How Much More Efficient Are Adaptive Platform Trials Than Multiple Stand-Alone Trials? A Comprehensive Simulation Study for Streamlining Drug Development During a Pandemic.

With the coronavirus disease 2019 (COVID-19) pandemic, there is growing interest in utilizing adaptive platform clinical trials (APTs), in which multiple drugs are compared with a single common control group, such as a placebo or standard-of-care group. APTs evaluate several drugs for one disease and accept additions or exclusions of drugs as the trials progress; however, little is known about the efficiency of APTs over multiple stand-alone trials. In this study, we simulated the total development period, total sample size, and statistical operating characteristics of APTs and multiple stand-alone trials in drug development settings for hospitalized patients with COVID-19. Simulation studies using selected scenarios reconfirmed several findings regarding the efficiency of APTs. The APTs without staggered addition of drugs showed a shorter total development period than stand-alone trials, but the difference rapidly diminished if patient's enrollment was accelerated during the trials owing to the spread of infection. APTs with staggered addition of drugs still have the possibility of reducing the total development period compared with multiple stand-alone trials in some cases. Our study demonstrated that APTs could improve efficiency relative to multiple stand-alone trials regarding the total development period and total sample size without undermining statistical validity; however, this improvement varies depending on the speed of patient enrollment, sample size, presence/absence of family-wise error rate adjustment, allocation ratio between drug and placebo groups, and interval of staggered addition of drugs. Given the complexity of planning and implementing APT, the decision to implement APT during a pandemic must be made carefully.

A Phase I/II Clinical Trial of Intradermal, Controllable Self-Replicating Ribonucleic Acid Vaccine EXG-5003 against SARS-CoV-2.

mRNA vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have played a key role in reducing morbidity and mortality from coronavirus disease 2019 (COVID-19). We conducted a double-blind, placebo-controlled phase I/II trial to evaluate the safety, tolerability, and immunogenicity of EXG-5003, a two-dose, controllable self-replicating RNA vaccine against SARS-CoV-2. EXG-5003 encodes the receptor binding domain (RBD) of SARS-CoV-2 and was administered intradermally without lipid nanoparticles (LNPs). The participants were followed for 12 months. Forty healthy participants were enrolled in Cohort 1 (5 µg per dose, n = 16; placebo, n = 4) and Cohort 2 (25 µg per dose, n = 16; placebo, n = 4). No safety concerns were observed with EXG-5003 administration. SARS-CoV-2 RBD antibody titers and neutralizing antibody titers were not elevated in either cohort. Elicitation of antigen-specific cellular immunity was observed in the EXG-5003 recipients in Cohort 2. At the 12-month follow-up, participants who had received an approved mRNA vaccine (BNT162b2 or mRNA-1273) >1 month after receiving the second dose of EXG-5003 showed higher cellular responses compared with equivalently vaccinated participants in the placebo group. The findings suggest a priming effect of EXG-5003 on the long-term cellular immunity of approved SARS-CoV-2 mRNA vaccines.

Influence of Brain Metastasis on Analgesia-Related Outcomes in Patients with Lung and Breast Cancers Treated with Naldemedine: A Propensity Score-Matched Analysis.

Naldemedine is structurally designed to prevent passage across the blood-brain barrier (BBB), resulting in the attenuation of opioid-induced constipation without interfering with the analgesic effects of opioids. However, the influence of brain metastasis (BM), as one indicator of BBB disruption, on the analgesic effects of opioids in patients treated with naldemedine remains unclear. To examine whether the analgesic effects of opioids following naldemedine treatment are lower in patients with BM than in those without BM, we surveyed inpatients with lung and breast cancers treated with naldemedine at Fujita Health University Hospital between April 2017 and March 2022. Changes in the numeric rating scale (NRS) scores, morphine milligram equivalents (MMEs), and the number of rescues were assessed as analgesia-related outcomes during the first 7 days of naldemedine treatment in patients with or without BM, matched by the propensity score. In total, 172 patients were enrolled. After propensity-score matching, 30 patients with BM and 60 patients without BM were included in the analysis. Changes in NRS scores, MMEs, and the number of rescues did not differ between patients with and without BM. In the linear mixed-effects model, the coefficient of interaction between patients with or without BM and the days for each outcome was not statistically significant. BM does not influence the analgesic effect of opioids in patients with lung and breast cancers treated with naldemedine. Naldemedine may be useful for treating BM.

