12. All other significant diseases (for example, inflammatory bowel disease, uncontrolled asthma, colitis and pneumonitis), which, in the opinion of the Investigator, might impair the subject's tolerance of trial treatment 13. Any psychiatric condition that would prohibit the understanding or rendering of informed consent 14. Vaccination within 4 weeks of the first dose of avelumab and while on trial is prohibited except for administration of inactivated vaccines 15. Any approved anticancer therapy, including chemotherapy, hormonal therapy or radiotherapy, within 4 weeks prior to initiation of study treatment 16. Major surgical procedure within 28 days prior to treatment or anticipation of need for a major surgical procedure during the course of the study