Impact of Disease Duration on the Effects of Pramlintide in Type 1 Diabetes: A Post Hoc Analysis of Three Clinical Trials.

INTRODUCTION: Adjunctive mealtime use of the amylin analog pramlintide improves postprandial hyperglycemia in patients with type 1 diabetes. This post hoc analysis of three randomized trials evaluated whether disease duration affected responses to pramlintide. METHODS: Patients received mealtime pramlintide 30 or 60 µg (n = 714) or placebo (n = 537) as an adjunct to insulin and were stratified into tertiles by diabetes duration at baseline. Efficacy and safety end points were assessed at week 26 using analysis of covariance and logistic regression models. RESULTS: Disease durations for tertiles 1, 2, and 3 were 6.7, 16.5, and 29.9 years, respectively. In all tertiles, pramlintide resulted in greater reductions in glycated hemoglobin (HbA1c) and weight than placebo, with greater weight reductions and insulin sparing in tertiles 2 and 3. Insulin dose and weight increased in the placebo group in all tertiles. Baseline HbA1c was a predictor of HbA1c lowering in both treatment groups (P < 0.0001); higher daily insulin predicted a smaller percent increase in insulin dose for placebo (P = 0.01); and higher body weight predicted greater weight loss in both pramlintide- and placebo-treated patients (P < 0.05). Event rates for severe hypoglycemia were similar for pramlintide and placebo and increased with longer duration of diabetes for both groups. Nausea with pramlintide increased with longer disease duration. CONCLUSION: Mealtime pramlintide resulted in greater reductions in HbA1c than placebo, regardless of diabetes duration at baseline. Longer disease duration appeared to augment insulin sparing and weight loss with pramlintide, with a potential for increased incidence of hypoglycemia and nausea. FUNDING: The design and conduct of the study were supported by Amylin Pharmaceuticals, San Diego, CA, USA.

Five-year efficacy and safety data of exenatide once weekly: long-term results from the DURATION-1 randomized clinical trial.

OBJECTIVE: To evaluate the 5-year efficacy and safety of once weekly exenatide. PATIENTS AND METHODS: The Diabetes Therapy Utilization: Researching Changes in A1C, Weight and Other Factors Through Intervention with Exenatide Once Weekly (DURATION-1) randomized clinical trial consisted of a 30-week controlled phase (2 mg of exenatide once weekly vs 10 µg of exenatide twice daily) with an open-ended uncontrolled extension (once weekly exenatide only) in patients with type 2 diabetes mellitus on background glucose-lowering therapies (April 15, 2006, through February 21, 2012). At week 30, patients initially receiving 10 µg of exenatide twice daily switched to 2 mg of exenatide once weekly. Study end points included changes from baseline in hemoglobin A1c, fasting plasma glucose, weight, lipids, and blood pressure. Long-term safety data included adverse events, liver and renal function, and heart rate. RESULTS: Of 258 extension-phase patients, 153 (59.3%) completed 5 years of treatment. Hemoglobin A1c levels were significantly and durably reduced from baseline (least-squares mean, -1.6%; 95% CI, -1.8% to -1.4%; vs -1.9% for exenatide once weekly at week 30), and 65 (43.9%) of 148 patients achieved hemoglobin A1c levels of less than 7.0%. Significant improvements in fasting plasma glucose level (-28.8 mg/dL; 95% CI, -36.2 to -21.5 mg/dL), weight (-3.0 kg; 95% CI, -4.6 to -1.3 kg), lipids, and diastolic blood pressure were observed, with minimal heart rate increase. Frequencies of nausea and injection-site reactions or nodules were decreased vs the initial 30-week controlled phase. Minor hypoglycemia occurred predominantly with sulfonylurea use, and no major hypoglycemia or new safety signals were observed. CONCLUSION: Long-term once weekly exenatide treatment was generally well tolerated with sustained glycemic improvement, weight reduction, and improved markers of cardiovascular risk in patients with type 2 diabetes. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00308139.

Incretin-based therapies.

