Sepsis Biomarkers Daniel B. Ambrus, MD MSc Assistant Professor, Department of Hospital Medicine SLAM Sepsis Symposium, October 31st, 2018

Disclosures I have no actual or potential conflicts of interest with regard to this program/presentation I am not an expert in sepsis or molecular biology I did my best to do my homework!

Objectives To establish the added value of biomarkers to clinical assessment of the septic patient To review the various available biomarkers in sepsis, their performance and their current role To identify barriers to biomarker implementation and look to the future

Sepsis Pathophysiology Complex, heterogeneous process with multiple contributing factors Gomes AP, et al. (2016) Pro-Inflammatory Cytokines in Sepsis: Biological Studies and Prospects From In Silico Research. Biol Syst Open Access 5:158

What is a Biomarker? “…a characteristic that is objectively measured and evaluated as an indicator of normal biological processes, pathogenic processes, or pharmacologic responses to a therapeutic intervention” -Group BDW. Biomarkers and surrogate endpoints: preferred definitions and conceptual framework. Clinical Pharmacology and Therapeutics. 2001; 37:2290–2298.

Types of Biomarkers Diagnostic: Establishes a diagnosis that enables a treatment decision rapidly & inexpensively Monitoring: Measures response to intervention, enabling titration of treatment dose or duration Surrogate: Not itself a measure of a patient-centered outcome but reliably predicts a clinical outcome Prognostic: Identifies subgroups who are more likely to benefit from treatment or be harmed Marshall JC, Reinhart K, International Sepsis F. Biomarkers of sepsis. Crit Care Med. 2009; 37(7): 2290–2298

Why Biomarkers? Diagnostic: Need better tools to rule sepsis in or out SIRS criteria were mainstay since 2001 Most hospitalized patients experience SIRS without sepsis 1 in 8 patients who develop severe sepsis will not have 2/4 SIRS criteria upon first contact Churpek et al. Am J Respir Crit Care Med 2015 Oct 15; 192(8): 958-964

Why Biomarkers? Monitoring: Need to predict favorable response to antibiotics How do we know which antibiotic to choose? Up to 40% of patients admitted to intensive care units with a diagnosis of sepsis do not have an infection 2016 SSC guideline requires broad spectrum antibiotic in less than one hour for all patients with suspected sepsis Stewardship concerns IDSA did not endorse 2016 Surviving Sepsis Campaign guidelines in part over these concerns IDSA Sepsis Task Force. Clinical Infectious Diseases, Volume 66, Issue 10, 2 May 2018, Pages 1631–1635

ROC and AUROC AUROC values: .90-1 = excellent (A) .80-.90 = good (B) .70-.80 = fair (C) .60-.70 = poor (D) .50-.60 = fail (F)

Why Biomarkers? Prognostic: Need to know who is at highest risk for and how to identify them at the first point of contact Ability to discriminate in- hospital mortality prior to ICU admission by clinical criteria alone: ≥2 qSOFA: AUROC= 0.73; 95% CI, 0.65–0.81 2/4 SIRS: AUROC= 0.57; 95% CI, 0.48–0.66 Finkelsztein, EJ et al. Crit Care 2017; 21, 73

What About Lactate? Diagnostic value: Poor sensitivity & specificity; complex physiology during sepsis is poorly understood Monitoring value: As part of SEP-1, should be measured and repeated until <2 mmol/L Prognostic value: Universally accepted as a marker for worse outcomes during sepsis

Name ? Diagnostic Marker? Monitoring Marker? Surrogate Marker? Jacobs et al. Expert Rev Anti Infect Ther. 2016 October ; 14(10): 929–941 Name Diagnostic Marker? Monitoring Marker? Surrogate Marker? Prognostic Marker? Lactic Acid ✖ ✔ Pro-calcitonin ± Interleukin-8 Interleukin-27 Presepsin Cell Free DNA ? Neutrophil CD64 SeptiCyte

Name Available at UMass FDA Approval Turnaround Time Cost Per Item Lactic Acid Yes 1h $64 Pro-calcitonin N/A Up to 5d Interleukin-8 No Interleukin-27 Presepsin Cell Free DNA Neutrophil CD64 SeptiCyte Paula Styles 774-442-9511

We Need Something More “The task force recognized that sepsis is a syndrome without, at present, a validated criterion standard diagnostic test... The task force determined that there was an important need for features that can be identified and measured in individual patients.” -Singer M, et al. The third international consensus definitions for sepsis and septic shock (sepsis-3). JAMA. 2016; 315(8):801–810.

