E7046 is a selective small molecule antagonist of the prostaglandin E2 receptor-type-4 that inhibits the differentiation of monocytic myeloid lineage cells towards a pro-tumorigenic phenotype in the TME. This is a first-in-human study of single-agent E7046.
Key eligibility criteria: patients (pts) ≥18 years with selected advanced cancers with high levels of myeloid infiltrate. The dose-escalation phase consisted of 6-pt cohorts of 125, 250, 500, and 750 mg (once-daily, oral, 21-day cycle) doses of E7046. Primary objectives were safety/tolerability, maximum tolerated dose (MTD) and/or RP2D. Secondary objectives included PK and initial anti-tumor activity; exploratory objectives included PD assessments on immune cells in tumor infiltrate and in peripheral blood and metabolic response by 18FDG-PET.
30 pts received E7046 (median age 58 yrs [24-78]; 2-7 lines of prior therapy). Most common tumor types were colorectal cancer (40%), pancreatic cancer (20%), and SCCHN (13%). No DLTs were observed and the MTD was not reached. The most frequent drug-related adverse events (AEs) were diarrhea (20%), decreased appetite, fatigue and nausea (13% each). Drug-related AEs of Gr 3/4 occurred in 4 pts (diarrhea, anaphylactic reaction, hypersensitivity, hyperuricemia, rash, generalized rash). 2 pts had drug-related serious AEs (rash, allergic reaction, fever in 1 pt; hyperuricemia, acute renal failure [Gr 2] in 1 pt). 3 pts discontinued treatment due to AEs (bowel obstruction, allergic reaction, abdominal pain). There were no drug-related deaths. E7046 exposure was dose proportional up to 500 mg with no incremental increase in exposure at 750 mg. E7046 was extensively metabolized, elimination half-life was ∼12hr and accumulation on multiple dosing was ∼2-fold. 2 pts are ongoing and preliminary efficacy showed no objective responses, 4 pts with durable SD or clinically stable (>4 mo) and 4 pts with 18FDG-PET metabolic responses.
Single-agent E7046 was tolerated with no MTD reached in heavily pretreated pts with myeloid-rich tumors. PD analysis of immune cell modulation to help determine the RP2D will be presented at the meeting.
Clinical trial identification
Legal entity responsible for the study
D.S. Hong: Research/Grant Funding: Bayer, Lilly, Genentech, LOXO, Pfizer, Amgen, Mirati, Ignyta, Merck, Daichi-Sanko, Eisai. Travel/Accommodations: MiRNA, LOXO. Consulting/Advisory: Bayer, Baxter, Guidepoint Global. Other interests: Oncoreseponse (founder). L. Reyderman, M. Ren, T. Binder, C.E. Ooi, S. Dayal, O. Ataman: Employee of Eisai Ltd. A. Marabelle: Clinical trial funding from Eisai. Consulting fees from Eisai and Roche. Funding for anti-CSF1R clinical trial from Roche. All other authors have declared no conflicts of interest.