Trial Outcomes & Findings for Optimizing Haploidentical Aplastic Anemia Transplantation (BMT CTN 1502) (NCT NCT02918292)

Participants were recruited from 14 centers between May 2017 and August 2020. The study opened to accrual on May 19, 2017 with 26 centers activated for enrollment. The study closed to accrual on August 31, 2020 and study completed on August 17, 2021. The study was initially designed to enroll participants into Unrelated Cord Blood and Haploidentical cohorts. Due to lack of accrual, the Unrelated Cord Blood cohort was closed for accrual per DSMB recommendation with no patients enrolled.

Serum Creatinine level is only measured for Participants \>= 13.0 years old at the time of enrollment.

Overall survival (OS) is the primary endpoint of this study. The time to this event is the time from transplant to death from any cause or last follow-up or 1 year from transplant, whichever occurs first. The one-year OS probability and its 95% confidence interval were estimated using the Kaplan-Meier estimator and Greenwood's formula.

Neutrophil recovery is achieving an absolute neutrophil count (ANC) \> 0.5 x10\^9/L for three consecutive measurements on different days, with the first of the three days being defined as the day of neutrophil engraftment. The cumulative percentage of neutrophil engraftment was estimated with a 95% confidence interval using the Aalen-Johansen estimator with death prior to neutrophil engraftment treated as a competing risk.

Platelet recovery is defined by achieving a platelet count \> 20 x 10\^9/L with no platelet transfusions in the preceding seven days. The first day of the sustained platelet count will be defined as the day of platelet engraftment. The cumulative percentage of platelet engraftment was estimated with a 95% confidence interval using the Aalen-Johansen estimator with death prior to platelet engraftment treated as a competing risk.

Being alive and engrafted is defined as not having experienced death, primary graft failure, or secondary graft failure. Donor cell engraftment is defined as donor chimerism greater than or equal to 5% on or after Day 56 after transplantation. Chimerism may be evaluated in whole blood or blood cell fractions, including CD3 and CD33 or CD15 fractions. For this protocol, lineage-specific, myeloid, and T cell chimerisms are required. This endpoint was adjudicated by the Endpoint Review Committee (ERC) and ERC data was used for the analysis.

Events for Graft-Failure-Free Survival (GFFS) including death, primary graft failure, secondary graft failure. The time to this event is the time from transplant to death from any cause, or graft failure, or last follow-up, or 1 year from transplant, whichever occurs first. For patients experiencing primary graft failure, Day 0.1 was used for primary graft failure event date to count the event in. The one-year GFFS probability and its 95% confidence interval were estimated using the Kaplan-Meier estimator and Greenwood's formula.

Primary graft failure is defined by the lack of neutrophil engraftment by Day 56 post-HSCT or failure to achieve at least 5% donor chimerism (whole blood or marrow) on any measurements up to and including Day +56. For this protocol, lineage-specific, myeloid, and T cell chimerisms are required. Myeloid engraftment might not proceed at the same rate as T cell engraftment. If myeloid has greater than or equal to 5% donor, even if T cell compartment does not, this is not considered primary graft failure. Secondary graft failure is defined by initial neutrophil engraftment (ANC greater than or equal to 0.5 x 10\^8/L measured for 3 consecutive measurements on different days) followed by sustained subsequent decline in ANC to less than 0.5 x 10\^9/L for three consecutive measurements on different days or initial whole blood or marrow donor chimerism greater than or equal to 5%, but then declining to less than 5% on subsequent measurements or second infusion/transplant given for graft failure.

Secondary graft failure is defined as any one of the following: 1. Initial neutrophil engraftment (ANC greater than or equal to 0.5 x10\^9/L measured for three consecutive measurements on different days) followed by sustained subsequent decline in ANC to less than 0.5 x 10\^9/L for three consecutive measurements on different days; 2. Initial whole blood or marrow donor chimerism greater than or equal to 5%, but then declining to less than 5% on subsequent measurements; 3. Second infusion/transplant given after Day 56 for graft failure.

Autologous recovery is defined as ANC \> 0.5 x 10\^9/L and transfusion independence but with \< 5% donor chimerism (whole blood or m. arrow). This endpoint was reviewed and adjudicated by ERC. The analysis is based on ERC data.

Acute GVHD is graded by consensus grading (Przepiorka 1995) per BMTCTN manual of procedures (MOP). Acute GVHD is graded by consensus grading (Przepiorka 1995) per BMTCTN manual of procedures (MOP). The time of onset of grades II-IV and grades III-IV acute GVHD were recorded. This endpoint is evaluated through 100 days post-transplant. Cumulative percentage of acute GVHD post-transplant are estimated using the cumulative incidence function, treating death prior to acute GVHD as the competing risk.

