A NKG2D-based CAR-T therapy in a Multinational Phase 1 Dose Escalation and Expansion Study Targeting Multiple Solid and Hematologic Tumor Types

Bikash Verma1, Ahmad Awada2, Jean-Pascal H. Machiels3, Jason B. Brayer4, David A Sallman5, Tessa Kerre6, Kunle Odunsi7, Caroline Lonez8, David Edward Gilham8, Frederic Lehmann8

TPS3093

A B S T R A C T

BACKGROUND: Chimeric Antigen Receptor (CAR)-T therapy has potentially

serious limitations related to target antigen loss, toxicity due to pre-

conditioning regimen, and lack of activity in many tumor types. To overcome

these limitations, we have developed a novel CAR-T, called NKR-2,

incorporating the full-length human natural killer receptor NKG2D fused with

the human CD3 zeta signaling domain. When expressed in T-cells, the

naturally-expressed DAP10 provides co-stimulatory signals to NKR-2 to

produce cytokines and selectively target tumor cells upon recognition of up to

8 different stress-induced NKG2D ligands expressed in many solid and

hematologic malignancies. In preclinical studies, NKR-2 demonstrated long-

term anti-tumor activity towards a breadth of tumor indications, in the

absence of pre-conditioning, whilst simultaneously targeting tumor cells and

cells from the local tumor neo-vasculature and suppressive immune

environment. In our recently completed First-in-Human Phase 1 study

(NCT02203825) in hematologic cancers, a single administration of autologous

NKR-2 was safe with initial hints of clinical benefit.

METHODS: Exploiting the multiple ligand targeting capability and unique

mode of action of NKR-2, the THINK trial (THerapeutic Immunotherapy with

NKR-2) is an open-label Phase I study that will assess the safety and clinical

activity of multiple infusion NKR-2 treatment (every 2 weeks x 3 infusions) in

relapse/refractory patients with metastatic or locally advanced CRC,

urothelial carcinoma, TNBC, pancreatic cancer, recurrent epithelial ovarian

and fallopian tube carcinoma, AML/MDS and MM, post standard treatment.

The study contains two consecutive segments. The dose escalation segment

will enroll 18 patients in two separate hematologic and solid malignancy arms,

and will evaluate 3 dose levels of NKR-2 (3x108, 1x109 and 3x109 per injection)

following a 3+3 design. The expansion segment will then enroll 86 additional

patients in 7 separate cohorts for each indication with 3 steps of statistical

analysis (overall futility, cohort futility and final evaluation). The study is open

for recruitment in both EU and US (NCT03018405).

N K R - 2 C A R T - C E L L S

• NKR-2 are autologous T-cellsgenetically modified toexpress a CAR comprising afusion of the full-lengthhuman NKG2D receptor (anactivating receptor expressedmainly in humans on NK cells)with the CD3 signalingdomain.

• The NKR-2 actually works likea ‘second generation’ CAR,thanks to the association ofNKG2D with DAP10,constitutively expressed on T-cells, which provides a co-stimulatory signalcomplementing the primaryCD3 signal.

• NKR-2 construct consistsentirely of human sequencesallowing multiple NKR-2injections without theanticipated risk to induce anhumoral immune response.

T H I N K T R I A L D E S I G N & S T A T U S

THINK study (NCT03018405, EudraCT 2016-003312-12) key designaspects:

• Open-label and multinational (EU and US) phase I study with twoconsecutive segments (Figure 3).

• NKR-2 treatment administered three times every 2 weeks (Figure 4)

• Three dose-levels: 3x108, 1x109 and 3x109 NKR-2 cells/injection.

• Five solid and two hematological tumor indications (Table 1).

• No prior lymphodepletion.

• NKR-2 is supplied cryopreserved in bags containing a T-cell dose inaccordance with the dose-level which is to be administered with acentralized production center (Figure 2).

Main objectives:

• A first dose escalation segment (3+3 design) evaluating the feasibility andsafety of NKR-2 aiming at determining the recommended dose (RecD) ofNKR-2 cells separately for solid or hematological tumor types based onthe occurrence of dose limiting toxicities (DLTs) during the studytreatment until 14 days after the 3rd NKR-2.

• A second segment extending the safety study at the RecD andinvestigating initial clinical activity of NKR-2 across the seven tumorindications, separately. This segment is split in three steps withintermediate futility and safety evaluations, allowing the RecD to be stilladapted according to predefined safety rules in any specific tumor type.

Current status:

• Dose-level 2 in solid indications.

• Dose-level 1 in hematologic indications.

• Feasibility and safety – no DLTs to date.

F I G U R E S & T A B L E S

P E R S P E C T I V E S

Preclinical data suggest four differentmechanisms of action of NKR-2:

• Direct cytotoxicity against cancer cells,

• Anti-angiogenic activity potentially through targeting of NKG2D ligandsexpressed upon tumor neovasculature [7],

• Modulation of the immune tumor microenvironment through directtargeting of immunosuppressive myeloid-derived suppressor cells(MDSCs) and regulatory T-cells (Tregs), and recruitment of myeloid cellsand activated macrophages [8, 9], together resulting in

• The generation of a tumor-specific adaptive immune response capable ofprotecting against tumor re-challenge, despite relatively short-termcirculation of NKR-2 T-cells themselves [8-10].

Exploiting the targeting of NKG2D ligands by NKR-2 to fight againstdiverse tumor indications with a single generic construct combining twofeatures of innate and adaptive immunity, provides potentially a newparadigm for CAR T-cell therapy that the current protocol is designed toinvestigate.

