Atara Submits BLA for Cell Therapy for Post-Transplant Complication

Atara Biotherapeutics has submitted a biologics license application (BLA) to the FDA for tabelecleucel (tab-cel) as a monotherapy to treat adult and pediatric patients two years of age and older with Epstein-Barr virus positive post-transplant lymphoproliferative disease (EBV+ PTLD)

Lymphoproliferative disease is a rare but life-threatening complication after organ or stem-cell transplants. Many cases are associated with Epstein-Barr virus, accounting for more than 75% of post-transplant lymphoproliferative disease, according to one estimate.

Most people have been infected with Epstein-Barr at some point in their lives. The immune suppression used after a transplant can reactive the virus, causing B cells to grow uncontrollably.

There is no treatment available for specifically for Epstein-Barr virus related post-transplant lymphoproliferative disease, but Rituxan (rituximab) and chemotherapy are often used to treat the disease.

Tab-cel is an allogeneic, T-cell immunotherapy designed to target and eliminate cells infected with Epstein-Barr virus. If approved, it would be indicated for those patients who been treated with at least one other therapy.

The BLA is supported by pivotal and supportive data from more than 430 patients treated with tab-cel across multiple life-threatening diseases, including the pivotal ALLELE study. Interim data from this study found that 22 of 43 (51.2%) Epstein-Barr virus related post-transplant lymphoproliferative disease patients achieved an objective response rate (ORR).

Those who responded to tab-cel had longer survival, with an estimated one-year overall survival of 84.4% for responders versus 34.8% for non-responders. The median duration of response was 23.0 months and the median overall survival was 18.4 months.

Tab-cel was well tolerated with no reports of tumor flare reaction, cytokine release syndrome or immune effector cell-associated neurotoxicity syndrome, and no events of graft-versus-host disease or SOT rejection as related to tab-cel. These data were published in The Lancet Oncology in January 2024 and presented at the 2022 American Society of Hematology (ASH) Annual Meeting.

An Updated analysis from the October 2023 data showed tab-cel achieved a 49% objective response rate. ln addition, real-world results from the multicenter expanded access program study in Europe demonstrated an objective response rate of 66.7% in 24 patients and were presented at the 2023 American Society of Clinical Oncology (ASCO) Annual Meeting.

Tab-cel is approved under the brand name Ebvallo in the European Union, the United Kingdom and Switzerland. It is marketed by Pierre Fabre Laboraraties in these markets.

In December 2023, Atara Biotherapeutics expanded its previous partnership with Pierre Fabre to include the United States. Atara received $27 million cash up front. If the FDA accepts the BLA for tab-cel, that will trigger a milestone payment to Atara of $20 million with a potential additional $60 million if approved.