Clinical Pharmacology for Clenpiq
Mechanism Of Action
Sodium picosulfate is hydrolyzed by colonic bacteria to form an active metabolite: bis-(p-hydroxy-phenyl)-pyridyl-2-methane, BHPM, which acts directly on the colonic mucosa to stimulate colonic peristalsis. Magnesium oxide and citric acid react to create magnesium citrate in solution, which is an osmotic agent that causes water to be retained within the gastrointestinal tract.
Pharmacodynamics
The stimulant laxative activity of sodium picosulfate together with the osmotic laxative activity of magnesium citrate produces a purgative effect which, when ingested with additional liquids, produces watery diarrhea.
Pharmacokinetics
Absorption
After administration of the first dose of another oral sodium picosulfate, magnesium oxide, and anhydrous citric acid product in 16 healthy subjects, the mean ± SD maximum plasma concentration (Cmax) for picosulfate of 2.3 ± 1.4 ng/mL was reached at 2 hours.
After administration of two doses separated by 6 hours, the mean ± SD plasma Cmax for picosulfate of 3.2 ± 2.6 ng/mL was reached at approximately 7 hours after the first dose administration. In the same study, the uncorrected plasma magnesium concentration reached a Cmax of approximately 1.9 mEq/L at 10 hours after the first dose administration, which represents an approximately 20% increase from baseline.
In patients scheduled to have an elective colonoscopy who received the Split-Dose dosage regimen of CLENPIQ, the mean ± SD plasma concentration for picosulfate was 1.05 ± 0.83 ng/mL at 15 minutes pre-second dose, 2.98 ± 1.27 ng/mL at 1-2 hours post-second dose, and 1.81 ± 0.86 ng/mL at 3-6 hours post-second dose.
Metabolism And Elimination
Metabolism And Excretion
Plasma concentrations of the free BHPM were below the lower limit of quantification (0.1 ng/mL) in 13 out of 16 subjects studied. The fraction of the sodium picosulfate dose excreted unchanged in urine was 0.1%. In urine, the majority of excreted BHPM was in the glucuronide-conjugated form. The terminal half-life of sodium picosulfate was 7.4 hours.
Use In Specific Populations
Pediatric Patients
Pharmacokinetics of picosulfate was studied in pediatric patients aged from 9 to 16 years old. The half-life of picosulfate was 7 hours. The picosulfate reached the mean ± SD Cmax of 3.5 ± 2.1 ng/mL at approximately 6 to 7 hours. The baseline uncorrected mean serum magnesium concentration was 2.02 mEq/L at 10 hours after the first dose of sodium picosulfate, magnesium oxide, and anhydrous citric acid and ranged from 1.7 to 2.46 mEq/L.
Drug Interaction Studies
In an in vitro study using human liver microsomes, sodium picosulfate did not inhibit the major CYP enzymes (CYP 1A2, 2B6, 2C8, 2C9, 2C19, 2D6, and 3A4/5) evaluated. Based on an in vitro study using freshly isolated hepatocyte culture, sodium picosulfate is not an inducer of CYP1A2, CYP2B6, or CYP3A4/5.
Clinical Studies
Adults
Clinical Study With CLENPIQ – Study 1
The colon-cleansing efficacy of CLENPIQ was evaluated in a randomized, investigator-blinded, active-controlled, multicenter non-inferiority trial in the US and Canada in adult patients scheduled to have an elective colonoscopy (NCT03017235). Patients were randomized to CLENPIQ or another oral sodium picosulfate, magnesium oxide, and anhydrous citric acid product. Both products were administered by the “Split-Dose” (evening before and day of) dosing, where the first dose was taken the evening before the colonoscopy (between 5:00 and 9:00 PM), followed by at least five (5) 8-ounce glasses of clear liquid, and the second dose was taken the morning of the colonoscopy (at least 5 hours prior to but no more than 9 hours prior to colonoscopy), followed by at least four (4) 8-ounce glasses of clear liquid. Patients in both treatment groups were limited to a clear liquid diet on the day before the procedure (24 hours before).
A total of 901 adult patients were included in the primary efficacy analysis. Patients ranged in age from 20 to 80 years (mean age 57 years); 56% were female and 44% male. Self-identified race was approximately distributed as follows: 85% White, 10% Black, 2% Asian, and 3% other. Approximately 15% of patients self-identified their ethnicity as Hispanic or Latino.
