Safety and tolerability of conditioning chemotherapy followed by CD19-targeted CAR T cells for relapsed/refractory CLL.

BACKGROUND: Subgroups of patients with relapsed or refractory (R/R) chronic lymphocytic leukemia (CLL) exhibit suboptimal outcomes after standard therapies, including oral kinase inhibitors. We and others have previously reported on safety and efficacy of autologous CD19-targeted CAR T-cells for these patients; here we report safety and long-term follow-up of CAR T-cell therapy with or without conditioning chemotherapy for patients with R/R CLL and indolent B-cell non-Hodgkin lymphoma (B-NHL). METHODS: We conducted a phase 1 clinical trial investigating CD19-targeted CAR T-cells incorporating a CD28 costimulatory domain (19-28z). Seventeen of 20 patients received conditioning chemotherapy prior to CAR T-cell infusion. Five patients with CLL received ibrutinib at the time of autologous T-cell collection and/or CAR T-cell administration. RESULTS: This analysis included 16 patients with R/R CLL and 4 patients with R/R indolent B-NHL. Cytokine release syndrome (CRS) was observed in all 20 patients but grades 3 and 4 CRS and neurological events were uncommon (10% for each). Ex vivo expansion of T-cells and proportions of CD4+/CD8+ CAR T-cells with CD62L+CD127+ immunophenotype were significantly greater in patients on ibrutinib at leukapheresis. Three of 12 evaluable CLL patients receiving conditioning chemotherapy achieved CR (two had minimal residual disease-negative CR). All patients achieving CR remained progression-free at median follow-up of 53 months. CONCLUSION: Conditioning chemotherapy and 19-28z CAR T-cells were acceptably tolerated across investigated dose levels in heavily pretreated patients with R/R CLL and indolent B-NHL, and a subgroup of patients achieved durable CR. Ibrutinib therapy may modulate autologous T-cell phenotype. TRIAL REGISTRATION: ClinicalTrials.gov NCT00466531. FUNDING: Juno Therapeutics.

Gene therapy for homozygous beta-thalassemia. Is it a reality?

The beta-thalassemias are genetic disorders that are caused by the absent or insufficient production of the beta-chain of hemoglobin. This deficiency causes ineffective erythropoiesis and hemolytic anemia. Without treatment, the severe form of the disease is lethal within the first decade of life. The only curative therapeutic option to date is allogeneic bone marrow transplantation from a matched, related donor, which carries a low risk of morbidity and mortality. Most patients, however, lack a matched donor and are thus managed with palliative therapy, consisting of lifelong transfusion therapy combined with pharmacological chelation to curb iron accumulation. Despite a major improvement in the chelation therapy and supportive care, the major cause of death in these patients is cardiac failure due to secondary hemochromatosis. The goal of globin gene therapy is to offer a potentially curative treatment to patients lacking a matched, related donor, based on the transfer of a regulated beta-globin gene in autologous CD34+ hematopoietic cells collected following G-CSF mobilization. Our clinical trial at Memorial Sloan-Kettering Cancer Center builds on a 20-year long investigation to develop an erythroid-specific vector to regulate beta-globin transgene expression in the progeny of transduced hematopoietic stem cells. To minimize the risks to the patient, the genetically modified cells will be infused after extensive biosafety testing of the transduced cells and following the administration of a reduced intensity (non-myeloablative) conditioning regimen. The protocol will be offered to patients with transfusion-dependent ss-thalassemia who are 15 years or older and lack a matched, related donor.