Trial Outcomes & Findings for A Study to Investigate Efficacy and Safety of OG-6219 BID in 3 Dose Levels Compared With Placebo in Participants Aged 18 to 49 With Moderate to Severe Endometriosis-related Pain (NCT NCT05560646)

This Phase 2a/b, double-blind, placebo-controlled study was conducted in pre-menopausal women 18 to 49 years of age with moderate to severe endometriosis-related pain (ERP) at 93 centers in 11 countries between 25 October 2022 and 28 May 2025.

A total of 354 participants were randomized and enrolled in the study. Participants were randomized in a 1:1:1:1 ratio at randomization visit (Visit 4) to receive 1 of 3 doses of OG-6219 or matching placebo.

Modified full analysis set included all randomized participants who received at least 1 dose of study drug and who completed at least 1 subsequent diary entry for dysmenorrhea or NMPP.

Participants completed eDiary items for severity of their pain over the last 24 hours on 11-point NRS for dysmenorrhea or NMPP, and dyspareunia. Each item of the NRS pain severity score ranged from 0 (no pain) to 10 (worst pain imaginable), where lower score indicated a better outcome. The mean OPP score was derived by the pain score for the dysmenorrhea and NMPP items, and score ranged from 0 (no pain) to 10 (worst pain imaginable), where lower score indicated a better outcome. Baseline cycle OPP score was defined as the average daily OPP during baseline cycle.

An adverse event (AE) was defined as any untoward medical occurrence in a clinical study participant administered an investigational product and which does not necessarily have a causal relationship with this treatment. An SAE was defined as any AE that at any dose resulted in death, was life-threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, was a congenital anomaly/birth defect, or was an important medical event. TEAEs were defined as events that first occur or worsen (increase in severity) after the first dose of study drug, during the treatment period, and up to 14 days (inclusive) after the last dose of study drug administration. Percentages are rounded off to the hundredth decimal place.

An AE was defined as any untoward medical occurrence in a clinical study participant administered an investigational product and which does not necessarily have a causal relationship with this treatment. TEAEs were defined as events that first occur or worsen (increase in severity) after the first dose of study drug, during the treatment period, and up to 14 days (inclusive) after the last dose of study drug administration. The TEAEs leading to permanent discontinuation of study drug was identified by using the 'Action taken with study treatment' variable equal to 'Drug withdrawal' from the AE page of the electronic case report form. Percentages are rounded off to the hundredth decimal place.

Participants completed eDiary items for severity of their pain over the last 24 hours on 11-point NRS for dysmenorrhea. Each item of the NRS pain severity score ranged from 0 (no pain) to 10 (worst pain imaginable), where lower score indicated a better outcome. The mean dysmenorrhea score was calculated for each cycle as the total of daily dysmenorrhea scores reported during the cycle divided by the number of days during the cycle when a dysmenorrhea score was reported. Baseline cycle started at the start of menses associated with Visit 3 and ended at the day before the start of menses associated with Visit 4, or the day of Visit 4, whichever comes first.

Participants completed eDiary items for severity of their pain over the last 24 hours on 11-point NRS for dysmenorrhea. Each item of the NRS pain severity score ranged from 0 (no pain) to 10 (worst pain imaginable), where lower score indicated a better outcome. The mean NMPP score was calculated for each cycle as the total of daily NMPP scores reported during the cycle divided by the number of days during the cycle when a NMPP score was reported. Baseline cycle started at the start of menses associated with Visit 3 and ended at the day before the start of menses associated with Visit 4, or the day of Visit 4, whichever comes first.

Participants completed eDiary items for severity of their pain over the last 24 hours on 11-point NRS for dyspareunia. Each item of the NRS pain severity score ranged from 0 (no pain) to 10 (worst pain imaginable), where lower score indicated a better outcome. The mean dyspareunia score was calculated for each cycle as the total of dyspareunia scores reported during each cycle divided by the number of days when participants engaged in any sexual activity that involved full vaginal penetration during each cycle (that is, the number of days during the baseline cycle when a dyspareunia score was reported). Baseline cycle started at the start of menses associated with Visit 3 and ended at the day before the start of menses associated with Visit 4, or the day of Visit 4, whichever comes first.

Participants were asked daily whether they used the rescue medication in the past 24 hours to treat their ERP. If yes, the number of tablets was documented. The mean number of tablets of rescue medication for ERP was calculated for each cycle as the total number of tablets of rescue medication for ERP reported during the cycle, divided by the number of days during the cycle when a value was reported. Baseline cycle started at the start of menses associated with Visit 3 and ended at the day before the start of menses associated with Visit 4, or the day of Visit 4, whichever comes first.

Participants were asked daily whether they used the rescue medication in the past 24 hours to treat their ERP. If yes, the number of tablets was documented. The percentage of days participant had used rescue medication for ERP was calculated for each cycle as the total number of days participant had used any rescue medication for ERP, divided by the number of days during the cycle when a value was reported. Baseline cycle started at the start of menses associated with Visit 3 and ended at the day before the start of menses associated with Visit 4, or the day of Visit 4, whichever comes first.

