Anti-PD1 therapy can be highly effective in treating melanoma, but many patients develop resistance. Tumors of patients who progress on single-agent anti-PD1 therapy often have no T-cell infiltrates, said Ari VanderWalde, MD, MPH, West Cancer Center. In some patients, the CTLA-4 checkpoint leaves T cells stuck in the lymph node and unable to infiltrate the tumor. An anti-CTLA-4 agent could allow T cells to infiltrate the tumor, reversing resistance to anti-PD-1 agents. The SWOG1616 trial tested that strategy, comparing combination therapy of ipilimumab, an anti-CTLA-4 agent, plus nivolumab, an anti-PD-1 agent, or ipilimumab alone in 91 patients with advanced melanoma refractory to anti-PD-1 or PD-L1 treatment. Dr. VanderWalde presented SWOG1616 trial results during the Clinical Trials Plenary Session Combination Immunotherapy Trials on Tuesday, April 12, at the American Association for Cancer Research (AACR) Annual Meeting, April 8-13 in New Orleans. The session can be viewed on the virtual platform by registered meeting participants through July 13, 2022. Registration can be done here. Over 19,000 scientists and physicians are registered for this premier cancer conference, with ~80% (~15,200) attending in person and ~20% (~3,800) attending virtually. The AACR has over 50,000 members worldwide.