Adjuvant Pembrolizumab After Radiation Therapy for Lung-Intact Malignant Pleural Mesothelioma

Study Groups:

If you are found to be eligible to take part in this study, you will be assigned to 1 of 2
groups. Your doctor will decide which group you are in. Up to 12 participants will be
enrolled in each group.

If you are enrolled in Group A, you will have already received at least 2 cycles of
chemotherapy and possibly lung-sparing surgery. You will then receive radiation therapy to
one side of your chest, or thorax, a technique called "hemithoracic radiation." You will then
receive pembrolizumab.

If you are enrolled in Group B, you may or may not have had chemotherapy or immunotherapy.
You will not have received surgery. You will receive radiation therapy over a course of 1-3
weeks to a region that does not include the entire side of your chest, or thorax. You will
then receive pembrolizumab.

Study Drug Administration:

In both groups, you will receive pembrolizumab by vein over about 30 minutes on Day 1 of each
3-week cycle after radiation therapy, for up to 2 years.

Study Visits:

When you are not receiving radiation, you will have these visits about every 3 weeks while
you receive immunotherapy:

- You will have a physical exam.

- Blood (about 1-2 tablespoons) will be drawn to check your immune system, for side
effects, and to check the status of the disease.

You will have a CT and/or PET scan to check the status of the disease before radiation
therapy, at Cycle 4, and then every 3 cycles thereafter. If the doctor thinks it is needed,
you may have extra imaging.

You will have a PFT to check your lung function at Cycle 7 and then every 6 cycles.

End-of-Study Visit:

When you stop receiving the study drug:

- You will have a physical exam.

- Blood (about 1-2 tablespoons) will be drawn to check your immune system, for side
effects, and to check the status of the disease.

- You will have a PFT to check your lung function.

Length of Study:

You may continue taking the study drug for up to 2 years. You will no longer be able to take
the study drug if the disease gets worse, if intolerable side effects occur, or if you are
unable to follow study directions.

If the disease appears to be getting worse or the tumors appear to be getting larger, you may
still be able to receive the study drug if you and your doctor decide it is in your best
interest. Sometimes the disease appears to get worse but the study drug is actually working.

However, there are risks of continuing to receive the study drug because the disease may
actually be getting worse. You are still at risk for side effects due to the study drug. This
could also delay starting other treatments. The disease may get worse to the point that you
are no longer able to receive other treatments.

If you choose to receive the study drug after the disease gets worse, you will continue to
have study visits as described above. The study doctor will discuss this option with you.

Your participation on the study will be over after the follow-up visits.

Follow Up:

About 30 days after your last dose of study drug, you will have a physical exam.

About every 12 weeks after your last dose of pembrolizumab:

- You will have a physical exam.

- You may have CT or PET scans to check the status of the disease.

- If your doctor thinks it is needed, blood (about 1 tablespoon) may be drawn for routine
tests.

- At Weeks 12 and 24, you will have PFTs performed.

If you are unable to make these visits, you will be contacted by phone to check your health.

Inclusion Criteria:

1. Patients must have a histologic diagnosis of malignant pleural mesothelioma, with
histologic diagnosis from the pleura or relevant lymph node stations, including
mediastinal, hilar, or supraclavicular lymph nodes.

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

3. Be >/= 18 years of age on day of signing informed consent.

4. Have measurable or non-measurable disease per Response Evaluation Criteria in Solid
Tumors (RECIST) 1.1. However, note that patients in Cohort 1 that have undergone an R0
resection will be eligible for the trial.

5. Have a performance status of 0 or 1 on the Eastern Cooperative Oncology Group (ECOG)
Performance Scale.

6. Demonstrate adequate organ function as described, all screening labs should be
performed within 10-15 days of treatment initiation: HEMATOLOGICAL: Absolute
neutrophil count (ANC) >/=1,500 /mcL; Platelets >/= 100,000 / mcL; Hemoglobin >/= 9
g/dL or >/= 5.6 mmol/L without transfusion or erythropoietin (EPO) dependency (within
7 days of assessment); RENAL: Serum creatinine or Measured or calculated creatinine clearance (glomerular filtration rate (GFR) can
also be used in place of creatinine or creatinine clearance (CrCl)) >/=60 mL/min for
subject with creatinine levels > 1.5 X institutional ULN;

7. Inclusion #6 continued--HEPATIC: Serum total bilirubin bilirubin 1.5 ULN; aspartate
aminotransferase (AST) serum glutamic oxaloacetic transaminase (SGOT) and alanine
aminotransferase (ALT) serum glutamic pyruvic transaminase (SGPT) 5 X ULN for subjects with liver metastases; Albumin >/= 2.5 mg/dL; COAGULATION:
International Normalized Ratio (INR) or Prothrombin Time (PT) subject is receiving anticoagulant therapy as long as PT or PTT is within therapeutic
range of intended use of anticoagulants; Activated Partial Thromboplastin Time (aPTT)
is within therapeutic range of intended use of anticoagulants

8. Female subject of childbearing potential should have a negative urine or serum
pregnancy within 72 hours prior to receiving the first dose of study medication. If
the urine test is positive or cannot be confirmed as negative, a serum pregnancy test
will be required.

