Effects of exenatide twice daily versus sitagliptin on 24-h glucose, glucoregulatory and hormonal measures: a randomized, double-blind, crossover study

AIM

To compare exenatide and sitagliptin glucose and glucoregulatory measures in subjects with type 2 diabetes.

METHODS

An 8-week, double-blind, randomized, crossover, single-centre study. Eighty-six subjects (58% female, body mass index 35 ± 5 kg/m², haemoglobin A1c 8.3 ± 1.0%) received either exenatide 10 µg (subcutaneous) twice daily or sitagliptin 100 mg (oral) daily for 4 weeks and crossed to the other therapy for an additional 4 weeks. Main outcome was time-averaged glucose during the 24-h inpatient visits.

RESULTS

Both treatments decreased average 24-h glucose, but exenatide had a greater effect [between-group difference: -0.67 mmol/l, 95% confidence interval (CI): -0.9 to -0.4 mmol/l]. Both treatments decreased 2-h postprandial glucose (PPG), area under the curve of glucose above 7.8 mmol/l (140 mg/dl) and 11 mmol/l (200 mg/dl) and increased the time spent with glucose between 3.9 and 7.8 mmol/l (70 and 140 mg/dl) during 24 h, but exenatide had a significantly greater effect (p < 0.05). Both treatments decreased postprandial serum glucagon, with exenatide having a greater effect (p < 0.005). Both treatments decreased fasting blood glucose to a similar degree (p = 0.766). Sitagliptin increased, while exenatide decreased, postprandial intact glucagon-like peptide-1. Both drugs improved homeostasis model assessment of β-cell function (HOMA-B), with exenatide having a significantly greater effect (p = 0.005). Both exenatide and sitagliptin decreased 24-h caloric intake, with exenatide having a greater effect (p < 0.001). There was no episode of major hypoglycaemia. Adverse events were mild to moderate and mostly gastrointestinal in nature with exenatide. No study withdrawals were due to an adverse event.

CONCLUSION

Compared to sitagliptin, exenatide showed significantly lower average 24-h glucose, 2-h PPG, glucagon, caloric intake and improved HOMA-B.

Healthcare charges and utilization associated with diabetic neuropathy: impact of Type 1 diabetes and presence of other diabetes-related complications and comorbidities

AIMS

The aim was to examine the impact of Type 1 diabetes and having any other diabetes-related complication or comorbidity on healthcare charges and utilization in patients with diabetic neuropathy (DN).

METHODS

We selected individuals aged < 65 years who continuously enrolled in a large US commercial plan from July 2004 to June 2006 and who received at least one diagnosis of DN at any time from July 2004 to June 2005. We compared the prevalence of other diabetes-related complications or comorbidities between patients with Type 1 and with Type 2 diabetes. In patients with DN with or without any other diabetes-related complication or comorbidity, we used multivariate regression to assess the marginal contribution of Type 1 diabetes on healthcare charges and utilization from July 2005 until June 2006.

RESULTS

The majority of DN patients had at least one other diabetes-related complication or comorbidity. Most of the DN patients had Type 2 diabetes. DN patients with Type 1 diabetes had more comorbid medical conditions than those with Type 2 diabetes. Compared with Type 2, Type 1 patients had a higher prevalence of each individual non-DN diabetes-related complication or comorbidity, except heart disease. Controlling for comorbidities, Type 1 and Type 2 patients with DN but no other diabetes-related complication or comorbidity had similar healthcare utilization. However, Type 1 patients had significantly higher charges than those with any other diabetes-related complication or comorbidity.

CONCLUSIONS

Many patients with DN have Type 1 diabetes and other common diabetes-related complications or comorbidities, which can have a significant impact on healthcare charges and utilization.

A current review of olanzapine's safety in the geriatric patient: from pre-clinical pharmacology to clinical data

OBJECTIVE

Olanzapine (OLZ) is unique among currently available antipsychotic medications in its antagonism of a range of receptor systems including dopamine, norepinephrine, serotonin, acetylcholine, and histamine. Olanzapine's mechanistic complexity provides a broad efficacy profile in patients with schizophrenia and acute, pure or mixed mania. Patients experience symptomatic relief of mania, anxiety, hallucinations, delusions, and agitation/aggression and reduced depressive, negative, and some cognitive symptoms. This paper will review the safety profile of OLZ, focusing on the elderly, where data are available.

