Overall, the pharmacokinetics of dapagliflozin and saxagliptin were not affected in a clinically relevant manner when administered as dapagliflozin and saxagliptin.
Saxagliptin
The pharmacokinetics of saxagliptin and its active metabolite, 5-hydroxy saxagliptin, were similar in healthy subjects and in patients with type 2 diabetes mellitus. The Cmax and AUC values of saxagliptin and its active metabolite increased proportionally in the 2.5 to 400 mg dose range. Following a 5 mg single oral dose of saxagliptin to healthy subjects, the mean plasma AUC values for saxagliptin and its active 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 average variability (%CV) for AUC and Cmax for both saxagliptin and its active metabolite was less than 25%.
No appreciable accumulation of either saxagliptin or its active metabolite was observed with repeated once daily dosing at any dose level. No dose- and time-dependence were observed in the clearance of saxagliptin and its active metabolite over 14 days of once daily dosing with saxagliptin at doses ranging from 2.5 to 400 mg.
Absorption
Dapagliflozin
Following oral administration of dapagliflozin, the maximum plasma concentration (Cmax) is usually attained within 2 hours under fasting state. The Cmax and AUC values increase dose proportionally with increase in dapagliflozin dose in the therapeutic dose range. The absolute oral bioavailability of dapagliflozin following the administration of a 10 mg dose is 78%. Administration of dapagliflozin with a high-fat meal decreases its Cmax by up to 50% and prolongs Tmax by approximately 1 hour but does not alter AUC as compared with the fasted state.
Saxagliptin
The median time to maximum concentration (Tmax) following the 5 mg once daily dose was 2 hours for saxagliptin and 4 hours for its active metabolite. Administration with a high-fat meal resulted in an increase in Tmax of saxagliptin by approximately 20 minutes as compared to fasted conditions. There was a 27% increase in the AUC of saxagliptin when given with a meal as compared to fasted conditions.
Distribution
Dapagliflozin
Dapagliflozin is approximately 91% protein bound. Protein binding is not altered in patients with renal or hepatic impairment.
Saxagliptin
The in vitro protein binding of saxagliptin and its active metabolite in human serum is negligible. Therefore, changes in blood protein levels in various disease states (e.g., renal or hepatic impairment) are not expected to alter the disposition of saxagliptin.
Metabolism
Dapagliflozin
The metabolism of dapagliflozin is primarily mediated by UGT1A9; CYP-mediated metabolism is a minor clearance pathway in humans. Dapagliflozin is extensively metabolized, primarily to yield dapagliflozin 3-O-glucuronide, which is an inactive metabolite. Dapagliflozin 3-O-glucuronide accounted for 61% of a 50 mg [14C]-dapagliflozin dose and is the predominant drug-related component in human plasma.
Saxagliptin
The metabolism of saxagliptin is primarily mediated by cytochrome P450 3A4/5 (CYP3A4/5). The major metabolite of saxagliptin is also a DPP-4 inhibitor, which is one-half as potent as saxagliptin. Therefore, strong CYP3A4/5 inhibitors and inducers will alter the pharmacokinetics of saxagliptin and its active metabolite [see DRUG INTERACTIONS (7)].
Elimination
Dapagliflozin
Dapagliflozin and related metabolites are primarily eliminated via the renal pathway. Following a single 50 mg dose of [14C]-dapagliflozin, 75% and 21% total radioactivity is excreted in urine and feces, respectively. In urine, less than 2% of the dose is excreted as parent drug. In feces, approximately 15% of the dose is excreted as parent drug. The mean plasma terminal half-life (t1/2) for dapagliflozin is approximately 12.9 hours following a single oral dose of dapagliflozin 10 mg.
Saxagliptin
Saxagliptin is eliminated by both renal and hepatic pathways. Following a single 50 mg dose of [14C]-saxagliptin, 24%, 36%, and 75% of the dose was excreted in the urine as saxagliptin, its active 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. A total of 22% of the administered radioactivity was recovered in feces representing the fraction of the saxagliptin dose excreted in bile and/orunabsorbed drug from the gastrointestinal tract. Following a single oral dose of saxagliptin 5 mg to healthy subjects, the mean plasma terminal half-life (t1/2) for saxagliptin and its active metabolite was 2.5 and 3.1 hours, respectively.
Specific Populations
Effects of Age, Gender, Race and Body Weight on Pharmacokinetics
Based on a population pharmacokinetic analysis, age, gender, race, and body weight do not have a clinically meaningful effect on the pharmacokinetics of saxagliptin and dapagliflozin.
Renal Impairment
Dapagliflozin
At steady state (20 mg once daily dapagliflozin for 7 days), patients with type 2 diabetes mellitus with mild, moderate, or severe renal impairment (as determined by eGFR) had geometric mean systemic exposures of dapagliflozin that were 45%, 100%, and 200% higher, respectively, as compared to patients with type 2 diabetes mellitus with normal renal function. Higher systemic exposure of dapagliflozin in patients with type 2 diabetes mellitus with renal impairment did not result in a correspondingly higher 24-hour urinary glucose excretion. The steady-state 24-hour urinary glucose excretion in patients with type 2 diabetes mellitus and mild, moderate, and severe renal impairment was 42%, 80%, and 90% lower, respectively, than in patients with type 2 diabetes mellitus with normal renal function. The impact of hemodialysis on dapagliflozin exposure is not known [see DOSAGE AND ADMINISTRATION (2.3), WARNINGS AND PRECAUTIONS (5.4)and USE IN SPECIFIC POPULATIONS (8.6)].
