LAUSR

Cidofovir (CDV) is a nucleotide analogue with broad antiviral activity and has been approved for the treatment of cytomegalovirus (CMV) retinitis in patients with acquired immunodeficiency syndrome. Data on the use of CDV for anti-CMV treatment in the patients with haploidentical hematopoietic stem cell transplantation (haplo-HSCT) is rare. In this study, 31 (defined as CDV-second line treatment, ST group) out of 101 (conventional treatment, CT group) haplo-HSCT recipients with CMV infection being front-line treated with intravenous ganciclovir (GCV) or foscarnet (FSC) between the year 2017 and 2019, failed or intolerated to the preemptive antiviral therapy, and were switched to CDV therapy. Also, another 9 (CDV-front line treatment, FT group) patients with CMV infection were preemptively treated with CDV. CDV was used at a dose of 5 mg/kg per week until CMV-DNA negative twice with quantification polymerase chain reaction (qPCR) detection or disease progression. 23/28(82.1%) patients achieved treatment response with a median response time of 9(2-23) days and 20/28(71.8%) obtained complete response (CR) in CDV-ST group. While 6/8(75.0%) acquired CR with a median time of 6 (4-25) days in CDV-FT group. Higher response rate was seen in CDV treatment groups, though not significantly different, when being compared with those in CT groups (66/95(69.5%), 7 (2-34) days, 65(68.4%, respectively, all P-value >0.05). Also, there was not statistical difference in CMV-related mortality among the three groups (P-value >0.05). With a median follow-up of 10 (1-28) months, cumulatively 8/22(36.3%) patients experienced CMV reactivation in CDV-ST group, while 23/62(37.0%) happened in CT group, there was not significant difference (P>0.05). Whereas none with CMV recurrence was observed in the CDV-FT group. CDV-related toxicities were recorded in a total of 13/40 (32.5%) patients, shown as 7(17.5%) with I~II° gastrointestinal side effects, 6(15%) presenting reversible nephrotoxicity. Taking together, salvage treatment with CDV shows no worse efficacy than ganciclovir or foscarnet does in the front line treatment of CMV infection in haplo-HSCT recipients. Also, CDV-related toxicity is tolerated. Keywords: cidofovir, CMV infection, haplo-hematopoietic stem cell transplantation, efficacy, safety No relevant conflicts of interest to declare.