Incretin-based therapies have established a foothold in the diabetes armamentarium through the introduction of oral dipeptidyl peptidase-4 inhibitors and the injectable class, the glucagon-like peptide-1 receptor agonists. In 2009, the American Diabetes Association and European Association for the Study of Diabetes authored a revised consensus algorithm for the initiation and adjustment of therapy in Type 2 diabetes (T2D). The revised algorithm accounts for the entry of incretin-based therapies into common clinical practice, especially where control of body weight and hypoglycemia are concerns. The gut-borne incretin hormones have powerful effects on glucose homeostasis, particularly in the postprandial period, when approximately two-thirds of the ß-cell response to a given meal is due to the incretin effect. There is also evidence that the incretin effect is attenuated in patients with T2D, whereby the ß-cell becomes less responsive to incretin signals. The foundation of incretin-based therapies is to target this previously unrecognized feature of diabetes pathophysiology, resulting in sustained improvements in glycemic control and improved body weight control. In addition, emerging evidence suggests that incretin-based therapies may have a positive impact on inflammation, cardiovascular and hepatic health, sleep, and the central nervous system. In the present article, we discuss the attributes of current and near-future incretin-based therapies.

Exenatide effects on diabetes, obesity, cardiovascular risk factors and hepatic biomarkers in patients with type 2 diabetes treated for at least 3 years.

BACKGROUND: Exenatide, an incretin mimetic for adjunctive treatment of type 2 diabetes (T2DM), reduced hemoglobin A(1c) (A1C) and weight in clinical trials. The objective of this study was to evaluate the effects of > or = 3 years exenatide therapy on glycemic control, body weight, cardiometabolic markers, and safety. METHODS: Patients from three placebo-controlled trials and their open-label extensions were enrolled into one open-ended, open-label clinical trial. Patients were randomized to twice daily (BID) placebo, 5 mug exenatide, or 10 mug exenatide for 30 weeks, followed by 5 mug exenatide BID for 4 weeks, then 10 mug exenatide BID for > or = 3 years of exenatide exposure. Patients continued metformin and/or sulfonylureas. RESULTS: 217 patients (64% male, age 58 +/- 10 years, weight 99 +/- 18 kg, BMI 34 +/- 5 kg/m(2), A1C 8.2 +/- 1.0% [mean +/- SD]) completed 3 years of exenatide exposure. Reductions in A1C from baseline to week 12 (-1.1 +/- 0.1% [mean +/- SEM]) were sustained to 3 years (-1.0 +/- 0.1%; p < 0.0001), with 46% achieving A1C < or = 7%. Exenatide progressively reduced body weight from baseline (-5.3 +/- 0.4 kg at 3 years; p < 0.0001). Patients with elevated serum alanine aminotransferase (ALT) at baseline (n = 116) had reduced ALT (-10.4 +/- 1.5 IU/L; p < 0.0001) and 41% achieved normal ALT. Patients with elevated ALT at baseline tended to lose more weight than patients with normal ALT at baseline (-6.1 +/- 0.6 kg vs. -4.4 +/- 0.5 kg; p = 0.03), however weight change was minimally correlated with baseline ALT (r = -0.01) or ALT change (r = 0.31). Homeostasis Model Assessment B (HOMA-B), blood pressure, and aspartate aminotransferase (AST) all improved. A subset achieved 3.5 years of exenatide exposure and had serum lipids available for analysis (n = 151). Triglycerides decreased 12% (p = 0.0003), total cholesterol decreased 5% (p = 0.0007), LDL-C decreased 6% (p < 0.0001), and HDL-C increased 24% (p < 0.0001). Exenatide was generally well tolerated. The most frequent adverse event was mild-to-moderate nausea. The main limitation of this study is the open-label, uncontrolled nature of the study design which does not provide a placebo group for comparison. CONCLUSION: Adjunctive exenatide treatment for > or = 3 years in T2DM patients resulted in sustained improvements in glycemic control, cardiovascular risk factors, and hepatic biomarkers, coupled with progressive weight reduction.

