This study of frespaciguat in participants with Group 1 pulmonary arterial hypertension (PAH) will assess the safety, tolerability and pharmacokinetics (PK) of inhaled frespaciguat. There is no formal hypothesis to be tested.
In Part 1, one panel (Panel A) of up to 8 participants will dose in up to 3 dosing periods, with a minimum washout of 7 days between dosing periods. In each dosing period, 6 participants will receive frespaciguat and 2 will receive placebo, with 2 different participants receiving placebo in each of the dosing periods. Review of available safety data will occur prior to escalating to the next dose level. Participants from Part 1 may continue into Part 2, which will assess safety, tolerability, pharmacokinetics (PK) and pharmacodynamics (PD) of single-dose inhaled frespaciguat. Three additional panels of participants (Panels B, C and D) will be enrolled into Part 2. Participants in Panel A will participate in 2 open-label dosing periods to assess PD measures associated with right heart catherization (RHC) \[Period 2\] and functional respiratory imaging (FRI) \[Period 3\]. Participants in Panels B, C, and D will participate in 3 dosing periods: Period 1 (open-label assessment of safety/tolerability and PK), Period 2 (FRI period) and Period 3 (RHC period).
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
25
Single inhaled dose of frespaciguat 120, 165, 240, 300, 360, or 480 ug depending upon randomization
Single inhaled dose of placebo to match frespaciguat
Republican Clinical Hospital of Moldova ( Site 0001)
Chisinau, Moldova
Number of Participants Who Experienced at Least 1 Adverse Event (AE): All Parts
An AE was defined as any untoward medical occurrence in a participant which may not necessarily have a causal relationship with the treatment. An AE could therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease that was temporally associated with use of a medicinal product, regardless of whether or not it was considered related to the medicinal product. The number of participants who experienced at least 1 AE was reported by dose separately for Part 1 plus Part 2 Period 1, for the RHC Period, and for the FRI Period.
Time frame: Up to ~14 days after last dose of treatment period (Up to ~32 weeks total)
Number of Participants Who Discontinued From the Study Due to an AE: All Parts
An AE was defined as any untoward medical occurrence in a participant which may not necessarily have a causal relationship with the treatment. An AE could therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease that was temporally associated with use of a medicinal product, regardless of whether or not it was considered related to the medicinal product. The number of participants who discontinued from the study due to an AE was reported by dose separately for Part 1 plus Part 2 Period 1, for the RHC Period, and for the FRI Period.
Time frame: Up to ~14 days after last dose of treatment period (Up to ~32 weeks total)
Percentage Change From Baseline in Minimum Pulmonary Vascular Resistance (PVR): Part 2 Right Heart Catheterization (RHC) Period
For each participant in the RHC Period, the percentage change from baseline for the minimum post-dose PVR value over the duration of the RHC procedure was calculated. The average of pre-dose measurements was set as the baseline. Mean (SD) percent change from baseline in PVR minimum were calculated and reported for each dose group that underwent RHC in Part 2. Per protocol, this outcome measure was only assessed during the Part 2 RHC Period for each panel and was not assessed during Part 1.
Time frame: Baseline: Pre-dose on Day 1 of RHC Period (up to 185 days) and up to 4.5 hours post-dose
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Change From Baseline in Heart Rate (HR) at 0.5 Hours Post-dose: Part 2 RHC Period
HR was assessed at pre-dose in the RHC Period (baseline) and at 0.5 hours post-dose. Baseline HR and change from baseline in HR was reported for each panel/dose group that underwent RHC in Part 2, according to treatment planned. Negative values indicate decreases from baseline in HR. Per protocol, this outcome measure was only assessed during the Part 2 RHC Period for each panel and was not assessed during Part 1.
Time frame: Baseline: Pre-dose on Day 1 of RHC Period (up to 185 days) and 0.5 hours post-dose
Change From Baseline in Heart Rate (HR) at 4.5 Hours Post-dose: Part 2 RHC Period
HR was assessed at pre-dose in the RHC Period (baseline) and at 4.5 hours post-dose. Baseline HR and change from baseline in HR was reported for each panel/dose group that underwent RHC in Part 2, according to treatment planned. Negative values indicate decreases from baseline in HR. Per protocol, this outcome measure was only assessed during the Part 2 RHC Period for each panel and was not assessed during Part 1.
Time frame: Baseline: Pre-dose on Day 1 of RHC Period (up to 185 days) and 4.5 hours post-dose
Change From Baseline in Heart Rate (HR) at 24 Hours Post-dose: Part 2 RHC Period
HR was assessed at pre-dose in the RHC Period (baseline) and at 24 hours post-dose. Baseline HR and change from baseline in HR was reported for each panel/dose group that underwent RHC in Part 2, according to treatment planned. Negative values indicate decreases from baseline in HR. Per protocol, this outcome measure was only assessed during the Part 2 RHC Period for each panel and was not assessed during Part 1.
