Population Pharmacokinetics of Elagolix in Healthy Women and Women with Endometriosis

Bioequivalence of Elagolix/Estradiol/Norethindrone Acetate Fixed-Dose Combination Product: Phase 1 Results in Healthy Pre- and Postmenopausal Women

Fixed-dose combination (FDC) therapies can enhance patient convenience and adherence to prescribed treatment regimens. Elagolix is a novel oral gonadotropin-releasing hormone receptor antagonist approved for management of moderate to severe pain associated with endometriosis and heavy menstrual bleeding associated with uterine fibroids. Hormonal add-back therapy can attenuate the reversible hypoestrogenic effects of elagolix. An FDC formulation containing elagolix/estradiol (E2)/norethindrone acetate (NETA) 300/1/0.5 mg as the morning dose and an elagolix 300 mg capsule as the evening dose, were evaluated in 2 bioequivalence studies including the effects of food. Study 1 in premenopausal women assessed the bioavailability of the elagolix 300-mg capsule relative to the commercially available elagolix 300-mg tablet. Study 2 in postmenopausal women, elagolix/E2/NETA (300 mg/1 mg/0.5 mg) FDC capsule was assessed relative to the elagolix 300-mg tablet coadministered with E2/NETA 1-mg/0.5-mg tablet, the regimen that was studied in Phase 3 uterine fibroid studies. Under fasting conditions, the test elagolix 300-mg capsule was bioequivalent to the reference elagolix 300-mg tablet. Under fasting conditions, the elagolix/E2/NETA FDC capsule was bioequivalent to the coadministered elagolix 300-mg tablet and E2/NETA 1/0.5-mg tablet. Following administration of elagolix/E2/NETA FDC capsule after a high-fat breakfast, elagolix mean maximum concentration (Cmax) and area under the plasma concentration-time curve (AUC) were 38% and 28% lower, relative to fasting conditions. NETA mean Cmax was 51% lower and AUC from time 0 to infinity was 20% higher, while baseline-adjusted total estrone mean Cmax and AUC were 46% and 14% lower, respectively. No safety concerns were identified. These results enabled bridging the elagolix/E2/NETA FDC capsule.

Safety, Pharmacokinetics, and Pharmacodynamics of SHR7280, a Non-peptide GnRH Antagonist in Premenopausal Women with Endometriosis: A Randomized, Double-Blind, Placebo-Controlled Phase 1 Study

BACKGROUND

Oral gonadotropin-releasing hormone (GnRH) antagonists are promising agents in the treatment of endometriosis-related pain. Here we assessed the safety, pharmacokinetics (PK), and pharmacodynamics (PD) of SHR7280, an oral non-peptide GnRH antagonist in premenopausal women with endometriosis.

METHODS

In the Phase 1 part of the randomized, double-blinded, placebo-controlled, dose-ascending, Phase 1/2 trial, premenopausal women with endometriosis were randomized (4:1) to receive SHR7280 or placebo treatment for 21 consecutive days. The treatment dose started from 200 mg QD, and then increased to 300 mg QD and 200 mg BID. Safety, PK, and PD parameters were assessed.

RESULTS

In total, 30 patients received assigned treatment, 24 with SHR7280 and 6 with placebo. SHR7280 was well tolerated. Adverse events (AEs) were reported in 19 (79.2%, 19/24) patients in the SHR7280 group and 5 (83.3%, 5/6) patients in the placebo group. Most AEs were mild and no severe AEs occurred. SHR7280 showed a rapid absorption, with a time to maximum plasma concentration (Tmax) of 1.0 h, 1.0 h, and 0.8 h for the 200 mg QD, 300 mg QD, and 200 mg BID regimens, respectively. Plasma concentration of SHR7280 was dose dependent. The mean half-life (t1/2) at steady state was 6.9 h, 7.4 h, and 2.8 h, respectively, and little or no accumulation was observed. Pharmacodynamic analysis showed that SHR7280 could effectively suppress estradiol and luteinizing hormone concentrations and prevent progesterone increase in a dose-dependent manner. SHR7280 at doses of 300 mg QD and 200 mg BID could suppress estradiol levels within the desired therapeutic window of 20-50 pg/mL throughout the treatment period.

