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Riociguat

Phase 3

Hypertension, Pulmonary | Small molecule | Cardiovascular |Merck & Company, Inc.|Last Updated: Jul 1, 2026

Target and mechanism

Molecular targetGUCY1B1, GUCY1A2, GUCY1A1
Target classPositive Allosteric Modulator
ModalitySmall molecule

Also known as Riociguat (Adempas, BAY63-2521)

Success Probability

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Market & Valuation

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Trial Design

UNCONTROLLEDDMC
Total Trials1
Total Enrollment24

FDA Designations

No designations recorded

Clinical trial landscape

Riociguat · 1 trial · 1 indication

Phase 3 1
NCT02562235Riociguat in Children With Pulmonary Arterial Hypertension (PAH)Hypertension, Pulmonary
ACTIVE NOT_RECRUITING24 Analytics
PHASE3ACTIVE NOT_RECRUITING
Riociguat in Children With Pulmonary Arterial Hypertension (PAH)
Hypertension, PulmonaryUnlock trial analytics

Study Endpoints

Primary Endpoints

Number of Participants With Any Treatment-emergent Adverse Events
From start of study drug up to 2 days after the last dose of study drug in the main study part, up to 24 weeks plus/minus 5 days.

An adverse event (AE), including AE in relation to a medical device (i.e. Raumedic dosing pipette), is any untoward medical occurrence in a participant administered with a pharmaceutical product and does not necessarily have to have a causal relationship with this treatment. A serious AE (SAE) is any untoward medical occurrence that at any dose is resulting in death, is lifethreatening, requires hospitalization or prolongation of existing hospitalization, results in persistent or significant disability/incapacity. AEs occurring between start of study drug and up to 2 days after the last dose were defined as treatment-emergent AEs (TEAEs).

Change in Heart Rate From Baseline
Baseline and Week 24 (plus/minus 5 days)

Mean change in heart rate from baseline is reported.

Change in Blood Pressure From Baseline
Baseline and Week 24 (plus/minus 5 days)

Mean changes in systolic blood pressure (SBP) and diastolic blood pressure (DBP) from baseline are reported.

Change in Respiratory Rate From Baseline
Baseline and Week 24 (plus/minus 5 days)

Mean change in respiratory rate from baseline is reported.

Number of Subjects With Transitions From Baseline in Bone Age Compared to Chronological Age
Baseline and Week 24 (plus/minus 5 days)

X-ray of left hand was performed for each participant and bone age was determined centrally by a specialist. For each participant, the bone age was compared to the chronological age and assigned to one of the categories - "delayed", "in accordance" or "advanced", indicating the advancement or delay in the growth of the bone. Number of participants who transitioned to another category different from baseline was calculated and is reported.

Change in Hematology Parameters (Platelets) From Baseline
Baseline and Week 24 (plus/minus 5 days)

Hematology parameters were collected. Parameters with a decrease or increase in the mean value compared to baseline are reported in this data set.

Change in Hematology Parameters (Lymphocytes/Leucocytes Ratio) From Baseline
Baseline and Week 24 (plus/minus 5 days)

Hematology parameters were collected. Parameters with a decrease or increase in the mean value compared to baseline are reported in this data set.

Change in Hematology Parameter (Neutrophils/Leucocytes Ratio) From Baseline
Baseline and Week 24 (plus/minus 5 days)

Hematology parameters were collected. Parameters with a decrease or increase in the mean value compared to baseline are reported in this data set.

Change in Clinical Chemistry (Alanine Aminotransferase) From Baseline
Baseline and Week 24 (plus/minus 5 days)

Clinical chemistry parameters were collected and analyzed. Parameters with a trend to lower or higher mean values from baseline are reported in this data set.

Change in Clinical Chemistry (Aspartate Aminotransferase) From Baseline
Baseline and Week 24 (plus/minus 5 days)

Clinical chemistry parameters were collected and analyzed. Parameters with a trend to lower or higher mean values from baseline are reported in this data set.