METHOD

Preclinical and clinical studies of OLZ are reviewed, with emphasis on its possible effects on the cholinergic system and the histamine H(1) receptor. Weight change and related metabolic considerations, cardiac and cardiovascular safety, and motor function during treatment with OLZ are also reviewed.

RESULTS AND CONCLUSION

In vitro receptor characterization methods, when done using physiologically relevant conditions allow accurate prediction of the relatively low rate of anticholinergic-like adverse events, extrapyramidal symptoms, and cardiovascular adverse events during treatment with OLZ. Currently available clinical data suggest olanzapine is predictably safe in treating adult patients of any age with schizophrenia and acute bipolar mania, as well as in treatment of patients with some types of neurodegenerative disorders.

A comparison of insulin lispro and buffered regular human insulin administered via continuous subcutaneous insulin infusion pump

This study compared glycemic control achieved with insulin lispro or buffered regular human insulin in patients with Type 1 diabetes treated with continuous subcutaneous insulin infusion (CSII) using an external insulin pump. In this 24-week multicenter, randomized, two-way crossover, open-label trial, 58 patients on CSII with adequate glycemic control received either insulin lispro or buffered regular human insulin for 12 weeks, followed by the alternate treatment for another 12 weeks. Efficacy and safety measures included hemoglobin A(1c) (HbA(1c)) at baseline and endpoint, home blood glucose monitoring, hypoglycemia, and frequency of pump catheter occlusion. Patients consumed a standard test meal on three occasions, with determinations of fasting, 1- and 2-h postprandial glucose values. Insulin lispro use was associated with a significantly lower HbA(1c) than was buffered regular human insulin (7.41+/-0.97 vs. 7.65+/-0.85 mmol/l; P=.004). Fasting serum glucose values before the test meal were similar between the two therapies. The 1-h (11.16+/-4.29 vs. 13.20+/-4.68 mmol/l; P=.012) and 2-h (9.64+/-4.10 vs. 12.53+/-4.64 mmol/l; P=.001) postprandial glucose concentrations were significantly lower during treatment with insulin lispro. No differences between treatments were observed in basal or bolus insulin doses, weight gain, or the incidence and rate of hypoglycemia, hyperglycemia, or pump occlusions. When used in external pumps, insulin lispro provides better glycemic control than buffered regular human insulin with a similar adverse event profile.

Insulin lispro lowers postprandial glucose in prepubertal children with diabetes

OBJECTIVE

This study compared the glucose-lowering effect of insulin lispro, given before or after meals, with regular human insulin given before meals in prepubertal children with diabetes.

RESEARCH DESIGN AND METHODS

A 3-way crossover, open-label study involving 61 prepubertal children (ages 2.9-11.4 years) with type 1 diabetes. The children were randomly assigned to receive regular human insulin 30 to 45 minutes before meals, insulin lispro within 15 minutes before or immediately after meals, combined with basal insulin. Each treatment lasted 3 months. Hemoglobin A(1c) levels and home glucose monitoring profiles were measured at the end of each treatment period.

RESULTS

Treatment with insulin lispro before breakfast resulted in lower 2-hour postprandial glucose values than regular human insulin (11.7 +/- 4.4 mmol/L vs 15.0 +/- 5.4 mmol/L). Similarly, insulin lispro given before dinner resulted in lower blood glucose values 2 hours postprandially (8.8 +/- 5.0 mmol/L vs 10.8 +/- 5.4 mmol/L) than regular human insulin. When insulin lispro was administered after meals, the 2-hour glucose levels were between those seen with either insulin lispro or regular human insulin given before meals. The number and types of adverse events, the rates of hypoglycemia, and the HbA(1c) levels did not differ among the 3 therapies.

CONCLUSIONS

In prepubertal children, insulin lispro given before meals is safe and significantly lowers postprandial glucose levels after breakfast and dinner compared with regular human insulin, and insulin lispro given after the meal provides similar benefits as regular human insulin before the meal.