Acute GVHD is graded by consensus grading (Przepiorka 1995) per BMTCTN manual of procedures (MOP). Acute GVHD grading is performed by the consensus conference criteria (Przepiorka et al. 1995) with higher grade indicating worse outcomes. Grade I acute GVHD is defined as Skin stage of 1-2 and stage 0 for both GI and liver organs. Grade II is stage 3 of skin, or stage 1 of GI, or stage 1 of liver. Grade III is stage 2-4 for GI, or stage 2-3 of liver. Grade IV is stage 4 of skin, or stage 4 of liver. Maximum grade of acute GVHD through 100 days post transplant is reported.

The event for this secondary endpoint is any chronic GVHD based on 2014 NIH Consensus Criteria. This includes mild, moderate and severe chronic GVHD. The analyses of Chronic GVHD use the site-reported data. The cumulative percentage of chronic GVHD is computed using the cumulative incidence function, treating death prior to chronic GVHD as a competing risk. Eight organs will be scored on a 0-3 scale to reflect degree of chronic GVHD involvement. Liver and pulmonary function test results and use of systemic therapy for treatment of chronic GVHD will also be recorded. This secondary endpoint of chronic GVHD will include mild, moderate and severe chronic GVHD based on NIH Consensus Criteria.

The event for this secondary endpoint is any chronic GVHD based on 2014 NIH Consensus Criteria. Eight organs will be scored on a 0-3 scale to reflect degree of chronic GVHD involvement. Liver and pulmonary function test results and use of systemic therapy for treatment of chronic GVHD will also be recorded. The overall chronic GVHD severity is based on the eight organs score. The maximin severity level of chronic GVHD include mild, moderate and severe.

Quantitative assessments of peripheral blood CD3, CD4, CD8, CD19, and CD56 positive lymphocytes will be done through flow cytometric analysis.

Quantitative immunoglobulins of IgA, IgG, IgM were done at baseline and 1-year post-transplant.

Number of participants who reported the Maximum Infection Severity of Grade 2 and Grade 3. Only grade 2 and grade 3 infections occurring post transplantation were reported on the study. Grade 2 and grade 3 infections are defined by the BMT CTN Technical MOP. Higher infection grade indicates worse infection severity. The infection grading criteria are published online (https://bmtctn.net/administrative-manual-procedures-moppolicy-guidelines). Severity of grade 1, 2 and 3 are described for bacterial, fungal, viral, parasitic, and nonmicrobiological infections. For example, grade 2 fungal infections are defined as candida esophagitis, or proven or probably fungal sinusistis confirmed radiologically without orbital, brain or bone involvement. Grade 3 fungal infections are defined as Fungemia including candidemia, Proven or probably invasive fungal infections, Disseminated infections with histoplasmosis, blastomycosis, coccidiomycosis, or Cryptococcus, or Pneumocystis jiroveci pneumonia.

The number of systemic infections is reported. Infections are categorized by infection type. A participant can report multiple types of infections, so the categories are not mutually exclusive for participants. All grade 2 and grade 3 infections, as defined by the BMT CTN Technical MOP, occurring post transplantation were reported on the study.

CMV viremia and disease, EBV viremia, and PTLD are monitored and reported per protocol. The cumulative percentage of each outcome was estimated with a 95% confidence interval using the Aalen-Johansen estimator with death prior to event treated as a competing risk.

Toxicities are evaluated for the study participants at Day 28, Day 56, Day 100, Day 180 and Day 365 post-transplant and graded using NCI Common Terminology Criteria for Adverse Events (CTCAE) version 4.0. Grade 3-5 toxicities are reported with higher grade indicating worse outcomes. Toxicities are summarized here by system organ class (SOC). A participant can report multiple toxicities, so the categories are not mutually exclusive for participants.

HR-QoL will be measured using patient reported surveys at baseline and then at Day 100, Day 180, and Day 365 post-transplant. The MOS SF-36 is used for adult participants (\> 18 years). MOS SF-36 is a 36-item general assessment of HR-QoL with eight components: Physical Functioning, Role Physical, Pain Index, General Health Perceptions, Vitality, Social Functioning, Role Emotional, and Mental Health Index. Each domain is positively scored with higher scores associated with positive outcome. The scale is 0 to 100 where 0 is maximum disability and 100 is no disability. The Physical Component Summary (PCS) and Mental Component Summary (MCS) were used as the outcome measures in summarizing the SF-36 data for this study. These two summaries have the same score scale and Interpretation.

HR-QoL will be measured using patient reported surveys at baseline and then at Day 100, Day 180, and Day 365 post-transplant. The PedsQL Stem Cell Transplant Module for pediatric participants (8 years through 18 years). The PedsQL Stem Cell Transplant Module is a 46-item instrument that measures HR-QoL in children and adolescents undergoing hematopoietic stem cell transplant, and is developmentally appropriate for self-report in ages 8 through 18 years. The score ranges from 0 to 100 with higher scores associated with positive outcome.