Clinical Pharmacology for Gemtesa
Mechanism Of Action
Vibegron is a selective human beta-3 adrenergic receptor agonist. Activation of the beta-3 adrenergic receptor increases bladder capacity by relaxing the detrusor smooth muscle during bladder filling.
Pharmacodynamics
Vibegron’s exposure-response relationship and the time course of pharmacodynamic response are not fully characterized.
Blood Pressure
In a 4-week, randomized, placebo-controlled, ambulatory blood pressure study in OAB patients (n=200), daily treatment with GEMTESA 75 mg was not associated with clinically significant changes in blood pressure. Subjects enrolled in this study had a mean age of 59 years and 75% were female. Thirty-five percent of subjects had pre-existing hypertension at baseline and 29% of all subjects were taking at least 1 concomitant antihypertensive medication.
Cardiac Electrophysiology
GEMTESA does not prolong the QT interval to any clinically relevant extent at a single dose 5.3 times the approved recommended dose.
Pharmacokinetics
Mean vibegron Cmax and AUC increased in a greater than dose-proportional manner up to 600 mg (8 times the approved recommended dosage). Steady state concentrations are achieved within 7 days of once daily dosing. The mean accumulation ratio (Rac) was 1.7 for Cmax and 2.4 for AUC0-24hr.
Absorption
Median vibegron Tmax is approximately 1 to 3 hours.
Oral administration of a 75 mg vibegron tablet crushed and mixed with 15 mL of applesauce resulted in no clinically relevant changes in vibegron pharmacokinetics when compared to administration of an intact 75 mg vibegron tablet.
Effect of Food
No clinically significant differences in vibegron pharmacokinetics were observed following administration of a high-fat meal (53% fat, 869 calories [32.1 g protein, 70.2 g carbohydrate, and 51.1 g fat]).
Distribution
The mean apparent volume of distribution is 6304 liters. Human plasma protein binding of vibegron is approximately 50%. The average blood-to-plasma concentration ratio is 0.9.
Elimination
Vibegron has an effective half-life of 30.8 hours across all populations.
Metabolism
Metabolism plays a minor role in the elimination of vibegron. CYP3A4 is the predominant enzyme responsible for in vitro metabolism.
Excretion
Following a radiolabeled dose, approximately 59% of the dose (54% as unchanged) was recovered in feces and 20% (19% as unchanged) in urine.
Specific Populations
No clinically significant differences in the pharmacokinetics of vibegron were observed based on age (18 to 93 years), sex, race/ethnicity (Japanese vs. non-Japanese), mild (eGFR 60 to <90 mL/min/1.73 m2), moderate (eGFR 30 to <60 mL/min/1.73 m2), and severe (eGFR 15 to <30 mL/min/1.73 m2) renal impairment, or moderate (Child-Pugh B) hepatic impairment. The effect of more severe renal impairment (eGFR <15 mL/min/1.73 m2) with or without hemodialysis or severe (Child-Pugh C) hepatic impairment on vibegron pharmacokinetics was not studied.
Drug Interaction Studies
Clinical Studies
Digoxin
Concomitant administration of vibegron increased digoxin Cmax and AUC by 21% and 11%, respectively.
Other Drugs
No clinically significant differences in vibegron pharmacokinetics were observed when used concomitantly with ketoconazole (P-gp and strong CYP3A4 inhibitor), diltiazem (P-gp and moderate CYP3A4 inhibitor), rifampin (strong CYP3A4 inducer), or tolterodine. No clinically significant differences in the pharmacokinetics of the following drugs were observed when used concomitantly with vibegron: tolterodine, tolterodine 5-hydroxy metabolite, metoprolol, combined oral contraceptive (ethinyl estradiol, levonorgestrel), or warfarin.
In Vitro Studies
Cytochrome P450 (CYP) Enzymes
Vibegron is a CYP3A4 substrate. Vibegron did not inhibit CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, or CYP3A4. Vibegron did not induce CYP1A2, CYP2B6, or CYP3A4.
