Clinical Pharmacology for Livdelzi
Mechanism Of Action
Seladelpar is a peroxisome proliferator-activated receptor (PPAR)-delta (δ) agonist. However, the mechanism by which seladelpar exerts its therapeutic effects in patients with PBC is not well understood. Pharmacological activity that is potentially relevant to therapeutic effects includes inhibition of bile acid synthesis through activation of PPARδ, which is a nuclear receptor expressed in most tissues, including the liver. Published studies show that PPARδ activation by seladelpar reduces bile acid synthesis through Fibroblast Growth Factor 21 (FGF21)-dependent downregulation of CYP7A1, the key enzyme for the synthesis of bile acids from cholesterol.
Pharmacodynamics
Pharmacodynamic Markers
In patients with PBC treated with 10 mg once daily of LIVDELZI (Trial 1), a greater reduction in mean ALP from baseline was observed as early as 1 month after treatment compared to the placebo group and lower ALP was generally maintained through month 12 [see Clinical Studies].
In another study in which patients with PBC were treated with 2, 5, or 10 mg once daily of seladelpar, a dose dependent reduction in mean ALP was observed.
Cardiac Electrophysiology
At 20-times the recommended dose of 10 mg, LIVDELZI did not cause clinically significant QTc interval prolongation.
Pharmacokinetics
Following a single dose administration, seladelpar systemic exposure increased dose-proportionally from 2 mg (0.2 times the recommended dosage) to 15 mg (1.5 times the recommended dosage) and greater than dose proportionally at higher doses. For a dose increase from 10 mg to 200 mg (20 times the recommended dosage), mean Cmax and mean AUC for seladelpar increased 70-fold and 27-fold, respectively.
Following once daily dosing, seladelpar steady-state was achieved by day 4 and AUC increase was less than 30%. In PBC patients, mean (SD) Cmax and AUC for seladelpar was 103 (29.3) ng/mL and 902 (238) ng*h/mL, respectively at steady state following once daily dosing of 10 mg.
Absorption
The median time to peak concentration (Tmax) was 1.5 hours for seladelpar.
Effect of Food
No clinically significant differences in seladelpar pharmacokinetics were observed following administration of a high-fat meal in healthy subjects.
Distribution
Seladelpar steady state apparent volume of distribution was approximately 133.2 L. Seladelpar plasma protein binding is greater than 99%.
Elimination
The apparent oral clearance of seladelpar is 12 L/h. Following administration of a single dose of 10 mg seladelpar in healthy subjects, mean elimination half-life was 6 hours for seladelpar. In PBC patients, the half-life range was 3.8 to 6.7 hours for seladelpar.
Metabolism
Seladelpar is primarily metabolized in vitro by CYP2C9 and to a lesser extent by CYP2C8 and CYP3A4, resulting in the three major metabolites: seladelpar sulfoxide (M1), desethyl-seladelpar (M2), and desethyl-seladelpar sulfoxide (M3). The metabolite-to-parent AUC ratios were 0.36, 2.32 and 0.63 for M1, M2 and M3, respectively. Median Tmax for metabolites were 10 hours for M1 and 4 hours for M2 and M3. None of the major metabolites have pharmacological activity.
Excretion
Seladelpar is primarily eliminated in urine as metabolites. Following a single oral dose of 10 mg radiolabeled seladelpar in humans, approximately 73.4% of the dose was recovered in urine (less than 0.01% unchanged) and 19.5% in feces (2.02% unchanged) within 216 hours. Biliary excretion of seladelpar was suggested by an animal study.
Specific Populations
No clinically significant differences in the pharmacokinetics of seladelpar were observed based on age (19 to 79 years old), body mass index (BMI) (17.6 to 45.0 kg/m2), weight (45.8 to 127.5 kg), sex, and race (White, Black, or other).
Patients With Renal Impairment
In subjects with mild (eGFR ≥60 to <90 mL/min/1.73 m2, MDRD), moderate (eGFR ≥30 to <60 mL/min/1.73 m2), and severe (<30 mL/min/1.73 m2 and not on dialysis) renal impairment, the AUCinf of seladelpar was 10% higher, 54% higher, and similar to that in subjects with normal renal function, respectively, after administration of a single 10 mg dose of seladelpar. The difference in Cmax of seladelpar was less than 18% in subjects with renal impairment compared to subjects with normal renal function [see Use In Specific Populations]. The pharmacokinetics of seladelpar have not been studied in patients requiring hemodialysis.
