Bioartificial Human Liver Therapy Trial Progressing

Vital Therapies Enrolls First Patients in Expansion of its U.S. Clinical Trial in Europe

SAN DIEGO, June 9, 2010 - Vital Therapies, Inc., (VTI) is pleased to announce that the first two
subjects have been enrolled at King's College Hospital in London in the
expansion of its SILVER (Stabilization In LiVER failure) clinical trial in
Europe. The trial is evaluating whether VTI's biological cellular therapy
product, ELAD(R), can prevent deterioration of liver function and improve the
survival of patients with acute-on-chronic liver failure (ACLF).

The SILVER trial is an open label, multi center, controlled, randomized
trial. To date, 29 subjects have been enrolled at 11 U.S. sites and one U.K.
site at King's College Hospital, a major European centre for the treatment of
complex liver disease. Several other sites will soon be open for enrollment
in the U.K., Denmark and Saudi Arabia. More than 20 sites should eventually
enroll a total of 80 or more patients in a 1:1 treated-to-control ratio. If
successful, the resulting data will provide the basis for a Biological
License Application (BLA) in the U.S., a Marketing Approval Application (MAA)
in Europe, and a marketing approval application in Saudi Arabia. For a full
listing of clinical trial sites and further information on the trial, please
go to www.clinicaltrials.gov.

The SILVER protocol enrolls subjects with chronic liver disease who have
been hospitalized as a result of an event, such as an infection or an episode
of bleeding, which has caused deterioration of their liver function
(acute-on-chronic liver failure, ACLF). The trial is designed to explore
whether the use of ELAD in this setting can prevent continued deterioration
of liver function, called progression, and thus improve survival. The trial
design uses a well-established measure of liver function called the MELD
score to define the status of liver function. Treatment with ELAD, along with
standard of care, is compared with standard of care alone. The time to either
death or deterioration of liver function by a prespecified amount is
measured. It is postulated that the use of ELAD may extend the time to
progression and improve survival in this rapidly progressing patient
population.

ELAD is a biologic liver support system using a proprietary line of
allogeneic human liver cells originally derived from a human liver tumor and
refined by several leading cell experts. The cells are stable, immortal, can
be grown in unlimited quantities and retain their hepatocyte (liver cell)
characteristics. About one pound of cells is used for each treatment. The
cells are grown in specially designed cartridges at VTI's plant in San Diego,
transported to the hospital and used to treat the patient's plasma outside
the body for up to ten days.

At the recent European Association for the Study of the Liver (EASL)
meeting in Vienna a symposium sponsored in part by Vital Therapies addressed
the use of liver support systems in ACLF. Michael Millis, M.D., Head of Liver
Transplantation at the University of Chicago presented results of earlier
clinical trials with ELAD including Phase I/II data in patients with acute
liver failure. He also presented results of a randomized, controlled trial of
ELAD carried out in China in 69 patients with ACLF. The China data confirmed
previously reported preliminary data in 60 patients, which showed that ELAD
significantly improved transplant free survival in subjects with ACLF
compared with standard of care alone, without unforeseen safety issues.

About Vital Therapies, Inc.

Vital Therapies, Inc. (VTI) is based in San Diego, California, with a
wholly owned subsidiary in Beijing, China. VTI is developing the first human
liver cell-based ELAD Extracorporeal Liver Assist System. ELAD could provide
support for patients with severe liver failure by processing toxins and
synthesizing proteins and metabolites that are key products of normal human
liver function. ELAD is in investigational clinical trials and VTI completed
a pivotal trial and filed for market approval in China in September 2007. For
additional information visit www.vitaltherapies.com or contact Terry
Winters, PhD, CEO, Vital Therapies at +1-858-673-6840. ELAD is a trademark of
Vital Therapies, Inc.

About King's College Hospital, Liver Unit

King's College Hospital is home to one of the largest liver units in
Europe, performing over 200 liver transplants every year. It is also a major
centre for the treatment of complex acute and chronic liver disease, as well
as viral hepatitis and pancreato-biliary. For additional information visit
www.kch.nhs.uk . King's College Hospital, Denmark Hill, London,
England. +44-(0)20-3299 9000

Terry Winters, PhD, CEO of Vital Therapies, +1-858-673-6840, or King's College Hospital, +44-(0)20-3299 9000