Isoprinosine affects serum cytokine levels in healthy adults

Isoprinosine as a foot-and-mouth disease vaccine adjuvant elicits robust host defense against viral infection through immunomodulation

Background

Commercial foot-and-mouth disease (FMD) vaccines have limitations, such as local side effects, periodic vaccinations, and weak host defenses. To overcome these limitations, we developed a novel FMD vaccine by combining an inactivated FMD viral antigen with the small molecule isoprinosine, which served as an adjuvant (immunomodulator).

Method

We evaluated the innate and adaptive immune responses elicited by the novel FMD vaccine involved both in vitro and in vivo using mice and pigs.

Results

We demonstrated isoprinosine-mediated early, mid-term, and long-term immunity through in vitro and in vivo studies and complete host defense against FMD virus (FMDV) infection through challenge experiments in mice and pigs. We also elucidated that isoprinosine induces innate and adaptive (cellular and humoral) immunity via promoting the expression of immunoregulatory gene such as pattern recognition receptors [PRRs; retinoic acid-inducible gene (RIG)-I and toll like receptor (TLR)9], transcription factors [T-box transcription factor (TBX)21, eomesodermin (EOMES), and nuclear factor kappa B (NF-kB)], cytokines [interleukin (IL)-12p40, IL-23p19, IL-23R, and IL-17A)], and immune cell core receptors [cluster of differentiation (CD)80, CD86, CD28, CD19, CD21, and CD81] in pigs.

Conclusion

These findings present an attractive strategy for constructing novel FMD vaccines and other difficult-to-control livestock virus vaccine formulations based on isoprinosine induced immunomodulatory functions.

[Herpangina. Clinical case]

Enterovirus infections are a group of acute infectious diseases caused by enteroviruses (including Coxsackie A and B viruses, ECHO viruses), which clinically present symptoms of damage to the central nervous system, cardiovascular system, gastrointestinal tract, muscular system, mucous membranes and skin, fever. This article presents a clinical case of patient L., 12 years old, who admitted to an otorhinolaryngologist with clinical manifestations of herpangina. The diagnosis was confirmed by PCR. The patient was prescribed, adequate rehydration, diet with the exclusion of salty, spicy and fried foods, restriction of physical activity, exclusion of thermal procedures, Benzydamine Spray (Oralsept) 0.255 mg/dose, 6 doses 3 times/day, topically, on demand and inosine pranobex (Groprinosin) in a daily dose of 50 mg/kg of body weight: 1 tablet 500 mg 4 times a day for 7 days (at the rate of 1 tablet of 500 mg per 10 kg of body weight; for a patient weighing 41 kg - 4 tablets per day). On the 10th day from the onset of the disease, the docter noted a complete regression of clinical symptoms and the patient was discharged with recovery.

Inosine Pranobex Deserves Attention as a Potential Immunomodulator to Achieve Early Alteration of the COVID-19 Disease Course

Since its licensing in 1971, the synthetic compound inosine pranobex has been effectively combating viral infections, including herpes zoster, varicella, measles, and infections caused by the herpes simplex virus, human papillomavirus, Epstein-Barr virus, cytomegalovirus, and respiratory viruses. With the emergence of SARS-CoV-2, new and existing drugs have been intensively evaluated for their potential as COVID-19 medication. Due to its potent immunomodulatory properties, inosine pranobex, an orally administered drug with pleiotropic effects, can, during early treatment, alter the course of the disease. We describe the action of inosine pranobex in the body and give an overview of existing evidence collected to support further efforts to study this drug in a rigorous clinical trial setup.

Mechanisms of Immunothrombosis by SARS-CoV-2

SARS-CoV-2 contains certain molecules that are related to the presence of immunothrombosis. Here, we review the pathogen and damage-associated molecular patterns. We also study the imbalance of different molecules participating in immunothrombosis, such as tissue factor, factors of the contact system, histones, and the role of cells, such as endothelial cells, platelets, and neutrophil extracellular traps. Regarding the pathogenetic mechanism, we discuss clinical trials, case-control studies, comparative and translational studies, and observational studies of regulatory or inhibitory molecules, more specifically, extracellular DNA and RNA, histones, sensors for RNA and DNA, as well as heparin and heparinoids. Overall, it appears that a network of cells and molecules identified in this axis is simultaneously but differentially affecting patients at different stages of COVID-19, and this is characterized by endothelial damage, microthrombosis, and inflammation.

