PB1667 A META-ANALYSIS OF OUTCOMES IN ADULT PATIENTS UNDERGOING HSCT
Authors: Z. Rainford, M. Bennetts, M. Dilleen, D. Nickens, C. Ollis-Smith, S. Purcell
Journal: HemaSphere (2019)

Background: The treatment of acute lymphoblastic leukaemia (ALL) in adults poses a challenging treatment question for clinicians. While the majority of patients will achieve a complete remission, most will also relapse, with relapsed/refractory survival at 5 years less than 10%. Haematopoietic stem cell transplant (HSCT) remains the only real curative treatment option and recent advances in the number of available treatments for patients post relapse has increased the number of patients eligible to receive HSCT. Outcomes following transplantation in ALL can vary greatly and are affected by patient- or centre-specific factors such as age, conditioning regimen and stem cell source. There is currently limited data illustrating the long term survival outcomes of ALL transplant patients and how this has changed over time or how outcomes vary with differing transplant practices. There is therefore a great requirement for further information concerning how to achieve the best outcomes for patients undergoing HSCT. Aims: Through this systematic literature review and meta-analysis we aim to investigate the relationship between type of HSCT and date of transplant on the overall survival rate (OSR) achieved by ALL patients treated with allogeneic HSCT. Methods: A systematic literature review of studies in adult ALL was conducted using a comprehensive search of OVID MEDLINE(R) 1946-present, OVID MEDLINE(R) In-Process & Epub Ahead of Print and Embase according to the PICOS framework. Studies in adult ALL patients were included while other haematological malignancies, Japanese and paediatric populations were excluded. Only randomised clinical trials and registry data where the intervention/comparator was allogeneic HSCT were included. Case reports, reviews and studies with less than 3 years survival follow up or not in the English language were excluded. Only studies reporting overall survival rate (OSR) are discussed here. 13 studies were identified and included in a model-based meta-analysis to compare the survival outcomes of allogeneic HSCT, which included 23 donor arms, representing 2205 patients. OSR data at 3, 4 or 5 years were reported as percentages in the publications and were converted into binomial probabilities for the meta-analysis. Study start date was used to represent the first transplant year methodology. A logistic regression of the survival rate, weighted by study variance, was performed including additive terms in the model for transplant type: Cord, Mixed, Sibling, Unrelated Donor (URD) and first transplant year. The model estimates were back-transformed to give probabilities of overall survival. Results: The term for first transplant year was a significant predictor of survival in the model (p < 0.01 for 3 and 5 year data combined). There is an increase in survival with an increase in the year of first transplant. No significant differences were observed in outcomes between the donor types.Summary/Conclusion: A relationship between survival and first year of transplant has been demonstrated, with survival improving over time. However, a great heterogeneity was observed between the trial groups, end points and data reporting. This makes any robust analysis of the data challenging. Standardisation of study endpoints would aid cross-trial comparison and therefore enable analysis of larger cohorts of patients.