Developing, Planning and Conducting an Interim Analysis: Lessons From the DEVOTE Cardiovascular Outcomes Trial (Trial Comparing Cardiovascular Safety of Insulin Degludec Versus Insulin Glargine in Patients With Type 2 Diabetes at High Risk of Cardiovascular Events).

BACKGROUND: In 2013, a randomized, double-blind, active comparator-controlled, event-driven cardiovascular outcomes trial (DEVOTE) was initiated to compare the cardiovascular safety of insulin degludec (degludec) versus insulin glargine 100 units/mL (glargine U100) in patients with type 2 diabetes at high risk of cardiovascular events. The FDA agreed that an interim analysis could form the basis for an early regulatory approval. We report here the operational model developed to support the DEVOTE interim analysis and the results. METHODS: The interim analysis model was designed to reduce the risk of any confidentiality breaches. The Data Access Management Plan comprehensively described the interim analysis operational processes and procedures to maintain the integrity of the ongoing trial while the interim analysis was conducted, submitted, and acted upon by the FDA, and also until completion of the full trial. Most importantly, those who were unblinded to the interim results were limited to a team of 14 members. RESULTS: A total of 150 first major adverse cardiovascular events were recorded at cut-off for the interim analysis. The estimated hazard ratio was 0.92 (95% CI 0.67, 1.27) and non-inferiority to glargine U100 was confirmed as the upper bound of the confidence interval was below 1.8, as prespecified. Based on these results, the FDA approved the use of degludec and degludec/insulin aspart (IDegAsp) in the United States in 2015 before trial completion. CONCLUSIONS: The DEVOTE interim analysis succeeded as a model by which to conduct an interim analysis and submit confidential data for regulatory review and action while continuing the trial to address a primary hypothesis.

Semaglutide, reduction in glycated haemoglobin and the risk of diabetic retinopathy.

AIMS: To evaluate diabetic retinopathy (DR) data from across the SUSTAIN clinical trial programme. MATERIALS AND METHODS: The SUSTAIN clinical trial programme evaluated the efficacy and safety of semaglutide, a glucagon-like peptide-1 analogue, for the treatment of type 2 diabetes (T2D). In SUSTAIN 6, a 2-year, pre-approval cardiovascular outcomes trial, semaglutide was associated with a significant increase in the risk of DR complications (DRC) vs placebo. DR data from across the SUSTAIN trials were evaluated, and post hoc analyses of the SUSTAIN 6 data were conducted. These included subgroup analyses to identify at-risk patients and a mediation analysis with initial change in glycated haemoglobin (HbA1c; percentage-points at week 16) as a covariate, to examine the role of the magnitude of reduction in HbA1c as an intermediate factor affecting risk of DRC. RESULTS: There was no imbalance in DR adverse events across the SUSTAIN 1 to 5 and Japanese trials. The majority of the effect with semaglutide vs placebo in SUSTAIN 6 may be attributed to the magnitude and rapidity of HbA1c reduction during the first 16 weeks of treatment in patients who had pre-existing DR and poor glycaemic control at baseline, and who were treated with insulin. CONCLUSIONS: Early worsening of DR is a known phenomenon associated with the rapidity and magnitude of improvement in glycaemic control with insulin; the DRC findings in SUSTAIN 6 are consistent with this. Guidance regarding the early worsening of DR is recommended with insulin. Similar recommendations may be appropriate for semaglutide.

Human Achilles tendon glycation and function in diabetes.

