5.5. Treatment Compliance Every effort should be made to follow the administration schedule for galinpepimut-S and pembrolizumab. If a patient misses a scheduled administration of either the combination or pembrolizumab alone, the drug(s) should be administered as soon as possible thereafter. If the patient is more than one-half the time interval to the next scheduled administration, the patient should skip that preplanned administration and have the next administration on schedule. The disposition of study treatment received by the site, dispensed and administered to the patient, returned to the sponsor, destroyed, lost, etc. must be recorded in the site’s pharmacy log. 5.6. Prior and Concomitant Therapy Any treatments or therapies other than the study treatment, including biologics; blood products; prescription drugs; over-the-counter medications; and complementary or alternative medications including herbal products /supplements, vitamins, and minerals that the patient is SELLAS Life Sciences Group Galinpepimut -S Protocol : SLS17 -201/MK3475 -770 Protocol v1.1 (Amendment 1.0) 12 April 2019 Page 169 receiving will be documented. Use of all concomitant medications will be recorded in the patient’s source document and eCRF. Any changes in concomitant medicatio ns will also be recorded in the patient’s source document and eCRF within 28 days from such a change. Any concomitant medication deemed necessary for the welfare of the patient during the study may be given at the discretion of the investigator. However, i t is the responsibility of the investigator to ensure that details regarding the medication are recorded in full in the eCRF and to consult with the study medical monitor if prohibited medications are considered necessary. The following medications/treatments are prohibited: • Other investigational agents given within 4 weeks prior to starting study treatment and during the on-treatment portion of the study. • Systemic glucocorticoids for any purpose other than to modulate symptoms from an event of clinical interest of s uspected immunologic etiology. The use of physiologic doses of corticosteroids is allowed, in dosing that does not exceed a total of 10 mg daily of prednisone (or equivalent). If systemic corticosteroids are required for treatment of a co-morbid illness during the study, the investigator should confer with the medical monitor. o Note: Inhaled steroids are allowed for management of asthma. • Immunosuppressive therapies are prohibited throughout the on-treatment portion of the study. • Patie nts must have received their last dose of chemotherapy within 3 months before receiving study treatment. Any concurrent cytotoxic chemotherapy, radiation therapy, hormonal therapy, immunotherapy, biologic therapy, or other systemic therapy for cancer is prohibited during the on-treatment portion of the study. SELLAS Life Sciences Group Galinpepimut -S Protocol : SLS17 -201/MK3475 -770 Protocol v1.1 (Amendment 1.0) 12 April 2019 Page 170 • Radiation therapy o Note: Radiation therapy to a symptomatic solitary lesion or to the brain may be considered on an exceptional case by case basis af ter consultation with sponsor. The patient must have clear measurable disease outside the radiated field. Administration of palliative radiation therapy will be considered clinical progression for the purposes of determining PFS. • Live vaccines within 30 days prior to the first dose of trial treatment and while participating in the trial. Examples of live vaccines include, but are not limited to, the following: measles, mumps, rubella, chicken pox, yellow fever, rabies, BCG, and typhoid (oral) vaccine. Seasonal influenza vaccines for injection are generally killed virus vaccines and are allowed. However, intranasal influenza vaccines (e.g. Flu - Mist®) are live attenuated vaccines, and are not allowed. 5.7.