Outcomes appear similar with MAC and RIC

“Complete chimerism was achieved in all engrafted patients,” Dr Sugita noted.

There was no significant difference between MAC and RIC recipients when it came to acute or chronic GVHD.

At day 100, the cumulative incidence of grade 2-4 acute GVHD was 18% in the MAC group and 14% in the RIC group (P=0.52). Grade 3-4 acute GVHD was 8% and 5%, respectively (P=0.52).

At 2 years, the cumulative incidence of all-grade chronic GVHD was 36% in the MAC group and 27% in the RIC group (P=0.24). Moderate to severe chronic GVHD was 20% in both groups (P=1.0).

Relapse and survival

There was no significant between-group difference in NRM or relapse.

The cumulative incidence of NRM at 2 years was 20% in the RIC group and 10% in the MAC group (P=0.15). The cumulative incidence of relapse at 2 years was 45% and 36%, respectively (P=0.32).

Survival was superior in the MAC recipients. The 2-year OS was 68% in the MAC group and 44% in the RIC group (P=0.02). The 2-year EFS was 54% and 35%, respectively (P=0.04).

However, survival appeared to be affected by history of allogeneic transplant.

“Patients with a history of prior allogenic SCT have significantly worse overall survival and event-free survival,” Dr Sugita said.

Two-year OS was 31% in RIC recipients with a history of transplant and 52% in RIC recipients without a history of transplant (P=0.04). The OS was 68% in MAC recipients, all of whom had no history of transplant.

Two-year EFS was 21%, 44%, and 54%, respectively (P=0.02 for difference between 2 RIC groups).

In a multivariate analysis, conditioning regimen was not a significant predictor of NRM. The hazard ratio (HR) for RIC was 1.13 (P=0.85).

Likewise, conditioning regimen was not a significant predictor of relapse (HR=0.81, P=0.53), OS (HR=0.85, P=0.66), or EFS (HR=0.73, P=0.34).

“Our results indicate that both MAC and RIC are valid options for PTCy-haplo,” Dr Sugita said in closing.

“Ideally, a more precise comparison of MAC and RIC should be studied further in the setting of, if possible, a randomized trial.” 

*Data in the abstract differs from the presentation.