Drug used in diabetes. Dipeptidyl peptidase 4 (DPP-4) inhibitors. ATC code:
Pharmacology: Pharmacodynamics: Mechanism of action:
Saxagliptin is a highly potent (Ki: 1.3 nM), selective, reversible, competitive DPP-4 inhibitor. In patients with type 2 diabetes, administration of saxagliptin led to inhibition of DPP-4 enzyme activity for a 24-hour period. After an oral glucose load, this DPP-4 inhibition resulted in a 2-to 3-fold increase in circulating levels of active incretin hormones, including glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP), decreased glucagon concentrations and increased glucose-dependent beta-cell responsiveness, which resulted in higher insulin and C-peptide concentrations. The rise in insulin from pancreatic beta-cells and the decrease in glucagon from pancreatic alpha-cells were associated with lower fasting glucose concentrations and reduced glucose excursion following an oral glucose load or a meal. Saxagliptin improves glycaemic control by reducing fasting and postprandial glucose concentrations in patients with type 2 diabetes.
Clinical safety and efficacy:
A total of 4,148 patients with type 2 diabetes, including 3,021 patients treated with, saxagliptin were randomised in 6 double-blind, controlled clinical safety and efficacy studies conducted to evaluate the effects of saxagliptin on glycaemic control. In these studies 634 patients were 65 years and older, while 59 patients were 75 years and older. Treatment with saxagliptin 5 mg once daily produced clinically relevant and statistically significant improvements in haemoglobin A1c (HbA1c), fasting plasma glucose (FPG) and postprandial glucose (PPG) compared to placebo in monotherapy, in combination with metformin (initial or add-on therapy), in combination with a sulphonylurea, and in combination with a thiazolidinedione (see Table 1). There was also no apparent change in body weight associated with saxagliptin. Reductions in HbA1c were seen across subgroups including gender, age, race, and baseline body mass index (BMI) and higher baseline HbA1c was associated with a greater adjusted mean change from baseline with saxagliptin.
Saxagliptin add-on to metformin therapy: An add-on to metformin placebo-controlled study of 24-week duration was conducted to evaluate the efficacy and safety of saxagliptin in combination with metformin in patients with inadequate glycaemic control (HbA1c 7-10%) on metformin alone. Saxagliptin (n=186) provided significant improvements in HbA1c, FPG and PPG compared to placebo (n=175). Improvements in HbA1c, PPG, and FPG following treatment with saxagliptin 5 mg plus metformin were sustained up to Week 102. The HbA1c change for saxagliptin 5 mg plus metformin (n=31) compared to placebo plus metformin (n=15) was -0.8% at Week 102.
Saxagliptin add-on to metformin compared with SU add-on to metformin: A 52-week study was conducted to evaluate the efficacy and safety of saxagliptin 5 mg in combination with metformin (428 patients) compared with sulphonylurea (glipizide, 5 mg titrated as needed to 20 mg, mean dose of 15 mg) in combination with metformin (430 patients) in 858 patients with inadequate glycaemic control (HbA1c 6.5%-10%) on metformin alone. The mean metformin dose was approximately 1900 mg in each treatment group. After 52 weeks, the saxagliptin and glipizide groups had similar mean reductions from baseline in HbA1c in the per-protocol analysis (-0.7% vs. -0.8%, respectively, mean baseline HbA1c of 7.5% for both groups). The intent-to-treat analysis showed consistent results. The reduction in FPG was slightly less in the saxagliptin-group and there were more discontinuations (3.5% vs. 1.2%) due to lack of efficacy based on FPG criteria during the first 24 weeks of the study. Saxagliptin also resulted in a significantly lower proportion of patients with hypoglycaemia, 3% (19 events in 13 subjects) vs. 36.3% (750 events in 156 patients) for glipizide. Patients treated with saxagliptin exhibited a significant decrease from baseline in body weight compared to a weight gain in patients administered glipizide (-1.1 vs. +1.1 kg).
