroidal manifestations of Graves' disease (GD) and is characterized by the accumulation of glycosaminoglycans in the reticular dermis. In the majority of cases, pretibial myxedema is self-limiting but, in some cases, it can lead to structural and functional damage. Topical steroids with occlusive dressing remain the conventional treatment, but intralesional steroids have shown promising results. We hereby present a case of pretibial myxedema treated successfully with intralesional triamcinolone acetate.

Transformation of Peripheral Sexual Precocity to Central Sexual Precocity Following Treatment of Granulosa Cell Tumor of the Ovary.

Juvenile granulosa cell tumor leading to isosexual peripheral precocious puberty is a well-known association. Here, we report a rare case of central precocious puberty secondary to granulosa cell tumor of the ovary. A five-year and five-month-old girl presented with a history of progressive enlargement of bilateral breasts and intermittent vaginal spotting, associated with growth acceleration. Elevated estradiol and suppressed serum follicle-stimulating hormone were found on investigation. Additionally, abdominal and pelvic ultrasonography was suggestive of a right ovarian mass, which proved to be a juvenile granulosa cell tumor on histopathology and immunohistochemistry, leading to a diagnosis of peripheral precocious puberty secondary to granulosa cell tumor of the ovary. One and a half years after resection of the tumor, secondary sexual characteristics progressed with regression of tumor markers, and no mass was noted on ultrasonography, leading to the suspicion of central precocious puberty. Pubertal basal luteinizing hormone (LH) and elevated triptorelin-stimulated LH confirmed the diagnosis of central precocious puberty secondary to granulosa cell tumor of the ovary.

Myriad Manifestations of 3-Beta-Hydroxysteroid Dehydrogenase 2 Deficiency-A Tale of Two Infants.

3-Beta-hydroxysteroid dehydrogenase type 2 (3ß-HSD2) deficiency is a rare variety of congenital adrenal hyperplasia. Based on the severity of the enzymatic defect, it can present with a salt-wasting crisis in both sexes to undervirilization in males and virilization in females. We report two cases of infants with extremes of presentation of this congenital adrenal hyperplasia. First was a 28-day-old child presenting with a salt-wasting crisis while the other was a one-month-old child presenting with ambiguous genitalia. Clinical exome sequencing of the first child confirmed the diagnosis and we report a novel mutation of this gene, while the second child was diagnosed biochemically by raised synacthen-stimulated 17-OH-pregnenolone. The first case was managed with glucocorticoid and mineralocorticoid supplementation, while the second child was managed conservatively. Due to variable presentations, 3ß-HSD2 deficiency should be kept as a differential diagnosis while evaluating a child with congenital adrenal hyperplasia.

Absence of Vitamin D Deficiency Among Outdoor Workers With Type 2 Diabetes Mellitus in Southern West Bengal, India.

BACKGROUND: Vitamin D deficiency is widespread globally and is associated with type 2 diabetes mellitus (T2DM). Studies suggest markedly lower prevalence of vitamin D deficiency in outdoor workers compared to indoor workers. However, data on the vitamin D status of outdoor workers with T2DM is lacking. AIMS: We assessed the vitamin D status of outdoor workers with T2DM residing across several districts of Southern West Bengal, India. DESIGN: The present study is a descriptive observational study. MATERIAL AND METHODS: A total of 128 outdoor workers with T2DM were assessed for serum 25-hydroxyvitamin D (25(OH)D) during December 2019 after excluding common confounders except sun exposure (which was detailed using a questionnaire). Hospital staff were indoor controls, and vitamin D status was classified as per the Institute of Medicine guidelines. RESULTS: The mean serum 25(OH)D of outdoor workers with T2DM was 21.79 ± 6.31 ng/mL, with only 2.34% (n = 3) having vitamin D deficiency and 57.03% (n = 73) having sufficient serum 25(OH)D levels. The mean serum 25(OH)D of indoor controls was significantly lower at 16.67 ± 9.82 ng/mL (p = 0.003), with 33.33% being vitamin D deficient. Serum 25(OH)D in outdoor workers with T2DM did not have a significant correlation with indices of sun exposure. CONCLUSIONS: Vitamin D deficiency is practically absent in outdoor workers with T2DM residing in Southern West Bengal, India.

