BAY 63-2521 is intended to be used for a disease that affects the blood flow through the lungs. Renal impairment is a common condition in patients with this disease. The goal of the study is to learn more about the safety of BAY 63-2521, how it is tolerated and the way the body absorbs, distributes and gets rid of the study dug given as a single oral dose of 1 mg tablet in participants with renal impairment and healthy participants matched for age-, gender-, and weight

Inclusion criteria for all subjects:

• Male and female white subjects with 18 to ≤79 years of age, BMI between 18 and 34 kg/m^2
• Women without childbearing potential or with childbearing potential but only if the pregnancy test is negative and are under highly effective contraception

Inclusion criteria for subjects with renal failure:

- Stable renal disease, ie. a serum creatinine value determined at least 3 - 6 months before the pre-study visit was not allowed to vary by more than 20% from the serum creatinine value determined at the pre-study visit

Inclusion criteria for healthy subjects:

- Mean age and body weight not allowed to vary by more than +/- 10 years and +/- 10 kg from the subjects with renal impairment, respectively

Exclusion criteria for all subjects:

• Febrile illness within 1 week before the start of the study
• Hypersensitivity to riociguat and / or to inactive constituents
• Smoking

Exclusion criteria for subjects with renal failure:

• Resting heart rate in the awake subject below 45 BPM or above 90 BPM
• Acute renal failure or nephritis
• Any organ transplant
• Diastolic blood pressure (DBP) >100 mmHg and / or systolic blood pressure (SBP) >180 mmHg
• Hemoglobin <8 g/dL, Proteinuria >8 g/24 hours, Serum albumin <30 g/L, Platelet count <100 x 109/L
• History of bleeding within the past 3 months
• Diabetes mellitus with a fasting blood glucose >220 mg/dL or HbA1c >10%
• Concomitant use of any medication except medications necessary for the treatment of the kidney disease or related complications
• Concomitant use of phosphodiesterase-5 inhibitors, endothelin receptor antagonists (ERAs, eg bosentan), intravenous or inhalative prostacyclins, or nitrates
• Concomitant use of potent CYP3A4 inhibitors

Exclusion criteria for healthy subjects:

• Conspicuous findings in medical history or pre-study examination
• History of relevant diseases of vital organs, central nervous system, or other organs
• SBP below 100 mmHg or above 145 mmHg and / or DBP above 95 mmHg
• Regular daily consumption of more than 1 liter of usual beer or the equivalent quantity of approximately 40 g of alcohol in another form

Availability of this study's data will be determined according to Bayer's commitment to the EFPIA/PhRMA "Principles for responsible clinical trial data sharing". This pertains to scope, timepoint and process of data access. As such, Bayer commits to sharing upon request from qualified researchers patient-level clinical trial data, study-level clinical trial data, and protocols from clinical trials in patients for medicines and indications approved in the US and EU as necessary for conducting legitimate research. This applies to data on new medicines and indications that have been approved by the EU and US regulatory agencies on or after January 01, 2014. Interested researchers can use www.clinicalstudydatarequest.com to request access to anonymized patient-level data and supporting documents from clinical studies to conduct research. Information on the Bayer criteria for listing studies and other relevant information is provided in the Study sponsors section of the portal.