The effectiveness of RECORLEV in patients with Cushing's syndrome was evaluated in two studies, Study 1 and Study 2.
Study 1
Study 1 consisted of an open-label dose titration and maintenance phase of up to 19 weeks duration, followed by an 8-week double-blind, placebo-controlled, randomized withdrawal phase (NCT03277690).
Study 1 enrolled 84 Cushing’s syndrome patients with persistent or recurrent disease despite surgery, previously medically treated patients, and previously untreated patients. The etiology of Cushing's syndrome was Cushing's disease for 70 (83%) patients, adrenal Cushing’s syndrome in 8 (10%) patients, ectopic ACTH secretion for 2 (2%) patients, and unknown for 4 (5%) patients. Patients with pituitary or adrenal carcinoma were excluded. Twelve (14%) patients who had previously received RECORLEV in Study 2 were also enrolled in Study 1. The mean age at baseline was 45 years; 76% of patients were female. Overall, the mean time since diagnosis was 63 months before treatment with the first dose in this study. Persistence or recurrence of Cushing’s syndrome was evidenced by the mean of three 24-hour UFC levels greater than or equal to 1.5 × upper limit of normal (normal range: 11 to 138 nmol/day or 4 to 50 µg/day). For the 79 patients who underwent dose titration, the mean mUFC (SD) at study baseline was 785 nmol/day (932), which corresponds to approximately 6 × ULN. The median mUFC at baseline was 479 nmol/day, which corresponds to approximately 3.5 × ULN. Seventy-two (72) patients were naïve to treatment with RECORLEV, seven (7) patients were treated with RECORLEV in Study 2 but were not on therapeutic dose (dose at which mUFC level was ≤ ULN, or maximum allowed dose [600 mg twice daily] had been reached, or a clinically meaningful partial response based on clinical judgement, and the maximum tolerated dose had been reached) prior to the enrollment in Study 1. Five (5) of 84 patients continued treatment with therapeutic dose of RECORLEV prior to the enrollment in Study 1; these patients were enrolled directly in the randomized withdrawal phase.
Dose Titration and Maintenance Phase (14-19 weeks)
Seventy-nine (79) patients entered the dose titration and maintenance phase. Patients naïve to treatment with RECORLEV were started on 150 mg of RECORLEV orally twice daily. Patients who previously participated in Study 2 could start on a dose higher than 150 mg twice daily. The dose could be titrated in 150-mg increments at 2-week intervals to a maximum of 600 mg twice daily to achieve mUFC within the normal range. The dose was increased if mUFC was above ULN and was reduced based on individual tolerability. Patients who achieved a stable therapeutic dose for at least 4 weeks and achieved a normal mUFC at the end of the dose titration and maintenance phase were eligible for the randomized withdrawal phase.
Randomized Withdrawal Phase (approximately 8 weeks)
Forty-four (44) patients entered the randomized withdrawal phase: 39 patients from dose titration and maintenance phase and 5 patients directly from Study 2. Patients were randomized in a 1:1 ratio to either continue RECORLEV or receive matched placebo for approximately 2 months or until early rescue was necessary (i.e., for mUFC >1.5 × ULN).
Efficacy Assessment and Results
The key secondary efficacy endpoint was the proportion of patients with mUFC normalization, defined as a patient with mUFC at or below the ULN at the end of randomized withdrawal phase without meeting a requirement for early rescue during the randomized withdrawal phase.
Out of the 79 patients who entered the dose titration and maintenance phase, 37 (47%) patients who met the requirement to be on a stable therapeutic dose for at least 4 weeks and established normal mUFC at the end of the dose titration and maintenance phase, and 2 patients who did not meet the requirement due to abnormal mUFC, continued to the randomized-withdrawal phase. Out of 5 patients from Study 2 who were enrolled directly in the randomized withdrawal phase, 2 patients had normal mUFC.
