Maintenance Therapy for ATM-Deficient Pancreatic Cancer by Multiple DNA Damage Response Interferences after...

Area of Science:

• Oncology
• Genetics
• Pharmacology

Background:

• Pancreatic ductal adenocarcinoma (PDAC) has a poor prognosis, with rising mortality rates projected.
• Maintenance therapy with PARP inhibitors shows promise in a subset of PDAC patients with germline BRCA1/2 mutations.
• The applicability of DNA damage response (DDR) targeted maintenance therapy to a broader PDAC population remains unexplored.

Purpose of the Study:

• To evaluate the efficacy of multi-DDR interference (mDDRi) as a maintenance therapy in a preclinical model of PDAC.
• To compare mDDRi maintenance therapy against continuous FOLFIRINOX treatment in ATM-deficient PDAC.
• To assess the potential of mDDRi for PDAC patients beyond germline BRCA1/2 mutations.

Main Methods:

• A placebo-controlled, three-armed preclinical trial using orthotopically transplanted ATM-deficient PDAC cell lines.
• Kaplan-Meier survival analysis, cross-sectional imaging, and histological examination.
• In vitro assays to investigate treatment effects on cellular behavior and genetic alterations.

Main Results:

• Median overall survival was significantly prolonged in the mDDRi maintenance arm compared to continuous FOLFIRINOX.
• The survival benefit correlated with increased DNA-damage load, improved disease control, and reduced metastatic burden.
• In vitro studies indicated that FOLFIRINOX could select for invasive subclones, which were subsequently eliminated by mDDRi.

Conclusions:

• Multi-DDR interference (mDDRi) demonstrates efficacy as a maintenance therapy in a preclinical PDAC setting.
• This study supports mDDRi as a novel therapeutic strategy for PDAC, extending beyond germline BRCA1/2 mutations.
• The findings suggest mDDRi can overcome chemoresistance mechanisms and reduce metastatic potential in PDAC.