Patient and physician satisfaction with the Humulin/Humalog Pen, a new 3.0-mL prefilled pen device for insulin delivery

OBJECTIVE

This study assessed acceptability of a new 3.0-mL prefilled insulin pen device, the Humulin/Humalog Pen, as a method of delivering human insulin. Secondary objectives were to determine whether the pen device might facilitate initiation of insulin therapy in patients currently receiving oral antihyperglycemic agents and to monitor the safety of this pen device in clinical practice.

BACKGROUND

For both the patient and health care provider, significant negative perceptions of the use of insulin therapy persist, including patient inconvenience, social stigma from insulin injections, and insufficient time for the provider to train the patient.

METHODS

This 6-week, open-label, noncomparative study was conducted at 33 centers in the United States. Patients with type 1 or type 2 diabetes treated with insulin therapy or oral antihyperglycemic agents were enrolled in the study. Before the study, 62% (194 patients) had used a syringe and vial for insulin injection, 28% (87 patients) had used an insulin pen device, and 10% (30 patients) were insulin-naive. Prior therapy was unknown in 1% (4 patients). Patients used the Humulin/Humalog Pen for > or = 1 injection of insulin daily for 6 weeks. At the beginning and end of the study, patients completed a questionnaire designed to elicit their perceptions of the Humulin/Humalog Pen; physicians completed a questionnaire at the end of the study. Frequencies and percentages of all categoric responses were calculated and summarized.

RESULTS

A total of 315 patients (136 type 1, 179 type 2 diabetes) were enrolled. Of the 299 patients who completed questionnaires at the end of the study, 76% (226 patients) were somewhat or extremely satisfied with the pen, 78% (234 patients) probably or definitely would continue to use the pen, and 80% (239 patients) probably or definitely would recommend the pen to others. Of the 33 physicians who completed questionnaires at the end of the study, 97% (32) thought that the pen was better overall compared with a vial and syringe, 88% (29) thought that it took less time to teach patients to use the pen, and 73% (24) thought that it took less time to initiate insulin therapy with the pen.

CONCLUSIONS

The Humulin/Humalog Pen had an acceptable safety profile and was well accepted by patients and physicians.

Pharmacokinetic and glucodynamic comparisons of recombinant and animal-source glucagon after IV, IM, and SC injection in healthy volunteers

The structure of the hormone glucagon is identical among humans and several species of other mammals. Equivalence of recombinant glucagon (rG) to animal-source glucagon (aG) was assessed in this two-part, open-label, randomized study. Part I was a four-way crossover intravenous dose-ranging study of rG (pH 2.8) involving 12 subjects. Part II was a six-way crossover study of 29 subjects comparing rG (diluent pH 2.0 and 2.8) with aG administered subcutaneously (sc) and intramuscularly (im). Maximum glucagon plasma concentrations (C(max)) and area under the glucagon concentration curve (AUC) were calculated. Additionally, maximum blood glucose concentrations (BG(max)), maximum absolute BG excursion (MAE), and area under the glucose concentration curve from time of dosing to return to baseline (AUC(rtb)) were calculated. The primary focus was equivalence of the formulation intended for marketing (rG pH 2.0) to aG. Administration of rG pH 2.0 through the im route demonstrated equivalence to aG for all pharmacokinetic and glucodynamic comparisons. Subcutaneous administration of rG pH 2.0 demonstrated standard bioequivalence for AUC (5.87 versus 6.63 ng x h/mL; NS) and near equivalence for C(max) (7.94 versus 9.12 ng/mL; p < 0.05). rG pH 2.0 showed glucodynamic equivalence to aG (BG(max), 136 versus 133 mg/dL; MAE, 50.0 versus 47.4 mg/dL, respectively) and statistically greater AUC(rtb) values (151 versus 126 mg x h/dL, p < 0. 05). rG and aG were equally safe and well tolerated. In conclusion, rG provides equivalent safety and efficacy to aG.

