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EBV+ LMS is a rare cancer that develops in patients with immune deficiency. EBV+ LMS responds poorly to radiation and chemotherapy resulting in limited treatment options and poor outcomes.1 Tabelecleucel is an investigational, off-the-shelf, genetically unmodified, allogeneic T-cell immunotherapy targeting EBV antigens. Here we report the efficacy and safety of tabelecleucel in a subgroup of EBV+ LMS patients from 3 clinical trials.
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Tabelecleucel was evaluated in 2 single-center, open-label studies (NCT00002663 [Study 1], NCT01498484 [Study 2]) and a multi-center expanded access protocol (NCT02822495 [Study 3]). Tabelecleucel was given at 1.0–2.0 x 106 cells/kg/dose on days 1, 8, and 15 of every 4-6-week cycle, and imaging was performed before the 1st dose of each cycle.
A total of 12 patients with EBV+ LMS received ≥ 1 dose of tabelecleucel, 10 of whom were assessed for responses (1 patient was not evaluable and 1 patient was too early to assess). Using CT-based RECIST 1.1 criteria, 2 patients achieved a partial response (objective response rate = 17%) and 8 patients achieved stable disease. In studies 1 and 2 where longer follow-up is available, 6 of 8 patients survived ≥ 27 months. The median survival (95% CI) is 77.4 (18, NE) months. At the time of this analysis, metabolic responses were available in study 3: 3 of the 4 patients (75%) achieved a metabolic response. The safety profile is consistent with previously reported data;2 no new safety signals have been identified.
This analysis represents one of the larger prospective studies of patients with EBV+ LMS. The combination of CT-based and metabolic responses to tabelecleucel, in the context of prolonged survival, demonstrate that tabelecleucel (also known as tab-cel™) may provide clinical benefit in this typically radiation- and chemotherapy-resistant disease. Tabelecleucel is well tolerated in this population of patients. References: 1. Wang Z et al. Cancer Med. 2016;5(12):3437-3444. 2. Prockop SE et al. Blood. 2017;130:4520.
Editorial assistance in the writing of this abstract was provided by Kathryn Boorer, PhD of KB Scientific Communications, LLC.
NCT00002663, NCT01498484, NCT02822495.
Atara Biotherapeutics and Memorial Sloan Kettering Cancer Center.
Atara Biotherapeutics and Memorial Sloan Kettering Cancer Center.
S. Suser: Research funding: Atara Biotherapeutics. E. Doubrovina: Royalties following licensure of the EBV-specific T-cell bank: Atara Biotherapeutics; Research support and consultant fees: Atara Biotherapeutics. A. Sudhindra, Y. Wei, M. Hiremath, W. Navarro: Employee and stock holder: Atara Biotherapeutics. R. O\'Reilly: Royalties following licensure of the EBV-specific T-cell bank: Atara Biotherapeutics; Research support and consultant fees: Atara Biotherapeutics. S. Prockop: Research funding: Atara Biotherapeutics. All other authors have declared no conflicts of interest.