Saxagliptin add-on to metformin compared with sitagliptin add-on to metformin: An 18-week study was conducted to evaluate the efficacy and safety of saxagliptin 5 mg in combination with metformin (403 patients), compared with sitagliptin 100 mg in combination with metformin (398 patients) in 801 patients with inadequate glycaemic control on metformin alone. After 18 weeks, saxagliptin was non-inferior to sitagliptin in mean reduction from baseline in HbA1c in both the per-protocol and the full analysis sets. The reductions from baseline in HbA1c respectively for saxagliptin and sitagliptin in the primary per-protocol analysis were -0.5% (mean and median) and -0.6% (mean and median). In the confirmatory full analysis set, mean reductions were -0.4% and -0.6% respectively for saxagliptin and sitagliptin, with median reductions of -0.5% for both groups.
Saxagliptin add-on combination therapy with insulin (with or without metformin): A total of 455 patients with type 2 diabetes participated in a 24-week randomised, double-blind, placebo-controlled study to evaluate the efficacy and safety of saxagliptin in combination with a stable dose of insulin (baseline mean: 54.2 Units) in patients with inadequate glycaemic control (HbA1c ≥7.5% and ≤11%) on insulin alone (n=141) or on insulin in combination with a stable dose of metformin (n=314). Saxagliptin 5 mg add-on to insulin with or without metformin provided significant improvements after 24 weeks in HbA1c and PPG compared with placebo add-on to insulin with or without metformin. Similar HbA1c reductions versus placebo were achieved for patients receiving saxagliptin 5 mg add-on to insulin regardless of metformin use (-0.4% for both subgroups). Improvements from baseline HbA1c were sustained in the saxagliptin add-on to insulin group compared to the placebo add-on to insulin group with or without metformin at Week 52. The HbA1c change for the saxagliptin group (n=244) compared to placebo (n=124) was -0.4% at Week 52.
Saxagliptin add-on to glibenclamide therapy: An add-on placebo-controlled study of 24-week duration was conducted to evaluate the efficacy and safety of saxagliptin in combination with glibenclamide in patients with inadequate glycaemic control at enrolment (HbA1c 7.5-10%) on a sub-maximal dose of glibenclamide alone. Saxagliptin in combination with a fixed, intermediate dose of a sulphonylurea (glibenclamide 7.5 mg) was compared to titration to a higher dose of glibenclamide (approximately 92% of patients in the placebo plus glibenclamide group were up-titrated to a final total daily dose of 15 mg). Saxagliptin (n=250) provided significant improvements in HbA1c, FPG and PPG compared to titration to a higher dose of glibenclamide (n=264).
Saxagliptin add-on to thiazolidinedione therapy: A placebo-controlled study of 24-week duration was conducted to evaluate the efficacy and safety of saxagliptin in combination with a thiazolidinedione (TZD) in patients with inadequate glycaemic control (HbA1c 7-10.5%) on TZD alone.
Patients with renal impairment: A 12-week, multi-centre, randomised, double-blind, placebo-controlled study was conducted to evaluate the treatment effect of saxagliptin 2.5 mg once daily compared with placebo in 170 patients (85 patients on saxagliptin and 85 on placebo) with type 2 diabetes (HbA1c 7.0-11%) and renal impairment (moderate [N=90]; severe [N=41]; or ESRD [N=39]). In this study, 98.2% of the patients were treated with other antihyperglycaemic medication (75.3% on insulin and 31.2% on oral antihyperglycaemic drugs; some received both). Saxagliptin significantly decreased HbA1c compared with placebo; the HbA1c change for saxagliptin was -0.9% at Week 12 (HbA1c change of -0.4% for placebo). Improvements in HbA1c following treatment with saxagliptin 2.5 mg were sustained up to Week 52, however the number of patients who completed 52 weeks without modification of other antihyperglycaemic medications was low (26 subjects in the saxagliptin group versus 34 subjects in the placebo group). The incidence of confirmed hypoglycaemic events was somewhat higher in the saxagliptin group (9.4%) versus placebo group (4.7%) although the number of subjects with any hypoglycaemic event did not differ between the treatment groups. There was no adverse effect on renal function as determined by estimated glomerular filtration rate or CrCL at Week 12 and Week 52. (See Table 1.)
