Younger Matched Unrelated Donors Confer Decreased Relapse Risk Compared to Older Sibling Donors in Older Patients with B Cell Acute Lymphoblastic Leukemia Undergoing Allogeneic Hematopoietic Cell Transplantation

Although allogeneic hematopoietic cell transplantation (alloHCT) offers cure for older patients with acute lymphoblastic leukemia (ALL), disease relapse remains a major issue. Whether matched sibling donors (MSDs) are still the preferred donor choice compared to younger matched unrelated donors (MUDs) in the contemporary era of improved transplantation practices remains unknown. This retrospective cohort registry study queried the Center for International Blood and Marrow Transplant Research (CIBMTR) database in patients with B cell ALL (B-ALL) age ≥ 50 years undergoing alloHCT from older MSDs (age ≥ 50 years) or younger MUDs (age ≤ 35 years) between 2011 and 2018. The study included common allograft types, conditioning regimens, and graft-versus-host disease (GVHD) prophylaxis strategies. The primary outcome was relapse risk, and secondary outcomes included nonrelapse mortality (NRM), GVHD, leukemia-free survival (LFS), and overall survival (OS). Among 925 eligible patients in the study cohort, 386 underwent alloHCT with an older MSD (median donor age, 58 years) and 539 underwent alloHCT from a younger MUD (median donor age, 25 year). In multivariable analysis, younger MUDs conferred a significantly decreased risk of relapse (hazard ratio [HR], .68; P = .002) compared with older MSDs. The adjusted cumulative incidence of relapse at 5 years was significantly lower with younger MUDs than with older MSDs (26% versus 37%; P = .001). Younger MUDs were associated with a greater risk of chronic GVHD compared to older MSDs (HR, 1.33; 95% confidence interval [CI], 1.10 to 1.61; P = .003). Compared to older MSDs, younger MUDs conferred an increased NRM (HR, 1.38; P = .02) and higher adjusted cumulative incidence of NRM at 5 years (31% versus 22%; P = .006). There were no differences in post-alloHCT OS or LFS rates between younger MUDs and older MSDs (OS: HR, 1.09; [P = .37]; LFS: HR, .95 [P = .57]). The use of younger MUDs could be considered as a possible way to prevent relapse after alloHCT in older adults with ALL. Combining the use of younger MUDs with improved strategies to reduce GVHD merits further exploration to improve outcomes.

250 Spatial-transcriptomic analysis of tumor-immune microenvironment in AML patients receiving pembrolizumab and decitabine

Background

Relapsed or refractory Acute Myeloid Leukemia (R-AML) is a deadly disease with an inadequate response rate to current treatments. Recent advances in immunotherapy shed light on R-AML, and several clinical trials have shown promising potential for combining immune checkpoint inhibitors (ICIs) with hypomethylating agents. A deeper understanding of the tumor-immune microenvironment in R-AML during combination ICI treatment is urgently needed for developing better therapeutics and stratifying treatment strategies.

Methods

To dissect the tumor-immune interactions in the bone marrow microenvironment, we employed nanoString GeoMx Digital Spatial Profiler (DSP) and performed a spatial-transcriptomic analysis of patients with R-AML who received pembrolizumab and decitabine. We compared the transcriptomic profiles and TCR clonalities of tumor-interacting T cells, bystander T cells, and other cells at baseline, post-pembrolizumab treatment, and post-decitabine, which enable us to identify R-AML’s suppressive immune microenvironment and immune cells’ responses to ICI and hypomethylating agent.

Results

We obtained the spatial-transcriptomic profiles of T cells, stromal cells, and leukemia cells in patients with R-AML at different treatment points. Our TCR-specific probes were able to track T cell clonal changes during treatments.

Conclusions

R-AML harbored a complex tumor immune microenvironment and diverse T cell clonality.

Acknowledgements

This research was supported in part by the Intramural Research Program of the NCI (the Center for Cancer Research), NHLBI, and NIH Clinical Center.

Ethics Approval

This study is approved by NHLBI IRB.

Randomized controlled trial of midazolam premedication to reduce the subjective adverse effects of adenosine

OBJECTIVE

To determine the safety and efficacy of midazolam premedication to minimize the subjective adverse effects of adenosine.

METHODS

Double-blind prospective randomized controlled trial of patients presenting to an urban emergency department. Included were a convenience sample of patients who would have received adenosine by the existing department protocol. Exclusion criteria were pregnancy, benzodiazepine allergy, regular benzodiazepine medication, alcoholism, altered mental state (precluding informed consent), and age less than 18 or greater than 65 years. Subjects received either 1.5 mg of intravenous midazolam or normal saline placebo 5 min prior to the administration of adenosine. Side-effect recall was judged by a questionnaire at 1 h and 24 h postadenosine administration.

RESULTS

A total of 34 patients were recruited into the trial, 16 in the placebo group and 18 in the midazolam group. The groups were well matched for demographics, treatment and outcome. There was a significant reduction in the midazolam group for complaint scores of palpitations (P = 0.04) and chest pain (P = 0.02) and a trend to reduction in complaint scores for most other parameters. There were no adverse outcomes in any of the patients studied.

CONCLUSIONS

Co-administration of midazolam can safely reduce the recall of the unpleasant adverse effects of adenosine. Its use may be most appropriate in patients who are particularly anxious or have had previous adverse experiences with adenosine.