Patients With Hepatic Impairment
Hepatic Impairment of various etiologies
Following a single oral dose of 10 mg seladelpar, seladelpar AUC increased 1.1-fold in subjects with mild (Child-Pugh A), 2.5-fold in moderate (Child-Pugh B), and 2.1-fold in severe (Child-Pugh C) hepatic impairment. Seladelpar Cmax increased 1.3-fold in subjects with mild (Child-Pugh A), 5.2-fold in moderate (Child-Pugh B), and 5-fold in severe (Child-Pugh C) hepatic impairment.
Hepatic Impairment in patients with PBC
Compared to PBC patients with mild hepatic impairment (Child-Pugh A) without portal hypertension, seladelpar exposures (Cmax, AUC) were 1.7 to 1.8-fold higher in PBC patients with mild hepatic impairment with portal hypertension and 1.6 to 1.9-fold higher in PBC patients with moderate hepatic impairment (Child-Pugh B) after a single oral dose of 10 mg seladelpar.
Accumulation ratios were less than 1.2-fold in PBC patients with mild hepatic impairment with portal hypertension and PBC patients with moderate hepatic impairment following 10 mg seladelpar once daily dosing for 28 days.
Drug Interaction Studies
Effect Of Other Drugs On Seladelpar
In Vitro Studies
Seladelpar is a substrate of CYP2C9, CYP2C8, CYP3A4, and the transporters BCRP, P-gp, and OAT3.
Seladelpar is not a substrate of MATE1, MATE2-K, OAT1, OATP1B1, OATP1B3, OCT1, or OCT2 transporters.
Carbamazepine
Seladelpar AUC0-inf decreased by approximately 44% and Cmax by 24% following administration of a single 10 mg seladelpar dose after carbamazepine 300 mg twice daily for 8 days in healthy subjects. The carbamazepine (CYP3A and CYP2C9 inducer) dose was escalated from 100 mg twice daily for 3 days followed by 200 mg twice daily for 4 days to 300 mg twice daily.
Fluconazole
Seladelpar AUC0-inf increased by 2.4-fold and Cmax by 1.4-fold following concomitant use of a single 10 mg seladelpar dose with 400 mg fluconazole (moderate CYP2C9 and CYP3A4 inhibitor) in healthy subjects.
Cyclosporine
Seladelpar AUC0-inf increased by 2.1-fold and Cmax by 2.9-fold following concomitant use of a single 10 mg seladelpar dose with 600 mg cyclosporine (BCRP inhibitor) in healthy subjects.
Probenecid
Seladelpar AUC0-inf increased by 2-fold and Cmax by 4.69-fold following concomitant use of a single 10 mg seladelpar dose with 500 mg probenecid (OAT3 inhibitor) in healthy subjects.
Strong CYP2C9 inhibitor
Seladelpar AUC0-inf is predicted to increase by 3.7-fold when coadministered with sulphaphenazole (strong CYP2C9 inhibitor).
Quinidine
Seladelpar exposures were not significantly altered when a single dose of 600 mg quinidine (Pgp inhibitor) was coadministered in healthy subjects.
Other Drugs: No clinically significant differences in seladelpar pharmacokinetics were predicted when used concomitantly with strong CYP3A4 inhibitors or CYP2C8 inhibitors.
Effects Of Seladelpar On Other Drugs
In clinical studies, no clinically significant differences in the pharmacokinetics of the following drugs were observed when used concomitantly with seladelpar: tolbutamide (CYP2C9 substrate), midazolam (CYP3A4 substrate), simvastatin (CYP3A4 and OATP substrate), atorvastatin (CYP3A4 and OATP substrate), or rosuvastatin (BCRP and OATP substrate).
In Vitro Studies
Seladelpar and its metabolites (M1, M2, or M3) did not inhibit CYPs 1A2, 2B6, 2C8, 2C19, 2D6, 3A4. Seladelpar did not induce CYP1A2, CYP2B6, or CYP2C8.
Seladelpar and its metabolites (M1, M2, or M3) did not inhibit UGTs.
Seladelpar and its metabolites (M1, M2, or M3) did not inhibit P-gp, MATE1, MATE2-K, OCT1, OCT2, OAT1, and OAT3.
