Tocilizumab in COVID-19: a meta-analysis, trial sequential analysis, and meta-regression of randomized-controlled trials

PURPOSE: Interleukin-6 (IL-6) levels discriminate between patients with mild and severe COVID-19, making IL-6 inhibition an attractive therapeutic strategy. We conducted a systematic review, meta-analysis, trial sequential analysis (TSA), and meta-regression of randomized-controlled trials to ascertain the benefit of IL-6 blockade with tocilizumab for COVID-19. METHODS: We included randomized-controlled trials (RCTs) allocating patients with COVID-19 to tocilizumab. Our control group included standard care or placebo. Trials co-administering other pharmacological interventions for COVID-19 were not excluded. Primary outcome was 28–30 day mortality. Secondary outcomes included progression-to-severe disease defined as need for mechanical ventilation, intensive-care unit (ICU) admission, or a composite. RESULTS: We identified 10 RCTs using tocilizumab, 9 of which reported primary outcome data (mortality), recruiting 6493 patients with 3358 (52.2%) allocated to tocilizumab. Tocilizumab may be associated with an improvement in mortality (24.4% vs. 29.0%; OR 0.87 [0.74–1.01]; p = 0.07; I2 = 10%; TSA adjusted CI 0.66–1.14). Meta-regression suggested a relationship between treatment effect and mortality risk, with benefit at higher levels of risk (logOR vs %risk beta = −0.018 [−0.037 to −0.002]; p = 0.07). Tocilizumab did reduce the need for mechanical ventilation and was associated with a benefit in the composite secondary outcome but did not reduce ICU admission. CONCLUSIONS: For hospitalized COVID-19 patients, there is some evidence that tocilizumab use may be associated with a short-term mortality benefit, but further high-quality data are required. Its benefits may also lie in reducing the need for mechanical ventilation

Biological sex is associated with heterogeneous responses to IL-6 receptor inhibitor treatment in COVID-19—A retrospective cohort study

COVID-19 is associated with higher inflammatory markers, illness severity and mortality in males compared to females. Differences in immune responses to COVID-19 may underpin sex- specific outcome differences. We hypothesised that anti-IL-6 receptor monoclonal antibodies are associated with heterogenous treatment effects between male and female patients. We conducted a retrospective cohort study assessing the interaction between biological sex and anti-IL-6 receptor antibody treatment with respect to hospital mortality or progression of respiratory failure. We used a Cox proportional hazards regression model to adjust for age, ethnicity, steroid use, baseline C-reactive protein, and COVID-19 variant. We included 1274 patients, of which 58% were male and 15% received anti-IL-6 receptor antibodies. There was a significant interaction between sex and anti-IL-6 receptor antibody use on progression to respiratory failure or death (p = 0.05). For patients who did not receive anti-IL-6 receptor antibodies, the risk of death was slightly higher in males (HR = 1.13 (0.72–1.79)), whereas in patients who did receive anti-IL-6 receptor antibodies, the risk was lower in males (HR = 0.65 (0.32–1.33)). There was a heterogenous treatment effect with anti-IL-6 receptor antibodies between males and females; with anti-IL-6 receptor antibody use having a greater benefit in preventing progression to respiratory failure or death in males (p = 0.05)

Virological efficacy of PI monotherapy for HIV-1 in clinical practice.

BACKGROUND: Clinical trials of PI monotherapy indicate that most participants maintain viral suppression and emergent protease resistance is rare. However, outcomes among patients receiving PI monotherapy for clinical reasons, such as toxicity or adherence issues, are less well studied. METHODS: An observational study of patients attending an HIV treatment centre in London, UK, who had received PI monotherapy between 2004 and 2013, was conducted using prospectively collected clinical data and genotypic resistance reports. Survival analysis techniques were used to examine the times to virological failure and treatment discontinuation. RESULTS: Ninety-five patients had PI monotherapy treatment for a median duration of 126 weeks. Virological failure occurred during 64% of episodes and 8% of patients developed emergent protease mutations. We estimate failure occurs in half of episodes within 2 years following initiation. Where PI monotherapy was continued following virological failure, 68% of patients achieved viral re-suppression. Despite a high incidence of virological failure, many patients continued PI monotherapy and 79% of episodes were ongoing at the end of the study. The type of PI used, the presence of baseline protease mutations and the plasma HIV RNA at initiation did not have a significant impact on treatment outcomes. CONCLUSIONS: There was a higher incidence of virological failure and emerging resistance in our UK clinical setting than described in PI monotherapy clinical trials and other European observational studies. Despite this, many patients continued PI monotherapy and regained viral suppression, indicating this strategy remains a viable option in certain individuals following careful clinical evaluation

Convalescent plasma for COVID-19: a meta-analysis, trial sequential analysis, and meta-regression

