61st American Society of Hematology (ASH) Annual Meeting
Atara Biotherapeutics, Inc. (Nasdaq: ATRA) will present long-term tab-cel® (tabelecleucel) clinical outcomes from a multicenter Expanded Access Protocol (EAP) study for patients with Epstein-Barr virus-associated post-transplant lymphoproliferative disease (EBV+ PTLD). These results, along with findings described in three additional abstracts, will be presented.
Twenty-six EBV+ PTLD patients who failed prior rituximab treatment regimens were enrolled in a tab cel® EAP study (EAP-201) as of June 2018, after which EAP-201 was amended to focus on expanded access for patients with EBV+ PTLD and other EBV+ diseases who are not eligible for Atara’s ongoing tab cel® Phase 3 studies (EAP-901, NCT02822495). The findings presented here are as of June 3, 2019. Consistent with prior studies, no tab-cel® related adverse events leading to discontinuation or death occurred.
A subgroup of 22 EAP-201 EBV+ PTLD patients with adequate ECOG performance status, no CNS disease and no PTLD-related ventilatory support, would have likely met the eligibility criteria for Atara’s ongoing tab cel® Phase 3 studies.
The overall response rate (ORR) for patients in this EAP-201 subgroup with EBV+ PTLD following HCT (n=11) and SOT (n=11) was 55 and 82 percent with an estimated two-year overall survival of 79 and 81 percent, respectively.
For all EBV+ PTLD patients enrolled in EAP-201, the ORR was 50 and 83 percent for HCT (n=14) and SOT (n=12), respectively.
Atara will also present additional findings describing the hospitalization burden of patients with EBV+ PTLD following SOT who failed first-line rituximab or rituximab plus chemotherapy.
In addition, Atara’s Moffitt Cancer Center collaborators will present two abstracts detailing next-generation CAR T technologies, licensed exclusively to Atara, and designed to enhance persistence while reducing susceptibility to exhaustion and suppressive immune microenvironments.