Antiviral combination therapies for persistent COVID-19 in immunocompromised patients

Early combination of sotrovimab with nirmatrelvir/ritonavir or remdesivir is associated with low rate of persisting SARS CoV-2 infection in immunocompromised outpatients with mild-to-moderate COVID-19: a prospective single-centre study

BACKGROUND

Immunocompromised patients are at high risk of developing persisting/prolonged COVID-19. Data on the early combined use of antivirals and monoclonal antibodies in this population are scarce.

RESEARCH DESIGN AND METHODS

We performed an observational, prospective study, enrolling immunocompromised outpatients with mild-to-moderate COVID-19, treated with a combination of sotrovimab plus one antiviral (remdesivir or nirmatrelvir/ritonavir) within 7 days from symptom onset. Primary outcome was hospitalization within 30 days. Secondary outcomes were: needing for oxygen therapy; development of persistent infection; death within 60 days and reinfection or relapse within 90 days.

RESULTS

We enrolled 52 patients. No patient was hospitalized within 30 days of disease onset, required oxygen administration, died within 60 days, or experienced a reinfection or clinical relapse within 90 days.The clearance rates were 67% and 97% on the 14th day after the end of therapy and at the end of the follow-up period, respectively.Factors associated with longer infection were initiation of therapy 3 days after symptom onset and enrollment for more than 180 days from the beginning of the study. However, only the latter factor was independently associated with a longer SARS-CoV-2 infection, suggesting a loss of efficacy of this strategy with the evolution of SARS-CoV-2 variants.

CONCLUSIONS

Early administration of combination therapy with a direct antiviral and sotrovimab seems to be effective in preventing hospitalization, progression to severe COVID-19, and development of prolonged/persisting SARS-CoV-2 infection in immunocompromised patients.

Case Report: Persistent COVID-19 in a fully vaccinated Japanese man being treated with rituximab and epcoritamab for diffuse large B-cell lymphoma

The management of persistent coronavirus disease 2019 (COVID-19) in patients with hematological malignancies who are immunocompromised because of underlying disease or iatrogenic immunosuppression remains clinically challenging. Herein, we report an 84-year-old man with stage 3 diffuse large B-cell lymphoma treated with rituximab and epcoritamab who subsequently developed persistent severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, despite having received seven doses of COVID-19 mRNA vaccine and remdesivir. The patient was treated with a combination of remdesivir, sotrovimab, and nirmatrelvir/ritonavir, and recovered clinically. SARS-CoV-2 polymerase chain reaction and antigen tests eventually turned negative, and he was discharged after 28 days of hospitalization. This case highlights the challenges associated with managing persistent SARS-CoV-2 infection in immunocompromised patients with hematological malignancies. Combined treatment with antivirals and monoclonal antibodies may be an effective strategy.

Early combined therapy for COVID-19 in immunocompromised patients: a promising approach against viral persistence and drug resistance

Immunocompromised (IC) patients face significant challenges in managing COVID-19 due to their heightened susceptibility to severe illness, persistent infections, and the potential development of drug resistance. Studies indicate that IC patients, particularly those with hematologic malignancies (HM), hematopoietic stem cell transplants (HSCTR), or solid organ transplants (SOTR), experience higher mortality rates and worse outcomes compared to the general population, even post-vaccination. The persistence of the virus in these patients, combined with its rapid mutation, further complicates treatment. Recent evidence supports the use of combined neutralizing monoclonal antibodies (mAbs) and direct-acting antivirals (DAAs) as a more effective approach to viral clearance, reducing mortality, and preventing relapses. However, the rise of resistant variants, especially to mAbs, and concerns about the safety of prolonged or intensive therapies pose ongoing challenges. Monotherapies often fail short to address these issues, highlighting the need for early combined therapy (ECT) with mAbs and DAAs. ECT has shown promise in managing COVID-19 in IC individuals by targeting multiple stages of the viral lifecycle, reducing viral load, and clearing infections at earlier stages, which helps mitigate the risks of severe disease and drug resistance. Continued research is essential to refine these treatment protocols, especially as the virus evolves. Although further studies are needed, current findings suggest that ECT may become the standard of care for managing COVID-19 in severely IC patients, offering better clinical outcomes and hindering viral persistence.

