The goal of this clinical research study is to learn about the safety and tolerability of the OnVagus device when used by patients who have metastatic pancreatic cancer and are receiving chemotherapy.

Primary Objective:

To determine the safety and tolerability of the OnVagus device in patients wearing it while receiving chemotherapy.

Secondary Objective:

To determine the rate of cachexia arrest, as defined by weight stabilization or gain

Exploratory Objectives:

To analyze the changes in chemokine (C-C motif) ligand 2 (CCL2), tumor necrosis factor α (TNFa), acetylcholine (ACh), Growth/differentiation factor 15 (GDF15), Lipocalin-2 (LCN2), and liver function tests (LFTs) while patients receive vagal blockade.

To determine the device's impact on progression-free survival (PFS) and overall survival (OS) between patients receiving vagal blockade.

Inclusion Criteria:

• Patients with metastatic pancreatic cancer.

• Must have adenocarcinoma component (presence of combined histology is acceptable, as long as adenocarcinoma is present).

• Weight loss from baseline of at least 5% (Baseline weight can be anytime from diagnosis onward).

• Must have a tissue-based confirmation of diagnosis available. Tissue does not need to be a metastasis; primary tumor or prior surgery are acceptable sources.

• Must have had progression of disease after one prior line of therapy in the metastatic setting.

• Must be receiving or plan to receive another line of therapy in the metastatic setting. o If therapy is being administered outside MD Anderson, the patient is still eligible for this trial. o Enrollment onto a therapeutic clinical trial as this second line therapy is not explicitly excluded.

• Must have triple ECG results available. Patients will be ineligible if they present: o Second- or third-degree block.

  • Prolonged QT wave.
  • Atrial fibrillation or flutter.
  • Uncontrolled ventricular fibrillation or flutter.
  • Premature ventricular contractions (PVC).

Exclusion Criteria:

Exclusion Criteria

• History of cervical vagotomy on the right side of neck.
• Known structural abnormalities on the right side of neck, including but not limited to situs inversus, bulky R-neck lymphadenopathy, etc., that in the investigators' opinion would lead to inability to correctly place the device onto the vagus nerve.
• Implanted electrical device that passes through the neck (e.g.: cranial implant with battery pack in chest, and wires running through the neck).
• Metal implants in the neck, including the cervical spine.
• Recent (6 months or less) nerve block or botox injections to the head or neck.
• Pain specifically localized to the treatment area, the right side of the neck.
• Prior severe cerebrovascular disease (e.g., intracranial aneurysm, intracranial hemorrhage, stroke).
• Prior severe cardiac disease, including but not limited to coronary artery disease (CAD), prior myocardial infarction (MI), uncontrolled congestive heart failure (CHF).