Scott L. Weiss

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.

Developing a clinically feasible personalized medicine approach to pediatric septic shock.

RATIONALE Using microarray data, we previously identified gene expression-based subclasses of septic shock with important phenotypic differences. The subclass-defining genes correspond to adaptive immunity and glucocorticoid receptor signaling. Identifying the subclasses in real time has theranostic implications, given the potential for immune-enhancing therapies and controversies surrounding adjunctive corticosteroids for septic shock. OBJECTIVES To develop and validate a real-time subclassification method for septic shock. METHODS Gene expression data for the 100 subclass-defining genes were generated using a multiplex messenger RNA quantification platform (NanoString nCounter) and visualized using gene expression mosaics. Study subjects (n = 168) were allocated to the subclasses using computer-assisted image analysis and microarray-based reference mosaics. A gene expression score was calculated to reduce the gene expression patterns to a single metric. The method was tested prospectively in a separate cohort (n = 132). MEASUREMENTS AND MAIN RESULTS The NanoString-based data reproduced two septic shock subclasses. As previously, one subclass had decreased expression of the subclass-defining genes. The gene expression score identified this subclass with an area under the curve of 0.98 (95% confidence interval [CI95] = 0.96-0.99). Prospective testing of the subclassification method corroborated these findings. Allocation to this subclass was independently associated with mortality (odds ratio = 2.7; CI95 = 1.2-6.0; P = 0.016), and adjunctive corticosteroids prescribed at physician discretion were independently associated with mortality in this subclass (odds ratio = 4.1; CI95 = 1.4-12.0; P = 0.011). CONCLUSIONS We developed and tested a gene expression-based classification method for pediatric septic shock that meets the time constraints of the critical care environment, and can potentially inform therapeutic decisions.

Delayed antimicrobial therapy increases mortality and organ dysfunction duration in pediatric sepsis.

Objectives: Delayed antimicrobials are associated with poor outcomes in adult sepsis, but data relating antimicrobial timing to mortality and organ dysfunction in pediatric sepsis are limited. We sought to determine the impact of antimicrobial timing on mortality and organ dysfunction in pediatric patients with severe sepsis or septic shock. Design: Retrospective observational study. Setting: PICU at an academic medical center. Patients: One hundred thirty patients treated for severe sepsis or septic shock. Interventions: None. Measurements and Main Results: We determined if hourly delays from sepsis recognition to initial and first appropriate antimicrobial administration were associated with PICU mortality (primary outcome); ventilator-free, vasoactive-free, and organ failure–free days; and length of stay. Median time from sepsis recognition to initial antimicrobial administration was 140 minutes (interquartile range, 74–277 min) and to first appropriate antimicrobial was 177 minutes (90–550 min). An escalating risk of mortality was observed with each hour delay from sepsis recognition to antimicrobial administration, although this did not achieve significance until 3 hours. For patients with more than 3-hour delay to initial and first appropriate antimicrobials, the odds ratio for PICU mortality was 3.92 (95% CI, 1.27–12.06) and 3.59 (95% CI, 1.09–11.76), respectively. These associations persisted after adjustment for individual confounders and a propensity score analysis. After controlling for severity of illness, the odds ratio for PICU mortality increased to 4.84 (95% CI, 1.45–16.2) and 4.92 (95% CI, 1.30–18.58) for more than 3-hour delay to initial and first appropriate antimicrobials, respectively. Initial antimicrobial administration more than 3 hours was also associated with fewer organ failure–free days (16 [interquartile range, 1–23] vs 20 [interquartile range, 6–26]; p = 0.04). Conclusions: Delayed antimicrobial therapy was an independent risk factor for mortality and prolonged organ dysfunction in pediatric sepsis.

Pediatric severe sepsis in U.S. children's hospitals.