The primary efficacy endpoint was the proportion of patients with successful overall colon cleansing, as assessed by blinded colonoscopists using the Modified Aronchick Scale. The Modified Aronchick Scale is a validated tool used to assess overall colon cleansing prior to suctioning or cleaning. Successful colon cleansing was defined as bowel preparations with >90% of the mucosa seen and mostly liquid stool that were graded excellent (minimal suctioning needed for adequate visualization) or good (significant suctioning needed for adequate visualization) by the colonoscopist.
In the trial, CLENPIQ was non-inferior and also met the pre-specified criteria for superiority to the comparator for overall colon cleansing. Efficacy results are provided in Table 4.
Table 4: Proportion of Patients with Successful Colon Cleansing According to the Modified Aronchick Scale in Study 1 Using the Split-Dose Regimen
| CLENPIQ % (n/N) |
Sodium picosulfate, magnesium oxide, and anhydrous citric acid1% (n/N) |
Difference between treatment groups2 |
| Difference |
95% CI |
| 87.7% (393/448) |
81.5% (369/453) |
6.3% |
(1.8%, 10.9%)3 |
1 Powder for reconstitution
2 Difference and 95% CI are based on stratified difference in proportions, where the stratification weight is based on Cochran-Mantel-Haenszel weight.
3 Non-inferior and superior to sodium picosulfate, magnesium oxide, and anhydrous citric acid |
Clinical Study Of Another Oral Sodium Picosulfate, Magnesium Oxide And Anhydrous Citric Acid Product – Study 2
The colon cleansing efficacy of another oral sodium picosulfate, magnesium oxide, and anhydrous citric acid product was evaluated in a randomized, investigator-blinded, active-controlled, multicenter US non-inferiority trial in adult patients scheduled to have an elective colonoscopy (NCT01073930).
Patients were randomized to sodium picosulfate, magnesium oxide, and anhydrous citric acid group or polyethylene glycol plus electrolytes (PEG + E) and bisacodyl.
- Sodium picosulfate, magnesium oxide, and anhydrous citric acid was given by “Split-Dose” (evening before and day of) dosing, where the first dose was taken the evening before the colonoscopy (between 5:00 and 9:00 PM), followed by five (5) 8-ounce glasses of clear liquid, and the second dose was taken the morning of the colonoscopy (at least 5 hours prior to but no more than 9 hours prior to colonoscopy), followed by three (3) 8-ounce glasses of clear liquid.
- The comparator was given as two liters of polyethylene glycol plus electrolytes solution (PEG + E) and two 5-mg bisacodyl tablets, administered the day before the procedure.
All patients in both treatment groups were limited to a clear liquid diet on the day before the procedure (24 hours before).
A total of 601 adult patients were included in the primary efficacy analysis. Patients ranged in age from 18 to 80 years (mean age 55 years); 59% were female and 41% male. Self-identified race was distributed as follows: 88% White, 10% Black, and less than 2% other. Of these, 2% self-identified their ethnicity as Hispanic or Latino.
The primary efficacy endpoint was the proportion of patients with successful colon cleansing, as assessed by blinded colonoscopists using the Aronchick Scale. The Aronchick scale is a tool used to assess overall colon cleansing. Successful colon cleansing was defined as bowel preparations with >90% of the mucosa seen and mostly liquid stool that were graded excellent (minimal suctioning needed for adequate visualization) or good (significant suctioning needed for adequate visualization) by the colonoscopist.
Sodium picosulfate, magnesium oxide, and anhydrous citric acid was non-inferior to the comparator. In addition, sodium picosulfate, magnesium oxide, and anhydrous citric acid met the pre-specified criteria for superiority to the comparator for colon cleansing. Efficacy results are provided in Table 5.
Table 5: Proportion of Patients with Successful Colon Cleansing in Study 2
| Sodium picosulfate, magnesium oxide, and anhydrous citric acid % (n/N) |
2 L PEG+E1 with 2 x 5-mg bisacodyl tablets % (n/N) |
Difference between treatment groups |
| Difference |
95% CI |
| 84% (256/304) |
74% (221/297) |
10% |
(3.4%, 16.2%)2 |
1 2 L PEG + E = two liters polyethylene glycol plus electrolytes solution.
