Pantoprazole Sodium 40 mg/10mL Injection, Powder, Lyophilized, For Solution — NDC 65219-385-10 (Billing 65219-0385-10)

12 CLINICAL PHARMACOLOGY

12.1Mechanism of Action Pantoprazole is a PPI that suppresses the final step in gastric acid production by covalently binding to the (H + , K + )-ATPase enzyme system at the secretory surface of the gastric parietal cell. This effect leads to inhibition of both basal and stimulated gastric acid secretion irrespective of the stimulus. The binding to the (H + , K + )-ATPase results in a duration of antisecretory effect that persists longer than 24 hours for all doses tested (20 mg to 120 mg).

12.2Pharmacodynamics Antisecretory Activity The magnitude and time course for inhibition of pentagastrin-stimulated acid output (PSAO) by single intravenous doses (20 to 120 mg) of pantoprazole were assessed in a single-dose, open-label, placebo-controlled, dose-response study. The results of this study are shown in Table 3. Healthy subjects received a continuous infusion for 25 hours of pentagastrin (PG) at 1 mcg/kg/hour, a dose known to produce submaximal gastric acid secretion.

The placebo group showed a sustained, continuous acid output for 25 hours, validating the reliability of the testing model. Intravenous administration of pantoprazole sodium had an onset of antisecretory activity within 15 to 30 minutes of administration. Intravenous doses of 20 to 80 mg of pantoprazole substantially reduced the 24-hour cumulative PSAO in a dose-dependent manner, despite a short plasma elimination half-life.

Complete suppression of PSAO was achieved with 80 mg within approximately 2 hours and no further significant suppression was seen with 120 mg. The duration of action of intravenous pantoprazole sodium was 24 hours. Table 3: Gastric Acid Output (mEq/hr, Mean ± SD) and Percent Inhibition*(Mean ± SD) of Pentagastrin-Stimulated Acid Output Over 24 Hours Following a Single Dose of Another Intravenous Pantoprazole Sodium † Product in Healthy Subjects 2 hours 4 hours 12 hours 24 hours Treatment Dose Acid Output % Inhibition Acid Output % Inhibition Acid Output % Inhibition Acid Output % Inhibition 0 mg (Placebo, n=4) 39 ± 21 NA 26 ± 14 NA 32 ± 20 NA 38 ± 24 NA 20 mg (n=4 to 6) 13 ± 18 47 ± 27 6 ± 8 83 ± 21 20 ± 20 54 ± 44 30 ± 23 45 ± 43 40 mg (n=8) 5 ± 5 82 ± 11 4 ± 4 90 ± 11 11 ± 10 81 ± 13 16 ± 12 52 ± 36 80 mg (n=8) 0.1 ± 0.2 96 ± 6 0.3 ± 0.4 99 ± 1 2 ± 2 90 ± 7 7 ± 4 63 ± 18 NA = not applicable. * Compared to individual subject baseline prior to treatment with intravenous pantoprazole sodium. † Inhibition of gastric acid output and the percent inhibition of stimulated acid output in response to intravenous pantoprazole sodium may be higher after repeated doses.

In one study of gastric pH in healthy subjects, pantoprazole was administered orally (40 mg enteric coated tablets) or intravenously (40 mg) once daily for 5 days and pH was measured for 24 hours following the fifth dose. The outcome measure was median percent of time that pH was ≥ 4 and the results were similar for intravenous and oral medications; however, the clinical significance of this parameter is unknown. Serum Gastrin Effects Serum gastrin concentrations were assessed in two placebo-controlled studies.

In a 5-day study of oral pantoprazole with 40 and 60 mg doses in healthy subjects, following the last dose on day 5, median 24-hour serum gastrin concentrations were elevated by 3 to 4 fold compared to placebo in both 40 and 60 mg dose groups. However, by 24 hours following the last dose, median serum gastrin concentrations for both groups returned to normal levels. In another placebo-controlled, 7-day study of 40 mg intravenous or oral pantoprazole in patients with GERD and a history of EE, the mean serum gastrin concentration increased approximately 50% from baseline and as compared with placebo, but remained within the normal range.

