A 1-year pilot study of intralymphatic injections of GAD-alum in individuals with latent autoimmune diabetes in adults (LADA) with signs of high immunity: No safety concerns and resemblance to juvenile type 1 diabetes

AIMS

To test, for the first time in latent autoimmune diabetes in adults (LADA), the effects of autoantigen-specific immunotherapy by intralymphatic administration of aluminium-formulated recombinant human glutamic acid decarboxylase 65 (GAD-alum); specifically, to test if this treatment is safe, to test whether it induces a strong immunological response akin to a similar protocol in type 1 diabetes and to look for associations with preserved beta-cell function.

MATERIALS AND METHODS

Three GAD-alum injections, 4 μg each, were administered 1 month apart into an inguinal lymph node in 14 people with newly diagnosed LADA (age 30-62 years) presenting with high levels of antibodies against glutamic acid decarboxylase (GADA). Adverse effects, immunological variables and beta-cell function were monitored, with detailed measurements at 5 and 12 months from baseline.

RESULTS

Clinical adverse effects were minor and transient and measured laboratory variables were unaffected. All participants completed the study. Treatment raised levels of GADA, elicited strong effects on reactivity of peripheral blood mononuclear cells to GAD and raised cytokine/chemokine levels. Beta-cell function appeared stable preferentially in the seven participants carrying human leukocyte antigen (HLA) haplotypes DR3DQ2, as assessed by C-peptide glucagon tests (P < 0.05 vs. seven non-carriers).

CONCLUSION

Intralymphatic treatment with GAD-alum in LADA is without clinical or other safety concerns over a 12-month period. As in a similar protocol used in type 1 diabetes, treatment exerts a strong immunological impact and is compatible with protection of beta-cell function preferentially in HLA-DR3DQ2 LADA patients. These findings pave the way for a randomized controlled trial in this important subgroup of LADA patients.

Diagnostic Dilemmas and Current Treatment Approaches in Latent Onset Autoimmune Diabetes in Adults: A Concise Review

Latent Onset Autoimmune Diabetes in Adults (LADA) is an autoimmune disorder between T1DM and T2DM and is often misdiagnosed as T2DM due to its late-onset. The disease is characterized by β-cell failure and slow progression to insulin dependence. Early diagnosis is significant in limiting disease progression. C-peptide levels and autoantibodies against β-cells are the most critical diagnostic biomarkers in LADA. The review aims to provide an overview of the biomarkers used to diagnose LADA, and the following treatment approaches. We have summarized LADA's pathophysiology and the autoantibodies involved in the condition, diagnostic approaches, and challenges. There are clear shortcomings concerning the feasibility of autoantibody testing. Finally, we have explored the treatment strategies involved in the management of LADA. In conclusion, the usual management includes treatment with metformin and the addition of low doses of insulin. Newer oral hypoglycaemic agents, such as GLP-1RA and DPP-4 inhibitors, have been brought into use. Since the disease is not entirely understood at the research level and in clinical practice, we hope to encourage further research in this field to assess its prevalence. Large randomized controlled trials are required to compare the efficacy of different available treatment options.

Latent Autoimmune Diabetes in Adults: Background, Safety and Feasibility of an Ongoing Pilot Study With Intra-Lymphatic Injections of GAD-Alum and Oral Vitamin D

BACKGROUND

Latent Autoimmune Diabetes in Adults (LADA) constitutes around 10% of all diabetes. Many LADA patients gradually lose their insulin secretion and progress to insulin dependency. In a recent trial BALAD (Behandling Av LADa) early insulin treatment compared with sitagliptin failed to preserve insulin secretion, which deteriorated in individuals displaying high levels of antibodies to GAD (GADA). These findings prompted us to evaluate a treatment that directly affects autoimmunity. Intra-lymphatic GAD-alum treatment has shown encouraging results in Type 1 diabetes patients. We therefore tested the feasibility of such therapy in LADA-patients (the GADinLADA pilot study).

