Linzagolix with and without hormonal add-back therapy for the treatment of symptomatic uterine fibroids: two randomised, placebo-controlled, phase 3 trials.

BACKGROUND: Uterine fibroids are common non-cancerous neoplasm that cause heavy menstrual bleeding and other signs. Linzagolix is an oral gonadotropin-releasing hormone receptor antagonist taken once per day that dose-dependently suppresses gonadal steroids and might reduce uterine-fibroid-associated signs. Two phase 3 trials were conducted to confirm the efficacy and safety of linzagolix at full-suppression (200 mg) and partial-suppression (100 mg) doses with or without hormonal add-back therapy (1 mg oestradiol and 0·5 mg norethisterone acetate) compared with placebo for the treatment of symptomatic uterine fibroids. METHODS: PRIMROSE 1 and PRIMROSE 2 were identical 52-week, randomised, parallel, double-blind, placebo-controlled, phase 3 trials conducted at clinics in the USA (PRIMROSE 1) and Europe and the USA (PRIMROSE 2). Eligible women with uterine fibroid-associated heavy menstrual bleeding (menstrual blood loss >80 mL per cycle) were randomly assigned in a 1:1:1:1:1 ratio to one of five masked treatments: (1) placebo, (2) 100 mg linzagolix per day alone, (3) 100 mg linzagolix per day with once-per-day hormonal add-back therapy (1 mg oestradiol and 0·5 mg norethisterone acetate), (4) 200 mg linzagolix per day alone, or (5) 200 mg linzagolix per day with once-per-day hormonal add-back therapy (1 mg oestradiol and 0·5 mg norethisterone acetate). The primary endpoint was a response (menstrual blood loss ≤80 mL and ≥50% reduction from baseline) at 24 weeks in women who received at least one dose of treatment and did not meet any exclusion criteria based on predosing assessments. These trials are registered with ClinicalTrials.gov (NCT03070899 and NCT03070951). The trials have been completed. FINDINGS: Between May, 2017, and October, 2020, in PRIMROSE 1, 574 women were enrolled, of which 48 discontinued and 15 were excluded; therefore, 511 women were included in the full analysis set; and in PRIMROSE 2, 535 women were enrolled, of which 24 did not receive the study drug and ten women were excluded from the study, resulting in 501 women being included in the full analysis set. In both trials, a significantly higher proportion of women had a reduction in heavy menstrual bleeding in all linzagolix (with or without add-back therapy) treatment groups compared with the placebo group (p≤0·003). In PRIMROSE 1, the response rates were 56·4% (95% CI 45·8-66·6%) in the 100 mg group, 66·4% (56·6-75·2%) in the 100 mg plus add-back therapy group, 71·4% (61·8-79·8%) in the 200 mg group, and 75·5% (66·0-83·5%) in the 200 mg plus add-back therapy group, compared with 35·0% (25·8-45·0%) in the placebo group. In PRIMROSE 2, the response rates were 56·7% (46·3-66·7%) in the 100 mg group, 77·2% (67·8-85·0%) in the 100 mg plus add-back therapy group, 77·7% (68·4-85·3%) in the 200 mg group, and 93·9% (87·1-97·7%) in the 200 mg plus add-back therapy group, compared with 29·4% (20·8-39·3%) with placebo. The most common adverse events up to 24 weeks were hot flushes (35% of participants in PRIMROSE 1 and 32% in PRIMROSE 2 with linzagolix [200 mg] alone and 3-14% in all other groups). INTERPRETATION: Linzagolix (100 mg or 200 mg) with or without add-back therapy significantly reduced heavy menstrual bleeding. Partial suppression with once-per-day linzagolix (100 mg) without add-back therapy potentially provides a unique option for the chronic treatment of symptomatic uterine fibroids in women who cannot or do not want to take concomitant hormonal add-back therapy. FUNDING: ObsEva.

A model-based analysis to guide gonadotropin-releasing hormone receptor antagonist use for management of endometriosis.

