Kiadis Pharma Provides ATIR(TM) Update: Two Year Follow-Up Data Show No Cases of Transplant Related Mortality

FDA Grants ATIR(TM) Orphan Drug Status as a Medicinal Cell Based Therapy to Reduce Transplant Related Mortality

AMSTERDAM, April 28, 2010 - Kiadis Pharma today provided an update on its cell therapy product
ATIR(TM) developed for mismatched bone marrow transplants. ATIR(TM) continues
to show excellent clinical results in patients who received a mismatched bone
marrow transplantation from a family member donor. The two year follow up
data from the phase I/II study show no Transplant Related Mortality (TRM) in
a group of 10 high risk leukemia patients who received an efficacious dose of
ATIR(TM). The overall survival of this group after two years is 70%. These
results compare favorably to outcomes of bone marrow transplantations from a
full matching donor.

In addition, the FDA has granted ATIR(TM) an Orphan Drug Designation as a
cell based therapy for the reduction of Transplant Related Mortality caused
by Graft versus Host Disease (GvHD) and/or infections following allogeneic
bone marrow transplantation.

Transplant related mortality is predominantly caused by acute Graft
versus Host Disease (GvHD) or infections. Today, bone marrow transplants
require a full match between patient and donor, and prophylactic use of
immune suppressants post transplantation is essential to limit and manage
risk of acute GvHD. However, this approach leaves patients without an active
immune system for a prolonged period post transplantation, resulting in
increased mortality due to infections.

ATIR(TM) is a cell based product of mismatched donor immune cells from
which the acute GvHD causing cells have been removed. By eliminating the risk
of severe acute GvHD, the prophylactic use of immune suppressants can be
avoided post transplantation, quickly giving patients a functioning immune
system and ultimately resulting in a reduced Transplant Related Mortality
(TRM).

"The FDA's decision to grant ATIR an Orphan Drug Designation underscores
the significant potential of our program for bone marrow transplant patients
and their families. We are excited and encouraged by the clinical success to
date, and are focused on rapidly developing ATIR to better serve this patient
community " said Manja Bouman, CEO of Kiadis Pharma.

About ATIR(TM)

ATIR(TM) is a cell based therapy of donor T-lymphocytes depleted of
alloreactive T-cells and is infused after a patient receives a mismatched
bone marrow transplantation to reduce Transplant Related Mortality. ATIR(TM)
is designed to prevent severe acute GvHD while providing an early immune
reconstitution to fight infections and remaining tumor cells, thereby
reducing TRM and improving overall survival. Moreover, it enables the use of
a mismatched, related (haplo-identical) donor, thus providing virtually
everyone with an immediately available donor and treatment and addressing a
high unmet medical need. Today patients eligible for an allogeneic
transplantation, but without a matched donor available, have no treatment
options left. ATIR(TM) can be considered a truly individualized medicine
since it is prepared for each patient specifically.

ATIR(TM) is currently in a multinational, registration clinical study,
with sites in Europe and Canada open for enrollment.

About Kiadis Pharma

Kiadis Pharma is an oncology focused biopharmaceutical developing
products that offer novel treatment options for terminally ill cancer
patients and address significant unmet medical needs. The key focus
indication for Kiadis Pharma is limitations and complications of
hematopoietic stem cell transplantation procedures. Kiadis Pharma is located
in Amsterdam, The Netherlands. For more information about Kiadis Pharma,
please visit www.kiadis.com.

For more information please contact for: European Media, Kiadis Pharma B.V., Eefje Simpelaar, Director Communications, Email: e.simpelaar at kiadis.com, Tel: +31-20-3140250, Mob: +31-6-10829344; US Media: Jennifer James, Alta Partners for Kiadis Pharma, jjames at altapartners.com, Tel: + 1-(415)-362-4022