Metabolic effects of two years of exenatide treatment on diabetes, obesity, and hepatic biomarkers in patients with type 2 diabetes: an interim analysis of data from the open-label, uncontrolled extension of three double-blind, placebo-controlled trials.

BACKGROUND: Exenatide, an incretin mimetic for adjunctive treatment of type 2 diabetes mellitus (T2DM), reduced glycosylated hemoglobin (HbA(1c)) and weight in 30-week placebo-controlled trials. Some patients were followed up in open-label extensions to provide 'real-world' exenatide clinical experience. OBJECTIVE: The purpose of this study was to examine the metabolic effects of 2 years of exenatide treatment in patients with T2DM. METHODS: For this interim analysis, data were pooled from patients who completed 1 of three 30-week, multicenter, double-blind, placebo-controlled trials and their open-label extensions. In the initial trials, subjects were randomized to BID 5-microg exenatide, 10-microg exenatide, or placebo for 30 weeks. All subjects who enrolled in the extension phase then received 5-pg exenatide BID for 4 weeks, followed by open-label treatment with 10-pg exenatide BID. Subjects continued their existing metformin and/or sulfonylurea regimens. Analyses were conducted on data from all subjects who had the opportunity to achieve 2 years of exenatide exposure, irrespective of their treatment arm in the 30-week placebo-controlled trials. RESULTS: A total of 974 patients entered the open-label, extension phase of the trial. Two hundred eighty-three subjects (mean [SD] age, 57 [10] years; mean [SD] weight, 100[19] kg; sex, 63% male; mean [SD] body mass index, 34 [6] kg/m(2); mean [SD] HbA(1c), 8.3% [1.0%]) completed 2 years of exenatide treatment. Reductions in mean (SE) HbA(1c) from baseline to week 30 (-0.9% [0.1%]) were sustained through 2 years (-1.1% [0.1%]; P < 0.05 vs baseline), with 50% of the population achieving HbA(1c) < or = 7%. At week 30, exenatide was associated with a significant reduction in mean (SD) body weight from baseline (-2.1 [0.2] kg), with progressive reductions after 2 years (-4.7 [0.3] kg; P < 0.001 vs baseline). Patients with normal baseline alanine aminotransferase (ALT) (132/283 [47%]; normal: female < or =19 IU/L; male < or =30 IU/L) had no significant ALT change. However, patients with elevated ALT at baseline (151/283 [53%]) had a mean (SEM) reduction of ALT (-11 [1] IU/L from baseline 38 [1] IU/1; P < 0.05) and 39% achieved normal ALT by week 104. Patients with elevated ALT at baseline lost significantly more weight than patients with normal ALT at baseline (P = 0.04). However, weight change was minimally correlated with baseline ALT (r = -0.09) or ALT change (r = 0.31). Also, homeostasis model assessment of the beta-cell function (HOMA-B), blood pressure, and aspartate aminotransferase (AST) all improved. The most frequently reported adverse event was mild-to-moderate nausea. CONCLUSIONS: In these patients with T2DM, adjunctive exenatide treatment for 2 years was generally well tolerated and resulted in a sustained reduction of HbA(1c), progressive reduction in weight, and improvements in HOMA-B, blood pressure, and the hepatic injury biomarkers, AST and ALT.

Exenatide elicits sustained glycaemic control and progressive reduction of body weight in patients with type 2 diabetes inadequately controlled by sulphonylureas with or without metformin.

