biostudies-literatureMeltzer SMinistry of Health and Care Services | Helse Sør-Øst RHF (Southern and Eastern Norway Regional Health Authority)Bristol-Myers SquibbMinistry of Health and Care Services | Helse Sør-Øst RHFKreftforeningenKreftforeningen (Norwegian Cancer Society)2227-2233https://www.ebi.ac.uk/biostudies/studies/S-EPMC9726864biostudies-literatureUnknown127(12)<h4>Background</h4>Immune checkpoint blockade (ICB) results in radiologic tumour response dynamics that differ from chemotherapy efficacy measures and require an early signal of clinical utility.<h4>Methods</h4>Previously untreated, unresectable microsatellite-stable (MSS)/mismatch repair-proficient (pMMR) colorectal cancer (CRC) patients were randomly assigned to the oxaliplatin-based Nordic FLOX regimen (control arm) or repeat sequential two FLOX cycles and two ICB cycles (experimental arm). The radiologic response was assessed every 8 weeks. In this post hoc analysis, we explored early target lesion (TL) dynamics as indicator of ICB responsiveness. Progression-free survival (PFS) was the primary endpoint.<h4>Results</h4>Using a landmark analysis approach, we categorised experimental-arm patients into ≥10% (N = 19) or <10% (N = 16) TL reduction at the first post-baseline response assessment. Median PFS for the groups was 16.0 (95% confidence interval (CI), 12.3-19.7) and 3.9 months (95% CI, 2.3-5.5), respectively, superior and inferior (both P < 0.01) to the median PFS of 9.8 months (95% CI, 4.9-14.7) for control arm patients (N = 31).<h4>Conclusions</h4>Radiologic TL reduction of ≥10% at the first post-baseline response assessment identified patients with ICB-responsive metastatic MSS/pMMR-CRC. This pragmatic measure may be used to monitor patients in investigational ICB schedules, enabling early treatment adaptation for unresponsive cases.<h4>Trial registration</h4>ClinicalTrials.gov number, NCT03388190 (02/01/2018).British journal of cancerEarly radiologic signal of responsiveness to immune checkpoint blockade in microsatellite-stable/mismatch repair-proficient metastatic colorectal cancer.PMC972686418054215613Negard AFlatmark KHamre HMHofsli EGuren MGSorbye HMeltzer SKersten CBakke KMRee AHfalseEarly radiologic signal of responsiveness to immune checkpoint blockade in microsatellite-stable/mismatch repair-proficient metastatic colorectal cancer.<h4>Background</h4>Immune checkpoint blockade (ICB) results in radiologic tumour response dynamics that differ from chemotherapy efficacy measures and require an early signal of clinical utility.<h4>Methods</h4>Previously untreated, unresectable microsatellite-stable (MSS)/mismatch repair-proficient (pMMR) colorectal cancer (CRC) patients were randomly assigned to the oxaliplatin-based Nordic FLOX regimen (control arm) or repeat sequential two FLOX cycles and two ICB cycles (experimental arm). The radiologic response was assessed every 8 weeks. In this post hoc analysis, we explored early target lesion (TL) dynamics as indicator of ICB responsiveness. Progression-free survival (PFS) was the primary endpoint.<h4>Results</h4>Using a landmark analysis approach, we categorised experimental-arm patients into ≥10% (N = 19) or <10% (N = 16) TL reduction at the first post-baseline response assessment. Median PFS for the groups was 16.0 (95% confidence interval (CI), 12.3-19.7) and 3.9 months (95% CI, 2.3-5.5), respectively, superior and inferior (both P < 0.01) to the median PFS of 9.8 months (95% CI, 4.9-14.7) for control arm patients (N = 31).<h4>Conclusions</h4>Radiologic TL reduction of ≥10% at the first post-baseline response assessment identified patients with ICB-responsive metastatic MSS/pMMR-CRC. This pragmatic measure may be used to monitor patients in investigational ICB schedules, enabling early treatment adaptation for unresponsive cases.<h4>Trial registration</h4>ClinicalTrials.gov number, NCT03388190 (02/01/2018).2022-01-01T00:00:00Z2022 Dec2026-05-28T00:39:08.034Z2025-04-04T23:36:43.876ZS-EPMC97268643622957910.1038/s41416-022-02004-0