The purpose of this study is to evaluate the pharmacokinetics (PK) of a single oral dose of lazertinib in participants with impaired hepatic function when compared with healthy participants with normal hepatic function, under fed conditions.

Inclusion Criteria:

All Participants:

• Must have a clinically stable hepatic function as confirmed by the serum bilirubin and transaminase levels measured during screening and those measured on Day -1
• Willing and able to adhere to the prohibitions and restrictions specified in this protocol
• If a woman, must not be of childbearing potential: postmenopausal (amenorrhea for at least 12 months and a serum follicle stimulating hormone within postmenopausal range); or surgically sterile (hysterectomy, bilateral salpingectomy, bilateral oophorectomy, bilateral tubal occlusion/ligation procedure)

Healthy Participants with normal hepatic function:

• Blood pressure (after the participant is supine for 5 minutes) between 90 and 140 millimeter of mercury (mmHg) systolic for participants less than or equal to (<=) 60 years old and between 90 and 150 mmHg for participants greater than (>) 60 years old, inclusive, and no higher than 90 mmHg diastolic. If blood pressure is out of range, up to 2 repeated assessments are permitted per visit
• Pharmacogenomics: Healthy participants must have matching glutathione S-transferase Mu 1 (GSTM1) genotype (null or non-null GSTM1 genotype) to individual hepatic impairment group participants

Participants with hepatic impairment:

• A 12-lead electrocardiogram (ECG) consistent with adequate cardiac conduction and function as per judgement by the investigator, including: a) Sinus rhythm; b) Heart rate between 50 and 100 beats per minute (extremes included); c) QTc interval <= 480 milliseconds (ms) (corrected cf. Fridericia; QTcF)
• Concomitant medications to treat underlying disease states or medical conditions related to hepatic impairment are allowed. Participants must be on a stable dose of medication and/or treatment regimen for at least 2 weeks before dosing as well as during the study

Exclusion Criteria:

All Participants:

• Participant has known allergies, hypersensitivity, or intolerance to Lazertinib or its excipients
• Any surgical or medical condition that may alter the absorption, metabolism, or excretion of the study drug (example, gastrectomy, Crohn's disease etc.), with the exception of hepatic impairment
• Active gall bladder or biliary tract disease (example, acute cholecystitis, symptomatic cholelithiasis)
• Participant tests positive for human immunodeficiency virus (HIV)-1 or HIV-2 at screening
• Participant has a lack of adequate venous access

The data sharing policy of the Janssen Pharmaceutical Companies of Johnson & Johnson is available at www.janssen.com/clinical-trials/transparency. As noted on this site, requests for access to the study data can be submitted through Yale Open Data Access (YODA) Project site at yoda.yale.edu