Avelumab Plus 2nd-generation ADT in African American Subjects With mCRPC

This is a nonrandomized, open-label trial of avelumab in subjects with metastatic
castration-resistant prostate cancer (mCRPC) experiencing PSA or radiographic progression
while receiving 2nd generation ADT (abiraterone / enzalutamide/ apalutamide or darolutamide).
Metastases must be radiographically evident by whole body bone scintigraphy or CT/MRI scan.

Thirteen African American subjects will be enrolled into the initial cohort. If at least one
positive response (PSA decrease by >50% and or radiographic per RECIST 1.1) is found, the
study will be expanded to accrue a total of 27 patients. The trial will be conducted in
accordance with Good Clinical Practices.

Subjects enrolled in the study will receive avelumab 10 mg/kg every 2 weeks (Q2W) and
continue their previously started 2nd generation ADT (abiraterone or enzalutamide).

All subjects will undergo radiographic imaging assessments and PSA assessments to evaluate
response to treatment at regular intervals. On study imaging will be assessed every 12 weeks.
Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 will be adapted per the consensus
guidelines of the Prostate Cancer Clinical Trials Working Group 3 (PCWG3) as described in
Appendix A/B to account for the tumor progression patterns seen in bone metastases in
prostate cancer. PSA will be obtained every 2 weeks with PSA progression assessed per PCWG3.

Adverse events (AEs) will be monitored throughout the trial and graded in severity according
to the guidelines outlined in the National Cancer Institute (NCI) Common Terminology Criteria
for Adverse Events (CTCAE) version 4.03.

Treatment with avelumab will continue until documented confirmed disease progression,
unacceptable AEs, intercurrent illness that prevents further administration of treatment,
Investigator's decision to withdraw the subject, subject discontinuation from the study,
noncompliance with trial treatment or procedure requirements, subject receives 52
administrations of avelumab (approximately 2 years), or administrative reasons requiring the
cessation of treatment.

After the end of treatment, each subject will be followed for 30 days for AE monitoring
(serious AEs will be collected for 90 days after the end of treatment or 30 days after the
end of treatment if the subject initiates new anticancer therapy, whichever is earlier).
Subjects who discontinue treatment for reasons other than disease progression will remain on
study and continue to undergo study-related disease assessments until documented disease
progression, initiation of a new non-study prostate cancer treatment, withdrawal of consent,
or becoming lost to follow-up. All subjects will enter survival follow up, and will be
contacted at their regularly scheduled clinic visit, or by telephone approximately every 6
months, until death or withdrawal of consent or end of study.

Inclusion Criteria:

1. Must be of African descent; Black or African American: A person having origins in any
of the black racial groups of Africa. Terms such as "Haitian" or "Negro" can be used
in addition to "Black or African American."

2. Be willing and able to provide written informed consent for the trial.

3. Be ≥18 years of age on day of signing informed consent.

4. Have histologically or cytologically confirmed adenocarcinoma of the prostate without
small cell histology. Diagnosis must be stated in a pathology report.

5. Have evidence of metastatic disease as determined by CT/MRI scans and/or bone
metastases by whole body bone scintigraphy. (Use MRI if CT is contraindicated, and for
imaging of the brain if clinically indicated).

6. Have documented disease progression within 3 months of screening, as determined by the
Investigator, by means of at least one of the following:

PSA progression as defined by a minimum of two rising PSA levels with an interval of ≥
1 week between each assessment where the PSA value at screening should be ≥ 2 ng/mL.

Radiographic disease progression in soft tissue or bone with or without PSA
progression as determined by Recist 1.1 and/or PCWG3

7. Have ongoing androgen deprivation with serum testosterone < 50 ng/dL (< 2.0 nM). If
the subject is currently being treated with Luteinising Hormone Releasing Hormone
(LHRH) agonists or antagonists (for subjects who have not undergone an orchiectomy).
This treatment must be continued throughout the study.

8. Be receiving and tolerating either abiraterone acetate, enzalutamide, apalutamide or
darolutamide for at least 8 weeks prior to documented disease progression. Note: the
2nd generation ADT that the patient is currently progression on needs to be the first
2nd gen ADT used in the CRPC setting

9. Have a performance status of 0, 1 or 2 on the Eastern Cooperative Oncology Group
(ECOG) Performance Scale (Appendix D).

10. Male subjects of reproductive potential must agree practice abstinence from
heterosexual activity OR use a highly effective method of contraception, starting at
the time of informed consent and continue through 60 days after the last dose of study
therapy (see section 6.1.1.)

