{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,20]],"date-time":"2026-10-20T15:57:21Z","timestamp":1792511841909,"version":"4.5.0"},"reference-count":28,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,7,1]],"date-time":"2026-07-01T00:00:00Z","timestamp":1782864000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Immunol."],"abstract":"<jats:p>Mismatched-repair\u2013proficient\/microsatellite-stable (pMMR\/MSS) metastatic colorectal cancer (mCRC) is typically refractory to immune checkpoint inhibitors. Early randomized data suggest that adding PD-1 blockade to anti-angiogenic therapy and oxaliplatin-based chemotherapy may improve outcomes, but real-world evidence remains limited. A 62-year-old woman presented with advanced sigmoid colon adenocarcinoma and liver, lung, and nodal metastases (cT4aN2bM1b). Molecular profiling showed KRAS p.G12D and pMMR\/MSS status. First-line treatment with serplulimab, bevacizumab, and XELOX was initiated. After two cycles, carcinoembryonic antigen (CEA) declined from 3458.2 ng\/mL to 1812.84 ng\/mL. Over eight induction cycles, cross-sectional imaging demonstrated sustained regression of hepatic and pulmonary metastases without new lesions, representing a near-complete response. Following six cycles of maintenance therapy with serplulimab, bevacizumab, and capecitabine, restaging CT and endoscopy showed no visible tumor, consistent with a clinical complete response (cCR), accompanied by resolution of abdominal pain. The patient remains progression-free beyond 12 months at last follow-up. This case illustrates the feasibility and potential of combining PD-1 blockade, anti-VEGF therapy, and oxaliplatin-based chemotherapy for pMMR\/MSS mCRC, aligning with efficacy signals from ASTRUM-015 (phase 2 median PFS 17.2 vs 10.7 months; HR 0.60; MSS subgroup 17.2 vs 10.1 months; HR 0.58). Prospective, biomarker-informed trials are warranted to validate patient selection and durability of benefit.<\/jats:p>","DOI":"10.3389\/fimmu.2026.1740803","type":"journal-article","created":{"date-parts":[[2026,7,1]],"date-time":"2026-07-01T13:15:32Z","timestamp":1782911732000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":2,"title":["Clinical complete response to serplulimab plus bevacizumab and chemotherapy in MSS\/KRAS-mutant metastatic sigmoid colon adenocarcinoma: a case report and literature review"],"prefix":"10.3389","volume":"17","author":[{"given":"Qiao","family":"Luo","sequence":"first","affiliation":[{"name":"Department of Oncology, The Affiliated Hospital of Southwest Medical University","place":["Luzhou, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Haiyan","family":"Zhang","sequence":"additional","affiliation":[{"name":"Department of Pathology, The Affiliated Hospital of Southwest 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