Adjustment of creatinine clearance for carboplatin dosing in Calvert's formula and clinical efficacy for lung cancer.

BACKGROUND: The Cockcroft-Gault formula is commonly used as a substitute for glomerular filtration rate (GFR) in Calvert's formula for carboplatin dosing, where adjusting serum creatinine measured using the enzymatic method with 0.2 mg/dL has been suggested in Japan. However, the effects of these adjustments on efficacy in patients with non-small-cell lung cancer remain unknown. METHODS: We conducted a post hoc analysis of the PREDICT1 study (CJLSG1201), a multicenter prospective observational trial of carboplatin-pemetrexed. Glomerular filtration rate values in Calvert's formula were back-calculated from the administered dosages of carboplatin and the reported value of the target area under the curve. We estimated the serum creatinine adjustments and divided the patients into crude and adjusted groups. RESULTS: Patients in the crude group (N = 169) demonstrated similar efficacy to those in the adjusted group (N = 104) in progression-free survival (PFS) and overall survival (OS) (hazard ratio [HR], 1.02; 95% confidence interval [CI], 0.76-1.35; p = 0.916 vs. HR, 0.87; 95% CI, 0.65-1.17; p = 0.363), with higher grade 3-4 hematologic toxicity. Among patients aged ≥75 years, the crude group (N = 47) showed superior efficacy compared with the adjusted group (N = 17) in PFS and OS (HR, 0.37; 95% CI, 0.20-0.69; p = 0.002 vs. HR, 0.43; 95% CI, 0.23-0.82; p = 0.010). CONCLUSIONS: Serum creatinine adjustment may be associated with similar efficacy compared to the crude serum creatinine value. In older patients, the adjustment should be cautiously applied owing to the potential for reduced efficacy.

Favipiravir for symptomatic COVID-19: A nationwide observational cohort study.

INTRODUCTION: Favipiravir, an antiviral agent with activity against SARS-CoV-2, was made available to hospitals in Japan for off-label use among COVID-19 patients between 2020 and 2021. METHODS: A nationwide observational cohort study was conducted on patients who received favipiravir as part of clinical care between February 2020 and December 2021. Information was collected on demographics, comorbidities, severity of illness, use of favipiravir and other medications targeting COVID-19, adverse events, clinical status at 7 and 14 days and clinical outcome one month after admission to the hospital. RESULTS: A total of 17,508 hospitalized patients who received favipiravir were registered from 884 hospitals. In terms of demographics, 55.9% were age ≥60 years, and 62.3% were male. At least one of the four surveyed comorbidities was present in 45.5% of the patients. The rates of clinical improvement at 7 and 14 days were 72.4％ and 87.5%, 61.4% and 76.6%, and 45.4% and 59.5% for mild, moderate, and severe diseases, respectively. The case fatality rates within a month from hospitalization were 3.3%, 12.6%, and 29.1% for mild, moderate, and severe diseases, respectively. Significant correlations were observed between death and advanced age, male sex, moderate or severe disease, diabetes, cardiovascular diseases, and immunosuppression. Commonly reported adverse events included uric acid level increase or hyperuricemia (16.8%), liver function abnormalities (6.9%), and rash (1.0%). CONCLUSIONS: Favipiravir was well tolerated among COVID-19 patients. The study provides insights into the use of this agent at hospitals across Japan in the early phase of the pandemic.

Nab-Paclitaxel for Previously Treated Advanced Non-Small Cell Lung Cancer: Analysis of Safety and Efficacy for Patients With Renal Impairment.