2 Non-inferior and superior to 2 L PEG+E with 2 x 5-mg bisacodyl tablets |
Pediatric Patients 9 Years Of Age And Older
The safety and efficacy of CLENPIQ in pediatric patients 9 years of age and older has been established based on another oral product of sodium picosulfate, magnesium oxide and anhydrous citric acid provided in powder packets for reconstitution (NCT01928862).
Sodium picosulfate, magnesium oxide, and anhydrous citric acid was evaluated for colon cleansing in a randomized, assessor-blind, multicenter, dose-ranging, active-controlled study in 78 pediatric patients 9 years to 16 years of age. The majority of patients were female (68%), white (91%), and of non-Hispanic or non-Latino ethnicity (95%). The mean age was 12 years of age. All 78 patients were included in the primary efficacy analysis.
Patients aged 9 years to 12 years were randomized into 3 arms (1:1:1):
- Sodium picosulfate, magnesium oxide, and anhydrous citric acid one-half packet per dose administered as two doses
- Sodium picosulfate, magnesium oxide, and anhydrous citric acid one packet per dose administered as two doses
- Comparator (oral PEG-based solution per local standard of care).
Patients aged 13 years to 16 years were randomized into 2 arms (1:1):
- Sodium picosulfate, magnesium oxide, and anhydrous citric acid one packet per dose administered as two doses
- Comparator (oral PEG-based solution per local standard of care)
Patients randomized to sodium picosulfate, magnesium oxide, and anhydrous citric acid had two options for dosing, as determined by the investigator. The “Split-Dose” regimen was the preferred method and the “Day-Before” regimen was the alternative method if the “Split-Dose” was not appropriate.
“Split-Dose” Regimen: (evening before and day of) dosing, where the first dose was taken the evening before the colonoscopy (between 5:00 and 9:00 PM), followed by five (5) 8-ounce glasses of clear liquid, and the second dose was taken the morning of the colonoscopy (at least 5 hours prior to but no more than 9 hours prior to colonoscopy), followed by three (3) 8-ounce glasses of clear liquid.
“Day-Before” Regimen: (afternoon/evening before only) dosing, where both doses were taken separately on the day before the colonoscopy, with the first dose taken in the afternoon (between 4:00 and 6:00 PM), followed by five (5) 8-ounce glasses of clear liquid, and the second dose taken in the late evening (approximately 6 hours later, between 10:00 PM and 12:00 AM), followed by three (3) 8-ounce glasses of clear liquid.
All patients randomized to sodium picosulfate, magnesium oxide, and anhydrous citric acid was limited to a clear liquid diet on the day before the procedure. Those who received the comparator were given dietary instructions per the trial site’s standard of care.
The primary efficacy endpoint was the proportion of patients with successful colon cleansing as defined as a rating of either “Excellent” (> 90% of mucosa seen, mostly liquid stool, minimal suctioning needed for adequate visualization) or “Good” (> 90% of mucosa seen, mostly liquid stool, significant suctioning needed for adequate visualization) using the Aronchick scale, as assessed by blinded colonoscopists.
The sodium picosulfate, magnesium oxide, and anhydrous citric acid regimen of one-half packet per dose administered as two doses did not demonstrate comparable efficacy to the comparator, PEG, in patients 9 to 12 years of age and is not a CLENPIQ recommended dosage regimen [see DOSAGE AND ADMINISTRATION].
The sodium picosulfate, magnesium oxide, and anhydrous citric acid regimen of one packet per dose administered as two doses demonstrated successful colon cleansing in both the 9 to 12 year age group and the 13 to 16 year age group. The efficacy rates were similar to those observed in the PEG groups, as shown in Table 6.
Table 6: Proportion of Patients 9 to 16 Years of Age with Successful Colon Cleansing1
|
Sodium Picosulfate, Magnesium Oxide, and Anhydrous Citric Acid, One Packet Administered as Two Doses either as Split Dose or Day Before Regimen2 |
PEG Comparator3 |
| % (n/N) |
95% CI |
% (n/N) |
95% CI |
| Age 9-12 |
88% (14/16) |
(62, 98) |
81% (13/16) |
(54, 96) |
| Age 13-16 |
81% (13/16) |
(54, 96) |
86% (12/14) |
(57, 98) |
1 Successful colon cleansing as defined by “Excellent” or “Good” on the Aronchick scale
2 Of the 32 patients, 9 received the Split Dose Regimen and 23 the Day Before Regimen
3 Oral PEG-based preparation was used in the study as per standard of care |