CD19-targeted chimeric antigen receptor (CAR) T cell therapy has become a breakthrough treatment for patients with relapsed/refractory B acute lymphoblastic leukemia (B-ALL). However, despite the high initial response rate, the majority of adult patients with B-ALL progress after CD19 CAR T therapy. Data on the natural history, management, and outcome of adult B-ALL progressing after CD19 CAR T cells have not been described in detail. Herein, we report comprehensive data of 38 adult B-ALL patients who progressed after CD19 CAR T therapy at our institution. The median time to progression after CAR T therapy was 5.5 months. Median survival after post-CAR T progression was 7.4 months. A high disease burden at the time of CAR T cell infusion was significantly associated with risk of post-CAR T progression. Thirty patients (79%) received salvage treatment for post-CAR T disease progression and 13 patients (43%) achieved complete remission (CR), but remission duration was short. Notably, 7 of 12 patients (58.3%) achieved CR after blinatumomab and/or inotuzumab administered after post-CAR T failure. Multivariate analysis demonstrated longer remission duration from CAR T cells was associated with superior survival after progression following CAR T therapy. In conclusion, overall prognosis of adult B-ALL patients progressing after CD19 CAR T cells was poor though a subset of patients achieved sustained remissions to salvage treatments including blinatumomab, inotuzumab and re-infusion of CAR T cells. Novel therapeutic strategies are needed to reduce risk of progression after CAR T therapy and improve outcomes of these patients.
Kitsada Wudhikarn, Jessica R Flynn, Isabelle Rivière, Mithat Gonen, Xiuyan Wang, Brigitte Senechal, Kevin J Curran, Mikhail Roshal, Peter G Maslak, Mark Blaine Geyer, Elizabeth F Halton, Claudia Diamonte, Marco L Davila, Michel Sadelain, Renier J Brentjens, Jae Park