Bioequivalence and Bioavailability of an Orodispersible Tablet of Sildenafil Citrate in Healthy Chinese Male Subjects

In this trial, 27% of patients were <7 years old. Patients were WHO Functional Class I (32%), II (51%), III (15%), or IV (0.4%). Patients were naïve for specific PAH therapy and the use of prostacyclin, prostacyclin analogues and endothelin receptor antagonists were not permitted in the study, and neither were arginine supplementation, nitrates, alpha-blockers and potent CYP450 3A4 inhibitors. The primary objective of the study was to assess the effect of Sildenafil citrate on percent change from baseline in PVO2, normalized to body weight, from baseline to week 16 as measured by the Cardiopulmonary Exercise Test (CPET) (patients who were developmentally able to perform the test, n = 115). Secondary endpoints included hemodynamic monitoring, symptom assessment, WHO Functional Class, change in background treatment, and quality of life measurements (n = 234). Patients were allocated to one of three sildenafil treatment groups (low, medium, or high) or placebo. Actual doses administered were dependent on body weight (see Table 5). Treatment Allocation by Dose and Body Weight in Pediatric Study The proportion of patients receiving supportive medicinal products at baseline (anticoagulants, digoxin, calcium channel blockers, diuretics and/or oxygen) was similar in the combined sildenafil treatment group (48%) and the placebo treatment group (42%).

6.2 Post-marketing Experience

In this trial, 27% of patients were <7 years old. Patients were WHO Functional Class I (32%), II (51%), III (15%), or IV (0.4%). Patients were naïve for specific PAH therapy and the use of prostacyclin, prostacyclin analogues and endothelin receptor antagonists were not permitted in the study, and neither were arginine supplementation, nitrates, alpha-blockers and potent CYP450 3A4 inhibitors. The primary objective of the study was to assess the effect of Sildenafil citrate on percent change from baseline in PVO2, normalized to body weight, from baseline to week 16 as measured by the Cardiopulmonary Exercise Test (CPET) (patients who were developmentally able to perform the test, n = 115). Secondary endpoints included hemodynamic monitoring, symptom assessment, WHO Functional Class, change in background treatment, and quality of life measurements (n = 234).

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Patients were allocated to one of three sildenafil treatment groups (low, medium, or high) or placebo. Actual doses administered were dependent on body weight (see Table 5). Treatment Allocation by Dose and Body Weight in Pediatric Study The proportion of patients receiving supportive medicinal products at baseline (anticoagulants, digoxin, calcium channel blockers, diuretics and/or oxygen) was similar in the combined sildenafil treatment group (48%) and the placebo treatment group (42%). The primary endpoint was a percentage change in VO2peak from baseline to week 16 assessed by CPET. Mean baseline peak volume of oxygen consumed (VO2) values were similar across the sildenafil treatment groups (17 to 18 ml/kg/min), and slightly higher for the placebo treatment group (20 ml/kg/min).