MATERIAL AND METHODS

Fourteen GADA-positive (>190 RU/ml), insulin-independent patients 30-70 years old, with LADA diagnosed within < 36 months were included in an open-label feasibility trial. They received an intra-nodal injection of 4 μg GAD-alum at Day 1, 30 and 60 plus oral Vitamin D 2000 U/d from screening 30 days before (Day -30) for 4 months if the vitamin D serum levels were below 100 nmol/L (40 ng/ml). Primary objective is to evaluate safety and feasibility. Mixed Meal Tolerance Test and i.v. Glucagon Stimulation Test at baseline and after 5 and 12 months are used for estimation of beta cell function. Results will be compared with those of the recent BALAD study with comparable patient population. Immunological response is followed.

RESULTS

Preliminary results show feasibility and safety, with almost stable beta cell function and metabolic control during follow-up so far (5 months).

CONCLUSIONS

Intra-lymphatic GAD-alum treatment is an option to preserve beta cell function in LADA-patients. An ongoing trial in 14 LADA-patients show feasibility and safety. Clinical and immunological responses will determine how to proceed with future trials.

Efficacy of DPP-4 inhibitors and SGLT2 inhibitors compared to sulphonylureas in adult patients with diabetes with low c-peptide levels with or without anti-GAD65 antibody positivity

BACKGROUND AND AIMS

Latent Autoimmune Diabetes of Adulthood (LADA) is different from type 2 diabetes. Present treatment protocols do not reflect that. DPP-4 and SGLT2 inhibitors have changed therapy. DPP-4 inhibitor use has shown delayed decline in beta-cell reserve in LADA. We studied patients with low c-peptide to assess relationship between c-peptide and anti-GAD65 antibody levels and compare DPP-4 inhibitors with SGLT2 inhibitors and sulphonylureas.

METHODS

The study was an open-label trial conducted in 156 participants with low c-peptide (<0.8 ng/mL), age > 25 years, recently diagnosed diabetes with HBA1c ≥ 6.5%. Participants were enrolled into three arms: Group A received sulphonylureas + metformin, Group B received DPP-4 inhibitors + metformin, and Group C received SGLT-2 inhibitors + metformin. Serum anti-GAD-65 antibodies were assessed using sandwich ELISA. Participants were assessed on enrolment and after three months of dual pharmacotherapy.

RESULTS

The three arms were comparable on enrolment. 52% of participants with low c-peptide had high anti-GAD65 antibody titers. Significant differences were observed after three months - DPP-4 inhibitors reduced HbA1c by 1.1 ± 0.3%, compared to SGLT2 inhibitors (0.8 ± 0.13%) and sulphonylureas (0.7 ± 0.3%) CONCLUSION: DPP-4 inhibitors appear to provide better glycemic control than alternate therapeutic options in patients with low serum c-peptide.

Management of Latent Autoimmune Diabetes in Adults: A Consensus Statement From an International Expert Panel

A substantial proportion of patients with adult-onset diabetes share features of both type 1 diabetes (T1D) and type 2 diabetes (T2D). These individuals, at diagnosis, clinically resemble T2D patients by not requiring insulin treatment, yet they have immunogenetic markers associated with T1D. Such a slowly evolving form of autoimmune diabetes, described as latent autoimmune diabetes of adults (LADA), accounts for 2-12% of all patients with adult-onset diabetes, though they show considerable variability according to their demographics and mode of ascertainment. While therapeutic strategies aim for metabolic control and preservation of residual insulin secretory capacity, endotype heterogeneity within LADA implies a personalized approach to treatment. Faced with a paucity of large-scale clinical trials in LADA, an expert panel reviewed data and delineated one therapeutic approach. Building on the 2020 American Diabetes Association (ADA)/European Association for the Study of Diabetes (EASD) consensus for T2D and heterogeneity within autoimmune diabetes, we propose "deviations" for LADA from those guidelines. Within LADA, C-peptide values, proxy for β-cell function, drive therapeutic decisions. Three broad categories of random C-peptide levels were introduced by the panel: 1) C-peptide levels <0.3 nmol/L: a multiple-insulin regimen recommended as for T1D; 2) C-peptide values ≥0.3 and ≤0.7 nmol/L: defined by the panel as a "gray area" in which a modified ADA/EASD algorithm for T2D is recommended; consider insulin in combination with other therapies to modulate β-cell failure and limit diabetic complications; 3) C-peptide values >0.7 nmol/L: suggests a modified ADA/EASD algorithm as for T2D but allowing for the potentially progressive nature of LADA by monitoring C-peptide to adjust treatment. The panel concluded by advising general screening for LADA in newly diagnosed non-insulin-requiring diabetes and, importantly, that large randomized clinical trials are warranted.

