SynCo Expands Agreement with OncoMed Pharmaceuticals to Manufacture Cancer Stem Cell Antibodies

AMSTERDAM, May 3, 2010 - SynCo Bio Partners B.V., an award winning GMP biopharmaceutical
manufacturer, has expanded its current agreement with OncoMed
Pharmaceuticals, Inc., a company developing novel therapeutics that
target cancer stem cells. Under the expanded agreement, in addition to
antibody OMP-21M18, SynCo will fill batches of OncoMed's investigational
products, two additional antibodies in the OncoMed pipeline for use in Phase
I and II clinical trials.

Announcing the agreement, Pierre Warffemius, CEO, said, "We
are extremely delighted that OncoMed and SynCo's working relationship
continues to strengthen and that SynCo has been able to support this leading
biopharmaceutical company's clinical development effectively over the last
two years. We look forward to a continued mutually beneficial collaboration."

Paul J. Hastings, President and CEO of OncoMed, said, "We are
delighted to be working with SynCo on the manufacture of our novel antibodies
targeting cancer stem cells. SynCo has been a great partner and has delivered
excellent performance on our anti-DLL4 antibody, OMP-21M18, which is
currently in Phase I clinical trials. Based on our positive experience
working with them to date, we can think of no one more qualified than SynCo
to continue providing filling operations."

SynCo will fill the OncoMed antibodies at its Amsterdam-based
facility. This facility is able to fill a wide range of biopharmaceuticals
into vials, including protein, polysaccharide, and live biotherapeutics using
the latest automated filling equipment.

About OncoMed Pharmaceuticals

OncoMed Pharmaceuticals is a clinical-stage company that
discovers and develops novel therapeutics targeting cancer stem cells, the
cells believed to be capable of driving tumor growth and recurrence. A leader
in cancer stem cell research, the company has established a library of
antibodies to cancer stem cell proteins for the treatment of solid tumors
such as pancreatic, breast, colorectal and lung cancers. OncoMed's lead
candidate, OMP-21M18 is currently in Phase I clinical trials. In addition to
OMP-21M18, OncoMed's pipeline includes several novel preclinical product
candidates targeting multiple validated cancer stem cell pathways.
Privately-held, OncoMed's investors include: Nomura Phase4 Ventures, US
Venture Partners, Latterell Venture Partners, Morgenthaler Ventures, The
Vertical Group, Adams Street Partners, De Novo Ventures, Delphi Ventures, Bay
Partners and GlaxoSmithKline. Additional information can be found at the
company's website: www.oncomed.com.

About SynCo Bio Partners B.V.

SynCo Bio Partners is a GMP-licensed bulk drug substance and
final product CMO with clinical and commercial production experience in
mammalian and microbial systems. This experience has been acquired by
developing new production processes for a number of international clients and
producing a wide variety of vaccines, recombinant proteins and
live-biotherapeutic products in its state-of-the-art, GMP-licensed facilities
since inception in 2000. Focused solely on biopharmaceuticals, SynCo acts as
a strategic, long-term partner delivering product on time to the highest
quality standards. SynCo's team is committed to exceeding customer
expectations, taking a truly collaborative approach to contract
manufacturing. For more information, please visit
www.syncobiopartners.com

Contacts: SynCo Bio Partners, Joanne McCudden, Director Marketing and Sales,
+31-(0)655-34-80-74, j.mccudden at syncobiopartners.com; BCC Partners on behalf of OncoMed Pharmaceuticals, Karen L. Bergman or Michelle Corral, +1-(650) 575-1509 or +1-(415) 794-8662,
kbergman at bccpartners.com or mcorral at bccpartners.com