Prolonged efficacy of short acting insulin Lispro in combination with human ultralente in insulin-dependent diabetes mellitus

Insulin Lispro is a newly FDA approved analog of human insulin that exhibits rapid absorption and a short duration of action after sc injection. Although Lispro insulin improves immediate postprandial glycemia compared to Regular insulin, long term trials of Lispro insulin have not shown improvement in overall glycemic control, as determined by glycosylated hemoglobin. We hypothesize that this lack of improvement is attributable to the development of late postprandial hyperglycemia secondary to a waning of Lispro insulin's effect in conjunction with continued meal absorption. This study was designed to evaluate the duration of Lispro-induced reductions in plasma glucose after a standardized meal when Lispro insulin is incorporated into a regimen typically employed in insulin-dependent diabetes mellitus. After establishment of euglycemia overnight, 12 healthy IDDM patients received human Ultralente insulin (0.2 U/kg) alone and in combination with each of the following treatments in random sequence immediately before ingesting a 750-Cal American Diabetes Association breakfast: 1) 0.15 U/kg human Regular insulin (Regular 0.15 group), 2) 0.15 U/kg Lispro insulin (Lispro 0.15 group), 3) 0.1 U/kg Lispro insulin (Lispro 0.1 group), and 4) an equimolar (1:1) mixture of Lispro and Regular insulins (0.15 U/kg; 1:1 Mix group). Glucose and hormonal parameters were assessed for 8 h after the meal. Peak postprandial glucose was increased in the Regular insulin group compared to that in all groups that incorporated Lispro insulin (P < 0.001). Glucose area under the curve (AUC) was decreased in the Lispro 0.15 group compared to that in the Lispro 0.1 group, and glucose AUC was decreased in the Lispro 0.15 and 1:1 Mix groups compared to that in the group given Regular insulin (P < 0.001). Mean plasma glucose concentrations during the final hour of study were increased in the Ultralente group compared with those in all other treatment groups and were increased in the Lispro 0.1 group compared with those in the Regular, Lispro 0.15, and 1:1 Mix groups (P < 0.05). Insulin AUC was significantly reduced in the Lispro 0.1 group compared to those in all other short acting insulin groups (P < 0.001), and time to peak insulin was more rapid in the two Lispro groups than those in all other treatment groups (P < 0.01). The glucagon response was significantly greater in the Ultralente group compared to those with all other treatments. There was no difference in the development of hypoglycemia between the groups. This study demonstrates that the reductions in plasma glucose effected by Lispro insulin are consistent and stable for 8 h after meal ingestion when Lispro insulin is used in combination with human Ultralente insulin. These findings suggest that improvement in overall glycemia, as assessed by glycosylated hemoglobin, may be achievable with Lispro insulin if adequate doses are administered.

Approaching final height in children treated for growth hormone deficiency

This brief report is a preliminary review of the interpretation of 'final height' in a large study of children, some of whom have been treated with recombinant human growth hormone for as long as 8 years. Most of the children in this study have not attained final height, so we highlight the issues relating to the definition of final height, study completion and diagnosis.

The role of body mass in the response to growth hormone therapy

Obesity is associated with normal or increased growth despite diminished GH secretion compared to lean children. The mechanism by which adequate growth is maintained in the presence of low GH levels is unknown, but is possibly mediated at the GH receptor level. To probe this hypothesis, we examined the relationship between GH responsivity, body mass index (BMI) and plasma GH-binding protein (GH-BP)/receptor level in 43 GH-deficient children during treatment with a fixed dose of GH (0.18 mg/kg.week). Before treatment, BMI [expressed as standard deviation score (SDS) for age (BMI-SDS)] did not correlate with either growth velocity or serum insulin-like growth factor-I (IGF-I). In contrast, after 12 months of GH therapy BMI-SDS correlated directly with plasma IGF-I (P < 10(-5)) and growth velocity (P < 10(-3)). These findings parallel those obtained for GH-BP vs. the response to GH, suggesting that BMI and GH-BP are covariants. The interrelationships among BMI, GH-BP, and response to GH were further probed by multiple regression analysis. Partial correlation coefficients vs. response to GH were consistently stronger for GH-BP than for BMI-SDS, indicating that GH-BP is the dominant factor between these two covariants in determining responsiveness to GH. The data suggest a primary role for GH-BP/receptor levels in determining GH action, with secondary but significant effects of nutrition and degree of adiposity. The latter may be mediated through the impact of nutrition and body mass on GH-BP/receptor levels.