Effect of extract from Boswellia serrata gum resin on decrease of GAD65 autoantibodies in a patient with Latent Autoimmune Diabetes in Adults

BACKGROUND

Extracts from Boswellia serrata gum resin have anti-inflammatory effect and are used for treatment of a variety of chronic inflammatory diseases. It was previously demonstrated that the treatment with Boswellia serrata gum resin of LADA (Latent Autoimmune Diabetes in Adults) patients decreased blood levels of IA2 antibodies, one of the markers associated with LADA autoimmune diabetes.

PRIMARY STUDY OBJECTIVE

The purpose of this study was to test whether Boswellia serrata gum resin also influences GAD65 autoantibodies as the other marker associated with LADA.

METHODS/DESIGN

We report a case study of male patient diagnosed with LADA with positive GAD65 autoantibodies who was treated with extract from Boswellia serrata gum resin, during 9 months. Blood levels of GAD65 autoantibodies, fasting blood glucose levels and HbA1c were measured before the treatment and periodically during the treatment.

RESULTS

Over the observed period, the blood levels of GAD65 autoantibodies linearly decreased about 25%.

CONCLUSION

The study confirms that extract of Boswellia serrata gum resin seems to prevent insulitis in patients with LADA, as indicated by its action on both markers of autoimmune diabetes, i.e., GAD65 and IA2 autoantibodies. The possibility that the treatment with boswellic acids of LADA patients with positive autoantibodies could be beneficial on the course of the disease, calls for further investigation and a clinical study.

Adding vitamin D3 to the dipeptidyl peptidase-4 inhibitor saxagliptin has the potential to protect β-cell function in LADA patients: A 1-year pilot study

AIMS

This trial was conducted to explore the protective effect on β-cell function of adding vitamin D3 to DPP-4 inhibitors to treat patients with latent autoimmune diabetes in adults (LADA).

METHODS

60 LADA patients were randomized to group A (n = 21) - conventional therapy with metformin (1-1.7 g/day) and/or insulin treatment; group B (n = 20) - saxagliptin (5 mg/day) plus conventional therapy; and group C (n = 19) - vitamin D3 (2000 IU/day) plus saxagliptin and conventional therapy for 12 months. Fasting and 2-hour postprandial blood samples were collected to measure blood glucose, glycosylated hemoglobin and C-peptide levels at baseline and after 3, 6 and 12 months of treatment.

RESULTS

During the 12 months of follow-up, the levels of fasting C-peptide (FCP), 2-hour postprandial C-peptide (PCP) and the C-peptide index (CPI, serum C-peptide-to-plasma glucose level ratio) were maintained in group C. In contrast to those in group A and group B, FCP levels decreased significantly in group B, and CPI levels declined significantly in group A during the 1-year treatment (P < .05). Additionally, the levels of GADA titers in group C significantly decreased compared with those at baseline (P < .05), but no significant differences in GADA titers levels were detected in group A and group B. No significant differences were found among the three groups in the levels of FCP, PCP, the CPI or GADA titers.

CONCLUSIONS

The data suggested that adding 2000 IU/day vitamin D3 to saxagliptin might preserve β-cell function in patients with LADA.

Exogenous Insulin Injection-Induced Stiff-Person Syndrome in a Patient With Latent Autoimmune Diabetes: A Case Report and Literature Review

