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 LRMolecular PartnersAG (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.

"We are proud to advance our second Radio-DARPin candidate into development, together with our partner Orano Med, for patients with MSLN expressing cancers. The promising preclinical data indicate a favorable biodistribution profile and highlight the unique approach to targeting MSLN with MP0726," said Patrick Amstutz, Ph.D., CEO of Molecular Partners.

MP0726 represents the second Radio-DARPin program to move into pre-clinical development. The first Radio-DARPin program, MP0712 targeting DLL3, is on track to dosing the 1^st patient in a Phase 1 study in the US in the second half of 2025.

Details of the presentation:

Preclinical characterization of a Lead-212 Radio-DARPin Therapeutic to selectively target membrane-bound mesothelin in solid tumors
Date & Time: 24 June 2025; 2:50-3:00 pm CST
Session: SS38 Radiopharmaceutical Oncology - Preclinical and Early Phase (2:30-3:45 pm CST)

About ²¹²Pb-based Radio-DARPins
Molecular Partners' Radio-DARPin platform is being developed to provide a unique and innovative delivery system for radioactive payloads, with exquisite targeting capabilities of DARPins combined with the optimally balanced safety and tumor killing of ²¹²Pb. DARPins are ideal vectors for efficient delivery of therapeutic radionuclides to solid tumors, while overcoming some historic limitations of radioligand therapy approaches, thanks to their small size as well as high specificity and affinity. Molecular Partners and Orano Med are developing targeted alpha radio-therapeutics against up to ten targets, including the tumor-associated protein Delta-like ligand 3 (DLL3) and mesothelin (MSLN).

About Molecular Partners AG
Molecular Partners AGand find us on LinkedIn and Twitter / X @MolecularPrtnrs

About Orano Med
Orano Med, a subsidiary of the Orano Group, is a clinical-stage biotechnology company which develops a new generation of targeted therapies against cancer using the unique properties of lead-212.

For further details, please contact:
Molecular Partners:
Seth Lewis, SVP Investor Relations & Strategy
Concord, Massachusetts, U.S.
[e-mail]
Tel: [phone]

Laura Jeanbart, PhD, Head of Portfolio Management & Communications
Zurich-Schlieren, Switzerland
[e-mail]
Tel: [phone]

Orano Med:
Sophie Letournel
Head of Strategy, governance, and communication
[e-mail]
Tel: [phone]

Cautionary Note Regarding Forward-Looking Statements

Any statements contained in this press release that do not describe historical facts may constitute forward-looking statements as that term is defined in the Private Securities Litigation Reform Act of 1995, as amended, including without limitation: implied and express statements regarding the clinical development of Molecular Partners' current or future product candidates; expectations regarding timing for reporting data from ongoing clinical trials or the initiation of future clinical trials; the potential therapeutic and clinical benefits of Molecular Partners' product candidates and its RDT and Switch-DARPin platforms; the selection and development of future programs; Molecular Partners' collaboration with Orano Med including the benefits and results that may be achieved through the collaboration; and Molecular Partners' expected business and financial outlook, including anticipated expenses and cash utilization for 2025 and its expectation of its current cash runway and the expected use of proceeds from the October 2024 offering. These statements may be identified by words such as "aim", "anticipate", "expect", "guidance", "intend", "outlook", "plan", "potential", "will" and similar expressions, and are based on Molecular Partners' current beliefs and expectations. These statements involve risks and uncertainties that could cause actual results to differ materially from those reflected in such statements. Some of the key factors that could cause actual results to differ from Molecular Partners' expectations include its plans to develop and potentially commercialize its product candidates; Molecular Partners' reliance on third party partners and collaborators over which it may not always have full control; Molecular Partners' ongoing and planned clinical trials and preclinical studies for its product candidates, including the timing of such trials and studies; the risk that the results of preclinical studies and clinical trials may not be predictive of future results in connection with future clinical trials; the timing of and Molecular Partners' ability to obtain and maintain regulatory approvals for its product candidates; the extent of clinical trials potentially required for Molecular Partners' product candidates; the clinical utility and ability to achieve market acceptance of Molecular Partners' product candidates; the potential that Molecular Partners' product candidates may exhibit serious adverse, undesirable or unacceptable side effects; the impact of any health pandemic, macroeconomic factors and other global events on Molecular Partners' preclinical studies, clinical trials or operations, or the operations of third parties on which it relies; Molecular Partners' plans and development of any new indications for its product candidates; Molecular Partners' commercialization, marketing and manufacturing capabilities and strategy; Molecular Partners' intellectual property position; Molecular Partners' ability to identify and in-license additional product candidates; unanticipated factors in addition to the foregoing that may cause Molecular Partners' actual results to differ from its financial and business projections and guidance; and other risks and uncertainties set forth in Molecular Partners' Annual Report on Form 20-F for the year ended December 31, 2024 and other filings Molecular Partners makes with the SEC from time to time. These documents are available on the Investors page of Molecular Partners' website at www.molecularpartners.com. In addition, this press release contains information relating to interim data as of the relevant data cutoff date, results of which may differ from topline results that may be obtained in the future. Any forward-looking statements speak only as of the date of this press release and are based on information available to Molecular Partners as of the date of this release, and Molecular Partners assumes no obligation to, and does not intend to, update any forward-looking statements, whether as a result of new information, future events or otherwise.