On November 12, 2025 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"), reported the presentation of new data on MP0712, its lead Radio-DARPin targeting DLL3, at the Targeted Radiopharmaceuticals (TRP) Summit Europe, highlighting first encouraging human images and supporting mechanism of action data. MP0712 is being developed with strategic partner Orano Med for the treatment of patients with small cell lung cancer (SCLC) and other neuroendocrine cancers. Molecular Partners presents an example case with images of a patient today as courtesy of the Nuclear Medicine Research Infrastructure (NuMeRI) in South Africa. The NuMeRI team, led by Prof. Mike Sathekge, plans to report the full imaging and dosimetry data of MP0712 at the Theranostics World Congress (TWC) in January 2026.
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"The images show targeted delivery of MP0712 into tumors and limited exposure in healthy organs of concern such as kidney and liver. This is an important milestone for MP0712, which is indicative of its potential performance in a clinical setting when carrying 212Pb as therapeutic radioactive payload and providing a strong basis for advancing its clinical development. We are continuing preparations for the upcoming Phase 1 trial with MP0712 and look forward to advancing additional Radio-DARPin programs in 2026," said Patrick Amstutz, Ph.D., CEO of Molecular Partners.
The presented case study of a patient who received 203Pb-MP0712 indicates specific uptake in the tumor lesions visible at 24 hours and sustained over 4 days, with limited accumulation in healthy organs, as intended. To promote tumor uptake via internalization over time, MP0712 is half-life engineered to maintain sufficient amounts of drug in the blood, visible at the early imaging time points. These early results are in line with previously presented pre-clinical data and further support the intended mechanism of action of MP0712.
203Pb and 212Pb are an element-equivalent pair of lead (Pb) isotopes, with 203Pb used for imaging and 212Pb for therapeutic applications (targeted alpha therapy, TAT). As a "matched pair", pre-treatment imaging with 203Pb provides a prediction of treatment behavior with 212Pb.
The imaged patient was initially diagnosed with Stage 3 small cell lung cancer and had a treatment history of radiotherapy and chemotherapy; the patient was then re-classified as Stage 4 post imaging with MP0712 due to observed liver metastases. This patient is a case example of a series of patients who received MP0712 for imaging use as part of a Named Patient Access Program under the legal framework in South Africa for compassionate care (also referred to as Section 21 of the Medicines and Related Substances Act). The Company believes that, due to the prior treatment and tumor stage of the patient, this case is illustrative of the patient population likely to be recruited in its planned Phase 1/2a in the US.
In addition to first-in-human images, the presentation at TRP highlights that MP0712 is rapidly internalized and accumulates intracellularly in DLL3-expressing cells in vitro. The data suggests that MP0712 can achieve high tumor uptake in spite of very low DLL3 expression levels, leveraging internalization and replenishment pathways of DLL3 as well as optimal binding properties and tunable half-life of the DLL3-binding DARPin.
The Phase 1 Investigational New Drug (IND) application for MP0712, for the treatment of small cell lung cancer (SCLC) and other DLL3-expressing neuroendocrine cancers, has been filed. Dialogue with the FDA is ongoing and, pending regulatory clearance, the Phase 1 trial is expected to initiate by the end of 2025. The Phase 1/2a study is a multi-center study in the US, with the objectives to assess safety and determine a recommended phase 2 dose for MP0712 (labeled with 212Pb). The study contains an imaging and dosimetry step with 203Pb-labeled MP0712. The Company expects initial clinical data from the study in 2026.
Details of the presentation at TRP:
Title: Internalisation of Targeted Radiopharmaceuticals: Strategic Imperative or Situational Choice?
Presenter: Daniel Steiner, PhD, SVP of Technology and Research
Time: Wednesday November 12 at 1.30pm CET
Location: Amsterdam, Netherlands
Webcast to be held today at 10am ET (4pm CET):
In addition to the presentation at TRP, Molecular Partners will host a webcast today to discuss the new data, as well as the upcoming clinical trial of MP0712 in the US. Details as follows:
For Participants who want to listen and view slides: Please register here.
For Participants who may want to ask a question following the presentation: Please register here.
Participants who wish to ask a question will be provided with additional dial-in instructions to join the live conference call. These participants will have the ability to "raise their hand" and ask a verbal question during the Q&A.
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).
(Press release, Molecular Partners, NOV 12, 2025, View Source [SID1234659758])