A Study of NALIRIFOX in Combination With Radiation Therapy in People With Pancreatic Ductal Adenocarcinoma (PDAC)

Inclusion Criteria: 1. Subject has been informed about the nature of the study, has agreed to participate in the study, and has signed the informed consent form before participation in any study-related activities. 2. Individuals with a history of other malignancies are eligible if they have been disease-free for at least 2 years and are deemed by the investigator to be at low risk for recurrence of that malignancy. Individuals with the following cancers are eligible if diagnosed and treated within the past 5 years: cervical cancer in situ, DCIS, stage I prostate cancer, and basal cell or squamous cell carcinoma of the skin. 3. A multidisciplinary discussion has been undertaken/planned which can include (a) discussion with medical/surgery oncology, (b) Hepatopancreaticobiliary Disease Management Team conference presentation, (c) direct consultation, with confirmation on consensus plan for TNT strategy and potential for future surgery. This plan needs to be documented in the medical record prior to initiation of treatment. 4. Male or nonpregnant and nonlactating female aged ≥18 years. 1. Women of child-bearing potential (i.e., fertile, following menarche, and until becoming postmenopausal unless permanently sterile; permanent sterilization methods include hysterectomy, bilateral salpingectomy, and bilateral oophorectomy) must test negative for pregnancy at the time of screening on the basis of a urine or serum pregnancy test. Postmenopausal women are defined as those who have had an absence of menstruation for at least 2 years. If necessary, follicle-stimulating hormone results \>50 IU/L at screening are confirmatory in the absence of a clear postmenopausal history. 2. Female subjects of reproductive potential must agree to use two effective methods of birth control during the study and for 9 months after the last dose of study medication. 3. Male subjects must agree to use condoms during the study and for 4 months after the last dose of study medication' Disease-specific inclusion criteria: 1. Histologically or cytologically confirmed PDAC that has not been previously treated. 2. Radiographically BR or LA PDAC in accordance with the NCCN 2.2021 definition, without evidence of distant metastases by CT. 3. Inoperable status after surgical exploration due to presence of locally advanced, unresectable disease without metastases, in patients who have recovered from surgery, is allowed. 4. Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1. 5. Hematological, biochemical, and organ function inclusion criteria: 1. Absolute neutrophil count (ANC) ≥1500/mm\^3 without the use of hemopoietic growth factors within 7 days before treatment 2. Platelet count ≥100,000/mm\^3 . 3. International normalized ratio (INR) \<1.5 unless the patient is receiving anticoagulation therapy, in which case a therapeutic INR is acceptable. Anticoagulation therapy with low-molecularweight heparin or warfarin, whether medically indicated, is permitted. 4. Adequate renal function, as evidenced by serum/plasma creatinine level \<1.6 mg/dL Exclusion Criteria: 1. Presence of metastatic pancreatic cancer (M1 disease) 2. Any other medical or social condition deemed by the investigator to be likely to interfere with a subject's ability to sign informed consent, cooperate, and participate in the study or who is likely to interfere with the interpretation of the results. 3. Unwilling or unable to comply with study procedures and/or study visits. 4. Medical co-morbidities, that preclude major abdominal surgery 5. Histologic diagnosis other than adenocarcinoma; however, adenosquamous variants are acceptable. 6. Receipt of chemotherapy, prior abdominal radiotherapy, and/or definitive resection for pancreatic cancer. 7. Grade \>2 neuropathy. 8. Pregnant and/or nursing. 9. Uncontrolled active infection, which would preclude with the exception of resolving cholangitis which in the investigator opinion would render the treatment hazardous. 10. Known hypersensitivity to any of the components of the chemotherapeutic agents 11. Receipt of concurrent investigational therapy or within 30 days of protocol initiation. Additional criterion for the immunoPET imaging sub-study (n=20) 12. Previous anaphylactic reaction to human, humanized or chimeric antibody. 13. Refusal or inability to tolerate the scanning procedure (e.g. due to claustrophobia).