Riboscience to Present First Overall Survival and Immune Activation Data from Phase 1b Study of ENPP1 Inhibitor RBS2418 as Monotherapy and in Combination in Advanced Metastatic Cancers Including MSS CRC, at ESMO 2026

PALO ALTO, Calif., Oct. 19, 2026 /PRNewswire/ -- Riboscience, a clinical-stage biotechnology company developing first-in-class immunotherapies, today announced that Phase 1b data for RBS2418, its lead oral ENPP1 inhibitor, will be presented in a poster at the European Society for Medical Oncology (ESMO) Congress 2026, held October 23–27 in Madrid, Spain.

ESMO 2026 Poster Presentation Details

• Title: Overall survival and intratumoral immune activation in subjects with advanced metastatic solid tumors, by Thomas U. Marron, Jamal G. Misleh, Michael Gordon, Zev A. Wainberg, Christopher T. Chen, Daniel Johnson, Alexander I. Spira, Jordan Berlin, Won Jin Ho, John T. Hamm, Ralph V. Boccia, Seol Hee Im, Stephan Rogalla, Juergen Schanzer, Ningwu Huang, Sayantanee Paul, Edward Pham, Buer Song, Jeffrey S. Glenn, Hirak Der-Torossian, Klaus Klumpp and Aaron J. Scott
• Abstract/Poster Number: 1977P
• Session: Investigational Immunotherapy
• Date/Time: Saturday, October 24, 2026, 12:00 CEST
• Location: IFEMA Madrid, Hall 5

The poster will present safety, pharmacokinetic, pharmacodynamic and clinical outcome data, including overall survival, from the Phase 1 study of RBS2418 (NCT05270213) in patients with advanced unresectable, recurrent or metastatic solid tumors (safety population n=89). Results will feature outcomes in the overall population and in RBS2418 monotherapy and colorectal cancer (CRC) cohorts. The study evaluates RBS2418 alone and with approved anti-cancer treatments.

"As the first ENPP1 inhibitor in the clinic, RBS2418 is bringing a new type of immunotherapy to the field. Seeing immune activation in cold tumors from a simple oral monotherapy is very exciting, and we are proud to share our first long-term survival outcomes at ESMO." said Klaus Klumpp, Co-founder and President of Riboscience."

About RBS2418

RBS2418 is a first-in-class oral small-molecule inhibitor of ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1). It binds ENPP1 with picomolar affinity and high selectivity. The expression of ENPP1 and cGAS is highly prevalent in solid tumors and ENPP1 is associated with effective cGAMP clearance in the tumor microenvironment (TME), a block of dendritic cell activation, a cold tumor phenotype and immune evasion. ENPP1 expression on circulating tumor cells has been associated with an increased risk of metastasis. By blocking ENPP1, RBS2418 is designed to restore anti-tumor immunity. RBS2418 is being studied in a Phase 1a/b trial in advanced solid tumors, as monotherapy in a Phase 2 trial for late-line CRC (NCT06824064), and in combination with the STRIDE (Single Tremelimumab Regular Interval Durvalumab) regimen for first-line heptaocellular carcinoma (HCC) (NCT07175441).

About Riboscience
Riboscience is a privately held, clinical-stage biotechnology company based in the San Francisco Bay Area. The company uses its proprietary library of nucleoside and non-nucleoside analogs and structure-guided design to develop selective drug candidates for cancer, joint and infectious disease. For more information, visit www.riboscience.com.

Contact
Klaus Klumpp
Co-founder and President, Riboscience
[email protected]

SOURCE Riboscience LLC