The conserved core nuclear egress complex (NEC) as an antiherpesviral drug target: Pharmacophore-based identification of NEC-specific inhibitors

The nucleocytoplasmic capsid egress of herpesviruses is a uniquely regulated process. As well-established for the human cytomegalovirus (HCMV) core nuclear egress complex (NEC), the pUL50-pUL53 NEC heterodimer oligomerizes and builds hexameric lattices for the regulated nucleocytoplasmic release of viral capsids. Recently, we and others validated the NEC as a novel target for antiviral strategies. So far, the experimental targeting approaches included the development of NEC-directed small molecules, cell-penetrating peptides, NEC-specific mutagenesis, and the expression of NEC-interfering protein constructs. Our current postulate states that a small molecule-mediated interference with the assembly of the core NEC prevents NEC-dependent egress regulation and thereby strictly limits viral replication. Here, we present an experimental proof of this antiviral strategy, and the data provide evidence for the following points: (i) pharmacophore-based approaches demonstrated to be successful in the identification of NEC-specific inhibitory small molecules, (ii) already a low number of 36 analyzed small molecules yielded eight experimental hits with micromolar to submicromolar antiviral activity, (iii) their antiviral potency was asserted to the predicted NEC-interfering mode-of-action, (iv) two identified hit compounds presented a broad antiherpesviral activity, and (v) a further pharmacophore-assisted refinement of NEC-directed molecules may lead to the development of highly effective and even broadly acting antivirals. Combined, we strengthen the recently postulated potential of the NEC as a next-generation antiherpesviral drug target by identifying broadly active NEC inhibitors via a pharmacophore-based approach.

Amphibian-Derived Peptides as Natural Inhibitors of SARS-CoV-2 Main Protease (Mpro): A Combined In Vitro and In Silico Approach

The COVID-19 pandemic, caused by the SARS-CoV-2 virus, has highlighted the urgent need for novel therapeutic agents targeting viral enzymes such as the main protease (Mpro), which plays a crucial role in viral replication. In this study, we investigate the inhibitory potential of 23 peptides isolated from the skin of amphibians belonging to the Hylidae and Leptodactylidae families against SARS-CoV-2 Mpro. Five peptides demonstrated significant inhibition using a colorimetric Mpro inhibition assay, with IC50 values ranging from 41 to 203 µM. Among these, peptides Hp-1081 and Hp-1971, derived from Boana pulchella, exhibited the strongest activity, comparable to the natural Mpro inhibitor quercetin. The binding mechanism of the most potent peptide, Hp-1081, was further investigated through docking and molecular dynamics (MDs) simulations and energetic analysis, which revealed key Mpro residues involved in the binding process. Moreover, because SARS-CoV-2 infection can induce ROS overproduction, the antioxidant activity of Hp-1081 was assessed, reaching 48% of DPPH radical scavenging activity at 100 µM. The most potent peptides also showed no toxicity against human erythrocytes and Artemia salina. This study provides insight into the antiviral potential of amphibian-derived peptides and highlights their applicability as natural templates for drug development targeting coronaviruses.

Antiviral combination treatment strategies for SARS-CoV-2 infection in immunocompromised patients

PURPOSE OF REVIEW

The purpose of this review is to report the available evidence regarding the use of combination regimens of antivirals and/or antibody-based therapy in the treatment of SARS-CoV-2 in immunocompromised patients.

RECENT FINDINGS

Literature search identified 24 articles, excluding single case reports, which included mainly patients with hematological malignancies and/or B-cell depletion. Data were divided based on the timing and reason for administration of combination treatment, that is, early treatment to prevent progression to severe COVID-19 and treatment of prolonged or relapsed infection. We described the treated populations, treatment duration and composition of combination treatment. We briefly addressed new treatment options and we proposed an algorithm for the management of COVID-19 infection in patients affected by hematological malignancies.

SUMMARY

Combination treatment seems an effective (73-100%) and well tolerated (<5% reported bradycardia, hepatotoxicity, neutropenia) strategy for treating prolonged/relapsed SARS-CoV-2 infections in the immunocompromised host, although its optimal composition and duration cannot be defined based on the currently available evidence. The role of combination treatment as an early treatment strategy for immunocompromised patients at a high risk of progression to severe disease/persistent shedding requires further evidence from comparison with monotherapy, even though high efficacy was reported for combinations of antivirals plus mAbs in case of previous viral variants.

