Compugen Ltd. updated data from its Phase 1 dose escalation and expansion study of COM701 as a monotherapy, and in a dose escalation combination study with Opdivo® (nivolumab). COM701 and Opdivo® combination arm dose escalation: In 15 evaluable patients, COM701 in combination with Opdivo® was well-tolerated with no reported dose-limiting toxicities up to the fifth and final dose cohort of COM701 20 mg/kg and Opdivo® 480 mg, both IV Fourth Quarter weeks. The disease control rate (DCR) was 66.7% (N=10) with best responses of complete response (CR) 6.7% (N=1), partial response (PR) 6.7% (N=1) and stable disease (SD) 53.3% (N=8). Previously reported patient with anal squamous cell carcinoma with confirmed CR remains on treatment at 96 weeks (22 months). This patient had three prior lines of therapy and enrolled within one month after progression on Opdivo® monotherapy. Previously reported patient with renal cell carcinoma with best response of SD remains on treatment at 75 weeks. A patient with microsatellite stable (MSS)-colorectal cancer with durable confirmed partial response previously reported at AACR 2020 remained on study treatment for 44 weeks. COM701 monotherapy arm: Overall 36 patients enrolled. 16 patients, all comers in dose escalation and 20 patients in dose expansion; four patients of each: endometrial cancer, NSCLC, ovarian cancer, breast cancer and colorectal cancer (MSS). The disease control rate (DCR) was 47.2% (N=17) with best responses of partial response (PR) 2.7% (N=1) and stable disease (SD) 44.4% (N=16). Previously reported patient with primary peritoneal cancer (platinum resistant, MSS) with confirmed PR remains on study treatment at 79 weeks (18 months). Patient had three prior lines of standard-of-care treatment. Archival pre-treatment biopsy data revealed the patient was PD-L1 negative, with PVRL2 expression on tumor and endothelial cells, with an immune desert phenotype (i.e, no immune cells detected prior to treatment). Peripheral blood assessment showed immune activation as measured by immune cell proliferation and IFN? induction prior to tumor shrinkage. Demonstrated durable antitumor activity in extensively pretreated population: Durable responses to treatment (CR, PR or SD = 6 months) in 10/51 (19%) patients. Best responses of CR, PR, or SD were observed in 11/21 (52%) patients with prior treatment refractory disease. Best response of CR, PR or SD were observed in 13/18 (72%) patients with prior treatment with immune checkpoint inhibitors. Preliminary biomarker results demonstrate immune activation with COM701 treatment: Peripheral pharmacodynamic changes were measured via immune cell proliferation and cytokine levels in peripheral blood before and on treatment. After one treatment cycle, patients treated with COM701 monotherapy showed a trend of increased proliferation of effector memory CD8+ T cells (average change 87%), an immune cell population that expresses high level of PVRIG and are critical in driving anti-tumor immunity. Similar results were observed in the combination arm. Proliferation of NK-T cells, an immune cell population that expresses high level of PVRIG and plays a role in antitumor activity, increased significantly one day after COM701 monotherapy treatment, with a similar trend observed in the combination arm. Levels of IFN?, a cytokine which plays a key role in antitumor immunity, were upregulated following combination treatment of COM701 with Opdivo®, with a dose response trend with increasing doses of COM701, suggesting the observed activity is derived from the combination treatment and not Opdivo® alone. Anti-tumor activity was observed in PD-L1 low, PVRL2 positive patients, suggesting COM701 treatment may drive anti-tumor immunity even in patients with less inflamed tumor microenviroment.