Change in Clinical Chemistry (Sodium) From Baseline
Baseline and Week 24 (plus/minus 5 days)

Clinical chemistry parameters were collected and analyzed. Parameters with a trend to lower or higher mean values from baseline are reported in this data set.

Change in Clinical Chemistry (Blood Urea Nitrogen) From Baseline
Baseline and Week 24 (plus/minus 5 days)

Clinical chemistry parameters were collected and analyzed. Parameters with a trend to lower or higher mean values from baseline are reported in this data set.

Change in Clinical Chemistry (eGFR) From Baseline
Baseline and Week 24 (plus/minus 5 days)

Clinical chemistry parameters were collected and analyzed. Parameters with a trend to lower or higher mean values from baseline are reported in this data set. eGFR = estimated glomerular filtration rate

Change in Clinical Chemistry (Urea) From Baseline
Baseline and Week 24 (plus/minus 5 days)

Clinical chemistry parameters were collected and analyzed. Parameters with a trend to lower or higher mean values from baseline are reported in this data set.

Change in Clinical Chemistry (Gamma Glutamyl Transferase) From Baseline
Baseline and Week 24 (plus/minus 5 days)

Clinical chemistry parameters were collected and analyzed. Parameters with a trend to lower or higher mean values from baseline are reported in this data set.

Plasma Concentration of Riociguat at Week 0
Week 0 (30-90 minutes post-dose; 2.5-4 hours post-dose)

For each participant, one blood sample was collected at one given time point. Values below lower limit of quantification (LLOQ) were substituted by 1/2 LLOQ for the calculation in statistics. Means at any time were only calculated if at least 2/3 of the individual data were measured and were above the limit of quantification (LOQ). Geometric mean and percentage geometric coefficient of variation (%CV) are reported. W = Week.

Plasma Concentration of Riociguat at Week 4
Week 4 (pre-dose)

For each participant, one blood sample was collected at one given time point. Values below lower limit of quantification (LLOQ) were substituted by 1/2 LLOQ for the calculation in statistics. Means at any time were only calculated if at least 2/3 of the individual data were measured and were above the limit of quantification (LOQ). Geometric mean and percentage geometric coefficient of variation (%CV) are reported.

Plasma Concentration of Riociguat at Week 8
Week 8 (pre-dose)

For each participant, one blood sample was collected at one given time point. Values below lower limit of quantification (LLOQ) were substituted by 1/2 LLOQ for the calculation in statistics. Means at any time were only calculated if at least 2/3 of the individual data were measured and were above the limit of quantification (LOQ). Geometric mean and percentage geometric coefficient of variation (%CV) are reported.

Plasma Concentration of BAY60-4552 at Week 0
Week 0 (30-90 minutes post-dose; 2.5-4 hours post-dose)

BAY60-4552 is riociguat's active metabolite. For each participant, one blood sample was collected at one given time point and in that sample both riociguat and BAY60-4552 were measured. Values below lower limit of quantification (LLOQ) were substituted by 1/2 LLOQ for the calculation in statistics. Means at any time were only calculated if at least 2/3 of the individual data were measured and were above the limit of quantification (LOQ). Geometric mean and percentage geometric coefficient of variation (%CV) are reported. W = Week

Plasma Concentration of BAY60-4552 at Week 4
Week 4 (pre-dose)

BAY60-4552 is riociguat's active metabolite. For each participant, one blood sample was collected at one given time point and in that sample both riociguat and BAY60-4552 were measured. Values below lower limit of quantification (LLOQ) were substituted by 1/2 LLOQ for the calculation in statistics. Means at any time were only calculated if at least 2/3 of the individual data were measured and were above the limit of quantification (LOQ). Geometric mean and percentage geometric coefficient of variation (%CV) are reported.

Plasma Concentration of BAY60-4552 at Week 8
Week 8 (pre-dose)

BAY60-4552 is riociguat's active metabolite. For each participant, one blood sample was collected at one given time point and in that sample both riociguat and BAY60-4552 were measured. Values below lower limit of quantification (LLOQ) were substituted by 1/2 LLOQ for the calculation in statistics. Means at any time were only calculated if at least 2/3 of the individual data were measured and were above the limit of quantification (LOQ). Geometric mean and percentage geometric coefficient of variation (%CV) are reported.

