A Multicenter Randomized Controlled Trial To Evaluate the Efficacy and Safety of Nelfinavir in Patients with Mild COVID-19.

Nelfinavir, an orally administered inhibitor of human immunodeficiency virus protease, inhibits the replication of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in vitro. We conducted a randomized controlled trial to evaluate the clinical efficacy and safety of nelfinavir in patients with SARS-CoV-2 infection. We included unvaccinated asymptomatic or mildly symptomatic adult patients who tested positive for SARS-CoV-2 infection within 3 days before enrollment. The patients were randomly assigned (1:1) to receive oral nelfinavir (750 mg; thrice daily for 14 days) combined with standard-of-care or standard-of-care alone. The primary endpoint was the time to viral clearance, confirmed using quantitative reverse-transcription PCR by assessors blinded to the assigned treatment. A total of 123 patients (63 in the nelfinavir group and 60 in the control group) were included. The median time to viral clearance was 8.0 (95% confidence interval [CI], 7.0 to 12.0) days in the nelfinavir group and 8.0 (95% CI, 7.0 to 10.0) days in the control group, with no significant difference between the treatment groups (hazard ratio, 0.815; 95% CI, 0.563 to 1.182; P = 0.1870). Adverse events were reported in 47 (74.6%) and 20 (33.3%) patients in the nelfinavir and control groups, respectively. The most common adverse event in the nelfinavir group was diarrhea (49.2%). Nelfinavir did not reduce the time to viral clearance in this setting. Our findings indicate that nelfinavir should not be recommended in asymptomatic or mildly symptomatic patients infected with SARS-CoV-2. The study is registered with the Japan Registry of Clinical Trials (jRCT2071200023). IMPORTANCE The anti-HIV drug nelfinavir suppresses the replication of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in vitro. However, its efficacy in patients with COVID-19 has not been studied. We conducted a multicenter, randomized controlled trial to evaluate the efficacy and safety of orally administered nelfinavir in patients with asymptomatic or mildly symptomatic COVID-19. Compared to standard-of-care alone, nelfinavir (750 mg, thrice daily) did not reduce the time to viral clearance, viral load, or the time to resolution of symptoms. More patients had adverse events in the nelfinavir group than in the control group (74.6% [47/63 patients] versus 33.3% [20/60 patients]). Our clinical study provides evidence that nelfinavir, despite its antiviral effects on SARS-CoV-2 in vitro, should not be recommended for the treatment of patients with COVID-19 having no or mild symptoms.

Serological response to a third dose of SARS-CoV-2 vaccine according to previous infection history

The IgG antibody titer against SARS-CoV-2 receptor binding protein (RBD) after mRNA vaccine were compared between those with and without previous infection (PI) for up to 48 weeks. Though sustained higher IgG-RBD were observed in the PI group after two doses of vaccines, both groups benefited from the booster shots of the third vaccine. This data supports the necessity of the booster shots to those with PI.

Serological response to a third dose of SARS-CoV-2 vaccine according to previous infection history.

The IgG antibody titer against SARS-CoV-2 receptor binding protein (RBD) after mRNA vaccine were compared between those with and without previous infection (PI) for up to 48 weeks. Though sustained higher IgG-RBD were observed in the PI group after two doses of vaccines, both groups benefited from the booster shots of the third vaccine. This data supports the necessity of the booster shots to those with PI.

Unique Evolution of SARS-CoV-2 in the Second Large Cruise Ship Cluster in Japan.

In the initial phase of the novel coronavirus disease (COVID-19) pandemic, a large-scale cluster on the cruise ship Diamond Princess (DP) emerged in Japan. Genetic analysis of the DP strains has provided important information for elucidating the possible transmission process of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on a cruise ship. However, genome-based analyses of SARS-CoV-2 detected in large-scale cruise ship clusters other than the DP cluster have rarely been reported. In the present study, whole-genome sequences of 94 SARS-CoV-2 strains detected in the second large cruise ship cluster, which emerged on the Costa Atlantica (CA) in Japan, were characterized to understand the evolution of the virus in a crowded and confined place. Phylogenetic and haplotype network analysis indicated that the CA strains were derived from a common ancestral strain introduced on the CA cruise ship and spread in a superspreading event-like manner, resulting in several mutations that might have affected viral characteristics, including the P681H substitution in the spike protein. Moreover, there were significant genetic distances between CA strains and other strains isolated in different environments, such as cities under lockdown. These results provide new insights into the unique evolution patterns of SARS-CoV-2 in the CA cruise ship cluster.

