Prolonged response to dual immune checkpoint blockade in patients with advanced solid tumors: a case series

Immunotherapy has substantially changed the landscape of cancer. We present five patients with advanced cancer who had failed standard-of-care therapies, participated in clinical trials with anti-CTLA4/anti-PD1 therapy, and had prolonged progression-free survival (PFS): Pt1: microsatellite stable (MSS) rectal adenocarcinoma (34+ months); Pt2: high grade neuroendocrine carcinoma (68 months); Pt3: MSS colon adenocarcinoma (38+ months); Pt4: deficient mismatch repair (dMMR) prostate adenocarcinoma (68+ months); Pt5: high-grade neuroendocrine carcinoma (69+ months). Grade 3 immune-related adverse events (irAEs; n = 4) were treated successfully, allowing further treatment with the anti-PD1 therapy. Positron-emission tomography (PET)/computed tomography (CT) scans demonstrated complete response in 3 of 4 patients whose CT scans had shown partial response. These cases highlight the exceptional outcomes of selected patients with advanced cancer treated with immunotherapy and exemplify the value of personalized patient monitoring/management of irAEs while assessing response to immunotherapy. Ongoing trials evaluate biomarkers that predict response and toxicity associated with immunotherapy.