The purpose of the study is to assess the effects of multiple doses of itraconazole (a strong CYP3A4 inhibitor) on single dose PK of casdatifan in healthy adults and to assess the effects of multiple doses of phenytoin (a strong CYP3A4 inducer) on single dose PK of casdatifan in healthy adults.

Inclusion Criteria:

• Healthy, adult, male or female 18-55 years of age, inclusive, at the screening visit.
• Male participants must be vasectomized
• Continuous non-smoker who has not used nicotine- and tobacco-containing products for at least 3 months prior to the first dosing based on participant self-reporting.
• BMI ≥ 18.0 and ≤ 32.0 kg/m2 and body weight ≥ 45 kg, at the screening visit
• Able to swallow multiple tablets and/or capsules.

Exclusion Criteria:

• Is mentally or legally incapacitated or has significant emotional problems at the time of the screening visit or expected during the conduct of the study.
• History or presence of clinically significant medical or psychiatric condition or disease in the opinion of the PI or designee.
• History of any illness that, in the opinion of the PI or designee, might confound the results of the study or poses an additional risk to the participant by their participation in the study.
• History or presence of hypersensitivity or idiosyncratic reaction to the study drugs or related compounds.
• History of asthma or chronic obstructive pulmonary disease (including childhood), clinically significant food allergies or anaphylaxis, as deemed by PI or designee.

NOTE: Other protocol defined Inclusion/Exclusion criteria may apply.

Arcus will provide access to individual de-identified participant data and related study documents (e.g., protocol, Statistical Analysis Plan [SAP], Clinical Study Report [CSR]) upon request from qualified researchers, and subject to certain criteria, conditions, and exceptions.