Semaglutide Treatment for Hyperglycaemia After Renal Transplantation

Introduction:

In renal transplant recipients, hyperglycaemia develops frequently in the immediate period after renal transplantation. Insulin is the primary choice of treatment but carries the adherent risk of hypoglycaemia and weight gain. Tablet semaglutide is a potent glucose-lowering agent that can reduce weight and the incidence of hypoglycaemia. It also has the ability to delay progression of chronic kidney disease (CKD). However, semaglutide is not recommended for renal transplant recipients, as safety and efficacy has yet to be established. The aim of this study is to prove that semaglutide is safe in renal transplant recipients and potentially just as effective as insulin-treatment. We expect that semaglutide can reduce daily insulin-usage and, for a large number of patients, even completely replace insulin as treatment, thereby avoiding the harmful side-effects of this drug.

Objectives:

The primary aim is to establish if tablet semaglutide (Rybelsus) compared with placebo, both as add-on to standard-of-care, is non-inferior in regulating plasma glucose in patients with hyperglycaemia in the immediate weeks after renal transplantation.

Secondary objectives aim to evaluate the effect of tablet semaglutide on renal allograft function, weight, daily use of insulin and safety parameters (plasma semaglutide concentration, gastrointestinal side effects, dose of immunosuppressants).

Background:

Patients developing end-stage renal disease require renal replacement therapy by either haemodialysis, peritoneal dialysis, or renal transplantation. Renal transplantation is considered the best option for renal replacement therapy in terms of both quality of life and cost-effectiveness. However, in the immediate weeks after renal transplantation hyperglycaemia can develop - a condition termed post-transplant hyperglycaemia that is defined by a plasma glucose ≥ 7.0 mmol/L, or 2-h plasma glucose ≥ 11.1 mmol/L after an oral glucose tolerance test. A cohort study of renal transplant recipients (n=319), without pre-transplant diabetes, found that 66% required glucose-lowering treatment when discharge after renal transplantation. The primary reason for hyperglycaemia is high-dose prednisone in combination with surgical stress and other immunosuppressants. The condition post-transplant diabetes mellitus can be diagnosed once the patient is on stable and minimum immune suppressive treatment.

Current guidelines recommend that oral glucose-lowering agents are used for mild hyperglycaemia and insulin for more pronounced hyperglycaemia. Only oral sulfonylureas and dipeptidyl peptidase-4 (DPP-4) inhibitors are permitted for use shortly after renal transplantation. However, sulfonylureas, as with insulin, carry the risk of hypoglycaemia, and DPP-4 inhibitors have only a modest glucose-lowering effect. Therefor insulin treatment is primarily used with the adherent risk of hypoglycaemia, weight gain and the discomfort of daily subcutaneous injections.

Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) are relatively new glucose-lowering agents that effective lowers plasma glucose by enhancing glucose-dependent insulin secretion, regulating postprandial glucagon, and reducing food intake. GLP-1 RAs are not tested prospectively in the renal transplanted population and only two small and retrospective studies have evaluated the safety and efficacy of GLP-1RAs. Here treatment with a GLP-1 RA was associated with a reduced daily insulin dose and lower incidence of hypoglycaemia. Importantly, renal allograft function remained stable with no required adjustment in immunosuppression. In the general diabetes population, the SUSTAIN-6 trial and the PIONEER-6 trial both found that semaglutide yielded a reduction in haemoglobin A1c (HbA1c) and weight. In addition, the SUSTAIN-6 trial found a delay in progression of renal impairment and a lower risk of cardiovascular mortality.

Semaglutide is metabolised by proteolytic cleavage and alterations in renal function are not expected to influence pharmacokinetics. This notion is supported by studies of patients treated with semaglutide where various degrees of renal impairment, including end-stage renal disease, did not influence pharmacokinetics of semaglutide.

Several concerns remain before semaglutide can be used more widely in renal transplanted population. Semaglutide can induce gastrointestinal symptoms (nausea, vomiting, and diarrhoea) that carries a risk of dehydration and gastric paresis that can cause acute kidney injury. Alterations in gastric emptying could change the uptake of immunosuppressive drugs, which in turn can affect renal allograft function.