A Novel Homozygous CYP19A1 Gene Mutation Causing Aromatase Deficiency.

Aromatase deficiency is a rare autosomal recessive disorder and its exact prevalence is not known. Aromatase enzyme catalyzes the conversion of androgens to estrogens in gonadal and extra-gonadal tissues. Deficiency of aromatase enzyme can lead to ambiguous genitalia in a female child and maternal virilization during pregnancy due to raised androgen levels in the mother. A 10-month-old child was referred to our outpatient department for the evaluation of ambiguous genitalia. There was a history of maternal virilization during pregnancy. Karyotype of the child was 46XX. Congenital adrenal hyperplasia was ruled out as serum cortisol, plasma adrenocorticotropic hormone, and 17-hydroxyprogesterone were within normal limits. Hormonal assays showed elevated follicle-stimulating hormone and luteinizing hormone, with raised testosterone and low estradiol levels. Based on these findings, aromatase deficiency was suspected. A novel homozygous mutation c.1376delA located on exon 10 was identified on the CYP19A1 gene. We identified a novel mutation in the CYP19A1 gene in a patient who presented with ambiguous genitalia and maternal virilization during pregnancy.

Pharmacokinetic and pharmacodynamic bioequivalence of biosimilar MYL-1601D with US and European insulin aspart in healthy volunteers: A randomized, double-blind, crossover, euglycaemic glucose clamp study.

AIM: To evaluate the pharmacokinetic (PK) and pharmacodynamic (PD) bioequivalence (BE) of MYL-1601D biosimilar with originator, NovoLog (Ref-InsAsp-US), and NovoRapid (Ref-InsAsp-EU). MATERIALS AND METHODS: This was a double-blind, randomized, crossover study that enrolled 71 healthy subjects to receive a single subcutaneous dose (0.2 U/kg) of each formulation under automated euglycaemic clamp conditions (ClampArt, level 81 mg/dL, duration 12 hours postdose). Primary PK endpoints were area under the plasma insulin aspart concentration-time curve from 0 to 12 hours (AUC0-12h ) and maximum plasma insulin aspart concentration (Cmax ). Primary PD endpoints were area under the glucose infusion rate (GIR) time curve from 0 to 12 hours (AUCGIR0-12h ) and maximum GIR (GIRmax ). Insulin aspart in plasma was quantified using immunoaffinity purification followed by ultraperformance liquid chromatography and tandem mass spectrometric detection. The pairwise comparisons of geometric least square mean (LS-mean) ratio for a 90% confidence interval (CI) of primary PK, and 90% CIs (MYL-1601D vs. Ref-InsAsp-US) and 95% CIs (MYL-1601D vs. Ref-InsAsp-EU) of primary PD variables, were to be within 80% to 125% to show BE. RESULTS: MYL-1601D showed PK BE to both Ref-InsAsp-US (AUC0-12h geometric LS-mean ratio 102.17, 90% CI [100.26; 104.11]; Cmax 106.13 [100.71; 111.85]) and Ref-InsAsp-EU (AUC0-12h 101.84 [100.04; 103.67]; Cmax 105.74 [101.09; 110.60]). Likewise, MYL-1601D showed PD BE to Ref-InsAsp-US (AUCGIR_0-last 99.93; 90% CI [95.74; 104.30]; GIR_max 100.12 [94.46; 106.12]) and Ref-InsAsp-EU (AUCGIR_0-last 96.42; 95% CI [91.17; 101.98]; GIR_max 95.10 [89.37; 101.19]). All three insulin aspart products were well tolerated. CONCLUSION: MYL-1601D showed BE to Ref-InsAsp-US and Ref-InsAsp-EU with a comparable safety profile.