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A total of 45% of patients were evaluable for CPET, which comprised those children ≥7 years old and developmentally able to perform the test. Children <7 years were evaluable only for the secondary endpoints. Mean increases in VO2peak percentage change from baseline at Week 16, were observed with all 3 sildenafil doses (range of 6% to 13%, Figure 6), with little change with placebo (0.5%). Percentage Change from Baseline in VO2Peak: Mean (95% Confidence Intervals) The estimated difference between the combined sildenafil doses and placebo was 8% (95% CI: 0.2 to 16). The results of the main analysis (combined dose groups versus placebo) were not statistically significant (p=0.056). The primary endpoint was a percentage change in VO2peak from baseline to week 16 assessed by CPET. Mean baseline peak volume of oxygen consumed (VO2) values were similar across the sildenafil treatment groups (17 to 18 ml/kg/min), and slightly higher for the placebo treatment group (20 ml/kg/min). A total of 45% of patients were evaluable for CPET, which comprised those children ≥7 years old and developmentally able to perform the test. Children <7 years were evaluable only for the secondary endpoints. Mean increases in VO2peak percentage change from baseline at Week 16, were observed with all 3 sildenafil doses (range of 6% to 13%, Figure 6), with little change with placebo (0.5%). Percentage Change from Baseline in VO2Peak: Mean (95% Confidence Intervals) The estimated difference between the combined sildenafil doses and placebo was 8% (95% CI: 0.2 to 16). The results of the main analysis (combined dose groups versus placebo) were not statistically significant (p=0.056). The estimated difference between the sildenafil medium dose group and placebo was 11±5% (95% CI: 2 to 21). Impact on Hemodynamic Parameters Dose related improvements were observed with PVRI and mPAP. Statistically significant PVRI reductions compared to placebo were seen with the sildenafil medium and high dose groups (18% [95% CI: -32% to -2%] and sildenafil 20 mg tablets 27% [95% CI: -39% to -14%], respectively) but not the low dose group (2% (95% CI: -20%, 20%). The sildenafil medium and high dose groups displayed mPAP changes from baseline compared to placebo, of -3.5 mmHg (95% CI: -8.9, 1.9) and -7.3 mmHg (95% CI: -12.4, -2.1), respectively; while the low dose group showed little difference from placebo (difference of 1.6 mmHg [95% CI: -4.5, 7.6]). Improvements were observed with cardiac index with all three sildenafil groups over placebo, 10%, 4%, and 15% for the low, medium, and high dose groups, respectively [see Clinical Pharmacology (12.2)]. STARTS-2 (NCT00159874) - Long-Term Survival with Oral Sildenafil Monotherapy in Treatment-Naïve Pediatric Pulmonary Arterial Hypertension Of the 234 pediatric patients treated in the short-term, placebo-controlled study, 220 patients entered the long-term extension study. Patients who had been in the placebo group in the short-term study were randomly reassigned to sildenafil treatment; patients weighing ≤20 kg entered the medium or high dose groups (1:2), while patients weighing >20 kg entered the low, medium, or high dose groups (1:1:1).

Of the total 229 patients who received sildenafil, there were 55, 74, and 100 patients in the low, medium, and high dose groups, respectively. Across the short-term and long-term studies, the overall duration of treatment from start of double-blind for individual patients ranged from 3 to 3,129 days. By sildenafil treatment group, median duration of sildenafil treatment was 1,696 days (excluding the 5 patients who received placebo in double-blind and were not treated in the long-term extension study). Peak VO2 was assessed 1 year after the start of the placebo-controlled study. Of sildenafil-treated patients developmentally able to perform the CPET 59/114 patients (52%) had not shown any deterioration in PVO2 from start of sildenafil.

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The study was a randomized, double-blind, parallel-group study in 385 adults with PAH. Patients were randomly assigned 1:1:1 to one of three treatment groups (5, 20, and 80 mg TID). Most patients were PAH treatment naïve (83%). For most patients the etiology of PAH was idiopathic (72%). The most common WHO Functional Class was Class III (58% of patients).

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Treatment groups were well balanced with respect to baseline demographics of strata history of PAH treatment and etiology of PAH, as well as the WHO Functional Class categories. The primary objective of the study was to compare sildenafil 80 mg TID versus 5 mg TID for mortality, with success defined by ruling out twice the mortality at 80 mg. The key secondary efficacy endpoint was time to first event of clinical worsening, defined as a composite endpoint of all-cause mortality, hospitalization for worsening PAH or disease progression. An additional secondary endpoint was 6MWD at Months 6 and 12. Overall Survival At the time of a planned interim analysis (50% deaths) it was identified that the primary efficacy objective of this protocol was met and therefore the study sildenafil for women was stopped.

