Yvette Bernal

CD19-targeted T cells rapidly induce molecular remissions in adults with chemotherapy-refractory acute lymphoblastic leukemia.

Five adults with chemotherapy-refractory B-ALL were induced into molecular remissions after treatment with CD19 CAR-targeted T cells. CARving a Niche for Cancer Immunotherapy Acute lymphoblastic leukemia (ALL) is a cancer of the white blood cells that fend off infection. It’s most common in children but—as with many diseases that primarily affect children—has a much worse prognosis when it affects adults. Adults with relapsed disease have a very low chance of survival, and new therapies are desperately needed. Now, Brentjens et al. test T cells engineered to target CD19, which is expressed on both healthy B lymphocytes and B-ALL cells, in five chemotherapy-refractory adult B-ALL patients. Here, the authors treat patients with the patients’ own T cells altered to express not only CD19 but also a fusion of the costimulatory molecule CD28 with CD3ζ chain—so-called “second-generation chimeric antigen receptor (CAR) T cells.” All patients treated with these cells achieved tumor eradication and complete remission. These CAR T cells were well tolerated, although there was substantial cytokine release in some patients that correlated to tumor burden. These patients were treated with steroid therapy. Long-term follow-up in four of these patients was not possible because the CAR T cell therapy allowed these patients to be eligible for subsequent hematopoietic stem cell transplant (HSCT), which resulted in restored hematopoiesis. The remaining patient experienced a relapse of CD19+ cells that coincided with the lack of persistence of the CAR T cells from circulation. These data suggest that subsequent transfusions should be considered for patients unable to undergo HSCT. Adults with relapsed B cell acute lymphoblastic leukemia (B-ALL) have a dismal prognosis. Only those patients able to achieve a second remission with no minimal residual disease (MRD) have a hope for long-term survival in the context of a subsequent allogeneic hematopoietic stem cell transplantation (allo-HSCT). We have treated five relapsed B-ALL subjects with autologous T cells expressing a CD19-specific CD28/CD3ζ second-generation dual-signaling chimeric antigen receptor (CAR) termed 19-28z. All patients with persistent morphological disease or MRD+ disease upon T cell infusion demonstrated rapid tumor eradication and achieved MRD− complete remissions as assessed by deep sequencing polymerase chain reaction. Therapy was well tolerated, although significant cytokine elevations, specifically observed in those patients with morphologic evidence of disease at the time of treatment, required lymphotoxic steroid therapy to ameliorate cytokine-mediated toxicities. Indeed, cytokine elevations directly correlated to tumor burden at the time of CAR-modified T cell infusions. Tumor cells from one patient with relapsed disease after CAR-modified T cell therapy, who was ineligible for additional allo-HSCT or T cell therapy, exhibited persistent expression of CD19 and sensitivity to autologous 19-28z T cell–mediated cytotoxicity, which suggests potential clinical benefit of additional CAR-modified T cell infusions. These results demonstrate the marked antitumor efficacy of 19-28z CAR-modified T cells in patients with relapsed/refractory B-ALL and the reliability of this therapy to induce profound molecular remissions, forming a highly effective bridge to potentially curative therapy with subsequent allo-HSCT.

Efficacy and toxicity management of 19-28z CAR T cell therapy in B cell acute lymphoblastic leukemia.