CONCLUSIONS

SHR7280 showed favorable safety, PK, and PD profiles in the doses of 200 mg QD, 300 mg QD, and 200 mg BID. The results of this study provide evidence to support the further development of SHR7280 as a GnRH antagonist for the treatment of endometriosis-related pain in the subsequent Phase 2 trial.

TRIAL REGISTRY

Trial registration number: Clinicaltrials.gov, identifier: NCT04417972. Trial registration date: 5 June 2020.

Safety, pharmacokinetics, and pharmacodynamics of SHR7280, an oral gonadotropin-releasing hormone antagonist in healthy premenopausal women

Background: Treatment with gonadotropin-releasing hormone (GnRH) antagonists is a powerful strategy to suppress gonadotropin activity in women with sex hormone-dependent disorders. Herein, we provide the safety, pharmacokinetics (PK), and pharmacodynamics (PD) profiles of SHR7280, an oral non-peptide GnRH antagonist in healthy premenopausal women. Methods: In this randomized, double-blinded, placebo-controlled, dose-ascending, phase 1 trial, healthy premenopausal women were randomized to receive SHR7280 or placebo orally. Four doses of SHR7280 (200, 300, 400, and 500 mg BID) were planned. Safety, PK, and PD parameters were evaluated. Results: SHR7280 presented tolerable toxicity and most adverse events were mild in severity. SHR7280 showed rapid onset of action (median T_max ranged from 1.0 to 1.2 h for each dose), and plasma exposure was dose-dependent. PD results showed that SHR7280 300 mg BID and above suppressed estrogen concentration within the estradiol (E₂) treatment window for endometriosis (20-50 pg/ml), inhibited the emergence of the peak of luteinizing hormone (LH) and the concentration of follicle stimulating hormone (FSH), and maintained the concentration of progesterone (P) in an anovulatory state (2 nmol/L). Conclusion: SHR7280 showed favorable safety, PK, and PD profiles in the dose range of 200-500 mg BID in healthy premenopausal women. This study supports the continued clinical development of SHR7280 as a GnRH antagonist for sex hormone-dependent disorders in women. Clinical Trial Registration: https://clinicaltrials.gov/ct2/show/NCT04554043, Identifier NCT04554043.

Greenness assessment of micellar spectrofluorometric approach for determination of Elagolix: application to dosage form, content uniformity and human plasma

Ecological, sensitive, fast and economic approaches are the main aspects in quality control of pharmaceutical products. Elagolix (ELG) is an orally non-peptidic GnRH antagonist, recently approved drug by Food and drug administration in 2018 for treatment of pain associated with endometriosis. A green, and sensitive method was developed and validated for determination of ELG based on micellar spectrofluorometric approach. Many factors were studied to enhance the fluorescence intensity of ELG and the highest sensitivity was obtained upon using 1% Sodium dodecyl sulphate (SDS) at 438 nm after excitation at 270 nm. A linear relationship was obtained over a range of 50-1000 ng mL^-1 between ELG concentration and corresponding fluorescence intensity. The developed method was validated according to ICH guidelines and successfully applied for testing the content uniformity and determination of ELG in pharmaceutical dosage forms with percentage recovery 99.31 ± 1.98. Furthermore, the capability of the method due to its high sensitivity to determine ELG in human plasma with percentage recoveries in a range of 98.54-100.46. The greenness of the method was investigated using three different approaches; Analytical Procedure Index (GAPI), Analytical Eco-Scale and Analytical Greenness Metric (AGREE).

Computational Models for Diagnosing and Treating Endometriosis

Endometriosis is a common but poorly understood disease. Symptoms can begin early in adolescence, with menarche, and can be debilitating. Despite this, people often suffer several years before being correctly diagnosed and adequately treated. Endometriosis involves the inappropriate growth of endometrial-like tissue (including epithelial cells, stromal fibroblasts, vascular cells, and immune cells) outside of the uterus. Computational models can aid in understanding the mechanisms by which immune, hormone, and vascular disruptions manifest in endometriosis and complicate treatment. In this review, we illustrate how three computational modeling approaches (regression, pharmacokinetics/pharmacodynamics, and quantitative systems pharmacology) have been used to improve the diagnosis and treatment of endometriosis. As we explore these approaches and their differing detail of biological mechanisms, we consider how each approach can answer different questions about endometriosis. We summarize the mathematics involved, and we use published examples of each approach to compare how researchers: (1) shape the scope of each model, (2) incorporate experimental and clinical data, and (3) generate clinically useful predictions and insight. Lastly, we discuss the benefits and limitations of each modeling approach and how we can combine these approaches to further understand, diagnose, and treat endometriosis.