BACKGROUND: In two placebo-controlled 30-week trials, treatment with exenatide reduced HbA(1c) and body weight in patients with type 2 diabetes in the context of sulphonylurea (SU) or SU plus metformin (MET) as background treatment. This analysis examines the effects of 82 weeks of exenatide treatment for participants in these earlier 30-week trials. METHODS: Data were pooled from the two pivotal trials of exenatide added to SU or SU plus MET. Both 30-week, placebo-controlled trials of 5 microg or 10 microg exenatide b.i.d. were followed by 52-week open-label, uncontrolled extension studies in which all participants received 10 microg exenatide b.i.d. and continued prior oral therapies. This interim analysis includes data for 222 patients who completed 82 weeks of exenatide treatment (61% M, age 57 +/- 10 y, weight 99 +/- 21 kg, BMI 34 +/- 6 kg/m(2), HbA(1c)8.4 +/- 1.0% [mean +/- SD]). RESULTS: Reduction in HbA(1c) from baseline to week 30 (-0.8 +/- 0.1% and -1.0 +/- 0.1% for 5 microg b.i.d. and 10 microg b.i.d., respectively [mean +/- SE]) was sustained up to week 82 (-1.0 +/- 0.1%). Of 207 patients with baseline HbA(1c) > 7%, 44% achieved HbA(1c) < or = 7% at week 82. Reduction of body weight from baseline to week 30 (-1.4 +/- 0.3 kg and -2.1 +/- 0.3 kg for 5 microg b.i.d. and 10 microg b.i.d., respectively) was progressive up to week 82 (-4.0 +/- 0.3 kg). The most frequent adverse events were nausea and hypoglycaemia, both generally mild to moderate in intensity. CONCLUSIONS: Exenatide added to maximally effective doses of SU or SU plus MET resulted in a sustained reduction in HbA(1c) and a progressive reduction in weight over 1 1/2 years.

Effects of pramlintide on postprandial glucose excursions and measures of oxidative stress in patients with type 1 diabetes.

OBJECTIVE: Oxidative stress has been shown to be increased in the postprandial period in patients with diabetes and has been implicated in the pathogenesis of micro- and macrovascular complications. The aim of this post hoc analysis was to assess the effects of pramlintide, an amylin analog shown to reduce postprandial glucose excursions in patients with diabetes, on markers of oxidative stress in the postprandial period. RESEARCH DESIGN AND METHODS: In a randomized, single-blind, placebo-controlled, crossover study, 18 evaluable subjects with type 1 diabetes underwent two standardized breakfast meal tests and received pramlintide or placebo in addition to their preprandial insulin. The plasma concentrations of glucose and markers of oxidative stress (nitrotyrosine, oxidized LDL [ox-LDL], and total radical-trapping antioxidant parameter [TRAP]) were measured at baseline and during the 4-h postprandial period. RESULTS: Compared with placebo, pramlintide treatment significantly reduced postprandial excursions of glucose, nitrotyrosine, and ox-LDL and prevented a decline in TRAP (P < 0.03 for all comparisons). Correlation analyses adjusted for treatment revealed a significant association between postprandial mean incremental area under the curve from 0 to 4 h (AUC(0-4 h)) for glucose and postprandial mean incremental AUC(0-4 h) for each measure of oxidative stress (r = 0.75, 0.54, and -0.63 for nitrotyrosine, ox-LDL, and TRAP, respectively; P < 0.001 for all correlations). CONCLUSIONS: These findings indicate that the postprandial glucose-lowering effect of pramlintide in type 1 diabetes is associated with a significant reduction in postprandial oxidative stress.

Effect of pramlintide on weight in overweight and obese insulin-treated type 2 diabetes patients.

OBJECTIVE: Several randomized, placebo-controlled, double-blind trials in insulin-treated patients with type 2 diabetes have shown that adjunctive therapy with pramlintide reduces hemoglobin (Hb)A1c with concomitant weight loss. This analysis further characterizes the weight-lowering effect of pramlintide in this patient population. RESEARCH METHODS AND PROCEDURES: This pooled post hoc analysis of two long-term trials included all patients who were overweight/obese at baseline (BMI > 25 kg/m2), and who were treated with either 120 microg pramlintide BID (n = 254; HbA1c 9.2%; weight, 96.1 kg) or placebo (n = 244; HbA1c 9.4%; weight, 95.0 kg). Statistical endpoints included changes from baseline to week 26 in HbA1c, body weight, and insulin use. RESULTS: Pramlintide treatment resulted in significant reductions from baseline to week 26, compared with placebo, in HbA1c and body weight (both, p < 0.0001), for placebo-corrected reductions of -0.41% and -1.8 kg, respectively. Approximately three times the number of patients using pramlintide experienced a > or = 5% reduction of body weight than with placebo (9% vs. 3%, p = 0.0005). Patients using pramlintide also experienced a proportionate decrease in total daily insulin use (r = 0.39, p < 0.0001). The greatest placebo-corrected reductions in weight at week 26 were observed in pramlintide-treated patients with a BMI >40 kg/m2 and in those concomitantly treated with metformin (both, p < 0.001), for placebo-corrected reductions of -3.2 kg and -2.5 kg, respectively. DISCUSSION: These findings support further evaluation of the weight-lowering potential of pramlintide in obese patients with type 2 diabetes.