CD19 CAR T cell therapy induces complete remissions in 88% of 16 adult patients with relapsed or refractory acute lymphoblastic leukemia. CARving Out a Niche for CAR T Cell Immunotherapy Relapsed or refractory B acute lymphoblastic leukemia (B-ALL) in adults has a poor prognosis, with an expected median survival of less than 6 months. An emerging therapy for adult B-ALL is through T cells that target tumor cells with chimeric antigen receptors (CARs). Davila et al. now report the results of a phase 1 clinical trial of CAR T cells in 16 relapsed or refractory adult patients. The CD19-targeting CAR T cell therapy resulted in an 88% complete response rate, which allowed most of the patients to transition to allogeneic hematopoietic stem cell transplantation—the current standard of care. Moreover, the authors carefully characterized cytokine release syndrome (CRS), which is a series of toxicities associated with CAR T cell therapy. They found that serum C-reactive protein (CRP) associated with the severity of CRS, which should allow for identification of the subset of patients who will likely require therapeutic intervention with corticosteroids or interleukin-6 receptor blockade to curb the CRS. This is especially important because treatment for CRS may limit the efficacy of the CAR T cell therapy. These data support the need for further multicenter trials for CAR T cell therapy. We report on 16 patients with relapsed or refractory B cell acute lymphoblastic leukemia (B-ALL) that we treated with autologous T cells expressing the 19-28z chimeric antigen receptor (CAR) specific to the CD19 antigen. The overall complete response rate was 88%, which allowed us to transition most of these patients to a standard-of-care allogeneic hematopoietic stem cell transplant (allo-SCT). This therapy was as effective in high-risk patients with Philadelphia chromosome–positive (Ph+) disease as in those with relapsed disease after previous allo-SCT. Through systematic analysis of clinical data and serum cytokine levels over the first 21 days after T cell infusion, we have defined diagnostic criteria for a severe cytokine release syndrome (sCRS), with the goal of better identifying the subset of patients who will likely require therapeutic intervention with corticosteroids or interleukin-6 receptor blockade to curb the sCRS. Additionally, we found that serum C-reactive protein, a readily available laboratory study, can serve as a reliable indicator for the severity of the CRS. Together, our data provide strong support for conducting a multicenter phase 2 study to further evaluate 19-28z CAR T cells in B-ALL and a road map for patient management at centers now contemplating the use of CAR T cell therapy.

Safety and persistence of adoptively transferred autologous CD19-targeted T cells in patients with relapsed or chemotherapy refractory B-cell leukemias

We report the findings from the first 10 patients with chemotherapy-refractory chronic lymphocytic leukemia (CLL) or relapsed B-cell acute lymphoblastic leukemia (ALL) we have enrolled for treatment with autologous T cells modified to express 19-28z, a second-generation chimeric antigen (Ag) receptor specific to the B-cell lineage Ag CD19. Eight of the 9 treated patients tolerated 19-28z(+) T-cell infusions well. Three of 4 evaluable patients with bulky CLL who received prior conditioning with cyclophosphamide exhibited either a significant reduction or a mixed response in lymphadenopathy without concomitant development of B-cell aplasia. In contrast, one patient with relapsed ALL who was treated in remission with a similar T-cell dose developed a predicted B-cell aplasia. The short-term persistence of infused T cells was enhanced by prior cyclophosphamide administration and inversely proportional to the peripheral blood tumor burden. Further analyses showed rapid trafficking of modified T cells to tumor and retained ex vivo cytotoxic potential of CD19-targeted T cells retrieved 8 days after infusion. We conclude that this adoptive T-cell approach is promising and more likely to show clinical benefit in the setting of prior conditioning chemotherapy and low tumor burden or minimal residual disease. These studies are registered at www.clinicaltrials.org as #NCT00466531 (CLL protocol) and #NCT01044069 (B-ALL protocol).

Treatment of Chronic Lymphocytic Leukemia With Genetically Targeted Autologous T Cells: Case Report of an Unforeseen Adverse Event in a Phase I Clinical Trial

666 www.moleculartherapy.org vol. 18 no. 4 april 2010 chemotherapy was administered before infusion of the same T-cell dose, developed a syndrome of hypotension, dyspnea, and renal failure following T-cell infusion. Subject 4 died 4 days after administration of cyclophosphamide and modified T cells. Herein we describe the chronology of his treatment and report the findings of an extensive postmortem analysis.

