Elevation Oncology's EO-3021, a novel antibody-drug conjugate (ADC), has received Fast Track designation from the U.S. Food and Drug Administration (FDA) for the treatment of patients with advanced or metastatic gastric and gastroesophageal junction (GEJ) cancer expressing Claudin 18.2 that has progressed on or after prior therapy. This designation aims to accelerate the development and review of EO-3021, addressing a significant unmet medical need in patients with these cancers.
Mechanism of Action and Clinical Development
EO-3021 is designed to target Claudin 18.2, a protein typically found in gastric epithelial cells but exposed during malignant transformation due to disruption of tight junctions. The ADC comprises an immunoglobulin G1 (IgG1) monoclonal antibody targeting Claudin 18.2, linked to a monomethyl auristatin E (MMAE) payload via a cleavable linker, resulting in a drug-to-antibody ratio (DAR) of 2. This specific design aims to deliver a cytotoxic payload directly to cancer cells expressing Claudin 18.2, minimizing off-target effects.
Currently, EO-3021 is being evaluated in an open-label, international, multicenter, Phase 1 study (NCT05980416) involving adult patients with solid tumors likely to express CLDN18.2, including gastric, GEJ, pancreatic, and esophageal cancers. The study includes dose escalation and expansion phases to determine the optimal dose and assess the safety and preliminary efficacy of EO-3021.
Early Clinical Data
Initial data from the Phase 1 trial, with a cutoff date of June 10, 2024, indicated that EO-3021 was generally well-tolerated. In the safety population (n = 32), no grade 4 or 5 treatment-related toxicities were observed, and fewer than 10% of patients discontinued the drug due to adverse effects (AEs). Common treatment-emergent AEs included nausea (56%), reduced appetite (47%), fatigue (41%), and diarrhea (28%).
Efficacy findings revealed that in patients with gastric and GEJ cancer and claudin 18.2 expressed in 20% or more of tumor cells at immunohistochemistry (IHC) 2+/3+ (n = 7), EO-3021 elicited an objective response rate (ORR) of 42.8%, including three confirmed partial responses. The disease control rate (DCR) was 71.4%.
Fast Track Designation Significance
The FDA's Fast Track designation is designed to expedite the development and review of drugs that treat serious conditions and fill unmet medical needs. This designation provides Elevation Oncology with opportunities for more frequent interactions with the FDA to discuss the development plan and eligibility for priority review and accelerated approval based on clinical data.
Joseph Ferra, President and CEO of Elevation Oncology, stated, "We are delighted to receive Fast Track designation for EO-3021, which marks an encouraging recognition of the unmet medical need in patients with Claudin 18.2-expressing tumors, as well as the potential for EO-3021 to deliver improved therapeutic outcomes." He also noted that early results from the Phase 1 trial showed a confirmed overall response rate of 42.8% in a Claudin 18.2-enriched subset of gastric and GEJ cancer, with differentiated tolerability and minimal MMAE-associated toxicities.
Future Development Plans
Elevation Oncology plans to advance EO-3021 through monotherapy dose expansion and report additional data from the ongoing trial in the first half of 2025. The company also intends to initiate a combination portion of the study later this year, exploring EO-3021 in combination with ramucirumab in the second-line treatment of metastatic gastric or GEJ cancer and with dostarlimab in the first-line setting.
About Gastric and GEJ Cancers
Gastric and gastroesophageal junction cancers are aggressive malignancies with often poor prognoses, especially in advanced stages. The identification of Claudin 18.2 as a relevant target has opened new avenues for therapeutic intervention, and EO-3021 represents a promising approach to improve outcomes for patients with these cancers.