Population Pharmacokinetics of Elagolix in Combination with Low-Dose Estradiol/Norethindrone Acetate in Women with Uterine Fibroids

Background and Objectives

Elagolix is an orally active, gonadotropin-releasing hormone receptor antagonist approved for the management of endometriosis-associated pain and heavy menstrual bleeding associated with uterine fibroids. Elagolix population pharmacokinetics and factors affecting elagolix exposure in healthy women and women with endometriosis have been reported previously. The purpose of this study was to extend the population pharmacokinetics model with additional modifications to incorporate data from phase III studies of elagolix with hormonal add-back therapy in women with uterine fibroids.

Methods

Data from 13 clinical studies (a total of 2168 women) consisting of six phase I studies in healthy premenopausal women, four phase III studies in premenopausal women with endometriosis, and three phase III studies in premenopausal women with uterine fibroids were analyzed using a non-linear mixed-effects modeling approach.

Results

Elagolix population pharmacokinetics was best described by a two-compartment model with first-order absorption, lag time in absorption, and first-order elimination. Out of the covariates tested on elagolix apparent clearance, apparent volume of distribution, and/or relative bioavailability, only organic anion transporting polypeptide 1B1 genotype status and body weight had a statistically significant but no clinically meaningful effect on elagolix relative bioavailability and apparent volume of distribution, respectively. There were no clinically meaningful differences in elagolix population pharmacokinetics in healthy women or women with endometriosis or uterine fibroids.

Conclusions

Elagolix population pharmacokinetics modeling did not reveal any patient-related factors or clinical parameters that would require dose adjustments for the approved dosage of 300 mg twice daily with estradiol 1 mg /norethindrone acetate 0.5 mg daily, in women with heavy menstrual bleeding associated with uterine fibroids.

Clinical Trial Registration

ClinicalTrials.gov identifiers: NCT01620528 (EM-1), NCT01760954 (EM-1-Extend), NCT01931670 (EM-2), NCT02143713 (EM-2-Extend), NCT02654054 (UF-1), NCT02691494 (UF-2), NCT0295494 (UF-Extend).

Supplementary Information

The online version contains supplementary material available at 10.1007/s40262-021-01096-w.

Elagolix in the treatment of heavy menstrual bleeding associated with uterine fibroids in premenopausal women

INTRODUCTION

Uterine fibroids (UFs) are the most common benign tumor arising from myometrium of reproductive age women, with significant financial burden estimated in hundreds of billions of dollars. Unfortunately, there are limitations in available long-term treatment options. Thus, there is a large unmet need in the UF space for noninvasive therapeutics.

AREAS COVERED

Authors reviewed the literature available for elagolix; an orally bioavailable, second-generation, non-peptide gonadotropin-releasing hormone (GnRH) antagonist recently approved by the US Food and Drug Administration (FDA) in combination with estradiol/norethindrone acetate for the management of heavy menstrual bleeding associated with UFs in premenopausal women.

EXPERT OPINION

The utility of new-generation oral GnRH-antagonists, such as elagolix, relugolix and linzagolix, is offering a new potential opportunity for the future therapy of UFs: elagolix has been the most studied drug of this class for treating benign gynecological diseases, including endometriosis and UFs, for which it has been US FDA-approved in 2018 and 2020, respectively.

A Personalized Medicine Approach Using Clinical Utility Index and Exposure-Response Modeling Informed by Patient Preferences Data

Selection of a personalized dose for an individual patient can be informed by the patient's preferences, translated as weights on each of the clinically relevant safety and efficacy drug attributes, based on results from a brief patient preference elicitation questionnaire. In this analysis, the weighted attributes were simulated to represent various endometriosis patient profiles. Exposure-response simulations were performed for elagolix, a drug approved for management of moderate to severe pain associated with endometriosis, across a range of plasma exposures corresponding to a range of doses. The results were combined to calculate a personalized clinical utility index. An interactive user-friendly online application was developed and envisioned as a physician's desk tool to personalize the dose selection process based on individual patient preferences. This demonstration should serve as an example of how patient/physician conversation can be facilitated with quantitative tools for personalizing the dose.

