Home News Top-line data from all patients…

~ Additional ATIR101™ data also selected for three poster presentations at EBMT ~

Amsterdam, The Netherlands, March 1, 2016, – Kiadis Pharma N.V. (“Kiadis Pharma” or
the “Company”) (Euronext Amsterdam and Brussels: KDS)
, a clinical stage
biopharmaceutical company developing innovative T-cell immunotherapy treatments for
blood cancers and inherited blood disorders, today announces that key data from the
Company’s ongoing single-dose Phase II clinical trial (NCT01794299/EudraCT 2012-004461-
41) with its lead product ATIR101™ has been selected for an oral presentation to discuss the
top-line data at the 42nd Annual Meeting of the European Society for Blood and Marrow
Transplantation (EBMT) on April 3-6, 2016 in Valencia, Spain. Three abstracts on additional
ATIR101™ data and the ATIR101™ development program have also been accepted for poster
presentations at EBMT.

The oral presentation entitled ‘Donor lymphocytes depleted of alloreactive T-cells (ATIR101)
improve overall survival and reduce transplant related mortality in a T-cell depleted
haploidentical HSCT: Results from a Phase 2 Trial in patients with AML and ALL’
will be
delivered in Room B6 on Monday April 4, 2016 at 16:05 CET by Dr. Denis-Claude Roy,
Professor of Medicine at the University of Montreal and principal investigator for the study.
The presentation will include the full dataset on the primary endpoint of the study
(Transplant Related Mortality at six months post transplantation) which will also be put into
perspective with other current approaches in the literature for patients lacking a fully
matched donor, such as the Baltimore approach using post-transplant cyclophosphamide.

Oral and poster presentations at EBMT:

Oral Presentation
Monday April 4, 2016 at 16:05 CET (Room B6)

  • Title: Donor lymphocytes depleted of alloreactive T-cells (ATIR101) improve overall survival
    and reduce transplant related mortality in a T-cell depleted haploidentical HSCT: Results from
    a Phase 2 Trial in patients with AML and ALL.
    Presenting author: Denis-Claude Roy

Poster Presentations
Monday April 4, 2016 from 17:15-19:00 CET, Poster Area

  • P020: Title: Leukemia-associated antigen reactive T-cells in ATIR101, a recipient-specific
    allodepleted T-cell product facilitating haploidentical HSCT.
    Presenting author: Jurjen Velthuis

Tuesday April 5, 2016 from 17:15-19:00 CET, Poster Area

  • P442: Title: Effect of graft source on safety and efficacy in patients undergoing
    hematopoietic stem cell transplantation.
    Presenting author: Stephan Mielke
  • P462: Title: An exploratory, open-label, multicenter study to evaluate safety and efficacy
    of a two-dose regimen of ATIR101 in patients with a hematologic malignancy, who
    received a CD34-selected hematopoietic stem cell transplantation from a haploidentical
    Presenting author: Stephan Mielke

Full abstracts will be made available on the EBMT website
(http://www.ebmt2016.org/abstracts.html) but data presented during the oral presentation
will contain additional data that was not yet available at the time of abstract submission.

About ATIR101™
For patients suffering from blood cancers, an allogeneic hematopoietic stem cell
transplantation (HSCT) is generally regarded as the most effective curative approach. During
an HSCT treatment, the bone marrow, harbouring the diseased cancer cells, is completely
destroyed and subsequently replaced by stem cells in the graft from a healthy donor. After an
HSCT treatment it usually takes the patient at least six to twelve months to recover to nearnormal
blood cell levels and immune cell functions. During this period, the patient is highly
vulnerable to infections caused by bacteria, viruses and fungi but also to disease relapse.

ATIR101™ (Allodepleted T-cell ImmunotheRapeutics) provides for a safe donor lymphocyte
infusion (DLI) from a partially matched (haploidentical) family member without the risk of
causing severe Graft-versus-Host-Disease (GVHD). The T-cells in ATIR101™ will help fight
infections and remaining tumour cells and thereby bridge the time until the immune system
has fully re-grown from stem cells in the transplanted graft.

In ATIR101™, T-cells that would cause GVHD are eliminated from the donor lymphocytes using
Kiadis Pharma’s photodepletion technology, minimizing the risk of GVHD and eliminating the
need for prophylactic immune-suppression. At the same time, ATIR101™ contains potential
cancer killing T-cells from the donor that could eliminate residual cancer cells and help
prevent relapse of the disease, known as the Graft-versus-Leukemia (GVL) effect.

