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 cytologically confirmed adenocarcinoma of the prostate * For participants not undergoing Gender-affirming care: Metastatic prostate cancer disease documented by conventional imaging (example, computed tomography \[CT\], magnetic resonance imaging \[MRI\], or bone scan) and/or next-generation imaging \[NGI\] demonstrating greater than or equal (\>=) 2 distinct extraprostatic sites of metastasis * For participants undergoing Gender-affirming care: No evidence of metastasis by either conventional imaging (example, CT, MRI, or bone scan) and/or NGI is also acceptable * For participants not undergoing gender-affirming care: testosterone levels \> 50 (ng/dL) nanograms per deciliter at screening, except for those who may have received ADT 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 level requirement 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 is related to stable physical limitations (example, wheelchair-bound due to prior spinal 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 this study or wit…