Use of Ligand-Inducible Autologous T Cells Engineered to Target PSCA on Tumor Cells in Selected Advanced Solid Tumors

The goal of this study is to characterize the feasibility, safety, and clinical activity of
PSCA-specific CAR-T cells, BPX-601, administered with rimiducid to subjects with previously
treated, PSCA-positive advanced solid tumors (pancreatic, stomach, or prostate). BPX-601
CAR-T cells are genetically engineered to express a rimiducid-inducible signaling domain
which functions as a molecular switch to enhance activation and proliferation.

Part 1 (Phase 1): Cell dose escalation to identify the maximum dose of BPX-601 T cells
(escalating doses from 1.25 x 10E6 cells/kg up to 5.0 x 10E6 cells/kg to be explored)
administered with rimiducid (fixed single-dose at 0.4 mg/kg).

Inclusion Criteria:

1. Participants with either:

1. Metastatic pancreatic cancer with tumor progression after one prior standard
chemotherapy; or,

2. Metastatic gastric or gastroesophageal junction cancer with tumor progression
after one prior standard chemotherapy; or,

3. Hormone-refractory prostate cancer with tumor progression following treatment
with a taxane-containing regimen and at least one androgen synthesis inhibitor.

2. Tumor with positive PSCA expression as determined by central testing.

3. Participant has a radiographically measurable tumor.

4. Age ≥18 years

5. Participant has a life expectancy >12 weeks and is able to carry out daily life
activities without difficulty (Eastern Cooperative Oncology Group performance status 0
or 1).

6. Participant has adequate venous access for apheresis or agree to use of a central line
for apheresis collection

7. Participant does not have significant side effects from previous anticancer treatment.

8. Participant has adequate organ and blood cell counts.

9. Sexually active participants must use medically acceptable methods of contraception
for at least 1 year after study treatment.

Exclusion Criteria:

1. Pancreatic cancer with islet cell neoplasms or symptomatic coagulopathy.

2. Gastric/GEJ with:

1. Abnormal kidney function

2. Non-healing wound, peptic ulcer, or bone fracture within 4 weeks of study
treatment

3. History of gastric perforation and/or fistula within 6 months of study treatment

4. Bowel obstruction, history or presence of other inflammatory enteropathy
including Crohn's disease, ulcerative colitis, or chronic diarrhea

5. Chronic treatment with non-steroidal anti-inflammatory agents or anti-platelet
agents

6. Significant bleeding disorder

7. Symptomatic coagulopathy

3. Prostate cancer with unstable bone lesions or symptomatic coagulopathy.

4. Participant has a history of major surgery or treatment with other cancer therapy
within 2-4 weeks before study treatment.

5. Participant has an untreated brain tumor.

6. Current severe, uncontrolled systemic disease including an ongoing, active infection
requiring treatment with antibiotics within 2 weeks before study treatment.

7. History of clinically significant heart problems.

8. Participant is currently pregnant or breastfeeding.

9. Participant requires chronic, systemic steroid therapy.

10. Participant has an active, autoimmune disease that requires immunosuppressive therapy.
Exceptions are vitiligo, type I diabetes, certain cases of hypothyroidism and
psoriasis, or Hashimoto's thyroiditis on a stable dose of thyroid replacement therapy

11. Participant is positive for Hepatitis B, Hepatitis C, HIV, syphilis, West Nile virus,
or Chagas disease.