Time frame: Baseline: Pre-dose on Day 1 of RHC Period (up to 185 days) and 24 hours post-dose
Change From Baseline in Systolic Blood Pressure (SBP) at 0.5 Hours Post-dose: Part 2 RHC Period
SBP was assessed at pre-dose in the RHC Period (baseline) and at 0.5 hours post-dose. Baseline SBP and change from baseline in SBP was reported for each panel/dose group that underwent RHC in Part 2, according to treatment planned. Negative values indicate decreases from baseline in SBP. Per protocol, this outcome measure was only assessed during the Part 2 RHC Period for each panel and was not assessed during Part 1.
Time frame: Baseline: Pre-dose on Day 1 of RHC Period (up to 185 days) and 0.5 hours post-dose
Change From Baseline in Systolic Blood Pressure (SBP) at 4.5 Hours Post-dose: Part 2 RHC Period
SBP was assessed at pre-dose in the RHC Period (baseline) and at 4.5 hours post-dose. Baseline SBP and change from baseline in SBP was reported for each panel/dose group that underwent RHC in Part 2, according to treatment planned. Negative values indicate decreases from baseline in SBP. Per protocol, this outcome measure was only assessed during the Part 2 RHC Period for each panel and was not assessed during Part 1.
Time frame: Baseline: Pre-dose on Day 1 of RHC Period (up to 185 days) and 4.5 hours post-dose
Change From Baseline in Systolic Blood Pressure (SBP) at 24 Hours Post-dose: Part 2 RHC Period
SBP was assessed at pre-dose in the RHC Period (baseline) and at 24 hours post-dose. Baseline SBP and change from baseline in SBP was reported for each panel/dose group that underwent RHC in Part 2, according to treatment planned. Negative values indicate decreases from baseline in SBP. Per protocol, this outcome measure was only assessed during the Part 2 RHC Period for each panel and was not assessed during Part 1.
Time frame: Baseline: Pre-dose on Day 1 of RHC Period (up to 185 days) and 24 hours post-dose
Change From Baseline in Diastolic Blood Pressure (DBP) at 0.5 Hours Post-dose: Part 2 RHC Period
DBP was assessed at pre-dose in the RHC Period (baseline) and at 0.5 hours post-dose. Baseline DBP and change from baseline in DBP was reported for each panel/dose group that underwent RHC in Part 2, according to treatment planned. Negative values indicate decreases from baseline in DBP. Per protocol, this outcome measure was only assessed during the Part 2 RHC Period for each panel and was not assessed during Part 1.
Time frame: Baseline: Pre-dose on Day 1 of RHC Period (up to 185 days) and 0.5 hours post-dose
Change From Baseline in Diastolic Blood Pressure (DBP) at 4.5 Hours Post-dose: Part 2 RHC Period
DBP was assessed at pre-dose in the RHC Period (baseline) and at 4.5 hours post-dose. Baseline DBP and change from baseline in DBP was reported for each panel/dose group that underwent RHC in Part 2, according to treatment planned. Negative values indicate decreases from baseline in DBP. Per protocol, this outcome measure was only assessed during the Part 2 RHC Period for each panel and was not assessed during Part 1.
Time frame: Baseline: Pre-dose on Day 1 of RHC Period (up to 185 days) and 4.5 hours post-dose
Change From Baseline in Diastolic Blood Pressure (DBP) at 24 Hours Post-dose: Part 2 RHC Period
DBP was assessed at pre-dose in the RHC Period (baseline) and at 24 hours post-dose. Baseline DBP and change from baseline in DBP was reported for each panel/dose group that underwent RHC in Part 2, according to treatment planned. Negative values indicate decreases from baseline in DBP. Per protocol, this outcome measure was only assessed during the Part 2 RHC Period for each panel and was not assessed during Part 1.
Time frame: Baseline: Pre-dose on Day 1 of RHC Period (up to 185 days) and 24 hours post-dose
Area Under the Concentration-Time Curve From Hour 0 to Infinity (AUC0-inf) of MK-5475: All Parts
Blood samples were taken at predose and at specified time points postdose to determine the AUC0-inf of MK-5475. AUC0-inf was defined as the area under the concentration-time curve of MK-5475 from time zero to infinity. MK-5475 AUC0-inf was reported by panel/dose group. Per protocol, percent geometric coefficient of variation (%GCV) values were not reported for groups with n\<2 participants.