Performance of anti-SARS-CoV-2 antibody testing in asymptomatic or mild COVID-19 patients: A retrospective study in outbreak on a cruise ship.

OBJECTIVES: A few studies on antibody testing have focused on asymptomatic or mild coronavirus disease 2019 (COVID-19) patients with low initial anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody responses. Anti-SARS-CoV-2 antibody-testing performance was evaluated using blood samples from asymptomatic or mild COVID-19 patients. METHODS: Blood samples were collected from 143 COVID-19 patients during an outbreak on a cruise ship 3 weeks after diagnosis. Simultaneously, a follow-up SARS-CoV-2 genetic test was performed. Samples stored before the COVID-19 pandemic were also used to evaluate the lateral flow immunochromatographic assay (LFA) and electrochemiluminescence immunoassay (ECLIA). Titers of anti-SARS-CoV-2 IgM and IgG antibodies against the nucleocapsid and spike proteins were measured using the enzyme-linked immunosorbent assay to confirm which antibodies were influenced on LFA- and ECLIA- false-negative result in crew-member samples. RESULTS: Sensitivity, specificity, positive-predictive, and negative-predictive values of LFA-detected IgM antibodies were 0.231, 1.000, 1.000, and 0.613, respectively; those of LFA-detected IgG antibodies were 0.483, 0.989, 0.972, and 0.601, respectively; and those of ECLIA-detected total antibodies were 0.783, 1.000, 1.000, and 0.848, respectively. All antibody titers measured using ELISA were significantly lower in blood samples with negative results than in those with positive results in both LFA and ECLIA. In the patients with negative results from the follow-up genetic testing, IgM-, IgG-, and total-antibody positivity rates were 22.9%, 47.6%, and 72.4%, respectively. CONCLUSIONS: These findings suggest that anti-SARS-CoV-2 antibody testing has lower performance in asymptomatic or mild COVID-19 patients than required in the guidelines.

Epidemiology of Coronavirus Disease Outbreak among Crewmembers on Cruise Ship, Nagasaki City, Japan, April 2020.

In April 2020, a coronavirus disease (COVID-19) outbreak occurred on the cruise ship Costa Atlantica in Nagasaki, Japan. Our outbreak investigation included 623 multinational crewmembers onboard on April 20. Median age was 31 years; 84% were men. Each crewmember was isolated or quarantined in a single room inside the ship, and monitoring of health status was supported by a remote health monitoring system. Crewmembers with more severe illness were hospitalized. The investigation found that the outbreak started in late March and peaked in late April, resulting in 149 laboratory-confirmed and 107 probable cases of infection with severe acute respiratory syndrome coronavirus 2. Six case-patients were hospitalized for COVID-19 pneumonia, including 1 in severe condition and 2 who required oxygen administration, but no deaths occurred. Although the virus can spread rapidly on a cruise ship, we describe how prompt isolation and quarantine combined with a sensitive syndromic surveillance system can control a COVID-19 outbreak.

Detection of significant antiviral drug effects on COVID-19 with reasonable sample sizes in randomized controlled trials: A modeling study.

