BCR-ABL–specific T-cell therapy in Ph+ ALL patients on tyrosine-kinase inhibitors

Although the emergence of bone marrow (BM)–resident p190BCR-ABL–specific T lymphocytes has been correlated with hematologic and cytogenetic remissions in patients with Philadelphia chromosome–positive acute lymphoblastic leukemia (Ph+ ALL) undergoing maintenance tyrosine-kinase inhibitor treatment, little is known about the possibility of culturing these cells ex vivo and using them in T-cell therapy strategies. We investigated the feasibility of expanding/priming p190BCR-ABL–specific T cells in vitro by stimulation with dendritic cells pulsed with p190BCR-ABL peptides derived from the BCR-ABL junctional region and alternative splicing, and of adoptively administering them to patients with relapsed disease. We report on the feasibility of producing clinical-grade BCR-ABL–specific cytotoxic T lymphocytes (CTLs), endowed with antileukemia activity, from Ph+ ALL patients and healthy donors. We treated 3 patients with Ph+ ALL with autologous or allogeneic p190BCR-ABL–specific CTLs. No postinfusion toxicity was observed, except for a grade II skin graft-versus-host disease in the patient treated for hematologic relapse. All patients achieved a molecular or hematologic complete remission (CR) after T-cell therapy, upon emergence of p190BCR-ABL–specific T cells in the BM. Our results show that p190BCR-ABL–specific CTLs are capable of controlling treatment-refractory Ph+ ALL in vivo, and support the development of adoptive immunotherapeutic approaches with BCR-ABL CTLs in Ph+ ALL. •BCR-ABL–specific CTLs may be obtained by stimulation with peptides derived from BCR-ABL junctional region and alternative splicing.•T-cell therapy with BCR-ABL–specific CTLs from healthy donors or patients mediates molecular or hematologic CR in patients with Ph+ ALL.