Novel antivirals for severe enterovirus infection in immunocompromised hosts; A case series
Authors: Andrea Meinhardt, Liam Reilly, Marios Kaliakatsos, Khaled Abdel-Aziz, Sondus Alsharidah, Istvan Bodi, Claire Booth, Kritika Chetty, Jennifer Evans, Laura Ferreras-Antolín, Susannah Froude, Clare M. Galtrey, Suba Guruprasad, Robert D. Hadden, Jane Hassell, Heikki Hyöty, Alexandra Y. Kreins, Jutta E. Laiho, David M. Lowe, Michael P. Lunn, Kshitij Mankad, Siske Struik, Elizabeth Whittaker, Austen Worth, Patrick Yong, Liqun Zhang, Judith Breuer, Seilesh Kadambari
Journal: Journal of Infection (2024)

•Enteroviruses can cause significant morbidity and mortality in immunocompromised.•Serial tests in multiple compartments may be necessary to identify Enterovirus.•Metagenomics on brain biopsy may be justified when conventional testing is negative.•Early combination antiviral treatments can improve outcomes in immunocompromised.•Antiviral therapy acts as bridging therapy until immune reconstitution. Previously in this Journal, it was pointed out that novel antiviral treatments are badly needed for severe enterovirus infections1Abzug M.J. The enteroviruses: Problems in need of treatments.J infect. 2014 Jan; 68: 108-114https://doi.org/10.1016/j.jinf.2013.09.020Abstract Full Text Full Text PDF PubMed Scopus (98) Google Scholar. We describe eight immunocompromised individuals who received antiviral combinations with novel and repurposed agents in UK (Table 1).Table 1Detailed description of eight patients with severe enterovirus infection.Abbr.: abnormal values in blue; AA aplastic anaemia, aGvHD acute GvHD, ALT Alanine Aminotransferase, AZA azathioprine, BD twice a day, CSF cerebrospinal fluid, CT computer tomography, ct cycle threshold, d day(s), DIC disseminated intravascular coagulation, dx diagnosis, EBV Epstein-Barr-Virus, ECHO echocardiography, EF ejection fraction, EV enterovirus, F favipiravir, FLAIR fluid-attenuated inversion recovery, FU follow up, GvHD graft versus host disease, HSCT haematopoietic stem cell transplantation, ICU intensive care unit, Ig immunoglobulin, inf. infection, ITP immune thrombocytopenia, IVIG intravenous immunoglobulin G, lymph lymphocytes, m month(s), max. maximal, MHC major histocompatibility complex, MMF Mycophenolate mofetil, MRI magnet resonance imaging, MS multiple sclerosis, n normal, N nitazoxanide, n.a. not available, NEC necrotizing enterocolitis, neg. negative, n.m. not measured, NPA nasopharyngeal aspirate, OD once daily, P pocapavir, pos. positive, R ribavirin, rbc tx red blood cell transfusion, Ritux Rituximab, R-ODS Rasch-built overall disability score, rect. rectal, SCID severe combined immunodeficiency, TDS three times a day, thr. throat, w week(s), WCC white cell count, w/o without, y year(s), ↑ increased, ↓ reduced, *published previously (3), aanti-Ro, -La pos., bRegulatory Factor X Associated Ankyrin Containing Protein (RFXANK) mutation, cskin and gut, dInterleukin 2 Receptor Subunit Gamma (IL2RG) mutation, e10/10 Matched family donor, condition Anti-thymocyte globulin, Fludarabine/Treosulfan/ Thiotepa, GvHD prophylaxis: Cyclosporin, fdonor: mother, condition Anti-thymocyte globulin, Fludarabine, Cyclophosphamide, total body irradiation; GvHD prophylaxis: MMF+ Sirolimus gtreatment for acute skin and gut GvHD, has EBV treatment, icondition low-dose Busulfan jmetagenomics on brain biopsy also pos., kongoing, l2 g/kg/28d for the first 3m, m20mg OD, increased over 14d to 60 mg OD, nstopped at favipiravir start, othen subcutaneous 0.125 g/kg/7d, >4m, p800mg BD on day 1, q1800 mg BD on day 1, rreduced to 1 g/kg/28d for 3m, sinitially 2.5mg OD, t1200mg on day 1 Open table in a new tab Abbr.: abnormal values in blue; AA aplastic anaemia, aGvHD acute GvHD, ALT Alanine Aminotransferase, AZA azathioprine, BD twice a day, CSF cerebrospinal fluid, CT computer tomography, ct cycle threshold, d day(s), DIC disseminated intravascular coagulation, dx diagnosis, EBV Epstein-Barr-Virus, ECHO echocardiography, EF ejection fraction, EV enterovirus, F favipiravir, FLAIR fluid-attenuated inversion recovery, FU follow up, GvHD graft versus host disease, HSCT haematopoietic stem cell transplantation, ICU intensive care unit, Ig immunoglobulin, inf. infection, ITP