Virobay and LEO Pharma Initiate a Phase 1 Trial of VBY-891, a Compound Intended for Oral Treatment of Psoriasis

Menlo Park, California And Ballerup, Denmark (ots/PRNewswire) -

Virobay, Inc. and LEO Pharma A/S today announced that their
collaboration on the development of an oral treatment for psoriasis
has reached an important milestone as Virobay has now initiated a
Phase 1 clinical trial of VBY-891 - a selective cathepsin S
inhibitor.

(Logo: http://photos.prnewswire.com/prnh/20130221/595427 )

The first Phase 1 trial of VBY-891 is a double-blind, randomized,
placebo-controlled study designed to evaluate the safety,
tolerability, pharmacokinetics and pharmacodynamics of single and
multiple escalating doses of VBY-891 in healthy adults.

"The initiation of this Phase 1 trial represents a significant
development objective for Virobay's collaboration with LEO Pharma,"
stated Robert Booth, Ph.D., Chief Executive Officer of Virobay.
"Virobay has plans to initiate clinical studies with additional
cathepsin inhibitors during 2013 as we seek to develop new therapies
for underserved diseases. Published prelinical data suggest that
cathepsin S inhibition may provide a therapeutic benefit in patients
with dermatological disorders such as psoriasis. In addition, our own
preclinical data with selective cathepsin S inhibitors has
demonstrated efficacy in models of both psoriasis and atopic
dermatitis," stated Robert Booth. "We look forward to assessing the
data from these Phase 1 trials, which will incorporate the evaluation
of several biomarkers, to guide our Phase 2 clinical development
plans for VBY-891."

"Reaching this important milestone in our collaboration with
Virobay brings us one step closer to provide an oral treatment for
psoriasis patients. We believe that VBY-891 has the potential to
provide an oral treatment that may alleviate symptoms of psoriasis.
LEO Pharma strives to constantly expand and improve treatment options
for patients and this is an important example of our commitment to
meeting patient needs. To the best of our knowledge, the VBY-891
compound has the potential to be the first in class on the market,"
said Kim Kjoller, Senior Vice President, Global Development, LEO
Pharma.

Background

About Cathepsin S and VBY-891

Cathepsin S is a member of the cysteine protease family of
cathepsin inhibitors that catalyzes the final proteolytic step in the
processing of invariant chain in specific antigen presenting cells.
This step is essential in the maturation and loading of MHC Class II
with antigenic peptides and subsequent activation of CD4+ T cells.
Continuous presentation of antigenic self-peptides is thought to be
involved in the maintenance of chronic disease in autoimmune
disorders, including psoriasis. Inhibition of cathepsin S is likely
to result in a reduction in antigen presentation without an impact on
innate immunity.

VBY-891 is a next generation cathepsin S inhibitor that is a
potent, competitive and reversible inhibitor of purified cathepsin S.
It has picomolar inhibitory potency against the cathepsin S enzyme
and nanomolar inhibitory potency in cellular assays. VBY-891 is also
highly selective against human cathepsins L, B, F and K. Sustained
cathepsin S inhibition after oral dosing has been demonstrated in
vivo through the use of a biomarker. VBY-891 shows potent inhibitory
activity in models of autoimmunity and neuropathic pain. Therefore,
inhibition of cathepsin S may have therapeutic potential across a
range of dermatological conditions.

About the collaboration

The multi-million dollar collaboration between Virobay Inc. and
LEO Pharma A/S was entered in 2012 when LEO Pharma in-licensed the
promising compound from Virobay. The collaboration agreement involves
up-front payment to Virobay of USD 7m, followed by milestone payments
totalling up to USD 300m and tiered to royalties. The compound has
been tested in pre-clinical studies and the project is now entering
the next phase - a phase 1 clinical trial in healthy human
volunteers. After this trial has been completed, the plan is to do
testing on psoriasis patients later this year. If the process
proceeds as planned, the collaboration may result in an oral
treatment for psoriasis in 6-7 years.

About Virobay, Inc.

Founded in 2006, Virobay is a leader in the design, synthesis and
development of small molecule inhibitors of cysteine proteases, a
class of enzymes that are key mediators in a variety of diseases,
including autoimmunity, neuropathic pain, liver disease, cancer and
cardiovascular disorders. Virobay's clinical pipeline currently
includes product candidates in autoimmune disease, neuropathic pain
and liver fibrosis. For more information, please visit
http://www.virobayinc.com

About LEO Pharma

LEO Pharma helps people achieve healthy skin. By offering care
solutions to patients in more than 100 countries globally, LEO Pharma
supports people in managing their skin conditions. Founded in 1908
and owned by the LEO Foundation, the healthcare company has devoted
decades of research and development to delivering products and
solutions to people with skin conditions. LEO Pharma is headquartered
in Denmark and employs approximately 5,000 people worldwide.

For more information, visit http://www.leo-pharma.com.

Photo:
http://photos.prnewswire.com/prnh/20130221/595427

ots Originaltext: Virobay, Inc. and LEO Pharma A/S
Im Internet recherchierbar: http://www.presseportal.de

Contact:
Contact: Robert Booth, President and CEO, Virobay,
+1-650-833-5703; Eva Louise Østergaard, Senior Communications
Manager, LEO
Pharma, +45-4137-1207, mail: eva.oestergaard@leo-pharma.com