Retrospective Review of Intravenous Pentamidine for Pneumocystis Pneumonia Prophylaxis in Patients Undergoing Hematopoietic Stem Cell Transplantation

Background: Patients undergoing allogeneic hematopoietic stem cell transplantation (HSCT) are at risk for infection from numerous opportunistic infections.  Pneumocystis jiroveci pneumonia (PJP) is a potentially life-threatening infection, which can manifest in immunocompromised individuals. The risk of PJP after allogeneic hematopoietic stem cell transplantation (HCT) is approximately five to 15 percent in the absence of prophylaxis. Current prophylaxis for PJP can include trimethoprim-sulfamethoxazole (TMP-SMX), dapsone, atovaquone and inhaled pentamadine (PEN), often with varying breakthrough rates. Issues with nebulized pentamidine treatment may include poor adherence to the regimen, coordination with medication administration and reimbursement. The use of intravenous (IV) PEN for PJP prophylaxis has been associated with minimal breakthrough rates in pediatric patients. However, no large studies have hitherto evaluated the efficacy of IV PEN for PJP prophylaxis in adult allogeneic HSCT patients.

Methods:  We performed a single-institution retrospective review of electronic medical records of patients who underwent allogeneic HSCT between 1 January 2001 and 1 May 2013, and who had received at least one dose of IV PEN. Data collected included patient demographics, diagnosis, previous chemotherapy, pre-transplant conditioning regimen, other medications, microbiology test results, and clinical outcomes.

Results: One hundred thirteen (113) patients who underwent 124 allogeneic HSCTs were included in the study. The median number of PEN doses administered per patient was 3 (range, 1-23).  Seventy-four of the patients (65%) received IV PEN as primary PJP prophylaxis; thirty-nine (35%) had IV PEN as second-line prophylaxis post-transplant, most switching from oral TMP-SMX because of intolerance to that medication. Side effects of IV PEN administration were minimal; one patient had transient shortness of breath after infusion.  No patients who had received IV pentamidine developed PJP infection.  No cases of PJP were observed in the 124 allogeneic HSCT recipients who received PJP prophylaxis with agents other than IV PEN.

Conclusion: This retrospective study showed that IV PEN is effective in prevention of PJP, with no cases of PJP breakthrough and minimal side effects during administration.  Intravenous PEN should be considered as an alternative to PJP prophylaxis with TMP-SMX, and in situations where other agents may be contraindicated.  Our findings support prospective studies of IV PEN in adult allogeneic HSCT recipients.