Oral Presentation 36th Lorne Cancer Conference 2024

Selective targeting of integrins αVβ8 and αVβ1 within the dynamic ecosystem of pancreatic cancer to improve the overall anti-tumour response. (#4)

Dannielle Upton 1 2 , Diego Chacon Fajardo1 1 2 , Sofia Omari 1 2 , Sean Porazinski 1 2 , Benjamin McLean 1 2 , Diana Schuhmacher 1 2 , Aji Istadi 1 2 , Australian Pancreatic Cancer Genome Initiative 3 , Vishal Kothari 4 , Darren Finklestein 4 , Tim Machajewski 4 , Fernando Rock 4 , Scott M Turner 4 , Marina Pajic 1 2
  1. University of New South Wales Sydney, Sydney, NSW, Australia
  2. Garvan, Darlinghurst, NSW, Australia
  3. https://www.pancreaticcancer.net.au, Sydney, NSW, Australia
  4. Pliant Therapeutics, , South San Francisco, CA, USA

Pancreatic ductal adenocarcinoma (PDA) has a 5-year survival of less than 10% and remains the 3rd leading cause of cancer-related death in Western societies. New treatment options are urgently needed. We previously characterized molecular subsets of PDA, including fibrotic elements of the disease, associated with pre-clinical and clinical response to select tailored treatment strategies1-4. TGF-β promotes stromal cell reprogramming, immunosuppression, and fibrinogenesis in cancers, including PDA5,6. Integrins αVβ8 and αVβ1 are important activators of TGF-β signalling. Selective integrin blockade has recently emerged as a promising therapeutic approach to address TGF-β-mediated immunotherapy resistance and improve anti-tumour response across cancer models7-9. Here, we assessed the in vivo efficacy of small molecule inhibitor PLN-76104, a selective inhibitor of αVβ1, and PLN-101095, a dual inhibitor of αVβ8 and αVβ1, in well-annotated models of advanced PDA.

Dual targeting of αVβ8 and αVβ1 with PLN-101095 in the syngeneic LSL-KrasG12D/+; LSL-Trp53R172H/+; Pdx1-Cre (KPC) model effectively reduced tumour growth by 45% in comparison to vehicle, and significantly delayed disease progression in vivo. Single cell analysis of PLN-101095-treated KPC pancreatic tumours revealed a positive reprogramming of malignant cells from a mesenchymal to a more epithelial-like state. This effect was further associated with an upregulation of MHC type I/II markers and corresponding downregulation of pro-metastatic factors across diverse cancer sub-populations. Additionally, combining PLN-101095 with anti-programmed death receptor-1 antibody (anti mPD-1 antibody) further improved survival in this aggressive model of metastatic PDA. In a second syngeneic model, Pan02, PLN-101095 in combination with anti mPD-1 antibody significantly reduced tumour growth, while increasing CD8+ lymphocyte infiltration. Combination PLN-101095 with Anti-PD1 increased MHC and IFN gene expression. Finally, utilizing patient-derived models of metastatic PDA revealed that both PLN-104 and PLN-101095 significantly blocked tumour growth, improved the response to standard of care (SoC) chemotherapy Gemcitabine/Abraxane, and reduced metastatic spread to distant sites.

These data provide scientific rationale for the design of future PLN-101095 and SoC chemotherapy as well as immunotherapy combinations in pancreatic cancer, with Phase I first-in-human oncology studies with PLN-101095 plus ICB already underway.

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