GSK3915393 is a new medicine which is being developed for a chronic lung disease called Idiopathic Pulmonary Fibrosis (IPF). This is a healthy participant study which has two parts. Part A will assess the safety, tolerability, and blood levels of GSK3915393 given as a single dose to healthy participants of Chinese, Japanese, and European ancestries. Part B is a drug-drug interaction (DDI) study that examines the effect of a single dose of GSK3915393 on the blood levels of a single dose of nintedanib, which is an approved drug for IPF.

Inclusion Criteria:

For Part A and Part B:

Participants who are generally healthy as determined by medical evaluation based on screening medical history, physical examination, vital signs, electrocardiogram (ECG) assessments, and laboratory tests Body weight at least 50.0 kilograms (kg) (110 pounds [lbs]) for male participants (Part A and Part B) or at least 45.0 kg (99 lbs) for female participants (Part A only) Body mass index (BMI) within the range of 18.0 to 28.0 kilogram per square meter (kg/m^2) (inclusive) Capable of giving signed informed consent which includes compliance with the requirements and restrictions listed in the informed consent form (ICF)

For Part A:

Female Participants: A female participant is eligible to participate if she is not pregnant or breastfeeding, and at least one of the following conditions applies:

Is a woman of non-childbearing potential (WONCBP) Is a woman of childbearing potential (WOCBP) and using an acceptable contraceptive method prior to and during the study intervention period (at a minimum until after the last dose of study intervention). The investigator should evaluate the potential for contraceptive method failure (for example, noncompliance, recently initiated in relationship to the first dose of study intervention) A WOCBP must have a negative highly sensitive pregnancy test within 30 days before the first dose of study intervention Participants of Chinese ancestry are eligible if born in mainland China, Hong Kong or Taiwan; descendant of four ethnic Chinese grandparents and two ethnic Chinese parents; and have lived outside China, Hong Kong or Taiwan for less than 10 years at the time of screening Participants of Japanese ancestry are eligible if born in Japan; Descendant of four ethnic Japanese grandparents and two ethnic Japanese parents; and have lived outside Japan for less than 10 years at the time of screening Participants of European ancestry are eligible if Self-identified as being of European ancestry (i.e. from the original peoples of Europe) irrespective of current place of residence; and descendant of four grandparents and two parents of European ancestry

Exclusion Criteria:

History or presence of cardiovascular, respiratory, hepatic, renal, gastrointestinal, endocrine, hematological, or neurological disorders capable of significantly altering the absorption, metabolism, or elimination of drugs; constituting a risk when taking the study intervention or interfering with the interpretation of data Participants with systolic blood pressure (BP) greater than (>) 140 millimeter of mercury (mmHg) or diastolic BP > 90 mmHg at screening or pulse rate outside the range of 40 to 100 beats per minute (bpm) will be excluded from the study Alanine transaminase (ALT) or aspartate aminotransferase (AST) >1× upper limit of normal (ULN) Total bilirubin >1.5×ULN; Participants with Gilbert's syndrome can be included with total bilirubin >1.5×ULN as long as direct bilirubin is less than or equal to (≤) 1.5×ULN Current or chronic history of liver disease or known hepatic or biliary abnormalities (with the exception of Gilbert's syndrome or asymptomatic gallstones) QT interval corrected (QTc) >450 milliseconds (msec) at Screening visit based on the average of triplicate ECGs Unable to refrain from the use of prescription or non-prescription drugs, including vitamins, probiotics, antacids, herbal and dietary supplements (including St John's Wort) within 7 days (or 14 days if the drug is a potential enzyme inducer) or 5 half-lives (whichever is longer) prior to the first dose of study intervention, unless in the opinion of the Investigator and the Medical Monitor, the medication will not interfere with the study procedures or compromise participant safety

GSK will assess requests from qualified researchers for anonymized individual patient-level data and related study documents. Data sharing is subject to certain criteria, conditions, and exceptions. For further information, refer to https://www.gsk-studyregister.com/About\_GSK\_Patient\_Level\_Data\_Sharing\_Final\_13July2023.pdf

Anonymized IPD will be made available within 6 months of publication of primary, key secondary and safety results for studies in product with approved indication(s) or asset(s) with development terminated across all indications.

Anonymized IPD is shared with researchers whose proposals are approved by an Independent Review Panel and after a Data Sharing Agreement is in place. Access is provided for an initial period of 12 months, but an extension may be granted, when justified, for up to 6 months.

Part A is a double-blind study and Part B is an open-label study.