Study halted prematurely and will not resume; participants are no longer being examined or receiving intervention

This is an imaging trial, to develop h11B6 as a therapeutic radiopharmaceutical for men with mCRPC.

This imaging study will be conducted to confirm the safety and estimate the mass amount of antibody h11B6, and confirm in vivo tumor targeting of the antibody, using Indium-111 (111In) radiolabeled h11B6 in subjects with advanced prostate cancer. This study will also provide the dosimetric information crucial for Phase 1 therapy.

It is the intent to develop h11B6 as a therapeutic radiopharmaceutical for men with mCRPC. This Phase 0 study will be conducted to confirm the safety, estimate the mass amount, and confirm in vivo tumor targeting of the antibody. This study will use Indium-111 (111In) radiolabeled h11B6 in subjects with mCRPC to image known sites of disease and identify a favorable mass amount of antibody for satisfactory tumor targeting with minimal/no accumulation off-target. In cohort 1, In-111 labeled h11B6 will remain fixed at 2 mg, and additional h11B6 will be added in 2 sub-cohorts (8 mg and 18 mg respectively); up to 6 patients may be entered into a sub-cohort. Additional patients (up to 6) will be studied once the most favorable mass and imaging time point have been established, to establish targeting of antibody to known disease.

This study will provide the dosimetric information crucial for Phase 1 therapy.

Inclusion Criteria:

• Subjects with mCRPC will be eligible if they meet the following criteria:
• Eastern Cooperative Oncology Group (ECOG) ≤ 1
• Histologically or cytologically confirmed adenocarcinoma of the prostate
• Castrate levels of testosterone (<50 ng/dL [1.74 nmol/L])
• Metastatic disease documented by imaging
• Documented progressive mCRPC with androgen involvement as defined by - Prostate Cancer Working Group 3
• Acceptable laboratory parameters
• At least 28 days since administration of any therapeutic radioactive isotope
• Able to tolerate the conditions required to perform imaging studies (e.g., lying flat for at least 1 hour).

Exclusion Criteria:

• Known hypersensitivity to proteins, or other allergic diathesis that, in the opinion of the investigator, makes an immune response to humanized antibody likely
• Radiotherapy or immunotherapy within 30 days, or single fraction of palliative radiotherapy within 14 days of administration of study agent
• Any condition that, in the opinion of the Investigator, would impair the subject's ability to comply with study procedures and required study visits
• Active, symptomatic, or untreated brain metastases.

The study is being carried out in prostate cancer which afflicts only men.