BACKGROUND: Renal impairment can affect treatment tolerability and outcome in individuals with cancer. We aimed to assess the safety and efficacy of nab-paclitaxel for previously treated patients with advanced non-small cell lung cancer (NSCLC) and renal impairment enrolled in a phase 3 trial of nab-paclitaxel vs. docetaxel. PATIENTS AND METHODS: Previously treated NSCLC patients were randomly allocated (1:1) to receive docetaxel (60 mg/m²) on day 1 or nab-paclitaxel (100 mg/m²) on days 1, 8, and 15 of a 21-day cycle. Safety and efficacy outcomes of treatment were evaluated according to renal function. RESULTS: Among the 503 patients enrolled in the phase 3 trial, 17.3% had moderate renal impairment (creatinine clearance of ≤50 mL/min, n = 49 for docetaxel and n = 38 for nab-paclitaxel) and 53.1% had mild renal impairment (creatinine clearance of >50 to ≤80 mL/min, n = 133 for docetaxel and n = 134 for nab-paclitaxel). For patients with renal impairment, the incidence of febrile neutropenia was lower in the nab-paclitaxel group than in the docetaxel group. The difference in treatment efficacy for nab-paclitaxel vs. docetaxel among patients with moderate or mild renal impairment was similar to that among the overall study population. CONCLUSION: Nab-paclitaxel was found to be tolerable and beneficial for previously treated patients with advanced NSCLC and mild or moderate renal impairment.

Clinical characteristics and risk factors for mortality in patients with community-acquired staphylococcal pneumonia.

Staphylococcus aureus (S. aureus) is increasing in prevalence as a causative pathogen of community-acquired pneumonia (CAP). However, reports on the clinical features and mortality risk factors for S. aureus CAP are limited. We therefore aimed to identify the clinical characteristics and risk factors for mortality in these patients. We performed a post hoc and multivariate analysis of a multicenter prospective observational study that included adult hospitalized patients with S. aureus CAP. To elucidate the features of S. aureus CAP, we comparatively analyzed pneumococcal CAP (PCAP). We analyzed 196 patients with S. aureus CAP and 198 patients with PCAP. S. aureus CAP had a 30-day mortality of 16% (31/196) and a higher frequency of factors such as advanced age, comorbidities, poor functional ability, altered mental status, hypoalbuminemia, hyponatremia/hypernatremia, acidemia, and hypoxemia. In the multivariate analysis, the significant risk factors for mortality in S. aureus CAP were PaO2/FiO2 ≤250 [adjusted odds ratio (AOR), 3.29; 95% confidence interval (CI), 1.20-9.04] and albumin <3.0 g/dL (AOR, 2.41; 95% CI, 1.01-5.83). Non-ambulatory status tended to increase the risk (AOR, 2.40; 95% CI, 0.93-6.17). Methicillin resistance was not associated with mortality. In PCAP, hypoalbuminemia and non-ambulatory status affected mortality but hypoxemia did not. In conclusion, patients with S. aureus CAP have distinct clinical features, and their mortality risk factors can include hypoxemia and hypoalbuminemia. Physicians should recognize that the factors influencing mortality might differ somewhat among causative pathogens, and appropriate management should be performed after obtaining information on the causative pathogen.

Brigatinib in Japanese patients with tyrosine kinase inhibitor-naive ALK-positive non-small cell lung cancer: first results from the phase 2 J-ALTA study.