AIMS: To identify linzagolix doses, an oral GnRH receptor antagonist, that effectively lower oestradiol (E2) to relieve endometriosis-related pelvic pain without compromising bone health. METHODS: Integrated statistical, pharmacokinetic-pharmacodynamic and systems pharmacology models were developed from Phase 1 and 2 clinical trial data in healthy volunteers and patients, receiving linzagolix 25-200 mg daily or placebo, and analysed simultaneously. The main outcome measures were pelvic pain scores for dysmenorrhoea, nonmenstrual pelvic pain (NMPP), uterine bleeding and lumbar spine bone mineral density (BMD). RESULTS: Linzagolix pharmacokinetics were described by a 2-compartment model with sequential zero/first-order absorption process (CL/F: 0.422 L/h). E2 changes over time were well described as a function of linzagolix 24-hour AUC (AUC50 : 1.68 × 105 ng h/mL). For a Caucasian reference patient, a change in E2 from 50-20 pg/mL at 24 weeks increased the odds of relief of dysmenorrhoea 1.33-fold and NMPP 1.07-fold (95% CI: 1.22-1.47 and 1.02-1.12, respectively) and decreased bleeding days by 1.55 (95% CI: 1.39-1.72). A previously validated quantitative systems pharmacology BMD model was adjusted to the clinical data. The mean week 24 lumbar spine BMD change from baseline ranged from -0.092% in the 50 mg dose, -1.30% in the 100 mg dose group and -2.67% in the 200 mg dose group. DISCUSSION: The previously-reported E2 target range (20-50 pg/mL) to balance efficacy and safety endpoints was confirmed. Linzagolix once daily doses between 75-125 mg daily were expected to meet endometriosis-associated pain, efficacy, and BMD loss targets in Caucasian patients.

The mechanism of action of oxytocin antagonist nolasiban in ART in healthy female volunteers.

RESEARCH QUESTION: What are the effects of the oxytocin receptor (OTR) antagonist nolasiban on uterine contractions, endometrial perfusion and endometrial mRNA expression? DESIGN: Randomized, double-blind, parallel-group, mechanism-of-action study with nolasiban. Forty-five healthy, pre-menopausal women were treated with placebo, 900 mg or 1800 mg nolasiban on the day corresponding to blastocyst transfer. Ultrasonographic uterine contraction frequency and endometrial perfusion were assessed, and endometrial biopsies analysed by next-generation sequencing. RESULTS: Both doses of nolasiban showed decreased contraction frequency and increased endometrial perfusion depending on the time point assessed. At 1800 mg, 10 endometrial genes (DPP4, CNTNAP3, CNTN4, CXCL12, TNXB, CTSE, OLFM4, KRT5, KRT6A, IDO2) were significantly differentially expressed (adjusted P < 0.05). Of these, OLFM4, DPP4 and CXCL12 were regulated in the same direction as genes involved in implantation during the window of implantation. In addition, three genes (DPP4, CXCL12 and IDO2) were associated with decidualization and endometrial receptivity. CONCLUSIONS: These data expand our knowledge of the mechanism of action of nolasiban in increasing pregnancy rates after embryo transfer. The results suggest more marked effects of nolasiban 1800 mg compared with the 900 mg dose, supporting testing at higher doses in IVF patients.

Confirmation of the cardiac safety of nolasiban in a randomised cohort of healthy female volunteers.

Nolasiban is an orally active oxytocin receptor antagonist being developed to increase the efficiency of assisted reproductive technologies. This study evaluated the pharmacokinetics, pharmacodynamics, and cardiac safety of nolasiban in 45 healthy women of child-bearing age. Nolasiban was administered in a fasted state with a standardised lunch served 4.5 h post-dose. Concentration-effect modelling was used to assess the effect of two dosages of nolasiban (900 mg and 1800 mg) on QTc following single-dose administration. We found no significant change in QTc at all tested dosages. Two-sided 90% confidence intervals of geometric mean Cmax for estimated QTc effects of nolasiban were below the threshold of regulatory concern. The sensitivity of the assay to detect small changes in QTc was confirmed by a significant shortening of QTc between 2 and 4 h after consumption of a meal, which served to validate the model. Independent of the nolasiban assessment, this study also explored the effects of sex hormones on ECG parameters, especially QT subintervals. We found a significant relationship between JTpc and oestradiol. Heart rate was negatively correlated with progesterone. This study confirms the cardiovascular safety of nolasiban and describes relationships of sex hormones and ECG parameters.

Treatment of endometriosis-associated pain with linzagolix, an oral gonadotropin-releasing hormone-antagonist: a randomized clinical trial.

