Noelle V. Frey

Chimeric Antigen Receptor T Cells for Sustained Remissions in Leukemia

BACKGROUND Relapsed acute lymphoblastic leukemia (ALL) is difficult to treat despite the availability of aggressive therapies. Chimeric antigen receptor-modified T cells targeting CD19 may overcome many limitations of conventional therapies and induce remission in patients with refractory disease. METHODS We infused autologous T cells transduced with a CD19-directed chimeric antigen receptor (CTL019) lentiviral vector in patients with relapsed or refractory ALL at doses of 0.76×10(6) to 20.6×10(6) CTL019 cells per kilogram of body weight. Patients were monitored for a response, toxic effects, and the expansion and persistence of circulating CTL019 T cells. RESULTS A total of 30 children and adults received CTL019. Complete remission was achieved in 27 patients (90%), including 2 patients with blinatumomab-refractory disease and 15 who had undergone stem-cell transplantation. CTL019 cells proliferated in vivo and were detectable in the blood, bone marrow, and cerebrospinal fluid of patients who had a response. Sustained remission was achieved with a 6-month event-free survival rate of 67% (95% confidence interval [CI], 51 to 88) and an overall survival rate of 78% (95% CI, 65 to 95). At 6 months, the probability that a patient would have persistence of CTL019 was 68% (95% CI, 50 to 92) and the probability that a patient would have relapse-free B-cell aplasia was 73% (95% CI, 57 to 94). All the patients had the cytokine-release syndrome. Severe cytokine-release syndrome, which developed in 27% of the patients, was associated with a higher disease burden before infusion and was effectively treated with the anti-interleukin-6 receptor antibody tocilizumab. CONCLUSIONS Chimeric antigen receptor-modified T-cell therapy against CD19 was effective in treating relapsed and refractory ALL. CTL019 was associated with a high remission rate, even among patients for whom stem-cell transplantation had failed, and durable remissions up to 24 months were observed. (Funded by Novartis and others; CART19 ClinicalTrials.gov numbers, NCT01626495 and NCT01029366.).

Chimeric antigen receptor T cells persist and induce sustained remissions in relapsed refractory chronic lymphocytic leukemia

CAR T cells persist and sustain remissions in advanced chronic lymphocytic leukemia. CAR T cells for the long haul Immunotherapy is one of the most promising avenues of cancer therapy, with the potential to induce sustained remissions in patients with refractory disease. Studies with chimeric antigen receptor (CAR)–modified T cells have paved the way in patients with relapsed and refractory chronic lymphocytic leukemia. Porter et al. now report the mature results from their initial CAR T cell trial. CAR T cell persistence correlated with clinical responses, and these cells were functional up to 4 years after treatment. No patient who achieved complete remission relapsed, and no minimal residual disease was detected, suggesting that in a subset of patients, CAR T cells may drive disease eradication. Patients with multiply relapsed or refractory chronic lymphocytic leukemia (CLL) have a poor prognosis. Chimeric antigen receptor (CAR)–modified T cells targeting CD19 have the potential to improve on the low complete response rates with conventional therapies by inducing sustained remissions in patients with refractory B cell malignancies. We previously reported preliminary results on three patients with refractory CLL. We report the mature results from our initial trial using CAR-modified T cells to treat 14 patients with relapsed and refractory CLL. Autologous T cells transduced with a CD19-directed CAR (CTL019) lentiviral vector were infused into patients with relapsed/refractory CLL at doses of 0.14 × 108 to 11 × 108 CTL019 cells (median, 1.6 × 108 cells). Patients were monitored for toxicity, response, expansion, and persistence of circulating CTL019 T cells. The overall response rate in these heavily pretreated CLL patients was 8 of 14 (57%), with 4 complete remissions (CR) and 4 partial remissions (PR). The in vivo expansion of the CAR T cells correlated with clinical responses, and the CAR T cells persisted and remained functional beyond 4 years in the first two patients achieving CR. No patient in CR has relapsed. All responding patients developed B cell aplasia and experienced cytokine release syndrome, coincident with T cell proliferation. Minimal residual disease was not detectable in patients who achieved CR, suggesting that disease eradication may be possible in some patients with advanced CLL.

