Low-Dose Elagolix for the Treatment of Heavy Menstrual Bleeding in Patients With Uterine Leiomyomas: A Randomized Controlled Trial.

OBJECTIVE: To evaluate the safety and efficacy of elagolix 150 mg once-daily monotherapy in patients with heavy menstrual bleeding associated with uterine leiomyomas. METHODS: A phase 4, randomized, double-blind, placebo-controlled, 6-month treatment study was conducted in premenopausal patients aged 18-51 years with heavy menstrual bleeding (defined as menstrual blood loss greater than 80 mL during one menstrual cycle) associated with uterine leiomyomas. Patients were randomized 2:1 to receive elagolix 150 mg once daily or placebo. The primary endpoint was reduction in menstrual blood loss volume to less than 80 mL at the final month and at least a 50% reduction in menstrual blood loss volume from baseline to the final month. RESULTS: Of 82 randomized patients, 54 received elagolix 150 mg and 28 received placebo. With elagolix, 49.4% (95% CI 35.1-63.8%) of patients met the primary endpoint, compared with 23.3% (95% CI 7.2-39.5%) of patients who received placebo ( P =.035). Statistically significant differences between elagolix and placebo in mean reduction of menstrual blood loss from baseline were seen as early as month 1 ( P <.05 for months 1-3 and 5). Significantly more patients receiving elagolix experienced suppression of bleeding compared with placebo ( P =.036). Greater improvements were observed in the elagolix group (vs placebo) in the proportion of patients with amenorrhea, in hemoglobin concentrations, and in health-related quality of life. No serious or severe adverse events were reported for elagolix, compared with 7.1% of participants in the placebo group having serious adverse events (coronavirus disease 2019 [COVID-19] n=1, enlarged uvula n=1). Three patients (5.6%) discontinued elagolix due to adverse events. CONCLUSION: Elagolix 150 mg once-daily monotherapy significantly improved heavy menstrual bleeding associated with uterine leiomyomas compared with placebo in premenopausal patients. Treatment with elagolix 150 mg once daily was generally well-tolerated in this study, with no new safety signals. FUNDING SOURCE: AbbVie Inc. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov , NCT03886220.

Phase 2, double-blind, randomized, placebo-controlled study of the safety and efficacy of elagolix in women with polycystic ovary syndrome.

Objective: Evaluate the efficacy and safety of elagolix, a GnRH antagonist, to treat polycystic ovarian syndrome (PCOS). Design: A phase 2, multicenter, double-blind, randomized, placebo-controlled trial. Setting: Outpatient and academic medical centers. Patients: One hundred fourteen women with PCOS (aged 18-35 years, body mass index 18.5-38 kg/m2). Interventions: Patients were randomized 2:2:2:2:2:3 to elagolix (25 mg twice daily, 50 mg once daily, 75 mg twice daily, 150 mg once daily, and 300 mg twice daily) or placebo. Main Outcome Measures: The primary endpoint was menstrual cycle normalization (defined as 2 menstrual cycles 21-35 days in length during the 4-month treatment period). The secondary endpoint was change from baseline to week 1 in the area under the luteinizing hormone (LH) serum concentration-time curve (AUC). Additional endpoints included change from baseline in serum hormone levels. Results: No significant improvement in restoring normal menstrual cycles was observed in treated subjects; 3 of 114 patients met the primary endpoint. Six patients experienced progesterone elevations indicative of ovulation. The LH levels decreased from baseline to week 16, and LH AUC was significantly reduced from baseline to week 1 in all elagolix treatment groups (P<.1 vs placebo). Follicle-stimulating hormone (FSH) levels generally remained stable through week 16, with no significant differences in FSH AUCs. Serum estradiol and testosterone concentrations were consistently reduced from baseline in all elagolix dose groups compared with placebo. Adverse event rates were similar across treatment groups. Conclusions: Elagolix treatment did not normalize the ovulatory cycle in patients with PCOS. Clinical Trial Registration Number: NCT03951077.

Validation of a quantitative systems pharmacology model of calcium homeostasis using elagolix Phase 3 clinical trial data in women with endometriosis.

