Three-Year Outcomes in Recipients of Mismatched Unrelated Bone Marrow Donor Transplants Using Post-Transplantation Cyclophosphamide: Follow-Up from a National Marrow Donor Program-Sponsored Prospective Clinical Trial.

The use of post-transplantation cyclophosphamide (PTCy) as graft-versus-host disease (GVHD) prophylaxis has resulted in reductions in GVHD and improved outcomes in allogeneic hematopoietic cell transplantation (HCT) using HLA-mismatched related donors. We report the 3-year outcomes of the first multicenter prospective clinical trial using PTCy in the setting of mismatched unrelated donor (MMUD) bone marrow HCT. The study enrolled 80 patients, treated with either myeloablative conditioning (MAC; n = 40) or reduced-intensity conditioning (RIC; n = 40), with the primary endpoint of 1-year overall survival (OS). The median follow-up for this study was 34 months (range, 12 to 46 months) in the RIC group and 36 months (range, 18 to 49 months) in the MAC group. Three-year OS and nonrelapse mortality were 70% and 15%, respectively, in the RIC group and 62% and 10% in the MAC group. No GVHD was reported after 1 year. The incidence of relapse was 29% in the RIC group and 51% in the MAC group. OS did not differ based on HLA match grade (63% in the 7/8 strata and 71% in the 4 to 6/8 strata). These encouraging outcomes, which were sustained for 3 years post-HCT, support the continued exploration of MMUD HCT using a PTCy platform. Important future areas to address include relapse reduction and furthering our understanding of optimal donor selection based on HLA and non-HLA factors.

Adding Centralized Electronic Patient-Reported Outcome Data Collection to an Established International Clinical Outcomes Registry.

The importance of patient-reported outcomes (PROs) in cellular therapies, including hematopoietic cell transplantation (HCT) is highlighted in this study. Longitudinal collection of PROs in a registry is recommended for several reasons, yet to date, PROs are not routinely collected from HCT patients to augment clinical registry data. The aim of this study was to determine the feasibility of electronic PRO data collection by a national clinical outcomes registry, by assessing differences between who does and does not report PROs. We conducted a cross-sectional pilot collection of PROs from HCT recipients after treatment using computer-adapted tests from the Patient-Reported Outcome Measurement Information System (PROMIS). We implemented centralized data collection through the Center for International Blood and Marrow Transplant Research (CIBMTR) among patients who underwent HCT for myelodysplastic syndromes (MDS), were at least 6 months post-HCT, and spoke English or Spanish. The main objective was identifying patient, disease, and transplant-related differences associated with completion of electronic PROs. Patients were excluded from analysis if they were determined to be ineligible (deceased, did not speak English or Spanish, refused to be contacted by the CIBMTR). A total of 163 patients were contacted and potentially eligible to participate; of these, 92 (56%) enrolled and 89 (55%) completed the PRO assessment. The most frequent reason for incomplete surveys was inability to contact patients (n = 88), followed by declining to participate in the study (n = 37). There were no sociodemographic or age differences between those who completed the PRO survey (n = 89) and eligible nonresponders (n = 155). Patient scores were within 3 points of the US average of 50 for all symptoms and functioning except physical functioning. Responders and nonresponders did not exhibit meaningfully different sociodemographic characteristics. Difficulty contacting patients posed the greatest barrier and also provided the greatest opportunity for improvement. Once enrolled, survey completion was high. These results support standardizing centralized PRO data collection through the CIBMTR registry.

National Marrow Donor Program-Sponsored Multicenter, Phase II Trial of HLA-Mismatched Unrelated Donor Bone Marrow Transplantation Using Post-Transplant Cyclophosphamide.

PURPOSE: Hematopoietic cell transplantation (HCT) is curative for hematologic disorders, but outcomes are historically inferior when using HLA-mismatched donors. Despite unrelated donor registries listing > 38 million volunteers, 25%-80% of US patients lack an HLA-matched unrelated donor, with significant disparity across ethnic groups. We hypothesized that HCT with a mismatched unrelated donor (MMUD) using post-transplant cyclophosphamide (PTCy), a novel strategy successful in overcoming genetic disparity using mismatched related donors, would be feasible and increase access to HCT. PATIENTS AND METHODS: We performed a prospective phase II study of MMUD bone marrow HCT with PTCy for patients with hematologic malignancies. The primary end point was 1-year overall survival (OS), hypothesized to be 65% or better. 80 patients enrolled at 11 US transplant centers (December 2016-March 2019). Following myeloablative or reduced-intensity conditioning-based HCT, patients received PTCy on days +3, +4, with sirolimus and mycophenolate mofetil starting on day +5. We compared outcomes to Center for International Blood and Marrow Transplant Research contemporary controls receiving PTCy. RESULTS: Notably, 48% of patients enrolled were ethnic minorities. 39% of pairs were matched for 4-6 out of 8 HLA alleles. The primary end point was met, with 1-year OS of 76% (90% CI, 67.3 to 83.3) in the entire cohort, and 72% and 79% in the myeloablative and reduced-intensity conditioning strata, respectively. Secondary end points related to engraftment and graft-versus-host-disease were reached. Multivariate analysis comparing the study group with other mismatched HCT controls found no significant differences in OS. CONCLUSION: Our prospective study demonstrates the feasibility and effectiveness of HCT with an MMUD in the setting of PTCy. Remarkably, nearly half of the study participants belonged to an ethnic minority population, suggesting this approach may significantly expand access to HCT.