Cambridge hybrid closed-loop algorithm in children and adolescents with type 1 diabetes: a multicentre 6-month randomised controlled trial

BACKGROUND

Closed-loop insulin delivery systems have the potential to address suboptimal glucose control in children and adolescents with type 1 diabetes. We compared safety and efficacy of the Cambridge hybrid closed-loop algorithm with usual care over 6 months in this population.

METHODS

In a multicentre, multinational, parallel randomised controlled trial, participants aged 6-18 years using insulin pump therapy were recruited at seven UK and five US paediatric diabetes centres. Key inclusion criteria were diagnosis of type 1 diabetes for at least 12 months, insulin pump therapy for at least 3 months, and screening HbA1c levels between 53 and 86 mmol/mol (7·0-10·0%). Using block randomisation and central randomisation software, we randomly assigned participants to either closed-loop insulin delivery (closed-loop group) or to usual care with insulin pump therapy (control group) for 6 months. Randomisation was stratified at each centre by local baseline HbA1c. The Cambridge closed-loop algorithm running on a smartphone was used with either (1) a modified Medtronic 640G pump, Medtronic Guardian 3 sensor, and Medtronic prototype phone enclosure (FlorenceM configuration), or (2) a Sooil Dana RS pump and Dexcom G6 sensor (CamAPS FX configuration). The primary endpoint was change in HbA1c at 6 months combining data from both configurations. The primary analysis was done in all randomised patients (intention to treat). Trial registration ClinicalTrials.gov, NCT02925299.

FINDINGS

Of 147 people initially screened, 133 participants (mean age 13·0 years [SD 2·8]; 57% female, 43% male) were randomly assigned to either the closed-loop group (n=65) or the control group (n=68). Mean baseline HbA1c was 8·2% (SD 0·7) in the closed-loop group and 8·3% (0·7) in the control group. At 6 months, HbA1c was lower in the closed-loop group than in the control group (between-group difference -3·5 mmol/mol (95% CI -6·5 to -0·5 [-0·32 percentage points, -0·59 to -0·04]; p=0·023). Closed-loop usage was low with FlorenceM due to failing phone enclosures (median 40% [IQR 26-53]), but consistently high with CamAPS FX (93% [88-96]), impacting efficacy. A total of 155 adverse events occurred after randomisation (67 in the closed-loop group, 88 in the control group), including seven severe hypoglycaemia events (four in the closed-loop group, three in the control group), two diabetic ketoacidosis events (both in the closed-loop group), and two non-treatment-related serious adverse events. There were 23 reportable hyperglycaemia events (11 in the closed-loop group, 12 in the control group), which did not meet criteria for diabetic ketoacidosis.

INTERPRETATION

The Cambridge hybrid closed-loop algorithm had an acceptable safety profile, and improved glycaemic control in children and adolescents with type 1 diabetes. To ensure optimal efficacy of the closed-loop system, usage needs to be consistently high, as demonstrated with CamAPS FX.

FUNDING

National Institute of Diabetes and Digestive and Kidney Diseases.

Efficacy and safety of canagliflozin when used in conjunction with incretin-mimetic therapy in patients with type 2 diabetes

AIMS

To assess the efficacy and safety of canagliflozin, a sodium glucose co-transporter 2 (SGLT2) inhibitor, in patients with type 2 diabetes enrolled in the CANagliflozin cardioVascular Assessment Study (CANVAS) who were on an incretin mimetic [dipeptidyl peptidase-4 (DPP-4) inhibitor or glucagon-like peptide-1 (GLP-1) receptor agonist].

METHODS

CANVAS is a double-blind, placebo-controlled study that randomized participants to canagliflozin 100 or 300 mg or placebo added to routine therapy. The present post hoc analysis assessed the efficacy and safety of canagliflozin 100 and 300 mg compared with placebo in subsets of patients from CANVAS who were taking background DPP-4 inhibitors or GLP-1 receptor agonists with or without other antihyperglycaemic agents at week 18.

