DEPLETHINK - LymphoDEPLEtion and THerapeutic Immunotherapy With NKR-2

This open-label Phase I study aims at assessing primarily the safety of the NKR-2 treatment
administered after a non-myeloablative preconditioning regimen in r/r AML/MDS patients.

This Phase I study will contain two different sequential segments.

The first segment will determine the recommended investigational treatment option (schedule
of preconditioning and NKR-2 dose) and the second segment will expand to a larger number of
r/r AML/MDS patients. The first segment will evaluate the preconditioning regimen consisting
in cyclophosphamide 300 mg/m² and fludarabine 30 mg/m² daily (CYFLU) administrated 3
consecutive days daily at a specific interval prior to the NKR-2 administration. This segment
is divided into three sequential cohorts to evaluate respectively:

- Two different intervals between the preconditioning regimen and the NKR-2 administration
i.e. NKR-2 administered 3 days (T3) or 7 days (T7) after the end of the preconditioning
regimen,

- Two different NKR-2 dose-levels i.e. dose-level 1 (1x108 NKR-2/injection) and dose-level
2 (3x108 NKR-2/injection).

The second segment (extension segment) will enroll more r/r AML/MDS patients (to reach 9
evaluable patients in total) to further evaluate the recommended NKR-2 dose (1x108 or 3x108
NKR-2/injection) administered at the recommended interval (T3 or T7) after the CYFLU
preconditioning.

Each patient will receive a single administration of NKR-2 following the preconditioning
regimen. Depending on the clinical response as evaluated at the first tumor assessment,
scheduled five weeks after NKR-2 administration, two situations may arise:

- If the patient is presenting a complete remission, partial remission, or stable disease,
and meets all criteria for a consolidation cycle, then three new injections of NKR-2 at
the recommended dose defined in the ongoing THINK study (THINK RecD), without prior
preconditioning, will be administered with a two weeks interval,

- If the patient is in PD, or does not meet all criteria for the consolidation cycle
he/she will not receive any other NKR-2 injection but will follow other visits as
scheduled.

For each patient who received at least one NKR-2 administration, the overall study duration
will be 15 years after first NKR-2 administration.

The duration of the administration phase and treatment follow-up will be 24 months.

Patients will be asked to complete a total of maximum 23 visits during the treatment
administration phase, and maximum 6 visits during the treatment follow-up phase. During the
long-term safety follow-up, yearly visits will be scheduled (up to Y15).

Rationale for the study:

NKR-2 has the potential to treat many distinct tumor-types because of a broad expression and
important prevalence of the NKG2D ligands expression in various tumor types including in r/r
AML/MDS. This Phase I study will explore the hypothesis that the administration of modified
T-cells targeting NKG2D-ligands expressed by AML/MDS cells, after a prior nonmyeloablative
preconditioning treatment, in patients refractory to and/or relapsing after prior therapies,
is safe and, considering the poor outcomes and lack of therapeutic strategies for this
patient population, may have a strategic advantage over current approaches and provide
potential clinical benefit.

Objectives of the study:

Primary

To document and characterize:

• The safety of the NKR-2 treatment administration in r/r AML/MDS patients after a
non-myeloablative preconditioning.

Secondary

To document and characterize:

- The NKR-2 peripheral blood kinetics post-administration,

- Indicators of clinical activity,

- Additional indicators of safety.

Inclusion Criteria:

- The patient must have signed the written ICF and must accept that, beyond the
treatment period, and the treatment follow-up period, he/she will have to be monitored
for a LongTerm Safety Follow-Up (LTSFU) for up to 15 years after enrollment.

- Both men and women of all races and ethnic groups are eligible.

- The patient must be > =18 and < = 70 years old at the time of signing the ICF.

The patient must have either:

- A confirmed relapsed or refractory acute myeloid leukemia (AML) (> = 5% blasts in bone
marrow or in peripheral blood) after one prior therapy defined as either

- Recurrence of disease after a complete remission (CR), or

- Failure to achieve CR with initial therapy. Note: Patient with AML M3 are excluded.

A confirmed myelodysplastic syndrome (MDS) with:

- Revised International Prognostic Scoring System (R-IPSS) criteria for Intermediate,
High-risk or Very High-risk disease or refractory anemia with excess blasts by WHO or
MDS with TP53 mutation as detected by next-generation sequencing (NGS).

- Failure of prior treatment with at least 4 cycles of azacitidine or decitabine defined
as no response to treatment, loss of response at any time point, or progressive
disease/intolerance to therapy.

- The absolute peripheral blast count should be < 15,000 per micro liter.

