Background Pneumocystis carinii pneumonia (PCP) is an uncommon severe complication in immunocompromised patients. There is only one marketed treatment to prevent PCP: trimethoprime-sulfamethoxazole (TMP-SMZ). Due to side-effects (mainly neutropaenia), TMP-SMZ is sometimes replaced by off-label drugs. Notably, atovaquone has been studied in several conditions, but its effectiveness has never been assessed in lung transplantation.

Purpose Our study intended to compare the effectiveness of TMP-SMZ and atovaquone for preventing PCP in lung-transplant recipients.

Material and methods This single-centre, retrospective study included deceased and living patients, who received a lung transplant from 1 January 2007 to 31 August 2016, and PCP prophylaxis for more than 1 year. Inclusion in the groups was based on treatment at the time of PCP or death or, failing that, on 31 August 2017. Initially all patients were treated with TMP-SMZ (daily dosage regarding renal function and toxoplasmosis status). This treatment could be continued (group 1) or, if side-effects appeared, switched to atovaquone 750 mg or 1,500 mg daily (group 2 and 3, respectively, according to the prescriber’s choice). The reasons for prescribing atovaquone were assessed.

Results Two hundred and ten patients were included in the study. Death rate was 23% in group 1 (n=160), 37% in group 2 (n=41) and 20% in group 3 (n=9), but group 2 patients were transplanted in an earlier period than group 3 (2007 to 2014 vs 2013 to 2016). No patient directly died from PCP. Before switching to atovaquone, patients were treated with TMP-SMZ for 0.5 years (0.0; 4.2) (group 2) and 0.4 years (0.1; 1.4) (group 3). The main reason for stopping TMP-SMZ was haematological toxicity (63% of cases). Only 1 patient (group 2), taking the treatment once a week developed PCP.

Conclusion This is the first study evaluating atovaquone’s effectiveness in lung-transplant recipients. It seems to be effective, considering that the unique case of PCP was due to poor compliance. These retrospective results have to be confirmed. Because of it high cost and gastrointestinal effects that may affect treatment adhesion, atovaquone should be saved only for patients with TMP-SMZ intolerance.

No conflict of interest