Transporter Systems
Vibegron is a P-gp substrate. Vibegron did not inhibit P-gp, BCRP, OATP1B1, OATP1B3, OAT1, OAT3, OCT1, OCT2, MATE1, or MATE2K at clinically relevant concentrations.
Clinical Studies
Overactive Bladder In Adults
The efficacy of GEMTESA was evaluated in a 12-week, double-blind, randomized, placebo-controlled, and active-controlled trial (Study 3003, NCT03492281) in patients with OAB (urge urinary incontinence, urgency, and urinary frequency). Patients were randomized 5:5:4 to receive either GEMTESA 75 mg, placebo, or active control orally, once daily for 12 weeks. For study entry, patients had to have symptoms of OAB for at least 3 months with an average of 8 or more micturitions per day and at least 1 urge urinary incontinence (UUI) per day, or an average of 8 or more micturitions per day and an average of at least 3 urgency episodes per day. Urge urinary incontinence was defined as leakage of urine of any amount because the patient felt an urge or need to urinate immediately. The study population included OAB medication-naïve patients as well as patients who had received prior therapy with OAB medications.
The co-primary endpoints were change from baseline in average daily number of micturitions and average daily number of UUI episodes at week 12. Additional endpoints included change from baseline in average daily number of “need to urinate immediately” (urgency) episodes and average volume voided per micturition.
A total of 1,515 patients received at least one daily dose of placebo (n=540), GEMTESA 75 mg (n=545), or an active control treatment (n=430). The majority of patients were White (78%) and female (85%) with a mean age of 60 (range 18 to 93) years.
Table 3 shows changes from baseline at week 12 for average daily number of micturitions, average daily number of UUI episodes, average daily number of “need to urinate immediately” (urgency) episodes, and average volume voided per micturition.
Table 3: Mean Baseline and Change from Baseline at Week 12 for Micturition Frequency, Urge Urinary Incontinence Episodes, "Need to Urinate Immediately" (Urgency) Episodes, and Volume Voided per Micturition
| Parameter |
GEMTESA
75 mg |
Placebo |
| Average Daily Number of Micturitions |
| Baseline mean (n) |
11.3 (526) |
11.8 (520) |
| Change from Baseline* (n) |
-1.8 (492) |
-1.3 (475) |
| Difference from Placebo |
-0.5 |
| 95% Confidence Interval |
-0.8, -0.2 |
| p-value |
<0.001 |
| Average Daily Number of UUI Episodes |
| Baseline mean (n) |
3.4 (403) |
3.5 (405) |
| Change from Baseline* (n) |
-2.0 (383) |
-1.4 (372) |
| Difference from Placebo |
-0.6 |
| 95% Confidence Interval |
-0.9, -0.3 |
| p-value |
<0.0001 |
| Average Daily Number of “Need to Urinate Immediately” (Urgency) Episodes |
| Baseline mean (n) |
8.1 (526) |
8.1 (520) |
| Change from Baseline* (n) |
-2.7 (492) |
-2.0 (475) |
| Difference from Placebo |
-0.7 |
| 95% Confidence Interval |
-1.1, -0.2 |
| p-value |
0.002 |
| Average Volume Voided (mL) per Micturition |
| Baseline mean (n) |
155 (524) |
148 (514) |
| Change from Baseline* (n) |
23 (490) |
2 (478) |
| Difference from Placebo |
21 |
| 95% Confidence Interval |
14, 28 |
| p-value |
<0.0001 |
| * Least squares mean adjusted for treatment, baseline, sex, geographical region, study visit,and study visit by treatment interaction term |
Figure 1 and Figure 2 show the mean change from baseline over time in average daily number of micturitions and mean change from baseline over time in average daily number of UUI episodes, respectively.
