Molecular Partners and Orano Med present preclinical data on mesothelin-targeting Radio-DARPin candidate MP0726 at SNMMI 2025

• MP0726, a Radio-DARPin candidate targeting mesothelin (MSLN) and intended for the treatment of ovarian cancer, is nominated for development under strategic partnership with Orano Med
• Promising tumor accumulation and attractive biodistribution shown in vivo, selective binding to membrane-bound MSLN with positive tumor to kidney ratio
  

ZURICH-SCHLIEREN, Switzerland and CONCORD, Mass. and PARIS, June 22, 2025 (GLOBE NEWSWIRE) -- Ad hoc announcement pursuant to Art. 53 LR Molecular Partners AG (SIX: MOLN; NASDAQ: MOLN), a clinical-stage biotech company developing a new class of custom-built protein drugs known as DARPin therapeutics (“Molecular Partners” or the “Company”) and Orano Med, a clinical-stage radiopharmaceutical company and a pioneer in the development of targeted alpha-particle therapies (TAT) with ²¹²Pb (lead-212), today announced the debut of MP0726, its Radio-DARPin candidate targeting mesothelin (MSLN) and will present preclinical data in an oral presentation at the 2025 Annual Meeting of the Society of Nuclear Medicine and Molecular Imaging (SNMMI), taking place June 21-24 in New Orleans, LA, USA.

The oral presentation outlines encouraging early preclinical proof-of-concept data showing that MP0726 binds with high affinity and selectivity to the membrane-proximal domain of MSLN without being impacted by shed MSLN. In vivo results in a MSLN tumor model show a favorable biodistribution with substantial uptake of the Radio-DARPin in MSLN-positive tumors, while other organs showed limited accumulation. At 24 hours post injection, tumor accumulation was up to 34%, resulting in a tumor to kidney ratio of up to 4.5.

MP0726 leverages the unique properties of DARPins to selectively bind membrane-bound MSLN, a promising target for ovarian cancer due to its differentiated expression profiles - high in tumor, and lower in healthy tissues. High levels of shed MSLN can act as a decoy receptor and have historically hampered the development of MSLN-targeted therapeutics. MP0726 is being co-developed under Molecular Partners’ strategic partnership with Orano Med.

“Our collaboration with Molecular Partners has been delivering substantial progress in a short time, reflecting the skills, passion and strong complementarity of our teams. This progress highlights the effectiveness of our joint R&D efforts, enabling us to identify and advance differentiated clinical candidates that address important unmet medical needs. With its world-class R&D capabilities, the ownership of a virtually unlimited supply of the starting isotope, and fully-integrated manufacturing supply chain, Orano Med is uniquely positioned to support the development of these important potential new medicines”, said Arnaud Lesegretain, CEO of Orano Med.