Elagolix is a novel, oral gonadotropin-releasing hormone receptor antagonist indicated for the management of moderate to severe pain associated with endometriosis and heavy menstrual bleeding associated with uterine fibroids. Consistent with its mechanism of action, elagolix exhibited dose-dependent suppression of estradiol (E2) in clinical studies. A dose-response model that describes the relationship between elagolix dosages and average E2 levels was combined with a previously published quantitative systems pharmacology (QSP) model of calcium homeostasis to predict bone mineral density (BMD) changes during and following elagolix treatment. In the QSP model, changes in E2 levels were linked to downstream changes in markers of bone resorption (carboxyterminal cross-linked telopeptide of type 1 collagen [CTX]), formation (N-terminal propeptide of type 1 procollagen [P1NP]) and BMD. The BMD, CTX, and P1NP predictions by the QSP model were validated against observed data from four phase III clinical trials of elagolix in premenopausal women with endometriosis. BMD, CTX, and P1NP were successfully described by the QSP model, without any model fitting, suggesting that the model was validated for further predictions of elagolix effects on BMD. Simulations using the validated QSP model demonstrated that elagolix 150 mg once daily dosing for 24 months is predicted to result in -0.91% change from baseline in lumbar spine BMD. The QSP model simulation results were part of the totality of evidence to support the approved duration of therapy for elagolix 150 mg once daily in patients with endometriosis.

Pharmacokinetic and Pharmacodynamic Profiles of Ethinylestradiol/Norgestimate Combination or Norethindrone upon Coadministration with Elagolix 150 mg Once Daily in Healthy Premenopausal Women.

BACKGROUND: Two pharmacokinetic/pharmacodynamic studies were conducted to evaluate the potential drug-drug interaction between elagolix, an oral gonadotropin-releasing hormone receptor antagonist, and an oral contraceptive (ethinylestradiol [EE] 0.035 mg and norgestimate 0.18/0.215/0.25 mg) or progestin-only contraceptive (norethindrone 0.35 mg) in healthy premenopausal women. METHODS: These phase I studies used a two-period, sequential design, where period 1 included treatment with oral contraceptives, followed by period 2 with contraceptives coadministered with elagolix 150 mg once daily. RESULTS: In study 1, pharmacokinetic exposures for EE in period 2 increased by 30% and the norgestimate metabolites decreased by approximately 15% when coadministered with elagolix. Mean hormone exposure appeared lower for follicle-stimulating hormone (FSH; 31%), luteinizing hormone (LH; 38%), and estradiol (E2; 16%). The percentage of women with consecutive progesterone (P) concentrations above 5 nmol/L was similar in both periods. Norethindrone pharmacokinetic exposures were comparable in both periods. The hormone exposure for LH and FSH was similar, and mean E2 exposure was 32% lower in period 2. The percentage of subjects with consecutive ovulatory P concentrations was also similar in both periods (study 2). Safety and tolerability profiles were unremarkable in both studies. CONCLUSIONS: Coadministration of elagolix 150 mg once daily with oral contraceptives containing EE and norgestimate, or norethindrone, resulted in small pharmacokinetic changes in the oral contraceptive components. Similar or lower FSH, LH, and E2 exposures were observed during coadministration, with ovulatory P concentrations also comparable in both periods. The pharmacodynamic profiles of the oral contraceptives were maintained when coadministered with elagolix.

Assessment of Clinical Drug-Drug Interactions of Elagolix, a Gonadotropin-Releasing Hormone Receptor Antagonist.

