A Study of an Intermittent ADT Approach With Apalutamide Monotherapy in Participants With mCSPC

Inclusion Criteria:

• Diagnosis of prostate cancer prior to screening with histologically or cytologicallyconfirmed adenocarcinoma of the prostate

• For participants not undergoing Gender-affirming care: Metastatic prostate cancerdisease documented by conventional imaging (example, computed tomography [CT],magnetic resonance imaging [MRI], or bone scan) and/or next-generation imaging [NGI]demonstrating greater than equal (>=) 2 distinct extraprostatic sites of metastasis

• For participants undergoing Gender-affirming care: No evidence of metastasis byeither conventional imaging (example, CT, MRI, or bone scan) and/or NGI is alsoacceptable

• For participants not undergoing gender-affirming care: testosterone levels > 50 (ng/dL) nanograms per deciliter at screening, except for those who may have receivedADT prior to screening. Participants are allowed to have received up to 3 months of (ADT) androgen-deprivation therapy prior to enrollment

• For participants undergoing Gender-affirming care: There is no testosterone levelrequirement for inclusion

• Have an Eastern Cooperative Oncology Group Performance Status (ECOG PS) of 0 or 1.Participants with ECOG PS 2 or 3 are eligible for the study if the ECOG PS score isrelated to stable physical limitations (example, wheelchair-bound due to priorspinal cord injury) and not related to prostate cancer or associated therapy

• A participant must agree not to plan to conceive a child while enrolled in thisstudy or within 3 months after the last dose of study treatment

• Must be able to take whole apalutamide tablets by swallowing alone or with anothervehicle (example, applesauce)

• Assigned male at birth, inclusive of all gender identities

Exclusion Criteria:

• History of seizure or known condition that has been determined to significantlypredispose to seizure per investigator

• Pelvic lymph nodes as only site of metastasis

• Known allergies, hypersensitivity, or intolerance to excipients of apalutamide

• Any of the following within 6 months prior to screening: severe or unstable angina,myocardial infarction, symptomatic congestive heart failure, uncontrolledhypertension, clinically significant arterial or venous thromboembolic events

• Gastrointestinal disorder affecting absorption

• Participants who have undergone a bilateral orchiectomy with the exception ofparticipants who completed this as part of their gender-affirming care or a resultof a variation in physical sex development