The triple combination of Remdesivir (GS-441524), Molnupiravir and Ribavirin is highly efficient in inhibiting coronavirus replication in human nasal airway epithelial cell cultures and in a hamster infection model

The use of fixed dose-combinations of antivirals with different mechanisms of action has proven key in the successful treatment of infections with HIV and HCV. For the treatment of infections with SARS-CoV-2 and possible future epi-/pandemic coronaviruses, it will be important to explore the efficacy of combinations of different drugs, in particular to avoid resistance development, such as in patients with immunodeficiencies. This work explores the effect of a combination of 3 broad-spectrum antiviral nucleosides on the replication of coronaviruses. To that end, we made use of primary human airway epithelial cell (HAEC) cultures grown at the air-liquid interface that were infected with the beta coronavirus OC43. We found that the triple combination of GS-441524 (the parent nucleoside of remdesivir), molnupiravir and ribavirin resulted in a more pronounced antiviral efficacy than what could be expected from a purely additive antiviral effect. The potency of this triple combination was next tested in SARS-CoV-2 infected hamsters in a prophylactic setup. To that end, for each of the drugs, intentionally suboptimal or even ineffective doses were selected. Yet, in the lungs of all hamsters that received triple prophylactic therapy (but not in those that received the respective double combinations) no infectious virus was detectable. Our findings indicate that co-administration of approved drugs for the treatment of coronavirus infections should be further explored but also against other families of viruses with epidemic and pandemic potential for which no effective antiviral treatment is available.

Does early combination vs. Monotherapy improve clinical outcomes of clinically extremely vulnerable patients with COVID-19? Results from a retrospective propensity-weighted analysis

BACKGROUND

The potential efficacy of early combination therapy, based on an antiviral plus a monoclonal antibody, for COVID-19 in severely immunocompromised patients is matter of debate.

OBJECTIVES

Our aim was to describe the impact on clinical outcomes of COVID-19 treatments in severely immunocompromised individuals, evaluating differences between a combination and a monotherapy.

METHODS

We included severely immunocompromised outpatients with mild-to-moderate COVID-19 who received an early treatment (either monotherapy with nirmatrelvir/ritonavir or remdesivir or the combination of an antiviral plus sotrovimab). We then assessed differences between the two treatment strategies on three main outcomes (30-day mortality, access to emergency department, hospitalization), separately and as a composite by using a propensity score weighted (PSW) approach.

RESULTS

Eighty one severely immunocompromised patients were included, 39 receiving early combination therapy and 42 receiving monotherapy. No significant difference was observed in the 30-day mortality rate and hospitalization rate between subjects in the two groups, while access to the emergency department following treatment administration was significantly higher in people who received a combination therapy. After applying the PSW, it was observed that combination therapy impacted favourably on the composite outcome, in a statistically significant fashion. In addition, PSW approach for mortality showed that age was the only significant factor influencing the death as stand-alone outcome.

CONCLUSIONS

Early combination therapy showed a favourable impact on a composite outcome (including mortality, hospitalizations and access to emergency department) in severely immunocompromised hosts who were all vaccinated. However, further studies are needed to support our results.

The winding road: Infectious disease considerations for CAR-T and other novel adoptive cellular therapies in the era of COVID-19

Adoptive cellular therapies (ACT) are novel, promising treatments for life-threatening malignancies. In addition to the better known chimeric antigen receptor (CAR) T cells, ACTs include tumor infiltrating lymphocytes (TIL), cancer antigen-specific T cell receptors (TCRs), and CAR-NK (natural killer) cells. In key historic milestones, several adoptive therapies recently received FDA approvals, including 6 CAR-T products for the treatment of hematologic malignancies and the first TIL therapy for the treatment for metastatic melanoma. The rapid pace of clinical trials in the field and the discoveries they provide are ushering in a new era of cancer immunotherapy. However, the potential complications of these therapies are still not fully understood. In particular, patients receiving ACT may be at increased risk for severe infections due to immunocompromise resulting from their underlying malignancies, which are further compounded by the immune derangements that develop in the setting of cellular immunotherapy and/or the preconditioning treatment needed to enhance ACT efficacy. Moreover, these treatments are being readily implemented at a time following the height of the COVID-19 pandemic, and it remains unclear what additional risks these patients may face from SARS-CoV-2 and similar infections. Here, we examine the evidence for infectious complications with emerging adoptive therapies, and provide a focused review of the epidemiology, complications, and clinical management for COVID-19 in CAR-T recipients to understand the risk this disease may pose to recipients of other forms of ACT.

