Saxagliptin Prevents Increased Coronary Vascular Stiffness in Aortic-Banded Mini Swine.

Increased peripheral conduit artery stiffness has been shown in patients with heart failure (HF) with preserved ejection fraction. However, it is unknown whether this phenomenon extends to the coronary vasculature. HF with preserved ejection fraction may be driven, in part, by coronary inflammation, and inhibition of the enzyme DPP-4 (dipeptidyl-peptidase 4) reduces inflammation and oxidative stress. The purpose of this study was to determine the effect of saxagliptin-a DPP-4 inhibitor-on coronary stiffness in aortic-banded mini swine. We hypothesized saxagliptin would prevent increased coronary artery stiffness in a translational swine model with cardiac features of HF with preserved ejection fraction by inhibiting perivascular adipose tissue inflammation. Yucatan mini swine were divided into 3 groups: control, aortic-banded untreated HF, and aortic-banded saxagliptin-treated HF. Ex vivo mechanical testing was performed on the left circumflex and right coronary arteries, and advanced glycation end product, NF-κB (nuclear factor-κB), and nitrotyrosine levels were measured. An increase in the coronary elastic modulus of HF animals was associated with increased vascular advanced glycation end products, NF-κB, and nitrotyrosine levels compared with control and prevented by saxagliptin treatment. Aortas from healthy mice were treated with media from swine perivascular adipose tissue culture to assess its role on vascular stiffening. Conditioned media from HF and saxagliptin-treated HF animals increased mouse aortic stiffness; however, only perivascular adipose tissue from the HF group showed increased advanced glycation end products and NF-κB levels. In conclusion, our data show increased coronary conduit vascular stiffness was prevented by saxagliptin and associated with decreased advanced glycation end products, NF-κB, and nitrotyrosine levels in a swine model with potential relevance to HF with preserved ejection fraction.

Saxagliptin and Tadalafil Differentially Alter Cyclic Guanosine Monophosphate (cGMP) Signaling and Left Ventricular Function in Aortic-Banded Mini-Swine.

BACKGROUND: Cyclic guanosine monophosphate-protein kinase G-phosphodiesterase 5 signaling may be disturbed in heart failure (HF) with preserved ejection fraction, contributing to cardiac remodeling and dysfunction. The purpose of this study was to manipulate cyclic guanosine monophosphate signaling using the dipeptidyl-peptidase 4 inhibitor saxagliptin and phosphodiesterase 5 inhibitor tadalafil. We hypothesized that preservation of cyclic guanosine monophosphate cGMP signaling would attenuate pathological cardiac remodeling and improve left ventricular (LV) function. METHODS AND RESULTS: We assessed LV hypertrophy and function at the organ and cellular level in aortic-banded pigs. Concentric hypertrophy was equal in all groups, but LV collagen deposition was increased in only HF animals. Prevention of fibrotic remodeling by saxagliptin and tadalafil was correlated with neuropeptide Y plasma levels. Saxagliptin better preserved integrated LV systolic and diastolic function by maintaining normal LV chamber volumes and contractility (end-systolic pressure-volume relationship, preload recruitable SW) while preventing changes to early/late diastolic longitudinal strain rate. Function was similar to the HF group in tadalafil-treated animals including increased LV contractility, reduced chamber volume, and decreased longitudinal, circumferential, and radial mechanics. Saxagliptin and tadalafil prevented a negative cardiomyocyte shortening-frequency relationship observed in HF animals. Saxagliptin increased phosphodiesterase 5 activity while tadalafil increased cyclic guanosine monophosphate levels; however, neither drug increased downstream PKG activity. Early mitochondrial dysfunction, evident as decreased calcium-retention capacity and Complex II-dependent respiratory control, was present in both HF and tadalafil-treated animals. CONCLUSIONS: Both saxagliptin and tadalafil prevented increased LV collagen deposition in a manner related to the attenuation of increased plasma neuropeptide Y levels. Saxagliptin appears superior for treating heart failure with preserved ejection fraction, considering its comprehensive effects on integrated LV systolic and diastolic function.

Saxagliptin efficacy and safety in patients with type 2 diabetes mellitus stratified by cardiovascular disease history and cardiovascular risk factors: analysis of 3 clinical trials.

