Stephen C. L. Gough

Negligible impact of rare autoimmune-locus coding-region variants on missing heritability

Genome-wide association studies (GWAS) have identified common variants of modest-effect size at hundreds of loci for common autoimmune diseases; however, a substantial fraction of heritability remains unexplained, to which rare variants may contribute. To discover rare variants and test them for association with a phenotype, most studies re-sequence a small initial sample size and then genotype the discovered variants in a larger sample set. This approach fails to analyse a large fraction of the rare variants present in the entire sample set. Here we perform simultaneous amplicon-sequencing-based variant discovery and genotyping for coding exons of 25 GWAS risk genes in 41,911 UK residents of white European origin, comprising 24,892 subjects with six autoimmune disease phenotypes and 17,019 controls, and show that rare coding-region variants at known loci have a negligible role in common autoimmune disease susceptibility. These results do not support the rare-variant synthetic genome-wide-association hypothesis (in which unobserved rare causal variants lead to association detected at common tag variants). Many known autoimmune disease risk loci contain multiple, independently associated, common and low-frequency variants, and so genes at these loci are a priori stronger candidates for harbouring rare coding-region variants than other genes. Our data indicate that the missing heritability for common autoimmune diseases may not be attributable to the rare coding-region variant portion of the allelic spectrum, but perhaps, as others have proposed, may be a result of many common-variant loci of weak effect.

Efficacy and safety of a fixed-ratio combination of insulin degludec and liraglutide (IDegLira) compared with its components given alone: results of a phase 3, open-label, randomised, 26-week, treat-to-target trial in insulin-naive patients with type 2 diabetes

BACKGROUND A fixed-ratio combination of the basal insulin analogue insulin degludec and the glucagon-like peptide-1 (GLP-1) analogue liraglutide has been developed as a once-daily injection for the treatment of type 2 diabetes. We aimed to compare combined insulin degludec-liraglutide (IDegLira) with its components given alone in insulin-naive patients. METHODS In this phase 3, 26-week, open-label, randomised trial, adults with type 2 diabetes, HbA1c of 7-10% (inclusive), a BMI of 40 kg/m(2) or less, and treated with metformin with or without pioglitazone were randomly assigned (2:1:1) to daily injections of IDegLira, insulin degludec, or liraglutide (1·8 mg per day). IDegLira and insulin degludec were titrated to achieve a self-measured prebreakfast plasma glucose concentration of 4-5 mmol/L. The primary endpoint was change in HbA1c after 26 weeks of treatment, and the main objective was to assess the non-inferiority of IDegLira to insulin degludec (with an upper 95% CI margin of 0·3%), and the superiority of IDegLira to liraglutide (with a lower 95% CI margin of 0%). This study is registered with ClinicalTrials.gov, number NCT01336023. FINDINGS 1663 adults (mean age 55 years [SD 10], HbA1c 8·3% [0·9], and BMI 31·2 kg/m(2) [4·8]) were randomly assigned, 834 to IDegLira, 414 to insulin degludec, and 415 to liraglutide. After 26 weeks, mean HbA1c had decreased by 1·9% (SD 1·1) to 6·4% (1·0) with IDegLira, by 1·4% (1·0) to 6·9% (1·1) with insulin degludec, and by 1·3% (1·1) to 7·0% (1·2) with liraglutide. IDegLira was non-inferior to insulin degludec (estimated treatment difference -0·47%, 95% CI -0·58 to -0·36, p<0·0001) and superior to liraglutide (-0·64%, -0·75 to -0·53, p<0·0001). IDegLira was generally well tolerated; fewer participants in the IDegLira group than in the liraglutide group reported gastrointestinal adverse events (nausea 8·8 vs 19·7%), although the insulin degludec group had the fewest participants with gastrointestinal adverse events (nausea 3·6%). We noted no clinically relevant differences between treatments with respect to standard safety assessments, and the safety profile of IDegLira reflected those of its component parts. The number of confirmed hypoglycaemic events per patient year was 1·8 for IDegLira, 0·2 for liraglutide, and 2·6 for insulin degludec. Serious adverse events occurred in 19 (2%) of 825 patients in the IDegLira group, eight (2%) of 412 in the insulin degludec group, and 14 (3%) of 412 in the liraglutide group. INTERPRETATION IDegLira combines the clinical advantages of basal insulin and GLP-1 receptor agonist treatment, resulting in improved glycaemic control compared with its components given alone. FUNDING Novo Nordisk.

