Incidence of Pneumocystis Jirovecii Infection and Duration of Prophylaxis After Allogeneic Stem Cell Transplantation

Allogeneic hematopoietic cell transplantation (alloHCT) recipients are at an increased for Pneumocystis jirovecii pneumonia (PCP) post-HCT. Current recommendations for alloHCT recipients includes a prophylactic regimen until at least six months post alloHCT or longer in patients receiving immune suppresive therapy (Tomblyn, BBMT 2009). The Infectious Disease Society of America guidelines recommend PCP prophylaxis continue in patients with HIV/AIDS until CD4+ counts are > 200/uL for more than 3 months. To assess duration of prophylaxis needed, we retrospectively evaluated 100 patients who received alloHCT for myeloid malignances between 2006 and 2011. Incidence of PCP infection and toxicity to prophylactic regimen were also evaluated.

Characteristics of the 100 patients are shown (Table 1). 66 patients received systemic steroids post-transplant and 26 patients received anti-thymocyte globulin (ATG) during conditioning. Primary PCP prophylaxis consisted of trimethoprim-sulfamethoxazole (TMP/SMX) (91%) or pentamadine (9%). Toxicity to first-line therapy did not occur in 61% of patients and for 7% of patients' toxicity status was unknown. Toxicity from TMP/SMX occurred in 32% of patients including hematologic (78%), dermatologic 6.3%, renal 3.1%, gastrointestinal 3.1%, and drug interaction 3.1%. At last contact 36% of patients had PCP prophylaxis discontinued with CD4+ count evaluated in 26 patients. At discontinuation in these patients, the mean CD4+ count was 411/ uL and only 5 patients had a CD4+ count < 200/uL. Median duration of PCP prophylaxis was 327 (26-2175) days in all patients evaluated, 369 (38-2175) days if alive at date of last contact (DLC) (n=55), 408 (141-2150) days in patients who completed prophylaxis and were alive at DLC, and 425 (127-2175) days if alive at DLC after receiving ATG (n=15). Median time to TMP/SMX toxicity was 29 (4-854) days. 74 patients continued on GVHD directed therapy at DLC. 20.3% of these patients had stopped PCP prophylaxis. One patient had PCP requiring hospital admission 146 days after HCT. This patient received myeloablative conditioning with ATG followed by mismatched unrelated donor HCT. At time of PCP infection, patient was on tacrolimus and 40mg of prednisone for GVHD treatment and was receiving pentamidine for PCP prophylaxis.

In summary, the incidence of PCP is rare in the post alloHCT population. Our data suggests PCP prophylaxis can be safely discontinued if CD4+ counts > 200/uL and if not on systemic steroids.

 

Variables	N = 100
Age at transplant, years, median (range)	51.8 (22-74)
Gender Male Female	51 49
Primary Diagnosis AML CML MDS MPS MYF	61 5 29 4 1
Received Systemic steroids Yes No	66 34
Received ATG Yes No	26 74
Conditioning Intensity Myeloablative Reduced intensity/non-myeloablative	92 8
Donor Type Matched related Matched unrelated Mismatched related Mismatched unrelated Umbilical cord blood	33 38 2 25 2