Pramlintide reduces postprandial glucose excursions when added to insulin lispro in subjects with type 2 diabetes: a dose-timing study.

BACKGROUND: To assess the postprandial glucose-lowering effect of the human amylin analog pramlintide when given with insulin lispro in subjects with type 2 diabetes, with an emphasis on the optimal dose timing relative to meals. METHODS: In this randomized, single-blind, placebo-controlled, five-way crossover study, 19 subjects with type 2 diabetes using insulin lispro underwent five consecutive mixed-meal tests. In randomized order, subjects received subcutaneous injections of placebo at -15 min or 120-microg pramlintide at -15, 0, +15, or +30 min relative to the standardized breakfast after an overnight fast. Insulin lispro was injected at 0 min at doses that were adjusted appropriately for both the content of the standardized meal and the anticipated effects of pramlintide. Plasma glucose concentrations were measured before and during the 4-h postmeal period. RESULTS: When injected at 0 min, pramlintide reduced the postprandial glucose excursion by 81% compared to insulin lispro + placebo (incremental AUC(0-4 h) (mean +/- SE) 2.0 +/- 1.5 vs. 10.4 +/- 2.2 mmol/h/L, P<0.05). When pramlintide was injected at -15, +15, and +30 min, the postprandial incremental glucose AUC(0-4 h) was also significantly reduced (P<0.05), but to a lesser extent (42 to 73%). Pramlintide treatment was well tolerated and no serious adverse events were reported. CONCLUSIONS: Administration of pramlintide either at or just prior to a meal caused a greater reduction in postprandial glucose than either administration of placebo or postmeal pramlintide injections in subjects with type 2 diabetes treated with a rapid-acting insulin analog, insulin lispro.

Pramlintide reduces postprandial glucose excursions when added to regular insulin or insulin lispro in subjects with type 1 diabetes: a dose-timing study.

OBJECTIVE: To assess the postprandial glucose-lowering effect of the human amylin analog pramlintide when given with either regular insulin or insulin lispro in subjects with type 1 diabetes, with an emphasis on the optimal dose timing relative to meals. RESEARCH DESIGN AND METHODS: In this randomized, single-blind, placebo-controlled, five-way crossover study, 19 subjects with type 1 diabetes using regular insulin and 21 subjects with type 1 diabetes using insulin lispro underwent five consecutive mixed meal tests. In randomized order, subjects received subcutaneous injections of placebo at -15 min or 60 microg pramlintide at -15, 0, +15, or +30 min relative to the meal after an overnight fast. Regular insulin or insulin lispro was injected at -30 and 0 min, respectively, at doses that were adjusted appropriately for both the content of the standardized meal and the anticipated effects of pramlintide. Plasma glucose concentrations were measured before and during the 4-h postmeal period. RESULTS: In both the regular insulin and insulin lispro groups, pramlintide injections at all four time points lowered the postprandial glucose excursion (36 to >100% reduction in incremental area under the concentration time curve from 0 to 4 h (AUC(0-4 h)) compared with placebo. However, only preprandial injections of pramlintide (-15 and 0 min) were able to prevent the initial postprandial surge in glucose. The optimal time for pramlintide injection was 0 min, which reduced the postprandial glucose excursion by >100% compared with regular insulin plus placebo (incremental AUC(0-4 h): -0.6 +/- 2.5 vs. 11.0 +/- 2.9 mmolx h(-1) x l(-1), P < 0.0007) and by 75% compared with insulin lispro plus placebo (incremental AUC(0-4 h): 2.5 +/- 2.1 vs. 10.0 +/- 2.5 mmol x h(-1) x l(-1), P < 0.0098). No serious adverse events were reported. CONCLUSIONS: Pramlintide, given at or just before a meal, reduces the postprandial glucose excursion in subjects with type 1 diabetes, regardless of whether added to regular insulin or a rapid-acting insulin analog.

