Tolerance of one-month intranasal interferon

Interferon-based agents for current and future viral respiratory infections: A scoping literature review of human studies

The interferon (IFN) system is a potent line of defense against viral infections. IFN-based agents already tested may be of use in COVID-19 or future viral respiratory outbreaks. Here we review the comparative efficacy, safety/tolerability, and future potential of IFN-based therapeutics. We reviewed human studies in which IFN or IFN pathway-interacting agents were used for viral respiratory infections. We identified 977 articles, of which 194 were included for full-text review. Of these, we deemed 35 articles to be relevant. The use of IFN-based agents for pre-exposure prophylaxis (n = 19) and treatment (n = 15) were most common, with intranasal (n = 22) as the most common route. We found IFN-α (n = 23) was used most often, and rhinovirus (n = 14) was the most common causative agent. Studies demonstrated mixed efficacy but generally positive safety and tolerability. Host-directed therapies, such as IFN or IFN inducers, are worthy of additional research to target viral respiratory infections lacking direct-acting antivirals.

A randomized controlled trial of low-dose recombinant human interferons alpha-2b nasal spray to prevent acute viral respiratory infections in military recruits

The military population has a high disease burden of acute viral respiratory infections in China. To assess the efficacy and safety of a low-dose recombinant human interferon α-2b (rIFNα-2b) nasal spray in preventing acute viral respiratory infections in military population, we performed this randomized controlled trial. The results showed that application of the rIFNα-2b nasal spray had the benefits in prevention of infections caused by influenza A virus, influenza B virus parainfluenza viruses 1–3 and adenovirus species B. However, no benefit was seen in preventing respiratory syncytial virus. No severe adverse events were reported. Therefore, the rIFNα-2b nasal spray was effective and well tolerated for preventing common viral respiratory infections in the military recruits.

WITHDRAWN: Antivirals for the common cold

BACKGROUND

The common cold is a ubiquitous short and usually mild illness for which preventive and treatment interventions have been under development since the mid-40s. As our understanding of the disease has increased, more experimental antivirals have been developed. This review attempts to draw together experimental evidence of the effects of these compounds.

OBJECTIVES

To identify, assemble, evaluate and (if possible) synthesise the results of published and unpublished randomised controlled trials of the effects of antivirals to prevent or minimise the impact of the common cold.

SEARCH STRATEGY

We searched electronic databases, corresponded with researchers and handsearched the archives of the MRC's Common Cold Unit (CCU).

SELECTION CRITERIA

We included original reports of randomised and quasi-randomised trials assessing the effects of antivirals on volunteers artificially infected and in individuals exposed to colds in the community.

DATA COLLECTION AND ANALYSIS

We included 241 studies assessing the effects of Interferons, interferon-inducers and other antivirals on experimental and naturally occurring common colds, contained in 230 reports. We structured our comparisons by experimental or community setting.

MAIN RESULTS

Although intranasal interferons have high preventive efficacy against experimental colds (protective efficacy 46%, 37% to 54%) and to a lesser extent against natural colds (protective efficacy 24%, 21% to 27%) and are also significantly more effective than placebo in attenuating the course of experimental colds (WMD 15.90, 13.42 to 18.38), their safety profile makes compliance with their use difficult. For example, prolonged prevention of community colds with interferons causes blood-tinged nasal discharge (OR 4.52, 3.78 to 5.41). Dipyridamole (protective efficacy against natural colds 49%, 30% to 62%), ICI 130, 685 (protective efficacy against experimental colds 58%, 35% to 74% ), Impulsin (palmitate) (protective efficacy against natural colds 44%, CI 35% to 52% ) and Pleconaril (protective efficacy against experimental colds 71%, 15% to 90% ) appear to have important antiviral properties and are well-tolerated. The evidence of effectiveness of other compounds in the treatment of experimental or natural colds is sparse.

AUTHORS' CONCLUSIONS

There are no licensed effective antivirals for the common cold. Because prolonged intranasal administration causes a clinical picture which is not distinguishable from the common cold, interferons have no place in everyday use. Further assessment of the effects of dipyridamole, ICI 130, 685, Impulsin (palmitate) and Pleconaril in preventing the common cold should be carried out. Given the multi-agent nature of the causes of the common cold, future research efforts should focus on non virus-specific compounds.

