ThromboGenics and BioInvent to Receive EUR10 Million Milestone as Partner Roche Begins New Clinical Study with TB-403

Trial to Study Patients with Colorectal and Ovarian Cancer

LEUVEN, Belgium and LUND, Sweden, May 17, 2010 - ThromboGenics NV (Euronext Brussels: THR) and BioInvent
International AB (OMXS: BINV) announce today that their partner Roche (SIX:
RO, ROG; OTCQX: RHHBY) will begin an imaging study with the novel anti-cancer
antibody TB-403 (RG7334) in patients with metastatic, treatment-refractory,
colorectal and ovarian cancers. ThromboGenics and co-development partner
BioInvent will receive a milestone payment of EUR10 million from Roche under
the terms of the strategic alliance agreement signed in June 2008.
ThromboGenics, which discovered TB-403, receives 60% and BioInvent 40% of all
revenue from the alliance with Roche for this anti-cancer antibody.

This trial is a multi-centre, open-label (monotherapy),
dose-finding study with intravenous TB-403. The primary objective of the
study will be to establish the TB-403 concentration-pharmacodynamic (PD)
effect relationship using DCE-MRI (dynamic contrast-enhanced magnetic
resonance imaging) and to identify the minimally PD effective dose. The trial
will recruit up to 50 patients across three European sites.

With the start of this study, Roche will assume responsibility
for all future development of TB-403, continuing the work started by
ThromboGenics and BioInvent. A Joint Steering Committee made up of
representatives from Roche, ThromboGenics and BioInvent will continue to
oversee research and development activities. In addition, Roche will continue
to provide funding to ThromboGenics and BioInvent for research activities
related to TB-403.

A Phase I trial found that TB-403 was well tolerated with no
reported dose limiting toxicity. The results from this Phase I study were
presented at the AACR-NCI-EORTC International Conference on Molecular Targets
and Cancer Therapeutics in Boston, U.S. in November 2009.

Dr. Patrik De Haes, CEO of ThromboGenics commented, "We are
very pleased to report today's important milestone as a result of Roche's
decision to move forward with the development of TB-403. The fact that Roche
has initiated this study marks a positive turning point, indicating that
ThromboGenics and BioInvent have successfully completed their
responsibilities for clinical development. We have always maintained that
this selective anti-angiogenic therapy could play an important role in the
treatment of cancer, and we very much look forward to reporting the results
of this trial."

Svein Mathisen, CEO of BioInvent, commented: "This important
milestone underpins our belief that TB-403 could become an important product
for the treatment of cancer. The Roche alliance has so far generated EUR65
million in revenues to date to ThromboGenics and BioInvent. In the short
term, we expect additional payments to be made, as Roche progresses this
product through early stage development. In total, there is the potential for
a further EUR435 million in milestone payments plus product royalties."

Notes to Editors

The novel mechanism of action of TB-403 represents a
potentially promising cancer therapy. It is a humanized monoclonal antibody
directed towards placental growth factor (PIGF), expected to act by blocking
the formation of the new blood vessels that are required for tumour growth.
Preclinical exploration of PIGF biology suggests a role in tumour
angiogenesis and metastasis and a limited role in the maintenance of normal
vasculature. This mode of action could result in therapeutic benefit with an
acceptable side effect profile.

Legal disclaimer

This press release contains statements about the future,
consisting of subjective assumptions and forecasts for future scenarios.
Predictions for the future only apply as of the date they are made and are,
by their very nature, in the same way as research and development work in the
biotech segment, associated with risk and uncertainty. With this in mind, the
actual outcome may deviate significantly from the scenarios described in this
press release.

About ThromboGenics

ThromboGenics is a biopharmaceutical company focused on the
discovery and development of innovative medicines for the treatment of eye
disease, vascular disease and cancer. The Company's lead product microplasmin
has completed its first Phase III clinical trial for the non-surgical
treatment of back of the eye diseases. Microplasmin is also being evaluated
in Phase II clinical development for additional vitreoretinal conditions. In
addition, ThromboGenics is developing novel antibody therapeutics in
collaboration with BioInvent International; these include TB-402 (anti-Factor
VIII), a long acting anti-coagulant, and TB-403 (anti-PlGF) for cancer in
partnership with Roche.