Study hypothesis:

The investigators expect in the semaglutide group compared to the placebo group to show:

• Similar mean sensor glucose (mmol/L)
• Similar time-in-range (3.9-10.0 mmol/L)
• Reduction in glucose variability
• Reduction in the incidence of hypoglycaemia
• Reduction in daily dose of insulin
• Reduction in weight
• Unaffected renal function of the transplanted kidney
• Unchanged uptake of immunosuppressive medication

Methods and assessments:

Participants diagnosed with post-transplant hyperglycaemia, 10 to 40 days post-transplant, or type 2 diabetes will be randomised 1:1 to either 14 weeks of tablet semaglutide or placebo both as add-on to standard glucose-lowering therapy. Participants will be in weekly contact with the clinic during the first five weeks and with two to four weeks intervals during the remaining study period (Appendix 1). During the trial, each patient will be monitored according to blood laboratory values and with safety assessed at every visit by a nephrologist. Pre-prandial plasma glucose will be measured morning and evening to adjust glucose-lowering therapy in consultation with an endocrinologist. Blinded CGM will be used for 10-14 days from baseline and at weeks 5, 9, and 13.

Questionnaires on gastrointestinal side effects:

Questionnaires on gastrointestinal side effects will be evaluated using the Gastrointestinal symptom rating scale (GSRS). The 15 items in the GSRS questionnaire combine into five symptom clusters: Reflux, Abdominal pain, Indigestion, Diarrhoea and Constipation. The reliability and validity of the GSRS are well-documented, and norm values for a general population are available.

Continuous glucose monitoring:

A blinded professional Free Style Libre iQ or Dexcom G6/G7 will be used. The sensor is placed on the back of the upper arm and will record interstitial sensor glucose readings every 5-15 min for 10-14 days. The sensor is water-resistant, and no limitations on physical activity exist. CGM data are double blinded. A minium of three CGM-days must be completed for each CGM-period for inclusion in the data analysis.

Blood samples:

Blood samples will be taken at screening (visit 2) and weeks 2, 3, 4, 5, 7, 9, 12, 13, 14 (end of trial). The following laboratory variables will be measured:

• Haemoglobin, leukocytes, platelets
• ALAT, amylase
• Creatinine, urea, sodium, potassium
• C-reactive protein
• Ionised calcium, total phosphate
• Plasma glucose
• Blood cyclosporine (µg/L) and blood tacrolimus (µg/L) At week 1, 5, 9 and 14 following blood samples will be taken
• LDL, HDL, triglycerides, total cholesterol, HbA1c and intact parathyroid hormone

Trial medication:

At baseline participants will initiate treatment with 3mg of oral semaglutide dosing from weeks 1 to 4. Depending on tolerability the dose will increase to 7 mg daily from weeks 5 to 8 and 14 mg from week 9. Trial medication will be dispensed to subjects for the first time immediately after randomisation and adjusted week 5 and week 9.

Glucose-lowering therapy during the study period:

Semaglutide or placebo will be added on top of standard-of-care treatment. Standard-of-care is generally insulin-based treatment, but sulfonylurea may be used. DPP-4 inhibitors are contraindicated during semaglutide treatment. Standard-of-care is not well defined in the renal transplanted population immediately after transplantation. The investigators suggest the following approach:

Study initiation:

Oral semaglutide 3mg or placebo plus standard-of-care defined as:

• If fasting plasma glucose is 7.0-8.4 mmol/L then administration of 0.1 IE/kg (Insulin glargin)
• If fasting plasma glucose is 8.5-9.4 mmol/L then administration of 0.15 IE/kg (Insulin glargin)
• If fasting plasma glucose is 9.5-10.4 mmol/L then administration of 0.25 IE/kg (Insulin glargin)
• If OGTT ≥ 11.0 mmol/L then administration of 0.1 IE/kg (Insulin glargin)

During the study:

Glycaemic monitoring will be performed using pre-prandial plasma glucose (finger prick) in the morning and evening. Based on these measures, and in consultant with an endocrinologist, the glucose-lowering therapy will be adjusted. The glycaemic target is 4-7 mmol/L morning and 6-10 mmol/L evening (both pre-prandial). When increasing semaglutide long-acting insulin is recommended adjusted at the following due to modest effect of semaglutide within the first week. Add-on therapy with sliding scale of fast-acting insulin or sulfonylureas may be added at the discretion of the endocrinologist. At study completion semaglutide and placebo are discontinued and participants returne to standard-of-care.