Therefore, ATIR101™, administered as an adjunctive immuno-therapeutic on top of HSCT,
provides the patient with functional, mature immune cells from a partially matched family
donor that can fight infections and tumour cells but that do not cause GVHD. ATIR101™ thus
has the potential to make curative HSCT a viable option to many more patients.

The Company estimates that approximately 35% of patients who are eligible and in urgent
need of HSCT will not find a matching donor in time. A partially matched (haploidentical)
family donor, however, will be available to over 95% of patients.

ATIR101™, consisting of donor T-cells that fight infections and residual tumour cells while not
eliciting severe GVHD, is designed to result in low relapse rates and low rates of death due to
infections, in the absence of severe acute GVHD.

About Kiadis Pharma
Kiadis Pharma is a clinical stage biopharmaceutical company focused on research,
development and future commercialization of cell-based immunotherapy products for the
treatment of blood cancers and inherited blood disorders. The Company believes that its
innovative products have the potential to address the current risks and limitations connected
with allogeneic hematopoietic stem cell transplantation (HSCT), being
Graft-versus-Host-Disease (GVHD), cancer relapse, opportunistic infections and limited matched
donor availability. HSCT is generally regarded as the most effective curative approach to blood
cancers and certain inherited blood disorders and the Company expects that HSCT could
become a first-choice treatment for blood cancers and inherited blood disorders once current
risks and limitations are addressed, thereby meeting a significant unmet medical need with its

The Company’s product ATIR101™ is being tested using a single-dose regimen in an open-label
fully enrolled Phase II trial in patients with blood cancer who have not found a matching
donor and where a partially matched (haploidentical) family member is used as donor for
HSCT. The primary endpoint for the final patient in this trial will be reached at the end of Q1,
2016 and top-line results will be announced in April 2016. Very encouraging and positive
interim data of this trial was presented recently at ASH2015.

In addition, the Company is enrolling blood cancer patients in a further Phase II clinical trial to
study the safety and efficacy of administrating a second dose of ATIR101™ to further improve
the HSCT outcome.

The European Medicines Agency (EMA) has issued an Advanced Therapy Medicinal Product
(ATMP) certificate for manufacturing quality and non-clinical data to the Company, and to
date Kiadis Pharma is one of only five companies that have received such a certificate.

ATIR101™ has been granted Orphan Drug Designations both in the US and Europe.

ATIR201™ will be developed for inherited blood disorders with an initial focus on
thalassaemia, an inherited blood disorder which results in improper oxygen transport and
destruction of red blood cells in a patient. ATIR201™ is expected to enter Phase I/II clinical
development for thalassaemia in the first quarter of 2016. Kiadis Pharma recently announced
a collaboration with the Thalassaemia International Federation (TIF), an internationally
renowned organisation that seeks to address the needs of patients, carers, healthcare
professionals and the general public in the area of thalassaemia.

Kiadis Pharma is based in Amsterdam, the Netherlands and its shares are listed on Euronext
Amsterdam and Euronext Brussels.

Company Contact:
Manfred Rüdiger, CEO
Kiadis Pharma
Entrada 231-234
1114 AA Amsterdam-Duivendrecht
The Netherlands
Tel. +31 20 314 02 50

International Media and Investor Contact:
Mary-Jane Elliott, Lindsey Neville, Hendrik Thys
Consilium Strategic Communications
Tel: +44 (0) 203 709 5708

Forward Looking Statements
Certain statements, beliefs and opinions in this press release are forward-looking, which
reflect Kiadis Pharma’s or, as appropriate, Kiadis Pharma’s directors’ current expectations
and projections about future events. By their nature, forward-looking statements involve a
number of risks, uncertainties and assumptions that could cause actual results or events to
differ materially from those expressed or implied by the forward-looking statements. These
risks, uncertainties and assumptions could adversely affect the outcome and financial effects
of the plans and events described herein. A multitude of factors including, but not limited to,
changes in demand, competition and technology, can cause actual events, performance or
results to differ significantly from any anticipated development. Forward looking statements
contained in this press release regarding past trends or activities should not be taken as a
representation that such trends or activities will continue in the future. As a result, Kiadis
Pharma expressly disclaims any obligation or undertaking to release any update or revisions
to any forward-looking statements in this press release as a result of any change in
expectations or any change in events, conditions, assumptions or circumstances on which
these forward-looking statements are based. Neither Kiadis Pharma nor its advisers or
representatives nor any of its subsidiary undertakings or any such person’s officers or
employees guarantees that the assumptions underlying such forward-looking statements are
free from errors nor does either accept any responsibility for the future accuracy of the
forward-looking statements contained in this press release or the actual occurrence of the
forecasted developments. You should not place undue reliance on forward-looking
statements, which speak only as of the date of this press release.