Molecular Partners Presents New Preclinical Data Highlighting Radio-DARPins’ Amenability to Multiple Isotopes

ZURICH-SCHLIEREN, Switzerland and CONCORD, Mass., March 19, 2026 (GLOBE NEWSWIRE) — Molecular Partners AG (SIX: MOLN; NASDAQ: MOLN), a clinical-stage biotech company developing a novel class of custom-built protein drugs known as DARPin therapeutics (“Molecular Partners” or the “Company”), today announced it will hold an oral presentation outlining new preclinical data on Radio-DARPins at the 3rd Global Radiopharmaceuticals Development Summit, taking place in Shanghai, China on March 19–20, 2026.

The presentation will outline the Radio-DARPins’ suitability to different isotopes with data on two Radio-DARPin candidates, each specific for a different tumor target. The results of studies in tumor-bearing mice show highly comparable biodistribution profiles for both Radio-DARPin candidates labeled with Lutetium-177 (¹⁷⁷Lu) or with Lead-203 (²⁰³Pb), with similar uptake and washout rates. Imaging with ¹⁷⁷Lu can be indicative of behavior with the therapeutic isotope Actinium-225 (²²⁵Ac), and similarly with ²⁰³Pb for ²¹²Pb.

“Our recent data confirms that our Radio-DARPin-vector design allows interchangeability of alpha-isotopes, including ²¹²Pb and ²²⁵Ac,” said Patrick Amstutz, Ph.D., CEO of Molecular Partners. “This feature offers us the opportunity and flexibility to evaluate Radio-DARPin candidates in an isotope-agnostic manner and to choose the most suitable therapeutic isotope, as late as with initial clinical data, without having to restart the entire drug discovery and development process – a significant advantage to tailor our candidates to patient needs.”

Details of the presentation

DARPins for targeted alpha therapy: from promising MP0712 first in-human data to opportunities for next Radio-DARPin candidates
Presenter: Daniel Steiner, Ph.D., SVP of Technology and Research
Time: 9:25 am CST, Friday, March 20
Location: Meeting Room B – IND Filing and Clinical Development Progress

The full presentation can be found here.

MP0712, Molecular Partners’ DLL3-targeted ²¹²Pb-based Radio-DARPin candidate co-developed with strategic partner Orano Med, is in an ongoing Phase 1/2a trial in the US (NCT07278479). Imaging data of MP0712 carrying the diagnostic isotope ²⁰³Pb under compassionate care are supportive of clinical development plans of MP0712 carrying the therapeutic isotope ²¹²Pb for patients with small cell lung cancer (SCLC) and other DLL3-expressing neuroendocrine cancers.

In February 2026, Molecular Partners entered into an agreement with Eckert & Ziegler, leading specialist in isotope-related components for nuclear medicine and radiation therapy, to enable the development and manufacturing of Radio-DARPin therapeutics. Eckert & Ziegler will support Molecular Partners with a comprehensive range of services covering development activities for Radio-DARPins with ²²⁵Ac as therapeutic payload and ¹⁷⁷Lu as imaging payload.