A Review on Inosine Pranobex Immunotherapy for Cervical HPV-Positive Patients

The purpose of this review was to examine and summarize data for inosine pranobex (IP) immunotherapy in cervical HPV-positive patients. Persistent or recurring cervical human papillomavirus (HPV) infection is a major cause of cervical cancer. Self-clearance and blocking of cervical HPV infection depend on the status of the host immune system. Immunotherapy helps accelerate elimination of the infection. Host immunity is involved in the development of HPV infection. Several mechanisms of interaction between the virus and the immune system have been revealed; however, the mechanisms have not been completely elucidated. A properly functioning immune system impedes HPV progress and helps clear the pathogen from the body. IP has antiviral efficacy because it modulates both cellular and humoral immunities. IP has been on the market since 1971. Nevertheless, it has seldom been administered to treat cervical HPV infections. In this review, Google Scholar, PubMed/MEDLINE, Scopus, Cochrane Library, and Research Gate were searched for the period 1971–2021. Prospective controlled trials, observational and retrospective studies, and meta-analysis and reviews on immunotherapy against HPV cervical infection were explored. Prior studies showed strong clinical efficacy of combined and standalone IP therapy in reversing HPV-induced changes in the cervix, preventing disease progression, and clearing the pathogen. IP treatment enhanced host antiviral activity against HPV, delayed or stopped cervical oncogenesis, and rapidly removed HPV from the body.

Inosine Pranobex: A Key Player in the Game Against a Wide Range of Viral Infections and Non-Infectious Diseases

Inosine pranobex (IP), commonly known as inosine acedoben dimepranol, isoprinosine and methisoprinol, has been proven to positively impact the host’s immune system, by enhancing T-cell lymphocyte proliferation and activity of natural killer cells, increasing levels of pro-inflammatory cytokines, and thereby restoring deficient responses in immunosuppressed patients. At the same time, it has been shown that it can affect viral RNA levels and hence inhibit growth of several viruses. Due to its immunomodulatory and antiviral properties, and its safety profile, it has been widely used since 1971 against viral infections and diseases, among which subacute sclerosis panencephalitis, herpes simplex virus, human papilloma virus, human immunodeficiency virus, influenza and acute respiratory infections, cytomegalovirus and Epstein–Barr virus infections. Following an analysis of almost five decades of scientific literature since its original approval, we here summarize in vivo and in vitro studies manifesting the means in which IP impacts the host’s immune system. We also provide a synopsis of therapeutic trials in the majority of which IP was found to have a beneficial effect. Lastly, positive results from limited studies, suggesting the putative future use of IP in new therapeutic indications are briefly described. In order to support use of IP against viral infections apart from those already approved, and to establish its use in clinical practice, further well-designed and executed trials are warranted.

Funding: Ewopharma International.

Genotoxicity and Mutagenicity of Inosine Pranobex

Introduction

Inosine pranobex (Methisoprinol, ISO, Isoprinosine) is an immuno-modulatory antiviral drug that has been licensed since 1971 in several countries worldwide. In humans, the drug is approved for the treatment of viral infections, and it might also have therapeutic use in animals. The aims of the presented work were to investigate the genotoxicity of inosine pranobex on BALB/3T3 clone A1 and HepG2 cell lines and to elucidate its mutagenicity using the Ames test.

Material and Methods

The BALB/3T3 clone A1 and HepG2 cells were incubated with inosine pranobex at concentrations from 0.1 to 1,000 μg/mL. The genotoxicity was determined by comet and micronucleus assays, and the mutagenicity was determined by Ames assay.

Results

Inosine pranobex did not induce a significant dose-related increase in the number of comets or micronuclei in BALB/3T3 clone A1 and HepG2 cells. Moreover, based on the results of the Ames test, it was concluded that inosine pranobex is not mutagenic in the Salmonella typhimurium reverse mutation assay.

Conclusion

Based on the results of a comet assay, micronucleus assay, and Ames test, it was concluded that inosine pranobex is neither genotoxic nor mutagenic.

Influence of Inosine Pranobex on Cell Viability in Normal Fibroblasts and Liver Cancer Cells

Introduction

Inosine pranobex (Isoprinosine) stimulates cell-mediated immune responses to viral infections in humans and might have also therapeutic use in animals. The aim of this study was to compare three in vitro cytotoxicity assays on mouse embryo fibroblasts and liver cancer cells and determine their ability to detect early cytotoxic effects for inosine pranobex.

