Plerixafor and Cemiplimab in Metastatic Pancreatic Cancer

Inclusion Criteria:

Age ≥18 years.

* Eastern Cooperative Oncology Group (ECOG) performance status 0 or 1
* Have histologically or cytologically-proven ductal pancreatic cancer.
* Have metastatic disease.
* Have documented radiographic disease progression after previous systemic chemotherapy given in a neoadjuvant, adjuvant, locally advanced or metastatic setting.
* Patients with the presence of at least one measurable lesion.
* Willing to have to a tumor biopsy.
* Life expectancy of greater than 3 months.
* Patients must have adequate organ and marrow function defined by study - specified laboratory tests.
* Woman of childbearing potential must have a negative pregnancy test and follow contraceptive guidelines as defined per protocol.
* Men must use acceptable form of birth control while on study.
* Ability to understand and willingness to sign a written informed consent document.

Exclusion Criteria:

* Known history or evidence of brain metastases.
* Had chemotherapy, radiation, or steroids within 14 days prior to study treatment.
* Have received any investigational drugs, a live vaccine, any allergen hyposensitization therapy, growth factors or major surgery within 28 days prior to study treatment.
* Require any antineoplastic therapy.
* Had surgery within 28 days of dosing of investigational agent.
* Has received any prophylactic vaccine within 14 days of first dose of study drug.
* History of prior treatment with anti-CXCR4.
* Have used any systemic steroids within 14 days of study treatment.
* Patients receiving growth factors including, but not limited to, granulocyte-colony stimulating factor (G-CSF), Granulocyte-macrophage colony-stimulating factor (GM-CSF), erythropoietin, within 14 days of study drug administration.
* Hypersensitivity reaction to any monoclonal antibody.
* Evidence of clinical or radiographic ascites.
* Have clinically significant and/or malignant pleural effusion.
* Patient with uncontrolled intercurrent illness including, but not limited to, uncontrolled infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social situations that would limit compliance with study requirements.
* Has an active known or suspected autoimmune disease.
* Prior tissue or organ allograft or allogeneic bone marrow transplantation.
* All toxicities attributed to prior anti-cancer therapy other than alopecia and fatigue must have resolved to grade 1 (National Cancer Institute Common Terminology Criteria for Adverse Events \[CTCAE\], version 5) or baseline before administration of study drug.
* Infection with HIV or hepatitis B or C at screening.
* Patient has a pulse oximetry of \<92% on room air.
* Patient is on supplemental home oxygen.
* Has uncontrolled intercurrent acute or chronic medical illness or any use of illicit drugs or substance abuse.
* Patient is unwilling or unable to follow the study schedule for any reason.
* Woman who are pregnant or breastfeeding.
* Have rapidly progressing disease, as judged by the investigator.
* History of significant, recurrent, unexplained postural hypotension in the last 6 months.