Pharmacogenomics
CYP2C9 activity is decreased in individuals with genetic variants such as CYP2C9*2 and CYP2C9*3. Compared to CYP2C9 normal metabolizers (*1/*1, n=84) after a single dose of seladelpar 1 mg to 15 mg, dose-normalized AUC0-inf was 48% higher in CYP2C9 poor metabolizers (*2/*3, n=2) and 24% higher in CYP2C9 intermediate metabolizers (*1/*2, *1/*8, *1/*3, *2/*2, n=28). Dose-normalized Cmax was similar for CYP2C9 normal, intermediate, and poor metabolizers. Seladelpar pharmacokinetics was not evaluated in patients who are CYP2C9 poor metabolizers with two no function alleles (e.g., *3/*3). CYP2C9 poor metabolizers may have increased AUC when seladelpar is used concomitantly with a moderate to strong CYP3A4 inhibitor [see DRUG INTERACTIONS, Use In Specific Populations].
The prevalence of CYP2C9 poor metabolizers is approximately 2 to 3% in White populations, 0.5 to 4% in Asian populations, and <1% in African American populations. Additional decreased or nonfunctional alleles (e.g., *5, *6, *11) are more prevalent in African American populations.
Animal Toxicology And/Or Pharmacology
In a 2-year study in CD-1 mice, seladelpar produced an increased incidence of lens cataracts at 5 mg/kg/day in both sexes (6-times and 19-times the recommended dose in male and female mice, respectively, based on AUC). In a 2-year study in Sprague-Dawley rats, seladelpar produced an increased incidence of cornea inflammation at 10 mg/kg/day (14-times the recommended dose based on AUC) and cornea mineralization at 30 mg/kg/day (79-times the recommended dose based on AUC), with both effects observed in males only. The incidence of cornea inflammation was not increased in male rats at 3 mg/kg/day (5-times the recommended dose based on AUC).
Clinical Studies
The efficacy of LIVDELZI was evaluated in Trial 1 (NCT04620733), a 12-month, randomized, double-blind, placebo-controlled trial. The study included 193 adult patients with PBC with an inadequate response or intolerance to UDCA. Patients were included in the trial if their ALP was greater than or equal to 1.67-times the ULN and total bilirubin (TB) was less than or equal to 2times the ULN. Patients were excluded from the trial if they had other chronic liver diseases, clinically important hepatic decompensation including portal hypertension with complications, or cirrhosis with complications (e.g., Model for End Stage Liver Disease [MELD] score of 12 or greater, known esophageal varices or history of variceal bleeds, history of hepatorenal syndrome).
Patients were randomized to receive LIVDELZI 10 mg (N=128) or placebo (N=65) once daily for 12 months. LIVDELZI or placebo was administered in combination with UDCA in 181 (94%) patients during the trial, or as a monotherapy in 12 (6%) patients who were unable to tolerate UDCA.
Baseline Demographics And Characteristics
The mean age of patients was 57 (Range: 28 to 75) years; 95% were female; 88% were White, 6% Asian, 2% Black or African American, and 3% American Indian or Alaska Native. Twenty-nine percent of the patients, 23% in the LIVDELZI 10 mg arm and 42% in the placebo arm, identified as Hispanic/Latino. Thirty-two percent of the patients, 38% in the LIVDELZI 10 mg arm and 20% in the placebo arm, were enrolled in the US.
At baseline, 18 (14%) of the LIVDELZI-treated patients and 9 (14%) of the placebo-treated patients met at least one of the following criteria: Fibroscan >16.9kPa; historical biopsy or radiological evidence suggestive of cirrhosis; platelet count < 140,000/μL with at least one additional laboratory finding including serum albumin < 3.5 g/dL, INR > 1.3, or TB > 1-time ULN; or clinical determination of cirrhosis by the investigator.
The mean baseline ALP concentration was 314 (Range: 161 to 786) units per liter (U/L), corresponding to 2.7-times ULN. The mean baseline TB concentration was 0.8 (Range: 0.3 to 1.9)mg/dL and was less than or equal to the ULN in 87% of the patients. Other mean baseline liver biochemistries were 48 (Range: 9 to 115) U/L for ALT and 40 (Range: 16 to 94) U/L for AST.
Biochemical Results
The primary endpoint was biochemical response at Month 12, where biochemical response was defined as achieving ALP less than 1.67-times ULN, an ALP decrease of greater than or equal to 15% from baseline, and TB less than or equal to ULN. ALP normalization (i.e., ALP less than or equal to ULN) at Month 12 was a key secondary endpoint. The ULN for ALP was defined as 116 U/L. The ULN for TB was defined as 1.1 mg/dL.
