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

Preclinical testing found no detectable impact on primary human mesothelial or epithelial cells.

Rhea-AI Summary

Molecular Partners (MOLN) announced new preclinical results for MP0632, a T cell engager, supporting further development in solid tumors.

MP0632 is designed to activate immune T cells when both tumor-associated proteins MSLN and EpCAM are present. Preclinical testing showed selective tumor-cell killing, with efficacy comparable to a clinical-stage benchmark T cell engager and an improved safety profile. No detectable impact was observed on primary human mesothelial or epithelial cells, and no evidence of mononuclear cell infiltration was found in the lung pleura of mice expressing human MSLN and EpCAM.

Molecular Partners said the findings support advancing MP0632 into IND-enabling studies, the studies supporting an application to begin human testing. The results build on earlier data showing regression of established tumors expressing both targets, with minimal impact on tissue expressing only one.

Positive

• Minor pointMP0632 showed selective tumor-cell killing, with preclinical efficacy comparable to a clinical-stage benchmark T cell engager.
• Minor pointMP0632 showed an improved preclinical safety profile versus the clinical-stage benchmark T cell engager.
• Minor pointPrimary human mesothelial and epithelial cells showed no detectable impact in preclinical testing.
• Minor pointLung pleura showed no evidence of mononuclear cell infiltration in mice expressing human EpCAM and MSLN.
• Minor pointIntegrated CD2 co-stimulation enabled sustained T-cell activity, with a low cytokine release profile in preclinical testing.

2 minor points

• Minor pointEarlier preclinical data showed established tumor regression with both targets present and minimal impact on single-antigen tissue.
• Minor point. Forward-looking: it has not happened yet and may not happen.Molecular Partners said the data support advancing MP0632 into IND-enabling studies for tumors co-expressing MSLN and EpCAM.

Negative

• None.

Key Terms

t cell engager, cd2 co-stimulation, cytotoxicity, ind-enabling studies

4 terms

t cell engager medical

"a logic-gated Switch-DARPin T cell engager (TCE) with integrated CD2 co-stimulation"

A T cell engager is an engineered protein drug that physically links a patient’s T cell — the immune system’s attack cell — to a diseased cell so the T cell will recognize and kill it. For investors it matters because clinical trial results, manufacturing success and safety profiles determine whether the therapy becomes a widely adopted, high-value treatment or a costly failure; think of it like a matchmaker that must reliably bring soldiers to the right target without triggering friendly fire.

cd2 co-stimulation medical

"Safe integration of CD2 co-stimulation, enabling sustained T-cell activity"

CD2 co-stimulation is an accessory immune signal delivered when the CD2 protein on a T cell binds its ligand (commonly CD58/LFA‑3) on another cell; this interaction strengthens cell–cell contact and amplifies signals from the T‑cell receptor so the T cell is more likely to activate, proliferate, and secrete cytokines. It is not the primary antigen-recognition signal but a secondary, modulatory pathway that lowers the activation threshold and influences the strength and quality of a T‑cell response.

cytotoxicity medical

"enables potent, selective cytotoxicity against cells co-expressing tumor-associated antigens"

Cytotoxicity is the ability of a substance to kill or damage living cells. Investors watch cytotoxicity results because they indicate whether a drug or chemical is likely to be effective against targeted cells (for example, cancer cells) and whether it poses safety risks to healthy tissue, which affects clinical success, regulatory approval, and commercial potential—similar to knowing if a powerful weed killer also harms the lawn around the weeds.

ind-enabling studies regulatory

"support advancing MP0632 into IND-enabling studies for solid tumors"

Ind-enabling studies are early research efforts that test whether a new drug or treatment is safe and effective enough to move forward in development. They are like preliminary tests to ensure a product works as intended before investing more resources into large-scale trials. For investors, these studies are important because successful results can signal potential progress toward bringing a new product to market, impacting its future value.