The Efficacy and Safety of Insulin Degludec Given in Variable Once-Daily Dosing Intervals Compared With Insulin Glargine and Insulin Degludec Dosed at the Same Time Daily: A 26-week, randomized, open-label, parallel-group, treat-to-target trial in individuals with type 2 diabetes

OBJECTIVE The requirement to inject current basal insulin analogs at a fixed time each day may complicate adherence and compromise glycemic control. This trial evaluated the efficacy and safety of varying the daily injection time of insulin degludec (IDeg), an ultra-long-acting basal insulin. RESEARCH DESIGN AND METHODS This 26-week, open-label, treat-to-target trial enrolled adults (≥18 years) with type 2 diabetes who were either insulin naïve and receiving oral antidiabetic drugs (OADs) (HbA1c = 7–11%) or previously on basal insulin ± OAD(s) (HbA1c = 7–10%). Participants were randomized to 1) once-daily (OD) IDeg in a prespecified dosing schedule, creating 8–40-h intervals between injections (IDeg OD Flex; n = 229); 2) once-daily IDeg at the main evening meal (IDeg OD; n = 228); or 3) once-daily insulin glargine at the same time each day (IGlar OD; n = 230). The primary outcome was noninferiority of IDeg OD Flex to IGlar OD in HbA1c reduction after 26 weeks. RESULTS After 26 weeks, IDeg OD Flex, IDeg OD, and IGlar OD improved HbA1c by 1.28, 1.07, and 1.26% points, respectively (estimated treatment difference [IDeg OD Flex − IGlar OD]: 0.04% points [–0.12 to 0.20], confirming noninferiority). No statistically significant differences in overall or nocturnal hypoglycemia were found between IDeg OD Flex and IGlar OD. Comparable glycemic control and rates of hypoglycemia were seen with IDeg OD Flex and IDeg OD. Adverse event profiles were similar across groups. CONCLUSIONS The use of extreme dosing intervals of 8–40 h demonstrates that the daily injection time of IDeg can be varied without compromising glycemic control or safety.

Association of the TSHR gene with Graves' disease: the first disease specific locus

The development of autoimmune thyroid disease (AITD) is associated with autoantibodies directed against the thyroid stimulating hormone receptor (TSHR). Previous studies have failed to demonstrate a consistent association between the TSHR and AITD, or any of its sub-phenotypes. In the present study, we analysed the linkage disequilibrium (LD) structure encompassing the TSHR, to identify LD ‘blocks’ and SNPs, which capture the majority of intra-block haplotype diversity. The haplotype tagging SNPs, plus all common SNPs reported in previous studies were genotyped in 1059 AITD Caucasian cases and 971 Caucasian controls. A haplotype, across two LD blocks, showed association (P<1 × 10−6, OR 1.7) with Graves’ disease (GD) but not autoimmune hypothyroidism (AIH). We replicated these findings by genotyping the most associated GD SNP, rs2268458, in a separate UK Caucasian cohort of 1366 AITD cases and 1061 controls (GD, P=2 × 10−6, OR 1.3; AIH, P=NS). These results in two independent Caucasian data sets suggest that the TSHR is the first replicated GD-specific locus meriting further fine mapping and functional analysis to identify the aetiological variants.

Safety and efficacy of liraglutide in patients with type 2 diabetes and elevated liver enzymes: Individual patient data meta-analysis of the LEAD program

Non‐alcoholic fatty liver disease has reached epidemic proportions in type 2 diabetes (T2D). Glucagon‐like peptide‐1 analogues are licensed in T2D, yet little data exist on efficacy and safety in liver injury.

Achieving a clinically relevant composite outcome of an HbA1c of <7% without weight gain or hypoglycaemia in type 2 diabetes: a meta-analysis of the liraglutide clinical trial programme.

Aim: Effective type 2 diabetes management requires a multifactorial approach extending beyond glycaemic control. Clinical practice guidelines suggest targets for HbA1c, blood pressure and lipids, and emphasize weight reduction and avoiding hypoglycaemia. The phase 3 clinical trial programme for liraglutide, a human glucagon‐like peptide 1 analogue, showed significant improvements in HbA1c and weight with a low risk of hypoglycaemia compared to other diabetes therapies. In this context, we performed a meta‐analysis of data from these trials evaluating the proportion of patients achieving a clinically relevant composite measure of diabetes control consisting of an HbA1c <7% without weight gain or hypoglycaemia.

