A cancer center has seen improved outcomes of allogeneic transplant in recent years, despite increases in patient age and comorbidities.
Dr. George B. McDonald
Researchers compared patients who received allogeneic hematopoietic cell transplants (allo-HCTs) during two periods, 2003-2007 and 2013-2017.
Patients treated in the 2013-2017 period were older and had more HCT-specific comorbidities at baseline, but they had lower rates of mortality, relapse, and graft-versus-host disease (GVHD) post transplant. George B. McDonald, MD, an emeritus member at Fred Hutchinson Cancer Research Center in Seattle, and coauthors described these findings in Annals of Internal Medicine.
“The primary question being addressed by this study was whether the striking improvement in survival … from the 1990s to the early 2000s, that we and other transplant centers have reported, had reached a plateau or whether further improvements in survival were being seen,” Dr. McDonald said in an interview.
“We knew that older and sicker patients were now coming for transplant, compared to 10 years ago. Our transplant protocols have backed away from the highest doses of chemotherapy and irradiation used to prepare patients for transplant, toward less toxic therapies, including reduced-intensity conditioning,” he added. “Our investigators have sought to prevent and more effectively treat the myriad of complications of allogeneic transplant, based on research done at the Fred Hutchinson Cancer Research Center and at transplant centers throughout the world.”
Baseline characteristics and treatment
Dr. McDonald and his colleagues analyzed data on patients who received allo-HCTs at Seattle Cancer Care Alliance. There were 1,148 patients treated in the 2003-2007 period and 1,131 patients treated in the 2013-2017 period.
Indications for allo-HCT were similar between the time periods. Patients were diagnosed with aplastic anemia, acute and chronic leukemias, Hodgkin and non-Hodgkin lymphomas, myelodysplastic syndromes, and multiple myeloma.
Patients in the 2013-2017 group were older and had more HCT-specific comorbidities than did the patients in the 2003-2007 group. The median age was 50.0 years (range, 0.1-80.9 years) and 47.2 years (range, 0.4-78.9 years), respectively. The median score on the augmented HCT-specific comorbidity index was 4.0 and 3.0, respectively.
The 2013-2017 group was more likely to have intermediate-risk disease (73% vs. 54%) but less likely to have high-risk disease (14% vs. 31%). The 2013-2017 group was less likely to receive high-dose myeloablative conditioning (15% vs. 67%) but more likely to have an unrelated donor (70% vs. 59%) or receive a cord blood transplant (13% vs. 4%).
GVHD prophylaxis differed between the time periods, with patients in the 2013-2017 group being more likely to receive sirolimus, posttransplant cyclophosphamide, and abatacept.
Outcomes
Overall, outcomes were superior in the 2013-2017 group. The rate of nonrelapse mortality at day 200 was higher in the 2003-2007 group than in the 2013-2017 group – 16% and 11%, respectively (adjusted hazard ratio, 0.66; P = .008).
Relapse or progression was more common in the 2003-2007 group – 348 patients vs. 244 patients (aHR, 0.76; P = .011). More patients died from relapse in the 2003-2007 group – 307 patients vs. 186 patients (aHR, 0.69; P = .002). More patients died from any cause in the 2003-2007 group – 653 patients vs. 418 patients (aHR, 0.66; P less than .001). The rate of grade 2-4 acute GVHD was higher in the 2003-2007 group – 71% vs. 69% (aHR, 0.80) – and so was the rate of chronic GVHD – 44% vs. 29% (aHR, 0.40). The risk of developing gram-negative bacteremia was lower in the 2013-2017 group (aHR, 0.42), as was the risk of invasive mold infection (aHR, 0.55).
Patients in the 2013-2017 group had a higher risk of cytomegalovirus (CMV) infection (aHR = 1.15), but they were less likely to have high levels of CMV viremia (aHR, 0.78 for greater than 250 IU/mL; aHR, 0.46 for greater than 1,000 IU/mL). Having higher levels of CMV viremia was associated with an increased risk of non-relapse mortality.