Interferons in COVID-19: missed opportunities to prove efficacy in clinical phase III trials?

Interferons were repeatedly used in the therapy of COVID-19 due to their antiviral effects. Three recently published randomized controlled clinical phase III trials (WHO SOLIDARITY, ACTT-3, and SPRINTER) missed their primary objectives, i.e., a significant therapeutic effect of interferons was not demonstrated in these studies. In only one randomized controlled phase III trial (TOGETHER), a significant reduction in the hospitalization rate was revealed. Our study analyzes these findings, gives possible explanations for the failure of interferons, provides a proposal on how these agents could be successfully used, and also highlights the limitations of their employment in COVID-19. Interferons are apparently beneficial only if the patients are in the early stage of this disease and when they are usually not hospitalized, i.e., if the patients do not require oxygen support and/or if corticosteroids are not yet indicated. Furthermore, a higher dosage than the one used in the long-term treatment of multiple sclerosis with interferon beta or of chronic viral hepatitis with interferon alpha or lambda should be employed to achieve a better therapeutic effect in COVID-19.

Interferons in the Therapy of Severe Coronavirus Infections: A Critical Analysis and Recollection of a Forgotten Therapeutic Regimen with Interferon Beta.

The pharmacological and immunological properties of interferons, especially those of interferon beta, and the corresponding treatment strategies are described, and the results of studies with different interferons in coronavirus infections are analysed. Furthermore, the data obtained with high-dosed native interferon beta in life-threatening acute viral diseases as well as the results of clinical pilot studies with high-dosed recombinant interferon beta-1a are provided because they serve as the rationale for the proposed therapeutic regimen to be applied in acute viral infections. This regimen differs from those approved for treatment of multiple sclerosis and consists of interferon beta-1a administered as a 24 hour intravenous infusion at a daily dose of up to 90 µg for 3-5 consecutive days. Since under this regimen transient severe side effects can occur, it is analysed which patients are suitable for this kind of treatment in general and if patients with severe coronavirus infections could also be treated accordingly.

Long-term survival benefit after adjuvant treatment of cutaneous melanoma with dacarbazine and low dose natural interferon alpha: A controlled, randomised multicentre trial.

In a prospective, controlled, randomised, multicentre study 252 patients with totally resected cutaneous melanoma (248 in stage II-III and 4 in stage IV) were either treated with two doses of dacarbazine (DTIC) followed by a 6-month treatment with 3 MU thrice weekly of highly purified natural interferon-alpha (n = 128; arm A) or received no adjuvant treatment (n = 124; arm B). Treatment was well tolerated. After a median follow-up of 8.5 years ITT analysis showed that the difference in survival was statistically significant with respect to melanoma-related deaths (HR = 0.65, CI = 0.46-0.97, p = 0.022) and close to significance with respect to overall survival (HR 0.71, CI 0.49-1.00, p = 0.052). The risk reduction of melanoma-associated death, calculated by Cox proportional hazards modelling, after adjusting for identified predictive variables, was almost 50% (p = 0.002). The overall efficacy of the treatment appeared to be mainly attributable to effects observed in patients with deep and/or metastasizing tumours (HR 0.60, CI 0.40-0.90, p = 0.013).

Successful application of highly purified natural interferon alpha (multiferon) in a chronic hepatitis C patient resistant to preceding treatment approaches.

A currently 65-year-old patient with histologically proven chronic hepatitis C and chronic hepatitis B (seroconversion in 1990) and additional compensated cirrhosis of the liver (Child A) achieved sustained complete biochemical and viral response following 5 and 14 months respectively of therapy with highly purified natural leukocyte interferon-alpha (3 x 3 MU weekly, nIFN-alpha, Multiferon). Prior to this treatment, various other therapy approaches including recombinant interferon-alpha2b (rIFN-alpha2b) or a combination of natural interferon-beta (nIFN-beta) and interferon-gamma (rIFN-gamma) had been carried out. Unfortunately, these had been unsuccessful. After a total treatment period of 76 months with nIFN-alpha and a subsequent follow-up period of 30 months, no relapse of chronic hepatitis C occurred. The patient's tolerance of the treatment was excellent and no substantial drug-related adverse events were observed. nIFN-alpha, which - unlike the recombinant IFN-alpha2 preparations - is a mixture of various physiologically expressed IFN-alpha subtypes, could possibly be an alternative in the treatment of difficult-to-treat patients with chronic hepatitis C.

Successful long-term application of highly purified natural interferon-alpha (multiferon) after preceding interferon approaches in a chronic hepatitis C patient with thrombocytopenia.

Treatment approaches with recombinant IFN-alpha2b and natural IFN-beta in a patient with chronic hepatitis C (genotype 1b) and cirrhosis had, in both cases, to be terminated prematurely due to breakthrough phenomena and thrombo-leukocytopenia up to WHO grade 3. After the patient was switched to highly purified natural IFN-alpha (Multiferon) the thrombocyte and leukocyte counts increased significantly, and sustained complete biochemical and virological response could be achieved.