Material and Methods

BALB/3T3 clone A31and HepG2 cells were incubated with inosine pranobex at concentrations from 0.1 to 1,000 μg/mL. Cell viability was determined with the MTT reduction, the LHD release, and the NRU tests.

Results

A decrease in the cell viability was observed after incubating the BALB/3T3 clone A31and HepG2 cells with inosine pranobex.

Conclusions

Based on the cytotoxicity endpoints measured in these investigations in BALB/3T3 clone A31cells, it can be concluded that the cell membrane may be the first part of the cell to be affected by inosine pranobex. The disintegration of lysosomes and mitochondria follows mitochondria damage. In HepG2 cells likewise, the cell membrane may be the first part of the cell to be affected by inosine pranobex. Also in liver cancer cells, the disintegration of mitochondria (assessed with the MTT reduction assay) and next of lysosomes (assessed with the NRU assay) follows mitochondria damage.

Evaluation of isoprinosine to be repurposed as an adjunct anti-tuberculosis chemotherapy

Isoprinosine (Inos) or immunovir is a synthetic purine derivative with immune-modulatory and antiviral properties. The drug shows apparent in vivo enhancement of host immune responses by inducing pro-inflammatory cytokines and rapid proliferation of T-cell subsets. Strikingly, the cytokines induced by Inos also play crucial roles in providing immune resistance against Mycobacterium tuberculosis (Mtb). Inos has been licensed for several antiviral diseases; however, its efficacy against Mtb has not been tested yet. Since Mtb subverts the host immune system to survive within the host. Therefore, we hypothesized that the immune-stimulatory properties of Inos can be explored as an adjunct therapy for the management of tuberculosis. We have also outlined a systematic direction of study to evaluate if Inos could be repurposed for tuberculosis. The in vivo studies for therapeutic evaluation of Inos alone or in combination with the first line anti-TB drugs in a suitable TB disease model would provide a clearer picture of its utility as a host-directed anti-TB drug and may endow us with a new application of an existing drug to combat tuberculosis.

Inosine Acedoben Dimepranol promotes an early and sustained increase in the natural killer cell component of circulating lymphocytes: A clinical trial supporting anti-viral indications

Inosine Acedoben Dimepranol (IAD), licensed for the treatment of cell-mediated immune deficiencies associated with viral infections, has been reported to impact a variety of immune parameters both in vitro and in vivo. Here we report the results from a clinical trial where multiple lymphocyte subsets - CD19+ B cells, CD3+ T cells, CD4+ T-helper cells, FoxP3^hi/CD25^hi/CD127^lo regulatory T cells (Tregs), CD3-/CD56+ NK cells, and CD3+/CD56+ NKT cells - were, together with serum immunoglobulins and IgG subclasses, followed during 14days of IAD administration to ten healthy volunteers; these selected from 27 individuals pre-screened in vitro for their capacity to respond to IAD as gauged by increases in the percentage of Treg and/or NKT cells arising in PHA-stimulated cultures. While a transient spike and dip in Treg and T-helper fractions, respectively, was noted, the outstanding consequence of IAD administration (1g po, qds) was an early and durable rise in NK cells. For half the cohort, NK cells increased as a percentage of total peripheral blood lymphocytes within 1.5h of receiving drug. By Day 5, all but one of the volunteers displayed higher NK cell percentages, such elevation - effectively a doubling or greater - being maintained at termination of study. The IAD-induced populations were as replete in Granzyme A and Perforin as basal NK cells. The novel finding of IAD boosting phenotypically competent NK numbers in healthy individuals supports the drug's indicated benefit in conditions associated with viral infection and reinforces the potential for uplift where immune performance may be compromised.

Inosine pranobex is safe and effective for the treatment of subjects with confirmed acute respiratory viral infections: analysis and subgroup analysis from a Phase 4, randomised, placebo-controlled, double-blind study

BACKGROUND

Inosine pranobex (Isoprinosine®) is an immunomodulatory drug approved in several countries for the treatment of viral infections. This study compared the efficacy and safety of inosine pranobex versus placebo in subjects with clinically diagnosed influenza-like illness, including subjects with laboratory-confirmed acute respiratory viral infections. Subgroup analyses evaluated the efficacy of inosine pranobex compared to placebo in otherwise healthy (without related ongoing disease) subjects that were less than 50 years of age and healthy subjects that were at least 50 years of age. The effect of body mass index (BMI) was evaluated in subjects less than 50 years of age.

