Tislelizumab: Integrated Analysis of Tumor, Peripheral Blood, and Patient Treatment History

Desamparados Roda , Alexander Chung , Spencer Huggett , Jon Zugazagoitia , Elena Garralda , Alexander I. Spira , Yujie Zhao , Peter J. Oppelt , Anthony B. El-Khoueiry ,
Margaret E. Chen , Chunjie Jiang , Melissa Harney , Hombline Poullain , Germain Margall-Ducos , Eladio Marquez , Francisco Adrian , Jinping Gan
Hospital Clínico Universitario de Valencia , HiFiBiO Therapeutics Inc. , Hospital Universitario 12 de Octubre , Vall d’Hebron Institute of Oncology , NEXT Oncology Virginia , Mayo Clinic Florida , Washington University School of Medicine in St. Louis , University of Southern California Norris Comprehensive Cancer Center

BACKGROUND

• Agonism of tumor necrosis factor receptor-2
(TNFR2) enhances anti-tumor immunity by
stimulating T- and NK-cells in the tumor
microenvironment.

• Emunkitug (HFB200301), an anti-TNFR2 agonistic
monoclonal antibody, triggers both innate and
adaptive immune responses.

• Previously we reported Phase 1 results that
demonstrated tolerable safety profile and clinically
meaningful efficacy with emunkitug as
monotherapy and in combination with tislelizumab
(TIS) in advanced refractory solid tumors.

• Model-informed optimization of dosing led to Q2W
regimen in addition to Q4W.

• Here, we report updated safety and efficacy results
with longer follow-up time.

• In addition, we report potential biomarkers
predictive of response to emunkitug combined with
TIS.

STUDY DESIGN and PATIENT DEMOGRAPHICS

Study Design

DL (Dose Level); HFB (HFB200301); Q4W (once every 4 weeks); TIS (tislelizumab)

Demographics and Clinical Characteristics

EBV+, Epstein-Barr virus positive; ECOG PS, Eastern Cooperative Oncology Group performance status; PD-(L)1, programmed cell death protein (ligand) 1.

SAFETY PROFILE

Safety Summary of HFB200301 Q2W/Q4W ± TIS Q4W

Emunkitug Q4W/Q2W ± TIS demonstrated tolerable safety profile
• TRAEs mostly limited to Grade 1-2, including TRAEs of interest (inflammatory and cutaneous toxicity)
• No grade 4 or 5 TRAE and no TRAE leading to discontinuation or dose reduction

Cutoff: 26-Sep-2025

PRELIMINARY ANTI-TUMOR RESPONSE

Emunkitug + TIS Combination Efficacy

Clinically meaningful responses demonstrated by emunkitug + TIS
• Figure A: Partial responses in multiple indications – mesothelioma, non small cell
lung cancer, and clear cell renal cell carcinoma
• All responders had prior immunotherapy and were heavily pretreated
• Disease control rate (DCR) per RECIST 1.1 of 50% in Q2W and 36% in Q4W
combination
• Figure B: Durable clinical benefit (partial responses and stable disease per RECIST
1.1) observed

Note: 5 subjects not shown in Fig A and B had clinical progressions and did not have
radiographic assessment of their target lesions
Cutoff: 29-Sep-2025

Spatial Proximity Analysis – Tumor mIF

Spatial proximity to tumor with TNFR2+ and PD1+ immune cells

Table 2: RECIST 1.1 BOR vs Preceding Therapy

HFB200301 Q4W/Q2W + TIS (n=22)

• Figure A: Graphical representation of mIF-derived analysis of spatial proximity
to determine distance between the target cells (e.g. TNFR2+CD8 T cells) and
tumor cells
• Figure B: Distribution of all target cells’ distance from tumor cells (each row
represents individual subject)
• Figure C and D: Representative images of subjects with close (Fig C) and
distant (Fig D) median tumor cell distance to TNFR2+ CD8T

A

B

D Emunkitug + TIS
Testicular cancer
Progressive disease
Median distance: 1,328 μm

