Home News Kiadis Pharma’s Pediatric Investigation Plan…

~ Paves the way for submission of a Marketing Authorization Application
for ATIR101™ in Europe ~

Amsterdam, The Netherlands, March 28, 2017, – 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 the Pediatric Committee (PDCO) of the
European Medicines Agency (EMA) has accepted the Company’s Pediatric Investigation Plan
(PIP) for ATIR101™ for the adjunctive treatment in hematopoietic stem cell transplantation
(HSCT) for a malignant disease. In addition, the PDCO has agreed that the Company may defer
conducting the studies defined in the PIP until after it files a Marketing Authorization
Application (MAA) in Europe for the use of ATIR101™ for the treatment of blood cancers.

The Company’s PIP provides for a Phase II trial to evaluate the safety and efficacy of ATIR101™
as an adjunctive treatment on top of an HSCT in pediatric patients up to 18 years of age with a
hematologic malignancy, who are eligible for an HSCT but without the availability of a fully
matched donor. Patients will receive either an HSCT from a partially matched (haploidentical)
related family donor with the adjuvant infusion of ATIR101™, or an HSCT using umbilical cord
blood stem cells from an unrelated donor. The primary endpoint of the trial will be Graftversus-
Host-Disease-free, relapse-free survival (GRFS).

Manfred Rüdiger, PhD, Chief Executive Officer of Kiadis Pharma, commented: “The
acceptance of our pediatric development program by EMA’s PDCO is an important regulatory
milestone for ATIR101™. Furthermore, the PDCO’s decision to allow us to defer the initiation
of our PIP means the Company can submit an MAA to EMA for the use of ATIR101™ in adult
blood cancer patients substantially earlier than if it was required to complete the PIP
beforehand. This is an important step forward in our efforts to bring ATIR101™ to the market
and evidences the close and constructive interactions that Kiadis Pharma has established
with the regulatory authorities in developing ATIR101™.

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, harboring 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
near-normal 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

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 tumor 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)

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 tumor 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 tumor 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 focused on cell-based immunotherapy products for the treatment of blood
cancers and inherited blood disorders. The Company’s products have the potential to address
the risks and limitations connected with allogeneic hematopoietic stem cell transplantation
(HSCT), namely Graft-versus-Host-Disease (GVHD), cancer relapse, opportunistic infections
and limited matched donor availability. The Company believes that HSCT could become a firstchoice
treatment for blood cancers, inherited blood disorders and possibly autoimmune
diseases and solid organ transplantations.

On December 5, 2016 at the Annual Meeting of the American Society of Hematology (ASH),
the Company reported positive Phase II results with its lead product ATIR101™ in patients
with blood cancer. The data showed that ATIR101™ significantly reduced Transplant Related
Mortality and significantly improved Overall Survival. In addition, ATIR101™ did not elicit
grade III-IV GVHD in any patient. Based on these positive results, a Phase III clinical trial has
been initiated. ATIR101™ has been granted Orphan Drug Designations both in the US and

The Company’s second product candidate, ATIR201™, addresses inherited blood disorders
with an initial focus on thalassemia, a disease which results in destruction of red blood cells
in patients. ATIR201™ Phase I/II clinical development has been initiated recently.

Kiadis Pharma, based in Amsterdam, The Netherlands, was granted an Advanced Therapy
Medicinal Product (ATMP) certificate for manufacturing quality and non-clinical data by the
European Medicines Agency (EMA). The Company’s 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.