Pramlintide as an adjunct to insulin therapy improves long-term glycemic and weight control in patients with type 2 diabetes: a 1-year randomized controlled trial.

OBJECTIVE: Mealtime amylin replacement with the human amylin analog pramlintide, as an adjunct to mealtime insulin replacement, reduces postprandial glucose excursions in patients with type 2 diabetes. The aim of the present study was to assess the long-term efficacy and safety of pramlintide in this patient population. RESEARCH DESIGN AND METHODS: In a 52-week, double-blind, placebo-controlled, parallel-group, multicenter study, 656 patients with type 2 diabetes (age 57 +/- 10 years, diabetes duration 12 +/- 7 years, BMI 34.0 +/- 7.0 kg/m(2), HbA(1c) 9.1 +/- 1.2%, mean +/- SD) treated with insulin (alone or in combination with sulfonylureas and/or metformin) were randomized to receive additional preprandial subcutaneous injections of either placebo or pramlintide (60 micro g TID, 90 microg BID, or 120 microg BID). RESULTS: Treatment with pramlintide 120 micro g BID led to a sustained reduction from baseline in HbA(1c) (-0.68 and -0.62% at weeks 26 and 52, respectively), which was significantly greater than that seen with placebo (P < 0.05). The proportion of patients achieving an HbA(1c) <8% was approximately twofold greater with pramlintide (120 microg BID) than with placebo (46 vs. 28%, P < 0.05). The glycemic improvement with pramlintide 120 micro g BID was accompanied by a mean weight loss (-1.4 kg vs. +0.7 kg with placebo at week 52, P < 0.05) and occurred without an overall increase in the severe hypoglycemia event rate. The most common adverse event associated with pramlintide use was transient, mild-to-moderate nausea. CONCLUSIONS: Mealtime amylin replacement with pramlintide 120 microg BID, as an adjunct to insulin therapy, improves long-term glycemic and weight control in patients with type 2 diabetes.

Impact of pramlintide on glucose fluctuations and postprandial glucose, glucagon, and triglyceride excursions among patients with type 1 diabetes intensively treated with insulin pumps.

OBJECTIVE: To assess the effects of adjunctive treatment with pramlintide, an analog of the beta-cell hormone amylin, on 24-h glucose fluctuations and postprandial glucose, glucagon, and triglyceride excursions in patients with type 1 diabetes intensively treated with continuous subcutaneous insulin infusion (CSII). RESEARCH DESIGN AND METHODS: In this study, 18 patients (16 of whom could be evaluated) with type 1 diabetes (age 44 +/- 11 years, HbA(1c) 8.2 +/- 1.3% [mean +/- SD]) were given mealtime injections of 30 micro g pramlintide t.i.d. for 4 weeks in addition to their preexisting CSII regimen (16 lispro, 2 regular insulin). Mealtime insulin boluses were reduced by a minimum of 10% during the first 3 days, and re-adjusted thereafter based on clinical judgment. At weeks 0 (baseline), 4 (on treatment), and 6 (2 weeks off treatment), 24-h interstitial glucose concentrations were measured using a continuous glucose monitoring system (CGMS), and postprandial plasma glucose, glucagon, and triglyceride concentrations were measured in response to a standardized test meal. RESULTS: At baseline, patients had excessive 24-h glucose fluctuations, with 59% of the CGMS measurements >140 mg/dl, 13% <80 mg/dl, and only 28% in the euglycemic range (80-140 mg/dl). After 4 weeks on pramlintide, measurements in the hyperglycemic range declined to 48% and measurements within the euglycemic range increased to 37%. This shift from the hyperglycemic to the euglycemic range occurred with a concomitant 17% reduction in mealtime insulin dosages and without relevant increases in measurements below the euglycemic range (15%) or any severe hypoglycemic events. After 4 weeks on pramlintide, postprandial glucose, glucagon, and triglyceride excursions were reduced by approximately 86, approximately 87, and approximately 72%, respectively (incremental areas under the curve, all P < 0.05 vs. baseline). At week 6 (off treatment), the 24-h glucose profile and postprandial glucose, glucagon, and triglyceride excursions approached pretreatment values. CONCLUSIONS: In this study, the addition of pramlintide to insulin therapy reduced excessive 24-h glucose fluctuations as well as postprandial glucose, glucagon, and triglyceride excursions in patients with type 1 diabetes intensively treated with insulin pumps.