Similar immunogenicity profiles between the proposed biosimilar MYL-1501D and reference insulin glargine in patients with diabetes mellitus: the phase 3 INSTRIDE 1 and INSTRIDE 2 studies.

BACKGROUND: MYL-1501D is a proposed biosimilar to insulin glargine. The noninferiority of MYL-1501D was demonstrated in patients with type 1 diabetes and type 2 diabetes in 2 phase 3 trials. Immunogenicity of MYL-1501D and reference insulin glargine was examined in both studies. METHODS: INSTRIDE 1 and INSTRIDE 2 were multicenter, open-label, randomized, parallel-group studies. In INSTRIDE 1, patients with type 1 diabetes received MYL-1501D or insulin glargine over a 52-week period. In INSTRIDE 2, patients with type 2 diabetes treated with oral antidiabetic drugs, insulin naive or not, received MYL-1501D or reference insulin glargine over a 24-week period. Incidence rates and change from baseline in relative levels of antidrug antibodies (ADA) and anti-host cell protein (anti-HCP) antibodies in both treatment groups were determined by a radioimmunoprecipitation assay and a bridging immunoassay, respectively. Results were analyzed using a mixed-effects model (INSTRIDE 1) or a nonparametric Wilcoxon rank sum test (INSTRIDE 2). RESULTS: Total enrollment was 558 patients in INSTRIDE 1 and 560 patients in INSTRIDE 2. The incidence of total and cross-reactive ADA was comparable between treatment groups in INSTRIDE 1 and INSTRIDE 2 (P > 0.05 for both). A similar proportion of patients had anti-HCP antibodies in both treatment groups in INSTRIDE 1 at week 52 (MYL-1501D, 93.9 %; reference insulin glargine, 89.6 %; P = 0.213) and in INSTRIDE 2 at week 24 (MYL-1501D, 87.3 %; reference insulin glargine, 86.9 %; P > 0.999). CONCLUSIONS: In INSTRIDE 1 and INSTRIDE 2, similar immunogenicity profiles were observed for MYL-1501D and reference insulin glargine in patients with type 1 diabetes and type 2 diabetes, respectively. TRIAL REGISTRATION: ClinicalTrials.gov, INSTRIDE 1 ( NCT02227862 ; date of registration, August 28, 2014); INSTRIDE 2 ( NCT02227875 ; date of registration, August 28, 2014).

Kidney Disease in Type 2 Diabetes Mellitus and Benefits of Sodium-Glucose Cotransporter 2 Inhibitors: A Consensus Statement.

Diabetic kidney disease (DKD) occurs in approximately 20-40% of patients with type 2 diabetes mellitus. Patients with DKD have a higher risk of cardiovascular and all-cause mortality. Angiotensin-converting enzyme inhibitors or angiotensin receptor blockers and antihyperglycemic drugs form the mainstay of DKD management and aim to restrict progression to more severe stages of DKD. Sodium-glucose cotransporter 2 inhibitors (SGLT2i) control hyperglycemia by blocking renal glucose reabsorption in addition to preventing inflammation, thereby improving endothelial function and reducing oxidative stress; consequently, this class of prescription medicines is emerging as an important addition to the therapeutic armamentarium. The EMPA-REG OUTCOME, DECLARE TIMI 58, and CANVAS trials demonstrated the renoprotective effects of SGLT2i, such as restricting decline in glomerular filtration rate, in the progression of albuminuria, and in death due to renal causes. The renoprotection provided by SGLT2i was further confirmed in the CREDENCE study, which showed a 30% reduction in progression of chronic kidney disease, and in the DELIGHT study, which demonstrated a reduction in albuminuria with dapagliflozin compared with placebo (- 21.0%, confidence interval [CI] - 34.1 to - 5.2, p = 0.011). Furthermore, a meta-analysis demonstrated a reduced risk of dialysis, transplantation, or death due to kidney disease (relative risk 0.67; 95% CI 0.52-0.86; p = 0.0019) and a 45% risk reduction in worsening of renal function, end-stage renal disease, or renal death (hazard ratio 0.55, CI 0.48-0.64, p < 0.0001) with SGLT2i, irrespective of baseline estimated glomerular filtration rate. Thus, there is emerging evidence that SGLT2i may be used to curb the mortality and improve the quality of life in patients with DKD. However, clinicians need to effectively select candidates for SGLT2i therapy. In this consensus statement, we have qualitatively synthesized evidence demonstrating the renal effects of SGLT2i and proposed recommendations for optimal use of SGLT2i to effectively manage and delay progression of DKD.

