Selective depletion of alloreactive T-cells while retaining virus-specific and
memory T-cells from haploidentical donor lymphocytes
Menno van der Hoorn1, Maartje Geraedts1, Angela M. Krackhardt2, Johan Maertens3, Irwin Walker4, Halvard Bönig5,
Denis-Claude Roy6, Jeroen Rovers1, Manfred Rüdiger1, Jurjen Velthuis1,*
Kiadis Pharma, Amsterdam-Duivendrecht, The Netherlands; 2 Medical Department, Klinikum Rechts der Isar, Technische Universität München,
Munich, Germany; 3 Department of Haematology, University Hospital Gasthuisberg, Leuven, Belgium; 4 Department of Medicine, McMaster
University, Hamilton, Ontario, Canada; 5 Institute for Transfusion Medicine and Immunohematology of the Goethe University and German Red Cross
Blood Service Baden-Württemberg-Hesse, Frankfurt, Germany; 6 Hôpital Maisonneuve-Rosemont, Montreal, Canada
Introduction
Day 5
Immune cells collected and mixed.
60
40
20
0
T-Cells
Monocytes
*
NK-Cells
100
Day 5
Mixture exposed to light.
TH9402 is activated by light, causing the ‘stained’
GvHD-causing T-cells to self-destruct.
TH9402 introduced.
TH9402 is retained ONLY in the GvHD-causing T-cells.
ATIR101
The remaining product is infused back and helps rebuild
their immune system to fight infections and eliminate
remaining tumour cells.
Figure 1. ATIR101 Manufacturing.
Donor cells are co-incubated with irradiated recipient cells in a
uni-directional mixed lymphocyte reaction (MLR). The activated donor
cells are loaded with TH9402 which is selectively retained in
recipient-alloreactive cells. Light-exposure converts TH9402 into its
toxic form to generate ATIR101, a selectively allo-depleted cell therapy
product for adoptive immune transfer.
1.6
1.4
1.2
*
Autologous
Recipient
3rd Party
CD3/28
Figure 4. Selective depletion of recipient-reactivty in
ATIR101
ATIR101 and original donor cells were stimulated with either
irradiated donor cells (autologous), irradiated recipient cells,
irradiated 3rd party cells or anti-CD3/28. ATIR101 is selectively
depleted of recipient-reactivity only (P<0.05).
Control
A
EBV
CMV
Influenza
*
80
60
ATIR101
40
20
Naive
Certain T-cells from the donor are activated by the
presence of the ‘foreign’ patient cells. If not eliminated,
these cells would cause GvHD in the patient.
B-Cells
Donor
ATIR101
Donor
Donor
ATIR101
Donor
CD4+
Patient
6
1.0
Figure 2. Cellular subsets in donor and ATIR101
ATIR101 and the original donor cells were phenotyped for the
presence of:
- T-cells (CD3+)
- Monocytes (CD14+)
- NK-cells (CD3-CD16/56+)
- B-cells (CD19+)
ATIR101 is strongly enriched for T-cells (>90%).
0
Patient cells
inactivated
by radiation
*
12
ATIR101
CD8+
Effector memory
Central memory
Effector
Figure 3. Memory T-cell subsets in donor and ATIR101
ATIR101 and original donor cells were characterized for the presence
of naive, effector, central or effector memory T-cells within the CD4+
and CD8+ T-cell compartment. All subsets are retained; only the
effector CD4+ T-cells are enriched in ATIR101 compared to donor
T-cells (P<0.05).
Conclusion
ATIR101 adjunctive therapy provides a broad T-cell
immunotherapy that can offer effective immune
protection without eliciting life-threatening GvHD.
It obviates the need for immunosuppressive
agents even in the high-risk haploidentical stem
cell transplantation population.
B
Precursor Frequency (PF)
Healthy
donor
Day 1–4
Donor
ATIR101
*
80
T-Cell subsets (%)
ATIR101 product desired characteristics
• ATIR101 consists essentially of T-cells (fig 2)
• ATIR101 has preserved the presence of memory and naïve
T-cells (fig 3)
• ATIR101 is selectively depleted of recipient-alloreactive T-cells,
while retaining reactivity against 3rd party and polyclonal
stimuli as determined by proliferation (fig 4)
• ATIR101 has retained pathogen specific T-cells (fig 5)
100
Cell Composition (%)
Haploidentical donor grafts may resolve the shortage of sufficient
available HLA-matched donors for treatment of leukemia patients
with a HSCT. Current techniques do not allow for such a procedure
as the presence of donor T-cells will cause severe GvHD and
absence or suppression of T-cells will lead to occurence of
opportunistic infections and potential relapse. Kiadis Pharma
developed ATIR101, a cell based medicinal product consisting of
selectively allodepleted donor T-cells, though the use of
photodynamic therapy (fig 1). In the present study, we
investigated whether ATIR101, that was infused in patients (n=23)
in a Phase II clinical trail (CR-AIR-007; NCT01794299) had all the
desired features to promote immune protection while not
eliciting GvHD in patients that received a haploidentical HSCT.
Results
Proliferation Index (PI)
1
0.04
Donor
ATIR101
0.03
0.02
0.01
0.00
3rd Party
APC
Vehicle
APC
Pathogens
Figure 5. Anti-pathogen
T-cells in donor and
ATIR101
ATIR101 and original donor
cells were stained with
PE-labeled HLA-A2 multimers
(A)
or
quantified
using
CFSE-based
proliferation
assay (B). Pathogen-specific
T-cells are preserved in
ATIR101.
Clinical Results
At 6 months follow up, none of patients treated in CR-AIR-007
revealed grade III/IV acute GvHD, and no relapses and only two
cases of TRM were observed, both occurring beyond day 100 post
HSCT. The present study demonstrates that ATIR101 is able to
promote immune protection while not eliciting GvHD in patients
that received a haploidentical HSCT.