Preemptive Immunotherapy for Minimal Residual Disease in Patients With t(8;21) Acute Myeloid Leukemia After Allogeneic Hematopoietic Stem Cell Transplantation

Avapritinib is effective for treatment of minimal residual disease in acute myeloid leukemia with t (8;21) and kit mutation failing to immunotherapy after allogeneic hematopoietic stem cell transplantation

In patients with t(8;21) acute myeloid leukemia (AML) with recurrent measurable residual disease (MRD) after allogeneic hematopoietic stem cell transplantation (allo-HSCT), pre-emptive interferon-α therapy and donor lymphocyte infusion are noneffective in 30%-50% of patients. Avapritinib is a novel tyrosine kinase inhibitor targeting KIT mutations. We retrospectively report about 20 patients with t(8;21) AML and KIT mutations treated with avapritinib after allo-HSCT with MRD and most failing to respond to immunotherapy. Reduction of RUNX1-RUNX1T1 after 1 month of treatment was ≥1 log in 12 patients (60%), which became negative in 4 patients (20%). In 13 patients who received avapritinib for ≥3 months, the reduction was ≥1 log in all patients, which became negative in 7 patients (53.8%). The median follow-up time was 5.5 (2.0-10.0) months from avapritinib initiation to the last follow-up. Three patients underwent hematologic relapse and survived. Among all 20 patients, RUNX1-RUNX1T1 transcripts turned negative in 9 patients (45%). The efficacy did not differ significantly between D816 and non-D816 KIT mutation groups. The main adverse effect was hematological toxicity, which could generally be tolerated. In summary, avapritinib was effective for MRD treatment in patients with t(8;21) AML with KIT mutations failing to respond to immunotherapy after allo-HSCT.

Machine learning algorithm as a prognostic tool for Epstein-Barr virus reactivation after haploidentical hematopoietic stem cell transplantation

Epstein-Barr virus (EBV) reactivation is one of the most important infections after hematopoietic stem cell transplantation (HSCT) using haplo-identical related donors (HID). We aimed to establish a comprehensive model with machine learning, which could predict EBV reactivation after HID HSCT with anti-thymocyte globulin (ATG) for graft-versus-host disease (GVHD) prophylaxis. We enrolled 470 consecutive acute leukemia patients, 60% of them (n = 282) randomly selected as a training cohort, the remaining 40% (n = 188) as a validation cohort. The equation was as follows: Probability (EBV reactivation) =   1 1       +       e x p ( - Y ) , where Y = 0.0250 × (age) - 0.3614 × (gender) + 0.0668 × (underlying disease) - 0.6297 × (disease status before HSCT) - 0.0726 × (disease risk index) - 0.0118 × (hematopoietic cell transplantation-specific comorbidity index [HCT-CI] score) + 1.2037 × (human leukocyte antigen disparity) + 0.5347 × (EBV serostatus) + 0.1605 × (conditioning regimen) - 0.2270 × (donor/recipient gender matched) + 0.2304 × (donor/recipient relation) - 0.0170 × (mononuclear cell counts in graft) + 0.0395 × (CD34+ cell count in graft) - 2.4510. The threshold of probability was 0.4623, which separated patients into low- and high-risk groups. The 1-year cumulative incidence of EBV reactivation in the low- and high-risk groups was 11.0% versus 24.5% (P < .001), 10.7% versus 19.3% (P = .046), and 11.4% versus 31.6% (P = .001), respectively, in total, training and validation cohorts. The model could also predict relapse and survival after HID HSCT. We established a comprehensive model that could predict EBV reactivation in HID HSCT recipients using ATG for GVHD prophylaxis.

Anti-CD19 chimeric antigen receptor T-cell followed by interferon-α therapy induces durable complete remission in donor cell-derived acute lymphoblastic leukemia: A case report

Donor cell-derived leukemia (DCL) is a special type of relapse after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Patients with DCL generally have a poor prognosis due to resistance to conventional chemotherapy. Here, we report a case of donor cell-derived acute lymphoblastic leukemia after umbilical cord blood transplantation. The patient didn't respond to induction chemotherapy. She then received anti-CD19 CAR-T cell therapy and achieved MRD-negative complete remission (CR). However, MRD levels rose from negative to 0.05% at 5 months after CAR-T cell therapy. Higher MRD levels were significantly associated with an increased risk of leukemia recurrence. Afterward, preemptive interferon-α treatment was administrated to prevent disease recurrence. To date, the patient has maintained MRD-negative CR for 41 months. Our results suggested that anti-CD19 CAR-T cells followed by interferon-α therapy are effective in treating donor cell-derived acute lymphoblastic leukemia. This report provides a novel strategy for the treatment of DCL.

Immune Reconstitution of Patients Who Recovered From Steroid-Refractory Acute Graft-Versus-Host Disease After Basiliximab Treatment

We aimed to identify the characteristics of immune reconstitution (IR) in patients who recovered from steroid-refractory acute graft-versus-host disease (SR-aGVHD) after basiliximab treatment. A total of 179, 124, 80, and 92 patients were included in the analysis for IR at 3, 6, 9, and 12 months, respectively, after haploidentical donor hematopoietic stem cell transplantation (HID HSCT). We observed that IR was fastest for monocytes and CD8⁺ T cells, followed by lymphocytes, CD3⁺ T cells, and CD19⁺ B cells and slowest for CD4⁺ T cells. Almost all immune cell subsets recovered comparably between patients receiving <5 doses and ≥5 doses of basiliximab. Most immune cell subsets recovered comparably between SR-aGVHD patients who recovered after basiliximab treatment and event-free HID HSCT recipients. Patients who recovered from SR-aGVHD after basiliximab treatment experienced satisfactory IR, which suggested that basiliximab may not have prolonged the negative impact on IR in these patients.

A Predicted Model for Refractory/Recurrent Cytomegalovirus Infection in Acute Leukemia Patients After Haploidentical Hematopoietic Stem Cell Transplantation

Objective

We aimed to establish a model that can predict refractory/recurrent cytomegalovirus (CMV) infection after haploidentical donor (HID) hematopoietic stem cell transplantation (HSCT).

Methods

Consecutive acute leukemia patients receiving HID HSCT were enrolled (n = 289). We randomly selected 60% of the entire population (n = 170) as the training cohort, and the remaining 40% comprised the validation cohort (n = 119). Patients were treated according to the protocol registered at https://clinicaltrials.gov (NCT03756675).

Results

The model was as follows: Y = 0.0322 × (age) – 0.0696 × (gender) + 0.5492 × (underlying disease) + 0.0963 × (the cumulative dose of prednisone during pre-engraftment phase) – 0.0771 × (CD34+ cell counts in graft) – 1.2926. The threshold of probability was 0.5243, which helped to separate patients into high- and low-risk groups. In the low- and high-risk groups, the 100-day cumulative incidence of refractory/recurrent CMV was 42.0% [95% confidence interval (CI), 34.7%–49.4%] vs. 63.7% (95% CI, 54.8%–72.6%) (P &lt; 0.001) for total patients and was 50.5% (95% confidence interval (CI), 40.9%–60.1%) vs. 71.0% (95% CI, 59.5%–82.4%) (P = 0.024) for those with acute graft-versus-host disease. It could also predict posttransplant mortality and survival.

Conclusion

We established a comprehensive model that could predict the refractory/recurrent CMV infection after HID HSCT.

Clinical Trial Registration

https://clinicaltrials.gov, identifier NCT03756675.