Vital Therapies Hybrid Liver

Liver Physiology Most metabolically complex organ in the entire body Largest internal organ Responsible for over 500 discrete functions Primary functions include: Detoxification Protein synthesis Production of biochemicals Other functions: liver produces albumin and is a major osmolar component of blood serum

Highly specialized tissue. Composed of two basic cell types: Karat parenchymal cells (hepatic cells) – 80% of liver volume Non-parenchymal cells – 6.5% of liver volume Hepatic cells are responsible for liver function

Types of Disease Most liver diseases are chronic Common types include: Hepatitis A, B, C, D, E Alcohol damage Fatty liver Cirrhosis (final stage of chronic liver disease) Cancer Drug damage Damage to hepatocytes Two scenarios: Mild and reversible Sustained or more severe

Development of ALF When a liver injury is sustained or more severe, regeneration may be incomplete or healing may occur with the development of negative consequences that can lead to acute liver failure

ALF Common signs and symptoms: Cerebral edema (can lead to a coma) Coagulopathy (impairs blood clotting) Renal failure Hypoglycaemia (results from diminished glucose in the blood) Testing for ALF Testing positive for prolonged prothrombin time Altered sensorium

The prothrombin time (PT) and its derived measures of prothrombin ratio (PR) and international normalized ratio (INR) are measures of the extrinsic pathway of coagulation. They are used to determine the clotting tendency of blood, in the measure of warfarin dosage, liver damage, and vitamin K status

Today’s Treatments Currently, there are a limited number of treatments/therapies available to patients with ALF Two main options: Liver Dialysis (supportive treatment) Primarily used as a bridge to transport Cannot support a patient for an extended period of time Transplantation Ultimate goal Limited supply “According to the United Network for Organ Sharing, there were 6,000 liver transplants performed in 2006 however there were more than 16,000 patients on the waiting list. Consequently, each year only about one-third of the people who need a donor liver will receive one, and many patients die while waiting.”

Treatments Compared Liver Transplant Pros: Best way to treat ALF High survival rates Cons: Limited supply Reduced clotting factors Immunosuppressants increase risk for infection Possibility of host rejection Bio-artificial Liver (enhanced liver dialysis) Extends the patient’s life expectancy until transplant is made available Better hepatocyte regeneration therapy Temporary (bridge to transport) Not long-term

Treatments in Progress Liver Dialysis Unit (formerly BioLogic – DT) HemoTherapies, uses noncellular charcoal Molecular Absorbent Recycling System (MARS®) Teraklin, uses human albumin Extracorporeal Liver Assist Device (ELAD®) Vitagen, uses immortalized human hepatocytes HepatAssist 2000 system Circe Biomedical, uses porcine hepatocytes Bioartificial Liver Support System (BLSS®) Excorp Medical, Inc., uses primary porcine hepatocytes LIVERX2000 system Algenix, Inc., uses primary porcine hepatocytes Modular Extracorporeal Liver System (MELS®) Charite Virchow Clinic-Berlin, uses human hepatocytes

ELAD versus the Market The key characteristic of the ELAD device is its ability to stabilize liver function in patients with life-threatening, acute liver failure by processing toxins and synthesizing proteins that are key products of normal human liver function The key to the ELAD system is the proprietary C3A human hepatocyte cell line. This is an immortal cell line that is grown in ELAD cartridges. The C3A cell line performs biochemical functions characteristic of human hepatocytes and can synthesize serum proteins. These cells synthesize a wide variety of proteins, such as albumin, an indicator of hepatocyte function and a convenient marker of cell viability and function In vitro assays demonstrated that the C3A cell line performs biochemical functions characteristic of human hepatocytes, while in vivo experiments evaluated the safety of the entire ELAD System, as well as function of the C3A cells C3A cell line vs. Porcine cell line C3A cell line is a sub clone of regular liver cells (hepatocytes) Porcine cells are xenogeneic and in order for them to be used in a bio-artificial liver device they need to be incubated in complement inactive serum/plasma

C3A Cell Line The fibers, made of a semi-permeable membrane, permit passage, from the C3A cells to the patient's ultrafiltrate, of macromolecules and other cellular products such as albumin, Factor V, transferrin, antithrombin III, C3 complement, Î¬-1-antitrypsin, Î¬-fetoprotein, and others. The fibers also simultaneously permit passage of toxins and such nutrients as glucose and oxygen from the ultrafiltrate to the C3A cells. After circulation through the cartridges, the ultrafiltrate then flows through filters prior to recombining with the cellular components of the patient's blood and returning to the patient. This circulation is maintained continuously utilizing the same set of cartridges for the duration of ELAD therapy

Expected Improvements Post-Op Various trials in patients with different stages/causes of acute hepatic failure US/UK Pilot Studies in Fulminant Hepatic Failure Improved overall survival regardless of transplantation status Significant improvement in bridge-to-transplant/recovery with intact native liver China Trial: Acute Liver Failure, 70% infected with hepatitis B Significant improvement in transplant-free survival Median survival for control: 37 days No median transplant-free survival among ELAD All survived beyond 3 year follow-up Phase IIB Acute Alcoholic Hepatitis Trial Control Median survival: 65 days ELAD Median survival: 100+ days Improved mental status

Expected Complications Post-Op No current short-term safety problems Clinical trial evaluating potential acute medical complications post-therapy Hemodynamic instability, complement activation, and vital organ deterioration Porcine-hepatocyte BAL: noted bleeding complications, hemodynamic instability Complement activation Previous issues with system clotting More aggressive heparin treatment during therapy 1 report of hypotension during therapy Corrected/reversed 1 report of tachypnea, tachycardia, and pyrexia during therapy Stopped post-hemoperfusion Minor complications solved after modifying ELAD treatment Switch from whole blood to ultra-filtered blood Highly cirrhotic with acute-on-chronic hepatitis diagnosis study No suggested benefit for those with extensive cirrhosis

ELAD Limitations Hepatocyte acquisition Best delivery, design, and components?

Future Developments Implantable devices Vianney et al. study with allogeneic rat hepatocytes Hollow fiber peritoneal implant Longer-term solutions

Works Cited http://biomed.brown.edu/Courses/BI108/BI108_1999_Groups/Liver_Team/Liver.html#functional http://biomed.brown.edu/Courses/BI108/BI108_2002_Groups/liver/webpage/vitagenpg.htm http://clinicaltrials.gov/ct2/show/NCT00973817?term=ELAD&rank=4 http://medcitynews.com/2012/11/supported-by-an-86-million-round-first-bio-artificial-liver-moves-toward-pivotal-trials/ http://web.mit.edu/lmrt/publications/2001/Allen2001_Hepat.pdf http://www.atcc.org/products/all/CRL-10741.aspx#85786B46AA23451B94BC5D45200673F7 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1356396/ http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1774070/ http://www.vitaltherapies.com/elad_assests/elad_simulation.html http://www.vitaltherapies.com/technology.html http://www.vitaltherapies.com/pdf/04_17_2013_Fact_Sheet_Clinicians_JG.pdf