OBJECTIVE: To study the effect of a new investigational oral gonadotropin-releasing hormone antagonist, linzagolix, on endometriosis-associated pain (EAP). DESIGN: A multinational, parallel group, randomized, placebo-controlled, double-blind, dose-ranging trial. SETTING: Clinical centers. PATIENT(S): Women aged 18-45 years with surgically confirmed endometriosis and moderate-to-severe EAP. INTERVENTION(S): The interventions were 50, 75, 100, or 200 mg linzagolix (or matching placebo) administered once daily for 24 weeks. MAIN OUTCOME MEASURE(S): The primary endpoint was the number of responders (≥30% reduction in overall pelvic pain) after 12 weeks. Other endpoints included dysmenorrhea, non-menstrual pelvic pain, serum estradiol, amenorrhea, quality of life (QoL) measures, and bone mineral density (BMD). RESULT(S): Compared with placebo, doses ≥ 75 mg resulted in a significantly greater proportion of responders for overall pelvic pain at 12 weeks (34.5%, 61.5%, 56.4%, and 56.3% for placebo, 75, 100, and 200 mg, respectively). A similar pattern was seen for dysmenorrhea and non-menstrual pelvic pain. The effects were maintained or increased at 24 weeks. Serum estradiol was suppressed, QoL improved, and the rate of amenorrhea increased in a dose-dependent fashion. Mean BMD loss (spine) at 24 weeks was <1% at doses of 50 and 75 mg and increased in a dose-dependent fashion up to 2.6% for 200 mg. BMD of femoral neck and total hip showed a similar pattern. CONCLUSION(S): Linzagolix significantly reduced EAP and improved QoL at doses of 75-200 mg and decreased BMD dose-dependently. CLINICAL TRIAL REGISTRATION NUMBER: NCT02778399.

Effects of combined GnRH receptor antagonist linzagolix and hormonal add-back therapy on vaginal bleeding-delayed add-back onset does not improve bleeding pattern.

Linzagolix is a novel, oral GnRH receptor antagonist developed for the treatment of endometriosis and uterine fibroids. We assessed high-dose linzagolix safety and bleeding pattern effects in healthy women using combined versus delayed hormonal add-back therapy (ABT). This was a single-center, open-label, parallel-group study in 32 premenopausal women, who were randomized to daily linzagolix (200 mg)/ABT for 10 weeks ("Combined-ABT") or linzagolix (200 mg) for 4 weeks followed by linzagolix (200 mg)/ABT for 6 weeks ("Delayed-ABT"). Main outcome measures included bleeding records, trough estradiol (E2) concentrations and adverse events. Linzagolix alone promptly reduced bleeding, leading to amenorrhea in all women by week 5. When combined ABT was started (week 5), spotting (≤ 0.80 days/week/subject) and bleeding (≤ 0.53 days/week/subject) occurred; bleeding was markedly more frequent than after ABT start in the "Combined-ABT" group. In the "Combined-ABT" group, spotting (≤ 0.69 days/week/subject) and occasional bleeding (≤ 0.25 days/week/subject) occurred during the first half of treatment with a tendency to further decrease during the second half. Linzagolix alone rapidly reduced E2 reaching median week 4 levels of 4.1 pg/mL. Median E2 after combined linzagolix/ABT ranged between 35 and 42 pg/mL for the "Delayed-ABT" group (weeks 5-10) and between 24 and 32 pg/mL for the "Combined-ABT" group (weeks 1-10). Linzagolix was well tolerated. Most frequently reported adverse events were headache (32/156) and hot flushes (19/156). Hot flushes exclusively occurred in the "Delayed-ABT" group. In this study, treatment start with a combined linzagolix/ABT regimen resulted in better bleeding control, no hot flushes, and lower median E2 levels than a "Delayed-ABT" regimen. These results may help defining the linzagolix/ABT regimen to be adopted when treating sex-hormone-dependent diseases. Clinical Trial Registration Number-EudraCT Number: 2017-003822-34.

Efficient Design of Integrated and Adaptively Interlinked Protocols for Early-Phase Drug Development Programs.

BACKGROUND: Adaptive trial designs have the potential to address common challenges in drug development; they decrease timelines and costs of early drug development and efficiently create data that support future trials in target populations. While allowing for flexibility and evolution, adaptive strategies introduce some complexity to the design and implementation of trial protocols. Previously published work by the authors include a retrospective analysis of time savings using adaptive design and a systematic, 3- step methodology for writing early-phase adaptive integrated protocols. METHODS: This article builds on the authors' published work demonstrating the practical implementation of the adaptive protocol writing methodology and discussing the challenges and efficiencies. It describes the integration of an early development program of OBE022, a novel, oral, selective prostaglandin F2a receptor antagonist, intended as a treatment for preterm labor, using 2 interdependent, adaptive trial protocols. The program consisted of first-in-human single and multiple ascending dose parts with assessments of food effect, cardiac safety, proof of concept, and interactions of OBE022 with 4 standard of care medicines. RESULTS: The manuscript shows how the trials were tailored to OBE022's pharmacokinetic and pharmacodynamic characteristics and its therapeutic indication. The use of 2 large interdependent, adaptive protocols was facilitated by the United Kingdom's (UK's) regulatory environment and its acceptance of a rules-guided progression through the program. Changes to the planned trial conduct could be made without impacting on timelines, because they used predefined adaptive options within their authorized boundaries, and could therefore be made as nonsubstantial amendments. The program was successful and achieved its objectives. It was efficient and fast: it required a small number of participants (n=83) and completed from start of protocol writing to first draft of the clinical study report in just 11 months. CONCLUSIONS: This program included all key elements of early drug development in 2 interlinked protocols: the assessment of single and multiple ascending doses, food effect, cardiac safety and proof of concept. The approach described in this article demonstrates how early-phase programs can be designed to be performed, analyzed and reported time- and cost-efficiently.