Elagolix is an oral gonadotropin-releasing hormone receptor antagonist indicated for the management of endometriosis-associated pain and in combination with estradiol/norethindrone acetate indicated for the management of heavy menstrual bleeding associated with uterine leiomyomas (fibroids) in premenopausal women. Elagolix coadministered with estradiol/norethindrone acetate is in late-stage development for the management of heavy menstrual bleeding associated with uterine fibroids. Based on the in vitro profile of elagolix metabolism and disposition, 9 drug-drug interaction (DDI) studies evaluating the victim and perpetrator characteristics of elagolix were conducted in 144 healthy volunteers. As a victim of cytochrome P450 (CYPs) and transporter-mediated DDIs, elagolix area under the curve (AUC) increased by ∼2-fold following coadministration with ketoconazole and by ∼5- and ∼2-fold with single and multiple doses of rifampin, respectively. As a perpetrator, elagolix decreased midazolam AUC (90% confidence interval) by 54% (50%-59%) and increased digoxin AUC by 32% (23%-41%). Elagolix decreased rosuvastatin AUC by 40% (29%-50%). No clinically significant changes in exposure on coadministration with sertraline or fluconazole occurred. A elagolix 150-mg once-daily regimen should be limited to 6 months with strong CYP3A inhibitors and rifampin because of the potential increase in bone mineral density loss, as described in the drug label. A 200-mg twice-daily regimen is recommended for no more than 1 month with strong CYP3A inhibitors and not recommended with rifampin. Elagolix is contraindicated with strong organic anion transporter polypeptide B1 inhibitors (eg, cyclosporine and gemfibrozil). Consider increasing the doses of midazolam and rosuvastatin when coadministered with elagolix, and individualize therapy based on patient response. Clinical monitoring is recommended for P-glycoprotein substrates with a narrow therapeutic window (eg, digoxin). Dose adjustments are not required for sertraline, fluconazole, bupropion (or any CYP2B6 substrate), or elagolix when coadministered.

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 (Emax ) 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 (Cavg ) 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.

Quantitative Assessment of Elagolix Enzyme-Transporter Interplay and Drug-Drug Interactions Using Physiologically Based Pharmacokinetic Modeling.

INTRODUCTION: Elagolix is approved for the management of moderate-to-severe pain associated with endometriosis. The aim of this analysis was to develop a physiologically based pharmacokinetic (PBPK) model that describes the enzyme-transporter interplay involved in the disposition of elagolix and to predict the magnitude of drug-drug interaction (DDI) potential of elagolix as an inhibitor of P-glycoprotein (P-gp) and inducer of cytochrome P450 (CYP) 3A4. METHODS: A PBPK model (SimCYP® version 15.0.86.0) was developed using elagolix data from in vitro, clinical PK and DDI studies. Data from DDI studies were used to quantify contributions of the uptake transporter organic anion transporting polypeptide (OATP) 1B1 and CYP3A4 in the disposition of elagolix, and to quantitatively assess the perpetrator potential of elagolix as a CYP3A4 inducer and P-gp inhibitor. RESULTS: After accounting for the interplay between elagolix metabolism by CYP3A4 and uptake by OATP1B1, the model-predicted PK parameters of elagolix along with the DDI AUC∞ and Cmax ratios, were within 1.5-fold of the observed data. Based on model simulations, elagolix 200 mg administered twice daily is a moderate inducer of CYP3A4 (approximately 56% reduction in midazolam AUC∞). Simulations of elagolix 150 mg administered once daily with digoxin predicted an increase in digoxin Cmax and AUC∞ by 68% and 19%, respectively. CONCLUSIONS: A PBPK model of elagolix was developed, verified, and applied to characterize the disposition interplay between CYP3A4 and OATP1B1, and to predict the DDI potential of elagolix as a perpetrator under dosing conditions that were not tested clinically. PBPK model-based predictions were used to support labeling language for DDI recommendations of elagolix.

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.

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.

Long-Term Outcomes of Elagolix in Women With Endometriosis: Results From Two Extension Studies.