Low-Volume Insulin Degludec 200 Units/mL Once Daily Improves Glycemic Control Similarly to Insulin Glargine With a Low Risk of Hypoglycemia in Insulin-Naïve Patients With Type 2 Diabetes: A 26-week, randomized, controlled, multinational, treat-to-target trial: The BEGIN LOW VOLUME trial

OBJECTIVE The 200 units/mL formulation of insulin degludec (IDeg 200 units/mL) contains equal units of insulin in half the volume compared with the 100 units/mL formulation. We compared the efficacy and safety of IDeg 200 units/mL once daily with 100 units/mL insulin glargine (IGlar) in insulin-naïve subjects with type 2 diabetes (T2DM) inadequately controlled with oral antidiabetic drugs. RESEARCH DESIGN AND METHODS In this 26-week, open-label, treat-to-target trial, subjects (n = 457; mean HbA1c 8.3% [67 mmol/mol], BMI 32.4 kg/m2, and fasting plasma glucose [FPG] 9.6 mmol/L [173.2 mg/dL]) were randomized to IDeg 200 units/mL or IGlar, both given once daily in combination with metformin with or without a dipeptidyl peptidase-4 inhibitor. Basal insulin was initiated at 10 units/day and titrated weekly to an FPG target of <5 mmol/L (<90 mg/dL) according to mean prebreakfast self-measured blood glucose values from the preceding 3 days. RESULTS By 26 weeks, IDeg reduced HbA1c by 1.30% and was not inferior to IGlar. Mean observed FPG reductions were significantly greater with IDeg than IGlar (−3.7 vs. −3.4 mmol/L [–67 vs. –61 mg/dL]; estimated treatment difference: −0.42 [95% CI −0.78 to −0.06], P = 0.02). Despite this difference, rates of overall confirmed hypoglycemia were not higher with IDeg than with IGlar (1.22 and 1.42 episodes/patient-year, respectively), as were rates of nocturnal confirmed hypoglycemia (0.18 and 0.28 episodes/patient-year, respectively). Mean daily basal insulin dose was significantly lower by 11% with IDeg 200 units/mL compared with IGlar. IDeg was well-tolerated, and the rate of treatment-emergent adverse events was similar across groups. CONCLUSIONS In this treat-to-target trial in insulin-naïve patients with T2DM, IDeg 200 units/mL improved glycemic control similarly to IGlar with a low risk of hypoglycemia.

Polymorphism of the CTLA-4 gene is associated with autoimmune hypothyroidism in the United Kingdom.

The cytotoxic T-lymphocyte-associated-4 (CTLA-4) molecule plays an important role in immune regulation by downregulating activation of T cells by antigen-presenting cells. Polymorphisms of the CTLA-4 gene have been shown to be associated with susceptibility to a number of autoimmune diseases. Some, but not all, studies suggest association between the CTLA-4 gene and autoimmune hypothyroidism. The aim of this study was to determine whether allelic association was present between the A-G single nucleotide polymorphism (SNP) at position 49 in exon 1 of the CTLA-4 gene and autoimmune hypothyroidism. The study was performed in 158 patients with autoimmune hypothyroidism and 384 control subjects. All subjects were white Caucasians from the United Kingdom. Genotyping was carried out by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) using the restriction enzyme Bbv1. There was a significant excess of the G allele in patients with autoimmune hypothyroidism compared with controls (43% vs. 32% respectively; chi2 = 10.7, p = 0.001; odds ratio 1.57). The GG and the AG genotypes were found to be more frequent in patients with autoimmune hypothyroidism than controls (17% vs. 8.8% and 50% vs. 46% respectively; chi2 = 11.7, p = 0.003). These results suggest that the CTLA-4 gene region on chromosome 2q33 is a susceptibility locus for autoimmune hypothyroidism in the United Kingdom.

Glucagon-like peptide 1 decreases lipotoxicity in non-alcoholic steatohepatitis.

Graphical abstract

One-year efficacy and safety of a fixed combination of insulin degludec and liraglutide in patients with type 2 diabetes: results of a 26-week extension to a 26-week main trial

To confirm, in a 26‐week extension study, the sustained efficacy and safety of a fixed combination of insulin degludec and liraglutide (IDegLira) compared with either insulin degludec or liraglutide alone, in patients with type 2 diabetes.