BACKGROUND: Development of an effective antiviral drug for Coronavirus Disease 2019 (COVID-19) is a global health priority. Although several candidate drugs have been identified through in vitro and in vivo models, consistent and compelling evidence from clinical studies is limited. The lack of evidence from clinical trials may stem in part from the imperfect design of the trials. We investigated how clinical trials for antivirals need to be designed, especially focusing on the sample size in randomized controlled trials. METHODS AND FINDINGS: A modeling study was conducted to help understand the reasons behind inconsistent clinical trial findings and to design better clinical trials. We first analyzed longitudinal viral load data for Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) without antiviral treatment by use of a within-host virus dynamics model. The fitted viral load was categorized into 3 different groups by a clustering approach. Comparison of the estimated parameters showed that the 3 distinct groups were characterized by different virus decay rates (p-value < 0.001). The mean decay rates were 1.17 d-1 (95% CI: 1.06 to 1.27 d-1), 0.777 d-1 (0.716 to 0.838 d-1), and 0.450 d-1 (0.378 to 0.522 d-1) for the 3 groups, respectively. Such heterogeneity in virus dynamics could be a confounding variable if it is associated with treatment allocation in compassionate use programs (i.e., observational studies). Subsequently, we mimicked randomized controlled trials of antivirals by simulation. An antiviral effect causing a 95% to 99% reduction in viral replication was added to the model. To be realistic, we assumed that randomization and treatment are initiated with some time lag after symptom onset. Using the duration of virus shedding as an outcome, the sample size to detect a statistically significant mean difference between the treatment and placebo groups (1:1 allocation) was 13,603 and 11,670 (when the antiviral effect was 95% and 99%, respectively) per group if all patients are enrolled regardless of timing of randomization. The sample size was reduced to 584 and 458 (when the antiviral effect was 95% and 99%, respectively) if only patients who are treated within 1 day of symptom onset are enrolled. We confirmed the sample size was similarly reduced when using cumulative viral load in log scale as an outcome. We used a conventional virus dynamics model, which may not fully reflect the detailed mechanisms of viral dynamics of SARS-CoV-2. The model needs to be calibrated in terms of both parameter settings and model structure, which would yield more reliable sample size calculation. CONCLUSIONS: In this study, we found that estimated association in observational studies can be biased due to large heterogeneity in viral dynamics among infected individuals, and statistically significant effect in randomized controlled trials may be difficult to be detected due to small sample size. The sample size can be dramatically reduced by recruiting patients immediately after developing symptoms. We believe this is the first study investigated the study design of clinical trials for antiviral treatment using the viral dynamics model.

Detection of SARS-CoV-2 using qRT-PCR in saliva obtained from asymptomatic or mild COVID-19 patients, comparative analysis with matched nasopharyngeal samples.

OBJECTIVES: The accurate detection of severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) is essential for the diagnosis of coronavirus disease 2019 (COVID-19). We compared the quantitative RT-PCR results between nasopharyngeal swabs and saliva specimens. METHODS: A COVID-19 outbreak occurred on a cruise ship at Nagasaki port, Japan. We obtained 123 nasopharyngeal swabs and saliva each from asymptomatic or mild patients in the late phase of infection. RESULTS: The intervals from the diagnosis to the sampling were 25.5 days for nasopharyngeal swabs and 28.9 days for saliva. The positive rate was 19.5% (24/123) for nasopharyngeal swabs and 38.2% (47/123) for saliva (P = 0.48). The quantified viral copies (mean ± SEM copies/5 µl) were 9.3±2.6 in nasopharyngeal swabs and 920±850 in saliva (P = 0.0006). CONCLUSIONS: The advantages of saliva specimens include positive rate improvement and accurate viral load detection. Saliva may be used as a reliable sample for SARS-CoV-2 detection.

Efficacy and safety of nelfinavir in asymptomatic and mild COVID-19 patients: a structured summary of a study protocol for a multicenter, randomized controlled trial.

