Phase 1 UCART22 Trial Shows Promising Activity in R/R B-Cell ALL: Nitin Jain, MD

Findings from the phase 1 BALLI-01 trial (NCT04150497) of UCART22, an allogeneic, off-the-shelf chimeric antigen receptor (CAR) T-cell therapy targeting CD22, showed promising activity in heavily pretreated patients with relapsed/refractory (R/R) B-cell acute lymphoblastic leukemia (ALL), according to data presented at the European Hematology Association 2026 Congress by principal investigator Nitin Jain, MD.

At the meeting, Jain explained to The American Journal of Managed Care^® that UCART22 was developed to address an unmet need in B-cell ALL. While CD19-directed CAR T-cell therapies have received regulatory approval, none currently exist for CD22, despite the antigen being broadly expressed in this population. He added that the allogeneic, premanufactured nature of UCART22 offers a practical advantage, as it is immediately available for patients with ALL, who often carry a high disease burden and cannot afford the weeks-long wait associated with autologous manufacturing.

Jain noted that the phase 1 study evaluated safety, established the recommended phase 2 dose (RP2D), and assessed efficacy outcomes, including overall response rate and survival. It also examined the role of alemtuzumab in the lymphodepletion regimen by tracking peak drug levels alongside CAR T-cell expansion.

A mid-trial manufacturing shift played a key role in the efficacy results. The first 20 patients received an externally manufactured product (process 1), which yielded lower-than-expected response rates. The researchers then switched to in-house manufacturing (process 2), producing cells with a more naive, active phenotype.

Among the 25 patients treated under process 2, approximately 36% achieved a complete remission (CR) or CR with incomplete count recovery, a higher rate than seen with process 1. Based on the overall efficacy and safety data, Jain noted that 5×10⁶ cells/kg was selected as the RP2D.

Jain also outlined the rationale for the pivotal phase 2 study's age cutoff of 50 years or younger. Because UCART22 is intended to bridge patients to subsequent allogeneic stem cell transplantation, and because durable remission without that consolidation step is unlikely, the team reasoned that younger patients are best positioned to benefit. In patients older than 50 to 60 years, the likelihood of proceeding to transplant decreases, making the benefit-to-risk profile less favorable.

"We felt that's the group of patients who can derive benefit from and then be able to go to a subsequent allogeneic transplant," Jain said.