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Based on the primary efficacy endpoint (mortality), the non-inferiority of sildenafil 80 mg TID arm versus 5 mg TID arm was met using a 2-sided significance level of 0.003 for the interim analysis. Primary comparison of the 80 mg TID group to the 5-mg TID group yielded the HR (99.7% CI) = 0.51 (0.22, 1.21); i.e., non-inferiority was established. Kaplan-Meier estimates of survival at 3 years were 66%, 79%, and 85% in the 5-, 20-, and 80mg TID dose groups, respectively Clinical Worsening Sildenafil 80 mg was also superior to 5 mg for time to first event of clinical worsening with HR (99.7% CI) = 0.44 (0.22, 0.89). At baseline, the median of 6MWD for the intent-to-treat (ITT) population was 332 to 352 m. At Month 6, the median change from baseline was highest for sildenafil 80 mg TID with 28 m compared to 18 m and 19 m for sildenafil 5 mg TID and sildenafil 20 mg TID groups, respectively. Similarly, 191 of 229 patients (83%) who had received sildenafil had either maintained or improved their WHO Functional Class at 1 year assessment. Kaplan-Meier estimates of survival at 3 years in patients >20 kg in weight at baseline were 94%, 93%, and 85% in the low, medium, and high dose groups, respectively; for patients ≤20 kg in weight at baseline, the survival estimates were 94% and 93% for patients in the medium and high dose groups, respectively [see Use in Specific Populations (8.4) and Adverse Reactions (6.1)]. Study A1481324 (NCT02060487) - Study to Assess the Effects of Sildenafil citrate on Mortality in Adults with PAH A study to assess the effects of multiple doses of sildenafil on mortality in adults with PAH was conducted following the observation of a higher risk of mortality in pediatric patients taking a high dose of Sildenafil citrate TID, based on body weight, compared to those taking a lower dose of Sildenafil citrate in the long-term extension of the pediatric clinical trial. The study was a randomized, double-blind, parallel-group study in 385 adults with PAH. Patients were randomly assigned 1:1:1 to one of three treatment groups (5, 20, and 80 mg TID).

12.2 Pharmacodynamics

The estimated difference between the sildenafil medium dose group and placebo was 11±5% (95% CI: 2 to 21). Impact on Hemodynamic Parameters Dose related improvements were observed with PVRI and mPAP. Statistically significant PVRI reductions compared to placebo were seen with the sildenafil medium and high dose groups (18% [95% CI: -32% to -2%] and sildenafil 20 mg tablets 27% [95% CI: -39% to -14%], respectively) but not the low dose group (2% (95% CI: -20%, 20%). The sildenafil medium and high dose groups displayed mPAP changes from baseline compared to placebo, of -3.5 mmHg (95% CI: -8.9, 1.9) and -7.3 mmHg (95% CI: -12.4, -2.1), respectively; while the low dose group showed little difference from placebo (difference of 1.6 mmHg [95% CI: -4.5, 7.6]). Improvements were observed with cardiac index with all three sildenafil groups over placebo, 10%, 4%, and 15% for the low, medium, and high dose groups, respectively [see Clinical Pharmacology (12.2)].

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STARTS-2 (NCT00159874) - Long-Term Survival with Oral Sildenafil Monotherapy in Treatment-Naïve Pediatric Pulmonary Arterial Hypertension Of the 234 pediatric patients treated in the short-term, placebo-controlled study, 220 patients entered the long-term extension study. Patients who had been in the placebo group in the short-term study were randomly reassigned to sildenafil treatment; patients weighing ≤20 kg entered the medium or high dose groups (1:2), while patients weighing >20 kg entered the low, medium, or high dose groups (1:1:1). Of the total 229 patients who received sildenafil, there were 55, 74, and 100 patients in the low, medium, and high dose groups, respectively. Across the short-term and long-term studies, the overall duration of treatment from start of double-blind for individual patients ranged from 3 to 3,129 days. By sildenafil treatment group, median duration of sildenafil treatment was 1,696 days (excluding the 5 patients who received placebo in double-blind and were not treated in the long-term extension study).