POTENTIAL BASELINE BIOMARKERS PREDICTIVE OF RESPONSE TO EMUNKITUG + TIS

Tumor – mIF: Spatial Proximity of TNFR2+CD8 or TNFR2+NK Cells to Tumor Cells as Potential Response Predictive Biomarker

and NK cells to enhance cytotoxic antitumor responses

Closer proximity of tumor cells with TNFR2+ CD8 and TNFR2+ NK cells associated with prolonged progression-free survival (PFS) in response to emunkitug + TIS
• Figure A: Emunkitug-mediated activation of TNFR2+ CD8 T cells in closer proximity to tumor cells may be predictive of response

mIF Spatial Proximity – Emunkitug + TIS:
TNFR2+ CD8T – Tumor cells

A

Cutoff: 29-Sep-2025

Periphery – Single-cell RNA & Flow Cytometry: NK Abundance as Potential Response Predictive Biomarker

High peripheral levels of suppressive subset of cytotoxic NK cells at baseline may predict clinical benefit to emunkitug + TIS
• Figure A: scRNA analysis revealed that suppressive subset of cytotoxic NK cells may predict clinical benefit (PR or SD per RECIST 1.1) to emunkitug + TIS
• Figure B: Correlation between scRNA versus flow cytometry levels of suppressive subset of NK cells

Monotherapy Emunkitug Q4W (n=27)

• Figure C and Table 1: Flow cytometry analysis showed that higher peripheral levels of suppressive subset of NK cells may be predictive of prolonged progression-free survival (PFS) and
improved DCR (PR+SD)

A

Cytotoxic NK cell count – All subjects:
scRNA vs Flow
B

Flow cytometry – Emunkitug + TIS:
Suppressive subset of cytotoxic NK vs PFS

C

Monotherapy Emunkitug Q2W (n=11)

Table 1: RECIST 1.1 BOR vs Suppressive
Subset of Cytotoxic NK

Cutoff: 29-Sep-2025

Patient Record: Immediate Prior Immunotherapy May be a Surrogate for Tumor and Peripheral Biomarkers

Immediate prior immunotherapy may be predictive of response to emunkitug + TIS combination

• Figure A and B: Subjects with immediate prior immunotherapy may be linked to closer proximity of TNFR2+CD8/NK to tumor cells and cytotoxic NK cells in the periphery at baseline
• Figure C and Table 2: Immediate prior immunotherapy may be predictive of prolonged PFS and increased DCR (PR+SD) amongst patients with indications of interest

Preceding therapy: C, Chemotherapy; T, Targeted**; IO,** Immunotherapy

IN DEPTH LOOK AT NSCLC

Cutoff: 29-Sep-2025

NOTE: Included in Figure C and Table 1 are indications of interest (ccRCC, gastric, HNSCC, mesothelioma, NSCLC)

Clinical and Biomarker Data Support Further Development in NSCLC

• Compared to 2L standard-of-care docetaxel +/- ramucirumab which reported
median PFS of 2.7 – 4.5

Early signs of improvement in PFS with emunkitug + aPD-1 in NSCLC patients,
especially in biomarker enriched patients

*Median prior LOT (3, range: 2-4); all had prior anti-PD-(L)1

Biomarker+: Closer TNFR2+CD8—Tumor proximity and/or higher peripheral cytotoxic NK

RECIST 1.1 Efficacy: Emunkitug + TIS

Biomarker-: Neither

CONCLUSIONS

• Longer follow-up continued to show tolerable safety profile and durability of the
partial responses and stable diseases in response to emunkitug + TIS.

• Integrative analysis of tumor, peripheral blood, and patient records (treatment
history / preceding therapy) identified potential biomarkers predictive of clinical
benefit and prolonged PFS in response to emunkitug + TIS.

• Predictive biomarkers in the tumors (TNFR2+CD8T in close proximity to tumor) and
periphery (higher levels of suppressive subset of cytotoxic NK cells) align with
emunkitug’s MOA in activating CD8 T and NK cells

• Suggests that the combination efficacy is dependent on emunkitug-mediated
activation of CD8 T and NK cells in addition to PD-1 blockade

• Patient enrichment for response by NK cell count via flow cytometry may be a
practical patient selection strategy for future development

• Early signs of clinically meaningful efficacy in NSCLC warrants further evaluation with
additional patients

Acknowledgments and references