Among the 39 patients who had normal mUFC at the randomized withdrawal phase baseline, 21 were randomized to the RECORLEV group and 18 to the placebo group. The number and percent of patients who had normal mUFC at the end of the randomized withdrawal phase was 11/21 (52.4%) in RECORLEV group and 1/18 (5.6%) in placebo group, and the treatment difference (CI) was 46.8% (16.5%, 70.2%). Out of 11 patients with normal mUFC at the end of the randomized-withdrawal phase, 7 patients in the RECORLEV group had normal mUFC throughout the randomized-withdrawal phase. Figure 1 depicts the mUFC during the randomized-withdrawal phase of Study 1. The line for the placebo group should be interpreted with caution as majority of placebo patients were rescued early due to high mUFC levels and were not included in the analysis.
Figure 1: Line Plot of the Mean Urinary Free Cortisol During the Randomized Withdrawal Phase of Study 1 - Observed Mean (± SE)
Figure 1 (Figure 1 Recorlev)
mUFC = Mean Urinary Free Cortisol; RW = Randomized Withdrawal; SE = Standard Error; ULN = Upper Limit of Normal
Only patients who remained in study with non-missing mUFC are included in the analysis
Study 2
Supportive evidence of efficacy was obtained from Study 2 which was a multicenter, single-arm, open-label study that consisted of three study phases (dose titration, maintenance, and extended evaluation) for a total estimated treatment duration of up to 73 weeks (NCT01838551).
Study 2 enrolled 94 Cushing’s syndrome patients naïve to the treatment with RECORLEV with persistent or recurrent disease despite surgery, previously medically treated patients, and previously untreated patients. The etiology of Cushing's syndrome was benign pituitary adenoma for 80 (85%) patients, adrenal Cushing’s syndrome in 8 (9%) patients, ectopic ACTH secretion for 1 (1%) patient, and unknown source for 5 (5%) patients. Patients with pituitary or adrenal carcinoma were excluded. The mean age at enrollment was 44 years; 82% of patients were female. Overall, the mean time since diagnosis was 68 months before treatment with the first dose in this study. Persistence or recurrence of Cushing’s syndrome was evidenced by the mean of four 24-hour UFC (mUFC) levels greater than or equal to 1.5 times upper limit of normal (ULN); normal range: 11 to 138 nmol/day or 4 to 50 µg/day). The mean (SD) of the mean urinary free cortisol (mUFC) at baseline was 243 µg/day (269), which corresponds to approximately 5 x ULN. The median mUFC at baseline was 148 µg/day (range 59-1510), which corresponds to approximately 3 x ULN.
Dose Titration Phase (2 to 21 weeks)
Ninety-four (94) patients received a starting dosage of 150 mg RECORLEV orally twice daily that was titrated approximately every 2 to 3 weeks if mUFC was above the ULN to a maximum of 600 mg twice daily. Patients who achieved a therapeutic dose were continued to the maintenance phase. Therapeutic dose was defined as a dose at which mUFC level was ≤ ULN, or maximum allowed dose (600 mg twice daily) had been reached, or a clinically meaningful partial response based on clinical judgement, and the maximum tolerated dose had been reached.
Maintenance Phase (6 months)
Seventy-seven (77) patients who achieved a therapeutic dose in the dose titration phase entered the maintenance phase and continued treatment with therapeutic dose of RECORLEV for 6 months. The dose of RECORLEV was allowed to be decreased for safety or tolerability reasons or increased for loss of efficacy. The primary efficacy endpoint was evaluated at the end of maintenance phase.
Extended Evaluation Phase (6 months)
Sixty (60) patients entered the extended evaluation phase in which treatment with RECORLEV continued for an additional 6 months.
Efficacy Assessment and Results
The primary efficacy endpoint of the study was the proportion of patients with normalization of mUFC at the end of the 6-month maintenance phase. Normalization of mUFC was defined as mUFC at or below the ULN based on central laboratory result without requiring a dose increase during the maintenance phase. At the end of the maintenance phase, 29 of 94 patients (30.9%, 95% exact confidence interval 21.7%, 41.2%) met the primary endpoint.
Out of the 94 patients who enrolled in Study 2, 63 (67%) patients had normal mUFC at the end of the titration phase, 29 (30.9%) patients had normal mUFC at the end of the maintenance phase without any dose increase during the maintenance phase, and 16 (17%) patients had normal mUFC at the end of the extended evaluation phase without dose increase during maintenance or extended evaluation phase. However, because 51% of patients discontinued treatment prematurely due to adverse reaction, lack of efficacy, or other reasons, these results should be interpreted with caution.