A company developing cell therapies that do not require harvesting from individual patients presented data at the American Society of Hematology’s annual meeting in San Diego on a therapy for a condition that affects bone marrow and organ transplant patients.
Atara Biotherapeutics, based in South San Francisco, California, on Monday highlighted data from its Phase II study of its Epstein-Barr virus-specific T cells in patients with EBV post-transplant lymphoproliferative disorder, or PTLD, in the central nervous system that arises after hematopoietic stem cell transplant or solid organ transplant. The data were presented in a poster at the ASH conference, which concludes Tuesday.
What makes PTLD especially difficult to treat when it reaches the CNS is that one of the standard PTLD treatments, Roche’s Rituxan (rituximab), is unable to get through the blood-brain barrier, said Atara Chief Medical Officer Dietmar Berger in an interview in New York, ahead of the ASH conference. But T cells can. “We see the same activity in CNS PTLD as when it’s systemic,” he said.
The Food and Drug Administration approved the first biosimilar version of Rituximab, Celltrion and Teva Pharmaceutical Industries’ Truxima, last week, albeit with a much narrower label than the Roche product.
According to the abstract, patients received EBV-specific T cells, or EBV-CTLs, from primary hematopoietic transplant donors or from third-party donors, with the latter referred to as tabelecleucel, with 12 of 19 treated patients receiving the latter. Of the 19 patients, seven achieved complete responses, while five achieved durable partial responses, yielding a 63 percent overall response rate. The one-year overall survival rate among the patients overall was 60 percent, while among those responding it was 91.7 percent, despite CNS PTLD being a complication that is frequently lethal.
In addition to tabelecleucel, referred to as tab-cel for short, the company’s pipeline also includes several allogeneic CAR-T therapies for blood cancers, solid tumors, autoimmune diseases and infectious diseases, among other programs in preclinical and clinical development.
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