Multiple antimicrobial and immune-modulating activities of cysteamine in infectious diseases

Infectious diseases are a major threat to global health and cause millions of deaths every year, particularly in developing countries. The emergence of multidrug resistance challenges current antimicrobial treatments, inducing uncertainty in therapeutic protocols. New compounds are therefore necessary. A drug repurposing approach could play a critical role in developing new treatments used either alone or in combination with standard therapy regimens. Herein, we focused on cysteamine, an aminothiol endogenously synthesized by human cells during the degradation of coenzyme-A, which is a drug approved for the treatment of nephropathic cystinosis. Cysteamine influences many biological processes due to the presence of the highly reactive thiol group. This review provides an overview of cysteamine-mediated effects on different viruses, bacteria and parasites, with a particular focus on infections caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), Mycobacterium tuberculosis, non-tuberculous mycobacteria (NTM), and Pseudomonas aeruginosa. Evidences for a potential use of cysteamine as a direct antimicrobial agent and/or a host-directed therapy, either alone or in combination with other antimicrobial drugs, are described.

Treatment of chronic COVID-19 with convalescent/postvaccination plasma in patients with hematologic malignancies

Immunocompromised patients are at high risk to fail clearance of SARS-CoV-2. Prolonged COVID-19 constitutes a health risk and a management problem as cancer treatments often have to be disrupted. As SARS-CoV-2 evolves, new variants of concern have emerged that evade available monoclonal antibodies. Moreover, antiviral therapy promotes SARS-CoV-2 escape mutations, particularly in immunocompromised patients. These patients frequently suffer from prolonged infection. No successful treatment has been established for persistent COVID-19 infection. Here, we report on a series of 21 immunocompromised patients with COVID-19-most of them hematologic malignancies-treated with plasma obtained from recently convalescent or vaccinated donors or a combination thereof. Repeated dosing of SARS-CoV-2-antibody-containing plasma could clear SARS-CoV-2 infection in 16 out of 21 immunocompromised patients even if COVID-19-specific treatments failed to induce sustained viral clearance or to improve clinical course of SARS-CoV-2 infection. Ten patients were major responders defined as an increase delta(d)Ct of > = 5 after the first administration of convalescent and/or vaccinated plasma (C/VP). On average, SARS-CoV-2 PCR Ct values increased from a median value of 22.55 (IQR = 19.10-24.25) to a median value of 29.57 (IQR = 27.55-34.63; p = <.0001) in the major response subgroup. Furthermore, when treated a second time with C/VP, even 4 out of 5 of the initial nonresponders showed an increase in Ct-values from a median value of 23.13 (IQR = 17.75-28.05) to a median value of 32.79 (IQR = 31.75-33.75; p = .013). Our results suggest that C/VP could be a feasible treatment of COVID-19 infection in patients with hematologic malignancies who did not respond to antiviral treatment.

Outcomes of Antiviral Retreatment for Immunocompromised Hosts With Prolonged Severe Acute Respiratory Syndrome Coronavirus 2 Polymerase Chain Reaction Positivity: A Multicenter Australian Retrospective Case Series

Outcomes are presented for a multisite retrospective case series, describing a contemporary cohort of 22 immunocompromised patients with persistent coronavirus disease 2019 (COVID-19) polymerase chain reaction positivity who were retreated with antiviral therapy. For those with data available 14 and 30 days after commencement of antiviral therapy, 41% (9 of 22) and 68% (15 of 22), respectively, cleared COVID-19.

Considerations for the development of monoclonal antibodies to address new viral variants in COVID-19

INTRODUCTION

Monoclonal antibody (mAb) therapies proved safe and effective in preventing progression of COVID-19 to hospitalization, but most were eventually defeated by continued viral evolution. mAb combinations and those mAbs that were deliberatively selected to target conserved regions of the SARS-CoV-2 spike protein proved more resilient to viral escape variants as evident by longer clinical useful lives.

AREAS COVERED

We searched PubMed for literature covering the need, development, and use of mAb therapies for COVID-19. As much of humanity now has immunity to SARS-CoV-2, the population at most risk is that of immunocompromised individuals. Hence, there continues to be a need for mAb therapies for immunocompromised patients. However, mAb use in this population carries the risk for selecting mAb-resistant variants, which could pose a public health concern if they disseminate to the general population.

EXPERT OPINION

Going forward, structural knowledge of the interactions of Spike with its cellular receptor has identified several regions that may be good targets for future mAb therapeutics. A focus on designing variant-resistant mAbs together with cocktails that target several epitopes and the use of other variant mitigating strategies such as the concomitant use of small molecule antivirals and polyclonal preparations could extend the clinical usefulness of future preparations.