immune thrombocytopenia, IVIG intravenous immunoglobulin G, lymph lymphocytes, m month(s), max. maximal, MHC major histocompatibility complex, MMF Mycophenolate mofetil, MRI magnet resonance imaging, MS multiple sclerosis, n normal, N nitazoxanide, n.a. not available, NEC necrotizing enterocolitis, neg. negative, n.m. not measured, NPA nasopharyngeal aspirate, OD once daily, P pocapavir, pos. positive, R ribavirin, rbc tx red blood cell transfusion, Ritux Rituximab, R-ODS Rasch-built overall disability score, rect. rectal, SCID severe combined immunodeficiency, TDS three times a day, thr. throat, w week(s), WCC white cell count, w/o without, y year(s), ↑ increased, ↓ reduced, *published previously (3), aanti-Ro, -La pos., bRegulatory Factor X Associated Ankyrin Containing Protein (RFXANK) mutation, cskin and gut, dInterleukin 2 Receptor Subunit Gamma (IL2RG) mutation, e10/10 Matched family donor, condition Anti-thymocyte globulin, Fludarabine/Treosulfan/ Thiotepa, GvHD prophylaxis: Cyclosporin, fdonor: mother, condition Anti-thymocyte globulin, Fludarabine, Cyclophosphamide, total body irradiation; GvHD prophylaxis: MMF+ Sirolimus gtreatment for acute skin and gut GvHD, has EBV treatment, icondition low-dose Busulfan jmetagenomics on brain biopsy also pos., kongoing, l2 g/kg/28d for the first 3m, m20mg OD, increased over 14d to 60 mg OD, nstopped at favipiravir start, othen subcutaneous 0.125 g/kg/7d, >4m, p800mg BD on day 1, q1800 mg BD on day 1, rreduced to 1 g/kg/28d for 3m, sinitially 2.5mg OD, t1200mg on day 1 Enteroviruses (EV) are RNA viruses that cause self-limiting or asymptomatic infection in immunocompetent individuals. However sepsis-like syndrome, chronic neurological disease, and mortality may occur in neonates and immunocompromised patients, particularly with antibody deficiencies1Abzug M.J. The enteroviruses: Problems in need of treatments.J infect. 2014 Jan; 68: 108-114https://doi.org/10.1016/j.jinf.2013.09.020Abstract Full Text Full Text PDF PubMed Scopus (98) Google Scholar, 2Copelyn J. Hincks J.R. Wilmshurst J.M. Petersen W. Howard W. Jallow S. et al.Clearance of Immunodeficiency-associated Vaccine-derived Poliovirus Infection with Pocapavir.Pediatr Infect Dis J [Internet]. 2020; 39 (Available from: 〈https://journals.lww.com/pidj/Fulltext/2020/05000/Clearance_of_Immunodeficiency_associated.14.aspx〉)https://doi.org/10.1097/INF.0000000000002584Crossref Scopus (8) Google Scholar. There are still no licenced agents to treat severe EV disease and to our knowledge no phase 3 trials are in progress. Antiviral agents were used on ad hoc basis in this case series. Patients were retrospectively identified by clinicians providing expert advice on the use of novel antivirals. Patients or their legal guardian gave written consent for publication through their treating physician. A standardized data set was supplied for every patient. One patient has been previously reported3Chetty K. Cheng I. Kaliakatsos M. Gonzalez-Granado L.I. Klapsa D. Martin J. et al.Case report: Novel treatment regimen for enterovirus encephalitis in SCID.Front Immunol. 2022 Sep; 13https://doi.org/10.3389/fimmu.2022.930031Crossref Scopus (3) Google Scholar. Patients were aged between 5 days and 34 years and presented with subacute meningoencephalitis (6/8) or sepsis (2/8). Patients 1-4 were moderately immunocompromised due to prematurity or immunosuppressive therapy (IST). Patients 5-8 were profoundly immunocompromised due to haematopoietic stem cell transplant (HSCT), gene therapy or IST with an underlying primary immunodeficiency (PID). Three patients initially received steroids for a presumed inflammatory condition, all subsequently deteriorated. At presentation, fever (5/8), hypothermia (1/8) and weight loss (1/8) with organ dysfunction were reported. Neurological features were common and wide ranging, particularly lethargy or drowsiness (4/8) and brain stem signs (4/8). Both preterm infants had a sepsis-like syndrome. EV diagnosis was made 3 days to 10 months after symptom onset. Lumbar puncture (LP) was performed in 6/8 patients. EV CSF PCR was positive in all 6 cases, although in patients 5 and 6 EV PCR was first positive on the third LP. In patient 5, in whom EV PCR was only positive at high cycle threshold, Coxsackievirus B4 was clearly demonstrated on brain biopsy through metagenomics. Here, metagenomic sequencing was shown to identify EV infection where conventional PCRs had been unsuccessful4Atkinson L. Lee J.C. Lennon A. Shah D. Storey N. Morfopoulou S. et al.Untargeted metagenomics protocol for the diagnosis of infection from CSF and tissue from sterile sites.Heliyon. 