Transplant outcomes with alternative donors in MF: A Japanese Registry analysis

Allogeneic HSCT (allo-HSCT) is the only curative treatment for myelofibrosis (MF). Historically, the preferred donor type for allo-HSCT was HLA-MRD due to superior outcomes. More recently, alternative donors have demonstrated improved transplant outcomes. However, data on the impact of alternative donors in MF are limited. Sakatoku et al. published a Japanese retrospective analysis in the American Journal of Hematology evaluating the transplant outcomes with alternative donors in patients with MF who underwent allo-HSCT between 2000 and 2019.¹

The analysis comprised an early cohort (2000–2012) and late cohort (2013–2019). Four donor types: MRD (n = 95), MUD (n = 97), MMUD (n = 65), and CB (n = 51) were evaluated. 

Key learnings²

Across all four donor types, there were no differences in the cumulative incidence of Grade 2–4 aGvHD (p = 0.712 vs 0.793), Grade 3–4 aGvHD (p = 0.169 vs 0.866), and cGvHD (p = 0.196 vs 0.932) between the early vs late cohort.

The 28-day neutrophil engraftment rates in the early vs late cohort were 90.6% vs 84.6% for MRD, 61.3% vs 79.7% for MUD, 78.6% vs 73.3% for MMUD, and 50.0% vs 65.4% for CB, respectively.

In the MVA, neutrophil engraftment was less frequent in MUD (HR 0.43; p < 0.001), MMUD (HR 0.43; p = 0.002), and CB (HR 0.19; p < 0.001) in the early cohort, and in CB in the late cohort (HR 0.50; p = 0.017), compared with MRD.

In the early vs late cohort, 3-year NRM rates were 14.8% vs 23.8% for MRD, 27.0% vs 27.6% for MUD, 40.0% vs 25.2% for MMUD, and 37.0% vs 23.5% for CB, respectively.

In the early cohort, NRM was higher for MUD (HR 2.28; p = 0.061), MMUD (HR 2.96; p = 0.023), and CB (HR 4.45; p = 0.006) in MVA compared with MRD.

The 3-year OS rates in the early vs late cohort were 58.9% vs 56.3% for MRD, 46.0% vs 48.7% for MUD, 35.0% vs 58.1% for MMUD, and 30.5% vs 60.6% for CB, respectively.

Older patients who received Rux had better 3-year OS (p = 0.02) and reduced Grade 3–4 aGvHD incidence (p = 0.056), while younger patients who received Rux had worse 3-year OS (p < 0.001), higher NRM (p = 0.015), and delayed neutrophil engraftment (p = 0.014). 

The analysis demonstrates that alternative donors can offer outcomes similar to HLA-MRD. These findings highlight the potential role of alternative donors in tailored age- and donor-specific strategies to optimize allo-HSCT outcomes in MF.