Effectiveness of nirmatrelvir/ritonavir in hospitalized haematological malignancy patients with mild-to-moderate COVID-19: A retrospective study

Patients with haematological malignancies (HMs) are highly vulnerable to COVID-19 due to their immunocompromised status, which leads to prolonged viral clearance and severe outcomes. Nirmatrelvir/ritonavir has shown efficacy in reducing severity and mortality in high-risk COVID-19 outpatients, but its effectiveness in hospitalized HM patients remains unclear. We conducted a retrospective study to assess the effectiveness of nirmatrelvir/ritonavir on mortality and viral clearance in hospitalized HM patients with mild-to-moderate COVID-19 during China's first COVID-19 surge. Mortality rate and viral clearance time were the primary end-points. Cox proportional hazards models were used to detect factors associated with mortality and viral clearance. A total of 116 HM patients, with a median age of 47.2 years, hospitalized for a minimum of 5 days with mild-to-moderate COVID-19, were included in this study. There was no difference in the 90-day mortality rate between HM patients treated with nirmatrelvir/ritonavir within 5 days and those not treated (4.9% vs. 5.3%, p = 1.000). Nirmatrelvir/ritonavir use within 5 days reduced the time to viral clearance (hazard ratio [HR] = 1.59, 95% confidence interval [CI] 1.04–2.42). Nirmatrelvir/ritonavir use within 5 days in hospitalized HM patients with mild-to-moderate COVID-19 does not reduce mortality but accelerates viral clearance.