OBJECTIVES: The aim of this trial is to evaluate the antiviral efficacy, clinical efficacy, and safety of nelfinavir in patients with asymptomatic and mild COVID-19. TRIAL DESIGN: The study is designed as a multicenter, open-label, blinded outcome assessment, parallel group, investigator-initiated, exploratory, randomized (1:1 ratio) controlled clinical trial. PARTICIPANTS: Asymptomatic and mild COVID-19 patients will be enrolled in 10 university and teaching hospitals in Japan. The inclusion and exclusion criteria are as follows: Inclusion criteria: (1) Japanese male or female patients aged ≥ 20 years (2) SARS-CoV-2 detected from a respiratory tract specimen (e.g., nasopharyngeal swab or saliva) using PCR, LAMP, or an antigen test within 3 days before obtaining the informed consent (3) Provide informed consent Exclusion criteria: (1) Symptoms developed ≥ 8 days prior to enrolment (2) SpO2 < 96 % (room air) (3) Any of the following screening criteria: a) ALT or AST ≥ 5 × upper limit of the reference range b) Child-Pugh class B or C c) Serum creatinine ≥ 2 × upper limit of the reference range and creatinine clearance < 30 mL/min (4) Poorly controlled diabetes (random blood glucose ≥ 200 mg/dL or HbA1c ≥ 7.0%, despite treatment) (5) Unsuitable serious complications based on the assessment of either the principal investigator or the sub-investigator (6) Hemophiliac or patients with a marked hemorrhagic tendency (7) Severe diarrhea (8) Hypersensitivity to the investigational drug (9) Breastfeeding or pregnancy (10) With childbearing potential and rejecting contraceptive methods during the study period from the initial administration of the investigational drug (11) Receiving rifampicin within the previous 2 weeks (12) Participated in other clinical trials and received drugs within the previous 12 weeks (13) Undergoing treatment for HIV infection (14) History of SARS-CoV-2 vaccination or wishes to be vaccinated against SARS-CoV-2 (15) Deemed inappropriate (for miscellaneous reasons) based on the assessment of either the principal investigator or the sub-investigator INTERVENTION AND COMPARATOR: Patients who meet the inclusion criteria and do not meet any of the exclusion criteria will be randomized to either the nelfinavir group or the symptomatic treatment group. The nelfinavir group will be administered 750 mg of nelfinavir orally, three times daily for 14 days (treatment period). However, if a participant tests negative on two consecutive PCR tests of saliva samples, administration of the investigational drug for that participant can be discontinued at the discretion of the investigators. The symptomatic treatment group will not be administered the investigational drug, but all other study procedures and conditions will be the same for both groups for the duration of the treatment period. After the treatment period of 14 days, each group will be followed up for 14 days (observational period). MAIN OUTCOMES: The primary endpoint is the time to negative conversion of SARS-CoV-2. During the study period from Day 1 to Day 28, two consecutive negative PCR results of saliva samples will be considered as the negative conversion of the virus. The secondary efficacy endpoints are as follows: For patients with both asymptomatic and mild disease: area under the curve of viral load, half decay period of viral load, body temperature at each time point, all-cause mortality, incidence rate of pneumonia, percentage of patients with newly developed pneumonia, rate of oxygen administration, and the percentage of patients who require oxygen administration. For asymptomatic patients: incidence of symptomatic COVID-19, incidence of fever (≥ 37.0 °C for two consecutive days), incidence of cough For patients with mild disease: incidence of defervescence (< 37.0 °C), incidence of recovery from clinical symptoms, incidence of improvement of each symptom The secondary safety endpoints are adverse events and clinical examinations. RANDOMIZATION: Patients will be randomized to either the nelfinavir group or the symptomatic treatment group using the electric data capture system (1:1 ratio, dynamic allocation based on severity [asymptomatic], and age [< 60 years]). BLINDING (MASKING): Only the assessors of the primary outcome will be blinded (blinded outcome assessment). NUMBERS TO BE RANDOMIZED (SAMPLE SIZE): The sample size was determined based on our power analysis to reject the null hypothesis, S (t | z =1) = S (t | z = 0) where S is a survival function, t is time to negative conversion, and z denotes randomization group, by the log-rank test with a two-sided p value of 0.05. We estimated viral dynamic parameters by fitting a nonlinear mixed-effects model to reported viral load data, and simulated our primary endpoint from viral-load time-courses that were realized from sets of viral dynamics parameters sampled from the estimated probability distribution of the parameters (sample size: 2000; 1000 each for randomization group). From this estimation of the hazard ratio between the randomization groups for the event of negative conversion using this simulation dataset, the required number of events for rejecting our null hypothesis with a power of 0.80 felled 97.345 by plugging the estimated hazard ratio, 1.79, in Freedman's equation. Therefore, we decided the required number of randomizations to be 120 after consideration of the frequency of censoring and the anticipated rate of withdrawal caused by factors such as withdrawal of consent. TRIAL STATUS: Protocol version 6.0 of February 12, 2021. Recruitment started on July 22, 2020 and is anticipated to be completed by March 31, 2022. TRIAL REGISTRATION: This trial was registered in Japan Registry of Clinical Trials (jRCT) ( jRCT2071200023 ) on 21 July 21, 2020. FULL PROTOCOL: The full protocol is attached as an additional file, accessible from the Trials website (Additional file 1). In the interest in expediting dissemination of this material, the familiar formatting has been eliminated; this Letter serves as a summary of the key elements of the full protocol. The study protocol has been reported in accordance with the Standard Protocol Items: Recommendations for Clinical Interventional Trials (SPIRIT) guidelines (Additional file 2).