Epidemiology, pathogenesis, and treatment of the common cold

OBJECTIVE

Reading this article will reinforce the reader's knowledge of the pathogenesis of the common cold. The rationale for current and potential therapies for the common cold are reviewed in the context of current concepts of the pathogenesis of these illnesses.

DATA SOURCES AND STUDY SELECTION

A MEDLINE literature search was done using the search terms common cold, rhinovirus, and viral respiratory infection. The search was restricted to the English language. Articles were selected for review if the title and/or abstract suggested the content was relevant to the subject of this review. The bibliographies of selected articles were used as a source of additional literature.

RESULTS

Recent studies suggest that the host response to the virus is an important contributor to the pathogenesis of the common cold. Inflammatory mediators, especially the pro-inflammatory cytokines, appear to be an important component of this response and present an attractive target for new interventions for common cold therapies. Currently available treatments for the common cold have limited efficacy against specific symptoms. These therapies should be selected to treat the specific symptoms that are perceived to be the most bothersome by the patient.

The use of interferon-alpha in virus infections

The interferons (IFN) act too slowly to arrest acute viral infections, but interferon-alpha (IFN alpha) preparations have proved useful in some chronic infections and will clearly be used increasingly in these in the future. In the preparations derived from human leucocytes or cultured B lymphoblastoid cells, which are in routine clinical use, mixtures of a number of distinct subtypes of human IFN alpha have been identified. There are also 3 slightly different versions of the same single subtype, IFN alpha-2, made by recombinant DNA procedures in bacteria. IFN alpha preparations are injected intramuscularly or subcutaneously. Dose-related side effects are common but usually tolerable, but prolonged treatment may cause increasing fatigue and depression. Some patients form neutralising antibodies which block the effects of the IFN; these appear to be relatively more common after recombinant IFN alpha-2 than after IFN derived from human cells. Given intranasally, IFN alpha can prevent a subsequent experimental rhinovirus infection, or the spread of natural colds within a family. Repeated administration progressively damages the nasal mucosa, so that long term prophylaxis is not possible. IFN alpha has proved useful in patients with papillomavirus warts of the larynx, ano-genital region (condyloma acuminata) and skin (common warts). Treatment regimens remain to be optimised and are likely to include surgery or other treatments. IFN alpha and zidovudine (azidothymidine) synergistically inhibit the growth of HIV in vitro, and combination are on trial in patients with early AIDS. Very large doses of IFN alpha are effective against Kaposi's sarcoma in some AIDS patients. In chronic hepatitis B, continuing virus replication may lead to cirrhosis or primary liver cancer. Earlier clinical trials with IFN alpha gave inconclusive results, but recent large studies have confirmed that 25 to 40% of patients obtain benefit; this probably results from both the antiviral and the immunomodulatory effects of IFN alpha. In patients with chronic hepatitis C, the biochemical markers usually improve rapidly during IFN alpha administration, but relapse if treatment is stopped after only a few months; to increase the chances of sustained cure, the treatment period is now being prolonged.

The efficacy of intranasal interferon alpha-2a in respiratory syncytial virus infection in volunteers

In a double-blind, placebo-controlled study, self-administered intranasal interferon alpha-2a or placebo was given both before and after challenge with respiratory syncytial virus. The incidence of colds and the severity of signs and symptoms were reduced in those receiving interferon alpha-2a as compared with those given placebo. In a further double-blind, placebo-controlled study, self-administered interferon alpha-2a or placebo was given only to those volunteers who developed colds following challenge with respiratory syncytial virus. There was no evidence that interferon alpha-2a reduced the severity of the signs and symptoms or shortened the duration of the illness. The similarity of these results to the effect of interferon alpha-2a in rhinovirus infections in volunteers is discussed.