During 6 days of repeated administration of intravenous pantoprazole sodium in patients with ZE Syndrome, consistent changes of serum gastrin concentrations from baseline were not observed. Enterochromaffin-Like (ECL) Cell… [Excerpted — this section continues on DailyMed.]

12.1Mechanism of Action Pantoprazole is a PPI that suppresses the final step in gastric acid production by covalently binding to the (H + , K + )-ATPase enzyme system at the secretory surface of the gastric parietal cell. This effect leads to inhibition of both basal and stimulated gastric acid secretion irrespective of the stimulus. The binding to the (H + , K + )-ATPase results in a duration of antisecretory effect that persists longer than 24 hours for all doses tested (20 mg to 120 mg).

12.3Pharmacokinetics Pantoprazole peak serum concentration (C max ) and area under the serum concentration-time curve (AUC) increase in a manner proportional to intravenous doses of pantoprazole from 10 mg to 80 mg. Pantoprazole does not accumulate and its pharmacokinetics are unaltered with multiple daily dosing. Following the administration of intravenous pantoprazole sodium, the serum concentration of pantoprazole declines biexponentially with a terminal elimination half-life of approximately one hour.

In CYP2C19 extensive metabolizers [see Clinical Pharmacology (12.5) ] with normal liver function receiving a 40 mg intravenous dose of pantoprazole by constant rate over 15 minutes, the peak concentration (C max ) is 5.52 ± 1.42 mcg/mL and the total area under the plasma concentration versus time curve (AUC) is 5.4 ± 1.5 mcg•hr/mL. The total clearance is 7.6 to 14 L/h. Distribution The apparent volume of distribution of pantoprazole is approximately 11 to

23.6L, distributing mainly in extracellular fluid. The serum protein binding of pantoprazole is about 98%, primarily to albumin. Elimination Metabolism Pantoprazole is extensively metabolized in the liver through the cytochrome P450 (CYP) system.

Pantoprazole metabolism is independent of the route of administration (intravenous or oral). The main metabolic pathway is demethylation, by CYP2C19, with subsequent sulfation; other metabolic pathways include oxidation by CYP3A4. There is no evidence that any of the pantoprazole metabolites have significant pharmacologic activity.

CYP2C19 displays a known genetic polymorphism due to its deficiency in some sub-populations (e.g., 3% of Caucasians and African-Americans and 17 to 23% of Asians). Although these sub-populations of slow pantoprazole metabolizers have elimination half-life values from 3.5 to 10 hours, they still have minimal accumulation (23% or less) with once daily dosing. Excretion After administration of a single intravenous dose of 14 C-labeled pantoprazole sodium to healthy, extensive CYP2C19 metabolizers, approximately 71% of the dose was excreted in the urine with 18% excreted in the feces through biliary excretion.

There was no renal excretion of unchanged pantoprazole. Specific Populations Geriatric Patients After repeated intravenous administration in elderly subjects (65 to 76 years of age), the AUC and elimination half-life values of pantoprazole were similar to those observed in younger subjects. Male and Female Patients After oral administration there was a modest increase in the AUC and C max of pantoprazole in women compared to men.

However, weight-normalized clearance values are similar in women and men. Patients with Renal Impairment In patients with severe renal impairment, pharmacokinetic parameters for pantoprazole were similar to those of healthy subjects. Patients with Hepatic Impairment In patients with mild to severe hepatic impairment (Child-Pugh Class A to C), maximum pantoprazole concentrations increased only slightly (1.5-fold) relative to healthy subjects when pantoprazole sodium was administered orally.

Although serum half-life values increased to 7 to 9 hours and AUC values increased by 5- to 7-fold in hepatic-impaired patients, these increases were no greater than those observed in CYP2C19 poor metabolizers, where no dosage adjustment is warranted. These pharmacokinetic changes in hepatic-impaired patients result in minimal drug accumulation following once-daily, multiple-dose administration. Oral pantoprazole doses higher than 40 mg per day have not been studied in hepatically impaired patients.