Oxytocin Receptor Antagonists, Atosiban and Nolasiban, Inhibit Prostaglandin F2α-induced Contractions and Inflammatory Responses in Human Myometrium.

Oxytocin receptor antagonists (OTR-A) have been developed as tocolytics for the management of preterm labour due to the significant role of oxytocin (OT) in the onset of both term and preterm labour. Similar to OT, prostaglandins (PGs) play key roles in myometrial contractility and cervical ripening. Inhibition of PG synthesis/activity is used to delay preterm birth. Thus, targeting the PG pathway in combination with an OTR-A may be an effective strategy for delaying preterm delivery. In this study, we examined the effects of atosiban and nolasiban on PGF2α-induced contractions and pro-inflammatory responses in human pregnant myometrium. Both OTR-As, atosiban and nolasiban, inhibited PGF2α-induced contractions in a dose-dependent manner (p < 0.001 and p < 0.01, respectively). These inhibitory effects involved the suppression of PGF2α-mediated increase in intracellular calcium levels. In addition, the OTR-As significantly suppressed PGF2α-induced activation of pro-inflammatory pathways such as NF-κB and mitogen activated protein kinases (MAPKs), and the subsequent expression of contraction-associated-protein, COX-2. We have demonstrated that atosiban and nolasiban not only inhibit contractions elicited by OT, but also inhibit contractions and inflammation induced by PGF2α. This suggests a possible crosstalk between OTR and PG receptor signalling and highlights the importance of understanding G protein-coupled receptor interactions/crosstalk in the development of future tocolytics.

Coadministration of the prostaglandin F2α receptor antagonist preterm labour drug candidate OBE022 with magnesium sulfate, atosiban, nifedipine and betamethasone.

AIMS: To investigate presence or absence of clinically relevant drug interactions (pharmacokinetic and safety/tolerability) of OBE022 with standard-of-care medicines for preterm labour, enabling coadministration and further clinical development. METHODS: Part A: open-label, randomized, 3-period crossover assessing coadministration of single doses of OBE022 (1100 mg) and MgSO4 . Part B: open-label, single-sequence crossover assessing the interactions following administration of OBE022 (1000 mg/day) at steady state coadministered with single doses of atosiban, nifedipine and betamethasone. Twenty-five healthy nonpregnant women of reproductive age were enrolled (Part A: n = 12; Part B: n = 13). RESULTS: OBE022, alone or in combination with standard-of-care medications, was well tolerated. Headache and dizziness were the most frequently reported adverse events; dizziness occurred more often with the nifedipine/OBE022 combination. There were no clinically significant pharmacokinetic interactions when coadministered with MgSO4 . Co-administration had no notable effect on atosiban exposure. Atosiban reduced exposure to OBE002 (peak concentration [Cmax ] 22%, area under the concentration-time curve [AUC] 19%). Coadministration with betamethasone slightly increased betamethasone exposure (Cmax  + 18%, AUC +27%) and OBE002 exposure (Cmax  + 35%, AUC +15%). These changes were not considered clinically significant. Coadministration with nifedipine slightly increased OBE002 exposure (Cmax  + 29%, AUC +24%) and markedly increased nifedipine exposure (Cmax by 2-fold and AUC by 2-fold), which may be clinically significant. CONCLUSIONS: The use of OBE022, a PGF2α antagonist prodrug, in combination with standard-of-care medicines may provide new treatment alternatives for preterm labour. All tested combinations were well tolerated. Nifedipine doses could potentially be reduced or staggered when coadministered with OBE022.

Treatment of female rhesus macaques with a somatostatin receptor antagonist that increases oocyte fertilization rates without affecting post-fertilization development outcomes.

