Testing the Combination of Two Experimental Drugs MK-3475 (Pembrolizumab) and Interferon-gamma for the Treatment of Mycosis Fungoides and Sézary Syndrome and Advanced Synovial Sarcoma

Inclusion Criteria

• MYCOSIS FUNGOIDES /SEZARY SYNDROME (TREATMENT GROUP I)
• Stage IB-IVB Mycosis Fungoides or Sezary syndrome, and who have relapsed, are refractory, or progressed after at least one standard systemic therapy; maximal stage since diagnosis will determine eligibility; current disease stage at time of entry will also be documented but will not be used for eligibility
• Subjects must have the following minimum wash-out from previous treatments and without treatment between documentation of relapse/progression and enrollment:
• >= 2 weeks for local radiation therapy
• >= 8 weeks for low dose (12 Gy or less) Total Skin Electron Beam Therapy (TSEBT)
• >= 4 weeks for systemic cytotoxic anticancer agents, anticancer investigational agents that are not defined as immunotherapy, or for tumor-targeting monoclonal antibodies (mAbs) with the exception of alemtuzumab for which the washout is at least 16 weeks
• >= 15 weeks for anti-CD137 or anti-CTLA-4 (including ipilimumab or any other antibody or drug specifically targeting T-cell co-stimulation or checkpoint pathways)
• >= 2 weeks from resolution (i.e., = 2 weeks for retinoids, interferons, vorinostat, romidepsin and denileukin diftitox
• >= 4 weeks for doses of systemic corticosteroids greater than 10 mg/day of prednisone or equivalent; patients who are on physiologic doses of corticosteroids (prednisone equivalent 10 mg/day or less) may participate, however, they must be on a stable dose for at least 4 weeks before enrollment; patients who are on low or moderate potency topical corticosteroids may participate if they are on a stable dose for at least 4 weeks before enrollment; inhaled corticosteroids are acceptable; local injections of corticosteroids are acceptable; all corticosteroids will be reported as concomitant medications
• >= 2 weeks for phototherapy
• >= 1 week for topical therapy (including retinoid, nitrogen mustard, or imiquimod)
• Patients with prior treatment with IFN-gamma will be eligible, if they previously tolerated IFN-gamma, however patients must be off of IFN-gamma for at least three weeks before initiation of therapy on this trial
• Age >= 18 years
• Have measurable disease based on modified severity-weighted assessment tool (mSWAT); tumor lesions situated in a previously irradiated area are considered measurable if progression has been demonstrated in such lesions
• Have a performance status of 0 or 1 on the Eastern Cooperative Oncology Group (ECOG) performance scale
• Absolute neutrophil count (ANC) >= 1500/mcL (performed within 10 days of treatment initiation)
• Platelets >= 100000/mcL (performed within 10 days of treatment initiation)
• Hemoglobin >= 9 g/dL or >= 5.6 mmol/L (performed within 10 days of treatment initiation)
• Creatinine = = 60 mL/min for patient with creatinine levels > 1.5 x institutional ULN (performed within 10 days of treatment initiation)
• Creatinine clearance (CrCl) should be calculated per institutional standard; glomerular filtration rate (GFR) can also be used in place of creatinine or CrCl
• Total bilirubin = 1.5 x ULN (performed within 10 days of treatment initiation)
• Aspartate aminotransferase (AST) (serum glutamic-oxaloacetic transaminase [SGOT]) and alanine aminotransferase (ALT) (serum glutamate pyruvate transaminase [SGPT]) = = 12 years; patients >= 18 years of age must be able and willing to provide informed consent; patients under 18 years of age must have a parent or guardian willing and able to provide consent
• Eastern Cooperative Oncology Group (ECOG) performance status of 0, 1 or 2
• Life expectancy greater than or equal to (>=) 12 weeks
• Measurable disease, as defined by Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1
• Tumor safely accessible for biopsy
• Adequate hematologic and end organ function
• For female participants of childbearing potential and male participants with partners of childbearing potential, agreement (by participant and/or partner) to use highly effectiv