Age ≥ 18 years (Age ≥ 12 years for patients with bone sarcomas). 
Histologically confirmed diagnosis of unresectable, recurrent, and/or metastatic high grade soft-tissue or bone sarcoma of one of the following subtypes: soft tissue sarcomas (leiomyosarcoma, poorly differentiated/de-differentiated liposarcoma, high grade pleomorphic undifferentiated sarcoma/MFH and synovial sarcoma), and bone sarcomas (Ewing sarcoma, osteosarcoma, and chondrosarcoma [de-differentiated or mesenchymal]). 
ECOG Performance Status of 0 or 1. 
At least one site of measurable disease on CT/MRI scans as defined by RECIST 1.1. Baseline imaging must be performed within 30 days of dosing. 
At least one site of accessible disease for pre- and post-treatment core biopsies for at least 20 patients per arm on the expansion cohorts. 
Patients may have received 1-3 prior systemic therapies in the metastatic setting. 
Adequate organ function within 14 days of dosing 
Must be willing to provide and have available archival tissue for PD-L1 testing. 
Written, voluntary informed consent. 
Fertile men and women of childbearing potential must agree to use an effective method of birth control from providing signed consent and for 120 days after last study drug administration. Women of childbearing potential include pre-menopausal women and women within the first 2 years of the onset of menopause. Women of childbearing potential must have a negative pregnancy test ≤ 72 hours prior to Day 1 of study. 
Effective methods of birth control include: surgically sterile, barrier device (condom, diaphragm), contraceptive coil, intrauterine device (IUD), and abstinence. 
Life expectancy of >12 weeks. 
Patients with central nervous system disease are eligible for enrollment if they have received prior radiotherapy or surgery to sites of CNS metastatic disease and are without evidence of clinical progression for at least 4 weeks prior to screening, have no evidence of new or enlarging brain metastases, and are off steroids for at least 7 days before first dose of pembrolizumab. 

NCT02301039_inc_T1
Person
Age
NCT02301039_inc_T2
Value
≥ 18 years
NCT02301039_inc_T3
Person
Age
NCT02301039_inc_T4
Value
≥ 12 years
NCT02301039_inc_T5
Condition
bone sarcomas
NCT02301039_inc_T6
Procedure
Histologically
NCT02301039_inc_T7
Value
confirmed
NCT02301039_inc_T8
Condition
soft-tissue sarcoma
NCT02301039_inc_T9
Qualifier
high grade
NCT02301039_inc_T10
Qualifier
metastatic
NCT02301039_inc_T11
Temporal
recurrent
NCT02301039_inc_T12
Qualifier
unresectable
NCT02301039_inc_T13
Condition
bone sarcoma
NCT02301039_inc_T14
Scope
soft-tissue or bone sarcoma
NCT02301039_inc_T15
Scope
unresectable, recurrent, and/or metastatic high grade
NCT02301039_inc_T16
Condition
soft tissue sarcomas
NCT02301039_inc_T17
Condition
leiomyosarcoma
NCT02301039_inc_T18
Condition
liposarcoma
NCT02301039_inc_T19
Qualifier
poorly differentiated
NCT02301039_inc_T20
Qualifier
de-differentiated
NCT02301039_inc_T21
Scope
poorly differentiated/de-differentiated
NCT02301039_inc_T22
Condition
sarcoma
NCT02301039_inc_T23
Qualifier
undifferentiated
NCT02301039_inc_T24
Qualifier
pleomorphic
NCT02301039_inc_T25
Qualifier
high grade
NCT02301039_inc_T26
Condition
MFH
NCT02301039_inc_T27
Condition
synovial sarcoma
NCT02301039_inc_T28
Scope
sarcoma/MFH and synovial sarcoma
NCT02301039_inc_T29
Scope
high grade pleomorphic undifferentiated
NCT02301039_inc_T30
Condition
bone sarcomas
NCT02301039_inc_T31
Condition
Ewing sarcoma
NCT02301039_inc_T32
Condition
osteosarcoma
NCT02301039_inc_T33
Condition
chondrosarcoma
NCT02301039_inc_T34
Qualifier
de-differentiated
NCT02301039_inc_T35
Qualifier
mesenchymal
NCT02301039_inc_T36
Scope
de-differentiated or mesenchymal
NCT02301039_inc_T37
Scope
(Ewing sarcoma, osteosarcoma, and chondrosarcoma [de-differentiated or mesenchymal])
NCT02301039_inc_T38
Scope
leiomyosarcoma, poorly differentiated/de-differentiated liposarcoma, high grade pleomorphic undifferentiated sarcoma/MFH and synovial sarcoma
