At present, there are no antiviral drugs registered for use in patients with COVID-19. Supportive care [10,11,12] is standard of care, and the currently available drugs are as follows:
Protease inhibitors (lopinavir/ritonavir; darunavir + ritonavir; darunavir/cobicistat) [10], already used for the chronic treatment of HIV infection and promising treatment option for COVID-19 infections, based on the proven efficacy against SARS-CoV (in combination with ribavirin) [13]. Clinical evidence however remains limited. The effectiveness of lopinavir/ritonavir is suggested by anecdotal cases [14]. In a similar way, anecdotal cases suggest how this administration is able to reduce the viral load of COVID-19 very quickly [15]. Three randomized, open-label clinical trials are currently listed on https://clinicaltrials.gov/ evaluating darunavir/cobicistat as a potential therapeutic option for COVID-19.
Chloroquine or hydroxychloroquine, drugs used in malaria, amebiasis, and in some diseases with autoimmune pathogenesis; clinical studies have shown the activity in vitro and in the animal model of chloroquine phosphate as an antiviral against the SARS virus [16, 17] and avian influenza [18]. Despite the lack of clear evidence of benefit, hydroxychloroquine is recommended off label for the treatment of COVID-19 by the Chinese National guidelines [19, 20], and the US Food and Drug Administration has issued an Emergency Use Authorization for the treatment of adult patient with COVID-19. By contrast, the IDSA (Infectious Disease Society of America) recently concluded that because of insufficient data, they could not recommend any particular treatment for patients with COVID-19 [21].
Azithromycin, an antibiotic belonging to the macrolide family [22].
Tocilizumab, monoclonal antibody, already used in the treatment of severe syndromes caused by release of cytokines induced by CAR-T lymphocytes (chimeric antigen receptor T cell) [23].
Remdesivir (GS-5734) is a broad-spectrum antiviral nucleotide with potent in vitro activity against a range of RNA viruses including Ebola virus, Marburg, MERS-CoV, SARS-CoV, respiratory syncytial virus, Nipah virus, and Hendra virus [24,25,26]. The mechanism of action of remdesivir is premature termination of viral RNA transcription.
Methylprednisolone 20 mg × 2/day, according to clinical/radiological judgment and the presence of any of these conditions:
Hypoxia at rest in ambient air (SpO2 < 93%, pO2 < 70 mmHg)
Respiratory rate > 30 acts/min in ambient air
P/F ratio ≤ 300 mmHg
CT scan with severe, extensive, bilateral interstitial involvement with fibrotic evolution
Sodic Enoxaparin [27]:
Low-intensity care COVID-19 wards: 100 U/Kg/day; 70 U/Kg × 2/day for obese patient (BMI > 30) or at particularly high thrombotic risk (e.g., neoplasms, previous DVT)
Intermediate/high-intensity care COVID-19 departments: 70 U/Kg × 2/day
Antibiotic therapy: we suggest to use only in cases in which a superinfection cannot be excluded. For community-acquired forms of bacterial pneumonia (CAP), a third-generation cephalosporin, clarithromycin, or azithromycin or alternatively fluoroquinolones can be inserted, with attention to these last two due to the effect of elongation on QT.
In a low/intermediate care setting, such as the one in which we are working and to which this review is directed, we propose two possible therapeutic schemes, extrapolated from clinical experience and scientific evidence currently available but nevertheless continuously evolving, accelerated by the ongoing emergency. The schemes suggested are:
Scheme A Hydroxychloroquine 200 mg × 2/day or 3/day (or chloroquine 500 mg × 2 day) [20] + lopinavir/ritonavir 200/50 mg × 2/day (or darunavir/cobicistat 800 /150 mg day or darunavir 800 mg day + ritonavir 100 mg day)
Scheme B Hydroxychloroquine 200 mg × 2/day or 3/day (or chloroquine 500 mg × 2 day) [20] + azithromycin 500 mg day.
In Scheme A, in our unit, we prefer the use of darunavir + ritonavir or darunavir/cobicistat, although with less scientific evidence than lopinavir/ritonavir, because of its greater tolerability.
Scheme B seems to be supported by the recent publication of Gautret et al. that shows how hydroxychloroquine treatment is significantly associated with viral load reduction/disappearance in COVID-19 patients, effect reinforced by azithromycin [22]. However, the latest NIH COVID-19 guidelines panel and IDSA guideline panel recommend against this combination, except in the context of a clinical trial, for adverse effects, especially prolonged QTc interval [28, 21].
We consider the addition of heparin to these schemes if no contraindications are present.
Therapy should be continued for 7–20 days with timing to be established according to clinical evolution.
All these drugs have to be seriously evaluated for interactions with other therapy (in particular using lopinavir/ritonavir) and for the adverse events:
Hydroxychloroquine and chloroquine can lengthen the QTc for which they need periodic ECG assessment and can lead to lesions of the retina and to glycidic intolerance.
Azithromycin can also lengthen the QTc, which requires periodic ECG assessment.
Lopinavir/ritonavir can cause diarrhea, nausea, vomiting, and increased amylase and lipase.
Darunavir/cobicistat may give rise to creatinine, amylase, and lipase.
Darunavir + ritonavir can increase amylase and lipase.
For the management of these drugs in relation to adverse effects on QTc interval, we refer to SIC guidelines (https://www.sicardiologia.it/public/SIC-Covid-e-QT.pdf), while for the possible interactions with other drugs, we consult http://www.covid19-druginteractions.org/.
Up to 20% of mild/moderate infections can develop into ARDS [2]. If rapid clinical deterioration during standard therapy occurs and oxygen therapy is needed, remdesivir can be used for compassionate use [29]. As soon as available, suspend Scheme A or B and continue with remdesivir 200 mg on day 1 then 100 mg/day for another 9 days in combination with chloroquine 500 mg, 1 × 2/day or hydroxychloroquine 200 mg, 1 × 2/day. If the patient develops a BCRSS score 3 or MEWS ≥ 3, evaluate dexamethasone and/or tocilizumab.
Tocilizumab should be administrated in apiretic patient > 72 h and/or at least 7 days after the onset of symptoms, if there is a worsening of gas exchange (BCRSS score ≥ 3) and if there are high levels of IL6 (or D-dimer and/or RCP and/or ferritin and/or fibrinogen increasing progressively). Patients aged < 18 years or with one or more of these conditions, transaminases greater than 5 times the norm, neutrophil value < 500 cell/mmc, PLT < 50,000 cells/mmc, sepsis, comorbidities related to an unfavorable outcome, diverticulitis or intestinal perforation, ongoing skin infection, and immunosuppressive antirejection therapy, should be excluded for tocilizumab therapy.
The therapeutic scheme recommended is for a maximum of 3 infusions at a dosage of 8 mg/kg body weight (maximum dosage per infusion 800 mg) with the second infusion done 8–12 h after the first. If clinical response is partial or incomplete, a third infusion 16–24 h after the first infusion is possible. After 24 h from the last administration, repeat the plasma dosage of IL-6 and/or D-dimer. Treatment must be accompanied by antiviral treatment (lopinavir/ritonavir or remdesivir + chloroquine/hydroxychloroquine) and/or steroid (dexamethasone) [30].