Inclusion Criteria:
Able and willing to provide written informed consent. Adults aged 18 years or older. Histologically confirmed pancreatic ductal adenocarcinoma (PDAC) with measurable disease per RECIST v1.1.
Previously treated with at least one line of chemotherapy for metastatic or unresectable disease, including a fluoropyrimidine-based or gemcitabine-based regimen, or have a contraindication to these therapies.
No radiation therapy, targeted therapy, or chemotherapy within 14 days prior to first study treatment; no immunotherapy or biologic therapy within 28 days prior to first study treatment.
Recovery to ≤ Grade 2 from clinically significant toxicities of prior therapy. ECOG Performance Status 0-2. Estimated life expectancy greater than 3 months. Adequate organ function, including adequate hematologic, hepatic, and renal function.
Participants with treated brain metastases may be enrolled if clinically stable for at least 1 month.
Willing to comply with study procedures and contraceptive requirements. Participants with HIV may be enrolled if receiving antiretroviral therapy and CD4 count is >400 cells/µL.
Participants with hepatitis B may be enrolled if viral load is undetectable and appropriately treated; participants with hepatitis C may be enrolled following curative treatment.
Demonstrated tetanus toxoid (TT) immune responsiveness, either at baseline or following administration of a tetanus toxoid booster during screening.
Exclusion Criteria:
- History of chronic comorbidities that would significantly limit participation in the study, including severe heart failure (NYHA Class III-IV), end-stage renal disease, substance dependence, or inadequate venous access, as determined by the investigator.
Candidate for curative-intent surgical resection.
Surgery within 2 weeks prior to first study treatment.
Evidence of hepatic cirrhosis or clinically/radiographically significant ascites.
Blood transfusion within 14 days prior to study treatment or requirement for frequent blood transfusions (>2 per month).
Treatment with systemically active corticosteroids within 28 days before study treatment (except low-dose dexamethasone ≤2 mg/day or prednisone ≤10 mg/day).
Systemic antibiotic therapy within 14 days prior to first dose of Lm-LLO-TT.
Receipt of another investigational product or vaccine within 28 days prior to first study treatment.
Receipt of any vaccine other than the protocol-required tetanus toxoid booster within 4 weeks before study treatment or during the initial DLT evaluation period.
Major surgery, significant traumatic injury, unhealed surgical wounds, or planned surgery requiring general anesthesia within 28 days before study treatment.
Active, uncontrolled HIV, hepatitis B, hepatitis C, or HTLV-1 infection, or CD4 count <400 cells/µL.
Presence of implanted prosthetic devices, including orthopedic prostheses, pacemakers, or prosthetic heart valves.
Chronic immunosuppressive therapy for autoimmune or rheumatologic conditions.
Pregnant or breastfeeding individuals.
Active uncontrolled bacterial infection requiring intravenous antibiotics, fever >38.1°C, or unexplained fever within 7 days before Day 1.
History of Guillain-Barré syndrome within 6 weeks of a previous tetanus toxoid vaccination or prior Arthus-type hypersensitivity reaction to tetanus vaccine.