Antimicrobial prophylaxis in patients with immune thrombocytopenia treated with rituximab: a retrospective multicenter analysis.

The primary aim of this study was to describe the use of primary anti-infective prophylaxis (AP) in common clinical practice in patients affected by immune thrombocytopenia (ITP) and treated with RTX. Population studied consisted of patients affected by ITP (age ≥ 18 years) who had received at least one dose of RTX from January 2008 to June 2018. Five Italian haematology centres participated in the current study. Data were retrospectively collected: demographic data (age, gender), concomitant comorbidities and previous therapies for ITP, characteristics of AP, the occurrence of infections and their management. The ITP cohort consisted of 67 patients sub-grouped into two categories according to the administration of AP: (1) treated with AP (N= 34; 51%) and (2) not treated with AP (N=33, 49%). AP consisted of combined trimethoprim/sulfamethoxazole (TMP/SMX) and acyclovir (AC) in half of patients. TPM/SMX as a single agent was adopted in 32% patients and one patient received only AC. Overall, infections were experienced in 15% of patients during follow-up with a similar proportion in the 2 groups (treated and not treated) of patients (14.7% vs 15%). Clinical course of infections was however, less severe in patients treated with AP, where all infections were grade 2 and did not require hospitalization. In neither group of patients was reported Pneumocystis pneumonia. In conclusion, despite the absence of clear evidence, our analysis shows that AP in patients with ITP receiving RTX is frequently adopted, even if in the absence of well-defined criteria. Prophylaxis administration is quite consistent within the same haematological Center; thus, it seems related to clinicians' experience.