Phase 2 trial of a multivalent WT1 peptide vaccine (galinpepimut-S) in acute myeloid leukemia

A National Cancer Institute consensus study on prioritization of cancer antigens ranked the Wilms tumor 1 (WT1) protein as the top immunotherapy target in cancer. We previously reported a pilot study of a multivalent WT1 peptide vaccine (galinpepimut-S) in acute myeloid leukemia (AML) patients. We have now conducted a phase 2 study investigating this vaccine in adults with AML in first complete remission (CR1). Patients received 6 vaccinations administered over 10 weeks with the potential to receive 6 additional monthly doses if they remained in CR1. Immune responses (IRs) were evaluated after the 6th and 12th vaccinations by CD4+ T-cell proliferation, CD8+ T-cell interferon-γ secretion (enzyme-linked immunospot), or the CD8-relevant WT1 peptide major histocompatibility complex tetramer assay (HLA-A*02 patients only). Twenty-two patients (7 males; median age, 64 years) were treated. Fourteen patients (64%) completed ≥6 vaccinations, and 9 (41%) received all 12 vaccine doses. Fifteen patients (68%) relapsed, and 10 (46%) died. The vaccine was well tolerated, with the most common toxicities being grade 1/2 injection site reactions (46%), fatigue (32%), and skin induration (32%). Median disease-free survival from CR1 was 16.9 months, whereas the overall survival from diagnosis has not yet been reached but is estimated to be ≥67.6 months. Nine of 14 tested patients (64%) had an IR in ≥1 assay (CD4 or CD8). These results indicated that the WT1 vaccine was well tolerated, stimulated a specific IR, and was associated with survival in excess of 5 years in this cohort of patients. This trial was registered at www.clinicaltrials.gov as #NCT01266083.

Clinical and Biological Correlates of Neurotoxicity Associated with CAR T-cell Therapy in Patients with B-cell Acute Lymphoblastic Leukemia

CD19-specific chimeric antigen receptor (CAR) T-cell therapy is highly effective against relapsed or refractory acute lymphoblastic leukemia (ALL), but is hindered by neurotoxicity. In 53 adult patients with ALL, we found a significant association of severe neurotoxicity with high pretreatment disease burden, higher peak CAR T-cell expansion, and early and higher elevations of proinflammatory cytokines in blood. Patients with severe neurotoxicity had evidence of blood-cerebrospinal fluid (CSF) barrier disruption correlating with neurotoxicity grade without association with CSF white blood cell count or CAR T-cell quantity in CSF. Proinflammatory cytokines were enriched in CSF during severe neurotoxicity with disproportionately high levels of IL6, IL8, MCP1, and IP10, suggesting central nervous system-specific production. Seizures, seizure-like activity, myoclonus, and neuroimaging characteristics suggested excitatory neurotoxicity, and we found elevated levels of endogenous excitatory agonists in CSF during neurotoxicity.Significance: We detail the neurologic symptoms and blood, CSF, and neuroimaging correlates of neurotoxicity associated with CD19 CAR T cells and identify neurotoxicity risk factors. Our findings implicate cellular components other than T cells and suggest novel links between systemic inflammation and characteristic neurotoxicity symptoms. Cancer Discov; 8(8); 958-71. ©2018 AACR.This article is highlighted in the In This Issue feature, p. 899.

475. Phase I Clinical Trial of Autologous CD19-Targeted 19-28z CAR T Cells in Adult Patients With Relapsed or Refractory B-ALL

Adult patients with relapsed or refractory (R/R) acute lymphoblastic leukemia (ALL) have a dismal prognosis with a median overall survival (OS) < 6 months. Salvage chemotherapy is ineffective and often induces only a transient remission. We previously reported high anti-tumor activity of autologous T cells genetically modified to express 19-28z chimeric antigen receptor (CAR) targeting CD19 antigen in adult patients with ALL (Davila M et al. Sci Transl Med 2014). Herein, we report updated results and long-term outcome from our phase I clinical trial of 19-28z CAR T cells in adult patients with R/R ALL (NCT01044069).