2023 Sep 9; 9https://doi.org/10.1016/j.heliyon.2023.e19854Abstract Full Text Full Text PDF Scopus (0) Google Scholar, 5Brown J.R. Bharucha T. Breuer J. Encephalitis diagnosis using metagenomics: application of next generation sequencing for undiagnosed cases.J Infect. 2018 Mar; 76: 225-240https://doi.org/10.1016/j.jinf.2017.12.014Abstract Full Text Full Text PDF PubMed Scopus (173) Google Scholar. EV protein was confirmed by immunohistochemistry staining in several neuron-like cells (Fig. 1). MRI brain demonstrated typical EV changes in the thalami, cerebellum, pons, periventricular white matter and basal ganglia in 4/66Abdelgawad M.S. El-Nekidy A.E.A. Abouyoussef R.A.M. El-Fatary A. MRI findings of enteroviral encephalomyelitis.Egypt J Radiol Nucl Med. 2016 Sep 1; 47: 1031-1036https://doi.org/10.1016/j.ejrnm.2016.05.004Abstract Full Text Full Text PDF Scopus (7) Google Scholar, but normal findings were seen in 2/6 despite clinical evidence of neurological dysfunction and abnormal CSF. B and/or T cell lymphopenia was found in 6/6 patients and hypogammaglobulinemia in 5/6 at time of EV diagnosis. All patients received high dose IVIG (1-4 g/kg/month). Half initially received IVIG alone or with fluoxetine, with other novel antivirals added later. The others started treatment with IVIG and novel antivirals or ribavirin at the same time. Pocapavir (5/8), fluoxetine (6/8), favipiravir (5/8), nitazoxanide (4/8), and ribavirin (2/8) were used in varying combinations. Novel antivirals were started in four patients within 12 days of symptom onset. The interval for patients four, five and six was 1.2 – 3 months, and 52 months for patient three. The duration of therapy varied from 14 days to more than 4 years in patient three who remains persistently EV CSF positive. One patient died before EV CSF clearance. All others cleared EV within 2-17 weeks. No severe adverse effects were reported. Initial therapy with IVIG alone was associated with deterioration in 2/3 (patient 4 and 6) but significant improvement in 1/3 (patient 7). Complete recovery without neurological sequelae was seen in 2/8 patients. In both instances, diagnosis of EV infection and initiation of antiviral treatment occurred within 12 days of symptom onset. Significant clinical improvement was observed in 4/8. Two patients died: one from multiorgan failure on day 5 of EV infection, the other 18 months after symptom onset due to severe neurological deterioration despite clearance of EV on day 13 after starting Nitazoxanide. This small case series provides support for IVIG and early combination antiviral therapy in significantly immunosuppressed individuals with severe EV disease. In our cohort, prompt diagnosis and therapy were associated with better outcomes. We used novel antivirals that are known to have in vitro activity against EV. Due to the risk of drug resistance, pocapavir2Copelyn J. Hincks J.R. Wilmshurst J.M. Petersen W. Howard W. Jallow S. et al.Clearance of Immunodeficiency-associated Vaccine-derived Poliovirus Infection with Pocapavir.Pediatr Infect Dis J [Internet]. 2020; 39 (Available from: 〈https://journals.lww.com/pidj/Fulltext/2020/05000/Clearance_of_Immunodeficiency_associated.14.aspx〉)https://doi.org/10.1097/INF.0000000000002584Crossref Scopus (8) Google Scholar and fluoxetine7Bauer L. Manganaro R. Zonsics B. Strating J.R.P.M. El Kazzi P. Lorenzo Lopez M. et al.Fluoxetine Inhibits Enterovirus Replication by Targeting the Viral 2C Protein in a Stereospecific Manner.ACS Infect Dis. 2019 Sep 13; 5: 1609-1623https://doi.org/10.1021/acsinfecdis.9b00179Crossref Scopus (46) Google Scholar were used in combination, except in both preterm neonates where pharmacokinetic/pharmacodynamic data are scarce. Pocapavir inhibits EV capsid disassembly, preventing release of viral RNA into the host cell. Successful pocapavir treatment has been reported in neonatal EV myocarditis, vaccine-derived poliovirus infection in X-linked agammaglobulinemia and EV meningoencephalitis2Copelyn J. Hincks J.R. Wilmshurst J.M. Petersen W. Howard W. Jallow S. et al.Clearance of Immunodeficiency-associated Vaccine-derived Poliovirus Infection with Pocapavir.Pediatr Infect Dis J [Internet]. 