Safety and Efficacy of Intratumoral Anti-CTLA4 with Intravenous Anti-PD1

Safety and Efficacy of Intratumoral Anti-CTLA4 with Intravenous Anti-PD1 | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Biological Sciences - Article Safety and Efficacy of Intratumoral Anti-CTLA4 with Intravenous Anti-PD1 Aurelien Marabelle, Lambros TSELIKAS, Sandrine SUSINI, Matthieu TEXIER, and 26 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7394486/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 29 Apr, 2026 Read the published version in Nature → Version 1 posted You are reading this latest preprint version Abstract Intravenous anti-CTLA4 with anti-PD1 provides durable tumor responses but generates high rates of severe immune-related adverse events (irAEs) in cancer patients1-3. As opposed to anti-PD1 antibodies, anti-CTLA4 efficacy and toxicity is dose dependent, which limits its use in many patients and restricts broader application, particularly in localized cancers. Therefore, administering lower doses of anti-CTLA4 but directly into tumors and at high local concentrations could enhance anti-tumor efficacy while minimizing systemic exposure and toxicity. Conversely, stronger activation of tumor infiltrating lymphocytes could increase systemic toxicity in case of cross-reactivity with healthy tissue antigens. To challenge those hypothesis we launched a randomized multicenter Phase 1b NIVIPIT trial (NCT02857569), where 61 patients untreated metastatic melanoma patients were randomly assigned 2:1 to receive intravenous nivolumab (1mg/kg) in combination with either intratumoral (IT) ipilimumab (0.3mg/kg) or intravenous (IV) ipilimumab (3mg/kg). The primary endpoint was met with a significantly lower incidence of grade ≥ 3 irAEs at 6 months in the IT arm vs the IV arm (22.6% vs 57.1%), equivalent to anti-PD1 monotherapy, thereby demonstrating the safety of this approach. The RECIST 1.1 best objective response rate was 65.7% for anti-CTLA4 injected tumor lesions, and 50% for the non-injected lesions demonstrating an increased efficacy upon intratumoral anti-CTLA4 therapy. Baseline tumor immune profiling revealed that, unexpectedly, protumoral activated Tregs and M2 macrophages, were alongside HLA-I & II mediated adaptive T- & B-cells anti-tumor immunity predicting durable clinical benefit regardless of the anti-CTLA4 administration route. Upon anti-CTLA4 + anti-PD1 immunotherapy, intratumoral activated Tregs decrease and tumor-secreted Granzymes increase was found only in patients with durable clinical benefit. Our results provide the rationale for developing intratumoral anti-CTLA4 immunotherapy strategies in oligo-metastatic and earlier-stage cancers to avoid toxicities and suggest that persisting intratumoral regulatory–effector immune interface with high Tregs and M2 macrophages is a pre-requisite for anti-CTLA- 4 + anti-PD1 efficacy. Trial registration: ClinicalTrials.gov Identifier, NCT 02857569 Health sciences/Medical research/Drug development Biological sciences/Cancer/Tumour immunology/Immunosurveillance/Immunoediting Health sciences/Medical research/Translational research Biological sciences/Cancer/Skin cancer/Melanoma Full Text Additional Declarations There is NO Competing Interest. Cite Share Download PDF Status: Published Journal Publication published 29 Apr, 2026 Read the published version in Nature → Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7394486","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Biological Sciences - Article","associatedPublications":[],"authors":[{"id":502611461,"identity":"a450362f-4f37-4eff-b044-ef9dcbbb5c43","order_by":0,"name":"Aurelien 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Portfolio","twitterHandle":"","acdcEnabled":false,"dfaEnabled":false,"editorialSystem":"ejp","reportingPortfolio":"","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"","lastPublishedDoi":"10.21203/rs.3.rs-7394486/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7394486/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eIntravenous anti-CTLA4 with anti-PD1 provides durable tumor responses