Background: SARS-CoV-2-specific antibodies, particularly those preventing interaction between the viral spike receptor-binding domain and the host angiotensin-converting enzyme 2 receptor, may prevent viral entry into host cells and disease progression. / Objective: We performed a systematic review, meta-analysis, trials sequential analysis (TSA) and meta-regression of randomized control trials (RCTs) to evaluate the benefit of convalescent plasma for COVID-19. The primary outcome was 28-30-day mortality. Secondary outcomes included need for mechanical ventilation and intensive care (ICU) admission. / Data sources: PubMed, Embase, MedRxiv, and the Cochrane library on 2nd July 2021. / Results: Seventeen RCTs were identified recruiting 15,587 patients with 8027 (51.5%) allocated to receive convalescent plasma. Convalescent plasma use was not associated with a mortality benefit (24.7% vs. 25.5%; OR 0.94 (0.85 – 1.04); p = 0.23; I2 = 4%; TSA adjusted CI 0.84 – 1.05), or reduction in need for mechanical ventilation (15.7% vs. 15.4%; OR 1.01 [0.92 – 1.11]; p = 0.82; I2 = 0%; TSA adjusted CI 0.91 – 1.13), or ICU admission (22.4% vs. 16.7%; OR 0.80 (0.21 – 3.09); p = 0.75; I2 = 63%; TSA adjusted CI 0.0 – 196.05). Meta-regression did not reveal any association with titre of convalescent plasma, timing of administration, nor risk of death and treatment effect (p>0.05). Risk of bias was high in most studies. / Conclusions: In patients with COVID-19, there was no clear mortality benefit associated with convalescent plasma. In patients with mild disease, convalescent plasma did not prevent either the need for mechanical ventilation or ICU admission. PROSPERO registration CRD42021234201

Persistent Zika Virus Detection in Semen in a Traveler Returning to the United Kingdom from Brazil, 2016

Zika virus is normally transmitted by mosquitos, but cases of sexual transmission have been reported. We describe a patient with symptomatic Zika virus infection in whom the virus was detected in semen for 92 days. Our findings support recommendations for 6 months of barrier contraceptive use after symptomatic Zika virus infection

Instability of 8E5 calibration standard revealed by digital PCR risks inaccurate quantification of HIV DNA in clinical samples by qPCR

Establishing a cure for HIV is hindered by the persistence of latently infected cells which constitute the viral reservoir. Real-time qPCR, used for quantification of this reservoir by measuring HIV DNA, requires external calibration; a common choice of calibrator is the 8E5 cell line, which is assumed to be stable and to contain one HIV provirus per cell. In contrast, digital PCR requires no external calibration and potentially provides ‘absolute’ quantification. We compared the performance of qPCR and dPCR in quantifying HIV DNA in 18 patient samples. HIV DNA was detected in 18 by qPCR and in 15 by dPCR, the difference being due to the smaller sample volume analysed by dPCR. There was good quantitative correlation (R2 = 0.86) between the techniques but on average dPCR values were only 60% of qPCR values. Surprisingly, investigation revealed that this discrepancy was due to loss of HIV DNA from the 8E5 cell calibrant. 8E5 extracts from two other sources were also shown to have significantly less than one HIV DNA copy per cell and progressive loss of HIV from 8E5 cells during culture was demonstrated. We therefore suggest that the copy number of HIV in 8E5 extracts be established by dPCR prior to use as calibrator

Digital PCR dynamic range is approaching that of real-time quantitative PCR

Digital PCR (dPCR) has been reported to be more precise and sensitive than real-time quantitative PCR (qPCR) in a variety of models and applications. However, in the majority of commercially available dPCR platforms, the dynamic range is dependent on the number of partitions analysed and so is typically limited to four orders of magnitude; reduced compared with the typical seven orders achievable by qPCR. Using two different biological models (HIV DNA analysis and KRAS genotyping), we have demonstrated that the RainDrop Digital PCR System (RainDance Technologies) is capable of performing accurate and precise quantification over six orders of magnitude thereby approaching that achievable by qPCR

A Rapid Drug Resistance Genotyping Workflow for Mycobacterium tuberculosis, Using Targeted Isothermal Amplification and Nanopore Sequencing

Phenotypic drug susceptibility testing (DST) for tuberculosis (TB) requires weeks to yield results. Although molecular tests rapidly detect drug resistance-associated mutations (DRMs), they are not scalable to cover the full genome and the many DRMs that can predict resistance. Whole-genome sequencing (WGS) methods are scalable, but if conducted directly on sputum, typically require a target enrichment step, such as nucleic acid amplification. We developed a targeted isothermal amplification-nanopore sequencing workflow for rapid prediction of drug resistance of TB isolates. We used recombinase polymerase amplification (RPA) to perform targeted isothermal amplification (37°C for 90 min) of three regions within the Mycobacterium tuberculosis genome, followed by nanopore sequencing on the MinION. We tested 29 mycobacterial genomic DNA extracts from patients with drug-resistant (DR) TB and compared our results to those of WGS by Illumina and phenotypic DST to evaluate the accuracy of prediction of resistance to rifampin and isoniazid. Amplification by RPA showed fidelity equivalent to that of high-fidelity PCR (100% concordance). Nanopore sequencing generated DRM predictions identical to those of WGS, with considerably faster sequencing run times of minutes rather than days. The sensitivity and specificity of rifampin resistance prediction for our workflow were 96.3% (95% confidence interval [CI], 81.0 to 99.9%) and 100.0% (95% CI, 15.8 to 100.0%), respectively. For isoniazid resistance prediction, the sensitivity and specificity were 100.0% (95% CI, 86.3 to 100.0%) and 100.0% (95% CI, 39.8 to 100.0%), respectively. The workflow consumable costs per sample are less than £100. Our rapid and low-cost drug resistance genotyping workflow provides accurate prediction of rifampin and isoniazid resistance, making it appropriate for use in resource-limited settings

The CARMA study – children on early suppressive therapy: total HIV-1 DNA quantitation 12 years post ART initiation

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