“This is the first time there is a real-world comparison of CAR-T cell therapy versus other treatments in the era of other novel therapies such as inotuzumab or tyrosine kinase inhibitors (TKIs),” said first author Alexandros Rampotas, MD, of the University College London Hospital NHS Foundation Trust. “The study was looking retrospectively at patients treated in the UK, but the results should be applicable to most countries where similar treatments are available.”
Dr. Rampotas presented the research at the 6th European CAR T-cell Meeting jointly sponsored by the Society for Blood and Marrow Transplantation and the European Hematology Association.
Outcomes when patients with B-ALL relapse after allo-HCT treatment are generally very poor, and while the advent of CAR T-cell therapy has provided significant improvements, additional novel targeted therapies have also joined the field to further improve outcomes.
With no prior studies directly comparing outcomes between the various treatment options in a real-world setting, Dr. Rampotas and colleagues conducted a retrospective analysis of posttransplant relapsed B-ALL cases at six major transplant centers in the United Kingdom between 2010 and 2022.
Of 93 patients with sufficient data for the analysis, 17 had been treated with CAR T-cell therapy: 4 with UCART19, 1 with CD22 CAR T-cell, and 12 with the CD19-directed CAR T-cell products tisagenlecleucel (Kymriah) or obecabtagene autoleucel (obe-cel).
Among the remaining 75 patients who received non-CAR T-cell therapies, 24 received TKIs, 11 received blinatumumab, 12 received inotuzumab, 10 received intensive chemotherapy, 3 received intensive chemotherapy and TKI therapy, 14 received palliative/supportive regimens and 1 had a second allo-HCT following relapse from the first.
The median time from relapse to treatment was 2.8 months in the CAR T-cell therapy group, and 0.32 months for those receiving non-CAR T-cell therapies.
“The 2.8-month time-to-treat is quite expected as CAR T-cells can take a while to manufacture and be infused,” Dr. Rampotas noted. “This also comes with the bias that the patients who did receive them were likely fitter and could wait for that long.”
Patients receiving CAR T-cell therapy were also younger (median age 26 versus 47 in the non-CAR T-cell group) but the CAR T-cell group had higher risk disease and had a median of 2 prior lines of therapy versus 1 in the non-CAR T-cell group.
With a median follow-up of 24.8 months, patients receiving CAR T-cell therapy had significantly better rates of overall survival (OS), with 31 months compared with the non-CAR T-cell therapy OS of just 6.4 months (P = .0147).
The patients treated with CAR T-cell therapy also had improved progression-free survival (PFS) over the non-CAR T-cell patients (16.7 vs 3.7 months; P = .0001).
The superior outcomes in the CAR T-cell group remained consistent after exclusion of patients who received palliative approaches.
“In the realm of numerous innovative therapies for B-ALL, CAR Ts have now, for the first time, exhibited superior outcomes over alternative approaches in posttransplant relapsed B-ALL in the real world,” the authors reported. “The clear superior PFS and OS should encourage the use of more CAR T-cell therapies for this challenging cohort, while further improvements are imperative to enhance outcomes.”
In the meantime, “patients who relapse post transplant with B-ALL should be referred for CAR-T cell therapy as it is a superior treatment to other available options,” Dr. Rampotas said.
Dr. Rampotas discloses receiving conference fees from Gilead.