|The following article features coverage from the American Society of Clinical Oncology 2020 meeting. Click here to read more of Hematology Advisor’s conference coverage.|
Researchers have developed a validated pediatric disease risk index (p-DRI) for acute myeloid (AML) and acute lymphoblastic leukemia (ALL) that successfully stratifies children undergoing allogeneic hematopoietic cell transplantation for prognostication.
The results were presented by Muna Qayed, MD, of Emory University, in Atlanta, Georgia, at the ASCO20 Virtual Scientific Program.
Data from pediatric patients with AML (1135 patients) and ALL (1228 patients) who were transplanted between 2008 and 2017 in the United States were included in the study. Separate analyses were performed for each disease. Patient data was randomly assigned (1:1) to a training cohort or a validation cohort.
Cox regression models identified significant characteristics that were then used to develop the prognostic scoring system using the training cohort. The scoring system was subsequently applied to the validation cohort. The primary outcome was leukemia-free survival (LFS).
In patients with AML, the training cohort (568 patients) and validation cohort (567 patients) were similar in patient and disease characteristics. Most patients in the training and validation cohorts were over the age of 3 years (74%, both cohorts), had a comorbidity score less than or equal to 2 (82% and 83%, respectively), and intermediate or poor risk cytogenetics (89% and 90%, respectively).
Disease status at transplantation was categorized by complete remission and minimal residual disease (MRD) status. Over one-third of patients in both cohorts (36%) were in first complete remission (CR) with negative MRD, all other patients had positive MRD, were in second CR, or had active relapse.
Four risk groups were identified for AML based on the probability of LFS: good (28 patients; hazard ratio [HR], 1.00; P <.001), intermediate (222 patients; HR, 2.47; P =.048), high (188 patients; HR, 3.68; P =.005) and very high risk (83 patients; HR, 8.45; P <.0001). Most patients were in the Iintermediate (39%) and high-risk (33%) groups. The results for the validation cohort were nearly identical, with a Brier score of 0.169.
The 5-year probabilities of LFS for AML (validation cohort) were 81%, 55%, 42%, and 24% for good, intermediate, high, and very high-risk groups, respectively (P <.001).
For ALL, the training cohort (614 patients) and validation cohort (614 patients) were also similar in patient and disease characteristics. Most patients in the training and validation cohorts were over the age of 2 years (94% and 95%, respectively) and had a comorbidity score that is less than or equal to 2 (82% and 85%, respectively). For both cohorts, approximately 40% were in second CR and MRD negative, while approximately 25% were in first CR and MRD negative.
Three risk groups were identified for ALL based on the probability of LFS: good (197 patients; HR, 1.00; P <.0001), intermediate (372 patients; HR, 1.51; P =.004), high risk (11 patients; HR, 5.22; P <.0001). The results for the validation cohort were similar, with a Brier score of 0.158.
The 5-year probabilities of LFS for patients with ALL in the validation cohort were 72%, 50%, and 11% for good, intermediate, and high-risk groups (P <.001), respectively.
Lastly, the researchers applied the scoring system for prognostication of overall survival in both validation cohorts. It successfully stratified children with both AML (good: 25 patients; HR, 1.00; P <.0001; intermediate: 212 patients; HR, 3.52; P =.033; high: 207 patients; HR, 4.67; P =.009; very high risk: 82 patients; HR, 8.62; P =.0003) and ALL (good: 225 patients; HR, 1.00; P <.0001; intermediate: 353 patients; HR, 2.16; P <.0001; high: 9 patients; HR, 3.86; P =.004).
“The components included in the scoring system used information that is readily available pretransplantation, lending support to the deliverability of the prognostic scoring system. It can further be used for improved interpretation of multicenter data and in clinical trials for risk stratification,” concluded Dr Qayed.
Qayed M, Kitko CL, Ahn KW, et al. Development and validation of a pediatric disease risk index for allogeneic hematopoietic cell transplantation. Presented at: ASCO20 Virtual Scientific Program. J Clin Oncol. 2020;38(suppl):abstr 7503.