METHODS

A total of 463 subjects were randomly assigned to receive inosine pranobex (n = 231) or placebo (n = 232) in this Phase 4, randomised, double-blind, multicentre study. The primary efficacy endpoint was time to resolution of all influenza-like symptoms present at baseline to none. Safety was evaluated through analysis of adverse events, vital signs, and physical examinations.

RESULTS

The difference in time to resolution of all influenza-like symptoms between treatment groups was not statistically significant but showed a faster improvement in subjects in the inosine pranobex group versus those in the placebo group - Hazard Ratio = 1.175; (95 % CI: 0.806-1.714). P-value = 0.324. In the subgroup analysis for subjects less than 50 years of age, statistically significant differences in time to resolution of influenza-like symptoms that favoured the inosine pranobex group over the placebo group were observed in those without related ongoing disease and those who were non-obese (BMI <30 kg/m²). The differences between the inosine pranobex and placebo groups in subjects at least 50 years of age without related ongoing disease and in subjects less than 50 years of age who were obese (BMI ≥30 kg/m²) were not statistically significant. Inosine pranobex was generally well tolerated, and no deaths were reported.

CONCLUSIONS

The study results indicate the safety of inosine pranobex for the treatment of subjects with confirmed acute respiratory viral infections and confirm the efficacy of inosine pranobex versus placebo in healthy non-obese subjects less than 50 years of age with clinically diagnosed influenza-like illnesses.

TRIAL REGISTRATION

EWO-ISO-2014/1, EudraCT 2014-001863-11 ; Date of registration: 29 APR 2014; Detail information web link: https://www.clinicaltrialsregister.eu/ctr-search/trial/2014-001863-11/results.

Inhibition of adenovirus multiplication by inosine pranobex and interferon α in vitro

There are no specific antivirals designed for adenoviral infections. Due to many cases of adenovirus infections worldwide, epidemic nature of some types of adenoviruses, and growing number of patients with severe adenoviral infections resulting from dysfunction the immune system, the need for searching an effective and safe therapy is increasing. Inosine pranobex exerts antiviral effects which are both direct and secondary to immunomodulatory activity. In the present study we evaluated in vitro effect of inosine pranobex and interferon α (IFN-α) on replication of HAdV-2 and HAdV-5. The effectiveness of inosine pranobex under these conditions has not been previously reported. In conducted study we reported that inosine pranobex reduced the titer of infectious HAdV-2 and HAdV-5 in vitro. Higher concentrations of IP strongly inhibited multiplication of viruses. Combination of inosine pranobex and IFN-α display higher efficacy than either treatment alone and suggest that both agents may increase therapeutic effectiveness without augmenting toxic effects. Combination index calculations showed that inosine pranobex and INF-α synergistically inhibit HAdV-2 and HAdV-5 titers in A549 cells.

Multicenter randomized study of inosine pranobex versus acyclovir in the treatment of recurrent herpes labialis and recurrent herpes genitalis in Chinese patients

The objective of the study is to evaluate the efficacy and safety of oral inosine pranobex as compared with acyclovir in the treatment of recurrent herpes labialis (RHL) and recurrent herpes genitalis (RHG). A multicenter double-blind, double-dummy, randomized, controlled, parallel group trial was conducted in 144 patients with RHL and 144 RHG. Patients were assigned to treatment in one of two groups: (i) inosine pranobex group (active inosine pranobex, 1 g four times daily, and acyclovir placebo); or (ii) acyclovir group (active acyclovir, 200 mg five times daily, and inosine pranobex placebo). The total symptom score (TSS) of patients with RHL did not differ in the inosine pranobex and acyclovir group on the 3rd or 7th day of treatment. There was also no difference in the efficacy rates between the two groups. No difference of TSS was observed between patients with RHG taking inosine pranobex and acyclovir on days 3 or 5 of the treatment, respectively. The short-term clinical recurrence rate of RHG at 3-month follow-up was much lower in the inosine pranobex group than acyclovir group. The incidence of hyperuricemia was higher in the inosine pranobex group than acyclovir group. In conclusion, inosine pranobex was as effective as acyclovir in treating RHL and RHG with significantly greater reduction of the short-term recurrence rate of herpes genitalis at 3-month follow up. Long-term recurrence rates at 6 months or longer remain to be determined. Hyperuricemia should be monitored during the treatment.