Objective: This post-hoc analysis of the AtTEnd trial explored differences in the prognostic characteristics and in the efficacy of atezolizumab between Asians and non-Asians. Methods: The role of Asian race was evaluated on progression-free survival (PFS) using Cox-models and on time to appearance of new lesions using Fine and Gray models. Results: From October 2018 to February 2022, 549 patients were randomized, of whom, 20.4% were Asian. Asians showed a better prognostic profile in terms of age, body mass index, Eastern Cooperative Oncology Group performance status, disease status and previous treatments. The prognostic impact of Asian race on PFS was confirmed in the placebo arm (adjusted hazard ratio [HR]=0.41; 95% confidence interval [CI]=0.24–0.70). In proficient mismatch repair (pMMR) tumors, the HRs for PFS comparing atezolizumab versus placebo were 0.82 (95% CI=0.63–1.05) in non-Asians, and 1.42 (95% CI=0.80–2.50) in Asians. In the pMMR population randomized to atezolizumab, the subdistribution HRs comparing Asians to non-Asians were 0.68 (95% CI=0.43–1.09) for progression with new lesions and 1.21 (95% CI=0.73–2.03) for progression without new lesions. Asians showed a higher occurrence of severe adverse events in atezolizumab compared to placebo arm (Asians: 82.1% vs. 64.3%, p=0.036; non-Asian: 63.3% vs. 63.6%, p=0.949). Conclusion Race seems to affect the safety of the addition of atezolizumab and, in pMMR tumors, also its efficacy. In the atezolizumab arm, Asian patients seem to have a lower cumulative incidence of new lesions when primary tumor regrowth was considered a competing risk, and a higher cumulative incidence of primary tumor regrowth when new lesions appearance was the competing risk.

PURPOSE: The aim of this study was to present new a model that allows the study of the bone healing process, with an emphasis on the biological behavior of different graft-to-host interfaces. A standardized “over-inlay” surgical technique combined with a differential histomorphometric analysis is presented in order to optimize the use of critical-size calvarial defects in pre-clinical testing. METHODS: Critical-size defects were created into the parietal bone of 8 male Wistar rats. Deproteinized bovine bone (DBBM) blocks were inserted into the defects, so that part of the block was included within the calvarial thickness and part exceeded the calvarial height (an “over-inlay” graft). All animals were sacrificed at 1 or 3 months. Histomorphometric and immunohistochemical evaluation was carried out within distinct regions of interest (ROIs): the areas adjacent to the native bone (BA), the periosteal area (PA) and the central area (CA). RESULTS: The animals healed without complications. Differential morphometry allowed the examination of the tissue composition within distinct regions: the BA presented consistent amounts of new bone formation (NB), which increased over time (24.53%±1.26% at 1 month; 37.73%±0.39% at 3 months), thus suggesting that this area makes a substantial contribution toward NB. The PA was mainly composed of fibrous tissue (71.16%±8.06% and 78.30%±2.67%, respectively), while the CA showed high amounts of DBBM at both time points (78.30%±2.67% and 74.68%±1.07%, respectively), demonstrating a slow remodeling process. Blood vessels revealed a progressive migration from the interface with native bone toward the central area of the graft. Osterix-positive cells observed at 1 month within the PA suggested that the periosteum was a source of osteoprogenitor elements. Alkaline phosphatase data on matrix deposition confirmed this observation. CONCLUSIONS: The present model allowed for a standardized investigation of distinct graft-to-host interfaces both at vertically augmented and inlay-augmented sites, thus possibly limiting the number of animals required for pre-clinical investigations.
Alkaline Phosphatase ; Animals ; Blood Vessels ; Bone Regeneration* ; Bone Transplantation ; Humans ; Male ; Osteogenesis ; Parietal Bone ; Periosteum ; Rats* ; Rats, Wistar ; Skull ; Transplants*