Diabetic patients have an increased risk of foot ulcers, and glycation of collagen may increase tissue stiffness. We hypothesized that the level of glycemic control (glycation) may affect Achilles tendon stiffness, which can influence gait pattern. We therefore investigated the relationship between collagen glycation, Achilles tendon stiffness parameters, and plantar pressure in poorly (n = 22) and well (n = 22) controlled diabetic patients, including healthy age-matched (45-70 yr) controls (n = 11). There were no differences in any of the outcome parameters (collagen cross-linking or tendon stiffness) between patients with well-controlled and poorly controlled diabetes. The overall effect of diabetes was explored by collapsing the diabetes groups (DB) compared with the controls. Skin collagen cross-linking lysylpyridinoline, hydroxylysylpyridinoline (136%, 80%, P < 0.01) and pentosidine concentrations (55%, P < 0.05) were markedly greater in DB. Furthermore, Achilles tendon material stiffness was higher in DB (54%, P < 0.01). Notably, DB also demonstrated higher forefoot/rearfoot peak-plantar-pressure ratio (33%, P < 0.01). Overall, Achilles tendon material stiffness and skin connective tissue cross-linking were greater in diabetic patients compared with controls. The higher foot pressure indicates that material stiffness of tendon and other tissue (e.g., skin and joint capsule) may influence foot gait. The difference in foot pressure distribution may contribute to the development of foot ulcers in diabetic patients.

Early osteoarthritis and microdialysis: a novel in vivo approach for measurements of biochemical markers in the perisynovium and intraarticularly.

The microdialysis technique was evaluated as a possible method to obtain local measurements of biochemical markers from knee joints with degenerative changes. Seven patients scheduled for arthroscopy of the knee due to minor to moderate degenerative changes had microdialysis catheters inserted under ultrasonographic guidance, intraarticularly and in the synovium-close tissue. Catheters were perfused at a rate of 2 µl/min for approximately 100 min with a Ringer solution containing radioactively labeled glucose, and the positions of the catheters were later visualized during arthroscopy. All intraarticular catheters and 6/7 subsynovial catheters were positioned correctly. Relative recovery (RR) was intraarticularly 0.64 ± 0.02 (mean ± SEM) and synovium-close 0.54 ± 0.06. Mean values of cartilage oligomeric matrix protein (COMP), aggrecan and glucosyl-galactosyl-pyridinoline in the intraarticular dialysates were 18.1 ± 7.0 U/l, 243.6 ± 108.6 ng/ml and 108.0 ± 29.0 pmol/ml, respectively. COMP and glucosyl-galactosyl-pyridinoline concentrations were significantly higher intraarticularly compared to perisynovial tissue (P < 0.05), whereas for aggrecan, no significant difference was found (P = 0.06). The microdialysis method can be used for intraarticular and subsynovial determination of metabolites in human knees at these sites. The present methodology displays a potential for future studies of simultaneous biochemical changes within and around joints.

Prostaglandin synthesis can be inhibited locally by infusion of NSAIDS through microdialysis catheters in human skeletal muscle.

Prostaglandins are known to be involved in the regulation of local blood flow within human skeletal muscles during exercise, and the concentration of prostaglandins increases locally and systemically in response to exercise. The systemic release of prostaglandins can be inhibited by oral intake of nonsteroidal anti-inflammatory drugs (NSAIDs). However, to study the local role of prostaglandins, the formation of prostaglandins within the tissue must be controlled. Microdialysis enables determination of local concentrations of water-soluble substances within the tissue. In the present study, the microdialysis method was used to infuse NSAIDs locally into human skeletal muscles producing a local block of prostaglandin formation. In addition, the graded blockade at various distances from the infusion site within the muscle during rest, exercise and recovery was determined. Microdialysis was performed in thigh muscles (vastus lateralis muscle) in six healthy men. One of the microdialysis catheters was used to block prostaglandin synthesis by infusion of the NSAID indomethacin. Additional catheters were placed 1 and 4 cm away from the infusion and in the contralateral leg (working control). Following 2 h of rest, the subjects performed 200 maximal eccentric contractions with each leg followed by 3 h of rest. The study revealed that infusion of NSAID reduced local prostaglandin E(2) concentration by approximately 30-50% (4 cm away from the infusion) and 85% (1 cm away from the infusion) compared with the contralateral (unblocked) thigh muscle. In conclusion, the present study shows that infusion of NSAIDs into human muscle via microdialysis catheters results in a graded blockade of prostaglandin synthesis.