Nouscom’s cancer vaccine shows potential with Lynch Syndrome

Nouscom, a clinical-stage immuno-oncology company developing off-the-shelf and personalized viral vector based cancer vaccines, today announced that promising interim data from a Phase 1b trial evaluating NOUS-209 in Lynch Syndrome (LS) carriers was published in a Late-breaking Abstract and will be presented in an oral abstract presentation at the Society for Immunotherapy of Cancer (SITC) Annual Meeting in San Diego, USA.

NOUS-209 is an off-the-shelf cancer vaccine encoding 209 neoantigens that are shared across both sporadic and hereditary Microsatellite Instable (MSI) tumors. Patients with LS carry a high-risk hereditary predisposition to developing MSI tumors, and once diagnosed, carriers are encouraged to have routine colonoscopy and endoscopy screenings with the potential of surgery currently as the primary treatment option.

In this single-arm, open-label preventive Phase 1b study (NCT05078866), NOUS-209 monotherapy was found to be safe, well tolerated and able to generate potent and broad immunogenic T cell responses in the first 10 LS participants recruited. The study was led by researchers at The University of Texas MD Anderson Cancer Center, in collaboration with the Cancer Prevention Clinical Trials Network and sponsored by the National Cancer Institute.

NOUS-209 is also being evaluated in ongoing and actively enrolling randomized Phase 2 clinical trials (NCT04041310) in combination with checkpoint inhibitors in patients with metastatic MSI tumors.

As of date of interim data cutoff, no serious adverse events were observed following intramuscular administration of NOUS-209. Vaccination with NOUS-209 is considered safe and well tolerated, with rapid resolution of local and systemic reactogenicity. NOUS-209 immunogenicity has been tested and demonstrated through ex-vivo interferon-gamma ELISpot assay in 100% of tested LS subjects (n=10 out 10 subjects), with no immune responses detectable prior to NOUS-209 administration. Vaccine-induced responses were broad and recognized multiple different neoantigens, potently inducing both CD4 and CD8 T cell responses. The Phase 1b study is enrolling up to 45 LS subjects across multiple US sites and is expected to be fully enrolled by early 2024.

Dr Eduardo Vilar-Sanchez, M.D., Ph.D., Professor of Clinical Cancer Prevention, at MD Anderson and Principal Investigator on the study, said: “The work of the Cancer Prevention Clinical Trials Network is to support early trials that may give LS patients a new way to intercept cancer and possibly lower their cancer risk over time. The presented data suggest that a novel vaccine such as NOUS-209 could provide a compelling approach for cancer interception in LS carriers.”

Dr Elisa Scarselli, Chief Scientific Officer of Nouscom added: “These first data demonstrate that NOUS-209 monotherapy can potently and broadly stimulate the immune system in LS subjects, so as to be ready to intercept the development of MSI tumors at an early stage. We are deeply indebted to all our collaborators at the NCI and LS trial volunteers, who collectively are highly motivated in our goal to intercept cancer.”

Dr Richard Davis, Chief Operating Officer of Nouscom, commented: “These data are a testament to the power of a true collaboration between industry and academia in our shared ambition to intercept cancer before it can take hold for the huge numbers of LS carriers. We look forward to reporting the full Phase 1b results and outlining the next steps in initiating randomized Phase 2 trials next year.”

About Lynch Syndrome
Lynch Syndrome (LS) affects approximately 1 in 300 people and is one of the most common hereditary cancer syndromes, with carriers at high risk of developing microsatellite instability (MSI) cancers, including colorectal or endometrial cancers. LS is caused by mutations in one of the four DNA mismatch repair (MMR) genes that as a result lead to tumors accumulating large number of neoantigens. Vaccine-based strategies to target neoantigens, such as NOUS-209, are being explored in their ability to stimulate the immune system to recognize and intercept tumors at their early stages of development.