OBJECTIVE: To evaluate the efficacy and safety of elagolix, an oral, nonpeptide gonadotropin-releasing hormone antagonist, over 12 months in women with endometriosis-associated pain. METHODS: Elaris Endometriosis (EM)-III and -IV were extension studies that evaluated an additional 6 months of treatment after two 6-month, double-blind, placebo-controlled phase 3 trials (12 continuous treatment months) with two elagolix doses (150 mg once daily and 200 mg twice daily). Coprimary efficacy endpoints were the proportion of responders (clinically meaningful pain reduction and stable or decreased rescue analgesic use) based on average monthly dysmenorrhea and nonmenstrual pelvic pain scores. Safety assessments included adverse events, clinical laboratory tests, and endometrial and bone mineral density assessments. The power of Elaris EM-III and -IV was based on the comparison to placebo in Elaris EM-I and -II with an expected 25% dropout rate. RESULTS: Between December 28, 2012, and October 31, 2014 (Elaris EM-III), and between May 27, 2014, and January 6, 2016 (Elaris EM-IV), 569 participants were enrolled. After 12 months of treatment, Elaris EM-III responder rates for dysmenorrhea were 52.1% at 150 mg once daily (Elaris EM-IV 550.8%) and 78.2% at 200 mg twice daily (Elaris EMIV 575.9%). Elaris EM-III nonmenstrual pelvic pain responder rates were 67.5% at 150 mg once daily (Elaris EM-IV 566.4%) and 69.1% at 200 mg twice daily (Elaris EM-IV 567.2%)."After 12 months of treatment, Elaris EM-III dyspareunia responder rates were 45.2% at 150 mg once daily (Elaris EM-IV=45.9%) and 60.0% at 200 mg twice daily (Elaris EM-IV=58.1%). Hot flush was the most common adverse event. Decreases from baseline in bone mineral density and increases from baseline in lipids were observed after 12 months of treatment. There were no adverse endometrial findings. CONCLUSION: Long-term elagolix treatment provided sustained reductions in dysmenorrhea, nonmenstrual pelvic pain, and dyspareunia. The safety was consistent with reduced estrogen levels and no new safety concerns were associated with long-term elagolix use. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, NCT01760954 and NCT02143713.

Population Pharmacokinetics of Elagolix in Healthy Women and Women with Endometriosis.

INTRODUCTION: Elagolix is a novel, orally active, non-peptide, competitive gonadotropin-releasing hormone (GnRH) receptor antagonist in development for the management of endometriosis with associated pain and heavy menstrual bleeding due to uterine fibroids. The pharmacokinetics of elagolix have been well-characterized in phase I studies; however, elagolix population pharmacokinetics have not been previously reported. Therefore, a robust model was developed to describe elagolix population pharmacokinetics and to evaluate factors affecting elagolix pharmacokinetic parameters. METHODS: The data from nine clinical studies (a total of 1624 women) were included in the analysis: five phase I studies in healthy, premenopausal women and four phase III studies in premenopausal women with endometriosis. RESULTS: Elagolix population pharmacokinetics were best described by a two-compartment model with a lag time in absorption. Of the 15 covariates tested for effect on elagolix apparent clearance (CL/F) and/or volume of distribution only one covariate, organic anion transporting polypeptide (OATP) 1B1 genotype status, had a statistically significant, but not clinically meaningful, effect on elagolix CL/F. CONCLUSION: Elagolix pharmacokinetics were not affected by patient demographics and were similar between healthy women and women with endometriosis. Clinical Trial Registration Numbers NCT01403038, NCT01620528, NCT01760954, NCT01931670, NCT02143713.

Elagolix for the management of heavy menstrual bleeding associated with uterine fibroids: results from a phase 2a proof-of-concept study.

OBJECTIVE: To evaluate the safety and efficacy of elagolix vs. placebo and elagolix with low-dose E2/progestogen add-back therapy. DESIGN: Proof-of-concept, dose-ranging, multiple-cohort study. SETTING: Clinics. PATIENT(S): Premenopausal women with fibroids and heavy menstrual bleeding (menstrual blood loss [MBL] >80 mL per cycle). INTERVENTION(S): Three months' treatment with elagolix alone: 100 mg twice daily (BID), 200 mg BID, 300 mg BID, 400 mg once daily (QD), or 600 mg QD (all but the 600 mg QD arm were placebo controlled); or elagolix plus add-back therapy: 200 mg BID plus continuous low-dose E2 0.5 mg/norethindrone acetate 0.1 mg or elagolix 300 mg BID plus E2 1 mg continuously and cyclical P 200 mg. MAIN OUTCOME MEASURE(S): Least-squares mean percentage change in MBL; adverse events (AEs). RESULT(S): Mean age was 41.8 years; 73.8% were black; mean baseline MBL was 267 mL. Of randomized women (elagolix alone, n = 160; placebo, n = 50; elagolix with add-back therapy, n = 61), 228 of 271 completed the 3-month treatment period. The MBL percentage change from baseline to last 28 days was significantly greater with elagolix alone (range, -72% to -98%; dose-dependent reduction was highest with 300 mg BID) vs. placebo (range, -8% to -41%); mean percentage changes with add-back regimens were -80% to -85%. Overall AEs were dose independent (elagolix alone, 70.0%-81.3%) but lower with placebo (56.0%) and add-back regimens (55.6%-70.6%). Hot flush was the most common AE (elagolix alone, 45.5%-62.5%; placebo, 12.0%; add-back regimens, 18.5%-26.5%). CONCLUSION(S): Elagolix significantly reduced heavy menstrual bleeding in women with fibroids. Low-dose add-back regimens substantially reduced flushing. CLINICAL TRIAL REGISTRATION NUMBER: NCT01441635.