OBJECTIVE: To test the effectiveness and safety of saxagliptin 5 mg/d in patients with type 2 diabetes mellitus (T2DM) with and without history of cardiovascular disease (CVD) or cardiovascular (CV) risk factors. METHODS: The authors conducted a post hoc analysis of data from 3 randomized studies that compared saxagliptin versus placebo as initial combination therapy with metformin for 24 weeks (N = 648) and versus placebo as an add-on to insulin with and without metformin for 24 weeks (N = 455), and assessed noninferiority to glipizide as an add-on to metformin for 52 weeks (N = 858). Efficacy outcomes were the adjusted mean change from baseline in glycated hemoglobin (HbA1c) level, fasting plasma glucose concentration, and body weight and the proportion of patients achieving an HbA1c level < 7%. Pairwise comparisons were performed in subgroups with 1) history/no history of CVD, 2) ≥ 2 versus 0 to 1 CV risk factors, 3) hypertension/no hypertension, and 4) statin use/no statin use. Adverse events (AE) and hypoglycemia were monitored. RESULTS: In the initial combination therapy study, reductions in HbA1c level from baseline were greater with saxagliptin versus placebo in all subgroups (difference [saxagliptin - placebo], -0.38% to -0.67%). In the add-on to insulin ± metformin study, differences in adjusted mean change in HbA1c level versus placebo ranged from -0.23% to -0.58% across subgroups. In the noninferiority to glipizide study, adjusted mean changes in HbA1c level were comparable between saxagliptin and glipizide, across subgroups (difference, 0.08%-0.21%). No evidence suggested clinically relevant treatment-by-subgroup interactions in pairwise comparison. Incidences of ≥ 1 AE were comparable across subgroups. Incidences of confirmed hypoglycemia with saxagliptin were 0 in both metformin add-on studies and 1.2% to 7.8% with saxagliptin + insulin ± metformin. CONCLUSION: In patients with T2DM, saxagliptin 5 mg/d was similarly effective in improving glycemic control, with an AE profile similar to that of placebo, irrespective of CVD history, number of CV risk factors, hypertension, or statin use. TRIAL REGISTRATION: www.ClinicalTrials.gov identifiers: NCT00327015, NCT00575588, NCT00757588.

Saxagliptin versus glipizide as add-on therapy to metformin: assessment of hypoglycemia.

OBJECTIVE: To compare characteristics of hypoglycemic episodes in patients with type 2 diabetes receiving saxagliptin or glipizide add-on therapy to metformin. PATIENTS AND METHODS: This was a post hoc analysis of an international, randomized, parallel-group, double-blind, active-controlled, phase 3 trial. The 52-week trial and 52-week extension were conducted from December 2007 to August 2010. Patients aged ≥18 years with glycated hemoglobin (HbA1c) >6.5% to 10.0% receiving stable metformin doses (≥1500 mg/d) were randomized 1:1 to add-on therapy with saxagliptin 5 mg/d or glipizide 5 to 20 mg/d (titrated to optimal effect or highest tolerable dose during the initial 18 weeks). Hypoglycemic episodes were recorded in patient diaries. Confirmed hypoglycemic events were defined as fingerstick glucose ≤50 mg/dL (≤2.8 mmol/L) with associated symptoms. RESULTS: Of 858 patients randomized, 428 received saxagliptin + metformin, and 430 received glipizide + metformin. Saxagliptin was noninferior to glipizide in lowering HbA1c. Hypoglycemia with saxagliptin + metformin and glipizide + metformin was reported by 15 (24 events) and 165 (896 events) patients, respectively, through week 104. The mean (SD) number of hypoglycemic events per patient reporting hypoglycemia was lower with saxagliptin + metformin versus glipizide + metformin through weeks 52 (1.5 [SD 0.88] vs 4.8 [SD 4.9], respectively) and 104 (1.6 [SD 0.99] vs 5.4 [SD 5.8]). Most patients receiving glipizide + metformin with hypoglycemia had multiple events (124/165 patients [75%]). Confirmed hypoglycemia, major events, and severe events occurred only with glipizide + metformin. Time to first hypoglycemic event was shorter with glipizide versus saxagliptin. Limitations of this analysis include its post hoc nature, a high rate of study discontinuation, and exclusion of patients with serious comorbidities and complications. CONCLUSION: Saxagliptin + metformin was associated with fewer patients reporting hypoglycemia and fewer and less severe hypoglycemic events in those experiencing hypoglycemia compared with glipizide + metformin. ClinicalTrials.gov registration number: NCT00575588.