Exposure-Safety Analyses Identify Predictors of Change in Bone Mineral Density and Support Elagolix Labeling for Endometriosis-Associated Pain

Elagolix is a novel oral gonadotropin releasing hormone receptor antagonist, that can suppress estradiol in a dose‐dependent manner. It is indicated for management of moderate‐to‐severe pain associated with endometriosis. A population exposure‐response model describing the relationship between elagolix exposure and changes in bone mineral density (BMD) was developed using data from four phase III studies in premenopausal women with endometriosis‐associated pain. Elagolix pharmacokinetic exposure‐dependent changes in BMD were described by an indirect‐response maximum effect (E_max) model through stimulation of bone resorption. African American race, higher body mass index (BMI), and lower type‐I collagen C‐telopeptide concentrations were significantly associated with higher baseline BMD. Higher BMI was significantly associated with higher bone formation rates. Simulations using the final model demonstrated that elagolix 150 mg q.d. dosing for 24 months is predicted to result in −1.45% (−2.04 to −0.814) decrease from baseline in BMD and were used to support corresponding dosing recommendations in the label.

Effect of Elagolix Exposure on Clinical Efficacy End Points in Phase III Trials in Women With Endometriosis-Associated Pain: An Application of Markov Model

Elagolix is an oral gonadotropin‐releasing hormone antagonist approved by the US Food and Drug Administration (FDA) for the management of moderate‐to‐severe pain associated with endometriosis and in combination with estradiol/norethindrone acetate approved for the management of heavy menstrual bleeding associated with uterine leiomyomas (fibroids) in premenopausal women. The objective of this work was to characterize the relationships between elagolix exposures and clinical efficacy response rates for dysmenorrhea (DYS) and nonmenstrual pelvic pain (NMPP) in premenopausal women enrolled in the pivotal phase III studies with moderate‐to‐severe pain associated with endometriosis. Relationships between elagolix average concentrations (C_avg) and efficacy responses (DYS and NMPP) were characterized using a nonlinear mixed‐effects discrete‐time first order Markov modeling approach. Only age was statistically significant for NMPP but not considered clinically relevant. This work indicates that the selection of elagolix dose is not determined based on tested patient demographics, baseline, or endometriosis disease severity measures in covariate analysis. In other words, the work suggests no preference of one regimen over the other to treat endometriosis‐associated pain (DYS or NMPP) for any patient subpopulation based on tested covariate groups.

Clinical Pharmacology of Elagolix: An Oral Gonadotropin-Releasing Hormone Receptor Antagonist for Endometriosis

The clinical pharmacology of elagolix was extensively evaluated in clinical studies in healthy subjects and in women with endometriosis. Elagolix pharmacokinetics (PK) show significant population variability, however they are minimally affected by patients' baseline characteristics and demographics, except for clinically relevant extrinsic and intrinsic factors such as coadministrated strong organic anion transporting polypeptide (OATP) 1B1 inhibitors and severe hepatic impairment, which are contraindications for the use of elagolix. These studies enabled a comprehensive understanding of elagolix mechanism of action and the downstream pharmacodynamic (PD) effects on gonadotropin and ovarian hormones, as well as full characterization of the PK/PD (PKPD) relationships of elagolix at various dosages, including the approved 150 mg once daily and 200 mg twice daily dosing regimens for the management of moderate to severe pain associated with endometriosis. Several model-based analyses have contributed to understanding of the benefit-risk profile of elagolix in patients with endometriosis, through characterization of the exposure relationship with responder rates, with changes in bone mineral density over time, as well as the interaction with coadministered drugs. Collectively, these studies and analyses served as supportive evidence for the effectiveness of the approved dosages and provided general dosing instructions of the first approved oral gonadotropin-releasing hormone receptor antagonist.

Elagolix Suppresses Ovulation in a Dose-Dependent Manner: Results From a 3-Month, Randomized Study in Ovulatory Women

CONTEXT

Elagolix is an oral gonadotropin-releasing hormone (GnRH) antagonist recently approved for the treatment of endometriosis-associated pain and being developed for heavy menstrual bleeding associated with uterine fibroids.

OBJECTIVE

The objective was to evaluate the effects of elagolix on ovulation and ovarian sex hormones.

DESIGN AND SETTING

This was a randomized, open-label, multicenter study.

PARTICIPANTS

Participants were healthy ovulatory women aged 18 to 40 years.

