A Single and Multiple Ascending Dose Escalation and Food Effect Study of QX-4533 in Healthy Participants

This study will consist of 3 parts: Part 1: A randomized, double-blind, placebo-controlled single ascending dose (SAD) evaluation, including an open-label crossover food effect (FE) assessment in 1 cohort.

Part 2: A 14-day randomized, double-blind, placebo-controlled multiple ascending dose (MAD) evaluation.

Part 3: An open-label, 2-period crossover FE assessment.

Inclusion criteria

• Male or female between 18 and 55 years of age (inclusive) at screening.
• Understands the study procedures and is capable of giving signed informed consent, which includes compliance with the requirements and restrictions listed in the informed consent form (ICF) and in this protocol.
• Willing and able to comply with this protocol and be available for the entire duration of the study.
• In good general health, determined by no clinically significant findings in the opinion of the Investigator from medical history, physical examination, 12-lead electrocardiogram (ECG), clinical laboratory findings, and vital signs at screening and Day -1.
• Has body mass index of 18 to 32 kilograms per meter square (kg/m^2) inclusive.

Exclusion criteria

• History or presence of significant cardiovascular, pulmonary, hepatic, renal, hematologic, gastrointestinal, endocrine, immunologic, dermatologic, or neurologic disease according to the Investigator.
• History of any Gastrointestinal (GI) procedures (e.g., bariatric surgery) that could impair gastrointestinal absorption.
• History of any illness that, in the opinion of the Investigator, might confound the results of the study or pose additional risk to the participant.
• Clinically significant abnormalities on pre-study clinical examination or laboratory safety tests. Laboratory safety assessments (e.g., serum chemistry, hematology, coagulation) will be performed at screening and on Day -1 (if screening is prior to Day -1) to confirm eligibility.
• Treatment with a live (attenuated) vaccine within 8 weeks before the screening visit.
• Positive hepatitis B surface antigen, human immunodeficiency virus antibody, or hepatitis C antibody at the screening visit.
• Use of any prescription within 14 days prior to study treatment administration or use of any over-the-counter medications including food supplements and herbal medications (e.g., St. John's wort), except for contraceptive medications and as needed (pro re nata) paracetamol (not exceeding 2 g/day) within 7 days prior to study treatment administration.
• Participant has participated in another clinical study within the last 4 weeks or within 5 half-lives of the prior study drug, whichever is longer.
• Participants that currently use (including "recreational use") any illicit drugs or have a history of drug abuse in the last 2 years.