BACKGROUND: We evaluated the safety and efficacy of the anaplastic lymphoma kinase (ALK) tyrosine kinase inhibitor (TKI) brigatinib in Japanese patients with TKI-naive ALK-positive non-small cell lung cancer (NSCLC) from the phase 2, open-label, single-arm, multicenter J-ALTA study. METHODS: In the TKI-naive cohort of J-ALTA, the primary end point was independent review committee (IRC)-assessed 12-month progression-free survival (PFS). Secondary end points included objective response rate (ORR), intracranial response, overall survival (OS), and safety. RESULTS: The data were cut approximately 12 months after last patient enrollment. Thirty-two patients with ALK TKI-naive ALK-positive NSCLC were enrolled (median age [range], 60.5 [29-85] years; median duration of follow-up, 14.2 [3.2-19.3] months; median treatment duration, 13.8 [0.4-19.3] months). IRC-assessed 12-month PFS was 93.0% (90% confidence interval (CI) 79.2-97.8%); ORR, 96.9% (95% CI 83.8-99.9%), 12-month OS, 96.9% (95% CI 79.8-99.6%), and median OS was not reached. Of five patients with measurable baseline CNS metastases, two had partial intracranial response. The most common treatment-emergent adverse events were increased blood creatine phosphokinase (81%), hypertension (59%), and diarrhea (47%). Grade ≥ 3 adverse events occurred in 91% of patients; pneumonitis was reported in 3 (9%) patients. CONCLUSIONS: In the J-ALTA TKI-naive cohort, brigatinib demonstrated clinically meaningful efficacy consistent with the international phase 3 study. The safety profile in Japanese patients was consistent with previous studies. Brigatinib is an important first-line option for Japanese patients with ALK-positive NSCLC. CLINICAL REGISTRATION: NCT03410108.

Analyses of Ocular Adverse Reactions Associated With Anticancer Drugs Based on the Japanese Pharmacovigilance Database.

BACKGROUND/AIM: The systemic administration of anticancer drugs may cause ocular adverse reactions (OARs). However, such adverse events are generally rare and occur with an unknown frequency. This study aimed to investigate the tendency of occurrence of OARs induced by systemic anticancer drugs using a large spontaneous pharmacovigilance database in Japan. PATIENTS AND METHODS: The safety signals for eight OARs (periorbital and eyelid, conjunctival, corneal, scleral, lacrimal, lens, retinal, and optic nerve disorders) and their associations with anticancer drugs were evaluated by analyzing reporting odds ratios (RORs) and information components (ICs) based on data from the Japanese Adverse Drug Event Report (JADER). RESULTS: Safety signals associated with anticancer drugs were detected for periorbital and eyelid disorders (imatinib), conjunctival disorders (imatinib and lapatinib), corneal disorders (S-1, erlotinib, capecitabine, cetuximab, gefitinib, vandetanib, trastuzumab emtansine, lapatinib), lacrimal disorders (S-1, pembrolizumab), lens disorders (lenalidomide, pomalidomide, elotuzumab, tamoxifen, bexarotene, venetoclax), retinal disorders (encorafenib, binimetinib, tamoxifen, nab-paclitaxel, trametinib, dabrafenib), and optic nerve disorders (tamoxifen and blinatumomab). Some anticancer drugs showed differences in safety signals based on sex and age. CONCLUSION: Safety signals indicative of the risk of occurrence of OARs were observed for several anticancer drugs, and several hitherto unreported ocular adverse events requiring caution were also detected. Our results will help predict the occurrence of OARs by oncologists, ophthalmologists, pharmacists, and other healthcare professionals.

Lung cancer CT image generation from a free-form sketch using style-based pix2pix for data augmentation.

Artificial intelligence (AI) applications in medical imaging continue facing the difficulty in collecting and using large datasets. One method proposed for solving this problem is data augmentation using fictitious images generated by generative adversarial networks (GANs). However, applying a GAN as a data augmentation technique has not been explored, owing to the quality and diversity of the generated images. To promote such applications by generating diverse images, this study aims to generate free-form lesion images from tumor sketches using a pix2pix-based model, which is an image-to-image translation model derived from GAN. As pix2pix, which assumes one-to-one image generation, is unsuitable for data augmentation, we propose StylePix2pix, which is independently improved to allow one-to-many image generation. The proposed model introduces a mapping network and style blocks from StyleGAN. Image generation results based on 20 tumor sketches created by a physician demonstrated that the proposed method can reproduce tumors with complex shapes. Additionally, the one-to-many image generation of StylePix2pix suggests effectiveness in data-augmentation applications.

[Prognosis Prediction of Lung Cancer Patients Using CT Images: Feature Extraction by Convolutional Neural Network and Prediction by Machine Learning].