5.2 Worsening Pulmonary Vascular Occlusive Disease

Peak VO2 was assessed 1 year after the start of the placebo-controlled study. Of sildenafil-treated patients developmentally able to perform the CPET 59/114 patients (52%) had not shown any deterioration in PVO2 from start of sildenafil. Similarly, 191 of 229 patients (83%) who had received sildenafil had either maintained or improved their WHO Functional Class at 1 year assessment. Kaplan-Meier estimates of survival at 3 years in patients >20 kg in weight at baseline were 94%, 93%, and 85% in the low, medium, and high dose groups, respectively; for patients ≤20 kg in weight at baseline, the survival estimates were 94% and 93% for patients in the medium and high dose groups, respectively [see Use in Specific Populations (8.4) and Adverse Reactions (6.1)]. Study A1481324 (NCT02060487) - Study to Assess the Effects of Sildenafil citrate on Mortality in Adults with PAH A study to assess the effects of multiple doses of sildenafil on mortality in adults with PAH was conducted following the observation of a higher risk of mortality in pediatric patients taking a high dose of Sildenafil citrate TID, based on body weight, compared to those taking a lower dose of Sildenafil citrate in the long-term extension of the pediatric clinical trial. Most patients were PAH treatment naïve (83%). For most patients the etiology of PAH was idiopathic (72%).

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The most common WHO Functional Class was Class III (58% of patients).

• Sildenafil tablets 125 mg are manufactured by various brands.
• Always verify the authenticity of medication sources.
• Use only FDA-approved or certified pharmacies.
• Cost can vary based on brand and location.
• Generic versions are typically more affordable.
• Beware of counterfeit sildenafil products.
• Read customer reviews before purchasing online.
• Consult your doctor about the best brand for you.

Treatment groups were well balanced with respect to baseline demographics of strata history of PAH treatment and etiology of PAH, as well as the WHO Functional Class categories. The primary objective of the study was to compare sildenafil 80 mg TID versus 5 mg TID for mortality, with success defined by ruling out twice the mortality at 80 mg.

2.4 Dosage Adjustments Due to Drug Interactions

The same was seen at Month 12, the median change from baseline for sildenafil 80 mg TID group was 33 m compared to 17 m for sildenafil 5 mg TID and 31 m in sildenafil 20 mg TID groups. Overall, the safety data for sildenafil 20 mg TID and for the higher sildenafil 80 mg TID dose were consistent with the established safety profile of sildenafil in previous adult PAH studies [see Adverse Reactions (6.1)]. Sildenafil 20 mg tablets USP are white to off-white, round biconvex film coated tablets debossed with '85' on one side and plain on other side. Bottles of 30 Tablets NDC: 80425-0304-01 Bottles of 60 Tablets NDC: 80425-0304-02 Bottles of 90 Tablets NDC: 80425-0304-03 Bottles of 50 Tablets NDC: 80425-0304-04 Recommended Storage for Sildenafil Tablets USP: Store at 20°C to 25°C (68°F to 77°F); excursions permitted between 15°C and 30°C (59°F and 86°F) [see USP Controlled Room Temperature]. Advise the patient to read the FDA-approved patient labeling (Patient Information).

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• Inform patients of contraindication of sildenafil tablets with regular and/or intermittent use of organic nitrates. • Inform patients that sildenafil is also marketed as VIAGRA for erectile dysfunction. Advise patients taking sildenafil tablets not to take VIAGRA or other PDE-5 inhibitors. • Advise patients to seek immediate medical attention for a sudden loss of vision in one or both eyes while taking sildenafil tablets. • Advise patients to seek prompt medical attention in the event of sudden decrease or loss of hearing while taking sildenafil tablets.

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Trademarks are the property of their respective owners. Package insert / product label Generic name: sildenafil citrate Dosage form: powder, for oral suspension Drug classes: Agents for pulmonary hypertension, Impotence medications Adults Sildenafil is a phosphodiesterase-5 (PDE-5) inhibitor indicated for the treatment of pulmonary arterial hypertension (PAH) (World Health Organization [WHO] Group I) in adults to improve exercise ability and delay clinical worsening. Pediatric Patients (1 to 17 years old) Sildenafil for oral suspension is indicated in pediatric patients 1 to 17 years old for the treatment of pulmonary arterial hypertension (PAH) (WHO Group I) to improve exercise ability and, in pediatric patients too young to perform standard exercise testing, pulmonary hemodynamics thought to underlie improvements in exercise (1, 14) Adults: 20 mg orally three times a day. The key secondary efficacy endpoint was time to first event of clinical worsening, defined as a composite endpoint of all-cause mortality, hospitalization for worsening PAH or disease progression. An additional secondary endpoint was 6MWD at Months 6 and 12.