The patient must have evaluable disease defined by:

- Revised Recommendations of the International Working Group for Diagnosis,
Standardization of Response Criteria, for AML patients,

- IWG 2006 Uniform Response Criteria for patients with Higher-Risk MDS.

- The patient must have an Eastern Cooperative Oncology Group (ECOG) performance status
< = 2.

The patient must have must have adequate hepatic and renal functions.

- Ejection fraction of > = 40%, as determined by echocardiography or a multigated
acquisition (MUGA) scan.

- Women of child-bearing potential and men must agree to use effective contraception
before, during and for at least 2 months after the last study treatment
administration.

- The patient must, in the opinion of the Investigator, be able to adhere with the study
visit schedule and all study procedures described in this protocol.

Exclusion Criteria:

- The patient has a confirmed or suspected tumor involvement in the central nervous
system (CNS). A neurological examination is to be performed systematically at
baseline. In case signs or symptoms suggestive of potential CNS disease are observed,
CNS imaging is to be performed. Peripheral neuropathy from prior therapy is
acceptable.

- Patients who have received any cancer therapy (investigational agent or not),
including but not limited to chemotherapy, small molecules, monoclonal antibodies
(e.g., immune checkpoint blockade therapies), or radiotherapy within 2 weeks before
the planned day for the apheresis.

- Patients who are planned to receive, concurrently receiving or have received any
investigational agent within 3 weeks before the planned day for the first NKR-2
administration.

- Patient is under systemic immunosuppressive drugs, unless specific cases authorized
per protocol.

- Patients who have received prior allogeneic stem cell transplantation or chimeric
antigen receptor therapy.

- Patients who are presenting persistent toxicities greater than or equal to CTCAE grade
2 caused by previous cancer therapy (except for clinically non-significant toxicities,
such as alopecia).

- Presence of any indwelling catheter or drain (e.g., percutaneous nephrostomy tube,
indwelling foley catheter, biliary drain, or pleural/peritoneal/pericardial catheter)
may be permissible unless they have a catheter-associated infection that cannot be
cleared with antibiotics. Ommaya reservoirs and dedicated central venous access
catheters such as a Port-a-Cath, peripherally inserted central catheter, or Hickman
catheter are permitted.

- Patients who underwent major surgery within 4 weeks before the planned day for the
first NKR-2 administration.

- Patients who have received a live vaccine < = 6 weeks prior to the planned day for the
first NKR-2 administration.

- Patients with uncontrolled intercurrent illness or serious uncontrolled medical
disorder including but not limited to evidence of active pneumonitis on screening
chest imaging, symptomatic congestive heart failure, unstable angina pectoris, cardiac
arrhythmia and/or pronounced disturbances of the electrical conduction system of the
heart, or significant thromboembolic events.

- Patients with significant disorder of coagulation or receiving treatment with warfarin
derivatives or heparin.

- Patients who have active infections necessitating use of antibiotics/antivirals
treatment (prophylaxis is acceptable).

- Patients with a known history of hepatitis B (HBsAg positive) or C (anti-HCV
positive).

- Patients who are known to be positive or screened positive for the human
immunodeficiency virus (HIV).

- Patients with a family history of congenital or hereditary immunodeficiency.

- Patients with a history of allergic reactions or hypersensitivity attributed to Human
serum albumin or Plasma-lyte A.

- Patient with history of idiopathic pulmonary fibrosis, organizing pneumonia,
drug-induced pneumonitis, idiopathic pneumonitis and/or active or acute exacerbation
of chronic obstructive pulmonary disease (COPD).

- Patients on supplemental home oxygen.

- Patients with history of any autoimmune disease including, but not limited to
inflammatory bowel disease (including ulcerative colitis and Crohn's Disease),
systemic progressive sclerosis (scleroderma), systemic lupus erythematosus, autoimmune
vasculitis (e.g., Wegener's granulomatosis), CNS or motor neuropathy considered of
autoimmune origin (e.g., Guillain-Barre syndrome and myasthenia gravis, multiple
sclerosis). Patients with Graves disease and vitiligo will be allowed.

- Patients with a history of a malignancy other than the one evaluated in this study
enrollment, with exception of the following circumstances:

- Patients with a history of malignancy who have been adequately treated and have been
disease-free for at least 1 year, and

- Patients with adequately treated active non-invasive cancers (such as nonmelanomatous
skin cancer or in-situ bladder, cervical and breast cancers).

- Patients with psychiatric/social situations or addictive disorders that may compromise
the ability of the patients to give informed consent or to comply with the study
procedures.

- Female patients who are pregnant or lactating.