F I G U R E 3 : O v e r v i e w o f t h e T H I N K s t u d y d e s i g n

F I G U R E 2 : N K R - 2 m a n u f a c t u r i n g p r o c e s s

F I G U R E 1 : P r e c l i n i c a l d a t a o n h u m a n p a n c r e a t i c c a n c e r m o d e l F I G U R E 4 : O v e r v i e w o f T H I N K s t u d y p r o c e d u r e s

D = day, M = Month, BM = bone marrow.

AFFILIATIONS: 1Celyad, Boston, MA; 2Medical Oncology Clinic, Institut Jules Bordet, Université Libre de Bruxelles, Brussels, Belgium; 3Institut Roi Albert II, Service d’Oncologie Médicale, Cliniques Universitaires Saint-Luc and Institut de Recherche Clinique

et Expérimentale (Pole MIRO), Université Catholique de Louvain, Brussels, Belgium; 4H Lee Moffitt Cancer Ctr and Rsrch Inst, St Petersburg, FL; 5Moffitt Cancer Center, Tampa, FL; 6Ghent University Hospital, Ghent, Belgium; 7Roswell Park Cancer Institute,

Buffalo, NY; 8Celyad, Mont-Saint-Guibert, Belgium.

REFERENCES: [1]. Carapito R, Bahram S. Immunol Rev 2015;267(1):88-116. [4]. Sentman CL, Meehan KR. Cancer J 2014;20(2):156-9. [7]. Zhang T, Sentman CL. J Immunol 2013;190(5):2455-63.[2]. Le Bert N, Gasser S. Immunol Cell Biol 2014;92(3):230-6. [5]. Demoulin B, et al. Future Oncology 2017;In Press. [8]. Barber A, et al. J Immunol 2009;183(11):6939-47.[3]. Spear P, et al. Cancer Immunity Archive 2013;13:8. [6]. Barber A, et al. Gene Ther 2011;18(5):509-16. [9]. Spear P, et al. J Immunol 2012;188(12):6389-98.

[10]. Spear P, et al. Oncoimmunology 2013;2(4):e23564.

Main eligibility criteria Disease-specific inclusion criteria

• Men or women ≥ 18 years old at the time of signing the ICF.

• Patient with specific cancer indications.

• Disease must be measurable according to the correspondingguidelines.

• No tumor metastasis in the central nervous system.

• ECOG performance status of 0 or 1 or 2 based on peripheralneuropathy from prior therapies.

• Patient with adequate bone marrow reserve, hepatic andrenal functions.

• Left ventricular ejection fraction of > 40%.

• Tumor biopsy at baseline.

• No previous cancer therapy within 2 weeks before theplanned day for the apheresis.

• No administration of concurrent growth factor, systemicsteroid, other immunosuppressive therapy or cytotoxic agent.

• No major surgery within 4 weeks before the planned day forthe first NKR-2 administration.

• Metastatic or locally advanced colorectal adenocarcinomaafter at least 2 prior standard cancer therapy regimens.

• Recurrent epithelial ovarian cancer or fallopian tubecarcinoma after at least 2 prior standard cancer therapyregimens.

• Inoperable locally advanced or metastatic urothelialcarcinoma after previous platinum-based chemotherapy.

• Metastatic or locally advanced triple-negative breast cancerafter at least 1 prior cancer therapy regimen.

• Metastatic or locally advanced pancreatic ductaladenocarcinoma with a maximum of 2 prior lines of standardtherapy regimens.

• Relapsed or refractory AML after one prior standard therapy.No previous allograft.

• Intermediate, High-risk or Very High-risk myelodysplasticsyndrome or refractory anemia with excess blasts by WHO orMDS with TP53 mutation with at least one prior treatmentwith at least 4 cycles of azacitidine or decitabine.

• Relapsing or refractory/relapsing multiple myeloma with atleast 1 prior line of systemic therapy, including prior exposureto both proteasome inhibitor (PI) and immunomodulatorydrug.

NSG mice were injected intraperitoneally (IP) with 0.5 x 106

luciferase-expressing PANC-1 tumor cells and tumorengraftment was followed by bioluminescent imaging(N=1). Twelve and nineteen days after PANC-1 injection,control mice received either HBSS buffer (HBSS group),5x106 of T cells (IP) retrovirally transduced with the wild-type NKG2D (wtNKG2D T-cells) or with theNKR-2 construct(NKR-2 group). Imaging was performed every week startingone week after tumor inoculation. Thirty-five-days posttumor injection, the final imaging showed that some micethat received the NKR-2 treatment had little tumorremaining compared to HBSS and wtNKG2D groups wheremice had a large tumor burden [5].

T A B L E 1 : E l i g i b i l i t y c r i t e r i a

• In humans, NKG2D targets eight ligands: the major histocompatibilityclass (MHC) class I chain related proteins (MICA and MICB) and the uniquelong 16 binding proteins (ULBPs 1 to 6) [1].

• A broad range of tumors express NKG2D ligands [2, 3] includinghematological and solid tumor types [3], while NKG2D ligands are absentor lowly expressed in healthy tissues [2, 3].

• NKR-2 mediate potent anti-tumor activity in vitro and in vivo, withoutprior lymphodepleting pre-conditioning [6] against both hematological(lymphoma, multiple myeloma) and solid (ovarian cancer, melanoma andpancreatic cancer (Figure 1)) tumor models [4].