On November 7, 2025 Nouscom, a clinical-stage biotech company developing next-generation off-the-shelf and personalized neoantigen cancer immunotherapies, reported the presentation of new clinical and translational data on its lead candidate NOUS-209 at the 40th Annual Society for Immunotherapy of Cancer (SITC) (Free SITC Whitepaper) Meeting.

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Following positive safety and immunogenicity data reported at AACR (Free AACR Whitepaper) 20251, these additional results from the Phase 1b/2 trial of NOUS-209 in Lynch Syndrome (LS) carriers demonstrate effective boosting of durable immune responses after retreatment as well as first evidence of clinical efficacy through the absence of advanced adenomas at end of study.

NOUS-209 is an off-the-shelf cancer immunotherapy designed to intercept cancer before it develops. It leverages Nouscom’s proprietary viral vector platform to deliver 209 shared frameshift peptide (FSP) neoantigens found in MSI tumors, training the immune system to recognize and eliminate pre-cancerous and cancerous cells. LS is the most common hereditary cancer syndrome, significantly increasing the lifetime risk of colorectal, endometrial, urothelial, and other cancers. Current preventive management is limited to intensive screening or elective organ removal surgery.

Key Highlights from SITC (Free SITC Whitepaper) 2025 Oral and Poster Presentations:

Durable and Potent Immune Responses: Annual retreatment with NOUS-209 was shown to be safe and to effectively boost long-lived, broad polytopic T cell immunity in LS carriers, with T cells capable of killing tumor cells ex vivo.
First Clinical Evidence of Cancer Interception: While 4.7% of LS participants had advanced adenomas at baseline (which were removed as part of standard of care), no new advanced adenomas were detected after treatment despite an expected annual incidence of around 4%, providing initial evidence of NOUS-209’s cancer preventive efficacy in LS carriers.
Broad Neoantigen Targeting Across Tumor Evolution: Analysis of primary and metachronous colorectal and urothelial MSI tumors confirmed that a high number of FSP neoantigens targeted by NOUS-209 are consistently present, supporting its utility in preventing both first and recurrent cancers in LS patients.

"These results are a step forward in intercepting cancer in LS carriers," said the study’s principal investigator, Eduardo Vilar-Sanchez, M.D., Ph.D., Professor of Clinical Cancer Prevention at The University of Texas MD Anderson Cancer Center. "NOUS-209-induced T cells persist, and annual retreatment was found to be safe, boosting long-term immune protection. The absence of advanced adenomas post-treatment is encouraging."

"These data highlight NOUS-209’s broad applicability beyond colorectal cancer. Its ability to target evolving neoantigens is critical for sustained protection against recurrent LS-associated malignancies," said Toni Seppälä, M.D., Ph.D., Professor of Cancer Research, and chief physician at Tampere University.

"Nouscom’s proprietary viral vector platform is uniquely positioned to deliver rapid, potent, broad and durable immune activation against a large number of shared neoantigens," said Elisa Scarselli, M.D., Chief Scientific Officer of Nouscom. "NOUS-209’s Phase 1b/2 data reinforce our confidence in its ability to safely and effectively prime the immune system for cancer interception in LS carriers."

Marina Udier, Ph.D., CEO of Nouscom concluded, "We are proud to present these compelling data at SITC (Free SITC Whitepaper) 2025 and remain deeply committed to pioneering cancer interception strategies for LS carriers, who deserve a better way to manage their cancer risk. These data, together with the recently presented results of NOUS-209 in MSI-H mCRC patients2 and FDA and EMA alignment, support our commitment to advancing NOUS-209 into a registration-enabling study for cancer interception in Lynch Syndrome carriers."

Oral Presentation Details:

Title: Final Ph1b/2 Results for NOUS-209 Monotherapy in Lynch Syndrome Carriers: Annual Revaccination Boosts T Cell Immunity Informing Future Cancer Interception Strategies

Session: Clinical Oral Abstract Session 2
Date & Time: Saturday, November 8, 2025, 1:45 PM – 3:00 PM ET
Location: Gaylord National Resort & Convention Center, Potomac Ballroom

Poster Presentations Details:

Poster #118 – NOUS-209 Mechanism of Action Validation
Title: NOUS-209 Enables Broad Targeting of Primary and Metachronous Tumors in Lynch Syndrome

Session: Poster Hall
Time: Saturday, November 8, 2025, 9:00 AM – 6:35 PM ET
Location: Prince George’s ABC

Poster #1336 – NOUS-209 Clinical Data
Title: Final Ph1b/2 Results for NOUS-209 Monotherapy in Lynch Syndrome Carriers

Session: Poster Hall
Time: Saturday, November 8, 2025, 9:00 AM – 6:35 PM ET
Location: Prince Georges’ ABC

All abstracts are available on the SITC (Free SITC Whitepaper) website: here

The clinical trial NCT05078866 was supported by the National Cancer Institute of the National Institutes of Health under Award Number UG1CA242609 (project director Dr. Eduardo Vilar-Sanchez). The trial was conducted through the iCAN-PREVENT consortium at The University of Texas MD Anderson Cancer Center, with support from the Data Management, Auditing, and Coordination Center (grant U24CA242637).

(Press release, NousCom, NOV 7, 2025, View Source;utm_medium=rss&utm_campaign=nouscom-presents-new-positive-phase-1-2b-data-of-nous-209-at-sitc-2025-supporting-plans-to-initiate-registration-enabling-study-for-cancer-interception-in-lynch-syndrome-carriers [SID1234659638])