2020; 39 (Available from: 〈https://journals.lww.com/pidj/Fulltext/2020/05000/Clearance_of_Immunodeficiency_associated.14.aspx〉)https://doi.org/10.1097/INF.0000000000002584Crossref Scopus (8) Google Scholar, 8Collett M.S. Hincks J.R. Benschop K. Duizer E. van der Avoort H. Rhoden E. et al.Antiviral Activity of Pocapavir in a Randomized, Blinded, Placebo-Controlled Human Oral Poliovirus Vaccine Challenge Model.J Infect Dis. 2017 Feb 1; 215: 335-343https://doi.org/10.1093/infdis/jiw542Crossref PubMed Scopus (50) Google Scholar. Fluoxetine, a selective serotonin reuptake inhibitor, specifically inhibits EV replication by binding the viral 2 C protein7Bauer L. Manganaro R. Zonsics B. Strating J.R.P.M. El Kazzi P. Lorenzo Lopez M. et al.Fluoxetine Inhibits Enterovirus Replication by Targeting the Viral 2C Protein in a Stereospecific Manner.ACS Infect Dis. 2019 Sep 13; 5: 1609-1623https://doi.org/10.1021/acsinfecdis.9b00179Crossref Scopus (46) Google Scholar. Reports of efficacy are mixed with one retrospective case series finding little benefit in children with EV acute flaccid myelitis9Messacar K. Sillau S. Hopkins S.E. Otten C. Wilson-Murphy M. Wong B. et al.Safety, tolerability, and efficacy of fluoxetine as an antiviral for acute flaccid myelitis.Neurology. 2019 Apr 30; 92: e2118-e2126https://doi.org/10.1212/WNL.0000000000006670Crossref PubMed Scopus (47) Google Scholar. Favipiravir has broad spectrum anti RNA dependent RNA polymerase activity, including against EV10Wang Y. Li G. Yuan S. Gao Q. Lan K. Altmeyer R. et al.In Vitro Assessment of Combinations of Enterovirus Inhibitors against Enterovirus 71.Antimicrob Agents Chemother. 2016 Aug 22; 60: 5357-5367https://doi.org/10.1128/AAC.01073-16Crossref Scopus (32) Google Scholar. Delay in initiating novel antivirals occurred in half of our cohort, primarily due to challenges of diagnosing EV infection. These findings should encourage clinicians to submit repeated samples from multiple biological compartments to increase the yield of EV detection. Invasive tissue sampling and testing using metagenomics should be considered if diagnostic uncertainty remains. There is a lack of robust data to justify routine use of novel and combination antiviral therapies in EV infection. Our case series, despite limitations including a small and heterogeneous cohort, retrospective observational design, and limited follow-up, suggests benefit of early combination antiviral therapy in heavily immunocompromised patients with severe EV disease. A high degree of suspicion for enteroviral encephalitis in deteriorating immunocompromised patients and early diagnosis with low threshold for brain biopsy where CSF PCR is inconclusive are paramount. Case by case discussion with a multidisciplinary team experienced in novel antivirals is warranted. Clearance of EV is likely to depend on reconstitution of immune recovery with antivirals acting as a bridging therapy in immunocompromised patients. Further descriptive studies, registry data enabling longitudinal follow up and ultimately pragmatically designed RCTs are necessary to better define the efficacy, safety, and optimal combination of antiviral regimens for serious enteroviral infection. Conceptualization: A.M., L.R., J.B., S.K. Acquisition of data and treatment of included patients: M.K., K.A.-A., S.A., L.F.A., I.B., C.B., K.C., J.E., S.F., C.M.G., S.G., R.D.H., J.H., H.H., A.Y.K., J.E.L., D.M.L., M.P.L., K.M., S.S., E.W., A.W., P.Y., L.Z., J.B., S.K. Expert committee for treatment recommendations: M.K., D.M.L., J.B., S.K. Writing original draft (lead): A.M., L.R., J.B., S.K., Writing original draft (equal): M.K., K.A.-A., S.A., L.F.A., I.B., C.B., K.C., J.E., S.F., C.M.G., S.G., R.D.H., J.H., H.H., A.Y.K., J.E.L., D.M.L., M.P.L., K.M., S.S., E.W., A.W., P.Y., L.Z. This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.