Pruritus can be managed with topical or systemic benadryl. Significant local in flammation leading to severe pain may be treated with oral analgesics. Local ulceration should be managed with local wound care, with or without antibiotics, and should be evaluated on a case-by- case basis. 4.2.3 Pembrolizumab (KEYTRUDA®, MK-3475) Pembrolizumab is a humanized monocl onal Ab. Subjects should be closely monitored for potential adverse reactions during antibody infusion and potential adverse even ts throughout the study. Unexpected Grade 3 or greater laboratory abnormalities should be repeated within 24-72 hours if clin ically indicated and mon itored as necessary to determine if event meets toxicity criteria. 4.2.3.1 Infusion Reactions Pembrolizumab infusion reactions may consist of fever, chills/rigor, nausea, pruritus, angioedema, hypotension, head ache, bronchospasm, urticaria, rash, vomiting, myalgia, dizziness or hyperten sion. Severe reactions may include acute respiratory distress syndrome, myocardial infarction, ventricular fibrillation, and cardiogenic shock. Patie nts should be closely monitored for such reactions. Guidelines for patients who experience an infusion related or allergic reaction during or after infusion with pembrolizumab are shown below. Phase 2 Study of GVAX (with CY) and pembrolizum ab in MMR-p advanced colorectal cancer J16154/Version 5 / January 17, 2018 23Table 2: Guidance on Infusion and Hypersensitivity Reactions NCI CTCAE Grade Treatment Premedication at subsequent dosing Grade 1 Mild reaction; infusion interruption not indicated; intervention not indicated Increase monitoring of vital signs as medically indicated until the subject is deemed medically stable in the opinion of the investigator. None Grade 2 Requires infusion interruption but responds promptly to symptomatic treatment (e.g., antihistamines, NSAIDS, narcotics, IV fluids); prophylactic medications indicated for < =24 hrs Stop Infusion and monitor symptoms. Additional appropriate medical therapy may include but is not limited to: IV fluids Antihistamines NSAIDS Acetaminophen Narcotics Increase monitoring of vital signs as medically indicated until the subject is deemed medically stable in the opinion of the investigator. If symptoms resolve within one hour of stopping drug infusion, the infusion may be restarted at 50% of the original infusion rate (e.g., from 100 mL/hr to 50 mL/hr). Otherwise dosing will be held until symptoms resolve and the subject should be premedicated for the next scheduled dose. Subjects who develop Grade 2 toxicity despite adequate premedication should be permanently discontinued from further trial treatment administration.Subject may be premedicated 1.5h (± 30 minutes) prior to infusion of pembrolizumab (MK-3475) with: Diphenhydramine 50 mg po (or equivalent dose of antihistamine). Acetaminophen 500-1000 mg po (or equivalent dose of antipyretic). Grades 3 or 4 Grade 3: Prolonged (i.e., not rapidly responsive to symptomatic medication and/or brief interrupti on of infusion); recurrence of symptoms following initial improvement; hospitalization indicated for other clinical sequelae (e.g., renal impairment, pulmonary infiltrates) Grade 4: Life-threatening; pressor or ventilatory support indicated Stop Infusion. Additional appropriate medical therapy may include but is not limited to: IV fluids Antihistamines NSAIDS Acetaminophen Narcotics Oxygen Pressors Corticosteroids Epinephrine Increase monitoring of vital signs as medically indicated until the subject is deemed medically stable in the opinion of the investigator. Hospitalization may be indicated.