11. Demonstrate adequate organ function as defined in Table 1, all screening labs should
be performed within 10 days of treatment initiation.

Exclusion Criteria:

1. Is currently participating and receiving study therapy in a clinical trial, or has
participated in a study of an investigational agent (and received study therapy or
used an investigation device) within 4 weeks of the first dose of study treatment.

2. No more than one line of a 2nd generation ADT (abiraterone acetate /enzalutamide/
apalutamide/darolutamide) for mCRPC is permitted for study entry.

3. Has a diagnosis of immunodeficiency or is receiving systemic steroid therapy or any
other form of immunosuppressive therapy within 7 days prior to the first dose of trial
treatment.

Note: the following are allowed: a. intranasal, inhaled, topical steroids, or local
steroid injection (e.g., intraarticular injection); b. systemic corticosteroids at
physiological doses < 10mg/day of prednisone or equivalent; c. steroids as
premedication for hypersensitivity reactions (e.g., CT scan premedication).

4. Has had a prior anti-cancer monoclonal antibody (mAb) within 4 weeks prior to the
first dose of trial treatment or who has not recovered (i.e., ≤ Grade 1 or at
baseline) from adverse events due to mAbs administered more than 4 weeks earlier.

5. Has had >2 prior systemic chemotherapy agents for mCRPC Note: chemotherapy in the
metastatic hormone sensitive prostate cancer (mHSPC) setting is allowed

6. Prior surgery within 4 weeks of initiating study treatment Note: If subjects received
major surgery, they must have recovered adequately from the toxicity and/or
complications from the intervention prior to the first dose of trial treatment.

7. Has any additional malignancy that has required active treatment in the last 3 years.

Exceptions include: basal cell carcinoma of the skin, squamous cell carcinoma of the
skin, or low-grade Ta or T1 urothelial carcinoma of that bladder that has undergone
potentially curative therapy.

8. Has known active central nervous system (CNS) metastases and/or carcinomatous
meningitis.

Note: Subjects with previously treated brain metastases may participate provided they
are stable (without evidence of progression by imaging for at least four weeks prior
to the first dose of trial treatment and any neurologic symptoms have returned to
baseline), have no evidence of new or enlarging brain metastases. This exception does
not include carcinomatous meningitis which is excluded regardless of clinical
stability.

9. Has an active autoimmune disease that might deteriorate when receiving an
immune-stimulatory agent. Patients with diabetes type I, vitiligo, psoriasis, or hypo-
or hyperthyroid diseases not requiring immunosuppressive treatment are eligible.

10. Has had prior organ transplantation including allogenic stem-cell transplantation.

11. Has an active infection requiring systemic therapy.

12. Has active, clinically significant Human Immunodeficiency Virus (HIV) (HIV 1/2
antibodies). Patients with well controlled HIV will be allowed to be enrolled into the
study.

13. Has Hepatitis B virus (HBV) or hepatitis C virus (HCV) infection at screening
(positive HBV surface antigen or HCV RNA if anti-HCV antibody screening test is
positive).

14. Has received a live vaccine within 4 weeks of first dose of avelumab; live vaccines
are prohibited throughout course of the trial. Inactivated vaccines are allowed.

15. Has known prior severe hypersensitivity to investigational product or component in its
formulations, including known severe hypersensitivity reactions to monoclonal
antibodies (NCI CTCAE v4.3 Grade > 3).

16. Has clinically significant (i.e., active) cardiovascular disease: cerebral vascular
accident/stroke (< 6months prior to enrollment), myocardial infarction (< 6months
prior to enrollment), unstable angina, congestive heart failure (> New York Heart
Association Classification Class II), or serious cardiac ventricular arrhythmia
requiring medication.

17. Persisting toxicity related to prior therapy (NCI CTCAE v. 4.3 Grade > 1); however,
alopecia, sensory neuropathy Grade ≤ 2, or other Grade ≤ 2 not constituting a safety
risk based on investigator's judgment are acceptable.

18. Other severe acute or chronic medical conditions including colitis, inflammatory bowel
disease, immune pneumonitis, pulmonary fibrosis or psychiatric conditions including
recent (within the past year) or active suicidal ideation or behavior; or laboratory
abnormalities that may increase the risk associated with study participation or study
treatment administration or may interfere with the interpretation of study results
and, in the judgment of the investigator, would make the patient inappropriate for
entry into this study.