Procalcitonin: Vital Statistics Quantitative ?Diagnostic, Monitoring, Prognostic Normally made in small amounts by thyroid, infection causes it to be expressed by other tissues Levels rise within 4-6 hours of infection and fall similarly quickly upon resolution of infection Peaks after 12-48h

Procalcitonin: Diagnostic Value May add diagnostic value to clinical assessment, not endorsed in guidelines Meta-analysis by Tang et al., Lancet 2007: Ability to discriminate sepsis from non-inflammatory SIRS: AUC =0.78 Authors concluded this was poor performance Meta-analysis by Wacker et al., Lancet 2013: Ability to discriminate sepsis from non-inflammatory SIRS: AUC =0.85 Authors concluded this was good performance Data does not support starting antibiotics based on PCT levels Randomized trial by Jensen et al., Crit Care Med 2011: Procalcitonin guided antibiotic escalation led to worse outcomes

Procalcitonin: Monitoring Value Algorithms in clinical trials have been shown to reduce antibiotic duration and even mortality 2016 SSC: “Procalcitonin levels can support decision to shorten the duration of antibiotics in patients with known sepsis, or stop antibiotics in patients with limited evidence for sepsis.” IDSA: “Our interpretation of the literature is that …procalcitonin guidance for duration of antibiotic therapy is feasible and safe in critically ill patients with infections.” Areas of uncertainty: Possible “prompting effect” in clinical trials Heterogeneity between studies and among algorithms used for de-escalation No guidance on how to operationalize in day-to-day practice

Procalcitonin: Prognostic Value Consistent association between higher levels of PCT and worse outcomes including end-organ damage, mortality, etc. Boussky, et al.: 2005 prospective cohort of critically ill patients with pneumonia Those who died in the ICU had mean initial PCT of 5.6 vs. 1.5 in those who survived Wanner, et al.: 2000 serial assessment of PCT levels in trauma patients Patients eventually diagnosed with severe MODS had initial mean PCT 5.7 vs. 1.1 for patients with uneventful recovery

Name ? Diagnostic Marker? Monitoring Marker? Surrogate Marker? Jacobs et al. Expert Rev Anti Infect Ther. 2016 October ; 14(10): 929–941 Name Diagnostic Marker? Monitoring Marker? Surrogate Marker? Prognostic Marker? Lactic Acid ✖ ✔ Pro-calcitonin ± Interleukin-8 Interleukin-27 Presepsin Cell Free DNA ? Neutrophil CD64 SeptiCyte

Name Available at UMass FDA Approval Turnaround Time Cost Per Item Lactic Acid Yes 1h $14-47 Pro-calcitonin 12h-5d $25 Interleukin-8 No Interleukin-27 Presepsin Cell Free DNA Neutrophil CD64 SeptiCyte Paula Styles 774-442-9511

Interleukin-8 (IL-8) What it is: Chemokine produced by macrophages to mobilize neutrophils Expression is upregulated among patients with septic shock within 24 hours (best validated in pediatric) Implication as prognostic marker Pediatric: high IL-8 associated with 10 fold mortality risk Adult: high IL-8 AUROC for 28-day mortality was 0.74

Name ? Diagnostic Marker? Monitoring Marker? Surrogate Marker? Jacobs et al. Expert Rev Anti Infect Ther. 2016 October ; 14(10): 929–941 Name Diagnostic Marker? Monitoring Marker? Surrogate Marker? Prognostic Marker? Lactic Acid ✖ ✔ Pro-calcitonin ± Interleukin-8 Interleukin-27 Presepsin Cell Free DNA ? Neutrophil CD64 SeptiCyte

