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Six-months immunogenicity of COVID-19 mRNA-BNT162b2 vaccine in actively treated cancer patients: Updated results of the Vax-On study, Annals of Oncology (2022), doi:

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Background: Anti-SARS-CoV-2 mRNA vaccines can deeply affect cell-mediated immune responses in immunocompromised recipients, including cancer patients receiving active treatments. The clinical implications of changes in peripheral blood lymphocyte subsets following the third dose of mRNA-BNT162b2 vaccination (tozinameran) in patients on immune checkpoint blockade are not fully understood. We conducted a prospective analysis of the Vax-On-Third-Profile study to evaluate the impact of circulating lymphocyte dynamics on disease outcomes in this subgroup of patients. Methods: Recipients of booster dosing who had received before vaccination at least one course of an anti-PD-1/PD-L1 treatment for an advanced solid tumor were eligible. Immunophenotyping of peripheral blood was performed before the third dose of tozinameran (timepoint-1) and four weeks later (timepoint-2) to quantify the absolute counts of lymphocyte subpopulations, including CD3+CD4+ T cells, CD3+CD8+ T cells, B cells, and NK cells. Logistic regression was used to analyze the relationship between lymphocyte subsets and durable clinical benefit (DCB). The log-rank test and Cox regression model were applied to evaluate the relationship between lymphocyte subpopulations and both vaccine-related time-to-treatment failure (V-TTF) and overall survival (OS). Results: We included a total of 56 patients with metastatic disease who were given a third dose of tozinameran between 23 September and 7 October 2021 (median age: 66 years; male: 71%). Most recipients had a diagnosis of lung cancer and were being treated with pembrolizumab or nivolumab. Compared to baseline, the third immunization resulted in an incremental change in the median counts of all lymphocyte subpopulations, which was statistically significant only for NK cells (p < 0.001). A significant correlation was found between NK cell counts and DCB at timepoint-2 (p < 0.001). Multivariate logistic regression analysis of DCB confirmed the predictive significance of high-level NK cell counts (p = 0.020). In multivariate Cox regression analysis, high-level NK cell counts independently predicted longer V-TTF [HR 0.34 (95% CI 0.14–0.80), p = 0.014] and OS [HR 0.36 (95% CI 0.15–0.89, p = 0.027]. Conclusions: Our data suggest expansion of NK cell counts as the most noteworthy change in circulating lymphocytes after the third dose of tozinameran in cancer patients receiving PD-1/PD-L1-targeted agents. This change correlated with enhanced therapeutic efficacy, improving the rate of disease control, and prolonging survival outcomes. Similar findings have not been previously reported, implying that they have proof-of-concept value and warrant further confirmation.

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The aim of this study was to evaluate the association of circulating lymphocytes profiling with antibody response in cancer patients receiving the third dose of COVID-19 mRNA-BNT162b2 vaccine. Immunophenotyping of peripheral blood was used to determine absolute counts of lymphocyte subsets, alongside detection of IgG antibodies against receptor-binding-domain (RBD) of the SARS-CoV-2 Spike protein (S1) before booster dosing (timepoint-1) and four weeks afterward (timepoint-2). An IgG titer ≥ 50 AU/mL defined a positive seroconversion response. An IgG titer ≥ 4446 AU/mL was assumed as a correlate of 50% vaccine efficacy against symptomatic infections. A total of 258 patients on active treatment within the previous six months were enrolled between September 23 and October 7, 2021. The third dose resulted in an exponential increase in median anti-RBD-S1 IgG titer (P < 0.001), seroconversion rates (P < 0.001), and 50% vaccine efficacy rates (P < 0.001). According to ROC curve analysis, T helper and B cells were significantly associated with seroconversion responses at timepoint-1, whereas only B cells were relevant to 50% vaccine efficacy rates at timepoint-2. A positive linear correlation was shown between anti-RBD-S1 IgG titers and these lymphocyte subset counts. Multivariate analysis ruled out a potential role of T helper cells but confirmed a significant interaction between higher B cell levels and improved antibody response. These findings suggest that peripheral counts of B cells correlate with humoral response to the third dose of mRNA-BNT162b2 vaccine in actively treated cancer patients and could provide insights into a more comprehensive assessment of vaccination efficacy.

Background: To date, a consensus has not yet been reached about the therapy sequence after disease progression (PD) on CDK4/6 inhibitors in patients with HR+/HER2- metastatic breast cancer (MBC). Objectives: The present study assesses, in a real-world setting, the activity of different subsequent therapies in patients who experienced a PD on palbociclib (P) + endocrine therapy (ET), to evaluate the best therapy sequence. Methods: This is a multicenter retrospective observational study. Records of consecutive HR+/HER2- MBC patients from January 2017 to May 2019 were reviewed. The primary endpoint was the evaluation of progression-free survival (PFS) according to subsequent treatment lines after progression on P+ET. Toxicity data were also collected. Results: The outcomes were analyzed in 89 MBC patients that had progressed on previous P+ET: 17 patients were on hormone therapy (HT) and 31 patients on chemotherapy (CT) as second-line treatments; seven patients were on HT and 34 on CT as third-line therapies. PFS of patients treated with HT as second-line therapy is significantly improved when compared with patients treated with CT (p=0.01). Considering third-line settings, the difference in PFS was not statistically different between HT and CT. A better outcome in terms of toxicity is observed among HT patients for both second- and third-line therapies. Conclusions: patients who were progressive on P+ET could still benefit from a subsequent ET. In patients who experienced a good efficacy from prior ET, without visceral metastatic sites, HT seems the most suitable option, when compared to CT, also in terms of safety.

The recent addition of cyclin-dependent kinase 4 (CDK4) and CDK6 inhibitors to endocrine therapy has remarkably improved the outcome of patients affected with hormone receptor positive (HR+), human epidermal grow factor receptor 2 negative (HER2 -) advanced breast cancer (ABC). Ribociclib showed to be effective across most subgroups, regardless of the number and the site of metastasis. Up to 10% of patients with ABC, reported an oligometastatic condition, recently defined as a slow-volume metastatic disease with limited number and size of metastatic lesions (up to 5 and not necessarily in the same organ), potentially amenable for local treatment, aimed at achieving a complete remission status. Despite the wide use of CDK4/6 inhibitors in HR+, HER2-, ABC treatment, data regarding both locally advanced, inoperable disease and oligometastatic conditions are still poor. We reported a review and case series of HR+, HER2-, ABC patients treated with ribociclib as first-line therapy, for a locally advanced and oligometastatic conditions, reporting an impressive response and good safety profile.