Safety and immunogenicity of a modified process hepatitis B vaccine in healthy neonates.

BACKGROUND: A manufacturing process using a modified adjuvant was developed to optimize the consistency and immunogenicity for recombinant hepatitis B vaccine (control: RECOMBIVAX-HB™). This modified process hepatitis B vaccine (mpHBV), which was previously shown to have an acceptable safety and immunogenicity profile in young adults, has now been studied in newborn infants. METHODS: Healthy 1-10-day-old neonates (N=566) received 3 intramuscular doses (5µg hepatitis B surface antigen [HBsAg] per dose) of either mpHBV or control at Day 1, and Months 1 and 6. Serum antibody to HBsAg (anti-HBs) was assayed at Month 7 (1 month Postdose 3). Anti-HBs geometric mean titers (GMTs) and seroprotection rates (SPRs) (% of subjects with an anti-HBs titer ≥10mIU/mL) were compared at Month 7. After each dose, injection-site adverse experiences (AEs) and axillary temperatures were recorded for 5 days; systemic AEs were recorded for Days 1-14. RESULTS: Month 7 SPR was 97.9% for the mpHBV group and 98.9% for the control. The GMT was 843.7mIU/mL for the mpHBV group and 670.1mIU/mL for the control. The GMT ratio (mpHBV/control) was 1.26 (95% confidence interval [CI]: 0.94, 1.69), meeting the prespecified non-inferiority criteria. The percentages of subjects reporting any AE, injection-site AEs, or systemic AEs were similar across the 2 vaccination groups. There were no serious AEs. CONCLUSIONS: The safety profile of mpHBV was comparable to that of the control vaccine. The geometric mean antibody titer for mpHBV was higher than control vaccine in this infant population, but the difference did not meet the predefined statistical criterion for superiority.

Safety, tolerability and immunogenicity of a recombinant hepatitis B vaccine manufactured by a modified process in healthy young adults.

BACKGROUND: Merck has developed a manufacturing process modification for RECOMBIVAX HB. Three lots of modified process hepatitis B vaccine (mpHBV) were studied in a randomized, blinded trial to demonstrate similarity of the three lots of mpHBV and noninferiority to RECOMBIVAX HB (control vaccine) with regard to immunogenicity. RESULTS: Month 7 SPRs for the mpHBV groups ranged from 97.8 to 98.9% (98.2% for the mpHBV groups combined). The seroprotection rate (SPR) for the control group was 98.5%. The estimated geometric mean titer (GMT) was 1761 mIU/mL for the mpHBV groups combined and 1108 mIU/mL for the control group. The GMT ratio (mpHBV/control) was 1.6 [95% confidence interval (CI): 1.2 to 2.1], indicating superiority of mpHBV compared with control. The percentages of subjects reporting any adverse experience (AE), injection-site AEs, or systemic AEs were similar across the four vaccination groups. There were no serious AEs. METHODS: Healthy 20-to 35-year-old subjects (N = 860) received a 1-mL intramuscular dose [10 mcg hepatitis B surface antigen (HBsAg)] of mpHBV from 1 of 3 lots or control at Day 1, and Months 1 and 6. Serum antibody to HBsAg (anti-HBs) was assayed Predose 1 and 1 month Postdose 3 (Month 7) using a quantitative hepatitis B antibody assay (Ortho VITROS ECi assay). Anti-HBs GMTs and SPRs (% of subjects with an anti-HBs titer > or =10 mIU/mL) were compared at Month 7. After each dose, injection-site AEs and oral temperature were recorded for 5 days; systemic AEs were recorded for 15 days. CONCLUSIONS: The SPRs for the mpHBV groups and the control group were high; responses were consistent across the mpHBV groups. The mpHBV and control vaccines were generally well tolerated.