Secondary Endpoints

Change in 6-minute Walking Distance From Baseline
Baseline and Week 24 (plus/minus 5 days)
Number of Subjects With Change in WHO Functional Class From Baseline
Baseline and Week 24 (plus/minus 5 days)
Change in NT-proBNP From Baseline
Baseline and Week 24 (plus/minus 5 days)
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Study Design & Arms

AllocationNA
MaskingNONE
ModelSINGLE_GROUP
PurposeTREATMENT

Treatment Arms

ArmTypeDescription
RiociguatEXPERIMENTALParticipants with age ≥6 to \<18 years received riociguat up to 2.5 mg three times a day (titration between 1.0 mg and 2.5 mg) for up to 8 weeks during the individual dose titration (IDT) phase, and followed with the last dose administered in the IDT phase for up to 16 weeks during the maintenance phase. Down-titration (up to 0.5 mg) of the dose for safety reasons was allowed at any time.

Interventions

NameTypeDescription
Riociguat (Adempas, BAY63-2521)DRUGFor children with body-weight \<50 kg at screening: body-weight adjusted dose equivalent to the exposure of (0.5 mg) 1.0 - 2.5 mg three times a day, IDT in adults treated for PAH; oral suspension. For children ≥50 kg at screening: 1.0 to 2.5 mg three times a day; oral tablet.
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Eligibility Criteria

Age Range6 Years to 17 Years
SexALL
Healthy VolunteersNo
Study Sites16

Inclusion Criteria: * Children from 6 years to less than 18 years of age with pulmonary arterial hypertension (PAH) * Diagnosed with PAH : * Idiopathic (IPAH) * Hereditable (HPAH) * PAH associated with (APAH) * Connective tissue disease * Congenital heart disease with shunt closure ...

Countries:ColombiaGermanyHungaryItalyJapanMexicoPolandTaiwanTurkey (Türkiye)
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Recent Changes (Last 90 Days)

LOWJul 5, 2026NCT02562235primaryCompletionDate: changed
LOWJul 5, 2026NCT02562235primaryCompletionDate: changed
LOWJul 5, 2026NCT02562235primaryCompletionDate: changed

Frequently asked questions about Riociguat

What is Riociguat used for?

Riociguat is a small molecule being studied for the treatment of pulmonary hypertension, specifically in children with pulmonary arterial hypertension (PAH). It is currently in Phase 3 clinical development and is not yet approved for this pediatric indication.

What does Riociguat target?

Riociguat targets the soluble guanylate cyclase (sGC) enzyme, specifically the GUCY1B1, GUCY1A2, and GUCY1A1 subunits. It acts as a positive allosteric modulator, which means it enhances the enzyme's activity to promote vasodilation and reduce blood pressure in the pulmonary arteries.

Who makes Riociguat?

Riociguat is being developed by Merck & Company, Inc., which trades under the ticker symbol MRK on the New York Stock Exchange. The company is conducting clinical trials to evaluate the drug's safety and efficacy in pediatric patients with pulmonary arterial hypertension.

What phase is Riociguat in?

Riociguat is in Phase 3 clinical development for the treatment of pulmonary hypertension in children. It is an investigational drug for this indication and has not yet received regulatory approval. The ongoing Phase 3 trial is active but not recruiting participants.

What clinical trials is Riociguat in?

Riociguat is being evaluated in a Phase 3 clinical trial with the identifier NCT02562235, titled 'Riociguat in Children With Pulmonary Arterial Hypertension (PAH).' This single-arm, uncontrolled study has an enrollment of 24 participants and is being conducted across multiple countries, including Colombia, Germany, Hungary, Italy, Japan, Mexico, Poland, Taiwan, and Turkey.

Is Riociguat the same as Adempas?

Yes, Riociguat is also known as Adempas and BAY63-2521. Adempas is the brand name under which the drug has been marketed for other indications, while BAY63-2521 is the original research code. In the context of pediatric pulmonary hypertension, it is being studied under the name Riociguat.