# Overcoming multidimensional immunotherapy resistance in PDAC: from microenvironment to clinic

## TL;DR

This paper reviews why immunotherapy fails in pancreatic cancer and proposes new strategies to overcome resistance by targeting the tumor's immune environment.

## Contribution

The paper introduces a novel '3D+R' framework for multidimensional immunotherapy in PDAC, emphasizing dynamic immune ecosystem approaches.

## Key findings

- Single-target immunotherapies are insufficient for overcoming PDAC's immune resistance.
- Combining de-desmoplasia, de-adenosine, and rational sequencing may reshape PDAC's immune-desert phenotype.
- Emerging strategies like cDC1-based vaccines and STING agonism show potential for durable clinical responses.

## Abstract

Pancreatic ductal adenocarcinoma (PDAC) remains one of the deadliest cancers, with immunotherapy yielding <10% objective response rates (ORR) due to its profoundly immunosuppressive tumor microenvironment (TME). This review integrates preclinical and clinical evidence (2018-2026) to dissect how stromal desmoplasia, myeloid dominance, T-cell exclusion, and impaired antigen presentation converge to form an immune-privileged niche. Key resistance pathways, including cGAS-STING, Hedgehog, and NF-κB, are discussed alongside emerging strategies such as CAR-T cells, mRNA neoantigen vaccines, STING agonists, CD39/CD73 blockade, and cDC1-based vaccines. Despite incremental progress, durable responses remain rare, emphasizing that single-target interventions are insufficient. We propose a “3D+R” framework, De-desmoplasia, De-adenosine, De-novo antigen, and Rational sequencing, to guide multidimensional, biomarker-driven immunotherapy design. Approaches such as timed cDC1 vaccination, patient-tuned STING agonism, and metabolic checkpoint inhibition exemplify how PDAC’s immune-desert phenotype may be reshaped toward an immune-reactive state. Conceptualizing PDAC as a dynamic immune ecosystem rather than a mutation-driven entity may ultimately transform sporadic responses into durable and predictable clinical benefit.