Atara Biotherapeutics Reports Updated Long-Term Clinical Results from a Tab-cel® Multicenter Expanded Access Protocol (EAP) Study for Patients with Epstein-Barr Virus-Associated Post-Transplant Lymphoproliferative Disease (EBV+ PTLD) at the 61st American Society Of Hematology (ASH) Annual Meeting
61 patients with diverse EBV-associated diseases, including 26 relapsed/refractory EBV+ PTLD patients were treated in a multicenter tab-cel® (tabelecleucel) EAP study
Tab-cel® was generally well-tolerated in all patients with EBV+ PTLD and other EBV-associated diseases
Estimated two-year overall survival rate in tab-cel® responders was 86 and 100 percent for patients with EBV+ PTLD following HCT and SOT, respectively, with median time to response of one month
Similar outcomes observed in subgroup of 22 patients with EBV+ PTLD who would have likely met eligibility criteria for Atara’s ongoing tab-cel® Phase 3 studies
Results from this analysis demonstrate a high overall response rate (ORR), short time to response and favorable estimated long-term overall survival (OS) rates for tab-cel® in patients with EBV+ PTLD following hematopoietic cell transplant (HCT) or solid organ transplant (SOT) who have failed rituximab-based therapy. Tab-cel® was generally well-tolerated in all patients with EBV+ PTLD and other EBV-associated diseases.
“Patients undergoing allogeneic hematopoietic cell or solid organ transplants are at risk for developing EBV+ PTLD,” said
Twenty-six EBV+ PTLD patients who failed prior rituximab treatment regimens were enrolled in EAP-201 as of
In the EBV+ PTLD HCT and SOT cohorts, 92 and 63 percent of patients were intermediate/high risk according to the PTLD prognostic index1, respectively.
Safety analyses were presented for all patients treated with tab-cel® (n=61; n=26 EBV+ PTLD and n=35 patients with other EBV-associated diseases). Consistent with prior studies, tab-cel® was generally well-tolerated in all patients, and no tab-cel® related adverse events leading to discontinuation occurred.
The most common treatment-emergent serious adverse events (TESAEs) reported in ≥ 5 percent of all patients were disease progression (16 percent), pyrexia (8 percent) and pneumonia (7 percent).
Three graft versus host disease (GvHD) adverse events were reported, all in patients with prior allogeneic HCT. No other adverse events of special interest including cytokine release syndrome were reported.
Median time to response of one month was seen in both EBV+ PTLD patient cohorts. In responders, two-year estimated overall survival rate was 86 percent for HCT (n=7) and 100 percent for SOT (n=10) with no patient deaths attributable to PTLD progression.
Similar outcomes were observed in the EAP-201 subgroup of EBV+ PTLD patients (n=22) with adequate ECOG performance status, no CNS disease and no PLTD-related ventilatory support who would have likely met the eligibility criteria for Atara’s ongoing tab-cel® Phase 3 studies. Overall response rate was 55 and 82 percent, with a two-year estimated overall survival of 79 and 81 percent, in the HCT (n=11) and SOT (n=11) cohorts, respectively.
“We have previously shown that EBV+ PTLD patients treated with tab-cel® resulted in high overall response rates and favorable long-term survival,” said AJ Joshi, MD, Senior Vice President and Chief Medical Officer of
Efficacy for EBV+ PTLD HCT Cohort
|HCT cohort||All HCT (N=14)||Potential Ph3 subset2 (N=11)||Responders (N=7)|
|ORR (investigator-assessed), n (%)||7 (50)||6 (55)||-|
|1-year OS, % (95% CI)||60 (29, 81)||79 (38, 94)||86 (33, 98)|
|2-year OS, % (95% CI)||60 (29, 81)||79 (38, 94)||86 (33, 98)|
Efficacy for EBV+ PTLD SOT Cohort
|SOT cohort||All SOT (N=12)||Potential Ph3 subset2 (N=11)||Responders (N=10)|
|ORR (investigator-assessed), n (%)||10 (83)||9 (82)||-|
|1-year OS, % (95% CI)||83 (46, 95)||81 (42, 95)||100|
|2-year OS, % (95% CI)||83 (46, 95)||81 (42, 95)||100|
Abstract 4071: Long-Term Outcomes of Subjects with Epstein-Barr Virus-Driven Post-Transplant Lymphoproliferative Disorder (EBV+PTLD) Following Solid Organ (SOT) or Allogeneic Hematopoietic Cell Transplants (HCT) Treated with Tabelecleucel on an Expanded Access Program
Poster Presentation Date and Time:
Session Title: 626. Aggressive Lymphoma (Diffuse Large B-Cell and Other Aggressive B-Cell Non-Hodgkin Lymphoma) – Results from Prospective Clinical Trials: Poster III
Authors: Susan Prockop, M.D.1, Ran Reshef, M.D.2,
1Choquet S et al. Ann Hematol 2007; 86:599–607
2Based on adequate ECOG performance status, no CNS disease, and no PTLD-related ventilatory support
About Atara Biotherapeutics, Inc.
This press release contains or may imply "forward-looking statements" within the meaning of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934. For example, forward-looking statements include statements regarding: the potential effectiveness, impact and benefit-risk profile of tab-cel®; and the results from Atara’s ongoing tab-cel® EAP study. These forward-looking statements are subject to risks and uncertainties, including those discussed in
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