Drug Interaction Studies Effect of Other Drugs on Pantoprazole Pantoprazole is metabolized mainly by CYP2C19 and to minor extents by CYPs 3A4, 2D6 and 2C9. In in vivo drug-drug interaction studies with CYP2C19 substrates (diazepam [also a CYP3A4 substrate] and phenytoin [also a CYP3A4 inducer]), nifedipine, midazolam, and clarithromycin (CYP3A4 substrates), metoprolol (a CYP2D6 substrate), diclo… [Excerpted — this section continues on DailyMed.]

12.2Pharmacodynamics Antisecretory Activity The magnitude and time course for inhibition of pentagastrin-stimulated acid output (PSAO) by single intravenous doses (20 to 120 mg) of pantoprazole were assessed in a single-dose, open-label, placebo-controlled, dose-response study. The results of this study are shown in Table 3. Healthy subjects received a continuous infusion for 25 hours of pentagastrin (PG) at 1 mcg/kg/hour, a dose known to produce submaximal gastric acid secretion.

The placebo group showed a sustained, continuous acid output for 25 hours, validating the reliability of the testing model. Intravenous administration of pantoprazole sodium had an onset of antisecretory activity within 15 to 30 minutes of administration. Intravenous doses of 20 to 80 mg of pantoprazole substantially reduced the 24-hour cumulative PSAO in a dose-dependent manner, despite a short plasma elimination half-life.

Complete suppression of PSAO was achieved with 80 mg within approximately 2 hours and no further significant suppression was seen with 120 mg. The duration of action of intravenous pantoprazole sodium was 24 hours. Table 3: Gastric Acid Output (mEq/hr, Mean ± SD) and Percent Inhibition*(Mean ± SD) of Pentagastrin-Stimulated Acid Output Over 24 Hours Following a Single Dose of Another Intravenous Pantoprazole Sodium † Product in Healthy Subjects 2 hours 4 hours 12 hours 24 hours Treatment Dose Acid Output % Inhibition Acid Output % Inhibition Acid Output % Inhibition Acid Output % Inhibition 0 mg (Placebo, n=4) 39 ± 21 NA 26 ± 14 NA 32 ± 20 NA 38 ± 24 NA 20 mg (n=4 to 6) 13 ± 18 47 ± 27 6 ± 8 83 ± 21 20 ± 20 54 ± 44 30 ± 23 45 ± 43 40 mg (n=8) 5 ± 5 82 ± 11 4 ± 4 90 ± 11 11 ± 10 81 ± 13 16 ± 12 52 ± 36 80 mg (n=8) 0.1 ± 0.2 96 ± 6 0.3 ± 0.4 99 ± 1 2 ± 2 90 ± 7 7 ± 4 63 ± 18 NA = not applicable. * Compared to individual subject baseline prior to treatment with intravenous pantoprazole sodium. † Inhibition of gastric acid output and the percent inhibition of stimulated acid output in response to intravenous pantoprazole sodium may be higher after repeated doses.

In one study of gastric pH in healthy subjects, pantoprazole was administered orally (40 mg enteric coated tablets) or intravenously (40 mg) once daily for 5 days and pH was measured for 24 hours following the fifth dose. The outcome measure was median percent of time that pH was ≥ 4 and the results were similar for intravenous and oral medications; however, the clinical significance of this parameter is unknown. Serum Gastrin Effects Serum gastrin concentrations were assessed in two placebo-controlled studies.

In a 5-day study of oral pantoprazole with 40 and 60 mg doses in healthy subjects, following the last dose on day 5, median 24-hour serum gastrin concentrations were elevated by 3 to 4 fold compared to placebo in both 40 and 60 mg dose groups. However, by 24 hours following the last dose, median serum gastrin concentrations for both groups returned to normal levels. In another placebo-controlled, 7-day study of 40 mg intravenous or oral pantoprazole in patients with GERD and a history of EE, the mean serum gastrin concentration increased approximately 50% from baseline and as compared with placebo, but remained within the normal range.