ThromboGenics is headquartered in Leuven, Belgium. The Company
is listed on Eurolist by Euronext Brussels under the symbol THR. More
information is available at www.thrombogenics.com.

About BioInvent

BioInvent International AB, listed on the NASDAQ OMX Stockholm
(BINV), is a research-based pharmaceutical company that focuses on developing
antibody drugs. The Company currently has four clinical development projects
within the areas of thrombosis, cancer and atherosclerosis. The Company has
signed various strategic alliances around these product candidates and is
developing them in collaboration with partners including Genentech, Roche and
ThromboGenics.

These projects are based around a competitive and in substance
patented antibody development platform. The scope and strength of this
platform is also utilised by partners, such as ALK-Abello, Bayer HealthCare,
Daiichi Sankyo, ImmunoGen, Mitsubishi Tanabe, OrbusNeich, UCB and XOMA.

More information is available at www.bioinvent.com.

    For further information, please contact:

    ThromboGenics NV
    Patrik De Haes, MD                       Stuart Laermer
    Chief Executive Officer                  Chief Business Officer
    Tel : +32-(0)-16-75-13-10                Tel: +1-(212)-201-0920
    E-mail: patrik.dehaes@thrombogenics.com  E-mail:
                                             stuart.laermer@thrombogenics.com

    Citigate Dewe Rogerson
    Amber Bielecka, David Dible, Nina Enegren
    Tel: +44-(0)-207-638-95-71
    E-mail: amber.bielecka@citigatedr.co.uk

    BioInvent International AB
    Svein Mathisen                           Cristina Glad
    President & CEO                          Executive Vice President
    Tel: +46-(0)-46-286-85-67                Tel: +46-(0)-46-286-85-51
    Mobile: +46-(0)-708-97-82-13             Mobile: +46-(0)-708-16-85-70
    E-mail: svein.mathisen@bioinvent.com     E-mail:
                                             cristina.glad@bioinvent.com

    College Hill (media enquiries)
    Katja Toon, Justine Lamond, Anastasios Koutsos
    Tel: +44-(0)-20-7866-7857
    E-mail: bioinvent@collegehill.com

    ThromboGenics NV                         BioInvent International AB (publ)
    Gaston Geenslaan 1                       Co. reg. No. 556537-7263,
    B-3001 Leuven                            Address: Solvegatan 41
    Belgium                                  Mailing address: SE-223 70 LUND
    Tel: +32-(0)-16-75-13-10                 Tel: +46-(0)-46-286-85-50
    www.thrombogenics.com             info@bioinvent.com
                                             www.bioinvent.com

ThromboGenics NV, Patrik De Haes, MD, Chief Executive Officer, Tel : +32-(0)-16-75-13-10, E-mail: patrik.dehaes at thrombogenics.com; Stuart Laermer, Chief Business Officer, Tel: +1-(212)-201-0920, E-mail: stuart.laermer at thrombogenics.com; Citigate Dewe Rogerson, Amber Bielecka, David Dible, Nina Enegren, Tel: +44-(0)-207-638-95-71, E-mail: amber.bielecka at citigatedr.co.uk; BioInvent International AB, Svein Mathisen, President & CEO, Tel: +46-(0)-46-286-85-67, Mobile: +46-(0)-708-97-82-13, E-mail: svein.mathisen at bioinvent.com; Cristina Glad, Executive Vice President, Tel: +46-(0)-46-286-85-51, Mobile: +46-(0)-708-16-85-70, E-mail: cristina.glad at bioinvent.com; College Hill (media enquiries), Katja Toon, Justine Lamond, Anastasios Koutsos, Tel: +44-(0)-20-7866-7857. E-mail: bioinvent at collegehill.com