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• Logic-gated Switch-DARPin design enables potent, selective cytotoxicity against cells co-expressing tumor-associated antigens (TAAs) previously considered undruggable for T cell engagers
  
  
• Favorable safety profile, with new data indicating healthy tissues expressing either TAA remain intact
  
  
• Attractive therapeutic window underlines MP0632’s readiness for IND-enabling studies in solid tumors co-expressing MSLN and EpCAM
  
  

ZURICH-SCHLIEREN, Switzerland and CONCORD, Mass., Nov. 06, 2026 (GLOBE NEWSWIRE) -- Molecular Partners AG (SIX, NASDAQ: MOLN), a clinical-stage biotech company developing a novel class of medicines known as DARPin therapeutics (“Molecular Partners” or the “Company”), today announced the presentation of new preclinical data supporting an attractive therapeutic window for MP0632, a logic-gated Switch-DARPin T cell engager (TCE) with integrated CD2 co-stimulation, at the Society for Immunotherapy of Cancer (SITC) 2026 conference.

“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. 

Details of the presentation

Title: MP0632, a logic-gated conditional Switch-DARPin T cell engager with CD2 co-stimulation enabling selective activity against solid tumors co-expressing MSLN and EpCAM
Poster #1072, a Top 150 SITC 2026 Abstract
Date & Time: 07 Nov 2026; 12:30-1:30 and 6:40-8:10 pm MT (poster viewing times)
Location: Phoenix Convention Center (PCC) - North Building - Lower-Level- Exhibition Halls 4-6

SITC takes place November 4-8 in Phoenix, AZ, USA.
The poster will be made available on Molecular Partners' website after the presentation.

About MP0632

MP0632 is a next-generation, logic-gated T cell engager designed to activate T cells only when both MSLN and EpCAM are present. Its Switch-DARPin design enables reversible, dual-target-dependent un-masking of the CD3 binder for tumor-localized efficacy, while avoiding systemic T cell activity and limiting impact on healthy tissues. The built-in CD2 co-stimulation maintains potent and sustained tumor-localized T cell function.

About Molecular Partners AG 
Molecular Partners AG (SIX, NASDAQ: MOLN) is a clinical-stage biotech company pioneering a novel class of medicines known as DARPin therapeutics for cancer patients underserved by existing treatment modalities. Molecular Partners focuses on the development of targeted radiotherapeutics, leveraging the unique properties of DARPin miniproteins as isotope-agnostic vector. The Company’s lead medicine MP0712, targeting DLL3 and armed with ²¹²Pb, advances in a US multicenter Phase 1/2a study for patients with small cell lung cancer and other neuroendocrine cancers. Molecular Partners has established partnerships with industry leaders and academic centers covering the full value chain of radiotherapeutics. Molecular Partners, founded in 2004, has offices in both Zurich, Switzerland and Concord, MA, USA. For more information, visit www.molecularpartners.com and find us on LinkedIn.

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

Cautionary Note Regarding Forward-Looking Statements

This press release contains 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; Molecular Partners' plans to streamline its organization and related workforce reductions, and its anticipated scope, cost, timing and benefits; and Molecular Partners’ expected business and financial outlook, including anticipated expenses and cash utilization for 2026 and its expectation of its current cash runway. 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, but are not limited to, those set forth under the heading “Risk Factors” in Molecular Partners’ Annual Report on Form 20-F for the year ended December 31, 2025, 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.

FAQ

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What did Molecular Partners report about MP0632's preclinical efficacy and safety?

MP0632 showed selective tumor-cell killing, with efficacy comparable to a clinical-stage benchmark T cell engager and an improved preclinical safety profile. Testing found 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.

Which cancers could Molecular Partners study with MP0632?

Molecular Partners said the preclinical data support IND-enabling studies for solid tumors co-expressing MSLN and EpCAM, such as ovarian, endometrial, lung and pancreatic cancers. These are studies supporting an application to begin human testing, rather than reported clinical results.