Figure 1: Mean (SE) Change from Baseline in the Average Daily Number of Micturitions
Figure 2: Mean (SE) Change from Baseline in the Average Daily Number of UUI Episodes in Patients with At Least 1 Average Daily UUI Episode at Baseline
Overactive Bladder In Adult Males With BPH
The safety, tolerability, and efficacy of GEMTESA was evaluated in a multinational 24-week, double-blind, randomized, placebo-controlled trial (Study 3005, NCT03902080) in male patients at least 45 years of age with OAB on pharmacological therapy (i.e., treatment with an alpha blocker, with or without a 5-alpha reductase inhibitor) for BPH. A total of 1105 patients were randomized 1:1 to receive either GEMTESA 75 mg or placebo once daily for 24 weeks. For study entry, patients had symptoms of OAB (an average of 8 or more micturitions per day, 3 or more urgency episodes per day with or without incontinence, and 2 or more nocturia episodes per night) while taking pharmacological therapy for at least 2 months for the treatment of lower urinary tract symptoms due to BPH. Randomization was stratified based on the baseline average number of micturition episodes per day, alpha blocker use with or without 5 alpha reductase inhibitor use, and urinary incontinence.
The co-primary endpoints were change from baseline in the average daily number of micturitions and the average daily number of “need to urinate immediately” (urgency) episodes at week 12. Additional endpoints included change from baseline in the average daily number of urge urinary incontinence (UUI) episodes and the average volume voided per micturition.
A total of 1104 patients received at least one daily dose of placebo (n=551) or GEMTESA 75 mg (n=553). The majority of patients were White (87%) and enrolled in the U.S. (56%). The mean age was 67 years (range 45 to 97) and at least 63% were ≥ 65 years.
Table 4 shows changes from baseline at week 12 for average daily number of micturitions, average daily number of urgency episodes, average daily number of UUI episodes and average volume voided per micturition.
Table 4: Mean Baseline and Change from Baseline at Week 12 for Micturition Frequency, "Need to Urinate Immediately" (Urgency Episodes), UUI Episodes and Volume Voided per Micturition
| Parameter |
GEMTESA 75 mg
(N = 538) |
Placebo
(N = 542) |
| Average Daily Number of Micturitions |
| Baseline mean |
11.84 |
11.96 |
| Change from Baseline* |
-2.04 |
-1.30 |
| Difference from Placebo |
-0.74 |
| 95% Confidence Interval |
-1.02, -0.46 |
| Average Daily Number of “Need to Urinate Immediately” (Urgency) Episodes |
| Baseline mean |
9.05 |
9.00 |
| Change from Baseline* |
-2.88 |
-1.93 |
| Difference from Placebo |
-0.95 |
| 95% Confidence Interval |
-1.37, -0.54 |
| Average Daily Number of UUI Episodes |
| N *** |
146 |
151 |
| Baseline mean |
3.33 |
3.23 |
| Change from Baseline* |
-2.19 |
-1.39 |
| Difference from Placebo |
-0.80 |
| 95% Confidence Interval |
-1.33, -0.27 |
| Average Volume Voided (mL) per Micturition |
| Baseline mean |
166.37 |
166.43 |
| Change from Baseline* |
25.63 |
10.56 |
| Difference from Placebo |
15.07 |
| 95% Confidence Interval |
9.13, 21.02 |
* Least squares mean adjusted for study visit, baseline value, geographical region, interaction of visit by treatment, and stratification factors as randomized (baseline average micturitions per day**, alpha blocker use with or without 5-ARI, baseline urinary incontinence**), geographical region, study visit, and study visit by treatment interaction term.
** Baseline average micturitions per day stratification factor is not included in the model where the continuous value of baseline average micturitions per day is present; baseline urinary incontinence is not included in the model for UUI;
*** Only subjects with baseline incontinence have UUI analyzed. |
Figure 3 and Figure 4 show the mean change from baseline over time in average daily number of micturitions and mean change from baseline over time in average daily number of urgency episodes, respectively.
Figure 3: Mean (SE) Change from Baseline in the Average Daily Number of Micturitions in Male Patients with BPH on Pharmacological Therapy
Figure 4: Mean (SE) Change from Baseline in the Average Daily Number of Urgency Episodes in Male Patients with BPH on Pharmacological Therapy