Timing of allogeneic hematopoietic cell transplantation for myelofibrosis and other myeloproliferative neoplasms.

• DOI: 10.1200/jco.2024.42.16_suppl.e18517
• Publication Date: 2024-06-10T16:59:22Z
• Authors: Joshua S. Mercer; Claire I. Bradbury; Samantha M. Thomas; Sendhilnathan Ram...; Cristina Gasparetto; Taewoong Choi; Anthony D. Sung; Stefanie Sarantop...; Gwynn Douglas Long; Edwin Alyea; Mitchell E. Horwitz; Nelson Jen An Chao; Sanghee Hong
• Keywords: 03 medical and health sciences; 0302 clinical medicine

e18517 Background: Myeloproliferative neoplasms (MPN) and myelodysplastic syndrome (MDS)/MPN overlap syndromes are rare hematopoietic malignancies in which allogeneic hematopoietic cell transplantation (HCT) is the only treatment with curative potential. Even for higher risk patients, the optimal timing for HCT is largely unknown. We interrogated HCT outcomes of myelofibrosis (MF) and the rest of MPN, MDS/MPN overlap based on the timing of HCT from diagnosis (Dx) to help oncologists determine the optimal timing to refer patients for HCT. Methods: This retrospective, single-center study obtained data from our HCT database. We included adult (>18 years; y) patients who received their first allogeneic HCT between 2015 and 2022 for initial Dx of MPN or MDS/MPN overlap. We included all donor types and graft sources. Analysis was separated by MF vs. others (other MPN and MDS/MPN) to account for fibrotic vs proliferative nature of disease progression and sample size. The primary variable was the time from Dx to HCT. The primary endpoint was overall survival (OS) from HCT. Secondary endpoints were progression free survival (PFS) and non-relapse mortality (NRM) from HCT. Results: 46 patients (n=27 for MF, n=19 for others) were included. 59% were male (56% for MF, 63% for others). The median age at HCT for MF was 57y (range 45-72) and for others was 63y (32-75). For patients with MF and others, 85% and 84% received myeloablative conditioning, respectively. In the MF group, all patients had PBSC grafts and 37% of grafts were from match-related donors; in the others group, 89% had PBSC grafts (11% had BM grafts) and 53% of grafts were from match-related donors. The median time from Dx to HCT for patients with MF was 28 months (m; range 4-166) and for others was 11m (2-423). In the MF group, those whose HCT <1y from Dx had improved OS (Table) and PFS (1y, 83.3% vs. 53.3%, p=0.031) compared to HCT ≥1y after Dx. However, no differences were found in OS or PFS for <6m vs. >6m from Dx to HCT. No differences in OS/PFS were seen based on the timing of HCT in the others group. Conclusions: Patients with MF, but not with other MPN or MDS/MPN, who received allogenic HCT <1y from Dx had significantly improved OS and PFS. Our results suggest that early referral to HCT after confirmation of marrow fibrosis for higher risk MF may influence HCT outcomes positively. However, lack of improvement in OS/PFS at 6m suggests that addressing individual risks and initiating appropriate therapies for MF first may more effectively balance risks of post-HCT complication with disease progression. Additional studies investigating timing of HCT will help oncologists to direct management of MPN and MDS/MPN overlap. [Table: see text]