PET/MR Assessment of Sipuleucel T Treatment for Metastatic Castration Resistant Prostate Cancer

Recent studies of treatments of prostate cancer through stimulation of adaptive immune
response have indicated the linear measurements by computed tomography (CT) and nuclear
scans used to assess tumor response by Response Evaluation Criteria in Solid Tumors (RECIST)
were inadequate and the value of progression-free survival (PFS) as a predictive surrogate
endpoint of survival was lost.

The objective of this study is to provide an initial evaluation of the utility of PET/MR
imaging measures for the prediction of immunological response to SipT therapy. Investigators
expect to identify an"imaging-signature" of response to SipT based on changes in metabolism,
perfusion, oxygenation and cellularity of metastasis and its correlation with immunological
and clinical response. This approach will help elucidate the mechanism of activity and
dynamics of immune antitumor responses to SipT in vivo and to identify new parameters of
tumor response and predictive value than current RECIST and PFS standards.

Inclusion Criteria:

- Men ≥ 18 years of age

- History of prostate cancer treated with androgen deprivation

- Serum Testosterone levels <50 ng/mL

- Established asymptomatic or minimally symptomatic metastasis

- Eastern Cooperative Oncology Group (ECOG) performance status≤2

- Accept the terms of the imaging modalities and performance at pre-established time
points as described in the protocol and consent

- Accept the terms for immune-monitoring blood drawing and performance at
pre-established time points as described in the protocol and consent

- Patients that are on steroids (prednisone up to 10mg daily or hydrocortisone 20 mg
daily) alone or in combination with Zytega or ketoconazole prior to enrollment are
eligible

- Patients that are on steroids for an underlying chronic condition are eligible.
(prednisone up to 10 mg daily, dexamethasone <2 mg daily or fludrocortisone 0.1 mg
daily orally)

Exclusion Criteria:

- Chemotherapy or radiation therapy treatment within 21 days of Sipuleucel-T

- ECOG performance status >2

- Prior treatment with Sipuleucel-T

- Patients with a history of another primary malignancy within the last 2 years that
was not curatively treated, excluding basal or squamous cell carcinoma of the skin

- Patients with known positivity for human immunodeficiency virus (HIV) or hepatitis C;
baseline testing for HIV and hepatitis C is not required

- Patients with any significant history of non-compliance to medical regimens or with
inability to grant a reliable informed consent

- Active spinal cord compression.