Sites should be trained prior to scanning the first study participant. Image acquisition guidelines and submission process will be outlined in the Imaging Manual to be provided by the core laboratory. For Part A, images will be collected centrally and may be reviewed by BICR at a l ater date, or at any time during the study per BMS request. For Parts B, C, D and E, images will be collected centrally and reviewed by BICR. 9.1.2 Primary Efficacy Assessments Not applicable. Revised Protocol No.: 04 Date: 31-May-2019 100 Approved 5.0 v Approved 1.0 v Clinical Protocol CA021002 BMS-986226 anti-ICOS 9.1.3 Secondary Efficacy Assessments The secondary efficacy assessments will include the objective response rate (ORR; eg, PR + CR), mDOR, and progression-free survival rate (PFSR) at 24 weeks based on assessment of tumor response using RECIST v1.1 or PCWG3 (prostate cancer only). ORR is defined as the proportion of all treated participants whose best overall response (BOR) is either a CR or PR. BOR is defined as the best re sponse designation over the study as a whole, recorded between the dates of first dose and the date of first objectively documented tumor progression per RECIST v1.1 (or PCWG3) or the date of subsequent therapy, whichever occurs first. CR or PR determinations included in the BOR assessment must be confirmed by a second scan performed no less than 4 weeks after the criteria for response are first met. A Best Overall Response of SD requires a minimum of 49 days on study from the date of first dose to the date of the first imaging assessment. For those particip ants who have surgical resection, only pre-surgi cal tumor assessments will be considered in the determination of BOR. mDOR, computed for all tr eated par ticipants with a BOR of CR or PR, is defined as the time between the date of first response and the date of the first objectively documented disease progression per RECIST v1.1 (or PCWG3) or death, whichever occurs first. PFSR at 24 weeks is defined as the proportion of treated participants remaining progression free and surviving at 24 weeks. The proportion w ill be calculated by the Kaplan-Meier estimate, which takes into account censored data.For prostate cancer, the consensus guidelines of the PCWG3 have been taken into consideration for the determination of radiographic disease progression assessment. All target and non-target sites of disease identified on the baseline assessment should be reassessed with the same imaging modality at subsequent assessments. Bone lesions should be assessed with Tc-99m based bone scans. For prostate cancer di sease progression, at each disease assessment, progressive disease will be determined using the criteria based on PCWG3. Radiographic progression in soft tissue les ions (prostate only) is described in Table 9.1.3-1 . See Appendix 11 (PCWG3) for additional information. Revised Protocol No.: 04 Date: 31-May-2019 101 Approved 5.0 v Approved 1.0 v Clinical Protocol CA021002 BMS-986226 anti-ICOS Table 9.1.3-1: Definition of Radiographic Progression Parameter Progression Date of Progression Soft tissue lesions (target, non- target lesions with CT or MRI)Progression of soft tissue lesions (target, non-target, new lesions with CT or MRI)Date of first unequivocal progression of soft tissue lesion (target, non-target, or new lesions) as per PCWG3 a Bone lesions on radionuclide bone scan per PCWG3At least 2 new lesions on the first post-treatment bone scan, confirmed on the next scan (performed at least 6 weeks later) AND with at least 2 additional lesions as compared to the first post-treatment bone scanDate of first post-treatment scan For scans after the first post-treatment scan, at least 2 new lesions relative to the first post-treatment scan AND confirmed on a subsequent scan (performed at least 6 weeks later)Date of progression is the date of the scan that first documents at least 2 new lesions relative to the first post-treatment scan aRECIST v1.1 criteria are modified for assessing soft tissue lesions per PCWG3. See Appendix 11 .