Name Available at UMass FDA Approval Turnaround Time Cost Per Item Lactic Acid Yes 1h $14-47 Pro-calcitonin 12h-5d $25 Interleukin-8 No Research Only 1-4d ? Interleukin-27 Presepsin Cell Free DNA Neutrophil CD64 SeptiCyte Paula Styles 774-442-9511

Interleukin-27 (IL-27): Vital Statistics Cytokine dimer made of IL-27.p28 gene + Epstein-Barr virus induced gene (EBI-3) subunits Quantitative Pro and anti-inflammatory properties Expression due to inflammation is robust during early childhood, declining into adulthood Diagnostic implications

Interleukin-27 (IL-27): Diagnostic in Pediatric Developed as a diagnostic marker using gene mapping of sepsis in children Good correlation with sepsis in pediatric population (AUROC 0.64-0.81 in various studies/populations) Poorer performance in adults (AUROC ~0.68) Possibly due to declining expression of EBI-3 in adulthood Improved performance in non-pulmonary origin sepsis

Name ? Diagnostic Marker? Monitoring Marker? Surrogate Marker? Jacobs et al. Expert Rev Anti Infect Ther. 2016 October ; 14(10): 929–941 Name Diagnostic Marker? Monitoring Marker? Surrogate Marker? Prognostic Marker? Lactic Acid ✖ ✔ Pro-calcitonin ± Interleukin-8 Interleukin-27 Presepsin Cell Free DNA ? Neutrophil CD64 SeptiCyte

Name Available at UMass FDA Approval Turnaround Time Cost Per Item Lactic Acid Yes 1h $14-47 Pro-calcitonin 12h-5d $25 Interleukin-8 No Research Only 1-4d ? Interleukin-27 Presepsin Cell Free DNA Neutrophil CD64 SeptiCyte Paula Styles 774-442-9511

Presepsin (sCD14-ST): Vital Statistics What it is: Circulating fragment of macrophage surface receptor CD-14, cleaved by proteases in response to inflammation Pharmacodynamics: Lab models demonstrate detection within 2h of insult, peak levels within 3h Results within 1-4 hours depending on assay used Lab notes: Quantitative Clinical value: Diagnostic, monitoring and prognostic implications

Presepsin (sCD14-ST) Diagnostic value: Excellent ability to discriminate between SIRS and Sepsis (AUROC 0.81-0.89) Performance remained high 2-3 days after sepsis onset Monitoring & Prognostic value: Increasing levels are highly correlated with illness severity (APACHE-III and SOFA scores)

Name ? Diagnostic Marker? Monitoring Marker? Surrogate Marker? Jacobs et al. Expert Rev Anti Infect Ther. 2016 October ; 14(10): 929–941 Name Diagnostic Marker? Monitoring Marker? Surrogate Marker? Prognostic Marker? Lactic Acid ✖ ✔ Pro-calcitonin ± Interleukin-8 Interleukin-27 Presepsin Cell Free DNA ? Neutrophil CD64 SeptiCyte

Name Available at UMass FDA Approval Turnaround Time Cost Per Item Lactic Acid Yes 1h $14-47 Pro-calcitonin 12h-5d $25 Interleukin-8 No Research Only ? Interleukin-27 1-4d $10 Presepsin 1-4h $6 Cell Free DNA Neutrophil CD64 SeptiCyte Paula Styles 774-442-9511

Cell Free DNA (cfDNA) What it is: Product of cell apoptosis. Normally found in low levels but high cell turnover in sepsis Pharmacodynamics: Detectable within 6 hours, peaks after 24 hours Lab notes: Quantitative, usually requires time consuming spectrophotometer or PCR, but new point of care assay show promise Potential uses: Mainly prognostic implications

cfDNA: Clinical Value Diagnostic value: Two small studies concluded AUROC 0.95-0.99 to discriminate sepsis vs. inflammation Prognostic value: Significantly higher levels in non- survivors, AUROC for mortality 0.81

