Study of 203Pb-RMX-VH-PIB Dosimetry and Biodistribution in Patients With Glioblastoma Multiform (GBM) and Pancreatic Ductal Adenocarcinoma (PDAC)

This is an early-stage clinical trial designed to test a new imaging drug called 203Pb-RMX-VH-PIB. The study will use SPECT/CT scans to see how the drug spreads through the body and how much radiation is delivered to different organs. The trial will enroll 20 patients who have either glioblastoma multiforme (GBM), an aggressive brain tumor, or pancreatic ductal adenocarcinoma (PDAC), a type of pancreatic cancer. Patients may be newly diagnosed, have recurrent disease, or have stable tumors. For GBM patients, the drug's distribution will be compared with MRI scans to see if it highlights the tumor areas effectively. For PDAC patients, the study will track how the drug behaves in pancreatic tumors. Participants will be divided into four groups to study both biodistribution and dosimetry in each cancer type. Each participant will receive a single intravenous injection of the drug, followed by several whole-body SPECT/CT scans. To ensure safety, vital signs will be measured before and after the injection, and blood and urine samples will be collected at multiple time points. A 12-lead ECG will also be performed to monitor heart rhythm, and results will be reviewed by the investigator. Any side effects or health changes will be closely monitored and recorded for 30 days after administration. The goal of this exploratory study is to better understand how 203Pb-RMXVH- PIB works in the body and to gather important safety and radiation data in patients with GBM and PDAC.

Inclusion criteria

• Signed informed consent.
• Subjects aged ≥18 years.
• Karnofsky status ≥60.
• Negative urine pregnancy test in women of childbearing potential.
• Histologically confirmed and /or highly suspicious GBM (Adult type Astrocytoma grade IV both IDH-Mutant and IDH-Wild Type) including primary, recurrent or stable enhancing residual or primary, recurrent or stable enhancing residual PDAC.

a. GBM group i. Contrast enhanced Brain MRI image with results compatible with GBM within the 2 weeks of dosing day.

ii. Tumor size of ≥ 1.0 cm in any dimension by MRI. iii. No antiangiogenic therapy within 4 weeks of the day of dosing. iv. No chemotherapy within 2 weeks of the day of dosing. v. Subjects receiving corticosteroids must be on a stable or decreasing dose regimen prior to enrollment b. PDAC group i. No chemotherapy within 2 weeks of the day of dosing ii. Tumor size of ≥ 1.0 cm in any dimension by MRI or CT

• Recent blood test results (within 4 weeks pre-dose) as follows:

• WBC: ≥ 2 x 109/L
• Haemoglobin: ≥ 8 g/dL
• Platelets: ≥75 x 109/L
• ALT, AST, AP ≤ 5 times ULN
• Bilirubin: ≤ 2 times ULN
• Creatinine clearance ≥ 60 mL/min, calculated by the Cockcroft-Gault equation

Exclusion criteria

• Known hypersensitivity to RMX-VH peptide analogue, 203Pb-RMX-VH-PIB, 203Pb (Lead) , or any of the excipients of 203Pb-RMX-VH-PIB.
• Inability to undergo MRI or CT/SPECT/CT scans
• Current somatic or psychiatric disease/condition that may interfere with consent or the objectives and assessments of the study.
• Pregnancy or plans to conceive during the course of study participation.
• In GBM groups participants requiring MRI: History of hypersensitivity or contraindication to gadolinium-based contrast agents, including prior allergic or anaphylactoid reactions to gadolinium contrast media, or any condition (e.g., severe renal impairment, acute kidney injury) that, in the investigator's judgment, increases the risk associated with gadolinium administration.
• In PDAC groups participants requiring CT scans: Any contraindications to iodinated contrast agents include a history of severe hypersensitivity or allergic reaction to iodinated contrast media, significant renal impairment (e.g., eGFR < 30 mL/min/1.73 m² or acute kidney injury), uncontrolled hyperthyroidism or other thyroid disorders that may worsen with iodine exposure, prior contrast-induced nephropathy, pregnancy, and any unstable medical condition such as severe heart failure or hemodynamic instability that, in the investigator's judgment, increases the risk of contrast administration.
• Male and female participants of childbearing potential who are unwilling or unable to use an acceptable method of contraception for the duration of the study.
• Women who are breastfeeding
• Participants who are currently receiving treatment with statins (HMG-CoA reductase inhibitors), including but not limited to atorvastatin, rosuvastatin, pitavastatin, simvastatin, lovastatin, pravastatin, or fluvastatin, are excluded unless the medication has been discontinued for at least four (4) drug half-lives prior to administration of the investigational product