COVID-19 therapeutics

SUMMARYSince the emergence of COVID-19 in 2020, an unprecedented range of therapeutic options has been studied and deployed. Healthcare providers have multiple treatment approaches to choose from, but efficacy of those approaches often remains controversial or compromised by viral evolution. Uncertainties still persist regarding the best therapies for high-risk patients, and the drug pipeline is suffering fatigue and shortage of funding. In this article, we review the antiviral activity, mechanism of action, pharmacokinetics, and safety of COVID-19 antiviral therapies. Additionally, we summarize the evidence from randomized controlled trials on efficacy and safety of the various COVID-19 antivirals and discuss unmet needs which should be addressed.

Passive immunotherapies for the next influenza pandemic

Influenzavirus is among the most relevant candidates for a next pandemic. We review here the phylogeny of former influenza pandemics, and discuss candidate lineages. After briefly reviewing the other existing antiviral options, we discuss in detail the evidences supporting the efficacy of passive immunotherapies against influenzavirus, with a focus on convalescent plasma.

Emerging anti-spike monoclonal antibodies against SARS-CoV-2

INTRODUCTION

Anti-spike monoclonal antibodies (mAbs) were previously authorized for the prevention and treatment of COVID-19 in immunocompromised patients. However, they are no longer authorized in the U.S. due to their lack of neutralizing activity against current circulating SARS-CoV-2 Omicron variants.

AREAS COVERED

We summarized the available data on emergent mAbs in the early stages of clinical development. Consistent with data on prior mAbs, these novel agents have been well tolerated and demonstrated a good safety profile in early clinical trials. Additionally, many of them have been engineered to ensure prolonged half-life and combined with other mAbs to overcome the potential for emerging resistant mutants. Interestingly, one of these agents has been evaluated using an inhaled route of administration, and another agent is being evaluated for treatment of long COVID.

EXPERT OPINION

Although the available data of novel mAbs holds promise, we anticipate that these agents will face similar challenges encountered by prior authorized agents, including the continued evolution of SARS-CoV-2 and emergence of new escape mutations. Strategies to potentially mitigate this are discussed. Based on prior successful experience, immunocompromised patients will certainly benefit from the utilization of mAbs for the prevention and treatment of COVID-19; thus, we need to design potential interventions to ensure the sustained activity of these agents.

Carbonized aerogel/ZnO-based dispersive solid phase extraction of daclatasvir and sofosbuvir from biological samples prior to liquid chromatography-tandem mass spectrometry

Daclatasvir and sofosbuvir are antiviral medications utilized in the treatment of chronic hepatitis C virus (HCV) infection. Due to their low therapeutic index, careful monitoring is necessary to ensure that the optimal dose is administered. High-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) is an exceptionally sensitive and specific technique for quantifying these drugs within biological matrices. In this study, we developed a novel dispersive solid-phase extraction method employing a carbonized bio aerogel composite with ZnO for efficient extraction of daclatasvir and sofosbuvir from exhaled breath condensate, urine, and plasma samples. The extracted analytes were subsequently subjected to analysis using HPLC-MS/MS. Optimal parameters including pH adjustment, sorbent quantity variation, and elution solvent selection were fine-tuned to achieve maximum recovery efficiency while ensuring selectivity enhancements. The developed method demonstrated broad linearity ranging between 1.2 and 200 ng/mL along with good precision (relative standard deviations ≤6.2 %) and an acceptable coefficient of determination (r2 ≥0.994). These findings establish our proposed method as suitable for reliable drug quantification in clinical samples.

The Role of Convalescent Plasma in COVID-19: A Conclusive Post-Pandemic Review

COVID-19 convalescent plasma (CCP) has represented the frontline response to the COVID-19 pandemic, largely because of encouraging historical evidences in previous pandemics, biological plausibility, and the initial unavailability of targeted antivirals. Unfortunately, investigator-initiated randomized clinical trials in 2020, launched during a stressful pandemic peak, were designed mostly at addressing the main unmet need, i.e., treating critically ill hospitalized patients who were unlikely to benefit from any antiviral therapy. The failure of most of these drugs, in combination with the lack of any sponsor, led to the false belief that convalescent plasma was useless. With the relaxing pandemic stages, evidences have instead mounted that, when administered properly (i.e., within 5 days from onset of symptoms and at high titers of neutralizing antibodies), CCP is as effective as other antivirals at preventing disease progression in outpatients, and also reduces mortality in hospitalized patients. Recently, the focus of clinical use has been on immunosuppressed patients with persistent seronegativity and infection, where a randomized clinical trial has shown a reduction in mortality. Lessons learnt during the COVID-19 pandemic will be of utmost importance for future pandemics.