PURPOSE: Lung cancer accounts for the largest number of deaths among malignant tumors. Recently, more and more patients are concerned about their own life expectancy. CT examination is essential for the diagnosis of lung cancer. However, it is difficult to accurately predict the prognosis using CT images. In this study, we developed a method to predict the prognosis of lung cancer patients from CT images using a convolutional neural network (CNN) and a machine learning method. METHODS: In this study, the CT images of 173 lung cancer patients were collected. First, we selected the slice with the largest tumor size in each case and extracted features using a CNN. Next, we performed feature selection using information gain and predicted alive or death by classifiers. An artificial neural network or Naïve Bayes was used as a classifier and alive and death were predicted at one-year intervals from one year to five years later. RESULTS: We evaluated the prediction accuracy via the three-fold cross-validation method and found that the prediction accuracies were around 80% for all periods from 1 to 5 years. In the evaluation of the survival curve, the shape of the curve was close to the actual curve. CONCLUSION: These results indicate that feature extraction by a CNN and classification by the machine learning method may be effective in predicting the prognosis of lung cancer patients using CT images.

Newly developed artificial intelligence algorithm for COVID-19 pneumonia: utility of quantitative CT texture analysis for prediction of favipiravir treatment effect.

PURPOSE: Using CT findings from a prospective, randomized, open-label multicenter trial of favipiravir treatment of COVID-19 patients, the purpose of this study was to compare the utility of machine learning (ML)-based algorithm with that of CT-determined disease severity score and time from disease onset to CT (i.e., time until CT) in this setting. MATERIALS AND METHODS: From March to May 2020, 32 COVID-19 patients underwent initial chest CT before enrollment were evaluated in this study. Eighteen patients were randomized to start favipiravir on day 1 (early treatment group), and 14 patients on day 6 of study participation (late treatment group). In this study, percentages of ground-glass opacity (GGO), reticulation, consolidation, emphysema, honeycomb, and nodular lesion volumes were calculated as quantitative indexes by means of the software, while CT-determined disease severity was also visually scored. Next, univariate and stepwise regression analyses were performed to determine relationships between quantitative indexes and time until CT. Moreover, patient outcomes determined as viral clearance in the first 6 days and duration of fever were compared for those who started therapy within 4, 5, or 6 days as time until CT and those who started later by means of the Kaplan-Meier method followed by Wilcoxon's signed-rank test. RESULTS: % GGO and % consolidation showed significant correlations with time until CT (p < 0.05), and stepwise regression analyses identified both indexes as significant descriptors for time until CT (p < 0.05). When divided all patients between time until CT of 4 days and that of more than 4 days, accuracy of the combined quantitative method (87.5%) was significantly higher than that of the CT disease severity score (62.5%, p = 0.008). CONCLUSION: ML-based CT texture analysis is equally or more useful for predicting time until CT for favipiravir treatment on COVID-19 patients than CT disease severity score.

Nintedanib plus chemotherapy for nonsmall cell lung cancer with idiopathic pulmonary fibrosis: a randomised phase 3 trial.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is a fatal lung disease implicated as an independent risk factor for lung cancer. However, optimal treatment for advanced lung cancer with IPF remains to be established. We performed a randomised phase 3 trial (J-SONIC) to assess the efficacy and safety of nintedanib plus chemotherapy (experimental arm) compared with chemotherapy alone (standard-of-care arm) for advanced nonsmall cell lung cancer (NSCLC) with IPF. METHODS: Chemotherapy-naïve advanced NSCLC patients with IPF were allocated to receive carboplatin (area under the curve of 6 on day 1) plus nanoparticle albumin-bound paclitaxel (nab-paclitaxel) (100 mg·m-2 on days 1, 8 and 15) every 3 weeks with or without nintedanib (150 mg twice daily, daily). The primary end-point was exacerbation-free survival (EFS). RESULTS: Between May 2017 and February 2020, 243 patients were enrolled. Median EFS was 14.6 months in the nintedanib plus chemotherapy group and 11.8 months in the chemotherapy group (hazard ratio (HR) 0.89, 90% CI 0.67-1.17; p=0.24), whereas median progression-free survival was 6.2 and 5.5 months, respectively (HR 0.68, 95% CI 0.50-0.92). Overall survival was improved by nintedanib in patients with nonsquamous histology (HR 0.61, 95% CI 0.40-0.93) and in those at GAP (gender-age-physiology) stage I (HR 0.61, 95% CI 0.38-0.98). Seven (2.9%) out of 240 patients experienced acute exacerbation during study treatment. CONCLUSIONS: The primary end-point of the study was not met. However, carboplatin plus nab-paclitaxel was found to be effective and tolerable in advanced NSCLC patients with IPF. Moreover, nintedanib in combination with such chemotherapy improved overall survival in patients with nonsquamous histology.

