Photo by Chad McNeeley
SAN DIEGO—A retrospective study has revealed a few factors that may predict outcomes of allogeneic hematopoietic stem cell transplant (allo-HSCT) in adults with acute lymphoblastic leukemia (ALL).
The study showed that cytogenetics at diagnosis did not impact survival rates, although having high-risk cytogenetics was associated with an increased incidence of relapse in patients who were transplanted in their first complete remission (CR1).
Patients who were not in CR1 at transplant tended to have worse survival and higher relapse rates.
And patients who received a tacrolimus/sirolimus-based regimen as graft-vs-host disease (GVHD) prophylaxis had better survival rates than their peers, but their relapse rates did not differ.
Ibrahim Aldoss, MD, of City of Hope Medical Center in Duarte, California, presented these findings at the 2015 BMT Tandem Meetings as abstract 69.*
Dr Aldoss said there is a lack of data addressing individual ALL-related prognostic factors for transplant outcomes. So he and his colleagues decided to analyze 358 adult ALL patients who received allo-HSCT at the City of Hope from January 2004 through March 2014.
The patients’ median age was 38 (range, 18 to 72), and most patients (91%) had B-cell disease. At diagnosis, 2% of patients had good-risk cytogenetics, 43% had intermediate-risk, and 46% had poor-risk. For 9% of patients, the cytogenetic risk group was unknown.
At transplant, 60% of patients were in CR1, 17% were in CR2, and 23% were in a subsequent CR or had refractory disease.
Most patients received peripheral blood stem cell transplant (86%), 7% of patients received bone marrow, and the same percentage received cord blood. Fifty-four percent of patients had a matched sibling donor, 45% had an unrelated donor, and 1% had a related donor.
Eighty-one percent of patients received myeloablative conditioning, and the same percentage received a tacrolimus/sirolimus-based regimen for GVHD prophylaxis.
The 3-year estimated overall survival (OS) rate was 54%, leukemia-free survival (LFS) was 47%, and the cumulative incidence of relapse (CIR) was 27%. The 1-year non-relapse mortality (NRM) rate was 19%.
In multivariable analyses, disease status at allo-HSCT was an independent predictor of OS, LFS, and CIR. For OS, when the researchers compared patients in CR1 to those in CR2, the hazard ratio (HR) was 1.87 (P<0.01). When patients in CR1 were compared to other patients, the HR was 2.79 (P<0.01).
For LFS, the HRs were 1.69 (P=0.02) for CR1 vs CR2 and 2.94 (P<0.01) for CR1 vs others. And for CIR, the HRs were 2.21 (P<0.01) and 3.55 (P<0.01), respectively.
The analyses also revealed that tacrolimus/sirolimus-based GVHD prophylaxis was an independent predictor of OS, LFS, and NRM. The HRs were 1.58 (P=0.03), 1.5 (P=0.03), and 1.75 (P=0.03), respectively.
“So cytogenetics at diagnosis did not impact overall survival or leukemia-free survival among adult ALL patients who underwent allogeneic stem cell transplantation,” Dr Aldoss said in closing. “However, high-risk cytogenetics was associated with an increased cumulative incidence of relapse in patients transplanted in CR1.”
“Non-CR1 status at the time of transplant adversely affected overall survival, leukemia-free survival, and cumulative incidence of relapse. And a tacrolimus/sirolimus-based GVHD prophylaxis regimen was associated with improved overall survival, leukemia-free survival, and non-relapse mortality but did not influence the cumulative incidence of relapse.”
*Information in the abstract differs from that presented at the meeting.