Efficacy of combined COVID-19 convalescent plasma with oral RNA-dependent RNA polymerase inhibitor treatment versus neutralizing monoclonal antibody therapy in COVID-19 outpatients: a multi-center, non-inferiority, open-label randomized controlled trial (PlasMab)

Lessons from the Use of Monoclonal Antibodies to SARS-CoV-2 Spike Protein During the COVID-19 Pandemic

Monoclonal antibodies (mAbs) targeting the SARS-CoV-2 Spike protein were deployed during the COVID-19 pandemic. While all of the clinically authorized mAbs were eventually defeated by SARS-CoV-2 variants, they were highly effective in preventing disease progression when given early in the course of the disease. The experience with mAbs to SARS-CoV-2 offers important lessons for the use of mAbs in future infectious disease emergencies, such as choosing mAbs that target conserved epitopes and designing cocktails to reduce the emergence of escape variants. Planning for future use must include the creation of infusion centers and the development of strategies to minimize the emergence of escape variants.

Assessing favipiravir impact on SARS-CoV-2 transmission within households: Insights from a multi-center study (FaviPrev)

Background

While certain studies have demonstrated that antiviral treatment administered to index patients with influenza can mitigate the transmission within households, the efficacy of anti-SARS-CoV-2 agents in curtailing household transmission remains to be conclusively established.

Methods

A retrospective study conducted from April 2021 to May 2022 across multiple centers in Thailand compared 892 individuals treated with favipiravir to 84 who received standard treatment among mild to moderate COVID-19 index patients. The study focused on the impact of favipiravir treatment in reducing household SARS-CoV-2 transmission by examining the secondary attack rate.

Results

Favipiravir significantly reduced household SARS-CoV-2 transmission, comparing 1836 household contacts with favipiravir-treated index cases to 170 contacts whose index cases received standard care. Favipiravir led to a 58 % secondary attack rate, substantially lower than the 71.8 % observed with standard treatment, representing a 54 % reduction in transmission likelihood, with an odds ratio of 0.46 (95 % confidence interval [CI] [0.23-0.89]). Index cases treated with favipiravir also demonstrated a relative risk reduction of 0.19 in transmission (95 % CI [0.11-0.27]). Remarkably, favipiravir effectiveness was most notable in unvaccinated index cases, those with symptomatic infections, individuals living in shared spaces like dormitories, flats, or apartments, and those not adhering to mask-wearing within their households.

Conclusions

Favipiravir has demonstrated in this study an indirect role in reducing household SARS-CoV-2 transmission, showing notable efficacy in symptomatic and unvaccinated index cases. This breakthrough highlights its potential in broader public health strategies. Exploring the roles and challenges of other anti-SARS-CoV-2 agents remains a vital goal in ongoing research.

Unveiling therapeutic dynamics: An in-depth comparative analysis of neutralizing monoclonal antibodies and favipiravir in alleviating COVID-19 outpatients impacts among middle-aged and special populations (MA-FAST)

BACKGROUND

Neutralizing monoclonal antibodies (NMabs) are recognized for their efficacy against non-severe COVID-19. However, spike protein mutations may confer resistance. This study evaluates the effectiveness of favipiravir (FPV) versus NMabs in preventing severe COVID-19 in special populations.

METHODS

A retrospective cohort was conducted on middle-aged, elderly, diabetic, or obese patients with COVID-19 treated with either FPV or NMabs. Propensity score matching (PSM) was used for analysis.

RESULTS

The study included 1410 patients, resulting in four cohorts: middle-aged (36), elderly (48), diabetic (46), and obese (28) post-PSM. No significant differences were noted in 28-day emergency department (ED) visits across all groups between NMabs and FPV treatments, despite lower immunity in the FPV group. However, the diabetic group treated with FPV had higher 28-day hospitalization and oxygen supplemental, with no differences in the other groups. Intensive care unit (ICU) admissions, invasive mechanical ventilation, and mortality rates were similar between the two treatments.

CONCLUSIONS

Early dose-adjusted FPV showed no difference from NMabs in preventing ED visits, ICU admissions, ventilator needs, or mortality among patients with major comorbidities. Diabetic patients on FPV experienced higher hospitalizations and oxygen needs, with no observed differences in other groups. FPV may be a viable alternative, especially in settings with limited resources.

