158P Triple blockade of the DNAM-axis with COM701 + BMS-986207 + nivolumab demonstrates preliminary antitumor activity in patients with platinum-resistant OVCA

Treatment [tx] options for platinum-resistant ovarian cancer [PROC] are limited [ltd]. Immune checkpoint inhibitors (ICI) have ltd activity in PROC. Clinical studies evaluating novel therapies are urgently needed. COM701, a novel, 1st in-class ICI binds to PVRIG, leading to activation of T-cells. BMS-986207 is an ICI blocker of TIGIT. We reported a partial response [PR] with COM701 monotherapy in a pt with primary peritoneal CA1. We hypothesized that in pts with PROC, blocking the DNAM axis with the triplet: COM701 + BMS-986207 + nivolumab, would demonstrate antitumor activity with a favorable safety and tolerability profile. We present preliminary results. All 20 pts enrolled received COM701 20 mg/kg + BMS-986207 480 mg + nivolumab 480 mg IV Q4W. Primary objectives [obj] were safety/tolerability; secondary obj of antitumor activity. Key inclusion criteria: Age ≥ 18 yrs, histologically confirmed advanced malignancies and exhausted all available standard tx. Key exclusion criteria: prior receipt of any inhibitor of PVRIG, TIGIT, or PD-1/PD-L1. Investigator assessed responses per RECIST v1.1, safety per CTCAE v5.0. Median [med] age 61yr, med follow-up 51 days [range 1-202], med number of prior lines of therapy - 4 [range 1-10]. Objective response rate 4/20 [20%] pts [all ongoing study tx, 3 confirmed PR], 3 PRs - serous adenoCA, 1 PR - clear cell histology. No complete responses (CR); 4pts with stable disease (SD), disease control rate [CR+PR+SD] 8/20 [40%]. Most frequent [freq] histology - serous adenoCA 10/20 [50%], clear cell 3/20 [15%]. Most freq AE G1/2 fatigue in 11 pts. A sustained immune activation induced by the tx, with a maximum 7.6-fold average increase of peripheral IFNɣ in 16pts evaluated [p<0.005]. The combination of COM701 + BMS-986207 + nivolumab has encouraging signal of antitumor activity with immune activation in pts with heavily pre-treated PROC and is well tolerated. Additional data will be presented at the conference. Data extract 08/29/2022. 1. Vaena D et al, COM701±nivolumab: Results of an ongoing P1 study of safety, tolerability & preliminary antitumor activity in pts with advanced solid malig. J Clin Onco 39, 2021 (suppl 15; abst 2504).