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4905 Comparison of Non-Relapse Mortality after Haploidentical Hematopoietic Stem Cell Transplantation with Post-Transplant Cyclophosphamide Versus Single Umbilical Cord Blood Transplantation for Hematologic Disease

Program: Oral and Poster Abstracts
Session: 721. Allogeneic Transplantation: Conditioning Regimens, Engraftment and Acute Toxicities: Poster III
Hematology Disease Topics & Pathways:
Research, Clinical Research, health outcomes research
Monday, December 11, 2023, 6:00 PM-8:00 PM

Kaito Harada, MD, PhD1*, Junya Kanda, MD, PhD2*, Masahiro Hirayama, M.D., Ph.D.3*, Fumiya Wada, MD4*, Naoyuki Uchida, MD, PhD5, Hirohisa Nakamae, MD, PhD6*, Masatsugu Tanaka, M.D., Ph.D.7*, Makoto Onizuka, MD, PhD8, Hiroyuki Ohigashi, MD, PhD9*, Nobuaki Nakano, M.D.10*, Takahiro Fukuda, MD, PhD11*, Kazuya Ishiwata, M.D., Ph.D.12*, Yumiko Maruyama, MD, PhD13*, Tetsuya Eto, MD, PhD14*, Fumihiko Ishimaru, MD, PhD15, Yoshiko Atsuta, MD, PhD16*, Hideki Nakasone, MD, PhD17 and Takashi Tanaka, MD11*

1Department of Hematology and Oncology, Tokai University School of Medicine, Kanagawa, Japan
2Department of Hematology / Oncology, Kyoto University Graduate School of Medicine, Kyoto, Japan
3Department of Pediatrics, Mie University Graduate School of Medicine, Tsu, JPN
4Department of hematology and Oncology, Graduate school of Medicine, Kyoto University, Kyoto, KYO, JPN
5Department of Hematology, Toranomon Hospital, Tokyo, Japan
6Department of Hematology, Osaka Metropolitan University Hospital, Osaka, Japan
7Department of Hematology, Kanagawa Cancer Center, Kanagawa, Japan
8Department of Hematology/Oncology, Tokai University School of Medicine, Isehara, Japan
9Department of Hematology, Hokkaido University Faculty of Medicine and Graduate School of Medicine, Sapporo, Japan
10Department of Hematology, Imamura General Hospital, Kagoshima, Japan
11Department of Hematopoietic Stem Cell Transplantation, National Cancer Center Hospital, Tokyo, Japan
12Department of Hematology, Toranomon Hospital Kajigaya, Kanagawa, Japan
13Department of Hematology, University of Tsukuba Hospital, Tsukuba, JPN
14Department of Hematology, Hamanomachi Hospital, Fukuoka, JPN
15Japanese Red Cross Kanto-Koshinetsu Block Blood Center, Tokyo, Japan
16Japanese Data Center For Hematopoietic Cell Transplantation, Nagakute, Japan
17Division of Hematology, Jichi Medical University Saitama Medical Center, Saitama, Japan

Introduction: Unrelated cord blood transplantation (UCBT) and haploidentical stem cell transplantation with post-transplant cyclophosphamide as graft-versus-host disease (GVHD) prophylaxis (PTCy-haplo) are alternative options for patients with hematologic disease lacking a human leukocyte antigen (HLA)-matched donor. Non-relapse mortality (NRM) after UCBT may vary depending on the cord blood CD34+ cell count, but no study has accounted for CD34+ cell count when comparing the outcomes after UCBT and PTCy-haplo. Therefore, we analyzed transplant outcomes after UCBT and PTCy-haplo in patients with hematologic disease from data of a nationwide registry that included cord blood CD34+ cell count.

Methods: Patients with hematologic disease receiving first UCBT or PTCy-haplo between 2014 and 2020 were identified from the nationwide registration data of the Japanese Data for Hematopoietic Cell Transplantation. Acute GVHD-related mortality was defined as death caused primarily by GVHD or occurred secondary to GVHD, and infection-related mortality as death due to graft failure or infection but not acute GVHD. Patients treated by UCBT were stratified by the median CD34+ cell count for comparison (0.84 × 105/kg).