Objectives: To compare the prevalence, resource utilization, and mortality for pediatric severe sepsis identified using two established identification strategies. Design: Observational cohort study from 2004 to 2012. Setting: Forty-four pediatric hospitals contributing data to the Pediatric Health Information Systems database. Patients: Children 18 years old or younger. Measurements and Main Results: We identified patients with severe sepsis or septic shock by using two International Classification of Diseases, 9th edition, Clinical Modification–based coding strategies: 1) combinations of International Classification of Diseases, 9th edition, Clinical Modification codes for infection plus organ dysfunction (combination code cohort); 2) International Classification of Diseases, 9th edition, Clinical Modification codes for severe sepsis and septic shock (sepsis code cohort). Outcomes included prevalence of severe sepsis, as well as hospital and ICU length of stay, and mortality. Outcomes were compared between the two cohorts examining aggregate differences over the study period and trends over time. The combination code cohort identified 176,124 hospitalizations (3.1% of all hospitalizations), whereas the sepsis code cohort identified 25,236 hospitalizations (0.45%), a seven-fold difference. Between 2004 and 2012, the prevalence of sepsis increased from 3.7% to 4.4% using the combination code cohort and from 0.4% to 0.7% using the sepsis code cohort (p < 0.001 for trend in each cohort). Length of stay (hospital and ICU) and costs decreased in both cohorts over the study period (p < 0.001). Overall, hospital mortality was higher in the sepsis code cohort than the combination code cohort (21.2% [95% CI, 20.7–21.8] vs 8.2% [95% CI, 8.0–8.3]). Over the 9-year study period, there was an absolute reduction in mortality of 10.9% (p < 0.001) in the sepsis code cohort and 3.8% (p < 0.001) in the combination code cohort. Conclusions: Prevalence of pediatric severe sepsis increased in the studied U.S. children’s hospitals over the past 9 years, whereas resource utilization and mortality decreased. Epidemiologic estimates of pediatric severe sepsis varied up to seven-fold depending on the strategy used for case ascertainment.

Defining pediatric sepsis by different criteria: Discrepancies in populations and implications for clinical practice

Objective: Pediatric patients with sepsis are identified using related but distinct criteria for clinical, research, and administrative purposes. The overlap between these criteria will affect the validity of extrapolating data across settings. We sought to quantify the extent of agreement among different criteria for pediatric severe sepsis/septic shock and to detect systematic differences between these cohorts. Design: Observational cohort study. Setting: Forty-two bed pediatric intensive care unit at an academic medical center. Patients: A total of 1,729 patients ⩽18 yrs-old. Interventions: None. Measurements and Main Results: All patients were screened for severe sepsis or septic shock using consensus guidelines (research criteria), diagnosis by healthcare professionals (clinical criteria), and International Classification of Diseases, Ninth Revision, Clinical Modification codes (administrative criteria). Cohen’s &kgr; determined the level of agreement among criteria, and patient characteristics were compared between cohorts. Ninety (5.2%) patients were identified by research, 96 (5.6%) by clinical, and 103 (6.0%) by administrative criteria. The &kgr; ± standard error for pair-wise comparisons was 0.67 ± 0.04 for research-clinical, 0.52 ± 0.05 for research-administrative, and 0.55 ± 0.04 for clinical-administrative. Of the patients in the clinical cohort, 67% met research and 58% met administrative criteria. The research cohort exhibited a higher Pediatric Index of Mortality-2 score (median, interquartile range 5.2, 1.6-13.3) than the clinical (3.6, 1.1-6.2) and administrative (3.9, 1.0-6.0) cohorts (p = .005), an increased requirement for vasoactive infusions (74%, 57%, and 45%, p < .001), and a potential bias toward an increased proportion with respiratory dysfunction compared with clinical practice. Conclusions: Although research, clinical, and administrative criteria yielded a similar incidence (5%-6%) for pediatric severe sepsis/septic shock, there was only a moderate level of agreement in the patients identified by different criteria. One third of patients diagnosed clinically with sepsis would not have been included in studies based on consensus guidelines or International Classification of Diseases, Ninth Revision, Clinical Modification codes. Differences in patient selection need to be considered when extrapolating data across settings.