Treatment of Endometriosis-Associated Pain with Elagolix, an Oral GnRH Antagonist.

BACKGROUND: Endometriosis is a chronic, estrogen-dependent condition that causes dysmenorrhea and pelvic pain. Elagolix, an oral, nonpeptide, gonadotropin-releasing hormone (GnRH) antagonist, produced partial to nearly full estrogen suppression in previous studies. METHODS: We performed two similar, double-blind, randomized, 6-month phase 3 trials (Elaris Endometriosis I and II [EM-I and EM-II]) to evaluate the effects of two doses of elagolix - 150 mg once daily (lower-dose group) and 200 mg twice daily (higher-dose group) - as compared with placebo in women with surgically diagnosed endometriosis and moderate or severe endometriosis-associated pain. The two primary efficacy end points were the proportion of women who had a clinical response with respect to dysmenorrhea and the proportion who had a clinical response with respect to nonmenstrual pelvic pain at 3 months. Each of these end points was measured as a clinically meaningful reduction in the pain score and a decreased or stable use of rescue analgesic agents, as recorded in a daily electronic diary. RESULTS: A total of 872 women underwent randomization in Elaris EM-I and 817 in Elaris EM-II; of these women, 653 (74.9%) and 632 (77.4%), respectively, completed the intervention. At 3 months, a significantly greater proportion of women who received each elagolix dose met the clinical response criteria for the two primary end points than did those who received placebo. In Elaris EM-I, the percentage of women who had a clinical response with respect to dysmenorrhea was 46.4% in the lower-dose elagolix group and 75.8% in the higher-dose elagolix group, as compared with 19.6% in the placebo group; in Elaris EM-II, the corresponding percentages were 43.4% and 72.4%, as compared with 22.7% (P<0.001 for all comparisons). In Elaris EM-I, the percentage of women who had a clinical response with respect to nonmenstrual pelvic pain was 50.4% in the lower-dose elagolix group and 54.5% in the higher-dose elagolix group, as compared with 36.5% in the placebo group (P<0.001 for all comparisons); in Elaris EM-II, the corresponding percentages were 49.8% and 57.8%, as compared with 36.5% (P=0.003 and P<0.001, respectively). The responses with respect to dysmenorrhea and nonmenstrual pelvic pain were sustained at 6 months. Women who received elagolix had higher rates of hot flushes (mostly mild or moderate), higher levels of serum lipids, and greater decreases from baseline in bone mineral density than did those who received placebo; there were no adverse endometrial findings. CONCLUSIONS: Both higher and lower doses of elagolix were effective in improving dysmenorrhea and nonmenstrual pelvic pain during a 6-month period in women with endometriosis-associated pain. The two doses of elagolix were associated with hypoestrogenic adverse effects. (Funded by AbbVie; Elaris EM-I and EM-II ClinicalTrials.gov numbers, NCT01620528 and NCT01931670 .).

Dose-Dependent Suppression of Gonadotropins and Ovarian Hormones by Elagolix in Healthy Premenopausal Women.