but generates high rates of severe immune-related adverse events (irAEs) in cancer patients1-3. As opposed to anti-PD1 antibodies, anti-CTLA4 efficacy and toxicity is dose dependent, which limits its use in many patients and restricts broader application, particularly in localized cancers. Therefore, administering lower doses of anti-CTLA4 but directly into tumors and at high local concentrations could enhance anti-tumor efficacy while minimizing systemic exposure and toxicity. Conversely, stronger activation of tumor infiltrating lymphocytes could increase systemic toxicity in case of cross-reactivity with healthy tissue antigens. To challenge those hypothesis we launched a randomized multicenter Phase 1b NIVIPIT trial (NCT02857569), where 61 patients untreated metastatic melanoma patients were randomly assigned 2:1 to receive intravenous nivolumab (1mg/kg) in combination with either intratumoral (IT) ipilimumab (0.3mg/kg) or intravenous (IV) ipilimumab (3mg/kg). The primary endpoint was met with a significantly lower incidence of grade ≥ 3 irAEs at 6 months in the IT arm vs the IV arm (22.6% vs 57.1%), equivalent to anti-PD1 monotherapy, thereby demonstrating the safety of this approach. The RECIST 1.1 best objective response rate was 65.7% for anti-CTLA4 injected tumor lesions, and 50% for the non-injected lesions demonstrating an increased efficacy upon intratumoral anti-CTLA4 therapy. Baseline tumor immune profiling revealed that, unexpectedly, protumoral activated Tregs and M2 macrophages, were alongside HLA-I \u0026amp; II mediated adaptive T- \u0026amp; B-cells anti-tumor immunity predicting durable clinical benefit regardless of the anti-CTLA4 administration route. Upon anti-CTLA4 + anti-PD1 immunotherapy, intratumoral activated Tregs decrease and tumor-secreted Granzymes increase was found only in patients with durable clinical benefit. Our results provide the rationale for developing intratumoral anti-CTLA4 immunotherapy strategies in oligo-metastatic and earlier-stage cancers to avoid toxicities and suggest that persisting intratumoral regulatory–effector immune interface with high Tregs and M2 macrophages is a pre-requisite for anti-CTLA- 4 + anti-PD1 efficacy.\u003c/p\u003e\n\u003cp\u003eTrial registration: ClinicalTrials.gov Identifier, NCT 02857569\u003c/p\u003e","manuscriptTitle":"Safety and Efficacy of Intratumoral Anti-CTLA4 with Intravenous Anti-PD1","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-08-20 11:01:47","doi":"10.21203/rs.3.rs-7394486/v1","editorialEvents":[],"status":"published","journal":{"display":false,"email":"[email protected]","identity":"nature","isNatureJournal":true,"hasQc":false,"allowDirectSubmit":false,"externalIdentity":"nature","sideBox":"Learn more about [Nature](http://www.nature.com/nature/)","snPcode":"","submissionUrl":"","title":"Nature","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"ejp","reportingPortfolio":"Nature","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"81e92958-3fd4-4bf4-87fd-fdee60b5024d","owner":[],"postedDate":"August 20th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[{"id":53391072,"name":"Health sciences/Medical research/Drug development"},{"id":53391073,"name":"Biological sciences/Cancer/Tumour immunology/Immunosurveillance/Immunoediting"},{"id":53391074,"name":"Health sciences/Medical research/Translational research"},{"id":53391075,"name":"Biological sciences/Cancer/Skin cancer/Melanoma"}],"tags":[],"updatedAt":"2026-05-05T09:51:32+00:00","versionOfRecord":{"articleIdentity":"rs-7394486","link":"https://doi.org/10.1038/s41586-026-10341-w","journal":{"identity":"nature","isVorOnly":false,"title":"Nature"},"publishedOn":"2026-04-29 04:00:00","publishedOnDateReadable":"April 29th, 2026"},"versionCreatedAt":"2025-08-20 11:01:47","video":"","vorDoi":"10.1038/s41586-026-10341-w","vorDoiUrl":"https://doi.org/10.1038/s41586-026-10341-w","workflowStages":[]},"version":"v1","identity":"rs-7394486","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7394486","identity":"rs-7394486","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}