PURPOSE: To determine the effects of PGL1001, a somatostatin receptor isoform-2 (SSTR-2) antagonist, on ovarian follicle development, oocyte fertilization, and subsequent embryo developmental potential in the rhesus macaque. METHODS: Cycling female rhesus macaques (N = 8) received vehicle through one menstrual (control) cycle, followed by daily injections of PGL1001, a SSTR-2 antagonist, for three menstrual (treatment) cycles. Main endpoints include overall animal health and ovarian hormones (e.g., estradiol [E2], progesterone [P4], and anti-Müllerian hormone [AMH]), ovarian circumference, numbers of oocytes and their maturation status following controlled ovarian stimulation (COS), as well as oocyte fertilization and subsequent blastocyst rates that were assessed in control and PGL1001 treatment cycles. Circulating PGL1001 levels were assessed at baseline as well as 6, 60, and 90 days during treatment. RESULTS: PGL1001 treatment did not impact overall animal health, menstrual cycle length, or circulating levels of ovarian hormones (E2, P4, and AMH) in comparison to vehicle treatment during natural cycles. PGL1001 treatment increased (p Ë‚ 0.05) ovarian circumference and the day 8 to day 1 ratio of AMH levels (p Ë‚ 0.05) during a COS protocol, as well as oocyte fertilization rates compared to the vehicle treatment interval. Blastocyst development rates were not significantly different between vehicle and PGL1001 treatment groups. CONCLUSION: Prolonged treatment with PGL1001 appears to be safe and does not affect rhesus macaque general health, menstrual cycle length, or ovarian hormone production. Interestingly, PGL1001 treatment increased the fertilization rate of rhesus macaque oocytes collected following ovarian stimulation.

OBE022, an Oral and Selective Prostaglandin F2α Receptor Antagonist as an Effective and Safe Modality for the Treatment of Preterm Labor.

Preterm birth is the major challenge in obstetrics, affecting ∼10% of pregnancies. Pan-prostaglandin synthesis inhibitors [nonsteroidal anti-inflammatory drugs (NSAIDs)] prevent preterm labor and prolong pregnancy but raise concerns about fetal renal and cardiovascular safety. We conducted preclinical studies examining the tocolytic effect and fetal safety of the oral prodrug candidate OBE022 [(S)-2-amino-3-methyl-butyric acid (S)-3-{[(S)-3-(biphenyl-4-sulfonyl)-thiazolidine-2-carbonyl]-amino}-3-(4-fluoro-phenyl)-propyl ester] and its parent OBE002 [(S)-3-(biphenyl-4-sulfonyl)-thiazolidine-2-carboxylic acid [(S)-1-(4-fluoro-phenyl)-3-hydroxy-propyl]-amide], both potent and highly selective antagonist of the contractile prostaglandin F2α (PGF2α ) receptor (FP). Efficacy of OBE022 and OBE002, alone and in combination with other tocolytics, was assessed in human tissues and pregnant animal models for inhibition of uterine contraction and delay of parturition. Selective safety of OBE022 and/or OBE002, compared with NSAID indomethacin, was assessed on renal function, closure of the ductus arteriosus, and inhibition of platelet aggregation. In in vitro studies, OBE002 inhibited spontaneous, oxytocin- and PGF2α -induced human myometrial contractions alone and was more effective in combination with atosiban or nifedipine. In in vivo studies, OBE022 and OBE002 reduced spontaneous contractions in near-term pregnant rats. In pregnant mice, OBE022 delayed RU486 [(8S,11R,13S,14S,17S)-11-[4-(dimethylamino)phenyl]-17-hydroxy-13-methyl-17-prop-1-ynyl-1,2,6,7,8,11,12,14,15,16-decahydrocyclopenta[a]phenanthren-3-one] -induced parturition and exerted synergistic effects in combination with nifedipine. OBE022 and/or OBE002 did not show the fetal side effects of ductus arteriosus constriction, impairment of kidney function, or inhibition of platelet aggregation observed with indomethacin. Orally active OBE022 and OBE002 exhibits potent tocolytic effects on human tissues ex vivo and animal models in vivo without causing the adverse fetal side effects seen with indomethacin. Selectively targeting the FP receptor in combination with existing tocolytics may be an effective strategy for preventing or delaying preterm delivery.

Pharmacokinetics, safety and tolerability of OBE022, a selective prostaglandin F2α receptor antagonist tocolytic: A first-in-human trial in healthy postmenopausal women.