During 6 days of repeated administration of intravenous pantoprazole sodium in patients with ZE Syndrome, consistent changes of serum gastrin concentrations from baseline were not observed. Enterochromaffin-Like (ECL) Cell Effects There are no data available on the effects of intravenous pantoprazole sodium on ECL cells. In a nonclinical study in Sprague-Dawley rats, lifetime exposure (24 months) to oral pantoprazole at doses of 0.5 to 200 mg/kg/day resulted in dose-related increases in gastric ECL-cell proliferation and gastric neuroendocrine (NE)-cell tumors.

Gastric NE-cell tumors in rats may result from chronic elevation of serum gastrin concentrations. The high density of ECL cells in the rat stomach makes this species highly susc… [Excerpted — this section continues on DailyMed.]

14 CLINICAL STUDIES The safety and efficacy of Pantoprazole Sodium for Injection have been established based on adequate and well-controlled adult studies of another intravenous pantoprazole sodium product in GERD associated with a history of EE and pathological hypersecretory conditions, including Zollinger-Ellison syndrome. Below is a display of the results of these adequate and well-controlled studies of pantoprazole sodium in these conditions.

14.1Gastroesophageal Reflux Disease (GERD) Associated with a History of Erosive Esophagitis A multicenter, double-blind, two-period placebo-controlled study was conducted to assess the ability of pantoprazole sodium to maintain gastric acid suppression in patients switched from the oral dosage form to the intravenous dosage form. GERD patients (n=65, 26 to 64 years; 35 female; 9 Black, 11 Hispanic, 44 White, 1 other) with a history of EE were randomized to receive either 20 or 40 mg of oral pantoprazole once per day for 10 days (period 1), and then were switched in period 2 to either daily intravenous pantoprazole sodium or placebo for 7 days, matching their respective dose level from period 1.

Patients were administered all test medication with a light meal. Maximum acid output (MAO) and basal acid output (BAO) were determined 24 hours following the last day of oral medication (day 10), the first day (day 1) of intravenous administration and the last day of intravenous administration (day 7). MAO was estimated from a 1 hour continuous collection of gastric contents following subcutaneous injection of 6 mcg/kg of pentagastrin.

This study demonstrated that, after 10 days of repeated oral administration followed by 7 days of intravenous administration, the oral and intravenous dosage forms of pantoprazole 40 mg are similar in their ability to suppress MAO and BAO in patients with GERD and a history of erosive esophagitis (see Table 4). Also, patients on oral pantoprazole sodium who were switched to intravenous placebo experienced a significant increase in acid output within 48 hours of their last oral dose (see Table 4). However, at 48 hours after their last oral dose, patients treated with intravenous pantoprazole sodium had a significantly lower mean basal acid output (see Table 4) than those treated with placebo.

Table 4: Antisecretory Effects (mEq/h) of 40 mg Intravenous Pantoprazole Sodium and 40 mg Oral Pantoprazole in GERD Patients with a History of Erosive Esophagitis Parameter Pantoprazole Sodium Delayed-Release Tablets DAY 10 Intravenous Pantoprazole Sodium* DAY 7 Intravenous Placebo DAY 7 Mean maximum acid output Mean basal acid output 6.49 n=30 0.80 n=30 6.62 n=23 0.53 n=23 29.19** n=7 4.14** n=7 * another intravenous pantoprazole sodium product ** p<0.0001 Significantly different from intravenous pantoprazole sodium.

To evaluate the effectiveness of intravenous pantoprazole sodium as an initial treatment to suppress gastric acid secretion, two studies were conducted. Study 1 was a multicenter, double-blind, placebo-controlled, study of the pharmacodynamic effects of intravenous and oral pantoprazole sodium. Patients with GERD and a history of EE (n=78, 20 to 67 years; 39 females; 7 Black, 19 Hispanic, 52 White) were randomized to receive either 40 mg pantoprazole intravenously, 40 mg pantoprazole orally, or placebo once daily for 7 days.

