The purpose of this study is to evaluate the effect of varying degrees of hepatic function on the single dose PK of IV TAK-954.

The drug being tested in this study is called TAK-954. This study will evaluate the safety and tolerability of single intravenous doses of TAK-954 in participants with varying degrees of hepatic function.

The study will enroll approximately up to 32 participants. Participants will be enrolled in one of the 4 treatment groups based on their degree of hepatic impairment which will be determined based on Child-Pugh Score as follow:

• Group 1 TAK-954 0.2 mg: Mild Hepatic Impairment (Child Pugh Class A)
• Group 2 TAK-954 0.2 mg: Moderate Hepatic Impairment (Child Pugh Class B)
• Group 3 TAK-954 0.2 mg: Severe Hepatic Impairment (Child Pugh Class C)
• Group 4 TAK-954 0.2 mg: Healthy Participants

The Child-Pugh classification will assess the severity of 5 hepatic parameters (total serum bilirubin, serum albumin, prothrombin time, ascites and encephalopathy grade) on a scale of 1 (none) to 3 (moderate). Total hepatic impairment score ranges from 5 (mild) to 15 (severe) where higher score indicates more severity.

All participants will receive a single dose of TAK-954 0.2 mg on Day 1.

This study may have a full study design, where Group 1 to Group 4 will enroll approximately 8 participants in each group or a reduced study design, where no participants will be enrolled in Group 1 and approximately 8 participants will be enrolled in Group 2 to Group 4.

This multi-center trial will be conducted in Czech Republic and Slovakia. The overall time to participate in this study is approximately 7 weeks. Participants will remain confined to the clinic for 4 days, with 2 further out-patient visits, and will make a final visit to the clinic 10-14 days after receiving their last dose of TAK-954 for a follow-up assessment.

Inclusion Criteria:

1. Male and female participants (non-childbearing potential), with a body mass index (BMI) between 18 to 35 kilogram per square meter (kg/m^2) (All participants).
2. Participants with hepatic impairment who are medically stable as determined by the investigator, based on medical history and clinical evaluations including physical examinations, clinical laboratory tests, vital sign measurements, and 12-lead ECGs performed at the Screening Visit and at check-in on Day -1 (Group 1 to 3).
3. Healthy participants (Group 4).

Exclusion Criteria:

Participants who have:

1. A history of hepatic carcinoma, hepatorenal syndrome, or presence of a liver mass by ultrasound, CT or MRI, or acute liver disease caused by an infection or drug toxicity (Group 1 to 3).
2. Have severe hepatic encephalopathy ([greater than] > Grade II Portal Systemic Encephalopathy Score) (Group 1 to 3).
3. Surgical porto-systemic shunts, including transjugular intrahepatic portosystemic shunt (Group 1 to 3).
4. A history of gastrointestinal hemorrhage due to esophageal varices or peptic ulcers less than 1 month prior to trial entry (Group 1 to 3).
5. Bilirubin levels above 5 times the upper limit of normal (ULN) at screening or Day -1 for Groups 1 and 2, there is no limit for Group 3.
6. Severe/advanced ascites and/or pleural effusion which requires emptying and albumin supplementation, as judged by the investigator (Group 1 to 3).
7. Renal creatinine clearance (CLcr) less than or equal to (<=) 50 milliliter per minute (mL/min), calculated using the Cockcroft-Gault equation from the serum creatinine measurement taken at screening (Group 1 to 3).
8. Who have a history of clinically significant endocrine, gastrointestinal (GI) (including motility disorder and intestinal obstruction), cardiovascular, hematological, hepatic, immunological, renal, respiratory, genitourinary, or major neurological (including stroke and chronic seizures) abnormalities or diseases will be excluded from the trial (Group 4).

Takeda makes patient-level, de-identified data sets and associated documents available for all interventional studies after applicable marketing approvals and commercial availability have been received (or program is completely terminated), an opportunity for the primary publication of the research and final report development has been allowed, and other criteria have been met as set forth in Takeda's Data Sharing Policy (see www.TakedaClinicalTrials.com for details). To obtain access, researchers must submit a legitimate academic research proposal for adjudication by an independent review panel, who will review the scientific merit of the research and the requestor's qualifications and conflict of interest that can result in potential bias. Once approved, qualified researchers who sign a data sharing agreement are provided access to these data in a secure research environment.

The safety set consisted of all participants who were enrolled and received the study drug.

TEAEs are adverse events that started after the first dose of study drug and no more than 30 days (Day 31) after the last dose of study drug

At each visit the investigator had to document any occurrence of adverse events and abnormal laboratory findings. Any event spontaneously reported by the participant or observed by the investigator was recorded, irrespective of the relation to study treatment.