Plasma and intracellular ribavirin concentrations are not significantly altered by abacavir in hepatitis C virus-infected patients

The triple combination of Remdesivir (GS-441524), Molnupiravir and Ribavirin is highly efficient in inhibiting coronavirus replication in human nasal airway epithelial cell cultures and in a hamster infection model

The use of fixed dose-combinations of antivirals with different mechanisms of action has proven a key in the successful treatment of infections with HIV and HCV. For the treatment of infections with SARS-CoV-2 and possible future epi-/pandemic coronaviruses, it will be important to explore the efficacy of combinations of different drugs, in particular to avoid resistance development, such as in patients with immunodeficiencies. As a first effort, we studied the antiviral potency of combinations of antivirals. To that end, we made use of primary human airway epithelial cell (HAEC) cultures grown at the air-liquid interface that were infected with the beta coronavirus OC43. We found that the triple combination of GS-441524 (parent nucleoside of remdesivir), molnupiravir, and ribavirin resulted in a more pronounced antiviral efficacy than what could be expected from a purely additive antiviral effect. The potency of this triple combination was next tested in SARS-CoV-2 infected hamsters. To that end, for each of the drugs, intentionally suboptimal or even ineffective doses were selected. Yet, in the lungs of all hamsters that received triple prophylactic therapy with suboptimal/inactive doses of GS-441524, molnupiravir, and ribavirin, no infectious virus was detectable. Our finding indicate that co-administration of approved drugs for the treatment of coronavirus infections should be further explored but also against other families of viruses with epidemic and pandemic potential for which no effective antiviral treatment is available.

Pharmacokinetics/Pharmacodynamics of Antiviral Agents Used to Treat SARS-CoV-2 and Their Potential Interaction with Drugs and Other Supportive Measures: A Comprehensive Review by the PK/PD of Anti-Infectives Study Group of the European Society of Antimicrobial Agents

There is an urgent need to identify optimal antiviral therapies for COVID-19 caused by SARS-CoV-2. We have conducted a rapid and comprehensive review of relevant pharmacological evidence, focusing on (1) the pharmacokinetics (PK) of potential antiviral therapies; (2) coronavirus-specific pharmacodynamics (PD); (3) PK and PD interactions between proposed combination therapies; (4) pharmacology of major supportive therapies; and (5) anticipated drug-drug interactions (DDIs). We found promising in vitro evidence for remdesivir, (hydroxy)chloroquine and favipiravir against SARS-CoV-2; potential clinical benefit in SARS-CoV-2 with remdesivir, the combination of lopinavir/ritonavir (LPV/r) plus ribavirin; and strong evidence for LPV/r plus ribavirin against Middle East Respiratory Syndrome (MERS) for post-exposure prophylaxis in healthcare workers. Despite these emerging data, robust controlled clinical trials assessing patient-centred outcomes remain imperative and clinical data have already reduced expectations with regard to some drugs. Any therapy should be used with caution in the light of potential drug interactions and the uncertainty of optimal doses for treating mild versus serious infections.

Ribavirin and cellular ribavirin-triphosphate concentrations in blood and bronchoalveolar lavage fluid in two lung transplant patients with respiratory syncytial virus

Respiratory syncytial virus (RSV) is responsible for significant morbidity and mortality in the lung transplant population. Oral and aerosolized ribavirin may improve outcomes in lung transplant patients with RSV; however, data relating ribavirin concentrations in plasma and intracellular ribavirin triphosphate (iRTP) concentrations in blood and bronchoalveolar lavage (BAL) fluid cells with efficacy and safety are lacking. We describe ribavirin and iRTP concentrations within various compartments in two adult lung transplant recipients with RSV who were sampled throughout successful treatment courses with oral and inhaled ribavirin. In patient 1, iRTP BAL concentrations decreased by 45% over 3 days after changing inhaled ribavirin to oral (6.32 to 3.43 pmol/10⁶ cells). In patient 2, iRTP BAL concentrations were 103 pmol/10⁶ cells after 5 days of oral followed by 5 days of inhaled ribavirin. Further study is needed to describe ribavirin pharmacokinetics in the respiratory compartment to inform clinical use of ribavirin for respiratory viruses.