Clinical characteristics of the first three waves of hospitalised patients with COVID-19 in Japan prior to the widespread use of vaccination: a nationwide observational study.

Background: Before widespread coronavirus disease (COVID-19) vaccinations, Japan experienced three COVID-19 epidemic waves. This study aimed to evaluate the characteristics of hospitalised COVID-19 patients and reveal temporal changes. Methods: This study included 33,554 hospitalised patients with COVID-19 from 553 healthcare facilities. Data were analysed by age group and epidemic wave (first wave, 01/01/2020-05/31/2020; second wave, 06/01/2020-10/31/2020; and third wave, 11/01/2020-03/31/2021). Findings: By age group, 3% (under 18), 22% (young), 34% (middle-aged), and 41% (older patients) were aged 0-17, 18-39, 40-64, and >65 years; while 16%, 35%, and 49% were in the first, second, and third wave, respectively. The patients' overall median age (58 years; interquartile range, 39-74) was lowest and highest during the second and third waves, respectively. The frequency of any comorbidity was lowest and highest during the second (44·5%) and third (63·6%) waves, respectively. The symptoms at admission and exposure history differed considerably with age. The overall case fatality rate (5%) was highest among older patients (11·4%). Case fatality rate was highest and lowest during the first (7·3%) and second (2·8%) waves, respectively. Medication use changed over time. Interpretation: Although the overall case fatality rate remained relatively low, it was more than twice as high among older patients. After adjusting for age and comorbidities, the risk of death was highest in the first wave. Funding: This work was supported by the Ministry of Health, Labour and Welfare "Research on Emerging and Re-emerging Infectious Diseases and Immunization" 19HA1003].

Effectiveness of Favipiravir on Nonsevere, Early-Stage COVID-19 in Japan: A Large Observational Study Using the COVID-19 Registry Japan.

INTRODUCTION: Several randomized controlled trials have compared the effectiveness of favipiravir with that of placebo. However, evidence regarding its effect on nonsevere, early-stage coronavirus disease 2019 (COVID-19) remains insufficient. METHODS: We used the COVID-19 Registry Japan, a nationwide registry of inpatients with COVID-19, for evaluating the effectiveness of favipiravir on patients with nonsevere, early-stage COVID-19. Eligible patients, who did not need supplementary oxygen therapy at admission, were classified according to two regimens (starting favipiravir therapy within 4 days from admission vs. no favipiravir during hospitalization) and were then compared using a three-step method (cloning, censoring, and weighting). The primary outcome was supplementary oxygen requirement during hospitalization, and the secondary outcomes were the need for invasive mechanical ventilation or extracorporeal membrane oxygenation (IMV/ECMO) and overall mortality at 30 days. RESULTS: A total of 7654 cases were analyzed. The "start favipiravir" regimen did not show substantial differences in the primary outcome [hazard ratio 0.825, 95% confidence interval (CI) 0.657-1.04, p = 0.098] and both of the secondary outcomes [need for IMV/ECMO and overall 30-day mortality, hazard ratio 1.02 (95% CI 0.649-1.60) and 0.869 (95% CI 0.519-1.46), p = 0.929 and 0.594, respectively]. CONCLUSIONS: In this large cohort from a COVID-19 registry, favipiravir was not associated with a positive effect on the clinical outcome on patients with nonsevere, early-stage COVID-19, suggesting that it is not an essential drug for COVID-19 treatment.