9. Female subjects of childbearing potential should be willing to use 2 methods of birth
control or be surgically sterile, or abstain from heterosexual activity for the course
of the study through 120 days after the last dose of study medication. Subjects of
childbearing potential are those who have not been surgically sterilized or have not
been free from menses for > 1 year.

10. Male subjects should agree to use an adequate method of contraception starting with
the first dose of study therapy through 120 days after the last dose of study therapy.

11. *Additional Inclusion Criteria - COHORT 1 (Patients Receiving Hemithoracic Radiation
Therapy): *1. Patients must not have evidence of metastatic disease per PET/CT scan.
Mediastinal lymph node involvement is acceptable. *2. Patients will have received at
least 2 cycles of induction chemotherapy with pemetrexed/cisplatin or
pemetrexed/carboplatin. *3. The following pulmonary function tests are required: a.
Forced expiratory volume in 1 second (FEV1)>/=30% of predicted postoperative (ppoFEV1,
as if patient underwent a pneumonectomy) based on the following formula using a
quantitative perfusion scan: Predicted post-resection FEV1=FEV1 x % perfusion to the
uninvolved lung from the quantitative perfusion report. b. Diffusing capacity of the
lungs for carbon monoxide (DLCO)>35% predicted.

12. Continued Additional Inclusion Criteria - COHORT 1: Patients must be assessed to be a
suitable candidate for hemithoracic radiation therapy per the treating radiation
oncologist. If the patient undergoes pleurectomy/decortication, they must initiate
hemithoracic radiation therapy within 4 months of the surgery date. Patients that do
not meet the dose constraints outlined below will be removed from the study prior to
radiation therapy.

13. *Additional Inclusion Criteria - COHORT 2: *1. Patients must be assessed to be a
suitable candidate for radiation therapy by the treating radiation oncologist.
Patients that do not meet the dose constraints outlined below will be removed from the
study prior to radiation therapy. *2. Any prior number of prior therapies, including
prior immunotherapy, is allowed. *3. Patient has received prior treatment with a
platinum-pemetrexed regimen.

Exclusion Criteria:

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

2. Has a diagnosis of immunodeficiency. Note that patients should not receive steroids
during Pembrolizumab administration.

3. Has a known history of active tuberculosis (TB) (Bacillus Tuberculosis)

4. Hypersensitivity to pembrolizumab or any of its excipients.

5. Has had a prior anti-cancer monoclonal antibody (mAb) within 4 weeks prior to study
Day 1 or who has not recovered (i.e., due to agents administered more than 4 weeks earlier.

6. Has had prior chemotherapy, targeted small molecule therapy, or radiation therapy
within 2 weeks prior to study Day 1 and who have not recovered adequately from this
treatment (
7. Has a known additional malignancy that is progressing or requires active treatment.
Patients with a stage I-III cancer that has been cured over two years ago are not
excluded in the study.

8. Has known active central nervous system (CNS) metastases and/or carcinomatous
meningitis. 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, and are not using
steroids for at least 7 days prior to trial treatment. This exception does not include
carcinomatous meningitis which is excluded regardless of clinical stability.

9. Has active autoimmune disease that has required systemic treatment in the past 2 years
(i.e. with use of disease modifying agents, corticosteroids or immunosuppressive
drugs). Replacement therapy (eg. thyroxine, insulin, or physiologic corticosteroid
replacement therapy for adrenal or pituitary insufficiency, etc.) is not considered a
form of systemic treatment.

10. Has a history of (non-infectious) pneumonitis that required steroids or current
pneumonitis.

11. Has an active infection requiring systemic therapy.

12. Has known psychiatric or substance abuse disorders that would interfere with
cooperation with the requirements of the trial.

13. Is pregnant or breastfeeding, or expecting to conceive or father children within the
projected duration of the trial, starting with the pre-screening or screening visit
through 120 days after the last dose of trial treatment.

14. Has a known history of Human Immunodeficiency Virus (HIV) (HIV 1/2 antibodies).

15. Has known active Hepatitis B (e.g., hepatitis B surface antigen (HBsAg) reactive) or
Hepatitis C (e.g., hepatitis C virus (HCV) ribonucleic acid (RNA) [qualitative] is
detected).

16. Has received a live vaccine within 30 days of planned start of study therapy. *Note:
Seasonal influenza vaccines for injection are generally inactivated flu vaccines and
are allowed; however intranasal influenza vaccines (e.g., Flu-Mist®) are live
attenuated vaccines, and are not allowed.

17. Evidence of interstitial lung disease.

18. *Additional Exclusion Criteria - COHORT 1: Patients undergoing an extrapleural
pneumonectomy (EPP). Lung sparing surgeries, such as pleurectomy/decortication, are
acceptable.

19. Additional Exclusion Criteria - COHORT 1: Has received prior therapy with an
anti-PD-1, anti-PD-L1, or anti-PD-L2 agent.

20. Additional Exclusion Criteria - COHORT 2: *1. Patients in which hemithoracic radiation
therapy is planned. *2. Patients who have received EPP for mesothelioma.

21. Additional Exclusion Criteria - Cohorts 1 and 2: 1. Patients with inherited syndromes
associated with hypersensitivity to ionizing radiation, specifically patients with
known history of Ataxia-Telangiectasia, Nijmegen breakage syndrome.