Additional Exclusion Criteria for Selected Tumor Types (i). CRC: None (ii). OvC: None (iii). SCLC: Mixed histology SCLC malignancies (iv). TNBC: None (v). AML: a. Planned/anticipated HSCT (autologous or allogeneic, with any degree of match donor); acute promyelocytic leukemia (APL; M3 or any morphologic and molecular variants, inclusive); history or current diagnosis of CNS leukemia b. Relapsed (Second line) patients; Note: Patients who received any chemotherapy (“3 + 7” or similar chemotherapy regiman) for 1 - 2 cycles during initial induction therapy SELLAS Life Sciences Group Galinpepimut -S Protocol : SLS17 -201/MK3475 -770 Protocol v1.1 (Amendment 1.0) 12 April 2019 Page 129 in the first-line setting and subsequently immediately switched to HMAs are not excluded. 4.2. Withdrawal of Patient s from the Study The duration of the study is defined for each patient as the date signed written informed consent is provided through the end-of-treatment visit, which can be up to a maximum of 111 weeks after enrollment, or a total of 115 weeks inclusive of screening. All patients will then be followed for primary, secondary, and exploratory endpoints (including PFS and OS), unless they die or formally withdraw their consent for survival follow -up. Withdrawal of consent must be patient initiated. This applies either if the patient is declaring that they no longer wish to receive study treatment or attend on -treatment study visits or that they will not allow study investigators to make any further efforts to follow them off-treatment for study outcomes. 4.2.1. Reasons for Withdrawal /Discontinuation Discontinuation of study treatment does not represent withdrawal from the study. Patients may voluntarily withdraw from the study at any time and for any reason without prejudice to their future medical care by the investigator or at the study site. The investigator may withdraw a patient if it is in the best interest of the patient. The Sponsor also reserves the right to discontinue the study at any time for either clinical, administrative, or business reasons, and to discontinue participation by an individual investigator or site for poor enrollment or noncompliance. Patients may be removed from study treatment, from on-treatment study assessments, or from off-treatment study assessments but continue to be monitored in the study for the following reasons: • Recurrent Grade 2 pneumonitis SELLAS Life Sciences Group Galinpepimut -S Protocol : SLS17 -201/MK3475 -770 Protocol v1.1 (Amendment 1.0) 12 April 2019 Page 130 • Patient was erroneously admitted into the study or does not meet entry criteria • Patient experiences a serious or intolerable AE o r clinically significant laboratory abnormality that, in the opinion of the investigator, would affect the ability of the patient to continue on the clinical study • Patient has progressive disease • Patient voluntarily decides to withdraw • Patient is lost to follow-up • Patient requires treatment with any prohibited medication outlined in the exclusion criteria and/or Section 5.6 other than the use of appropriate medications for the treatment of AEs under the direction of the investigator • Patient is noncompliant with the study procedures and scheduled assessments • Patient develops an intercurrent disease or medical condition that, in the opinion of the investigator, would affect the ability of the patient to continue on the clinical study. Discontinuation of treatment may be considered for patients who have attained a confirmed CR (either solid tumors or AML, using the corresponding response definitions), as follows: Such patients would have attained CR after having been treated for at least 10 cycles of galinpepimut-S, i.e., at least 30 weeks:2 cycles of galinpepimut-S monotherapy (6 weeks) followed by 9 cycles of pembrolizumab (an additional 24 weeks). Such patients in CR should also receive 2-additional cycles of the combination (2 doses of pembrolizumab and galinpepimut-S [until Week 36]) beyond the date when the initial CR was declared , so that at least 12 of the total 16 (75%) planned doses of galinpepimut-S would have been administered. At that time, 12 out of a planned total of 36 treatments (2 years) with SELLAS Life Sciences Group Galinpepimut -S Protocol : SLS17 -201/MK3475 -770 Protocol v1.1 (Amendment 1.0) 12 April 2019 Page 131 pembrolizumab (corresponding to approximately 33% of the total planned pembrolizumab treatments). 4.2.2. Handling of Withdrawals If a patient discontinues study treatment but remains on study, every effort should be made to continue the patient’s assessments according to the schedule of assessments (Section ) through the end of the study. For patients who withdraw from the study, procedures and assessments for the end-of-treatment (EOT) visit (Section 6.1.3) should be performed at the time of discontinuation of treatment or as soon as possible thereafter (unless the patient withdraws consent to do so). A follow-up assessment performing end of treatment (EOT) procedures should be undertaken 4 weeks after discontinuation of study treatment. If a patient fails to return for scheduled visits, a documented effort must be made to determine the reason. If the patient cannot be reached by telephone, a certified letter should be sent to the patient (or the patient’s legally authorized representative, if appropriate) requesting contact with the investigator. This information should be documented in the study records. Before enrollment into the study, the investigator or designee must explain to each patient that for evaluation of study results, the patient’s protected health information obtained during the study may be shared with the study sponsor, regulatory agencies, and IRB/independent ethics committee (IEC). It is the investigator’s (or designee’s) responsibility to obtain written permission to use protected health information per country-specific regulations, such as the Health Insurance Portability and Accountability Act (HIPAA) in the US, from each patient, or if appropriate, the patient’s legally authorized representative. If permission to use protected health information is withdrawn, it is the investigator’s responsibility to obtain a written request, to ensure that no further data will be collected from the patient, and the patient will be removed from the study. SELLAS Life Sciences Group Galinpepimut -S Protocol : SLS17 -201/MK3475 -770 Protocol v1.1 (Amendment 1.0) 12 April 2019 Page 132 Upon occurrence of a serious or intolerable AEs, the investigator will confer with the Sponsor. It is vital to obtain follow -up data on any patient withdrawn because of an AE or serious AE (SAE). In every case, efforts must be made to undertake protocol-specified, safety follow-up procedures. Notification of early patient discontinuation from the study and the reason for discontinuation will be made to the sponsor, and will be clearly documented on the appropriate electronic case report form (eCRF). 4.2.3.