Abstract 2548: Preclinical development of EARLI-001, a genetic platform producing cancer-activated synthetic biomarkers for the early detection of malignancies

Abstract

Abstract Early detection of cancer is a powerful driver of increased survival rate, quality of life and reduced healthcare costs. ‘Liquid biopsies' that rely upon chemistry for the detection of blood-based endogenous cancer biomarkers such as proteins, circulating tumor DNA or RNA show only limited sensitivity for certain early stage cancers where the tumor mass shedding those biomarkers is smaller. Rather than searching for elusive natural biomarkers shed into the bloodstream, we are employing a promising alternate approach rooted in biology to usurp the highly dysregulated transcriptional pathways that give rise to malignancies to force cancer cells to produce easily detectable ‘synthetic' biomarkers that do not naturally occur. EARLI-001 is a DNA nanoplasmid comprised of a cancer-activated promoter to drive expression of Secreted Embryonic Alkaline Phosphatase (SEAP). The survivin promoter was initially selected for proof of concept because the corresponding anti-apoptotic gene product is widely overexpressed in many cancers, including melanoma, liver, breast, lung, colon and ovarian cancer, while not being expressed in normal adult tissues. The synthetic biomarker SEAP is a secreted variant of human placental alkaline phosphatase, which is only expressed during fetal development and thus has near-zero background in adult blood. EARLI-001 is formulated using a non-viral linear polyethyleneimine and administered intravenously to enable broad tissue distribution and transient transfection of multiple tissues. The sensitivity and specificity of EARLI-001 for tumor detection were established using a variety of cell-derived xenograft models. A single administration of EARLI-001 in immunocompromised mice bearing a modest burden of lung metastases drove cancer-activated SEAP expression that was at least 100-fold higher than the corresponding expression in non-tumor bearing animals. In an immune-competent syngeneic model, EARLI-001 produced 10-fold higher SEAP expression in mice bearing lung metastases of 4T1 mammary tumor cells than naïve mice. EARLI-001 could also discriminate mice bearing orthotopic Hep3B liver xenograft tumors from naïve control mice. Finally, the sensitivity of EARLI-001 in detecting small tumors was demonstrated in a longitudinal study, in which robust cancer-specific SEAP expression occurred even when the lung tumor burden was too low to result in significant changes in organ weight. The toxicology, pharmacokinetics, and biodistribution of EARLI-001 were evaluated in several GLP studies in mice as well as canines, enabling translation to a first-in-man clinical study. This Phase 1 dose escalation study will evaluate the safety, tolerability and PK/PD of EARLI-001 in subjects with locally advanced or metastatic lung cancer and enable further clinical development of the cancer-activated synthetic biomarker platform. Citation Format: Badriprasad Ananthanarayanan, Regina Nieu, Evan Bishop, Shireen Rudina, Alex Harwig, Bijee George, David Suhy. Preclinical development of EARLI-001, a genetic platform producing cancer-activated synthetic biomarkers for the early detection of malignancies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2548.