AIMS: Preterm birth remains a significant risk for later disability. The selective inhibition of the prostaglandin F2α receptor has significant advantages for a tocolytic. The prodrug OBE022 and its metabolite OBE002 are novel prostaglandin F2α receptor antagonists under development for treating preterm labour. METHODS: We performed a prospective, first in human, Phase I, dose escalation, placebo-controlled, randomized trial at a clinical trial site in the UK. Placebo, single ascending doses of 10, 30, 100, 300, 1000 or 1300 mg, and multiple ascending doses over 7 days of 100, 300 or 1000 mg day-1 ; were administered to postmenopausal female volunteers. Food interaction was additionally evaluated. RESULTS: Subjects tolerated OBE022 well at all single and multiple doses. No clinically relevant changes in safety parameters were shown and there were no serious adverse events. Observations showed that prodrug OBE022 was readily absorbed and rapidly converted into its equally active stable metabolite OBE002. The plasma level of OBE002 rose with increasing doses, reaching exposure levels that were anticipated to be clinically relevant within 1 h following administration. There was no clinically significant food interaction, with peak exposures reduced to 80% and area under the curve staying bioequivalent. The mean half-life of OBE002 ranged between 8 and 11 h following administration of a single dose and 22-29 h after multiple doses. CONCLUSIONS: Administration of OBE022 was safe and had favourable pharmacokinetic characteristics and no clinically relevant interaction with food. Our results allow further investigation of OBE022 in preterm labour patients.

Confirmation of the Cardiac Safety of PGF2α Receptor Antagonist OBE022 in a First-in-Human Study in Healthy Subjects, Using Intensive ECG Assessments.

OBE022, a new orally active prostaglandin F2α  receptor antagonist (OBE022) with myometrial selectivity is being developed to reduce uterine contractions during preterm labor. This first-in-human study evaluated the effect of OBE022 following multiple doses on the QT interval in 23 healthy postmenopausal women, using the effect of a meal on QTc to demonstrate assay sensitivity. We report the cardiac safety outcome performed during the multiple ascending part of this trial. OBE022 was administered after a standardized breakfast on day 1 and in the fasted state from day 3 to day 9 wth a standardized lunch 4 hours after administration. Concentration-effect modeling was used to assess the effect of prodrug OBE022 and parent OBE002 on QTc after a single dose (days 1 and 3) and multiple doses (day 9). The concentration-response analysis showed the absence of QTc prolongation at all doses tested. Two-sided 90% confidence intervals of the geometric mean Cmax  for estimated QTc effects of OBE022 and OBE002 of all dose groups were consistently below the threshold of regulatory concern. The sensitivity of this study to detect small changes in the QTc was confirmed by a significant shortening of the QTc on days 1, 3, and 9 after standardized meals. This study establishes that neither prodrug OBE022 nor parent OBE002 prolong the QTc interval. The observed food effect on the QT interval validated the assay on all assessment days. Both the change from predose, premeal and the change from premeal, postdose demonstrated the specificity of the method.

Gonadotropin-Releasing Hormone Receptor Antagonist Mono- and Combination Therapy With Estradiol/Norethindrone Acetate Add-Back: Pharmacodynamics and Safety of OBE2109.

Context: OBE2109 is a potent, oral gonadotropin-releasing hormone receptor antagonist being developed for the treatment of sex-hormone-dependent diseases in women. Objective: We assessed the pharmacodynamics and safety of OBE2109 alone and combined with estradiol (E2)/norethindrone acetate (NETA) add-back therapy on E2 levels and vaginal bleeding. Design, Setting, and Participants: This was a single-center, open-label, randomized, parallel-group study in 76 healthy premenopausal women. Interventions: Women were randomly assigned to take the following doses (in milligrams) once daily for 6 weeks: OBE2109, 100 or 200; or OBE2109/E2/NETA, 100/0.5/0.1, or 100/1.0/0.5, or 200/1.0/0.5. Main Outcome Measures: E2 concentrations, bleeding pattern, exploratory bone metabolism biomarkers, and adverse events. Results: OBE2109 100 mg and 200 mg alone reduced E2 levels to reach median levels of 19.5 and 3.2 pg/mL, respectively, at week 4. Median E2 levels after combined OBE2109/add-back therapy ranged between 25 and 40 pg/mL. OBE2109 100 mg or 200 mg alone induced amenorrhea. By day 15, >85% of women had no vaginal bleeding during the last 4 weeks of treatment. Add-back therapy partially impaired bleeding control: The highest amenorrhea rate (53%) was observed with OBE2109 100 mg/1.0 mg/0.5 mg. The addition of E2/NETA, particularly at 1 mg/0.5 mg, mitigated the increase of two bone markers induced by OBE2109 200 mg. Conclusion: OBE2109 promptly lowered E2 levels. Add-back therapy may be required to prevent adverse effects on bone in women treated with the 200-mg dose (at 100 mg in some women). These results provide a basis for OBE2109 regimen selection to treat sex-hormone-dependent diseases.

Differential Effects of Oxytocin Receptor Antagonists, Atosiban and Nolasiban, on Oxytocin Receptor-Mediated Signaling in Human Amnion and Myometrium.

