Atara Biotherapeutics has secured approval from the US Food and Drug Administration (FDA) to begin two Phase lll clinical trials of tabelecleucel to treat patients with rituximab-refractory Epstein-Barr virus (EBV) associated post-transplant lymphoproliferative disorder (EBV+PTLD).

One of the new global, multicentre, open-label studies will include patients with EBV+PTLD following allogeneic hematopoietic cell transplant (HCT) after the failure of rituximab (MATCH).

The other study will be carried out to treat patients with EBV+PTLD following solid organ transplant (SOT) after the failure of rituximab or rituximab plus chemotherapy (ALLELE).

Both studies are expected to be immediately opened for enrolment in the US and will later be expanded to include sites in the EU, Canada, and Australia.

Atara aims to publish results from the first tabelecleucel study in the first half of 2019.

“Both protocols from the study are designed to discard 20% ORR as the null hypothesis.”

During the first half of 2019, the company also plans to submit a tabelecleucel conditional marketing authorisation (CMA) application in the EU for patients with rituximab-refractory EBV+PTLD following HCT.

Atara further plans to continue working with the FDA, Health Canada and other global health authorities to make tabelecleucel available to patients as early as possible.

The primary endpoint for both trials is to achieve the confirmed objective response rate (ORR), defined as the percent of patients achieving either a complete or partial response to tabelecleucel treatment confirmed after the initial tumour assessment showing a response.

Both protocols from the study are designed to discard 20% ORR as the null hypothesis.

Secondary endpoints of the MATCH and ALLELE studies will comprise the duration of response, overall survival, safety, quality of life metrics, as well as other data in support of potential health economic benefits.