Blockade of Lymphocyte Chemotaxis in Visceral Graft-versus-Host Disease

BACKGROUND Graft-versus-host disease (GVHD) is a major barrier to successful allogeneic hematopoietic stem-cell transplantation (HSCT). The chemokine receptor CCR5 appears to play a role in alloreactivity. We tested whether CCR5 blockade would be safe and limit GVHD in humans. METHODS We tested the in vitro effect of the CCR5 antagonist maraviroc on lymphocyte function and chemotaxis. We then enrolled 38 high-risk patients in a single-group phase 1 and 2 study of reduced-intensity allogeneic HSCT that combined maraviroc with standard GVHD prophylaxis. RESULTS Maraviroc inhibited CCR5 internalization and lymphocyte chemotaxis in vitro without impairing T-cell function or formation of hematopoietic-cell colonies. In 35 patients who could be evaluated, the cumulative incidence rate (±SE) of grade II to IV acute GVHD was low at 14.7±6.2% on day 100 and 23.6±7.4% on day 180. Acute liver and gut GVHD were not observed before day 100 and remained uncommon before day 180, resulting in a low cumulative incidence of grade III or IV GVHD on day 180 (5.9±4.1%). The 1-year rate of death that was not preceded by disease relapse was 11.7±5.6% without excessive rates of relapse or infection. Serum from patients receiving maraviroc prevented CCR5 internalization by CCL5 and blocked T-cell chemotaxis in vitro, providing evidence of antichemotactic activity. CONCLUSIONS In this study, inhibition of lymphocyte trafficking was a specific and potentially effective new strategy to prevent visceral acute GVHD. (Funded by Pfizer and others; ClinicalTrials.gov number, NCT00948753.).

Identification of Predictive Biomarkers for Cytokine Release Syndrome after Chimeric Antigen Receptor T-cell Therapy for Acute Lymphoblastic Leukemia.

UNLABELLED Chimeric antigen receptor (CAR)-modified T cells with anti-CD19 specificity are a highly effective novel immune therapy for relapsed/refractory acute lymphoblastic leukemia. Cytokine release syndrome (CRS) is the most significant and life-threatening toxicity. To improve understanding of CRS, we measured cytokines and clinical biomarkers in 51 CTL019-treated patients. Peak levels of 24 cytokines, including IFNγ, IL6, sgp130, and sIL6R, in the first month after infusion were highly associated with severe CRS. Using regression modeling, we could accurately predict which patients would develop severe CRS with a signature composed of three cytokines. Results were validated in an independent cohort. Changes in serum biochemical markers, including C-reactive protein and ferritin, were associated with CRS but failed to predict development of severe CRS. These comprehensive profiling data provide novel insights into CRS biology and, importantly, represent the first data that can accurately predict which patients have a high probability of becoming critically ill. SIGNIFICANCE CRS is the most common severe toxicity seen after CAR T-cell treatment. We developed models that can accurately predict which patients are likely to develop severe CRS before they become critically ill, which improves understanding of CRS biology and may guide future cytokine-directed therapy. Cancer Discov; 6(6); 664-79. ©2016 AACR.See related commentary by Rouce and Heslop, p. 579This article is highlighted in the In This Issue feature, p. 561.

A Phase I Study of the Mammalian Target of Rapamycin Inhibitor Sirolimus and MEC Chemotherapy in Relapsed and Refractory Acute Myelogenous Leukemia