Context: Elagolix is a nonpeptide, oral gonadotropin-releasing hormone (GnRH) antagonist being developed for sex-hormone-dependent diseases in women. Objective: We evaluated the pharmacokinetics and pharmacodynamics of elagolix. Design, Setting, and Participants: This study was a randomized, double-blind, placebo-controlled, multiple-ascending dose study in 45 healthy premenopausal women at a research unit. Interventions: Elagolix [150 mg once daily or 100, 200, 300, or 400 mg twice daily (BID)] or placebo was administered for 21 days. Main Outcome Measures: Main outcome measures were elagolix pharmacokinetics, suppression of gonadotropics [follicle-stimulating hormone (FSH), luteinizing hormone (LH)] and ovarian hormones [estradiol (E2), progesterone (P)], and adverse events. Results: Elagolix was rapidly absorbed after oral dosing, reaching maximum concentrations at 1.0 to 1.5 hours, with a half-life of 4 to 6 hours. FSH, LH, and E2 were suppressed within hours of elagolix administration on day 1. Dose-dependent suppression of E2 was observed, with maximum suppression achieved with elagolix 200 mg BID. Dose-dependent suppression of FSH and LH was also observed, with maximal or near-maximal suppression achieved at 300 mg BID and 200 mg BID, respectively. At elagolix doses ≥100 mg BID, P concentrations remained at anovulatory levels throughout 21 days of dosing. The most frequently reported adverse events were headache and hot flush. Conclusions: Elagolix administration allows for modulation of gonadotropin and ovarian hormone concentrations, from partial suppression at lower doses to nearly full suppression at higher doses. The results of this study provide a rationale for elagolix dose selection for treatment of sex hormone-dependent diseases in women.

Pharmacokinetic enhancement in HIV antiretroviral therapy: a comparison of ritonavir and cobicistat.

Inhibition of the cytochrome p450 3A4 enzyme system leads to increases in plasma concentrations of coadministered antiretroviral agents - a concept known as pharmacokinetic boosting. Ritonavir and cobicistat are potent inhibitors of cytochrome p450 3A4. Ritonavir was initially developed as an HIV protease inhibitor, but is currently used primarily as a pharmacokinetic boosting agent for other HIV and hepatitis C protease inhibitors. Cobicistat is a boosting agent for the integrase inhibitor elvitegravir and the protease inhibitors atazanavir and darunavir. Phase III data showed that atazanavir + cobicistat + tenofovir/emtricitabine had non-inferior efficacy and resulted in similar CD4 T-cell count increases to atazanavir + ritonavir + tenofovir/emtricitabine. The tolerability, gastrointestinal, and lipid profile of the cobicistat-containing regimen was comparable with the ritonavir-containing regimen. Primary HIV protease resistance mutations were not selected in either ritonavir or cobicistat arm virologic failures. Cobicistat-containing regimens have consistently shown higher serum creatinine increases and creatinine clearance decreases compared with ritonavir, and accurate assessment of glomerular filtration in the presence of cobicistat could only be made by using exogenous markers such as iohexol. Drugs contraindicated with cobicistat are consistent with those contraindicated with ritonavir-containing protease inhibitor regimens with respect to cytochrome p450 3A interactions. Information in this review may help clinicians assess the benefits and limitations of currently available pharmacokinetic enhancers when selecting the most appropriate treatment for their patients.

Pharmacokinetics and safety of the lopinavir/ritonavir tablet 500/125 mg twice daily coadministered with efavirenz in healthy adult participants.

A study was conducted in healthy adults (n = 19) to evaluate the pharmacokinetics of lopinavir/ritonavir when coadministered with efavirenz. Participants were administered lopinavir/ritonavir 400/100 mg alone twice daily (bid) from the morning of day 1 through the morning of day 10, and then lopinavir/ritonavir 500/125 mg bid was coadministered with efavirenz 600 mg every evening (qhs) from the evening of day 10 through day 20. Lopinavir and ritonavir exposures when administered alone versus with efavirenz were determined on days 10 and 20 and compared using point estimates and 90% confidence intervals. The point estimates for the ratios of lopinavir maximum observed plasma concentration (C(max)), plasma concentration prior to morning dosing (C(trough)), and area under the plasma concentration-time curve over a dosing interval (AUC(12)) were 1.121, 0.954, and 1.060, respectively. The lopinavir/ritonavir dose of 500/125 mg bid administered with efavirenz most closely approximates the pharmacokinetic exposure of lopinavir/ritonavir 400/100 mg bid administered alone.