Striking differences in glucose and lactate levels between brain extracellular fluid and plasma in conscious human subjects: effects of hyperglycemia and hypoglycemia.

Brain levels of glucose and lactate in the extracellular fluid (ECF), which reflects the environment to which neurons are exposed, have never been studied in humans under conditions of varying glycemia. The authors used intracerebral microdialysis in conscious human subjects undergoing electrophysiologic evaluation for medically intractable epilepsy and measured ECF levels of glucose and lactate under basal conditions and during a hyperglycemia-hypoglycemia clamp study. Only measurements from nonepileptogenic areas were included. Under basal conditions, the authors found the metabolic milieu in the brain to be strikingly different from that in the circulation. In contrast to plasma, lactate levels in brain ECF were threefold higher than glucose. Results from complementary studies in rats were consistent with the human data. During the hyperglycemia-hypoglycemia clamp study the relationship between plasma and brain ECF levels of glucose remained similar, but changes in brain ECF glucose lagged approximately 30 minutes behind changes in plasma. The data demonstrate that the brain is exposed to substantially lower levels of glucose and higher levels of lactate than those in plasma; moreover, the brain appears to be a site of significant anaerobic glycolysis, raising the possibility that glucose-derived lactate is an important fuel for the brain.

A randomized study and open-label extension evaluating the long-term efficacy of pramlintide as an adjunct to insulin therapy in type 1 diabetes.

OBJECTIVE: To assess the effect of mealtime amylin replacement with pramlintide on long-term glycemic and weight control in patients with type 1 diabetes. RESEARCH DESIGN AND METHODS: In a 52-week, double-blind, placebo-controlled, multicenter study, 480 patients with type 1 diabetes were randomized to receive preprandial injections of placebo or 30 microg pramlintide q.i.d., in addition to existing insulin regimens. At week 20, pramlintide-treated patients were re-randomized to 30 or 60 microg pramlintide q.i.d. if decreases from baseline in HbA(1c) were <1% at week 13. Of the 342 patients who completed the 52-week study, 236 individuals ( approximately 70%) elected to participate in a 1-year open-label extension in which all patients received 30 or 60 microg pramlintide q.i.d. RESULTS: Treatment with pramlintide led to a mean reduction in HbA(1c) of 0.67% from baseline to week 13 that was significantly (P < 0.0001) greater than the placebo reduction (0.16%), and a significant placebo-corrected treatment difference was sustained through week 52 (P = 0.0071). The greater HbA(1c) reduction was associated with an average weight loss, rather than weight gain, and was not accompanied by an increased overall event rate of severe hypoglycemia. In the open-label extension, mean HbA(1c) levels decreased rapidly in patients receiving pramlintide for the first time and remained at reduced levels in patients who continued pramlintide treatment. The most common adverse events reported by the pramlintide group were mild nausea and anorexia, which both occurred during the initial weeks of treatment and dissipated over time. CONCLUSIONS: Mealtime pramlintide treatment as an adjunct to insulin improved long-term glycemic control without inducing weight gain or increasing the overall risk of severe hypoglycemia in patients with type 1 diabetes.