ENVELOPE: enfortumab vedotin in patients with advanced small bowel adenocarcinoma refractory or intolerant to platinum-based therapy—phase II investigator-initiated trial (NCCH2412/MK015)

Background: Small bowel adenocarcinoma (SBA) is a rare cancer with limited treatment strategies beyond first-line platinum-based combination therapy and no established second-line standard. Our recent retrospective study showed that Nectin-4 is frequently highly expressed in SBA and is associated with poorer outcomes, providing a biological rationale for evaluating enfortumab vedotin-a Nectin-4-targeted antibody-drug conjugate. We designed ENVELOPE to evaluate enfortumab vedotin in advanced SBA refractory or intolerant to platinum-based chemotherapy. Trial design: = 27). A prospective translational program requires pretreatment tumor tissue, prespecifies Nectin-4 immunohistochemistry as the exploratory biomarker, and collects on-study biopsies/serial blood at baseline, on treatment, and at progression for multi-omics profiling.