A Clinical Study of Ifinatamab Deruxtecan (I-DXd) in People With Metastatic Prostate Cancer (MK-2400-001)

Inclusion Criteria:

The main inclusion criteria include but are not limited to the following:

• Has histologically- or cytologically-confirmed adenocarcinoma of the prostatewithout small cell histology

• Has prostate cancer progression while on androgen deprivation therapy (ADT) (or postbilateral orchiectomy) within 6 months prior to Screening

• Has current evidence of distant metastatic disease (M1 disease) documented by eitherbone lesions on bone scan and/or soft tissue disease by computed tomography (CT)/magnetic resonance imaging (MRI)

• Has received prior treatment with 1 or 2 androgen receptor pathway inhibitors (ARPIs) and progressed during or after at least 8 weeks of treatment

• Has provided tumor tissue from a core or excisional biopsy from soft tissue notpreviously irradiated and obtained after disease progression on the most recentprior therapy

• Has recovered from adverse events (AEs) due to previous anticancer therapies

Exclusion Criteria:

The main exclusion criteria include but are not limited to the following:

• Is unable to swallow tablets/capsules

• Has any of the following indicators of interstitial lung disease (ILD)/pneumonitis:

1. Has any history of ILD/pneumonitis that required steroid use, except for ahistory of radiation pneumonitis that did not require steroids

2. Has current ILD/pneumonitis

3. Has a clinical or radiographic suspicion of ILD for which the diagnosis of ILDcannot be ruled out

• Has clinically severe pulmonary compromise resulting from intercurrent pulmonaryillnesses

• Has uncontrolled or significant cardiovascular disease

• Has received prior treatment with a taxane-based chemotherapy agent for metastaticcastration-resistant prostate cancer (mCRPC)

• Has had prior discontinuation of an antibody drug conjugate (ADC) that consists ofan exatecan derivative (eg, trastuzumab deruxtecan) due to treatment-relatedtoxicities

• Has a "superscan" bone scan