INTERVENTIONS

Elagolix was administered orally for 3 continuous 28-day dosing intervals at 100 to 200 mg once daily (QD), 100 to 300 mg twice daily (BID), and 300 mg BID plus estradiol/norethindrone acetate (E2/NETA) 1/0.5 mg QD.

MAIN OUTCOME MEASURES

The main outcomes measures were ovulation rates measured by transvaginal ultrasound, progesterone concentrations, and hormone suppression.

RESULTS

Elagolix suppressed ovulation in a dose-dependent manner. The percentage of women who ovulated was highest at 100 mg QD (78%), intermediate at 150 and 200 mg QD and 100 mg BID (47%-57%), and lowest at 200 and 300 mg BID (32% and 27%, respectively). Addition of E2/NETA to elagolix 300 mg BID further suppressed the ovulation rate to 10%. Elagolix also suppressed luteinizing hormone and follicle stimulating hormone in a dose-dependent manner, leading to dose-dependent suppression of estradiol and progesterone. Elagolix had no effect on serum biomarker of ovarian reserve, and reduced endometrial thickness compared to the screening cycle.

CONCLUSION

Women being treated with elagolix may ovulate and should use effective methods of contraception. The rate of ovulation was lowest with elagolix 300 mg BID plus E2/NETA 1/0.5 mg QD.

Clinical evaluation of the oral gonadotropin-releasing hormone-antagonist elagolix for the management of endometriosis-associated pain

Endometriosis is an estrogen-dependent chronic inflammatory disease associated with pelvic pain symptoms that are often severe, mainly dysmenorrhea, nonmenstrual pelvic pain and dyspareunia. This condition is also associated with peripheral and central sensitization. The current medical treatment options for endometriosis-associated pain are limited. Recently, the US FDA approved the novel, oral, nonpeptide gonadotropin-releasing hormone antagonist elagolix for the management of moderate to severe endometriosis-associated pain. Elagolix produces dose-dependent estrogen suppression, from partial suppression at lower doses to nearly full suppression at higher doses. This review article summarizes the current understanding of the pathophysiology of endometriosis, with a focus on the role of estrogen and the mechanisms of pain symptoms, and reviews the clinical development of elagolix in women with endometriosis-associated pain.

Elagolix: First Global Approval

Elagolix (ORILISSA™), an orally bioavailable, second-generation, non-peptide gonadotropin-releasing hormone (GnRH) receptor antagonist, is being developed AbbVie and Neurocrine Biosciences for the treatment of reproductive hormone-dependent disorders in women. In July 2018, the US FDA approved elagolix tablets for the management of moderate to severe pain associated with endometriosis. This approval was based on positive results in two replicate phase III trials; additional phase III trials in the USA, Canada and Puerto Rico are currently evaluating elagolix as both monotherapy and in combination with low-dose hormone add-back therapy in the same indication. Elagolix with and without low-dose hormone add-back therapy is also undergoing phase III clinical development for heavy menstrual bleeding associated with uterine fibroids in the aforementioned locations. This article summarizes the milestones in the development of elagolix leading to its first approval for the management of moderate to severe pain associated with endometriosis.

Elagolix Pharmacokinetic Profiles in Women With Renal or Hepatic Impairment

The aim of these studies was to assess the safety and pharmacokinetics of elagolix, an oral nonpeptide gonadotropin-releasing hormone antagonist following oral administration in women with renal or hepatic impairment. Two phase 1 studies were conducted in adult women with normal renal function versus renal impairment (reduced study), and normal hepatic function versus hepatic impairment (full study design). All women received a single dose of elagolix 200 mg (renal) or 150 mg (hepatic). Intensive pharmacokinetic blood samples were collected. Elagolix exposures were comparable in women with normal renal function and those with moderate/severe renal impairment or end-stage renal disease. Elagolix exposures also appeared to be similar in women with normal hepatic function and women with mild hepatic impairment. Elagolix area under the curve in women with moderate hepatic impairment and with severe hepatic impairment was approximately 3-fold and 7-fold higher than in women with normal hepatic function. The adverse event incidence was low, with the main events being mild nausea and headache. No dosage adjustment was needed in women with renal impairment or women with mild hepatic impairment. Although an elagolix dose of 150 mg once daily may be used in women with moderate hepatic impairment for up to 6 months, this elagolix dose should not be used in women with severe hepatic impairment.