Inclusion Criteria:
* Men and women, age ≥18 years.
* Evidence of IPMN as confirmed by MRI/Magnetic Resonance Cholangiopancreatography (MRCP) or pathology with biomarker results from Endoscopic Ultrasound-Guided Fine Needle Aspiration (EUS/FNA).
* IPMN must be suitable for active surveillance as defined by the international Kyoto guidelines and the European guidelines. Patients eligible for our study will have IPMN with no "high-risk stigmata" and no "worrisome features" and also have a neoplasm size of 1-\<3 cm.
* Able to complete all of the periodic activities of active surveillance as defined by the international Kyoto guidelines (2024) (Appendix VII) and the European guidelines (clinic visit evaluation, blood work, MRI/MRCP, and EUS).
* Eastern Cooperative Oncology Group = 0-2.
* Participants must have adequate organ and marrow function.
* Participants with known history or current symptoms of cardiac disease, or history of treatment with cardiotoxic agents, should undergo a clinical risk assessment of cardiac function using the New York Heart Association Functional Classification (see Appendix VI). To be eligible for this trial, participants should be class I-II.
* Agrees to avoid dietary sources of increased DT3 and abstain from consuming non-study DT3 supplements, any other dietary supplements, herbal remedies and over the counter (OTC) medicines (except use of aspirin for which data will be collected in Oncore) beginning 3 days prior to start of study drug and throughout duration of the study. DT3 levels are extremely low in normal foods. Therefore, no specific foods need to be avoided. All supportive care medications, e.g., antiemetics, antidiarrheals growth factors etc. may be used at the discretion of the treating physician and according to institutional guidelines.
* Ability to understand and the willingness to sign a written informed consent document.
* Participants must agree to refrain from getting pregnant, breastfeeding or fathering a child for the duration of the study. Female participants of child-bearing potential and male participants with a female partner of child-bearing potential must agree to use an effective birth control method, as specified in the informed consent form, throughout the study and for 6 months following the last dose of DT3. For purposes of this study, child-bearing potential is defined as a premenopausal woman without permanent sterilization who has the potential to become pregnant by being exposed to sexual intercourse with a non-sterilized male partner. Examples of birth control methods include:
* Oral birth control pills
* Birth control patch
* Implanted (injectable contraceptive hormones or mechanical products such as intrauterine device)
* Barrier methods (such as: diaphragm, condoms, or spermicides)
* Tubal ligation or vasectomy
* Abstinence (no sexual intercourse)
Exclusion Criteria:
* Evidence of Pancreatic Ductal Adenocarcinoma (PDAO or other cancers (excluding non-melanoma skin cancer) or metastatic disease.
* Concurrent systemic chemotherapy for any other cancer.
* Use of increased dietary sources of DT3, non-study DT3 supplements, any other dietary supplements, herbal remedies and OTC medicines (except use of aspirin for which data will be collected in Oncore) which may affect the study outcome unless the participant is willing to discontinue taking them 3 days prior to start of study drug DT3 and for the duration of the study. DT3 levels are extremely low in normal foods. Therefore, no specific foods need to be avoided.
* Participants may not be receiving any other investigational agents.
* History of allergic reaction attributed to vitamins.
* Patient is lactating, pregnant or planning to become pregnant during the trial.
