Nirmatrelvir/ritonavir for the treatment of immunocompromised adult patients with early-stage symptomatic COVID-19: A real-life experience.

Regardless of vaccination status, progression to severe coronavirus disease 2019 (COVID-19) is still a relevant cause of morbidity among immunocompromised patients. Despite the proven efficacy of nirmatrelvir/ritonavir (NMV/r), concerns remain regarding the potential for drug-to-drug interactions (DDIs) and the safety in this at-risk population. We aimed to evaluate the clinical outcomes of immunocompromised patients treated with NMV/r, as well as the occurrence of DDIs and treatment-emergent adverse events (TEAEs). This retrospective observational study included all the patients with some form of immunosuppression and laboratory-confirmed COVID-19 that received NMV/r at our center from April to August 2022. The main outcome was worsening of the clinical status (increase of ≥1 point from baseline in a validated clinical progression scale) by Days +7 and +28 after the initiation of therapy. Safety outcomes included the rates of any TEAE and potentially severe DDIs. We included 110 patients. Main causes of immunosuppression were hematological malignancy (58.2%) (mainly multiple myeloma [22.7%] and non-Hodgkin lymphoma [13.6%]), active chemotherapy (30.0%) and hematopoietic stem cell transplantation (14.5%). Clinical worsening by Days +7 and +28 was observed in four (3.6%) and five patients (4.5%), respectively. Only one patient had a positive SARS-CoV-2 polymerase chain reaction test at Day +28. At least one potentially severe DDI was observed in 56.4% of the patients. The rate of attributable TEAEs was 10.9%, although only two patients (1.8%) required premature discontinuation of NMV/r. Early initiation of NMV/r therapy should be considered in immunocompromised patients with COVID-19, with particular attention to interacting medications.