4.3 Concomitant Guanylate Cyclase (GC) Stimulators

Overall Survival At the time of a planned interim analysis (50% deaths) it was identified that the primary efficacy objective of this protocol was met and therefore the study sildenafil for women was stopped.

Based on the primary efficacy endpoint (mortality), the non-inferiority of sildenafil 80 mg TID arm versus 5 mg TID arm was met using a 2-sided significance level of 0.003 for the interim analysis. Primary comparison of the 80 mg TID group to the 5-mg TID group yielded the HR (99.7% CI) = 0.51 (0.22, 1.21); i.e., non-inferiority was established. Kaplan-Meier estimates of survival at 3 years were 66%, 79%, and 85% in the 5-, 20-, and 80mg TID dose groups, respectively Clinical Worsening Sildenafil 80 mg was also superior to 5 mg for time to first event of clinical worsening with HR (99.7% CI) = 0.44 (0.22, 0.89). At baseline, the median of 6MWD for the intent-to-treat (ITT) population was 332 to 352 m. At Month 6, the median change from baseline was highest for sildenafil 80 mg TID with 28 m compared to 18 m and 19 m for sildenafil 5 mg TID and sildenafil 20 mg TID groups, respectively. The same was seen at Month 12, the median change from baseline for sildenafil 80 mg TID group was 33 m compared to 17 m for sildenafil 5 mg TID and 31 m in sildenafil 20 mg TID groups. Overall, the safety data for sildenafil 20 mg TID and for the higher sildenafil 80 mg TID dose were consistent with the established safety profile of sildenafil in previous adult PAH studies [see Adverse Reactions (6.1)]. Sildenafil 20 mg tablets USP are white to off-white, round biconvex film coated tablets debossed with '85' on one side and plain on other side. Bottles of 30 Tablets NDC: 80425-0304-01 Bottles of 60 Tablets NDC: 80425-0304-02 Bottles of 90 Tablets NDC: 80425-0304-03 Bottles of 50 Tablets NDC: 80425-0304-04 Recommended Storage for Sildenafil Tablets USP: Store at 20°C to 25°C (68°F to 77°F); excursions permitted between 15°C and 30°C (59°F and 86°F) [see USP Controlled Room Temperature]. Advise the patient to read the FDA-approved patient labeling (Patient Information). • Inform patients of contraindication of sildenafil tablets with regular and/or intermittent use of organic nitrates. • Inform patients that sildenafil is also marketed as VIAGRA for erectile dysfunction. Advise patients taking sildenafil tablets not to take VIAGRA or other PDE-5 inhibitors. • Advise patients to seek immediate medical attention for a sudden loss of vision in one or both eyes while taking sildenafil tablets. • Advise patients to seek prompt medical attention in the event of sudden decrease or loss of hearing while taking sildenafil tablets. Trademarks are the property of their respective owners. Package insert / product label Generic name: sildenafil citrate Dosage form: powder, for oral suspension Drug classes: Agents for pulmonary hypertension, Impotence medications Adults Sildenafil is a phosphodiesterase-5 (PDE-5) inhibitor indicated for the treatment of pulmonary arterial hypertension (PAH) (World Health Organization [WHO] Group I) in adults to improve exercise ability and delay clinical worsening.

• Sildenafil is sometimes used off-label for other health issues.
• Its interaction with blood thinners should be monitored.
• Men with retinitis pigmentosa should avoid sildenafil.
• Always inform healthcare providers about all treatments.
• Use sildenafil in conjunction with a healthy lifestyle.
• Avoid unnecessary medication to prevent side effects.
• Be aware of potential drug interactions with sildenafil.
• Proper storage maintains medication efficacy over time.

Pediatric Patients (1 to 17 years old) Sildenafil for oral suspension is indicated in pediatric patients 1 to 17 years old for the treatment of pulmonary arterial hypertension (PAH) (WHO Group I) to improve exercise ability and, in pediatric patients too young to perform standard exercise testing, pulmonary hemodynamics thought to underlie improvements in exercise (1, 14) Adults: 20 mg orally three times a day.

8.2 Lactation