Stiff-person syndrome (SPS) is highly associated with anti-glutamic acid decarboxylase (GAD) antibody. However, GAD antibodies alone appear to be insufficient to cause SPS, and they possibly are involved in only part of its pathophysiology. It is suspected that the symptoms of SPS get precipitated by external stimuli. Here, we briefly introduce the case of a patient with latent autoimmune diabetes who developed SPS through the action of subcutaneously injected insulin. A 43-year-old man was diagnosed with diabetes and initially well-controlled with oral hypoglycemic agents but progressed to requiring insulin within 1 year of diagnosis. Two months after the initiation of basal insulin therapy, he presented with abdominal stiffness and painful muscle spasms, involving the lower limbs, which resulted in walking difficulty, and thus, he refused insulin injections thereafter. He had been treated with oral anti-diabetic agents instead of insulin for 10 years until premixed insulin twice daily was started again due to poor diabetes control. Immediately after insulin injection, abdominal muscle rigidity and spasms were noted. When insulin was not administered, frequent episodes of diabetic ketoacidosis occurred. Serum GAD antibody test was positive and there was no positivity for islet antigen-2 antibody. A glucagon stimulation test demonstrated relative insulin deficiency, indicative of latent autoimmune diabetes in adults (LADA). Tolerable muscle rigidity was achieved when the dosage of basal insulin was split into two separate daily injections with lower amounts of units per injection. This case highlights a different form of autoimmune diabetes in SPS. To our knowledge, this is the first report of SPS described shortly after the initiation of insulin therapy that required basal insulin to achieve tolerable muscle symptoms and better glucose control, without the development of diabetic ketoacidosis.

Investigating optimal β-cell-preserving treatment in latent autoimmune diabetes in adults: Results from a 21-month randomized trial

AIMS

To compare outcomes of glucagon-stimulated C-peptide tests (GSCTs) in people with latent autoimmune diabetes in adults (LADA) after a 21-month intervention with either insulin or the dipeptidyl peptidase-4 inhibitor sitagliptin.

RESEARCH DESIGN AND METHODS

We included 64 glutamic acid decarboxylase (GAD) antibody-positive individuals, who were diagnosed with diabetes <3 years before the study, aged 30 to 70 years, and without clinical need for insulin treatment. We stratified participants by age and body mass index (BMI) and evaluated β-cell function by GSCT after a 48-hour temporary withdrawal of study medication.

RESULTS

Age at randomization (mean 53 years), BMI (mean 27 kg/m² ) and metabolic markers were similar between treatment arms. Glycated haemoglobin concentrations during intervention did not differ between arms. Fasting C-peptide concentrations after the intervention were similar, as were stimulated C-peptide levels (0.82 ± 0.63 nmol/L after insulin, 0.82 ± 0.46 nmol/L after sitagliptin; nonsignificant). Autoimmunity in the study population (estimated from GAD antibody titres and positivity/no positivity for zinc transporter 8 and islet antigen 2 antibodies) affected the evolution of the GSCT results significantly, which deteriorated in participants with high but not in those with low autoimmunity. Adjustment using analysis of covariance for the degree of autoimmunity did not alter the findings of no difference between treatment arms.

CONCLUSIONS

β-cell function after intervention was similar in patients with insulin- and sitagliptin-treated LADA, regardless of the strength of autoimmunity. Further, participants with low levels of GAD antibodies did not experience progressive deterioration of β-cell function over a 21-month period. Taken together, these findings could be useful for clinicians' choices of treatment in people with LADA.

Altered T-cell subsets and transcription factors in latent autoimmune diabetes in adults taking sitagliptin, a dipeptidyl peptidase-4 inhibitor: A 1-year open-label randomized controlled trial

AIMS/INTRODUCTION

Dipeptidyl peptidase-4 inhibitor has been proven to improve glycemic control and β-cell function in latent autoimmune diabetes in adults (LADA). The potential immune modulation mechanism is still unknown. Thus, we tested T-lymphocyte subsets and expression of relevant transcription factors in LADA patients with sitagliptin intervention for up to 1-year.

MATERIALS AND METHODS

A total of 40 LADA patients were randomly assigned to sitagliptin and/or insulin treatment (SITA group; n = 20) or insulin alone treatment (CONT group; n = 20). Peripheral blood mononuclear cells were isolated at baseline, 6 months and 12 months. The percentage of T-lymphocyte subsets (T helper 1, T helper 2, T helper 17 and regulatory T cells) tested by flow cytometry, and the messenger ribonucleic acid expression (T box expressed in T cells [T-BET], GATA binding protein 3 [GATA3], forkhead box protein 3 [FOXP3] and related orphan receptor C [RORC]) tested by real-time polymerase chain reaction were determined at baseline, 6 months and 12 months.