Name ? Diagnostic Marker? Monitoring Marker? Surrogate Marker? Jacobs et al. Expert Rev Anti Infect Ther. 2016 October ; 14(10): 929–941 Name Diagnostic Marker? Monitoring Marker? Surrogate Marker? Prognostic Marker? Lactic Acid ✖ ✔ Pro-calcitonin ± Interleukin-8 Interleukin-27 Presepsin Cell Free DNA ? Neutrophil CD64 SeptiCyte

Name Available at UMass FDA Approval Turnaround Time Cost Per Item Lactic Acid Yes 1h $14-47 Pro-calcitonin 12h-5d $25 Interleukin-8 No Research Only ? Interleukin-27 1-4d $10 Presepsin 1-4h $6 Cell Free DNA Variable Neutrophil CD64 SeptiCyte Paula Styles 774-442-9511

Neutrophil CD64 (nCD64): Vital Statistics What it is: Monocyte surface receptor, marked upregulation after exposure to pathogen Pharmacodynamics: Levels rise within 2 hours, remain elevated for a few days after exposure Lab notes: Quantitative, requires flow cytometry, ~10$ per test Potential Uses: Diagnostic, Monitoring and Prognostic implications

nCD64: Clinical Applications Diagnostic value: Among adults, ability to identify bacterial infection/sepsis is excellent (AUROC ~0.95) nCD64 index proposed in one study Index >1.19 had ST 94%, SP 88% for infection Index < 1.19 associated with 100% NPV for positive blood cultures Monitoring value: Persistent elevation of nCD64 in pts who receive ineffective antibiotic therapy Prognostic value: Expression associated with clinical markers of severity and worse in-hospital mortality

Name ? Diagnostic Marker? Monitoring Marker? Surrogate Marker? Jacobs et al. Expert Rev Anti Infect Ther. 2016 October ; 14(10): 929–941 Name Diagnostic Marker? Monitoring Marker? Surrogate Marker? Prognostic Marker? Lactic Acid ✖ ✔ Pro-calcitonin ± Interleukin-8 Interleukin-27 Presepsin Cell Free DNA ? Neutrophil CD64 SeptiCyte

Name Available at UMass FDA Approval Turnaround Time Cost Per Item Lactic Acid Yes 1h $14-47 Pro-calcitonin 12h-5d $25 Interleukin-8 No Research Only ? Interleukin-27 1-4d $10 Presepsin 1-4h $6 Cell Free DNA Variable Neutrophil CD64 SeptiCyte Paula Styles 774-442-9511

SeptiCyte: Vital Statistics Tests whole blood expression of four genes: CEACAM4, LAMP1,PLAC8, PLA2G7 Quantitative, reported in bands 1-4 Approved by FDA April 6th, 2017 Diagnostic implications AUROC for SIRS vs Sepsis 0.82-0.88

Name ? Diagnostic Marker? Monitoring Marker? Surrogate Marker? Jacobs et al. Expert Rev Anti Infect Ther. 2016 October ; 14(10): 929–941 Name Diagnostic Marker? Monitoring Marker? Surrogate Marker? Prognostic Marker? Lactic Acid ✖ ✔ Pro-calcitonin ± Interleukin-8 Interleukin-27 Presepsin Cell Free DNA ? Neutrophil CD64 SeptiCyte

Name Available at UMass FDA Approval Turnaround Time Cost Per Item Lactic Acid Yes 1h $14-47 Pro-calcitonin 12h-5d $25 Interleukin-8 No Research Only ? Interleukin-27 1-4d $10 Presepsin 1-4h $6 Cell Free DNA Variable Neutrophil CD64 SeptiCyte <24h Paula Styles 774-442-9511

What the Future Holds SeptiCyte NCD64 IL-8 Presepsin IL-27 Lactic Acid Procalcitonin NCD64 IL-8 Presepsin IL-27 SeptiCyte Lactic Acid Cell Free DNA

Thank You Michelle Kelly Sepsis Committee Paula Stiles and laboratory staff