Monopar Announces Positive Preclinical Therapeutic Isotope Data for its MNPR-101 Radiopharma Program

WILMETTE, Ill., March 05, 2024 (GLOBE NEWSWIRE) -- Monopar Therapeutics Inc. (Nasdaq: MNPR), a clinical-stage biopharmaceutical company focused on developing innovative treatments for cancer patients, today announced positive preclinical imaging data of a therapeutic radioisotope bound to its proprietary uPAR (urokinase plasminogen activator receptor) targeting agent MNPR-101. The data clearly demonstrate highly preferential uptake in the tumor. This is an extension of the tumor imaging and efficacy data Monopar released on February 22 (link), where Monopar disclosed biodistribution data with a diagnostic imaging radioisotope (Zirconium-89) as well as efficacy data with therapeutic radioisotopes (e.g., Actinium-225) bound to MNPR-101 in human tumor xenograft models. The new imaging data released today provide additional support for the tumor-targeting ability of MNPR-101 and help explain the near complete elimination of tumors (link) observed after a single injection of therapeutic radioisotopes bound to MNPR-101.

Biodistribution of a Therapeutic Radioisotope Conjugated to MNPR-101
Two of the most commercially successful radiopharmaceuticals, Pluvicto and Lutathera, use the therapeutic radioisotope Lutetium-177 (Lu-177). Beyond killing cancer cells, this radioisotope has the added advantage that its biodistribution can be visualized via SPECT (single-photon emission computed tomography) imaging. Monopar collected a sequential SPECT imaging time-series utilizing MNPR-101 conjugated to Lu-177 (MNPR-101-Lu) in a uPAR-expressing human pancreatic cancer xenograft model. The results can be seen in Figure 1. High specificity and durable uptake of MNPR-101-Lu in the tumor relative to normal tissue is readily apparent, and these results are consistent with the previously released data for Monopar’s diagnostic imaging radiopharmaceutical MNPR-101-Zr.

“Delivering a high dose to the tumor relative to normal tissue is of central importance in radiopharmaceutical therapy,” said Andrew Cittadine, Monopar’s Chief Operating Officer. “These data help explain the compelling and durable anti-tumor benefits observed to-date in preclinical studies using MNPR-101 conjugated to therapeutic radioisotopes.”

Monopar recently announced it received Human Research Ethics Committee (HREC) clearance in Australia to commence a Phase 1 dosimetry clinical trial for MNPR-101-Zr in advanced cancer patients (link). The data disclosed today further support Monopar’s efforts to create a radiodiagnostic and radiotherapeutic pairing to image and treat uPAR-positive cancers.