PB2349 EXTRACORPOREAL PHOTOPHERESIS FOR PEDIATRIC PATIENTS WITH GRAFT‐VS‐HOST DISEASE AFTER HAEMATOPOIETIC STEM CELL TRANSPLANTATION: AN AUSTRALIAN EXPERIENCE

Abstract

Background:Graft‐versus‐host disease (GVHD) remains a major cause of morbidity and mortality following pediatric allogeneic hematopoietic stem cell transplant (HSCT). Extracorporeal photopheresis (ECP) is a cellular immuno‐modulatory therapy licensed for the treatment of steroid‐dependent or refractory GVHD. ECP has been shown to be effective in the treatment of GVHD in the adult population, however there is little data in the pediatric setting. Here we present our Australian experience in paediatric patients with GVHD.Aims:To assess the outcome and feasibility of ECP as a treatment modality for GVHD in the pediatric allograft patients in Australia.Methods:A retrospective case note analysis of all patients receiving ECP for the treatment of GVHD between August 2010 and December 2018 at the Royal Children's Hospital and Peter MacCallum Cancer Centre, Victoria.Results:14 patients were identified, with a median age of 4.4 years (range 0.5‐14.8). Demographic and transplant characteristics are summarised in Table 1. ECP was used to treat both acute (aGVHD, n = 7) and chronic (cGVHD, n = 8) GVHD. One patient required two treatment episodes for acute and subsequently chronic GVHD. All patients were refractory to prior immunosuppressive therapy, with a median of 3 agents used (range 2‐5). Median steroid dose was 0.8 mg/kg/day methylprednisolone equivalent (range 0‐2). An overall response was obtained in 6 of 7 (86%) acute and 6 of 8 (75%) chronic GVHD patients. Overall survival was 79% (11 of 14 patients).Of those treated for aGVHD varying from grade II – IV, 86% (n = 6) showed a partial response or better, with 43% (n = 3) achieving a complete response. Median steroid dose was reduced by 94% from 1.8 mg/kg/day methylprednisolone equivalent to 0.1 mg/kg/day from beginning to end of ECP. ECP duration was a median of 1.9 months (range 1.4‐5.7), with a median of 16 treatments (range 12‐25).The majority of cGVHD patients had extensive disease (n = 7, 88%), with 75% (n = 6) achieving at least a partial response, with a complete response in 37.5% (n = 3). Median steroid dose was reduced by 88% from 0.18 mg/kg/day methylprednisolone equivalent to 0.02 mg/kg/day from beginning to end of ECP. ECP was used for a median period of 7.1 months (range 1.9‐39.1) with a median of 25 treatments (range 7‐61).Catheter‐related sepsis was the most common reason for premature discontinuation of ECP in our cohort, occurring in 6 patients (43%). Other noted complications included haemodynamic instability requiring admission, occurring in 3 patients (21%). This caused discontinuation of ECP in one patient weighing 7.5 kg. Of the 3 patients who died, two had grade IV aGVHD with progressive disease post‐ECP, and one with refractory extensive cGVHD. The causes of death were sepsis (n = 2) and relapsed primary malignancy (n = 1).Summary/Conclusion:This is the first report of ECP therapy in Australia for pediatric patients with GVHD. Our results demonstrate that ECP is an effective and feasible treatment modality for both acute and chronic GVHD post‐HSCT. In our cohort, ECP allowed for tapering of corticosteroids, which has been shown to be associated with improved survival. Although ECP was well tolerated overall, specific consideration should be given when used in the pediatric population, especially with regard to the risk of haemodynamic instability, the use of blood prime of the circuit and catheter‐related sepsis.image