Purpose: Inhibiting mammalian target of rapamycin (mTOR) signaling in acute myelogenous leukemia (AML) blasts and leukemic stem cells may enhance their sensitivity to cytotoxic agents. We sought to determine the safety and describe the toxicity of this approach by adding the mTOR inhibitor, sirolimus (rapamycin), to intensive AML induction chemotherapy. Experimental Design: We performed a phase I dose escalation study of sirolimus with the chemotherapy regimen MEC (mitoxantrone, etoposide, and cytarabine) in patients with relapsed, refractory, or untreated secondary AML. Results: Twenty-nine subjects received sirolimus and MEC across five dose levels. Dose-limiting toxicities were irreversible marrow aplasia and multiorgan failure. The maximum tolerated dose (MTD) of sirolimus was determined to be a 12 mg loading dose on day 1 followed by 4 mg/d on days 2 to 7, concurrent with MEC chemotherapy. Complete or partial remissions occurred in 6 (22%) of the 27 subjects who completed chemotherapy, including 3 (25%) of the 12 subjects treated at the MTD. At the MTD, measured rapamycin trough levels were within the therapeutic range for solid organ transplantation. However, direct measurement of the mTOR target p70 S6 kinase phosphorylation in marrow blasts from these subjects only showed definite target inhibition in one of five evaluable samples. Conclusions: Sirolimus and MEC is an active and feasible regimen. However, as administered in this study, the synergy between MEC and sirolimus was not confirmed. Future studies are planned with different schedules to clarify the clinical and biochemical effects of sirolimus in AML and to determine whether target inhibition predicts chemotherapy response. (Clin Cancer Res 2009;15(21):6732–9)

Cytokine Release Syndrome After Chimeric Antigen Receptor T Cell Therapy for Acute Lymphoblastic Leukemia.

Objective: Initial success with chimeric antigen receptor–modified T cell therapy for relapsed/refractory acute lymphoblastic leukemia is leading to expanded use through multicenter trials. Cytokine release syndrome, the most severe toxicity, presents a novel critical illness syndrome with limited data regarding diagnosis, prognosis, and therapy. We sought to characterize the timing, severity, and intensive care management of cytokine release syndrome after chimeric antigen receptor–modified T cell therapy. Design: Retrospective cohort study. Setting: Academic children’s hospital. Patients: Thirty-nine subjects with relapsed/refractory acute lymphoblastic leukemia treated with chimeric antigen receptor–modified T cell therapy on a phase I/IIa clinical trial (ClinicalTrials.gov number NCT01626495). Interventions: All subjects received chimeric antigen receptor–modified T cell therapy. Thirteen subjects with cardiovascular dysfunction were treated with the interleukin-6 receptor antibody tocilizumab. Measurements and Main Results: Eighteen subjects (46%) developed grade 3–4 cytokine release syndrome, with prolonged fever (median, 6.5 d), hyperferritinemia (median peak ferritin, 60,214 ng/mL), and organ dysfunction. Fourteen (36%) developed cardiovascular dysfunction treated with vasoactive infusions a median of 5 days after T cell therapy. Six (15%) developed acute respiratory failure treated with invasive mechanical ventilation a median of 6 days after T cell therapy; five met criteria for acute respiratory distress syndrome. Encephalopathy, hepatic, and renal dysfunction manifested later than cardiovascular and respiratory dysfunction. Subjects had a median of 15 organ dysfunction days (interquartile range, 8–20). Treatment with tocilizumab in 13 subjects resulted in rapid defervescence (median, 4 hr) and clinical improvement. Conclusions: Grade 3–4 cytokine release syndrome occurred in 46% of patients following T cell therapy for relapsed/refractory acute lymphoblastic leukemia. Clinicians should be aware of expanding use of this breakthrough therapy and implications for critical care units in cancer centers.

The management of posttransplant lymphoproliferative disorder.

Posttransplant lymphoproliferative disorder (PTLD) is a life-threatening complication of allogeneic hematopoietic stem cell and solid organ transplantation. Most cases are EBV-positive B-cell neoplasms, which occur in the setting of pharmacologically impaired cellular immunity. Several different treatment strategies including cytotoxic antitumor therapy, anti-B-cell monoclonal antibody therapy, antiviral therapy, and modalities aimed at restoration of EBV-specific cellular immunity have been employed. In addition, efforts to identify patients at high risk for PTLD have resulted in attempts at prophylactic and preemptive therapies. In this review we discuss the available literature on differing approaches to PTLD management, identify areas in need of further investigation, and, when possible, make general recommendations. Reduction of immunosuppression remains the mainstay of first-line treatment. Accumulating evidence supports the role of rituximab as second-line therapy with cytotoxic chemotherapy reserved for specific circumstances. Further investigations are needed to better define the role of more novel and less widely available therapies such as the adoptive transfer of EBV-specific T cells and optimization of antiviral therapies.

