6535 Background: For adults with ND Ph- B-ALL, frontline regimens now often include the CD19/CD3 bispecific blinatumomab (blin). However, blin administration is challenging, particularly for less-experienced centers. DA-EPOCH ± R is safe and active in these patients (pts; Cassaday, et al, Leuk Lymphoma , 2023) and easier to deliver. Tafa is a CD19 monoclonal antibody active in B-cell lymphomas. We hypothesized that the addition of tafa to DA-EPOCH ± R will yield higher rates of measurable residual disease negativity (MRD-) without increasing toxicity or administration complexity. Methods: This is a phase II investigator-initiated study (NCT05453500) in adults (>18 years) with ND CD19+ Ph- B-ALL not eligible for a pediatric regimen. DA-EPOCH ± R was given as cited above; tafa 12 mg/kg was given IV on day (d) 1, 8, and 15 of each cycle (C). After blin consolidation was FDA approved, pts could receive this off-study. The primary endpoint was MRD- by multiparameter flow cytometry (MFC) per EuroFlow (~2 pts: infection (9); febrile neutropenia (8); low fibrinogen (6); hypotension (5); and syncope (4). Initial CSF MFC was positive in 3 pts; HTS was positive in these plus 4 more (7 total). With a median f/u among survivors of 10 mo (1-37), there were 3 relapses: 1 post-HCT and 1 after only 2 treatment cycles; all were CD19+, and 0 involved CNS. Only 2 pts got blin consolidation. 6 pts died: 4 non-relapse causes (3 post-HCT) and 2 from refractory ALL. No deaths were due to study treatment. 1-year RFS and OS were estimated to be 67% and 76%, respectively. Conclusions: DA-EPOCH ± R + tafa yields high rates of MRD-. Follow-up is immature, but early survival rates are comparable to more complex strategies. This study is on pace to reach its primary endpoint, with enrollment ending before the conference. HTS on CSF can identify CNS disease more frequently. Clinical trial information: NCT05453500 .
Kopmar et al. (Wed,) studied this question.