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Saxagliptin add-on combination therapy with metformin plus sulfonylurea: A total of 257 patients with type 2 diabetes participated in this 24-week, randomized, doubleblind, placebo-controlled study to evaluate the efficacy and safety of saxagliptin (5 mg once daily) in combination with metformin plus sulfonylurea (SU) in patients with inadequate glycemic control (HbA1C and PPG compared with the placebo (n=128). The HbA1C change for saxagliptin compared to placebo was -0.7% at week 24.
Cardiovascular safety: The SAVOR trial included 8240 patients treated with ONGLYZA once daily and 8173 patients on placebo. The mean duration of ONGLYZA exposure regardless of interruptions was 1.8 years. A total of 3698 subjects (45%) were treated with ONGLYZA for between 2 and 3 years.
The primary safety and efficacy endpoint was a composite endpoint consisting of the time-to first occurrence of any of the following major adverse CV events (MACE): CV death, nonfatal myocardial infarction, or nonfatal ischemic stroke.
The primary safety objective of this trial was to establish that the upper bound of the 2-sided 95% CI for the estimated risk ratio comparing the incidence of the composite endpoint of CV death, non-fatal MI or non-fatal ischemic stroke observed with saxagliptin to that observed in the placebo group was <1.3.
The primary efficacy objective was to determine, as a superiority assessment, whether treatment with saxagliptin, compared with placebo when added to current background therapy, resulted in a significant reduction in the primary MACE endpoint.
The first secondary efficacy endpoint was a composite endpoint consisting of the time-to-first occurrence of MACE plus hospitalization for heart failure, hospitalization for unstable angina pectoris, or hospitalization for coronary revascularization (MACE plus). The next secondary efficacy endpoint was to determine whether treatment with saxagliptin compared with placebo when added to current background therapy in subjects with T2DM would result in a reduction of all-cause mortality.
SAVOR established the CV safety of saxagliptin, as CV risk (CV death, nonfatal myocardial infarction, or nonfatal ischemic stroke) was not increased in patients with T2DM compared to placebo when added to current background therapy (HR 1.00; 95% CI: 0.89, 1.12; P<0.001 for noninferiority).
The primary efficacy endpoint did not demonstrate a statistically significant difference in major adverse CV events for saxagliptin compared to placebo when added to current background therapy in patients with T2DM. (See Table 2 and Figure.)
Click on icon to see table/diagram/image
Click on icon to see table/diagram/image
Events accumulated consistently over time, and the event rates for TRADEMARK and placebo did not diverge notably over time.
One component of the secondary composite endpoint, hospitalization for heart failure, occurred at a greater rate in the saxagliptin group (3.5%) compared with the placebo group (2.8%), with nominal statistical significance (ie, without adjustment for testing of multiple endpoints) favouring placebo [HR = 1.27; (95% CI 1.07, 1.51); P = 0.007]. Clinically relevant factors predictive of increased relative risk with saxagliptin treatment could not be definitively identified. Subjects at higher risk for hospitalization for heart failure, irrespective of treatment assignment, could be identified by known risk factors for heart failure such as baseline history of heart failure or impaired renal function. However, subjects on saxagliptin with a history of heart failure or impaired renal function at baseline were not at an increased risk relative to placebo for the primary or secondary composite endpoints or all-cause mortality.
No increased risk for the primary endpoint was observed between saxagliptin and placebo in any of the following subgroups: CVD, multiple risk factors for CVD, mild, moderate, or severe renal impairment, age, gender, race, region, duration of type 2 diabetes, history of heart failure, baseline A1C, albumin/creatinine ratio, baseline antidiabetic medication, or baseline use of statins, aspirin, ACE inhibitors, ARBs, beta-blockers, or antiplatelet medications.
