177Lu-PSMA (177Lu-PNT2002) in PSMA-Positive Adenoid Cystic Carcinoma

Inclusion Criteria: * Histologic confirmation of ACC (primary or metastatic tumor). Central review not required but local pathology review required (at Johns Hopkins or Stanford). * Patients must have recurrent or metastatic ACC with measurable disease per RECIST 1.1, not amenable to definitive surgery or radiotherapy. * Patients must have at least 1 lesion positive on PSMA-PET, as defined by standard uptake value (SUV) ratio of tumor to liver greater than one. * Patient can have any or no prior systemic therapies. * At least 28 days must have elapsed between last anti-cancer treatment administration and the initiation of study treatment, or at least 5 half-lives of the prior systemic therapy must have elapsed (whichever is shorter). * Patient must have resolution of all previous treatment related toxicities to CTCAE version 5.0 grade of ≤ 2. * Patient must be ≥ 18 years of age. * Patient must have an Eastern Cooperative Oncology Group (ECOG) performance status ≤ 2. For female patients with childbearing potential or male patients with partners of childbearing potential, agreement to use barrier contraceptive method (condom) and to continue its use for 6 months from receiving the last dose of 177Lu-PSMA. Female patients with childbearing potential will undergo a urine pregnancy test. Pregnant female participants are excluded. * Patient must have the ability to understand and the willingness to sign a written informed consent document. Exclusion Criteria: * Spinal cord compression or impending spinal cord compression. * Suspected pulmonary and/or liver metastases (greater \>10 mm in largest axis). * Unable to lie flat during or tolerate PET/CT. * Refusal to sign informed consent. * Any medical comorbidities that might preclude safe participation in the study. Additional inclusion criteria only relevant if Cohort 2 participants enrolled: * Adequate bone marrow reserve and organ function as demonstrated by complete blood count and chemistry panel completed within the prior 28 days demonstrating: 1. Platelet count of \>100 x109/L 2. White blood cell (WBC) count \> 3,000/mL 3. Neutrophil count of \> 1,500/mL 4. Hemoglobin ≥ 10 g/dL 5. Estimated glomerular filtration rate (eGFR) \> 50 mL/min based upon Chronic Kidney Disease- Epidemiology Collaboration (CKD-EPI) equation. Due to safety concerns relating to renal clearance and toxicity of 177Lu-PSMA, patients with estimated GFR between 50 - 60 mL/min will require a 99mTc-TPA GFR test and only patients with non-obstructive pathology will be included in the study. 6. Aspartate transaminase (AST) and alanine aminotransferase (ALT) ≤5 x upper limit of normal (ULN), total bilirubin \< 3 x ULN 7. Total bilirubin \< 3 x ULN (except if confirmed history of Gilbert's disease) 8. Serum albumin \> 30 g/L Additional exclusion criteria only relevant if Cohort 2 participants enrolled: * Inadequate bone marrow reserve and organ function as detailed in eligibility criteria. * Patient is participating in a concurrent investigative treatment protocol involving radiotherapy, surgery, or systemic anti-cancer agents. * Patient receiving any other investigational agents.