RESULTS

The percentage of regulatory T cells in the SITA group was significantly lower than that of the CONT group at baseline. The percentage of T helper 2 cells was higher than that of the CONT group at 6 months and 12 months. At 12 months, the percentage of T helper 17 cells was lower in the SITA group than that of the CONT group. After a 1-year visit, the messenger ribonucleic acid expression levels of T-BET expressed in T cells and RORC in the SITA group were significantly lower than at baseline. Whereas that of RORC in the CONT group were significantly lower than that at baseline.

CONCLUSIONS

The data confirmed that sitagliptin altered the phenotype of T cells and downregulated the expression of T-BET and RORC in LADA patients, and ameliorated glycemic control in LADA patients.

Treatment of Latent Autoimmune Diabetes in Adults: What is Best?

Latent Autoimmune Diabetes in Adults (LADA), although formally classified as Type 1 Diabetes (T1D), very often (at least in Western countries) appear clinically with Type 2 Diabetes (T2D)-like features as overweight and insulin resistance. LADA patients do not need exogenous insulin at the time they are diagnosed with diabetes, but a large percentage will within a few years develop need for such treatment. The decline in beta cell function progresses much faster in LADA than in T2D, presumably because of the ongoing autoimmune assault in LADA, and therefore necessitates insulin therapy much earlier in LADA than in T2D. Despite high prevalence of LADA (about 10% of the total diabetic population in many countries), the treatment of LADA patients is far less elucidated than is the case for T1D and T2D. Finding a treatment strategy for LADA from the time of diagnosis, that can reduce the decline of beta cell function, ensure adequate metabolic control and thereby reduce the risk of diabetic complications is thus an important clinical challenge. Conclusions from the randomized treatment studies so far do not indicate an optimal treatment strategy in LADA. This review aims to give an overview of current practices for the medical treatment of LADA as well as an update on results from recent studies on the treatment of the disease.

Dulaglutide treatment results in effective glycaemic control in latent autoimmune diabetes in adults (LADA): A post-hoc analysis of the AWARD-2, -4 and -5 Trials

AIMS

Patients with a type-2-diabetes (T2D) phenotype positive for glutamic acid decarboxylase antibodies (GADA) represent the majority of cases of latent autoimmune diabetes of the adult (LADA). The GLP-1 receptor agonist dulaglutide, recently introduced for treatment of T2D, has yet to be evaluated in LADA patients. Our primary objective was to evaluate the effect of dulaglutide on glycaemic control (HbA1c) in GADA-positive LADA vs GADA-negative T2D patients.

METHODS

A post-hoc analysis was performed using data from 3 randomized phase 3 trials (AWARD-2,-4,-5; patients with GADA assessment) which were part of the dulaglutide clinical development programme in T2D. LADA patients were identified by GADA ≥5 IU/mL (ELISA). Changes in HbA1c during 12 months of treatment with dulaglutide or comparator were analysed using mixed-effect model repeated measures.

RESULTS

Of 2466 adults tested for GADA (dulaglutide, 1710; glargine, 298; sitagliptin, 294; placebo, 164), 2278 (92.4%) were GADA-negative and 188 (7.6%) were GADA-positive, including 58 GADA-high patients (> 200 IU/mL) and 130 GADA-low patients (≤200 and ≥5 IU/mL). Overall, baseline parameters were comparable between the groups. Dulaglutide resulted in comparable HbA1c reductions in GADA-negative (LS mean change [95%CI], -1.09% [-1.15, -1.03]) and GADA-positive patients (-0.94% [-1.15, -0.72]) at 12 months. HbA1c reductions were numerically, but not statistically, significantly larger in GADA-low patients (-1.02% [-1.26, -0.78]) vs GADA-high patients (-0.72% [-1.21,-0.24]) at 12 months. Similar outcomes were observed at 3 and 6 months.

CONCLUSIONS

These data are the first to indicate that dulaglutide was effective in reducing HbA1c in LADA patients.