Reduction in glucose-lowering therapy should be initiated if morning plasma glucose (pre-prandal) < 4 mmol/L 2 out of 3 days or evening plasma glucose (pre-prandial) < 6 mmol/l 2 out of 3 days or if symptomatic hypoglycaemia occurs. Reduction can be performed by the endocrinologist or by the participant. In the study protocol the investigatorsrecommend the following steps but adjustments are at the discretion of the endocrinologist:

Step 1) Patients in Insulin glargine treatment should be reduced by following regime: Firstly reduce by 4 IU of long-acting insulin. If plasma glucose continuously below target reduce by another 4 IU.

Step 2) If plasma glucose is below target and Insulin glargine is < 8 IU, insulin glargine treatment is stopped completely. Secondly, sulfonylurea is stopped.

Step 3) If insulin glargin/sulfonylurea treatment is discontinued and further reductions is required semaglutide is dose reduced from 14mg to 7mg, then from 7mg to 3mg and then from 3mg to 0mg (patient is still required to complete the full study period if glucose-lowering therapy is discontinued).

Statistical evaluation:

The primary endpoint and the secondary endpoints will be reported based on a per protocol analysis with a compliance >80% of the prescribed trial medication. Some secondary endpoints (safety parameters) will be reported based on the intention-to-treat analysis, thus including all randomized participants.

Justification of sample size/power calculation:

The investigators will test the hypothesis if treatment with semaglutide is non-inferior to standard-of-care, with mean sensor glucose (mmol/L) as the primary endpoint in a homogeneous group of renal-transplanted patients with hyperglycaemia. The trial is powered for the primary endpoint, change in mean sensor glucose to assess non-inferiority. The power calculation is based on CGM data from 30 haemodialysis patients with type 2 diabetes that resembles renal transplant recipients with hyperglycaemia as both groups are primarily treated with insulin as standard-of-care. The group of haemodialysis patients are compared with 36 patients with type 2 diabetes and eGFR above 60ml/min/1.73m2 where the majority was treated with without insulin and with antidiabetic medication such as semaglutide.

Sample size calculation is based on a two-sample one-sided t-test with non-inferiority margin of 2mmol/L, expected difference of 0.9 mmol/L, standard deviation of 1.8, power of 90 % and significance level of 5%. This resulted in 47 patients needed in each group, accounting for possible dropout, 10 % expected, a final sample size of 52 patients in each group is needed.

Effect analysis:

Distribution and changes to endpoints will be described and expressed as means± standard error of the mean or median (range or interquartile range) for continues endpoints and frequencies and percentages for categorical endpoints. Comparison of continues outcomes between groups are done by two-sample t-tests if variables are normally distributed, otherwise Wilcoxon sum-rank test is used instead. Comparison of categorical outcomes are done by chi-squared test or fisher's exact test. Repeated measures are compared by mixed regression models. P-values of less than 5 % will be considered statistically significant.

Analysis of safety parameters:

The safety analysis will be performed based on all randomised subjects. A quantitative description of serious and non-serious adverse events will be presented. A qualitative presentation of serious adverse event will be provided.

Feasibility:

Participants will be recruited from Rigshospitalet, Copenhagen; Aarhus, Aarhus University Hospital and Odense, Odense University hospital. Approximately 250 renal transplants are performed in Denmark and we expect with 20-40% will have post-transplant hyperglycaemia 10-15 days after transplantation equivalent to approximately 40 to 80 patients per year. With an aim of 104 included participants the study is expected to last three years.

Ethical considerations:

Semaglutide is well tested in the general diabetes population and not affected by variations in renal function. Participants will be thoroughly monitored throughout the study period to ensure safety. When the trial has ended, concluded and results have been published, participants will be informed of the results of the trial.

The study is registered at ClinicalTrials.gov prior to initiation and the protocol is compliant with the principles of Helsinki Declaration II. The trial will be conducted in compliance with the Good Clinical Practice (GCP) guidelines. A local GCP monitor from the GCP unit at Copenhagen University Hospital, Frederiksberg Hospital will be allocated to the study.