Biomarkers & Imaging John E. Eaton MD Division of Gastroenterology and Hepatology Mayo Clinic College of Medicine and Science Rochester MN USA

Objectives Define the term “Biomarker” Implications of biomarkers for individual patients & drug development Overview of select non-radiographic & magnetic resonance imaging based biomarkers used in clinical practice *Did not include information about cholangiocarcinoma biomarkers but happy to discuss in Q&A if questions

Biomarkers Definition (FDA) An objective measured indicator of normal biology, pathologic process or response to therapy

Importance of Biomarkers in PSC Clinical practice Diagnostic & prognostic Necessity for clinical trials & drug approval Biomarkers as surrogate endpoints Used in clinical trials as substitute for a direct measure of how a patient feels, functions or survives Useful when disease is rare and clinical events uncommon

Predictive Biomarkers & Surrogate Endpoints Medicines Crystal Ball…ideally ∆ Surrogate endpoint (predictive biomarker) Intervention Group A PSC patients ∆ Clinical Outcome Ex., liver transplant No ∆ Surrogate endpoint (predictive biomarker) No intervention Group B PSC patients No ∆ Clinical Outcome Ex., liver transplant Time

Potential Diagnostic & Prognostic Biomarkers Hot area for research evolving rapidly! Cholestasis Alkaline phosphatase GGT Total bilirubin Serum bile acids C4 Prognostic scores (PREsTo, MELD, Mayo PSC Risk, UK PSC Risk) Cholangiogram MRCP based (ANALI, MRCP+) ERCP based (Amsterdam score) Fibrosis & Portal HTN Histology Elastography Spleen Length ELF score APRI proC3 Prognostic scores (PREsTo, Mayo PSC Risk, UK PSC Risk) Immune System Histology MRI based assessment of inflammation VAP 1 Cytokines

Diagnostic & Prognostic Biomarkers in Clinical Practice Cholestasis Alkaline phosphatase GGT Total bilirubin Serum bile acids C4 Prognostic scores (PREsTo) MELD, Mayo PSC Risk, UK PSC Risk Cholangiogram MRCP based (ANALI, MRCP+) ERCP based (Amsterdam score) Fibrosis & Portal HTN Histology Elastography Spleen Length ELF score APRI proC3 Prognostic scores (PREsTo), Mayo PSC Risk, UK PSC Risk Immune System Histology MRI based assessment of inflammation

Serum Alkaline Phosphatase (SAP) Enzyme in multiple organs Liver, intestine, bone, placenta, kidney Normal or < 1.5 x ULN improved outcomes After 7 years 15% normal SAP versus 35% abnormal SAP developed serious complication Used as primary or secondary surrogate endpoint in most PSC trials I would also look at this as 65% of patients with an abnormal alkaline phosphatase DON’T have a bad outcome after 7 years…we can do better at predicting outcomes Al Mamari S, et al. J Hepatol 2013 Stanich P, et al. Dig Liver Dis 2011

SAP alone is suboptimal biomarker Lacks specificity 60% of patients with SAP >1.5 x ULN no liver related complications over 10 years Normal SAP common Rate of normalizing 5% per year 55% re-develop an abnormal SAP within 2 years Wide individual fluctuations SAP varied by 12% during 96 week simtuzumab trial Changes not associated with outcomes Reasons for these fluctuations are typically not apparent. Al Mamari S, et al. J Hepatol 2013 Stanich P, et al. Dig Liver Dis 2011 Eaton JE, et al. AASLD submitted 2019 Trivedi PJ, EASL 2019

PSC Risk Estimate Tool (PREsTo) Novel model created using artificial intelligence 9 variables Eaton JE, et al. Hepatology 2018

PREsTo Accurately Predicts Hepatic Decompensation Eaton JE, et al. Hepatology 2018

PREsTo In Action https://rtools.mayo.edu/PRESTO_calculator/ Person 2 Age (years) 20 45 SAP x ULN 1.3 1.7 AST 40 90 Total Bilirubin 1.0 3.0 Albumin 4.0 3.5 Sodium 140 136 Hemoglobin 14.5 12.5 Platelets x109 300 180 PSC duration (years) 2 15 70% Person 2 Person 1 3% https://rtools.mayo.edu/PRESTO_calculator/

Role of Magnetic Resonance Imaging Studies Diagnosis of PSC Monitoring for complications ERCP triage & roadmap for endoscopist Measurement of liver stiffness (magnetic resonance elastography, MRE)

MRCP/MRE Picture also illustrates that PSC is a patchy disease that does not impact the liver and bile ducts in a uniform manner. T2, DWI, Arterial enhancement and delayed phase images and MRE MRCP (A) showing multiple strictures including R. posterior duct stricture (arrow). Corresponding sequences showing hyperintensity due to inflammation/fibrosis with focal ↑ liver stiffness (MRE, F) with mild atrophy and compensatory left lobe hypertrophy.

MRI/MRCP Downsides MRI/MRCP intolerance (relatively uncommon) Cost Claustrophobia, incompatible devices Cost Quality & access may vary Gadolinium contrast agent Helpful if concerned for malignancy but not mandatory Gadolinium may deposit in tissue after repeated exposure No adverse clinical effects in humans/animals to date Selective use in gadolinium Avoid in renal failure

Elastography Magnetic Resonance Elastography & Transient elastography (Fibroscan) Conceptual Framework Speed at which vibration wave travels through tissue is related to tissue stiffness. Tissue stiffness=surrogate for fibrosis Nonfibrotic causes of increased stiffness Acute inflammation Acute biliary obstruction Example, “dominant strictures” in PSC Heart failure

Magnetic Resonance Elastography (MRE) -90 +90 Displacement (mm) Shear Stiffness (kPa)) 10 4 6 8 2 10 +90 Reproducible Predicts fibrosis stage Predicts outcomes: Low risk <4.5 kPa Medium 4.5-6.0 kPa Higher risk > 6.0 kPa 4 Displacement (mm) -90 Imaging time: 11-16s/slice Active Driver Acoustic waves at 60Hz Eaton JE, et al. J Gastroenterol Hepatol 2016 Eaton JE, et al. submitted 2019

Fibroscan (transient elastography) Accurately predicts stage of fibrosis Associated with outcomes in PSC Corpechot C, et al. Gastroenterology 2014

MRE versus Fibroscan (transient elastography) Lower failure rate Samples larger volume Can detect complications When MRCP performed no added cost or much time Widely available Done at bedside Cheaper & easier if MRCP not required MRE Fibroscan

Appearance of bile ducts, liver & stiffness important MRCP prognostic score (ANALI) + Elastography Components of ANALI score: Intrahepatic bile duct dilation “Dysmorphy” (i.e., atrophy, cirrhotic appearing liver) Presence of portal hypertension % adverse outcome LS=liver stiffness Cazzagon N, et al. EASL 2019

Quantitative Biliary Metrics Sophisticated & elegant appearing software that measures aspects of the biliary tree and individual duct segments. Unresolved questions: is this technology reproducible, does it provide prognostic information, are changes over time associated with changes in disease course Areas of uncertainty Prognostic value Reproducibility & accuracy

Summary Biomarkers are an objective measurement of normal or disease process Accurate biomarkers that can serve as surrogate endpoints in clinical trials essential step for drug development & approval Diagnostic & prognostic biomarkers useful for routine care Key biomarkers to be familiar with as patients are liver tests (examples, alkaline phosphatase, total bilirubin), prognostic scores (example, PREsTo), MRI/MRCP & elastography