Management of asymptomatic hyperuricemia: Integrated Diabetes & Endocrine Academy (IDEA) consensus statement.

AIM: The definition and management of asymptomatic hyperuricemia has been an area of controversy for many decades. Debate persists regarding the benefit of treating all cases of asymptomatic hyperuricemia and hence, unsurprisingly there are no clear clinical practice guidelines from our country. PARTICIPANTS: Ten members consisting of eminent physicians, endocrinologists, nephrologist and a rheumatologist were selected by the Integrated Diabetes & Endocrine Academy (IDEA) for a closed meeting with the aim to come to a consensus. EVIDENCE: A literature search was performed using PubMed and Cochrane library following which published articles in indexed peer review journals were selected. CONSENSUS PROCESS: Each participant voiced their opinion after reviewing the available data and a consensus was reached after three meetings by voting. CONCLUSION: Recommendations were made on important areas such as definition, investigation and management of asymptomatic hyperuricemia.

Type 2 diabetes and influence of diabetes-specific distress on depression.

AIMS: Common psycho-social emotional reactions of patients with diabetes may be termed as diabetes-specific distress which is conceptually distinctive from depression. In patients with type 2 diabetes, different screening methods for depression may get influenced by simultaneous presence of diabetes distress. This study was planned to assess magnitude and relationship of depression and diabetes specific distress in patients with type 2 diabetes. METHODS: Two hundred and fifty (250) adult patients with type 2 diabetes (T2DM) were assessed for depression based on Beck Depression Inventory (BDI) and Diagnostic and Statistical Manual, Fourth edition (DSM IV) criteria. Diabetes specific distress was assessed as per Diabetes Distress Scale (DDS) score. RESULTS: Among study population of 250 adult T2DM patients, based on BDI score, 97 (38.8%) patients were found to suffer from depression and based on DSM IV criteria, prevalence of depression was 29.2%. A total of 62 (24.8%) patients were found to suffer from diabetes specific distress based on DDS score. Patients with severe diabetes specific distress had associated matching of symptoms with mild depression based on BDI score which was also statistically significant (p < 0.0001). However, these same individuals were non-depressed as per DSM-IV criteria. CONCLUSION: Recognizing depression with self-administered questionnaires may be influenced by concomitant presence of symptoms due to diabetes specific distress. Therefore, proper diagnosis of depression may be established by structured clinical interview and psycho-social management of type 2 diabetes should possibly include both assessment of depression and diabetes specific distress.

A pharmacokinetics phase 1 bioequivalence study of the trastuzumab biosimilar MYL-1401O vs. EU-trastuzumab and US-trastuzumab.

