Due to a Dose Limiting Toxicity.

The purpose of this study is to evaluate the safety and activity of BPX-601 CAR-T cells in participants with previously treated advanced solid tumors (prostate) expressing high levels of prostate stem cell antigen (PSCA). Participants' T cells are modified to recognize and target the PSCA tumor marker on cancer cells.

Former Sponsor Bellicum Pharmaceuticals

Study ended prior to the start of Phase 2

Inclusion Criteria:

• Metastatic castration-resistant prostate cancer (mCRPC), with progressive disease per PCWG3 criteria during or following the direct prior line of therapy.
• Measurable disease per RECIST v1.1 at baseline; subjects with mCRPC with bone only metastases must have measurable PSA.
• Age ≥18 years.
• Life expectancy > 12 weeks.
• ECOG 0-1
• Adequate organ function.

Exclusion Criteria:

• Prostate cancer with unstable bone lesions or symptomatic/untreated coagulopathy, or history of > Grade 2 hematuria within the previous 6 months.
• Prior CAR T cell or other genetically-modified T cell therapy. Prior treatment with an immune-based therapy for the treatment of prostate cancer, including cancer vaccine therapies are allowable.
• Symptomatic, untreated, or actively progressing central nervous system metastases.
• Impaired cardiac function or clinically significant cardiac disease.
• Pregnant or breastfeeding.
• Participant requires chronic, systemic steroid therapy.
• Severe intercurrent infection.
• Known HIV positivity.