Exploring Study Design Foibles in Randomized Controlled Trials on Convalescent Plasma in Hospitalized COVID-19 Patients

Background: Sample size estimation is an essential step in the design of randomized controlled trials (RCTs) evaluating a treatment effect. Sample size is a critical variable in determining statistical significance and, thus, it significantly influences RCTs' success or failure. During the COVID-19 pandemic, many RCTs tested the efficacy of COVID-19 convalescent plasma (CCP) in hospitalized patients but reported different efficacies, which could be attributed to, in addition to timing and dose, inadequate sample size estimates. Methods: To assess the sample size estimation in RCTs evaluating the effect of treatment with CCP in hospitalized COVID-19 patients, we searched the medical literature between January 2020 and March 2024 through PubMed and other electronic databases, extracting information on expected size effect, statistical power, significance level, and measured efficacy. Results: A total of 32 RCTs were identified. While power and significance level were highly consistent, heterogeneity in the expected size effect was relevant. Approximately one third of the RCTs did not reach the planned sample size for various reasons, with the most important one being slow patient recruitment during the pandemic's peaks. RCTs with a primary outcome in favor of CCP treatment had a significant lower median absolute difference in the expected size effect than unfavorable RCTs (20.0% versus 33.9%, P = 0.04). Conclusions: The analyses of sample sizes in RCTs of CCP treatment in hospitalized COVID-19 patients reveal that many underestimated the number of participants needed because of excessively high expectations on efficacy, and thus, these studies had low statistical power. This, in combination with a lower-than-planned recruitment of cases and controls, could have further negatively influenced the primary outcomes of the RCTs.

SARS-CoV-2 infection, vaccination and in vitro fertilization treatment: A prospective cohort study

BACKGROUND

The impact of COVID-19 on reproductive health is controversial. The association between female SARS-CoV-2 infection and laboratory and pregnancy outcomes following subsequent in vitro fertilization (IVF) treatment remains unclear. This study aimed to investigate the relationship between IVF treatment at different time intervals after SARS-CoV-2 infection and reproductive outcomes.

METHODS

A prospective cohort study of 920 IVF cycles post-SARS-CoV-2 infection was conducted. Modified Poisson regression and logistic regression models were utilized to evaluate oocyte- and embryo-related outcomes as well as clinical outcomes. Stratified analyses were also performed based on the vaccination status of the female participants.

RESULTS

SARS-CoV-2 infection within three months was associated with reduced available [Adjusted RR (aRR): 0.96, 95 %CI: 0.91-1.00] and top-quality embryos (aRR: 0.90, 95 %CI: 0.83-0.98) in subsequent IVF treatment. Among patients failing to finish the three-dose vaccination, the interval between SARS-CoV-2 infection and cycle initiation of less than 90 days was associated with a lower number of oocytes retrieval (aRR: 8.81, 95 %CI: 8.24-9.41 vs aRR: 9.64, 95 %CI: 9.06-10.25), available embryos (aRR: 0.93, 95 %CI: 0.88-0.99), and top-quality embryos (aRR: 0.81, 95 %CI: 0.72-0.91) rather than among fully vaccinated women. Moreover, COVID-19 infection was not associated with biochemical pregnancy, clinical pregnancy, embryo implantation, and early abortion either in fresh embryo transfer (ET) or frozen ET.

CONCLUSIONS

This study indicated that initiating IVF treatment within 90 days of SARS-CoV-2 infection might reduce the likelihood of obtaining available and top-quality embryos, especially among those who had not completed the three-dose vaccination. Nevertheless, female COVID-19 infection did not affect pregnancy or early abortion. Further rigorously designed studies are required to support these findings.

Sotrovimab: A Review of Its Efficacy against SARS-CoV-2 Variants

Among the anti-Spike monoclonal antibodies (mAbs), the S-309 derivative sotrovimab was the most successful in having the longest temporal window of clinical use, showing a high degree of resiliency to SARS-CoV-2 evolution interrupted only by the appearance of the BA.2.86* variant of interest (VOI). This success undoubtedly reflects rational selection to target a highly conserved epitope in coronavirus Spike proteins. We review here the efficacy of sotrovimab against different SARS-CoV-2 variants in outpatients and inpatients, discussing both randomized controlled trials and real-world evidence. Although it could not be anticipated at the time of its development and introduction, sotrovimab's use in immunocompromised individuals who harbor large populations of variant viruses created the conditions for its eventual demise, as antibody selection and viral evolution led to its eventual withdrawal due to inefficacy against later variant lineages. Despite this, based on observational and real-world data, some authorities have continued to promote the use of sotrovimab, but the lack of binding to newer variants strongly argues for the futility of continued use. The story of sotrovimab highlights the power of modern biomedical science to generate novel therapeutics while also providing a cautionary tale for the need to devise strategies to minimize the emergence of resistance to antibody-based therapeutics.