The purpose of this research is to study the effects and safety of alternating neoadjuvant chemotherapy on borderline resectable pancreatic cancer.

Modified FOLFIRINOX (mFOLFIRINOX) and gemcitabine plus nab-paclitaxel (GnP) are two of the preferred chemotherapy treatments at this time. The U.S. Food and Drug Administration (FDA) has approved each of these treatments for patients with borderline resectable pancreatic cancer. This study will alternate these two neoadjuvant chemotherapy treatments (GnP and mFOLFIRINOX). The study doctors hope that alternating these treatments may improve the treatment response, improve tumor removal (also called "resectability"), and lower the risk of cancer coming back.

Inclusion Criteria:

• Age ≥ 18 years
• Diagnosis of BR-PDAC. The resectability should be officially determined with surgical oncologists at the Dartmouth Cancer Center (DCC) GI multidisciplinary Tumor Board based on NCCN Guidelines Version 2.2024 Pancreatic Adenocarcinoma.
• Patients must be able and willing to provide informed consent.
• Contrast-enhanced CT scan of the chest, abdomen, and pelvis performed within 45 days before registration.
• ECOG Performance Status: 0-1.
• Females of childbearing potential must have a negative pregnancy test done ≤ 14 days prior to study enrollment, and must agree to use a highly effective method of contraception throughout the course of protocol therapy.

Exclusion Criteria:

• Any prior receipt of chemotherapy or radiation therapy for PDAC.

• Known DPYD poor metabolizer genotype.

• Known BRCA1/2 or PALB2 mutations. If they are found to have BRCA1/2 or PALB2 mutation after inclusion to the trial, the participant will be taken off of protocol therapy (since platinum-containing therapy is preferred for these patients).

• Any confirmed second malignancy that is likely to require systemic therapy during the study period, in the opinion of the enrolling investigator.

• Any of the following baseline laboratory abnormalities:

  • Absolute neutrophil count (ANC) < 2,500/mm3
  • Platelet count < 100,000/mm3
  • Hemoglobin < 7 g/dL
  • Creatinine > 1.5 x upper limit of normal (ULN)
  • Total bilirubin > 1.5 x ULN
  • AST/ALT > 5 x ULN

• Any peripheral sensory neuropathy that meaningfully impairs performance of instrumental activities of daily living, as evaluated by the enrolling investigator.

• Patients who are unable to provide informed consent.

• Patients who are pregnant or breastfeeding.

• Patients who are incarcerated.