Effectiveness of remdesivir in hospitalized nonsevere patients with COVID-19 in Japan: A large observational study using the COVID-19 Registry Japan.

OBJECTIVES: To evaluate the effectiveness of remdesivir in the early stage of nonsevere COVID-19. Although several randomized controlled trials have compared the effectiveness of remdesivir with that of a placebo, there is limited evidence regarding its effect in the early stage of nonsevere COVID-19 cases. METHODS: We evaluated the effectiveness of remdesivir in the early stage of nonsevere COVID-19 using the COVID-19 Registry Japan, a nationwide registry of hospitalized patients with COVID-19 in Japan. Two regimens ("start remdesivir" therapy within 4 days from admission versus no remdesivir during hospitalization) among patients without the need for supplementary oxygen therapy were compared by a 3-step processing (cloning, censoring, and weighting) method. The primary outcome was a supplementary oxygen requirement during hospitalization. Secondary outcomes were 30-day in-hospital mortality and the risk of invasive mechanical ventilation or extracorporeal membrane oxygenation (IMV/ECMO). The data of 12,487 cases met our inclusion criteria. The "start remdesivir" regimen showed a lower risk of supplementary oxygen requirement (hazard ratio [HR]: 0.850, 95% confidence interval [CI]: 0.798-0.906, p value < 0.001). Both 30-day in-hospital mortality and risk of IMV/ECMO introduction were not significantly different between the 2 regimens (HRs: 1.04 and 0.983, 95% CI: 0.980-1.09 and 0.906-1.07, p values: 0.210 and 0.678, respectively). CONCLUSIONS: Remdesivir might reduce the risk of oxygen requirement during hospitalization in the early stage of COVID-19; however, it had no positive effect on the clinical outcome and reduction in IMV/ECMO requirement.

Antibody Responses to BNT162b2 Vaccination in Japan: Monitoring Vaccine Efficacy by Measuring IgG Antibodies against the Receptor-Binding Domain of SARS-CoV-2.

To fight severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes coronavirus disease 2019 (COVID-19), mass vaccination has begun in many countries. To investigate the usefulness of a serological assay to predict vaccine efficacy, we analyzed the levels of IgG, IgM, and IgA against the receptor-binding domain (RBD) of SARS-CoV-2 in the sera from BNT162b2 vaccinated individuals in Japan. This study included 219 individuals who received two doses of BNT162b2. The levels of IgG, IgM, and IgA against RBD were measured by enzyme-linked immunosorbent assay before and after the first and second vaccination, respectively. The relationship between antibody levels and several factors, including age, gender, and hypertension were analyzed. Virus-neutralizing activity in sera was measured to determine the correlation with the levels of antibodies. A chemiluminescent enzyme immunoassay (CLEIA) method to measure IgG against RBD was developed and validated for the clinical setting. The levels of all antibody isotypes were increased after vaccination. Among them, RBD-IgG was dramatically increased after the second vaccination. The IgG levels in females were significantly higher than in males. There was a negative correlation between age and IgG levels in males. The IgG levels significantly correlated with the neutralizing activity. The CLEIA assay measuring IgG against RBD showed a reliable performance and a high correlation with neutralizing activity. Monitoring of IgG against RBD is a powerful tool to predict the efficacy of SARS-CoV-2 vaccination and provides useful information in considering a personalized vaccination strategy for COVID-19. IMPORTANCE Mass vaccination campaigns using mRNA vaccines against SARS-CoV-2 have begun in many countries. Serological assays to detect antibody production may be a useful tool to monitor the efficacy of SARS-CoV-2 vaccination in individuals. Here, we reported the induction of antibody isotype responses after the first and second dose of the BNT162b2 vaccine in a well-defined cohort of employees in Japan. We also reported that age, gender, and hypertension are associated with differences in antibody response after vaccination. This study not only provides valuable information with respect to antibody responses after BNT162b2 vaccination in the Japanese population but also the usefulness of serological assays for monitoring vaccine efficacy in clinical laboratories to determine a personalized vaccination strategy for COVID-19.