Photo by Chad McNeeley
HSCT preparation
Results of a phase 3 trial revealed similar outcomes in patients who underwent allogeneic hematopoietic stem cell transplant (HSCT) to treat myelodysplastic syndromes (MDS), regardless of the conditioning regimen they received.
Rates of engraftment, graft-vs-host disease (GVHD), relapse, and survival were similar between patients who received reduced-intensity conditioning (RIC) and those who received standard myeloablative conditioning (MAC) before HSCT.
Researchers reported these results in the Journal of Clinical Oncology.
“Our study shed new light on expected benefits of a reduced-intensity conditioning regimen that can be offered as a curative treatment approach, especially in older patients with MDS,” said study author Nicolaus Kröger, MD, of University Hospital Eppendorf in Hamburg, Germany.
Patient characteristics
The study, known as RICMAC, involved 129 patients who underwent HSCT between May 2004 and December 2012 at 18 transplant units in 7 countries.
Patients were randomized in a 1:1 ratio to RIC (n=65) or MAC (n=64) and were stratified according to donor type, age, and blast count.
The median age was 50 (range, 19-64) in the MAC arm and 51 (range, 22-63) in the RIC arm. The median blast percentage was 4% (range, 0-18) and 5% (range, 0-18), respectively.
According to IPSS, most patients in both arms had intermediate-I-risk disease (28 MAC, 25 RIC) or intermediate-II-risk disease (18 MAC, 24 RIC).
Similar numbers of patients in each arm had low cytogenetic risk (24 MAC, 28 RIC), intermediate cytogenetic risk (17 MAC, 13 RIC), and high cytogenetic risk (17 MAC, 18 RIC).
Thirty-three patients in the MAC arm and 32 in the RIC arm received ATG as GVHD prophylaxis.
Patients received grafts from matched related donors (17 MAC, 16 RIC), matched unrelated donors (36 MAC, 38 RIC), or mismatched related/unrelated donors (11 in both arms).
Most patients received peripheral blood stem cell grafts—61 in the MAC arm and 59 in the RIC arm.
Results
The researchers said engraftment was comparable between the arms. There were 4 graft failures in the MAC arm and 3 in the RIC arm (P=0.72). The median time to leukocyte engraftment was 15 days in both arms. The median time to platelet engraftment was 15 days in the RIC arm and 16 in the MAC arm (P=0.33).
There was no significant difference in the cumulative incidence of GVHD between the RIC and MAC arms:
- Grade 2-4 acute GVHD—32.3% and 37.5%, respectively
- Grade 3-4 acute GVHD—15% and 14%, respectively (P=0.35 for between-arm difference for all acute GVHD)
- Chronic GVHD—61.6% and 64.7%, respectively (P=0.76).
Though the occurrence of infection was similar between the MAC and RIC arms (48 and 44, respectively), the rate of infection was higher in the MAC arm than the RIC arm.
The rate of infection in the first 100 days was 6.9 per 100 person-years in the MAC arm and 4.3 in the RIC arm (P=0.002). The rate of infection during the total follow-up was 2.0 per 100 person-years in the MAC arm and 1.4 in the RIC arm (P=0.002).
There was no significant difference between the RIC and MAC arms with regard to the cumulative incidence of nonrelapse mortality after 1 year—16.9% and 25.3%, respectively (P=0.29).
And there was no significant difference in the cumulative incidence of relapse at 2 years—17% and 14.8%, respectively (P=0.6).
The 2-year relapse-free survival rate was similar in the MAC and RIC arms—58.3% and 62.4% (P=0.58)—as was the 2-year overall survival rate—63.2% and 76.3%, respectively (P=0.08).
