Allogeneic hematopoietic stem cell transplantation in r/r Hodgkin lymphoma after treatment with checkpoint inhibitors: Feasibility and safety.

OBJECTIVES: Relapsed cHL patients after autologous hematopoietic stem cell transplantation (HSCT) with treatment-sensitive disease are potential candidates for curative allogeneic HSCT. However, there are some concerns around performing such procedure after checkpoint inhibitors (CPIs).

METHODS: We collected published data of patients undergoing allogeneic HSCT after treatment with CPIs (cohort 1). Abstracts of recent conferences (2015-2017; ASCO, ASH, EBMT, ASBMT) were also included. Results were compared with safety of recent studies (2015-2018) with allogeneic HSCT without CPIs (cohort 2).

RESULTS: A total of 272 records were screened. After exclusion of duplications, cohorts 1 and 2 included each 6 publications with 122 and 978 patients, respectively. Grade 3-4 acute GVHD in cohort 1 was found in 28% vs 8% in cohort 2 (P = 0.02). Chronic GVHD was observed in 26% vs 29%, respectively. NRM was 15% which remained relatively stable after 6 months of allogeneic HSCT vs 19% in cohort 2.

CONCLUSIONS: This is the largest pooled analysis of its kind published so far. Our results suggest that allogeneic HSCT after CPIs is feasible and not associated with higher mortality. However, careful consideration should be given for prevention, early detection, and effective treatment of GVHD in these cases. Additional prospective studies are needed for further clarification.