NCT02301039_inc_T40
Scope
soft tissue sarcomas (leiomyosarcoma, poorly differentiated/de-differentiated liposarcoma, high grade pleomorphic undifferentiated sarcoma/MFH and synovial sarcoma), and bone sarcomas (Ewing sarcoma, osteosarcoma, and chondrosarcoma [de-differentiated or mesenchymal])
NCT02301039_inc_T41
Measurement
ECOG Performance Status
NCT02301039_inc_T42
Value
0 or 1
NCT02301039_inc_T43
Condition
measurable disease
NCT02301039_inc_T44
Procedure
CT scans
NCT02301039_inc_T45
Procedure
MRI scans
NCT02301039_inc_T46
Scope
CT/MRI scans
NCT02301039_inc_T47
Procedure
imaging
NCT02301039_inc_T48
Temporal
Baseline
NCT02301039_inc_T49
Temporal
within 30 days of dosing
NCT02301039_inc_T50
Reference_point
dosing
NCT02301039_inc_T52
Multiplier
1-3
NCT02301039_inc_T53
Temporal
prior
NCT02301039_inc_T54
Procedure
systemic therapies
NCT02301039_inc_T55
Qualifier
metastatic setting
NCT02301039_inc_T56
Condition
Adequate organ function
NCT02301039_inc_T57
Temporal
within 14 days of dosing
NCT02301039_inc_T58
Reference_point
dosing
NCT02301039_inc_T62
Person
women
NCT02301039_inc_T63
Person
men
NCT02301039_inc_T64
Condition
childbearing potential
NCT02301039_inc_T65
Procedure
birth control
NCT02301039_inc_T66
Temporal
from providing signed consent
NCT02301039_inc_T67
Reference_point
providing signed consent
NCT02301039_inc_T68
Temporal
for 120 days after last study drug administration
NCT02301039_inc_T69
Reference_point
last study drug administration
NCT02301039_inc_T70
Scope
men and women of childbearing potential
NCT02301039_inc_T73
Person
Women
NCT02301039_inc_T74
Condition
childbearing potential
NCT02301039_inc_T75
Condition
pre-menopausal
NCT02301039_inc_T76
Person
women
NCT02301039_inc_T77
Person
women
NCT02301039_inc_T78
Temporal
within the first 2 years of the onset of menopause
NCT02301039_inc_T79
Reference_point
the onset of menopause
NCT02301039_inc_T80
Condition
childbearing potential
NCT02301039_inc_T81
Person
Women
NCT02301039_inc_T82
Measurement
pregnancy test
NCT02301039_inc_T83
Value
negative
NCT02301039_inc_T84
Temporal
≤ 72 hours prior to Day 1
NCT02301039_inc_T85
Reference_point
Day 1
NCT02301039_inc_T86
Scope
Women of childbearing potential
NCT02301039_inc_T87
Procedure
birth control
NCT02301039_inc_T88
Condition
surgically sterile
NCT02301039_inc_T89
Device
barrier device
NCT02301039_inc_T90
Device
condom
NCT02301039_inc_T91
Device
diaphragm
NCT02301039_inc_T92
Scope
condom, diaphragm
NCT02301039_inc_T93
Device
contraceptive coil
NCT02301039_inc_T94
Device
intrauterine device (IUD)
NCT02301039_inc_T95
Procedure
abstinence
NCT02301039_inc_T97
Scope
surgically sterile, barrier device (condom, diaphragm), contraceptive coil, intrauterine device (IUD), and abstinence
NCT02301039_inc_T98
Observation
Life expectancy
NCT02301039_inc_T99
Value
>12 weeks
NCT02301039_inc_T100
Condition
central nervous system disease
NCT02301039_inc_T101
Procedure
radiotherapy
NCT02301039_inc_T102
Procedure
surgery
NCT02301039_inc_T103
Condition
CNS metastatic disease
NCT02301039_inc_T104
Condition
clinical progression
NCT02301039_inc_T105
Negation
without
NCT02301039_inc_T106
Temporal
for at least 4 weeks prior to screening
NCT02301039_inc_T107
Reference_point
screening
NCT02301039_inc_T108
Condition
brain metastases
NCT02301039_inc_T109
Qualifier
enlarging
NCT02301039_inc_T110
Qualifier
new
NCT02301039_inc_T111
Scope
new or enlarging
NCT02301039_inc_T112
Negation
no
NCT02301039_inc_T113
Drug
steroids
NCT02301039_inc_T114
Negation
off
NCT02301039_inc_T115
Temporal
for at least 7 days before first dose of pembrolizumab
NCT02301039_inc_T116
Reference_point
first dose of pembrolizumab
NCT02301039_inc_T117
Drug
pembrolizumab
NCT02301039_inc_T118
Scope
radiotherapy or surgery to sites of CNS metastatic disease and are without evidence of clinical progression for at least 4 weeks prior to screening, have no evidence of new or enlarging brain metastases, and are off steroids for at least 7 days before first dose of pembrolizumab