Patient description: The patients is a 25-year-old G1 P1 pregnant woman who is 24W3D gestational old who developed a sudden unset of fever and chills, accompany with nausea and vomiting. She also complains of dysuria, urgency and frequency. She also reports some severe pain in the flank. Her vital signs are: T = 39.7ºC, P = 117, R = 20, and BP = 113/74 mm Hg. Physical examination reveals tenderness on palpation of both costovertebral angles. She has no history of recurrent UTI prior to her pregnancy or any other underlying disease. The urine culture showed Gram-negative rod-shaped bacterial cells, leukocytes, and leukocyte casts. The blood culture is negative. A CBC shows Hb 12.9 g/dL, Hct 39%, MCV 76 fL, WBC count 14,120/µL.

Clinical trial eligibility criteria: eligible ages (years): 18.0-85.0,  Renal Insufficiency Healthy General for all subjects Signed informed consent in the local language prior to any study mandated procedure Male and female subjects aged 18 to 85 years (inclusive) at screening Body mass index (BMI) from 18 to 35 kg/m2 (inclusive) at screening. Body weight at least 50 kg Women of childbearing potential: Women must have a negative serum pregnancy test at screening and a negative urine pregnancy test on Day -1. They must consistently and correctly use (during the entire study and 30 days thereafter) a highly effective method of contraception with a failure rate of < 1% per year Women of non-childbearing potential, i.e., postmenopausal, XY genotype, Turner syndrome, uterine agenesis: no contraceptive requirement. Additional for healthy subjects (Group A) Normal renal function as confirmed based on Creatinine Clearance (CLcr) by the Cockcroft-Gault equation adjusted for age: >= 80 mL/min for subjects <= 50 years of age; >= 70 mL/min for subjects 51-60 years of age; >= 60 mL/min for subjects 61-85 years of age; CLcr = ([140-age(years)]×weight (kg))/(72×serum creatinine (mg/dL)) (x 0.85 for female subjects) The CLcr value should be confirmed (± 25%) on Day -1 in case subjects will be dosed more than 10 days after the day of screening Hematology, clinical chemistry, and urinalysis test results not deviating from the normal range to a clinically relevant extent at screening Each healthy subject must be matched with one subject with severe renal function impairment with regard to age (± 10 years difference allowed), body weight (± 15% difference allowed), and sex, determined by results at screening. Additional for subjects with severe renal function impairment (Group B)  for all subjects Pregnant or lactating women Clinically relevant history of fainting, collapse, syncope, orthostatic hypotension, or vasovagal History of renal and/or liver transplant Hepatic cancer, primary biliary cirrhosis or any form of cholestatic disease Use of drugs which might interfere with the PK of ACT-541468 (moderate to strong CYP3A4 inhibitors or inducers) Any circumstances or conditions, which, in the opinion of the investigator, may affect full participation in the study or compliance with the protocol. Additional for healthy subjects (Group A) History or clinical evidence of any unstable disease and/or existence of any surgical or medical condition, which might interfere with the absorption, distribution, metabolism or excretion of the study treatment (appendectomy, herniotomy, and cholecystectomy allowed) Intake of any creatine supplement from screening to EOS. Additional