Serum growth hormone (GH)-binding protein/receptor: an important determinant of GH responsiveness

Individual growth rates (or responses to GH therapy) and adult heights vary over a wide range. The reasons for this variation are poorly understood. Based on the reciprocal relationship between GH production and serum GH-binding protein/receptor (GH-BP), we hypothesized that genetic growth potential was achieved by a specific combination of GH-BP/receptor and GH production in each individual. To address the question whether GH production regulates GH-BP, or vice versa, we studied GH-deficient children, where one of the parameters, GH exposure, could be controlled through exogenous administration. Forty-three untreated prepubertal GH-deficient children were studied before and after 6 and 12 months of GH replacement therapy (0.18 mg/kg.week). Growth velocity, height, bone age, weight and their respective Z scores, serum GH-BP, and serum insulin-like growth factor I (IGF-I) were measured at each time point. The patients responded with significant increases in serum IGF-I, age-adjusted growth velocity, and height (P < 10(-6) for all). Before therapy, GH-BP correlated directly with chronologic and bone age (P < 10(-4), but not with either growth velocity or IGF-I. In contrast, GH-BP correlated strongly with the response to therapy whether assessed as the incremental change in IGF-I (P < 10(-6)) or as the increase in growth velocity (P approximately 0.003). GH treatment had no consistent effect on GH-BP/receptor levels. These findings support the concept that the GH-BP/receptor endowment is characteristic for an individual and plays a pivotal role in somatic growth. The GH-BP/receptor system and its ontogeny appears relatively independent of regulation by GH. Differences in individual GH-BP/GH receptor complement account for some of the variability in the response to GH, and GH-BP levels may serve as a predictor for the degree of response. The reciprocal relationship between GH production and GH-BP in normal subjects probably results from adjustment of GH secretion to accommodate the prevailing GH-BP/receptor environment.

Biosynthetic human growth hormone in the treatment of growth hormone deficiency

A total of 309 previously untreated children with growth hormone deficiency (GHD) (219 boys, 90 girls; mean age 8.4 +/- 3.9 years, range 1.5-19 years) were treated for up to 3 years in an ongoing trial designed to examine the long-term efficacy and safety of biosynthetic somatropin (rhGH). The children were treated with rhGH, 0.06 mg/kg (0.16 IU/kg) three times weekly. In the prepubertal children, the mean height velocity increased during the first year from 3.8 +/- 1.8 cm/year to 8.9 +/- 2.2 cm/year (n = 188). During the second and third years, their height velocities were 7.1 +/- 1.1 (n = 147) and 6.3 +/- 1.2 cm/year (n = 64), respectively. The height velocity SDS increased from -2.5 +/- 1.9 before treatment to 3.1 +/- 2.6 during the first year of treatment in the prepubertal children. The mean pretreatment height velocity in those with idiopathic GHD (3.8 +/- 1.6 cm/year) did not differ from that in children with organic GHD (3.8 +/- 2.3 cm/year). In addition, the height velocities during the first year of therapy did not differ significantly with respect to the aetiology of GHD. For the children who entered puberty during the study, the mean height velocity increased from 3.0 +/- 1.7 cm/year before treatment to 8.4 +/- 2.3 cm/year during the first year of rhGH therapy. In the first year, the height velocity of children with a bone age of less than 5 years (9.4 +/- 2.3 cm/year) was significantly greater than that in children with a bone age of 5-10 years (8.4 +/- 1.8 cm/year) or greater than 10 years (7.8 +/- 2.2 cm/year: p = 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of adrenal cortical tumors in children and adults

Morphologic features (abnormal mitoses, necrosis, vascular and capsular invasion, broad fibrous bands, cellular pleomorphism, size) previously suggested to be predictors of malignant behavior in adrenal cortical tumors were assessed individually in 23 (17 benign, 6 malignant) pediatric and 42 (29 benign, 13 malignant) adult tumors. Of these features, size was the only predictor of malignancy in pediatric tumors. All pediatric tumors weighing more than 500 g were malignant and all but one weighing less than 500 g were benign. The remaining features were present in both benign and malignant pediatric tumors, and pediatric benign tumors were significantly more likely to have mitoses (P less than 0.01), necrosis (P less than 0.001), broad fibrous bands (P less than 0.005), and moderate to severe pleomorphism (P less than 0.01) than were adult benign tumors. The authors conclude that pediatric tumors are more likely to be benign than previously thought, and that size is the only morphologic predictor of their biologic behavior.