RESULTS

Of the 4330 patients in CANVAS, 316 were taking DPP-4 inhibitors and 95 were taking GLP-1 receptor agonists. At 18 weeks, canagliflozin 100 and 300 mg provided larger placebo-subtracted reductions in glycated haemoglobin (HbA1c) in patients taking DPP-4 inhibitors [-0.56% (95% confidence interval [CI]: -0.77, -0.35), and -0.75% (95% CI: -0.95, -0.54), respectively] and GLP-1 receptor agonists [-1.00% (95% CI: -1.35, -0.65), and -1.06% (95% CI: -1.43, -0.69), respectively]. Body weight and blood pressure (BP) reductions were seen with canagliflozin versus placebo in both subsets. Higher incidences of genital mycotic infections and osmotic diuresis-related adverse events (AEs) were seen with canagliflozin compared with placebo. The incidence of hypoglycaemia was numerically higher with canagliflozin versus placebo; nearly all events occurred in patients on background insulin or insulin secretagogues.

CONCLUSIONS

In patients on background incretin mimetics, canagliflozin improved HbA1c, body weight and BP, with an increased incidence of AEs related to SGLT2 inhibition.

Once weekly exenatide: efficacy, tolerability and place in therapy

Exenatide once weekly is the first glucose-lowering agent available to patients with type 2 diabetes mellitus (T2DM) which is administered once per week. This long-acting formulation contains the same active ingredient as exenatide twice daily, except that the exenatide is encapsulated in dissolvable microspheres. Following subcutaneous injection, exenatide once weekly microspheres remain in place under the skin and slowly degrade, releasing active exenatide continuously into circulation. In randomized clinical trials, exenatide once weekly was associated with significant glycaemic improvement and moderate weight loss in patients with T2DM when administered as monotherapy or in combination with a variety of oral antidiabetic agents. Exenatide once weekly also lowered blood glucose more effectively than titrated basal insulin in patients on metformin or metformin plus sulphonylurea background therapy. Gastrointestinal side effects (nausea, vomiting and diarrhoea) were the most common tolerability issues associated with exenatide once weekly administration, but they occurred at lower rates than in patients on other glucagon-like peptide receptor agonists (i.e., exenatide twice daily or liraglutide). Issues regarding the place of exenatide once weekly in T2DM pharmacotherapy are discussed.

DURATION-2: efficacy and safety of switching from maximum daily sitagliptin or pioglitazone to once-weekly exenatide

AIMS

In the initial 26-week, double-blind, double-dummy assessment period of the DURATION-2 trial in patients with Type 2 diabetes on metformin, the once-weekly glucagon-like peptide 1 (GLP-1) receptor agonist exenatide once-weekly resulted in greater HbA(1c) improvement and weight reduction compared with maximum approved daily doses of sitagliptin or pioglitazone. This subsequent, 26-week, open-label, uncontrolled assessment period evaluated the safety and efficacy of (i) continued exenatide once-weekly treatment and (ii) switching from sitagliptin or pioglitazone to exenatide once-weekly.

METHODS

Randomised oral medications were discontinued and all patients received exenatide once-weekly. Of the 364 patients [original baseline HbA(1c) 8.5 ± 1.1% (70 mmol/mol), fasting plasma glucose 9.0 ± 2.5 mmol/l, weight 88 ± 20 kg) who continued into the open-label period, 319 patients (88%) completed 52 weeks.

RESULTS

Evaluable patients who received only exenatide once-weekly demonstrated significant 52-week improvements (least square mean ± se) in HbA(1c) (-1.6 ± 0.1%), fasting plasma glucose (-1.8 ± 0.3 mmol/l) and weight (-1.8 ± 0.5 kg). Evaluable patients who switched from sitagliptin to exenatide once-weekly demonstrated significant incremental improvements in HbA(1c) (-0.3 ± 0.1%), fasting plasma glucose (-0.7 ± 0.2 mmol/l) and weight (-1.1 ± 0.3 kg). Patients who switched from pioglitazone to exenatide once-weekly maintained HbA(1c) and fasting plasma glucose improvements (week 52: -1.6 ± 0.1%, -1.7 ± 0.3 mmol/l), with significant weight reduction (-3.0 ± 0.3 kg). Exenatide once-weekly was generally well tolerated and adverse events were predominantly mild or moderate in intensity. Nausea was the most frequent adverse event in this assessment period (intent-to-treat: exenatide once-weekly-only 5%; sitagliptin→exenatide once-weekly 11%; pioglitazone→exenatide once-weekly 10%). No major hypoglycaemia was observed.

