The purpose of the study is to determine if the intermittent use of androgen-deprivation therapy (ADT) in participants with metastatic castrate-sensitive prostate cancer (mCSPC) who reached a prostate-specific antigen (PSA) level \< 0.2 nanograms/millilitres (ng/mL) after 6 months of treatment with apalutamide and ADT combination therapy provides non-inferior radiographic progression-free survival (rPFS) and a reduced burden of hot flashes measured as 18-month percent change in severity adjusted hot flash score.