Table 3 presents results at Month 12 for the percentage of patients who achieved biochemical response, achieved each component of biochemical response, and achieved ALP normalization. LIVDELZI demonstrated greater improvement on biochemical response and ALP normalization at Month 12 compared to placebo. Overall, 87% of patients had a baseline of TB concentration less than or equal to ULN. Therefore, improvement in ALP was the main contributor to the biochemical response rate results at Month 12.
Table 3: Percentage of Adult Patients with PBC Achieving Biochemical Response and ALP Normalization at Month 12 in Trial 1a
|
LIVDELZI
10 mg Once
Daily
(N=128) |
Placebo
(N=65) |
Treatment
Difference
% (95% CI)d |
| Biochemical Response Rate, n (%)a,c |
79 (62) |
13 (20) |
42 (28, 53) |
| Components of Biochemical Response |
| ALP less than 1.67-times ULN, n (%) |
84 (66) |
17 (26) |
39 (25, 52) |
| Decrease in ALP of at least 15%, n (%) |
107 (84) |
21 (32) |
51 (37, 63) |
| TB less than or equal to ULN, n (%) |
104 (81) |
50 (77) |
4 (-7, 17) |
| ALP Normalization, n (%)b, c |
32 (25) |
0 (0) |
25 (18, 33) |
a Biochemical response is defined as ALP less than 1.67-times ULN, an ALP decrease of greater than or equal to 15%, and TB less than or equal to ULN.
b ALP normalization is defined as ALP less than or equal to ULN.
c p<0.0001 for LIVDELZI 10 mg versus placebo. P-values were obtained using the Cochran–Mantel–Haenszel test stratified by baseline ALP level (<350 U/L versus ≥350 U/L) and baseline pruritus NRS (<4 versus ≥4).
d 95% unstratified Miettinen and Nurminen confidence intervals (CIs) are provided.
Patients who discontinued treatment prior to Month 12 or who had missing data were considered as non- responders |
Figure 1 shows the mean (95% CI) levels of ALP over 12 months. There was a trend of lower ALP in LIVDELZI arm compared to placebo arm starting at Month 1 through Month 12.
Figure 1: Meana ALP in Adult Patients with PBC over 12 Months in Trial 1a
Biochemical response at Month 3 comparing LIVDELZI as a monotherapy to placebo was evaluated in a pooled analysis of a subset of patients from Trial 1 and another randomized, double-blind, placebo-controlled trial in a similar patient population. There was a trend of improvement on biochemical response at Month 3 in the LIVDELZI monotherapy group compared to the placebo group.
Pruritus
A single-item patient-reported outcome (PRO), the pruritus Numerical Rating Scale (NRS), evaluated patients’ daily worst itching intensity on an 11-point rating scale with scores ranging from 0 (“no itching”) to 10 (“worst itching imaginable”) in Trial 1. The pruritus NRS was administered daily in a 14-day run-in period prior to randomization through Month 6.
Table 4 presents the results of the comparison between LIVDELZI and placebo on the key secondary endpoint evaluating the change from baseline in pruritus score at Month 6 in patients with baseline average pruritus scores greater than or equal to 4. The baseline average pruritus score for each patient was calculated by averaging the pruritus NRS scores administered in the run-in period and on Day 1 before treatment initiation. The pruritus scores at Month 6 for each patient were calculated by averaging the pruritus NRS scores within the last week in the month. Patients treated with LIVDELZI demonstrated greater improvement in pruritus compared with placebo.
Table 4: Change from Baseline in Pruritus Score at Month 6 in PBC Patients with Baseline Average Pruritus Score ≥4 in Trial 1a
|
LIVDELZI 10 mg
Once Daily
(N=49) |
Placebo
(N=23) |
| Baseline Average Pruritus Score, Mean (SD) |
6.1 (1.4) |
6.6 (1.4) |
| Change from Baseline in Pruritus Score at Month 6a |
| Mean (SE) |
-3.2 (0.3) |
-1.7 (0.4) |
| Mean difference vs. Placebo (95% CI) |
-1.5 (-2.5, -0.5)
p=0.0051 |
| a Based on least square means from a mixed-effect model for repeated measures (MMRM) for change from baseline at Months 1 (Week 4), 3 (Week 12), and 6 (Week 26) accounting for baseline average pruritus score, baseline ALP level (<350 U/L versus ALP level ≥350 U/L), treatment arm, time (in months), and treatment-bytime interaction. |