Use of Enhertu as a Subsequent Line of Therapy in HER2-Positive Metastatic Castration-Resistant Prostate Adenocarcinoma.

This Phase II clinical trial aims to evaluate the efficacy and safety of Enhertu in HER-2 positive mCRPC who have progressed on prior androgen deprivation therapy and novel hormonal agents, who are either not candidates for or have refused taxane based chemotherapy. Led by Dr. Maneesh Jain at the Washington DC VA, the open label multi center study will include 60 participants treated with Enhertu. Primary endpoints focus on objective response rates, while secondary measures include safety, progression-free survival, overall survival, and quality of life.

Inclusion Criteria:

• Pathologically confirmed adenocarcinoma of the prostate
• Diagnosis of mCRPC
• Documented progression on androgen deprivation and novel hormonal agents, with or without progression on taxane containing regimen
• Ongoing ADT to maintain serum testosterone levels below 50 ng/dL
• Formalin fixed paraffin embedded tumor tissue for HER2 immunohistochemistry
• Life expectancy 6 months
• ECOG 0 or 1
• LVEF at least 50%
• Adequate Blood Clotting function
• Adequate Organ and Bone Marrow function
• Adequate Renal function
• Adequate Hepatic function

Exclusion Criteria:

• History of interstitial lung disease or pneumonitis requiring steroids
• Significant coronary vascular disease
• Previous exposure to HER2 targeted therapy