The PGI-S was a single item measuring the overall severity of pelvic pain over the past 7 days on a 4-point Likert-type scale (0=None, 1=Mild, 2=Moderate, 3=Severe), score ranged from 0 (none) and 3 (severe), where lower score indicated a better outcome. Treatment Cycle 1 was the period between the first day of menses associated with treatment start (Visit 4) to the day prior to the first day of next menses, regardless of number of days.

The PGI-C was a single item measuring the change in pelvic pain since the start of the study drug on a 5-point scale (0=much better, 1=a little better, 2=no change, 3=a little worse, 4=much worse), score ranged from 0 (much better) and 4 (much worse), where lower score indicated a better outcome. Participants with any improvement on the PGI-C were defined as a PGI-C score of 0 or 1 (0=much better and 1=a little better). Treatment Cycle 2 was the period between the first day of menses associated with start of treatment Cycle 2 to the day prior to the first day of next menses, regardless of number of days.

The EHP-30 was a validated disease specific patient-reported outcome instrument measuring the health-related quality of life of women with endometriosis on a 5-point Likert-type scale (0=never, 1=rarely, 2=sometimes, 3=often, 4=always). The EHP-30 consisted of 30 items with following domains: pain (11 items), score ranged from 0 (never) to 44 (always); controls and powerlessness (6 items), score ranged from 0 (never) to 24 (always); emotional well-being (6 items), score ranged from 0 (never) to 24 (always); social support (4 items), score ranged from 0 (never) to 16 (always); and self-image (3 items), score ranged from 0 (never) to 12 (always). Each domain lower score indicated a better outcome. Total EHP-30 score ranged from 0 (never) and 120 (always), where lower score indicated a better outcome. Baseline cycle started at the start of menses associated with Visit 3 and ended at the day before the start of menses associated with Visit 4, or the day of Visit 4, whichever comes first.

Potential effects on bone was monitored by biomarkers of bone resorption and formation. Bone resorption was determined by assessing CTX level and bone formation was determined by assessing P1NP level. Screening (Visit 1) was defined as the last measurement before study drug administration.

Potential effects on bone was monitored by biomarkers of bone resorption and formation. Bone formation was determined by assessing BSAP and osteocalcin level. Screening (Visit 1) was defined as the last measurement before study drug administration.

Potential effects on bone was monitored by biomarkers of bone resorption and formation. Bone resorption was determined by assessing NTX level. Screening (Visit 1) was defined as the last measurement before study drug administration. nmol BCE/L= nanomoles of bone collagen equivalents per liter.

Potential effects on bone was monitored by biomarkers of bone resorption and formation. Bone resorption was determined by assessing TRAP5b level. Screening (Visit 1) was defined as the last measurement before study drug administration.

Blood samples were collected to determine the clinical laboratory abnormalities. The laboratory assessments included chemistry, hematology and urinalysis.

Participants recorded the presence of bleeding or spotting daily in the eDiary. The daily questions to assess bleeding pattern in the eDiary were "1a: During the past 24 hours, did you have any vaginal bleeding or spotting? If the response is "Yes", then the next question is, "1b: During the past 24 hours, have you been on your period?". Baseline cycle started at the start of menses associated with Visit 3 and ended at the day before the start of menses associated with Visit 4, or the day of Visit 4, whichever comes first.

Triplicate standard 12-lead ECGs was obtained after the participant was in supine position for at least 5 minutes. The ECG measurements was summarized by taking the average of the available assessments. Only clinically significant ECG abnormalities are reported.

Blood samples were collected to determine the serum level of LH and FSH. The LH surge was determined with urine LH kit at home. Screening (Visit 1) was defined as the last measurement before study drug administration.

Blood samples were collected to determine the serum level of E1. The LH surge was determined with urine LH kit at home. Screening (Visit 1) was defined as the last measurement before study drug administration.

Blood samples were collected to determine the serum level of progesterone, testosterone and DHEA. The LH surge was determined with urine LH kit at home. Screening (Visit 1) was defined as the last measurement before study drug administration.

Blood samples were collected to determine the serum level of free testosterone and E2. The LH surge was determined with urine LH kit at home. Screening (Visit 1) was defined as the last measurement before study drug administration.

Blood samples were collected to determine the serum level of DHEAS. The LH surge was determined with urine LH kit at home. Screening (Visit 1) was defined as the last measurement before study drug administration.

Blood samples were collected to determine plasma concentration of OG-6219 and FOR-1011. The plasma concentration of OG-6219 and FOR-1011 was analyzed using an appropriate validated bioanalytical method.

Blood samples were collected to determine Cmax of OG-6219 and FOR-1011. The Cmax of OG-6219 and FOR-1011 was calculated using non-compartmental method. NCA= Noncompartmental analysis.

Blood samples were collected to determine tmax of OG-6219 and FOR-1011. The tmax of OG-6219 and FOR-1011 was calculated using non-compartmental method.

Blood samples were collected to determine AUCtau of OG-6219 and FOR-1011. The AUCtau of OG-6219 and FOR-1011 was calculated using non-compartmental method.