CHICAGO – Side effects of fatigue and excitability set in among attendees during the fourth day of sessions, as the 50th annual meeting of the American Society of Clinical Oncology (ASCO) continued and immuno-oncology (IO) stole the show as predicted. Melanoma drew special attention, especially ipilimumab (Yervoy, Bristol-Myers Squibb Co.) and Merck & Co. Inc. with its PD-1 inhibitor, but there was plenty more.