Retrospective Evaluation of Palivizumab Efficacy and Safety for RSV Prophylaxis in Pediatric Hematopoietic Stem Cell Transplant Patients: A Single Center Experience

Palivizumab, an antiviral agent which neutralizes and exhibits fusion-inhibitory activity against respiratory syncytial virus (RSV), is currently recommended by the American Academy of Pediatrics (AAP) as prophylaxis for RSV in immunocompromised children less than 24 months of age. However, the recommendation is based on consensus opinion and is limited due to the insufficient evidence investigating the use of palivizumab prophylaxis in immunocompromised children. For pediatric hematopoietic stem cell transplant (HSCT) patients, the practice at Memorial Sloan Kettering Cancer Center (MSK) has been: (1) to perform a nasopharyngeal swab for viral PCRs including RSV in any patient with any or all of the three symptoms: rhinorrhea, cough, wheezing, (2) to administer prophylactic palivizumab to all pediatric HSCT patients during RSV season based on select criteria: younger age, prior history of pulmonary complications, recipients of HLA-mismatched transplants and/or of T-cell depleted (TCD) transplants, presence of graft versus host disease (GVHD), and (3) to administer palivizumab intravenously (IV) instead of intramuscularly. A retrospective chart review was conducted at MSK and included patients who underwent HSCT on the pediatric transplant service from January 1, 2009 to November 30, 2014. A total of 275 patients met inclusion criteria and were evaluated for prior prophylactic use of IV palivizumab versus no prophylaxis. As shown in Table 1, 128 of 275 patients received palivizumab prophylaxis while 147 patients did not. Forty-six patients (16.7%) had at least one RSV positive swab, including 40 patients in the palivizumab prophylaxis patient cohort, 12 (9.4%) of whom were dosed within the month prior to the swab and considered true prophylaxis failures. In comparison, 6 (4.0%) of 147 patients in the non-prophylaxis group had RSV positive swabs. Out of the 275 patients, 2 (0.7%) were hospitalized and 1 (0.4%) was admitted to the PICU. All 3 patients were in the palivizumab prophylaxis failure group. Table 1All patientsPalivizumab prophylaxisNo prophylaxisN275128147RSV + Patients46 (16.7%)40 (31.0)6 (4.0%)RSV + swab 1 month post-dose1212 (9.5%)NARSV Admissions330 Open table in a new tab A total of 311 doses of palivizumab were administered IV with only 1 documented adverse reaction, specifically a fever which led to the discontinuation of the infusion. In summary, intravenous palivizumab did not appear to decrease the incidence of RSV post transplant for pediatric HSCT patients. All 46 pediatric HSCT patients who had positive swabs for RSV did well with only 3 admissions and no mortality. All three admissions were in the high-risk patient group who also received palivizumab prophylaxis. IV palivizumab was found to be safe with only one adverse event occurring out of 311 doses, which demonstrates a possible alternative route of administration for larger volumes of palivizumab in older children.