AIMS: Trastuzumab is a humanized monoclonal antibody that binds the human epidermal growth factor receptor 2 (HER2) oncoprotein and is an effective therapy for HER2-overexpressing breast cancer. MYL-1401O is a trastuzumab biosimilar. Here, we report results from a phase 1 study that investigated bioequivalence among MYL-1401O, reference EU-trastuzumab and US-trastuzumab. METHODS: This single-centre, randomized, double-blind, three-arm, parallel-group, phase 1 study was conducted in healthy adult male volunteers. Subjects were randomized 1:1:1 to receive a single 8 mg kg-1 dose of MYL-1401O, EU-trastuzumab or US-trastuzumab as a 90-min intravenous infusion. The primary objective was to assess PK similarity among all three products. Primary endpoints assessed were peak serum concentration (Cmax), area under the serum concentration-time curve from time of dosing to time of last quantifiable concentration and from time of dosing to infinity. Secondary endpoints included time of Cmax, elimination rate constant, half-life, safety and immunogenicity. RESULTS: Of 132 subjects enrolled (44/treatment), 120 (MYL-1401O, n = 42; EU-trastuzumab, n = 41; US-trastuzumab, n = 37) were included in the PK analysis. The 90% confidence intervals of the ratios of geometric means for the primary endpoints were bounded within the predefined bioequivalence criterion of 80-125%. Secondary endpoints time of Cmax, elimination rate constant and half-life were similar among groups. All treatment-emergent adverse events were mild or moderate, similar across groups and no serious adverse events were reported. No treatment-related antidrug antibodies were detected. CONCLUSIONS: MYL-1401O was well tolerated and demonstrated PK and safety profiles similar to EU-trastuzumab and US-trastuzumab in healthy volunteers (ClinicalTrials.gov, NCT02594761).

Development and validation of a cell based assay for the detection of neutralizing antibodies against recombinant insulins.

Recombinant biopharmaceuticals can induce generation of anti-drug antibodies, which could potentially neutralize therapeutic drug activity. In this report, we describe development and validation of a cell-based assay for detection of neutralizing antibodies (Nab) against insulin and insulin analogues. In order to achieve clinically meaningful sensitivity the method used an early signalling event, insulin induced insulin receptor phosphorylation as the endpoint. Percentage insulin receptor phosphorylation in cell lysates was measured using ECL based ELISA. Presence of neutralizing antibodies (Nab) in samples will inhibit insulin induced receptor phosphorylation and consequently lead to a reduction in the percentage of phosphorylated insulin receptor. Additionally, usage of human insulin receptor overexpressing recombinant CHO cell line further improved the assay sensitivity by reducing the fixed drug (EC50) concentration used for induction of receptor phosphorylation. To ensure adequate free drug tolerance a pre-treatment step was introduced, where serum samples underwent acid dissociation and charcoal extraction before drug incubation. In order to distinguish ADA positive samples containing true Nab from samples containing non-antibody phosphorylation inhibitory serum factors, a confirmatory tier was integrated based on immunodepletion using protein AGL mix. Assay parameters including determination of screening and confirmatory cut-points, intra and inter assay precision, selectivity, specificity and stability were assessed during validation in accordance with recent regulatory guidelines and white papers. The advantage of selecting insulin receptor phosphorylation as assay endpoint made the assay capable of detecting Nab against insulin and insulin analogues.

Development and validation of an electrochemiluminescent ELISA for quantitation of oral insulin tregopil in diabetes mellitus serum.

AIM: Tregopil, a novel PEGylated human insulin is in clinical development for oral delivery in diabetes treatment. The aim of the study was to develop and validate a sensitive and specific ELISA method for quantitating Tregopil in diabetes subjects on basal Glargine, since most commercially available insulin kits either do not detect Tregopil or show significant reactivity to Glargine. METHODS: An electrochemiluminescent ELISA was developed and validated for Tregopil quantitation in diabetes serum. RESULTS: The method has a LLOQ of 0.25 ng/ml, shows minimum cross-reactivity to Glargine and was successfully tested using a subset of samples from Tregopil-dosed Type 1 diabetes mellitus patients. CONCLUSION: The ELISA method is sensitive and can be used to support accurate measurement of Tregopil with no cross-reactivity to Glargine and its metabolites in clinical studies.