A limited sampling model for estimation of total and unbound mycophenolic acid (MPA) area under the curve (AUC) in hematopoietic cell transplantation (HCT).

OBJECTIVES: Renal transplant patients with suboptimal mycophenolic acid (MPA) areas under the curves (AUCs) are at greater risk of acute rejection. In hematopoietic cell transplantation, a low MPA AUC is also associated with a higher incidence of acute graft versus host disease. Therefore, a limited sampling model was developed and validated to simultaneously estimate total and unbound MPA AUC0-12 in hematopoietic cell transplantation patients. METHODS: Intensive pharmacokinetic sampling was performed at steady state between days 3 to 7 posttransplant in 73 adult subjects while receiving prophylactic mycophenolate mofetil 1 g per 12 hours orally or intravenously plus cyclosporine. Total and unbound MPA plasma concentrations were measured, and total and unbound AUC0-12 was determined using noncompartmental analysis. Regression analysis was then performed to build IV and PO, total and unbound AUC0-12 models from the first 34 subjects. The predictive performance of these models was tested in the next 39 subjects. RESULTS: Trough concentrations poorly estimate observed total and unbound AUC0-12 (r<0.48). A model with 3 concentrations (2-, 4-, and 6-hour post start of infusion) best estimated observed total and unbound AUC0-12 after IV dosing (r>0.99). Oral total and unbound AUC0-12 was more difficult to estimate and required at least 4 concentrations (0-, 1-, 2-, and 6-hour post dose) in the model (r>0.85). The predictive performance of the final models was good. Eighty-three percent of IV and 70% of PO AUC0-12 predictions fell within +/-20% of the observed values without significant bias. CONCLUSION: Trough MPA concentrations do not accurately describe MPA AUC0-12. Three intravenous (2-, 4-, 6-hour post start of infusion) or 4 oral (0-, 1-, 2-, and 6-hour post dose) MPA plasma concentrations measured over a 12-hour dosing interval will estimate the total and unbound AUC0-12 nearly as well as intensive pharmacokinetic sampling with good precision and low bias. This approach simplifies AUC0-12 targeting of MPA post hematopoietic cell transplantation.

Relationship of mycophenolic acid exposure to clinical outcome after hematopoietic cell transplantation.

Mycophenolate mofetil is used increasingly to provide immunosuppression after nonmyeloablative allogeneic hematopoietic cell transplantation. There is wide variability in the pharmacokinetics of mycophenolic acid (MPA), the active metabolite, and low concentrations are associated with rejection after organ transplantation. We hypothesized that low MPA was associated with poorer engraftment and a higher incidence of acute graft versus host disease. We evaluated the pharmacokinetics in 87 adult subjects undergoing nonmyeloablative-related and nonmyeloablative-unrelated hematopoietic cell transplantation who were receiving 1 g mycophenolate mofetil orally or intravenously every 12 hours plus cyclosporine (INN, ciclosporin). Subjects with an unbound MPA area under the curve (AUC) from 0 to 6 hours of less than 150 ng . h/mL had a higher cumulative incidence of grade II-IV acute graft versus host disease than subjects with a greater AUC (68% versus 40%, P = .02). An unbound AUC from 0 to 12 hours of less than 300 ng . h/mL was also associated with more frequent acute graft versus host disease (58% versus 35%, P = .05). There was no association between graft versus host disease and trough concentrations (P < or = .62). A higher cumulative incidence of engraftment was associated with total MPA trough concentrations greater than 1 microg/mL (P < .01). All engraftment failures occurred in the cord blood recipients. About one half of subjects were below the unbound AUC target after oral dosing with nearly a 5-fold variability in AUC. Intravenous dosing achieved unbound targets better than oral dosing. The current practice of dosing with 1 g twice daily provides inadequate plasma concentrations in many patients, and doses of at least 3 g/d are likely necessary. Therapeutic monitoring of MPA concentrations with dose adjustment into the therapeutic target appears to be necessary for the most effective use of mycophenolate mofetil.