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ASH Annual Meeting and Exposition
ByMatthew Shinkle
Fact checked byMindy Valcarcel, MS
December 20, 2024
2 min read
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Cell therapy benefits patients with EBV-driven post-transplant lymphoproliferative disease

ByMatthew Shinkle
Fact checked byMindy Valcarcel, MS

Key takeaways:

  • About half of patients with Epstein-Barr virus-associated post-transplant lymphoproliferative disease responded to tabelecleucel.
  • Half of responses lasted longer than 6 months.

SAN DIEGO — Tabelecleucel provided durable benefit to solid organ or allogeneic hematopoietic cell transplant recipients with Epstein-Barr virus-driven post-transplant lymphoproliferative disease, according to study results.

About half of patients responded and median OS exceeded 18 months, updated findings from the phase 3 ALLELE trial presented at ASH Annual Meeting and Exposition showed.

Graphic distinguishing meeting news
About half of patients treated with tabelecleucel responded to therapy, and median duration of response reached 23 months.

Background and methods

Tabelecleucel (Atara Biotherapeutics) is an off-the-shelf allogeneic Epstein-Barr virus (EBV)-specific cytotoxic T-cell therapy.

Researchers conducted the open-label ALLELE trial to assess the agent for patients with relapsed or refractory EBV-associated post-transplant lymphoproliferative disease (PLTD) that developed after solid organ transplant or HSCT.

All study participants had received rituximab (Rituxan; Genentech, Biogen) with or without chemotherapy.

Patients received tabelecleucel dosed at 2 x 106 cells/kg on days 1, 8 and 15 of each 35-day cycle.

Researchers assessed efficacy and safety for up to 5 years. Overall response rate, duration of response, time to response and OS served as key endpoints.

The study included 75 patients (median age, 44.4 years; range, 2.7-81.5), 49 of whom underwent solid organ transplant and 26 of whom underwent HSCT. Eleven patients (14.7%) were aged younger than 18 years.

One-quarter (24%) of those aged 16 years or older had an ECOG performance status of 2 or greater. Half (50%) had intermediate risk and 43.8% had high risk per the PTLD-adapted prognostic index.

Median time from transplant to diagnosis of EBV-associated PTLD was 0.9 years (range, 0.2-26.2) for patients who underwent solid organ transplant and 3.9 months (range, 0.6 66) for those who underwent HSCT.

Median time from EBV-associated PTLD diagnosis to first dose of tabelecleucel was 4.6 months (range, 0.6-190.5).

Patients received a median one prior therapy (range, 1-5). The majority had received rituximab monotherapy (86.7%), chemotherapy-containing regimens (46.7%) and/or rituximab plus chemotherapy (37.3%).

Results, next steps

Results showed ORRs of 50.7% (95% CI, 38.9-62.4) in the entire cohort, 51% (95% CI, 36.3-65.6) among patients who underwent solid organ transplant and 50% (95% CI, 29.9-70.1) among those who underwent HSCT.

Researchers reported a complete response rate per independent oncologic response adjudication of 28% (95%; CI, 18.2-39.6) and a partial response rate of 22.7% (95% CI, 13.8-33.8).

Median time to response was 1.1 months (range, 0.6-9) and median response duration was 23 months (12.1 to not estimable). More than half (52.6%; n = 20 of 38) of complete or partial responses lasted at least 6 months.

Results showed a clinical benefit rate of 60% in the entire cohort, 57.1% for patients who underwent solid organ transplant and 65.4% for those who underwent HSCT.

Median OS was 18.4 months (95% CI, 5.7 to not estimable) for the entire study population, 18.4 months (95% CI, 5 to not estimable) for those who underwent solid organ transplant and 18.6 months (95% CI, 2.9 to not estimable) for those who underwent HSCT.

Researchers reported 1-year OS rates of 55.7% in the entire study population, 57.1% for patients who underwent solid organ transplant and 52.4% for those who underwent HSCT.

Results showed a considerably higher 1-year OS rate among patients who responded to tabelecleucel than those who did not (78.7% vs. 28.2%).

Researchers reported comparable rates of serious treatment-emergent adverse events (65.4% vs. 61.2%) and fatal treatment-emergent adverse events (19.2% vs. 18.4%) among patients who had undergone HSCT vs. solid organ transplant.

Investigators reported no tumor flare reactions, infusion reactions, cytokine release syndrome, immune effector cell-associated neurotoxicity syndrome, marrow rejection or transmission of infectious diseases. No tabelecleucel-related graft vs host disease or organ rejection occurred.

Sources/Disclosures

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Source:

Ghobadi A, et al. Abstract 70. Presented at: ASH Annual Meeting and Exhibition; Dec. 7-10, 2024; San Diego.

Disclosures: Ghobadi reports financial disclosures with Amgen, Atara Biotherapeutics, Bristol Myers Squibb, CRISPR Therapeutics, Genentech, Kite Pharma and Wugen Inc. Please see the abstract for all other researchers’ relevant financial disclosures.