One of the most established roles of oxytocin (OT) is in inducing uterine contractions and labor. Apart from inducing contractions, our recent studies showed that OT can also activate proinflammatory pathways in both human myometrial and amnion cells, which suggests that the proinflammatory role of OT should be taken into account when developing tocolytics targeting the OT/oxytocin receptor (OTR) system. The OTR antagonist, atosiban, is currently used therapeutically for the treatment of preterm labor. We previously showed that atosiban fails to inhibit the proinflammatory effects of OT in human amnion; atosiban alone activates nuclear factor-κB (NF-κB) and mitogen activated protein kinases, thus upregulating downstream prolabor genes. In contrast with our findings with atosiban, the presence of the orally active OTR antagonist, nolasiban, reduced the effect of OT on NF-κB and p38 kinase activation in both myometrial and amnion cells. Consistent with the activation of these inflammatory mediators, OT led to increases in the expression of cyclooxygenase-2 and phosphorylated cytosolic phospholipase A2, which was reflected in prostaglandin E2 synthesis. Inhibition of NF-κB activation by nolasiban also translated to suppression of downstream prolabor gene expression, such as cyclooxygenase-2, C-C motif chemokine ligand 2, interleukin-6, and interleukin-8. We also demonstrated that nolasiban treatment alone has no significant stimulatory effect on both the myometrium and amnion. In conclusion, our findings indicate that nolasiban possesses promising potential as a novel tocolytic agent for both acute and maintenance therapy, as it inhibits both myometrial contractions and the proinflammatory effects of OT without the biased agonist effects.

Bentamapimod (JNK Inhibitor AS602801) Induces Regression of Endometriotic Lesions in Animal Models.

Endometriosis is an estrogen (ER)-dependent gynecological disease caused by the growth of endometrial tissue at extrauterine sites. Current endocrine therapies address the estrogenic aspect of disease and offer some relief from pain but are associated with significant side effects. Immune dysfunction is also widely believed to be an underlying contributor to the pathogenesis of this disease. This study evaluated an inhibitor of c-Jun N-terminal kinase, bentamapimod (AS602801), which interrupts immune pathways, in 2 rodent endometriosis models. Treatment of nude mice bearing xenografts biopsied from women with endometriosis (BWE) with 30 mg/kg AS602801 caused 29% regression of lesion. Medroxyprogesterone acetate (MPA) or progesterone (PR) alone did not cause regression of BWE lesions, but combining 10 mg/kg AS602801 with MPA caused 38% lesion regression. In human endometrial organ cultures (from healthy women), treatment with AS602801 or MPA reduced matrix metalloproteinase-3 (MMP-3) release into culture medium. In organ cultures established with BWE, PR or MPA failed to inhibit MMP-3 secretion, whereas AS602801 alone or MPA + AS602801 suppressed MMP-3 production. In an autologous rat endometriosis model, AS602801 caused 48% regression of lesions compared to GnRH antagonist Antide (84%). AS602801 reduced inflammatory cytokines in endometriotic lesions, while levels of cytokines in ipsilateral horns were unaffected. Furthermore, AS602801 enhanced natural killer cell activity, without apparent negative effects on uterus. These results indicate that bentamapimod induced regression of endometriotic lesions in endometriosis rodent animal models without suppressing ER action. c-Jun N-terminal kinase inhibition mediated a comprehensive reduction in cytokine secretion and moreover was able to overcome PR resistance.

c-Jun NH2-terminal kinase inhibitor bentamapimod reduces induced endometriosis in baboons: an assessor-blind placebo-controlled randomized study.

OBJECTIVE: To test the hypothesis that the c-Jun NH2-terminal kinase (JNK) inhibitor (JNKI) bentamapimod (AS602801/PGL5001) can reduce induced endometriosis in baboons. DESIGN: Prospective randomized placebo-controlled study. SETTING: Nonhuman primate research center. ANIMAL(S): Twenty baboons each underwent four laparoscopies. Initial screening laparoscopy (L1) was followed after one rest cycle by an endometriosis-induction laparoscopy (L2). Fifty days after L2, the baboons were randomized just before staging laparoscopy (L3). Treatment lasted for 60 days, followed by a post-treatment staging laparoscopy (L4). INTERVENTION(S): Randomization before a 60-day treatment in four groups: daily placebo (n = 5), daily oral administration of 20 mg/kg JNKI (n = 5), concomitant daily oral administration of 20 mg/kg JNKI and 10 mg medroxyprogesterone acetate (MPA; n = 5), or subcutaneous administration of 3 mg cetrorelix every 3 days (n = 5). MAIN OUTCOME MEASURE(S): Type, surface area and volume of endometriotic lesions, and revised American Society for Reproductive Medicine score and stage were recorded during L3 and L4. Menstrual cycle length and serum hormonal concentration were recorded before and after treatment. RESULT(S): Compared with placebo, treatment with JNKI, JNKI + PMA, or cetrorelix resulted in lower total surface area and volume of endometriotic lesions. Remodeling of red active lesions into white lesions was observed more frequently in baboons treated with JNKI + MPA than in baboons treated with JNKI only. Menstrual cycle length and serum hormonal concentration were similar between placebo and JNKI groups. CONCLUSION(S): JNKI alone was as effective as JNKI + MPA or cetrorelix in reducing induced endometriosis in baboons, but without severe side effects or effect on cycle length or serum reproductive hormones.

