a clinical study of ifinatamab deruxtecan based treatment combinations or as monotherapy to treat metastatic castrate resistant prostate cancer (mcrpc) (mk-2400-01a/ideate-prostate02)

Conditions: Castration-Resistant Prostatic Cancer; Metastasis

Summary: the purpose of this substudy is to assess the efficacy and safety of ifinatamab deruxtecan (i-dxd), given alone or with other treatments in participants with metastatic castration-resistant prostate cancer (mcrpc). the goals of this study are to learn about: * the safety of the study treatment and if people tolerate it. * a safe dose level of i-dxd that can be used with other treatments. * participant levels of prostate specific antigen (psa) during treatment.

this sub study mk-2400-01a assesses treatments for metastatic castration-resistant prostate cancer (mcrpc). the master screening protocol is mk-2400-u01.

Eligibility criteria:
inclusion criteria: the main inclusion criteria include but are not limited to the following: * has histologically- or cytologically-confirmed adenocarcinoma of the prostate without small cell histology * has prostate cancer progression while on androgen deprivation therapy (adt) (or post bilateral orchiectomy) within 6 months before screening * has current evidence of metastatic disease * has received prior treatment with 1 or 2 androgen receptor pathway inhibitors (arpis) and progressed during or after treatment * participants receiving bone resorptive therapy (including, but not limited to bisphosphonate or denosumab) must have been on stable doses for ≥4 weeks before allocation/randomization * an eastern cooperative oncology group (ecog) performance status of 0 to 1 assessed within 10 days before allocation/randomization * has prior treatment with poly-adp-ribose polymerase inhibitors (parpi) if indicated by local approved regimen or were deemed ineligible to receive parpi by the investigator exclusion criteria: the main exclusion criteria include but are not limited to the following: * history of (non-infectious) interstitial lung disease (ild)/pneumonitis that required steroids, or has current ild/pneumonitis or suspected ild/pneumonitis * clinically severe pulmonary compromise resulting from intercurrent pulmonary illnesses * uncontrolled or significant cardiovascular disease * history of pituitary dysfunction * poorly controlled diabetes mellitus * history or current condition of adrenal insufficiency (eg, addison's disease) * has received prior treatment with taxane-based chemotherapy agent for metastatic castration-resistant prostate cancer (mcrpc). * chronic steroid treatment (dose of \>10 mg daily prednisone equivalent), except for low-dose inhaled steroids (for asthma/chronic obstructive pulmonary disease), topical steroids (for mild skin conditions), or intra-articular steroid injections * received prior radiotherapy within 2 weeks of start of study intervention, or has radiation-related toxicities, requiring corticosteroids * known additional malignancy that is progressing or has required active treatment within the past 3 years * known active central nervous system (cns) metastases and/or carcinomatous meningitis * active autoimmune disease that has required systemic treatment in the past 2 years * history of allogeneic tissue/solid organ transplant