Incidence of hypersensitivity reactions (HSRs) to albumin-bound paclitaxel (ABI) in patients (pts) with a history of HSR to cremophor-based paclitaxel (P).

2566 Background: ABI is a cremophor-free formulation of paclitaxel which has been reported to have a lower incidence of HSRs. A retrospective evaluation was performed to determine the incidence of HSRs to ABI in pts with a history of HSRs to P. METHODS A query of the institutions medication database was performed to identify pts who received ABI during the evaluation period 2/05 - 5/09. A waiver of authorization was obtained to review the medical records. RESULTS At the discretion of the physician, 69 pts were switched to ABI following an HSR to P. Cancer diagnoses were 92% breast and 8% lung. The median age was 50 years and 92% were female. All pts who experienced an HSR to P had received premedication with corticosteroids, histamine 1 and histamine 2 antagonists. Pts' HSRs to P were grade 3 (1%), grade 2(74%) and grade 1 (25%) according to CTCAE 4 .03. The most common manifestations of HSRs to P were flushing 50%, shortness of breath 20%, chest tightness 18% and lower back pain 17%. The most common treatments to HSRs from P were stopping the infusion 81%, diphenhydramine IV (53%), hydrocortisone IV (30%) and dexamethasone IV (14%). Following the initial HSR to P, 30% of pts were rechallenged with P where 67% were able to complete the infusion at a slower rate while 33% developed a grade 1 or 2 HSR upon rechallenge. Of the 69 pts switched to ABI, 64 (93 %) did not experience a subsequent HSR. Twenty two (68%) of pts did not receive any premedication prior to the ABI challenge. Of the 5 pts who experienced an HSR to ABI, 2 were grade 1 and 3 were grade 2. Two of the five ABI HSR pts had been premedicated prior to the ABI challenge. The most common manifestations of HSRs to ABI were flushing and rash. Four of the 5 pts experienced the HSR during or immediately following the first dose of ABI. Four of these 5 pts were re-challenged with ABI and all 4 continued to receive further treatment courses after the reaction manifestations resolved. CONCLUSIONS The majority of pts with a history of grade 1 or 2 HSR to P could receive ABI without developing an HSR. Of those who reacted to ABI, reactions were tolerable and most were able to be re-challenged and continue treatment with ABI.