CONCLUSIONS

Patients who switched to once-weekly exenatide from daily sitagliptin or pioglitazone had improved or sustained glycaemic control, with weight loss.

Development of a preliminary diabetes dietary satisfaction and outcomes measure for patients with type 2 diabetes

Adopting dietary lifestyle changes for diabetes management is often difficult for patients; yet the health-related quality of life (HRQOL) outcomes of dietary management for the patient are not extensively developed in the HRQOL assessments now widely used in diabetes research. This study developed a preliminary instrument, the diabetes dietary satisfaction and outcomes measure, to assess outcomes of individuals' experiences in following a meal plan for the treatment of type 2 diabetes. A theoretical framework and preliminary focus group data guided the design of a 47-item questionnaire, administered to 239 patients with type 2 diabetes. Medical file data was obtained on 180 of these patients. Fifty-four percent of respondents were women, with mean age of 64 +/- 12 years and diabetes duration of 10 +/- 8 years. Scores for the satisfaction and other outcome measures discriminated between patient groups by age, gender, medication use, depression diagnosis, meal plan status, and employment status. Significant correlations also occurred with diet adherence, number of co-morbidities, and glycemic control as measured by glycolated hemoglobin (HbA1c). Future research with additional patient samples is needed to refine the measure for use in diabetes education programs.

Imipramine effect on hypothalamic-pituitary-adrenal axis response to hypoglycemia

Six control subjects underwent an insulin tolerance test before and after the administration of therapeutic doses of imipramine hydrochloride for 10 days to investigate effects of tricyclic antidepressants on hypothalamic-pituitary-adrenal axis response to hypoglycemia. The mean steady-state tricyclic blood level was 141 (SD = 66) ng/ml. Baseline levels of glucose, cortisol, and adrenocorticotropic hormone (ACTH) were not affected by the administration of imipramine. After administration of imipramine for 10 days, subjects uniformly had a significantly lower glucose nadir than before its administration (before imipramine: mean = 32 mg/dl; SD = 5; after imipramine: mean = 24 mg/dl; SD = 6). There was no difference in ACTH or cortisol response before and after the administration of imipramine. These findings suggest that imipramine hydrochloride increases sensitivity to the hypoglycemic effects of insulin, but does not alter the counterregulatory response of ACTH and cortisol.

Age-related changes in the circadian rhythm of plasma cortisol in man

We studied the effect of age on the circadian rhythm of plasma cortisol in 34 normal subjects, aged 18-75 yr. Blood was sampled at 20-min intervals beginning at 2000 h, and the data were analyzed using the PULSAR program and the cosinor method. There was a negative correlation between age and the time of the maximum cortisol concentration (r = -0.548; P = 0.001), the time of the nadir cortisol concentration (r = -0.543; P = 0.001), and the acrophase (r = 0.528; P = 0.001). When the subjects were divided into those 39 yr of age and younger and 40 yr of age and older, the times of the cortisol nadir, maximum, and acrophase were significantly earlier in the older group. The interval between the nadir and peak cortisol levels was not significantly different, consistent with an age-related phase advance of the cortisol circadian rhythm. Quantitative indices of adrenal function, including the 24-h mean cortisol concentration and the number of cortisol peaks as well as their amplitude and duration, were not different in the two groups. There was a significant negative correlation between age and customary bedtime (r = -0.686; P = 0.001) that may explain, in part, the phase advance in the older subjects. This observation strengthens the evidence that sleep onset is a major factor contributing to synchronization of the cortisol rhythm. Alternative explanations are that age-related changes in the control of hormonal and other rhythms have important influences on sleep and activity schedules, or that sleep and cortisol variables do not influence each other, but are both the final expression of some central change.