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.

Testing the Prognostic Accuracy of the Updated Pediatric Sepsis Biomarker Risk Model

Background We previously derived and validated a risk model to estimate mortality probability in children with septic shock (PERSEVERE; PEdiatRic SEpsis biomarkEr Risk modEl). PERSEVERE uses five biomarkers and age to estimate mortality probability. After the initial derivation and validation of PERSEVERE, we combined the derivation and validation cohorts (n = 355) and updated PERSEVERE. An important step in the development of updated risk models is to test their accuracy using an independent test cohort. Objective To test the prognostic accuracy of the updated version PERSEVERE in an independent test cohort. Methods Study subjects were recruited from multiple pediatric intensive care units in the United States. Biomarkers were measured in 182 pediatric subjects with septic shock using serum samples obtained during the first 24 hours of presentation. The accuracy of PERSEVERE 28-day mortality risk estimate was tested using diagnostic test statistics, and the net reclassification improvement (NRI) was used to test whether PERSEVERE adds information to a physiology-based scoring system. Results Mortality in the test cohort was 13.2%. Using a risk cut-off of 2.5%, the sensitivity of PERSEVERE for mortality was 83% (95% CI 62–95), specificity was 75% (68–82), positive predictive value was 34% (22–47), and negative predictive value was 97% (91–99). The area under the receiver operating characteristic curve was 0.81 (0.70–0.92). The false positive subjects had a greater degree of organ failure burden and longer intensive care unit length of stay, compared to the true negative subjects. When adding PERSEVERE to a physiology-based scoring system, the net reclassification improvement was 0.91 (0.47–1.35; p<0.001). Conclusions The updated version of PERSEVERE estimates mortality probability reliably in a heterogeneous test cohort of children with septic shock and provides information over and above a physiology-based scoring system.

Corticosteroids are associated with repression of adaptive immunity gene programs in pediatric septic shock.

RATIONALE Corticosteroids are prescribed commonly for patients with septic shock, but their use remains controversial and concerns remain regarding side effects. OBJECTIVES To determine the effect of adjunctive corticosteroids on the genomic response of pediatric septic shock. METHODS We retrospectively analyzed an existing transcriptomic database of pediatric septic shock. Subjects receiving any formulation of systemic corticosteroids at the time of blood draw for microarray analysis were classified in the septic shock corticosteroid group. We compared normal control subjects (n = 52), a septic shock no corticosteroid group (n = 110), and a septic shock corticosteroid group (n = 70) using analysis of variance. Genes differentially regulated between the no corticosteroid group and the corticosteroid group were analyzed using Ingenuity Pathway Analysis. MEASUREMENTS AND MAIN RESULTS The two study groups did not differ with respect to illness severity, organ failure burden, mortality, or mortality risk. There were 319 gene probes differentially regulated between the no corticosteroid group and the corticosteroid group. These genes corresponded predominately to adaptive immunity-related signaling pathways, and were down-regulated relative to control subjects. Notably, the degree of down-regulation was significantly greater in the corticosteroid group, compared with the no corticosteroid group. A similar pattern was observed for genes corresponding to the glucocorticoid receptor signaling pathway. CONCLUSIONS Administration of corticosteroids in pediatric septic shock is associated with additional repression of genes corresponding to adaptive immunity. These data should be taken into account when considering the benefit to risk ratio of adjunctive corticosteroids for septic shock.

