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2862 Outcomes of Paediatric Acute Promyelocytic Leukaemia in the UK

Program: Oral and Poster Abstracts
Session: 613. Acute Myeloid Leukemias: Clinical and Epidemiological: Poster II
Hematology Disease Topics & Pathways:
Research, Acute Myeloid Malignancies, epidemiology, APL, Clinical Research, pediatric, Diseases, Myeloid Malignancies, Study Population, Human
Sunday, December 10, 2023, 6:00 PM-8:00 PM

Aditi Vedi, MBBS1,2*, Irum Memon3*, Else Van Risjik4*, Urmila Uparkar4*, Geofffrey Shenton5*, Amélie Trinquand6*, Katherine Clesham, MBBS, FRPATH7*, Vanessa Mclelland8*, Helen Jane Campbell, FRCP, MD, FRCPath9*, Katharine Patrick10*, Lyndsey Thompson11*, Susan Baird12*, Philip Connor13* and Beki James14*

1Paediatric Haematology/Oncology, Cambridge University Hospitals, Cambridge, United Kingdom
2Department of Paediatrics, University of Cambridge, Cambridge, United Kingdom
3Great Ormond Street Hospital, London, United Kingdom
4Royal Marsden Hospital, London, United Kingdom
5Royal Victoria Infirmary, Newcastle Upon Tyne, ENG, GBR
6Children’s Health Ireland (CHI) at Crumlin, Crumlin, D12 N512, Dublin, IRL
7UCL Great Ormond Street Hospital for Children, London, GBR
8University Hospital Bristol, Bristol, United Kingdom
9Astmoore Industrial Estate, Cheshire, GBR
10Sheffield Children's NHS Foundation Trust, Sheffield, United Kingdom
11Belfast Hospital, Belfast, United Kingdom
12Royal Hospital for Children and Young People, Edinburgh, United Kingdom
13Children's Hospital For Wales, Cardiff, GBR
14Leeds Teaching Hospital NHS Trust, Leeds, United Kingdom

Acute Promyelocytic Leukaemia (APL) is characterized by unique genetic and molecular abnormalities, clinical features, and treatment strategies. It accounts for 5-10% of paediatric acute myeloid leukaemia (AML) cases. APL is defined by the t(15;17)(q24;q21) chromosomal translocation, leading to the formation of the PML-RARA fusion protein, which plays a crucial role in leukemogenesis. All-trans retinoic acid (ATRA) has revolutionized APL management by targeting the PML-RARA fusion protein and inducing complete remission in the majority of patients. Arsenic trioxide (ATO) has emerged as an effective therapeutic agent, particularly in cases with ATRA resistance or relapse. ATO is now widely recommended as part upfront treatment. However, access to ATO has been limited by funding sources in certain countries.

This retrospective national study presents the treatment strategies, complications, and survival outcomes of 50 paediatric patients, aged 1 to 18 years, diagnosed with APL in the UK over an 8-year period, between 1st November 2014 and 31st October 2021. There were 21 (42%) high risk (HR) patience and 29 (58%) non-HR patients in the cohort. The majority of patients received a chemotherapy-free regimen comprising ATRA and ATO, with additional agents used selectively. Chemotherapy was usually given to patients in the event of lack of access to ATO or clinical urgency. Availability to ATO varied between countries within the UK.

Event-free survival (EFS) and overall survival (OS) were evaluated, with a minimum 2 years follow up from diagnosis and median follow-up of 8 years. Overall, the cohort demonstrated a high OS of 94%, with no significant difference observed between HR and non-HR patients. However, HR patients experienced significantly lower EFS, with all relapses occurring in this group. Relapsed patients received varied treatment regimens, including ATRA, ATO, and chemotherapy, with favourable outcomes.

This study contributes valuable insights into the management and outcomes of paediatric APL in the UK, emphasizing the importance of early diagnosis and risk stratification for optimal treatment decisions. Addressing disparities in ATO availability and promoting consistent funding across NHS Trusts will be crucial in further improving patient outcomes and reducing relapse rates in APL. Future research should focus on refining treatment protocols and exploring novel therapeutic strategies to enhance the long-term survival of paediatric APL patients. The study highlights the challenges associated with ATO availability across NHS Trusts, impacting treatment decisions and outcomes for APL patients.

Disclosures: No relevant conflicts of interest to declare.

*signifies non-member of ASH