Proxalutamide for the treatment of COVID-19 rebound following Paxlovid treatment: Report of four cases and review of the literature

Background: The pandemic the coronavirus disease 2019 (COVID-19) has created a global health crisis. Although Paxlovid is recommended for the early-stage treatment of mild-to-moderate COVID-19 in patients at increased risk of progression to severe COVID-19, more and more cases are reported a COVID-19 rebound after Paxlovid treatment. Currently, information on the additional treatment for COVID-19 rebound following Paxlovid treatment is limited. Case Report: Here, we present four cases with COVID-19 who were mild on admission. All cases experienced a COVID-19 rebound and progressed to severe COVID-19, following treatment with Paxlovid (300 mg of nirmatrelvir with 100 mg ritonavir, twice daily for 5 days). After being treated with proxalutamide (300 mg/day), all cases finally turned real-time reverse transcription polymerase chain reaction (RT-PCR) negative. Conclusion: Our cases suggested that proxalutamide might be an effective remedial treatment option for patients experiencing a COVID-19 rebound after Paxlovid treatment.