Intranasal tolerance and histopathologic effects of a novel synthetic interferon, rIFN-alpha Con1

In a double-blind trial 119 adults were randomly assigned to receive daily sprays of placebo (N = 30) or rIFN-alpha Con1 3 MU (N = 29), 9 MU (N = 30), or 30 MU (N = 30) per day for 25 consecutive days. Fifty-nine subjects were removed from treatment because of abnormal nasal exams (N = 56) or irritative symptoms (N = 3). The fraction of drop-outs in the placebo group (30%) was significantly different (P less than 0.05) from that in the 3 MU (55%), 9 MU (57%), or 30 MU (67%) groups. Nasal mucosal biopsies collected 1-2 days after completing spray use detected moderate or marked lymphocytic infiltration in 10% of placebo (N = 10), 90% of 3 MU (N = 9), 85% of 9 MU (N = 13), and 70% of 30 MU (N = 10) subjects (P less than 0.05, placebo vs each rIFN-alpha Con1 group). All 3 dose levels of rIFN-alpha Con1 were associated with significant clinical and histopathologic signs of nasal irritation. The findings suggest that intranasal rIFN-alpha Con1 does not have a more favorable therapeutic index than rIFN-alpha 2 and that the risk of nasal irritation relates more closely to the anti-viral activity than the protein content of the rIFN-alpha administered.

Failure to demonstrate synergy between interferon-alpha and a synthetic antiviral, enviroxime, in rhinovirus infections in volunteers

Marked synergy between the antirhinoviral effect of rHuIFN alpha and enviroxime has been observed in vitro but an attempt to demonstrate it in volunteers was unsuccessful. The sub-optimal intranasal dose of rHuIFN alpha (0.18 Mu four times daily for 4 1/4 days) used prophylactically in the trial did reduce the severity of colds induced by RV9 and 14, but the difference did not reach statistical significance and was not enhanced by the administration of enviroxime (0.28 mg six times daily for six days). The main reason for failure is thought to be the rapid removal of enviroxime from the nose when given intranasally.

Recombinant human interferon-gamma as prophylaxis against rhinovirus colds in volunteers

The first evaluation of intranasal (i.n.) recombinant human interferon-gamma (rHuIFN-gamma) as prophylaxis against experimental rhinovirus (RV) infection and illness in volunteers is reported. In two studies, 7 of 27 (26%) of the volunteers who received rHuIFN-gamma (2 Mu i.n. 3 x /day) had either blood stained nasal secretions or nose bleeding which was not observed in any of the 26 placebo recipients. Some volunteers given rHuIFN-gamma showed increased nasal secretion and the majority complained of slight nasal stuffiness, whereas only a few of those receiving placebo complained of these symptoms. In the prophylactic study, 17 volunteers were given the above regimen of rHuIFN-gamma and 17 placebo; after the fourth dose all were challenged with RV9, followed 1 h later with RV14 (100 TCID50 of each virus). Compared with the placebo-treated controls, interferon recipients showed no significant reduction in the proportion who developed colds or became infected, and there was an increase in both their mean clinical scores and mean nasal secretion weights. Thus i.n. rHuIFN-gamma did not prevent rhinovirus infection or illness and may enhance the symptoms.

Tolerance and nasal histopathologic effects of long-term, low-dose intranasal recombinant interferon alpha-2A (Roferon-A)

The dose-related tolerance and histopathologic effects of intranasal recombinant interferon alpha-2a (rIFN-alpha 2a) were determined in a blind study in which healthy subjects were randomized to receive sprays of interferon (IFN) (3 or 6 MU/day) or placebo for 28 days. Adverse nasal symptoms (bleeding, obstruction, irritation) tended to occur more often in the IFN 6 MU/day group. Blind analysis of biopsy samples collected before and after IFN treatment revealed that both IFN groups had significant histologic changes, most commonly an increased degree of lymphocytic infiltration in the subepithelium and underlying glandular zones. Changes developed in 61% of 18 recipients of IFN 6 MU/day, 37% of 19 recipients of IFN 3 MU/day, and 6% of 18 placebo recipients. Serum antibodies to rIFN-alpha 2a detectable by EIA were found in 4 recipients of IFN 3 MU/day and 2 recipients of IFN 6 MU/day, one-third of whom were positive by neutralization bioassay. The findings would predict that these rIFN-alpha 2a dosages would be associated with an excess of adverse side effects during long-term use in healthy adults.