Monopar Therapeutics Inc. announced it has received Human Research Ethics Committee (HREC) clearance in Australia to commence a Phase 1 dosimetry trial of its novel radiopharmaceutical MNPR-101-Zr. The MNPR-101-Zr Phase 1 dosimetry clinical trial will enroll patients with advanced cancers and will utilize positron emission tomography (PET) imaging to assess tumor uptake, normal organ biodistribution, and safety. MNPR-101-Zr is a zirconium-89 (imaging radioisotope) labeled version of MNPR-101, Monopar?s proprietary first-in-class humanized monoclonal antibody that is highly selective against the urokinase plasminogen activator receptor (uPAR).

PET imaging studies in preclinical xenograft models of triple-negative breast, colorectal, and pancreatic cancers displayed high and selective uptake of MNPR-101-Zr in these uPAR-expressing tumors. The imaging results, along with corresponding in vivo efficacy studies with actinium-225 (Ac-225, a powerful alpha-emitting therapeutic radioisotope) bound to MNPR-101 in preclinical xenograft tumor models, support the development MNPR-101 as a targeted radiopharmaceutical for multiple advanced cancer indications. If the tumor uptake, biodistribution, and safety look encouraging in this Phase 1 clinical trial, which is anticipated to enroll around 12 patients and to initiate in the near future, the plan is to evaluate the efficacy in humans of a therapeutically radio-labeled version of MNPR-101 bound to an isotope such as Ac-225.