The clinical pharmacology and pharmacokinetics of ulipristal acetate for the treatment of uterine fibroids.

Uterine fibroids are benign hormone-sensitive tumors of uterine smooth muscle cells leading to heavy menstrual bleeding and pelvic pain. Ulipristal acetate (UPA) is an emerging medical treatment of fibroids with the potential to be used for long-term treatment. In this context, the present article summarizes UPA's main clinical pharmacology and pharmacokinetic (PK) properties. Ulipristal acetate has good oral bioavailability and a half-life allowing one single oral administration per day for the management of fibroids. As a steroid, UPA is a substrate for cytochrome P450 (CYP) 3A4 but does not act as an inducer or inhibitor of the CYP system or transporter proteins. With the exception of drugs modulating CYP3A4 activity, risks of drug-drug interactions with UPA are unlikely. In conclusion, besides its pharmacodynamic characteristics, UPA shows favorable PK properties that contribute to a good efficacy-safety ratio for the long-term management of uterine fibroids in clinical practice.

Synergistic effects of E2MATE and norethindrone acetate on steroid sulfatase inhibition: a randomized phase I proof-of-principle clinical study in women of reproductive age.

The combination of a progestin such as norethindrone acetate (NETA) reducing the ovarian estrogen production with a steroid sulfatase (STS) inhibitor (STS-I) decreasing the local estrogen production could result in a new treatment option for endometriosis. The study reported was a randomized, double-blind, and placebo-controlled study to investigate the pharmacodynamics, pharmacokinetics, and safety of the STS-I PGL2001 (E2MATE) and NETA. A total of 24 healthy women of reproductive age were treated with weekly doses of PGL2001 or daily doses of NETA or a combination of both compounds for 4 weeks. Four weeks of treatment with PGL2001 or PGL2001 + NETA reduced the STS activity in the endometrium by 91% (±3%) and 96% (±4%), respectively, and comparable values were observed 1 month after the treatment was stopped. The combined treatment of PGL2001 + NETA led to significantly higher STS inhibition at both times (P < .01 and P < .05, respectively). This study showed that administration of PGL2001 alone at 4 mg/week or combined with NETA to healthy women of reproductive age led to STS inhibition and changes in functional STS biomarkers in the endometrium, resulting in synergistic effects of PGL2001 and NETA on STS activity.

Carcinogenicity and chronic rodent toxicity of the selective progesterone receptor modulator ulipristal acetate.

Carcinogenic properties of ulipristal acetate (UPA), a selective progesterone receptor modulator developed for the treatment of benign gynecological conditions such as uterine fibroids, were assessed in a 26-week carcinogenicity study in transgenic TgRasH2 mice and a 104-week study in Sprague Dawley rats. Dose levels used in the mouse study were 15, 45, or 130 mg/kg/day and for the ratstudy the doses used were 1, 3, or 10 mg/kg/day. Vehicle and water controls were part of both studies and a positive control, N-Nitroso-N-methylurea intraperitoneally, was included in the transgenic mouse assay. Survival at all dose levels was similar to vehicle controls in both sexes of both species and there was no evidence of any UPA-induced carcinogenicity in either species. Rats receiving UPA had decreased incidences of fibroadenomas and adenocarcinomas in the mammary gland in all treated groups. UPA exposure [AUC(0-24h)] at the highest dose in rats was 67 times human therapeutic exposure at 10 mg/day. In mice, no tumor of any type increased at UPA exposures up to 313 times of therapeutic exposure. UPA-related findings in mice were limited to organ weight changes in the liver, pituitary, thyroid/parathyroid glands, and epididymis as well as minimal panlobular hepatocellular hypertrophy in male and female mice receiving 130 mg/kg/day. Rats had UPA-related non-neoplastic findings in the reproductive system (mammary gland, ovary, uterus, vagina, seminal vesicle, prostate), endocrine system (adrenal, pituitary), thymus, muscle, liver, pancreas and lungs most of which are considered to be due to exaggerated pharmacological action of the compound.