Despite active management of concomitant antidiabetic therapy in both study arms, mean A1C levels were lower in the saxagliptin group compared to the placebo group at Year 1 (7.6% versus 7.9%, difference of -0.35% [95% CI: -0.38, -0.31]) and at Year 2 (7.6% versus 7.9%, difference of -0.30% [95% CI: -0.34, -0.26]). The proportions of subjects with A1C <7% in the saxagliptin group compared to the placebo group were 38% versus 27% at Year 1 and 38% versus 29% at Year 2.
Compared to placebo, saxagliptin resulted in less need for the initiation of new or increases in current oral diabetes medications or insulin. The improvements in A1C and the proportion of subjects reaching A1C targets among saxagliptin-treated subjects were observed despite lower rates of upward adjustments in diabetes medications or initiation of new diabetes medications or insulin compared with placebo.
The pharmacokinetics of saxagliptin and its major metabolite were similar in healthy subjects and in patients with type 2 diabetes.
Saxagliptin was rapidly absorbed after oral administration in the fasted state, with maximum plasma concentrations (Cmax
) of saxagliptin and its major metabolite attained within 2 and 4 hours (Tmax
), respectively. The Cmax
and AUC values of saxagliptin and its major metabolite increased proportionally with the increment in the saxagliptin dose, and this dose-proportionality was observed in doses up to 400 mg. Following a 5 mg single oral dose of saxagliptin to healthy subjects, the mean plasma AUC values for saxagliptin and its major metabolite were 78 ng·h/ml and 214 ng·h/ml, respectively. The corresponding plasma Cmax
values were 24 ng/ml and 47 ng/ml, respectively. The intra-subject coefficients of variation for saxagliptin Cmax
and AUC were less than 12%.
The inhibition of plasma DPP-4 activity by saxagliptin for at least 24 hours after oral administration of saxagliptin is due to high potency, high affinity, and extended binding to the active site.
Interaction with food: Food had relatively modest effects on the pharmacokinetics of saxagliptin in healthy subjects. Administration with food (a high-fat meal) resulted in no change in saxagliptin Cmax
and a 27% increase in AUC compared with the fasted state. The time for saxagliptin to reach Cmax
) was increased by approximately 0.5 hours with food compared with the fasted state. These changes were not considered to be clinically meaningful.
The in vitro
protein binding of saxagliptin and its major metabolite in human serum is negligible. Thus, changes in blood protein levels in various disease states (e.g., renal or hepatic impairment) are not expected to alter the disposition of saxagliptin.
The biotransformation of saxagliptin is primarily mediated by cytochrome P450 3A4/5 (CYP3A4/5). The major metabolite of saxagliptin is also a selective, reversible, competitive DPP-4 inhibitor, half as potent as saxagliptin.
The mean plasma terminal half-life (t½
) values for saxagliptin and its major metabolite are 2.5 hours and 3.1 hours respectively, and the mean t½
value for plasma DPP-4 inhibition was 26.9 hours. Saxagliptin is eliminated by both renal and hepatic pathways. Following a single 50 mg dose of 14
C-saxagliptin, 24%, 36%, and 75% of the dose was excreted in the urine as saxagliptin, its major metabolite, and total radioactivity respectively. The average renal clearance of saxagliptin (~230 ml/min) was greater than the average estimated glomerular filtration rate (~120 ml/min), suggesting some active renal excretion. For the major metabolite, renal clearance values were comparable to estimated glomerular filtration rate. A total of 22% of the administered radioactivity was recovered in faeces representing the fraction of the saxagliptin dose excreted in bile and/or unabsorbed medicinal product from the gastrointestinal tract.
and AUC of saxagliptin and its major metabolite increased proportionally to the saxagliptin dose. No appreciable accumulation of either saxagliptin or its major metabolite was observed with repeated once-daily dosing at any dose level. No dose- and time-dependence was observed in the clearance of saxagliptin and its major metabolite over 14 days of once-daily dosing with saxagliptin at doses ranging from 2.5 mg to 400 mg.
