{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,3]],"date-time":"2026-09-03T20:25:41Z","timestamp":1788467141888,"version":"build-2803163510"},"reference-count":30,"publisher":"MJS Publishing, Medical Journals Sweden AB","license":[{"start":{"date-parts":[[2026,5,6]],"date-time":"2026-05-06T00:00:00Z","timestamp":1778025600000},"content-version":"unspecified","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["AO"],"abstract":"<jats:p>Introduction: Immune checkpoint inhibitors can elicit atypical responses such as pseudoprogression (psPD) and mixed responses (MR). We aimed to analyze the occurrence and prognostic impact of atypical responses in metastatic clear-cell renal cell carcinoma (m-ccRCC) patients treated with ipilimumab\/nivolumab.Materials and methods: In this retrospective series of m-ccRCC patients treated with ipilimumab\/nivolumab in first-line, we performed radiographic evaluation using Response Evaluation Criteria in Solid Tumors and iRECIST consensus guidelines and compared both methods.Results: We assessed 258 baseline target lesions in 100 eligible patients. MR occurred in 24% of patients. In 15 patients (62%), the MR evolved to confirmed progressive disease (cPD), while in nine patients (38%), the MR evolved toward a partial response (PR) and was thus a psPD. psPD occurred in 13% of patients: with increase of all lesions in four patients or with MR features in nine patients. psPD patients had the second best time-to-progression (TTP) and cancer-specific survival (CSS), slightly lower compared to TTP and CSS in patients with PR without a phase of psPD and better than TTP and CSS in patients with stable disease as best response. From all patients who presented with PD at first CT evaluation (n = 40), including 17 patients with unconfirmed progressive disease and 23 patients with MR, in 12 (30%) patients this was a psPD and led to a PR.Conclusions: Atypical responses such as psPD and MR occurred in 13 and 24% of m-ccRCC patients treated with ipilimumab\/nivolumab. Patients with psPD had favorable outcomes, while MR in most cases evolved to progression.<\/jats:p>","DOI":"10.2340\/ao.v65.45460","type":"journal-article","created":{"date-parts":[[2026,5,6]],"date-time":"2026-05-06T13:05:58Z","timestamp":1778072758000},"page":"379-388","source":"Crossref","is-referenced-by-count":1,"title":["Incidence and impact of pseudoprogression and mixed responses in metastatic renal cell carcinoma patients treated with ipilimumab\/nivolumab: a retrospective analysis"],"prefix":"10.2340","volume":"65","author":[{"ORCID":"https:\/\/orcid.org\/0009-0000-3086-8626","authenticated-orcid":false,"given":"Aaron","family":"Caeyman","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Giulia","family":"Mammone","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lisa","family":"Kinget","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Marcella","family":"Baldewijns","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Liesbeth","family":"De Wever","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Maarten","family":"Albersen","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Philip R","family":"Debruyne","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Octavie","family":"Demeulenaere","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Edward Scott","family":"McTaggart","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Saurabh","family":"Saraswat","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Charlien","family":"Berghen","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Gert","family":"De Meerleer","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Stefan","family":"Naulaerts","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Abhishek D","family":"Garg","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7427-9102","authenticated-orcid":false,"given":"Benoit","family":"Beuselinck","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1183","published-online":{"date-parts":[[2026,5,6]]},"reference":[{"key":"154450","doi-asserted-by":"crossref","unstructured":"Zhan X, Chen T, Liu Y, Wan H, Liu X, Deng X, et al., Trends in cause of death among patients with renal cell carcinoma in the United States: a SEER-based study. 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