Post-ICU admission fluid balance and pediatric septic shock outcomes: A risk-stratified analysis

Objective:Observed associations between fluid balance and septic shock outcomes are likely confounded by initial mortality risk. We conducted a risk-stratified analysis of the association between post-ICU admission fluid balance and pediatric septic shock outcomes. Design:Retrospective analysis of an ongoing multicenter pediatric septic shock clinical and biological database. Setting:Seventeen PICUs in the United States. Patients:Three hundred and seventeen children with septic shock. Interventions:None. Measurements and Main Results:We stratified subjects into three mortality risk categories (low, intermediate, and high) using a validated biomarker-based stratification tool. Within each category, we assessed three fluid balance variables: total fluid intake/kg/d during the first 24 hours, percent positive fluid balance during the first 24 hours, and cumulative percent positive fluid balance up to 7 days. We used logistic regression to estimate the effect of fluid balance on the odds of 28-day mortality, and on complicated course, which we defined as either death within 28 days or persistence of two or more organ failures at 7 days. There were 40 deaths, and 91 subjects had a complicated course. Increased cumulative percent positive fluid balance was associated with mortality in the low-risk cohort (n = 204; odds ratio, 1.035; 95% CI, 1.004–1.066) but not in the intermediate- and high-risk cohorts. No other associations with mortality were observed. Fluid intake, percent positive fluid balance in the first 24 hours, and cumulative percent positive fluid balance were all associated with increased odds of a complicated course in the low-risk cohort but not in the intermediate- and high-risk cohorts. Conclusions:When stratified for mortality risk, increased fluid intake and positive fluid balance after ICU admission are associated with worse outcomes in pediatric septic shock patients with a low initial mortality risk but not in patients at moderate or high mortality risk.

Mitochondrial dysfunction in peripheral blood mononuclear cells in pediatric septic shock.

Objectives: Mitochondrial dysfunction in peripheral blood mononuclear cells has been linked to immune dysregulation and organ failure in adult sepsis, but pediatric data are limited. We hypothesized that pediatric septic shock patients exhibit mitochondrial dysfunction within peripheral blood mononuclear cells which in turn correlates with global organ injury. Design: Prospective observational study. Setting: Academic PICU. Patients: Thirteen pediatric patients with septic shock and greater than or equal to two organ failures and 11 PICU controls without sepsis or organ failure. Interventions: Ex vivo measurements of mitochondrial oxygen consumption and membrane potential (&Dgr;&PSgr;m) were performed in intact peripheral blood mononuclear cells on day 1–2 and day 5–7 of septic illness and in controls. The Pediatric Logistic Organ Dysfunction score, inotrope score, and organ failure–free days were determined from medical records. Measurements and Main Results: Spare respiratory capacity, an index of bioenergetic reserve, was lower in septic peripheral blood mononuclear cells on day 1–2 (median, 1.81; interquartile range, 0.52–2.09 pmol O2/s/106 cells) compared with controls (5.55; 2.80–7.21; p = 0.03). Spare respiratory capacity normalized by day 5–7. Patients with sepsis on day 1–2 exhibited a higher ratio of LEAK to maximal respiration than controls (17% vs < 1%; p = 0.047) with normalization by day 5–7 (1%; p = 0.008), suggesting mitochondrial uncoupling early in sepsis. However, septic peripheral blood mononuclear cells exhibited no differences in basal or adenosine triphosphate–linked oxygen consumption or &Dgr;&PSgr;m. Oxygen consumption did not correlate with Pediatric Logistic Organ Dysfunction score, inotrope score, or organ failure–free days (all p > 0.05). Although there was a weak overall association between &Dgr;&PSgr;m on day 1–2 and organ failure–free days (Spearman &rgr; = 0.56, p = 0.06), patients with sepsis with normal organ function by day 7 exhibited higher &Dgr;&PSgr;m on day 1–2 compared with patients with organ failure for more than 7 days (p = 0.04). Conclusions: Mitochondrial dysfunction was present in peripheral blood mononuclear cells in pediatric sepsis, evidenced by decreased bioenergetic reserve and increased uncoupling. Mitochondrial membrane potential, but not respiration, was associated with duration of organ injury.