Saxagliptin
A single-dose, open-label study was conducted to evaluate the pharmacokinetics of saxagliptin (10 mg dose) in subjects with varying degrees of chronic renal impairment compared to subjects with normal renal function. The 10 mg dosage is not an approved dosage. The degree of renal impairment did not affect Cmax of saxagliptin or its metabolite. In subjects with moderate renal impairment (eGFR 30 to less than 45 mL/min/1.73 m2), severe renal impairment (eGFR 15 to less than 30 mL/min/1.73 m2) and ESRD patient on hemodialysis, the AUC values of saxagliptin or its active metabolite were >2 fold higher than AUC values in subjects with normal renal function.Dapagliflozina and saxagliptin is contraindicated in patients with an eGFR <45 mL/min/1.73 m2.
Hepatic Impairment
Dapagliflozin
In subjects with mild and moderate hepatic impairment (Child-Pugh classes A and B), mean Cmax and AUC of dapagliflozin were up to 12% and 36% higher, respectively, as compared to healthy matched control subjects following single-dose administration of 10 mg dapagliflozin. These differences were not considered to be clinically meaningful. In patients with severe hepatic impairment (Child-Pugh class C), mean Cmax and AUC of dapagliflozin were up to 40% and 67% higher, respectively, as compared to healthy matched controls [see USE IN SPECIFIC POPULATIONS (8.7)].
Saxagliptin
In subjects with hepatic impairment (Child-Pugh classes A, B, and C), mean Cmax and AUC of saxagliptin were up to 8% and 77% higher, respectively, compared to healthy matched controls following administration of a single 10 mg dose of saxagliptin. The 10 mg dosage is not an approved dosage. The corresponding Cmax and AUC of the active metabolite were up to 59% and 33% lower, respectively, compared to healthy matched controls. These differences are not considered to be clinically meaningful.
Pediatric
Pharmacokinetics of dapagliflozin and saxagliptin in the pediatric population has not been studied.
Drug Interactions
Saxagliptin and Dapagliflozin
The lack of pharmacokinetic interaction between dapagliflozin and saxagliptin was demonstrated in a drug-drug interaction study between dapagliflozin and saxagliptin.
Dapagliflozin
In Vitro Assessment of Drug Interactions
The metabolism of dapagliflozin is primarily via glucuronide conjugation mediated by UDP glucuronosyltransferase 1A9 (UGT1A9).
In in vitro studies, dapagliflozin and dapagliflozin 3-O-glucuronide neither inhibited CYP 1A2, 2C9, 2C19, 2D6, or 3A4, nor induced CYP 1A2, 2B6, or 3A4. Dapagliflozin is a weak substrate of the P-glycoprotein (P-gp) active transporter, and dapagliflozin 3-O-glucuronide is a substrate for the OAT3 active transporter. Dapagliflozin or dapagliflozin 3-O-glucuronide did not meaningfully inhibit P-gp, OCT2, OAT1, or OAT3 active transporters. Overall, dapagliflozin is unlikely to affect the pharmacokinetics of concurrently administered medications that are P-gp, OCT2, OAT1, or OAT3 substrates.
Effects of Other Drugs on Dapagliflozin
Table 4 shows the effect of coadministered drugs on the pharmacokinetics of dapagliflozin.
Table 4: Effects of Coadministered Drugs on Dapagliflozin Systemic Exposure
Coadministered Drug (Dose Regimen)*
| Dapagliflozin (Dose Regimen)*
| Dapagliflozin |
Change†in AUC‡
| Change†in Cmax
|
Oral Antidiabetic Agents
|
Metformin (1,000 mg)
| 20 mg
| ↓1%
| ↓7%
|
Pioglitazone (45 mg)
| 50 mg
| 0%
| ↑9%
|
Sitagliptin (100 mg)
| 20 mg
| ↑8%
| ↓4%
|
Glimepiride (4 mg)
| 20 mg
| ↓1%
| ↑1%
|
Voglibose (0.2 mg three times daily)
| 10 mg
| ↑1%
| ↑4%
|
Saxagliptin (5 mg single dose)
| 10 mg (single dose)
| ↓2%
| ↓6%
|
Other Medications
|
Hydrochlorothiazide (25 mg)
| 50 mg
| ↑7%
| ↓1%
|
Bumetanide (1 mg)
| 10 mg once daily for 7 days
| ↑5%
| ↑8%
|
Valsartan (320 mg)
| 20 mg
| ↑2%
| ↓12%
|
Simvastatin (40 mg)
| 20 mg
| ↓1%
| ↓2%
|
Anti-infective Agent
|
|
|
|
Rifampin (600 mg once daily for 6 days) | 10 mg
| ↓22%
| ↓7%
|
Non-Steroidal Anti-inflammatory Agent
|
Mefenamic Acid (loading dose of 500 mg followed by 14 doses of 250 mg every 6 hours)
| 10 mg
| ↑51%
| ↑13%
|
*Single dose unless otherwise noted.
†Percent change (with/without coadministered drug and no change=0%); ↑ and ↓ indicate the exposure increase and decrease, respectively.
‡AUC=AUC(INF) for drugs given as single dose and AUC=AUC(TAU) for drugs given in multiple doses.
Effects of Dapagliflozin on Other Drugs
Table 5 shows the effect of dapagliflozin on other coadministered drugs. Dapagliflozin did not meaningfully affect the pharmacokinetics of the coadministered drugs