Renal impairment: A single-dose, open-label study was conducted to evaluate the pharmacokinetics of a 10 mg oral dose of saxagliptin in subjects with varying degrees of chronic renal impairment compared to subjects with normal renal function.
The study included patients with renal impairment classified on the basis of-creatinine clearance (based on the Cockcroft-Gault formula) as mild (>50 to ≤80 ml/min), moderate (≥30 to ≤50 ml/min), or severe (≤30 ml/min), as well as patients with ESRD on haemodialysis.
The degree of renal impairment did not affect the Cmax
of saxagliptin or its major metabolite. In subjects with mild renal impairment, the mean AUC values of saxagliptin and its major metabolite were 1.2- and 1.7- fold higher, respectively, than mean AUC values in subjects with normal renal function. Because increases of this magnitude are not clinically relevant, dose adjustment in patients with mild renal impairment is not recommended. In subjects with moderate or severe renal impairment or in subjects with ESRD on haemodialysis, the AUC values of saxagliptin and its major metabolite were up to 2.1- and 4.5-fold higher, respectively, than AUC values in subjects with normal renal function. The dose of ONGLYZA should be reduced to 2.5 mg once daily in patients with moderate renal impairment (see Dosage & Adminisration and Precautions).
Hepatic impairment: In subjects with mild (Child-Pugh Class A), moderate (Child-Pugh Class B), or severe (Child-Pugh Class C) hepatic impairment the exposures to saxagliptin were 1.1-, 1.4- and 1.8-fold higher, respectively, and the exposures to BMS-510849 were 22%, 7%, and 33% lower, respectively, than those observed in healthy subjects.
Elderly patients (≥65 years): Elderly (65-80 years) had about 60% higher saxagliptin AUC than young patients (18-40 years). This is not considered clinically meaningful, therefore, no dose adjustment for ONGLYZA is recommended on the basis of age alone.
Toxicology: Preclinical safety data:
In cynomolgus monkeys saxagliptin produced reversible skin lesions (scabs, ulcerations and necrosis) in extremities (tail, digits, scrotum and/or nose) at doses ≥3 mg/kg/day. The no effect level (NOEL) for the lesions is 1 and 2 times the human exposure of saxagliptin and the major metabolite respectively, at the recommended human dose of 5 mg/day (RHD). The clinical relevance of the skin lesions is not known, however clinical correlates to skin lesions in monkeys have not been observed in human clinical trials of saxagliptin. Immune related findings of minimal, nonprogressive, lymphoid hyperplasia in spleen, lymph nodes and bone marrow with no adverse sequelae have been reported in all species tested at exposures starting from 7 times the RHD.
Saxagliptin produced gastrointestinal toxicity in dogs, including bloody/mucoid faeces and enteropathy at higher doses with a NOEL 4 and 2 times the human exposure for saxagliptin and the major metabolite, respectively, at RHD.
Saxagliptin was not genotoxic in a conventional battery of genotoxicity studies in vitro
and in vivo
. No carcinogenic potential was observed in two-year carcinogenicity assays with mice and rats.
Effects on fertility were observed in male and female rats at high doses producing overt signs of toxicity. Saxagliptin was not teratogenic at any doses evaluated in rats or rabbits. At high doses in rats, saxagliptin caused reduced ossification (a developmental delay) of the foetal pelvis and decreased foetal body weight (in the presence of maternal toxicity), with a NOEL 303 and 30 times the human exposure for saxagliptin and the major metabolite, respectively, at RHD. In rabbits, the effects of saxagliptin were limited to minor skeletal variations observed only at maternally toxic doses (NOEL 158 and 224 times the human exposure for saxagliptin and the major metabolite, respectively at RHD). In a pre- and postnatal developmental study in rats, saxagliptin caused decreased pup weight at maternally toxic doses, with NOEL 488 and 45 times the human exposure for saxagliptin and the major metabolite, respectively at RHD The effect on offspring body weights were noted until postnatal day 92 and 120 in females and males, respectively.