S-217622, a SARS-CoV-2 main protease inhibitor, decreases viral load and ameliorates COVID-19 severity in hamsters.

In parallel with vaccination, oral antiviral agents are highly anticipated to act as countermeasures for the treatment of the coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Oral antiviral medication demands not only high antiviral activity, but also target specificity, favorable oral bioavailability, and high metabolic stability. Although a large number of compounds have been identified as potential inhibitors of SARS-CoV-2 infection in vitro, few have proven to be effective in vivo. Here, we show that oral administration of S-217622 (ensitrelvir), an inhibitor of SARS-CoV-2 main protease (Mpro, also known as 3C-like protease), decreases viral load and ameliorates disease severity in SARS-CoV-2-infected hamsters. S-217622 inhibited viral proliferation at low nanomolar to sub-micromolar concentrations in cells. Oral administration of S-217622 demonstrated favorable pharmacokinetic properties and accelerated recovery from acute SARS-CoV-2 infection in hamster recipients. Moreover, S-217622 exerted antiviral activity against SARS-CoV-2 variants of concern (VOCs), including the highly pathogenic Delta variant and the recently emerged Omicron BA.5 and BA.2.75 variants. Overall, our study provides evidence that S-217622, an antiviral agent that is under evaluation in a phase 3 clinical trial (clinical trial registration no. jRCT2031210350), possesses remarkable antiviral potency and efficacy against SARS-CoV-2 and is a prospective oral therapeutic option for COVID-19.

Successful deceased donor kidney transplantation to a recipient with a history of COVID-19 treatment.

CASE PRESENTATION: A 49-year-old Asian male, who had undergone hemodialysis for >16 years, complained of a fever, dysgeusia and dysosmia, and was diagnosed with COVID-19 pneumonia based on severe acute respiratory syndrome coronavirus 2 polymerase chain reaction (SARS-CoV-2 PCR) and computed tomography (CT). Treatment was started with oral favipiravir and ciclesonide inhalation. On the 10th day of treatment, the patient had a persistent high fever and a chest CT showed exacerbation of pneumonia, so dexamethasone was intravenously started. He was discharged after confirming two consecutive negative SARS-CoV-2 PCR tests. Three months after COVID-19 treatment, a SARS-CoV-2 PCR test was negative and he underwent a deceased donor kidney transplantation. Basiliximab induction with triple drug immunosuppression consisting of extended-release tacrolimus, mycophenolate mofetil and prednisolone, which is our regular immunosuppression protocol, was used. He was discharged on postoperative day 18 without the need for postoperative hemodialysis or any complications. The serum creatinine level was 1.72 mg/dL 95 days postoperatively and he had a favorable clinical course that was similar to deceased donor kidney recipients without a history of SARS-CoV-2 infection. CONCLUSION: We report the first case of a kidney transplantation after COVID-19 treatment in Japan and the fourth case globally. We would like to provide information about our successful case due to the anticipated increase in similar candidates in the near future.