Early experience with modified dose nirmatrelvir/ritonavir in dialysis patients with coronavirus disease-2019

IntroductionNirmatrelvir/Ritonavir was approved for use in high risk outpatients with coronavirus disease (COVID-19). However, patients with severe chronic kidney disease, including patients on dialysis, were excluded from the phase 3 trial, and currently the drug is not recommended below a glomerular filtration rate of 30 ml/min/1.73m2. Based on available pharmacological data and principles, we developed a modified dose which was lower, and administered at longer intervals.We administered nirmatrelvir/ritonavir as 300/100 mg on day one, followed by 150/100 mg daily from day two to day five. In this case series, we report the initial experience with this modified dose regimen. MethodsThis is a retrospective chart review, conducted after obtaining institutional board approval. Demographic and outcome data was abstracted from the electronic medical record for dialysis patients who developed COVID-19 during the period of study and received nirmatrelvir/ritonavir. The principal outcomes we describe are symptom resolution, and safety data with the modified dose regimen in the dialysis patients. Results19 patients developed COVID-19 during the period of study of whom 15 received nirmatrelvir/ritonavir. 47% of them were female and 67% had diabetes. Most patients had received three doses of the vaccine (80%) while 13% were unvaccinated. Potential drug interactions concerns were common (median 2 drugs per patient) with amlodipine and atorvastatin being the commonest drugs requiring dose modification. Nirmatrelvir/ritonavir use was associated with symptom resolution in all patients, and was well tolerated. One patient had a rebound of symptoms, which improved in 2 more days. There were no COVID-19 related hospitalizations or deaths in any of the patients. ConclusionIn this case series of 15 hemodialysis patients with COVID-19, a modified dose of nirmatrelvir/ritonavir use, with pharmacist support for drug interaction management, was associated with symptom resolution, and was well tolerated with no serious adverse effects.