Following an overnight fast, test medication was administered and patients were given a light meal within 15 minutes. MAO and BAO were determined 24 hours following the last day of study medication. MAO was estimated from a 1 hour continuous collection of gastric contents following subcutaneous injection of 6 mcg/kg of pentagastrin to stimulate acid secretion.

This study demonstrated that, after treatment for 7 days, patients treated with intravenous pantoprazole sodium had a significantly lower MAO and BAO than those treated with placebo (p<0.001), and results were comparable to those of patients treated with oral pantoprazole sodium (se… [Excerpted — this section continues on DailyMed.]

13 NONCLINICAL TOXICOLOGY

13.1Carcinogenesis, Mutagenesis, Impairment of Fertility In a 24-month carcinogenicity study, Sprague-Dawley rats were treated orally with pantoprazole doses of 0.5 to 200 mg/kg/day, about 0.1 to 40 times the exposure on a body surface area basis of a 50-kg person dosed at 40 mg/day. In the gastric fundus, treatment with 0.5 to 200 mg/kg/day produced enterochromaffin-like (ECL) cell hyperplasia and benign and malignant neuroendocrine cell tumors in a dose-related manner. In the forestomach, treatment with 50 and 200 mg/kg/day (about 10 and 40 times the recommended human dose on a body surface area basis) produced benign squamous cell papillomas and malignant squamous cell carcinomas.

Rare gastrointestinal tumors associated with pantoprazole treatment included an adenocarcinoma of the duodenum with 50 mg/kg/day and benign polyps and adenocarcinomas of the gastric fundus with 200 mg/kg/day. In the liver, treatment with 0.5 to 200 mg/kg/day produced dose-related increases in the incidences of hepatocellular adenomas and carcinomas. In the thyroid gland, treatment with 200 mg/kg/day produced increased incidences of follicular cell adenomas and carcinomas for both male and female rats.

In a 24-month carcinogenicity study, Fischer 344 rats were treated orally with pantoprazole doses of 5 to 50 mg/kg/day, approximately 1 to 10 times the recommended human dose based on body surface area. In the gastric fundus, treatment at 5 to 50 mg/kg/day produced enterochromaffin-like (ECL) cell hyperplasia and benign and malignant neuroendocrine cell tumors. Dose selection for this study may not have been adequate to comprehensively evaluate the carcinogenic potential of pantoprazole.

In a 24-month carcinogenicity study, B6C3F1 mice were treated orally with pantoprazole doses of 5 to 150 mg/kg/day, 0.5 to 15 times the recommended human dose based on body surface area. In the liver, treatment at 150 mg/kg/day produced increased incidences of hepatocellular adenomas and carcinomas in female mice. Treatment at 5 to 150 mg/kg/day also produced gastric fundic ECL cell hyperplasia.

A 26-week p53 +/- transgenic mouse carcinogenicity study was not positive. Pantoprazole was positive in the in vitro human lymphocyte chromosomal aberration assays, in one of two mouse micronucleus tests for clastogenic effects, and in the in vitro Chinese hamster ovarian cell/HGPRT forward mutation assay for mutagenic effects. Equivocal results were observed in the in vivo rat liver DNA covalent binding assay.

Pantoprazole was negative in the in vitro Ames mutation assay, the in vitro unscheduled DNA synthesis (UDS) assay with rat hepatocytes, the in vitro AS52/GPT mammalian cell-forward gene mutation assay, the in vitro thymidine kinase mutation test with mouse lymphoma L5178Y cells, and the in vivo rat bone marrow cell chromosomal aberration assay. There were no effects on fertility or reproductive performance when pantoprazole was given at oral doses up to 500 mg/kg/day in male rats (98 times the recommended human dose based on body surface area) and 450 mg/kg/day in female rats (88 times the recommended human dose based on body surface area).