David M. Barrett

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-modified T cells with specificity for CD19 have shown promise in the treatment of chronic lymphocytic leukemia (CLL). It remains to be established whether chimeric antigen receptor T cells have clinical activity in acute lymphoblastic leukemia (ALL). Two children with relapsed and refractory pre-B-cell ALL received infusions of T cells transduced with anti-CD19 antibody and a T-cell signaling molecule (CTL019 chimeric antigen receptor T cells), at a dose of 1.4×10(6) to 1.2×10(7) CTL019 cells per kilogram of body weight. In both patients, CTL019 T cells expanded to a level that was more than 1000 times as high as the initial engraftment level, and the cells were identified in bone marrow. In addition, the chimeric antigen receptor T cells were observed in the cerebrospinal fluid (CSF), where they persisted at high levels for at least 6 months. Eight grade 3 or 4 adverse events were noted. The cytokine-release syndrome and B-cell aplasia developed in both patients. In one child, the cytokine-release syndrome was severe; cytokine blockade with etanercept and tocilizumab was effective in reversing the syndrome and did not prevent expansion of chimeric antigen receptor T cells or reduce antileukemic efficacy. Complete remission was observed in both patients and is ongoing in one patient at 11 months after treatment. The other patient had a relapse, with blast cells that no longer expressed CD19, approximately 2 months after treatment. Chimeric antigen receptor-modified T cells are capable of killing even aggressive, treatment-refractory acute leukemia cells in vivo. The emergence of tumor cells that no longer express the target indicates a need to target other molecules in addition to CD19 in some patients with ALL.

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.

Chimeric antigen receptor (CAR)-modified T cells and bispecific T cell-engaging antibodies have demonstrated dramatic clinical responses in recent clinical trials. The hallmark of these novel highly active immunotherapies is nonphysiologic T cell activation, which has correlated not only with greatly increased efficacy but also with notable toxicity in some cases. We and others have observed a cytokine release syndrome (CRS), which correlates with both toxicity and efficacy in patients receiving T cell-engaging therapies. In addition to elevations in effector cytokines, such as interferon-γ, cytokines associated with hemophagocytic lymphohistiocytosis or macrophage activation syndrome, such as interleukin (IL)-10 and IL-6, may also be markedly elevated. Whereas corticosteroids may control some of these toxicities, their potential to block T cell activation and abrogate clinical benefit is a concern. Detailed studies of T cell proliferation and the resultant immune activation produced by these novel therapies have led to more targeted approaches that have the potential to provide superior toxicity control without compromising efficacy. One approach we have developed targets IL-6, a prominent cytokine in CRS, using the IL-6R antagonist tocilizumab. We will review the pathophysiology and management options for CRS associated with T cell-engaging therapies.

To provide information about long-term outcome after radical prostatectomy for clinically localized prostatic cancer (stage T2c or lower), we undertook a retrospective analysis of 3,170 consecutive patients (mean age 65.3 +/- 6.4 years, range 31 to 81) with a mean followup of 5 years. Complication rates for patients who underwent prostatectomy before 1988 were compared with those who underwent radical prostatectomy more recently. Of the patients 49 (1.5%), 178 (5.6%), 897 (28%) and 2,047 (65%) had clinical stages T1a, T1b, T2a and T2b,c disease, respectively. The Gleason score was 3 or less in 292 patients (9%) and 7 or greater in 782 (25%). Overall, 438 patients (14%) died, 159 (5%) of cancer. The crude 10 and 15-year survival rates for all patients were 75% and 60%, respectively, which is comparable to the expected survival of a control group (67% and 46%). The cause specific survival rates were 90% and 82%, respectively, metastasis-free survival rates 82% and 76%, local recurrence-free survival rates 83% and 75%, overall recurrence-free rates 72% and 61%, and overall recurrence plus prostate specific antigen progression-free (greater than 0.2 ng./ml.) rates 52% and 40%, respectively. Clinical stage did not significantly affect survival but tumor grade was associated: 10 and 15-year cause specific survival rates were 95% and 93%, respectively, for a Gleason score of 3 or less, 90% and 82%, respectively, for a score of 4 to 6, and 82% and 71%, respectively, for a score of 7 or more. Of all patients 26% received adjuvant treatment (hormonal and/or radiation) within 3 months postoperatively because of advanced local pathological stage (pT3 or higher) or margin positive disease. The 30-day mortality rate was 0.3% (0% for 1,728 patients who underwent surgery in 1988 or later). Only 1 patient in the 70 year or older age group died during hospitalization. Complications decreased with time. In a contemporary group the complications were rectal injury in 0.6% of the patients, colostomy in 0.06%, myocardial infarction in 0.4%, deep venous thrombosis in 1.1%, pulmonary embolism in 0.7% and total urinary incontinence (3 or more pads per day) in 0.8%. Recent intraoperative blood loss was a median of 600 ml., and the incidence of recent need for any transfusion was 31% and it is presently less than 5%. In this series patients undergoing radical prostatectomy for clinically localized prostate cancer were usually healthy and, thus, had low co-morbidity. Survival rates at 10 and 15 years compare favorably with those of an age-matched control group.(ABSTRACT TRUNCATED AT 400 WORDS)