Time frame: Part 1 and Part 2 Period 1: Predose and 0.1, 0.25, 0.5, 1, 2, 3, 4, 8, and 24 hours post-dose; RHC Period: predose and 0.25, 0.5, 1, 2, 3, 4, and 4.5 hours; FRI Period: predose and 1, 3, 8, and 24 hours postdose (Panel D also 0.25, 0.5, 2, 4 hours)
Area Under the Concentration-Time Curve From Hour 0 to 24 Hours (AUC0-24hr) of MK-5475: All Parts
Blood samples were taken at predose and at specified time points postdose to determine the AUC0-24hr of MK-5475. AUC0-24hr was defined as the area under the concentration-time curve of MK-5475 from time zero to 24 hours. MK-5475 AUC0-24hr was reported by panel/dose group. For RHC panel/dose groups where sampling was only done up to 4.5 hours, the AUC0-24hr geometric mean represents an extrapolated AUC0-24hr value. Per protocol, %GCV values were not reported for groups with n\<2 participants.
Time frame: Part 1 and Part 2 Period 1: Predose and 0.1, 0.25, 0.5, 1, 2, 3, 4, 8, and 24 hours post-dose; RHC Period: predose and 0.25, 0.5, 1, 2, 3, 4, and 4.5 hours; FRI Period: predose and 1, 3, 8, and 24 hours postdose (Panel D also 0.25, 0.5, 2, 4 hours)
Maximum Concentration (Cmax) of MK-5475: All Parts
Blood samples were taken at predose and at specified time points postdose to determine the Cmax of MK-5475. Cmax was defined as the maximum concentration of MK-5475 reached. MK-5475 Cmax was reported by panel/dose group. Per protocol, %GCV values were not reported for groups with n\<2 participants.
Time frame: Part 1 and Part 2 Period 1: Predose and 0.1, 0.25, 0.5, 1, 2, 3, 4, 8, and 24 hours post-dose; RHC Period: predose and 0.25, 0.5, 1, 2, 3, 4, and 4.5 hours; FRI Period: predose and 1, 3, 8, and 24 hours postdose (Panel D also 0.25, 0.5, 2, 4 hours)
Concentration of MK-5475 at 24 Hours Postdose (C24): All Parts
Blood samples were taken at predose and at specified time points postdose to determine the C24 of MK-5475. C24 was defined as the concentration of MK-5475 reached at 24 hours. MK-5475 Cmax was reported by panel/dose group. Per protocol, %GCV values were not reported for groups with n\<2 participants.
Time frame: 24 hours postdose
Time to Maximum Concentration (Tmax) of MK-5475: All Parts
Blood samples were taken at predose and at specified time points postdose to determine the Tmax of MK-5475. Tmax was defined as the time to maximum concentration of MK-5475. MK-5475 Tmax was reported by panel/dose group.
Time frame: Part 1 and Part 2 Period 1: Predose and 0.1, 0.25, 0.5, 1, 2, 3, 4, 8, and 24 hours post-dose; RHC Period: predose and 0.25, 0.5, 1, 2, 3, 4, and 4.5 hours; FRI Period: predose and 1, 3, 8, and 24 hours postdose (Panel D also 0.25, 0.5, 2, 4 hours)
Apparent Terminal Half-life (t1/2) of MK-5475: All Parts
Blood samples were taken at predose and at specified time points postdose to determine the t½ of MK-5475. t½ was defined as the time required to divide the MK-5475 plasma concentration by two after reaching pseudo-equilibrium, following a single dose of MK-5475. MK-5475 t½ was reported by panel/dose group.
Time frame: Part 1 and Part 2 Period 1: Predose and 0.1, 0.25, 0.5, 1, 2, 3, 4, 8, and 24 hours post-dose; RHC Period: predose and 0.25, 0.5, 1, 2, 3, 4, and 4.5 hours; FRI Period: predose and 1, 3, 8, and 24 hours postdose (Panel D also 0.25, 0.5, 2, 4 hours)
Percentage Change From Baseline in Pulmonary Blood Volume (PBV) Over Time: Part 2 Functional Respiratory Imaging (FRI) Period
Participants underwent a series of computed tomography (CT) scans with an intravenous (IV) iodinated contrast agent to facilitate assessment of PBV at baseline and at several times points after MK-5475 dosing. Percentage change from baseline (CFB) in PBV was calculated and reported for each dose group that underwent FRI in Part 2. As pre-specified, central tendency for PBV percentage CFB was provided as numerical values rounded to whole numbers. Per protocol, this outcome measure was only assessed during the Part 2 FRI Period for each panel and was not assessed during Part 1.
Time frame: Baseline: Pre-dose on Day 1 of FRI Period (up to 227 days) and 1, 3, 8, and 24 hours post-dose