Adult-onset autoimmune diabetes: current knowledge and implications for management

Adult-onset autoimmune diabetes is a heterogeneous disease that is characterized by a reduced genetic load, a less intensive autoimmune process and a mild metabolic decompensation at onset compared with young-onset type 1 diabetes mellitus (T1DM). The majority of patients with adult-onset autoimmune diabetes do not require insulin treatment for at least 6 months after diagnosis. Such patients are defined as having latent autoimmune diabetes in adults (LADA), which is distinct from classic adult-onset T1DM. The extensive heterogeneity of adult-onset autoimmune diabetes is apparent beyond the distinction between classic adult-onset T1DM and LADA. LADA is characterized by genetic, phenotypic and humoral heterogeneity, encompassing different degrees of insulin resistance and autoimmunity; this heterogeneity is probably a result of different pathological mechanisms, which have implications for treatment. The existence of heterogeneous phenotypes in LADA makes it difficult to establish an a priori treatment algorithm, and therefore, a personalized medicine approach is required. In this Review, we discuss the current understanding and gaps in knowledge regarding the pathophysiology and clinical features of adult-onset autoimmune diabetes and highlight the similarities and differences with classic T1DM and type 2 diabetes mellitus.

Metabolite Profiling of LADA Challenges the View of a Metabolically Distinct Subtype

Latent autoimmune diabetes in adults (LADA) usually refers to GAD65 autoantibodies (GADAb)-positive diabetes with onset after 35 years of age and no insulin treatment within the first 6 months after diagnosis. However, it is not always easy to distinguish LADA from type 1 or type 2 diabetes. In this study, we examined whether metabolite profiling could help to distinguish LADA (n = 50) from type 1 diabetes (n = 50) and type 2 diabetes (n = 50). Of 123 identified metabolites, 99 differed between the diabetes types. However, no unique metabolite profile could be identified for any of the types. Instead, the metabolome varied along a C-peptide-driven continuum from type 1 diabetes via LADA to type 2 diabetes. LADA was more similar to type 2 diabetes than to type 1 diabetes. In a principal component analysis, LADA patients overlapping with type 1 diabetes progressed faster to insulin therapy than those overlapping with type 2 diabetes. In conclusion, we could not find any unique metabolite profile distinguishing LADA from type 1 and type 2 diabetes. Rather, LADA was metabolically an intermediate of type 1 and type 2 diabetes, with those patients closer to the former showing a faster progression to insulin therapy than those closer to the latter.

Saxagliptin improves glycaemic control and C-peptide secretion in latent autoimmune diabetes in adults (LADA)

BACKGROUND

To assess the efficacy and tolerability of saxagliptin and C-peptide secretion in patients with diagnosed type 2 diabetes classified as glutamic acid decarboxylase antibody (GADA)-positive or GADA-negative.

METHODS

Post hoc analysis of data pooled from five randomized, placebo-controlled, 24-week phase 3 studies (n = 2709) was conducted. We evaluated mean change from baseline at week 24 in HbA1c , fasting plasma glucose, postprandial plasma glucose, fasting and postprandial C-peptide, and HOMA2-%β and the proportion of patients achieving HbA1c  < 7% (53 mmol/mol) at week 24.

RESULTS

Saxagliptin produced greater adjusted mean reductions from baseline in HbA1c versus placebo for GADA-negative [difference vs placebo (95% CI), -0.62% (-0.71% to -0.54%); -6.8 mmol/mol (-7.8, -5.9)] and GADA-positive patients [-0.64% (-1.01% to -0.27%); -7.0 mmol/mol (-11.0, -3.0)]. Consistently, saxagliptin produced a greater reduction from baseline in fasting plasma glucose and postprandial plasma glucose versus placebo in GADA-positive versus GADA-negative patients, and more patients achieved HbA1c  < 7% (53 mmol/mol) with saxagliptin versus placebo in both GADA-negative and GADA-positive patients. Saxagliptin increased β-cell function as assessed by HOMA2-%β and postprandial C-peptide area under the curve from baseline in patients in both GADA-positive and GADA-negative patients. Adverse events and hypoglycaemic events were similar across treatment groups and GADA categories.

CONCLUSION

Saxagliptin was effective in lowering blood glucose levels and generally well tolerated in GADA-positive patients. Interestingly, saxagliptin appears to improve β-cell function in these patients, although a longer treatment duration may be needed to confirm this finding.