Plasma lipids and apolipoproteins in a 13-year-old boy with diabetic ketoacidosis and extreme hyperlipidemia

A 13-year-old boy with untreated diabetes presented in severe ketoacidosis (DKA) for the first time with an initial triglyceride (TG) level of 14,461 mg/dl. Serial blood samples were drawn to determine the interrelationships of changes in lipids and apolipoproteins during treatment with insulin and intravenous fluids. The TG level declined to 122 mg/dl in 7 days concomitant with a lowering of apolipoproteins C-II, C-III, E, D, and F. Further observations suggested that the TG-rich lipoproteins underwent degradation associated with a decline in the levels of apolipoproteins associated with very low density lipoprotein (VLDL) in contrast to an increase in high density lipoprotein-cholesterol (HDL-C), ApoA-I and ApoA-II. ApoB and low density lipoprotein cholesterol (LDL-C) were increased transiently. Subsequent therapy with continuous subcutaneous insulin infusion (CSII) were effective in maintaining glucose homeostasis and normolipidemia for 6 months.

Studies of lipids, lipoproteins, and apolipoproteins in Menkes' disease

Three patients with Menkes' disease, an inherited disorder of copper transport, were studied to determine whether the copper deficiency was associated with a lipoprotein disorder. Hypocuprinemia was documented in all three cases. Two patients had severe copper and ceruloplasmin deficiencies, whereas the third patient had a less severe deficiency. Hypertriglyceridemia was observed in the first patient, and elevations in triglyceride, cholesterol, apolipoprotein B (ApoB), and apolipoprotein C-III (ApoC-III) occurred predominantly in the very low density lipoprotein fraction (VLDL). This patient had normal lipoprotein lipase activity but mild glucose intolerance. The second patient had a borderline high cholesterol level with normal plasma triglycerides and apolipoproteins, whereas the third patient appeared to have normal total cholesterol but slightly higher triglycerides with elevated plasma apolipoprotein E (ApoE). No striking differences were observed in the chemical composition of all lipoprotein subfractions between patients and controls except that the neutral lipid content of VLDL was higher in patients than in controls. The ApoB was initially normal in molecular weight but degraded faster than the controls during storage. The appearance of the major low density lipoprotein (LDL) fraction of the first two patients was opaque white, in contrast to clear yellow in the third patient and in the age- and diet-matched controls. This abnormal appearance of LDL in these patients was associated with low plasma levels of beta-carotene and ceruloplasmin. These findings suggest that decreased serum copper levels may be associated with lipid and lipoprotein abnormalities and may enhance lipid peroxidation of LDL accounting for the color change.(ABSTRACT TRUNCATED AT 250 WORDS)

Neonatal salt loss in the hypertensive form of congenital adrenal hyperplasia

The 11 beta-hydroxylase deficiency (11OHD) form of congenital adrenal hyperplasia is diagnosed infrequently during the newborn period. A child presumed to have the 21-hydroxylase deficiency form of congenital adrenal hyperplasia was studied extensively as an infant. The diagnosis was based on ambiguous genitalia, elevated 17-ketosteroids, evidence of urinary 11-ketopregnanetriol, and salt loss. Severe hypertension was detected at 11 years, and 11 beta-hydroxylase deficiency was confirmed with elevated plasma 11-deoxycorticosterone and 11-deoxycortisol, low cortisol, and normalization of blood pressure following glucocorticoid replacement. Impaired aldosterone biosynthesis and salt loss were demonstrated during dexamethasone therapy. Salt loss during infancy does not distinguish between the 11 beta- and 21-hydroxylase deficiency forms of congenital adrenal hyperplasia.

Prenatal diagnosis of congenital adrenal hyperplasia

The accurate prenatal diagnosis of 21-beta-hydroxylase deficiency, based on amniotic fluid levels of 17-hydroxyprogesterone, is documented for a fetus 14 1/2 weeks old. In addition, family HLA genotyping data are consistent with the purported linkage between the HLA locus and the locus for 21-beta-hydroxylase.