Molnupiravir & Nirmatrelvir/Ritonavir in the Treatment of Systemic Autoimmune Rheumatic Diseases

July 7, 2023

Molnupiravir (MP) and Nirmatrelvir/ritonavir (NM/R) were the first two orally administered antiviral drugs authorized to treat COVID-19. However, the last two phases of clinical trials testing MP and NM/R in COVID-19 were conducted in unvaccinated individuals and before the emergence of the Omicron variant. Additionally, clinical trials didn’t include people suffering from systemic autoimmune rheumatic diseases (SARDs).

To assess the effectiveness and safety of MP and NM/R treatment in SARD patients, researchers analyzed data from 74 (mostly vaccinated) patients with SARDs (findings were published in December 2022). Patients were infected with SARS-CoV-2 between February and August 2022 and were treated with MP or NM/R. SARD patients included in the study were most commonly treated with corticosteroids, mycophenolate, TNF inhibitors, methotrexate, and rituximab. 

Four patients who received NM/R experienced adverse effects: metallic taste, gastrointestinal upset, and hypertension. The majority of treated patients recovered at home without complications. However, two patients experienced COVID-19 “rebound” and experienced severe COVID-19. Upon follow-up, patients’ symptoms resolved. The authors mention that COVID-19 rebound after NM/R  treatment was observed previously and is reported on in earlier studies. 

Researchers state that the data suggests these two antiviral drugs present acceptable safety profiles among the population of vaccinated high-risk SARD patients infected with the Omicron variant and have been used with positive outcomes. However, it is necessary to monitor patients for cases of COVID-19 rebound. This will allow for gaining better insight into real-world data regarding the efficacy and safety of  MP and NM/R in the SARD population.