Graft-versus-host disease after donor leukocyte infusions: presentation and management

Donor leukocyte infusion (DLI) is used after both myeloablative and non-myeloablative stem-cell transplantation to treat and prevent relapse, to establish full donor chimerism, and to treat and prevent infections. The major treatment-related complication of DLI is graft-versus-host disease (GVHD). The presentation and treatment of GVHD after DLI is similar to its presentation and treatment after stem-cell transplantation, with some notable exceptions. While GVHD and graft-versus-tumor (GVT) effects are highly correlated after DLI, some patients experience remission without GVHD. Studies to define tumor-specific target antigens and GVT effector cells, as well as strategies of donor T-cell manipulation and optimization of DLI dose and schedule, may ultimately lead to the consistent ability to separate GVHD from GVT activity, improvement in the safety and specificity of DLI, and enhancement of the anti-tumor activity of donor T cells.

Functional Unresponsiveness and Replicative Senescence of Myeloid Leukemia Antigen-specific CD8 + T Cells After Allogeneic Stem Cell Transplantation

Purpose: The therapeutic effect of allogeneic hematopoietic stem cell transplantation (HSCT) for patients with myeloid malignancies has been attributed in part to a graft-versus-leukemia effect that is dependent on donor T lymphocytes. CD8+ T-cell responses to MHC class I–restricted tumor epitopes, not just allogeneic antigens, may help mediate antileukemia effects after HSCT, but the specificity and function of such cells are not completely understood. Experimental Design: We examined the diversity, phenotype, and functional potential of leukemia-associated antigen-specific CD8+ T cells in patients with myeloid leukemia following allogeneic HSCT. Screening for antigen-specific T cells was accomplished with a peptide/MHC tetramer library. Results: Patients with acute myelogenous leukemia or chronic myelogenous leukemia in remission following HSCT exhibited significant numbers of peripheral blood CD8+ T cells that recognized varying combinations of epitopes derived from leukemia-associated antigens. However, these cells failed to proliferate, release cytokines, or degranulate in response to antigen-specific stimuli. As early as 2 months after HSCT, CD8+ T cells from patients were predominantly CD28− CD57+ and had relatively short telomeres, consistent with cellular senescence. Conclusions: Circulating leukemia-specific CD8+ T cells are prominent in myeloid leukemia patients after HSCT, but such cells are largely functionally unresponsive, most likely due to replicative senescence. These findings carry important implications for the understanding of the graft-versus-leukemia effect and for the rational design of immunotherapeutic strategies for patients with myeloid leukemias.

Primary lymphomas of the cervix and uterus: The University of Pennsylvania's experience and a review of the literature

Primary lymphomas of the cervix and uterus are rare with ∼150 cases reported in the world literature to date. Appropriate diagnosis is often delayed until the post-operative setting as clinical and radiographic presentations are non-specific. Several sub-types of lymphoma arising primarily in the cervix or uterus have been reported with diffuse large B-Cell lymphoma (DLBCL) being the most frequent. Due to the low incidence of this disease, no randomized clinical trials exist to help guide treatment. This study reports the experience of four patients with primary lymphomas of the uterus and cervix that reflect the heterogeneity of cases reported in the literature to date. The patients had a mean age at diagnosis of 46 (range 35 – 56) and presented with abnormal uterine bleeding. One patient was diagnosed by total abdominal hysterectomy (TAH), two patients were diagnosed by cervical biopsy and one patient was diagnosed by endometrial biopsy. Three patients had DLBCL and one patient had marginal zone lymphoma (MZL). All patients had stage IIE disease. Of the patients with DLBCL, one received chemotherapy followed by TAH and two received TAH followed by chemotherapy. Two of these three patients remain disease-free post-initial therapy with the third now disease-free post-salvage therapy and autologous stem cell transplant. The patient with MZL was treated with TAH alone and remains disease-free. Based on the case series and a review of available literature, primary lymphomas of the uterus or cervix are rare and require an individualized approach to treatment. In general, patients with limited stage disease should be treated with localized and systemic therapy to optimize chances of cure.