Results: A total of 7,499 patients were enrolled and classified into 3 groups: PTCy-haplo (n = 1,142), UCBT with high CD34+ cell count (UCB-H; ≥ 0.84 × 105/kg, n = 3,185), and UCBT with low CD34+ cell count (UCB-L; < 0.84 × 105/kg, n = 3,172). Patients in the PTCy-haplo group were slightly younger than UCB-H and UCB-L patients (median age: 54 vs. 56 and 55 years). The PTCy-haplo group also included a greater proportion of males than the UCB-H group (62.4% vs. 50.0%) but not the UCB-L group (64.2%). A greater proportion of PTCy-haplo patients had a PS score of 0 (53.2% vs. 46.2% and 45.6%), a hematopoietic cell transplantation-specific comorbidity index of 0 (57.6% vs. 52.7% and 54.4%) and donor-specific anti-HLA antibody (2.7% vs. 1.0% and 1.6%), received reduced-intensity conditioning (58.0% vs. 40.5% and 41.6%), calcineurin inhibitor with mycophenolate mofetil (88.5% vs. 38.6% and 38.4%), and underwent transplantation in the later period (82.0% vs. 54.6% and 50.7%). There were no significant differences in disease-risk index between groups. At 2 years post-transplantation, NRM and overall survival (OS) were significantly better in the PTCy-haplo group than the UCB-H and UCB-L groups (NRM: 18.8% vs. 21.6% and 25.3%, P < 0.001; OS: 56.2% vs. 53.3% vs. 49.6%, P < 0.001). Neutrophil engraftment rate at 42 days was also significantly higher in the PTCy-haplo group than the UCB-H and UCB-L groups (93.7% vs. 87.5% and 82.9%, P < 0.001). The PTCy-haplo group less frequently developed grade II–IV (26.4% vs. 37.3% and 34.4%, P < 0.001) and III–IV acute GVHD (7.0% vs. 12.2% and 10.5%, P < 0.001). While neither the differences in NRM nor that in OS remained significant between PTCy-haplo and UCB-H groups in multivariable analysis (NRM: hazard ratio [HR], 1.18, 95% confidence interval [CI], 0.99–1.41, P = 0.073; OS: HR, 1.05, 95% CI, 0.94–1.17, P = 0.42), significant differences were maintained between PTCy-haplo and UCB-L groups (NRM: HR, 1.35, 95% CI, 1.13–1.61, P = 0.001; OS: HR, 1.12, 95% CI, 1.00–1.26, P = 0.042). Regarding the cause-specific mortality, infection-related mortality was also significantly lower in the PTCy-haplo group compared to UCB-H and UCB-L groups (8.1% vs. 11.1% and 13.6%, P < 0.001) while GVHD-related mortality did not differ among groups (5.0% vs. 5.2% and 4.9%, P = 0.69).

Conclusion: UCBT-H resulted in similar NRM and OS as patients receiving PTCy-haplo, whereas outcomes were worse in UCBT-L. These findings indicate that high CD34+ cell count in cord blood is a critical criterion for alternative donor selection.

Disclosures: Harada: Nippon Shinyaku: Research Funding. Kanda: Amgen: Ended employment in the past 24 months, Honoraria; Janssen Pharmaceutical K.K.: Honoraria; Novartis Pharma K.K.: Honoraria; Sanofi K.K.: Honoraria; AbbVie Pharma: Honoraria; Megakaryon Co.: Honoraria; Eisai Co.: Research Funding. Nakamae: CMIC Company: Research Funding; Parexel International Inc: Research Funding; Takeda Pharmaceutical Company: Honoraria; Novartis: Research Funding; Alexion Pharma: Research Funding; Meiji Seika Pharma: Research Funding; DAIICHI SANKYO COMPANY: Honoraria; Janssen Pharmaceutical K.K.: Honoraria; Nihon Shinyaku: Honoraria; Sumitomo Dainippon Pharma: Honoraria; Bristol-Myers Squibb: Research Funding; Amgen: Honoraria; Otsuka: Honoraria; Abbvie: Honoraria; Astellas: Honoraria. Tanaka: Abbvie: Speakers Bureau; Asahi Kasei Pharma: Speakers Bureau; Astellas Phrama: Speakers Bureau; Chugai Pharmaceutical: Speakers Bureau; Daiichi Sankyo: Speakers Bureau; Kyowa-Kirin: Speakers Bureau; MSD: Speakers Bureau; Otsuka Pharmaceutical: Speakers Bureau; Pfizer: Speakers Bureau; Sumitomo Pharma: Speakers Bureau. Atsuta: Otsuka Pharmaceutical Co., Ltd: Speakers Bureau; Novartis Pharma KK: Speakers Bureau; CHUGAI PHARMACEUTICAL CO., LTD.: Speakers Bureau; Meiji Seika Pharma Co, Ltd.: Honoraria; JCR Pharmaceuticals Co., Ltd.: Consultancy. Nakasone: Otsuka Pharmaceutical: Honoraria; Bristol-Myers Squibb: Honoraria; Pfizer: Honoraria; Novartis: Honoraria; Takeda Pharmaceutical: Honoraria; Eisai: Honoraria; Chugai Pharmaceutical: Honoraria; Sanofi: Honoraria; Meiji Seika Pharma: Honoraria; Nippon Shinyaku: Honoraria.

*signifies non-member of ASH