Asymptomatic COVID-19 re-infection in a Japanese male by elevated half-maximal inhibitory concentration (IC50) of neutralizing antibodies.

INTRODUCTION: "Re-infection" with COVID-19 is a growing concern; re-infection cases have reported worldwide. However, the clinical characteristics of SARS-CoV-2 re-infection, including the levels and role of anti-SARS-CoV-2 Spike protein IgG antibodies and the half-maximal concentration (IC50) of neutralizing antibodies remain unknown. METHODS: Both the epidemiological and clinical information has been collected during two episodes of COVID-19 in a patient. Laboratory results, including RT-PCR, Ct values, anti-SARS-CoV-2 Spike protein IgG antibodies, and the IC50 of neutralizing antibodies levels were analyzed on the patient. RESULTS: The patient was a 58-year-old man who developed moderate COVID-19 pneumonia with oxygen demand (cannula 2 L/min) in the first episode. By day 30, he recuperated and was discharged after testing negative for SARS-CoV-2. After two and a half months, his three family members showed COVID-19 symptoms and tested positive for SARS-CoV-2. He tested positive for SARS-CoV-2 once again and was asymptomatic (the second episode). The IC50 of neutralizing antibodies against SARS-CoV-2 greatly increased from 50.0 µg/mL (after the first episode) to 14.8 µg/mL (after the second episode), and remained strongly reactive (20.1 µl/mL) after 47 days of the second episode. CONCLUSIONS: Epidemiological, clinical, and serological analyses confirmed that the patient had re-infection instead of persistent viral shedding from first infection. Our results suggest that SARS-CoV-2 re-infection may manifest as asymptomatic with increased neutralizing antibody levels. Further studies such as the virus characteristics, immunology, and epidemiology on SARS-CoV-2 re-infection are needed.

Real-world evidence of efficacy of pembrolizumab plus chemotherapy and nivolumab plus ipilimumab plus chemotherapy as initial treatment for advanced non-small cell lung cancer.

BACKGROUND: For advanced non-small cell lung cancer (NSCLC), combination therapies including a PD-1 inhibitor plus chemotherapy or a PD-1 inhibitor, CTLA-4 inhibitor, and chemotherapy are standard first-line options. However, data directly comparing these regimens are lacking. This study compared the efficacy of pembrolizumab plus chemotherapy (CP) against nivolumab plus ipilimumab and chemotherapy (CNI) in a real-world setting. METHODS: In this multicenter retrospective study, we compared the efficacy and safety of CP and CNI as first-line therapies in 182 patients with stage IIIB-IV NSCLC. Primary outcomes were overall survival (OS) and progression-free survival (PFS), while secondary outcomes included the response rate (RR) and safety profiles. Kaplan-Meier survival curves and Cox proportional hazards models were utilized for data analysis, adjusting for confounding factors such as age, gender, and PD-L1 expression. RESULTS: In this study, 160 patients received CP, while 22 received CNI. The CP group was associated with significantly better PFS than the CNI group (median 11.7 vs. 6.6 months, HR 0.56, p = 0.03). This PFS advantage persisted after propensity score matching to adjust for imbalances. No significant OS differences were observed. Grade 3-4 adverse events occurred comparably, but immune-related adverse events were numerically more frequent in the CNI group. CONCLUSIONS: In real-world practice, CP demonstrated superior PFS compared with CNI. These findings can inform treatment selection in advanced NSCLC.

Tailoring Therapeutic Strategies in Non-Small-Cell Lung Cancer: The Role of Genetic Mutations and Programmed Death Ligand-1 Expression in Survival Outcomes.

BACKGROUND: This study aims to assess the real-world impact of advancements in first-line systemic therapies for non-small-cell lung cancer (NSCLC), focusing on the role of driver gene mutations and programmed death-ligand 1 (PD-L1) expression levels. METHODS: Conducted across eight medical facilities in Japan, this multicenter, retrospective observational research included 863 patients diagnosed with NSCLC and treated between January 2015 and December 2022. The patients were categorized based on the type of systemic therapy received: cytotoxic agents, molecular targeting agents, immune checkpoint inhibitors, and combination therapies. Comprehensive molecular and immunohistochemical analyses were conducted, and statistical evaluations were performed. RESULTS: The median overall survival (OS) shows significant variations among treatment groups, with targeted therapies demonstrating the longest OS. This study also revealed that high PD-L1 expression was common in the group treated with immune checkpoint inhibitors. Multivariate analysis was used to identify the type of anticancer drug and the expression of PD-L1 at diagnosis as the impactful variables affecting 5-year OS. CONCLUSIONS: This study underscores the efficacy of targeted therapies and the critical role of comprehensive molecular diagnostics and PD-L1 expression in affecting OS in NSCLC patients, advocating for their integration into routine clinical practice.