Molecular Partners Presents New Preclinical Data for Next-Generation T Cell Engager MP0632 at SITC 2026

“These new data highlight that our logic-gated Switch-DARPin TCEs can address one of the central challenges in solid tumors: achieving potent anti-tumor activity while avoiding side-effects on healthy tissues that express the same targets. The clean in situ safety data on primary mesothelial cells and lung pleura is compelling and exactly the kind of evidence we need to support advancing MP0632 into IND- enabling studies in cancer indications co-expressing MSLN and EpCAM,” said Martin Steegmaier, Ph.D., Chief Scientific Officer of Molecular Partners. He added: “These new data validate the potential of the Switch-DARPin platform to unlock tumor antigens so-far considered undruggable.”

The SITC poster outlines the following key findings:

• Potent and selective tumor cell killing, with efficacy comparable to a clinical-stage benchmark T-cell engager but a substantially improved safety profile
• Safe integration of CD2 co-stimulation, enabling sustained T-cell activity
• No detectable impact on primary human mesothelial or epithelial cells and no evidence of mononuclear cell infiltration in the lung pleura of mice expressing human EpCAM and MSLN

These data provide preclinical proof-of-concept that logic-gated Switch-DARPins can selectively target TAAs considered undruggable for TCEs to date, turning MSLN and EpCAM into a “clean” target pair. These results build on previously presented data demonstrating regression of established tumors expressing both EpCAM and MSLN, with minimal impact on tissue expressing only one antigen. In addition, the Switch-DARPin design allowed for safe use of potent co-stimulation for efficient tumor cell killing with low cytokine release profile.

Taken together, the preclinical data support advancing MP0632 into IND-enabling studies for solid tumors co-expressing MSLN and EpCAM, such as ovarian, endometrial, lung and pancreatic cancers.

Molecular Partners explores the broad therapeutic potential of its DARPin platforms, including Switch-DARPins inside and outside of oncology, through strategic partnerships and platform-derived spin-out opportunities, representing potential upside beyond its strategic focus on radiotherapeutics.

For further details, please contact:

Seth Lewis, EVP Corporate Finance
Concord, Massachusetts, U.S.
seth.lewis@molecularpartners.com
Tel: +1 781 420 2361

Laura Jeanbart, PhD, Head of Portfolio Management & Corporate Communications
Zurich-Schlieren, Switzerland
laura.jeanbart@molecularpartners.com
Tel: +41 44 575 19 35