OncoResponse, a clinical-stage biotech company, has announced the results of its Phase 1 trial of OR502, a novel, humanized anti-leukocyte immunoglobulin like receptor B2 (LILRB2) antibody. The study, designed to assess the safety, tolerability, and preliminary anti-tumor activity of OR502 as a monotherapy and in combination with anti-PD-1 therapy in subjects with advanced solid tumors, showed promising early efficacy signals and a favorable safety profile.
The Phase 1 study was an open-label, multicenter, first-in-human dose-escalation and expansion study. It consisted of two parts: a dose-escalation phase (Part A) to determine the maximum-tolerated dose (MTD) or optimal dose of OR502, and an expansion phase (Part B) to determine the recommended Phase 2 dose (RP2D) and preliminary anti-tumor activity.
Promising Efficacy and Safety Profile
According to OncoResponse, OR502 demonstrated an excellent safety profile, being well-tolerated up to the highest dose level with no dose-limiting toxicities (DLTs), serious adverse events (SAEs), or Grade ≥ 3 treatment-related adverse events (AEs). The study also revealed promising early efficacy signals in monotherapy, including 2 partial responses (PR) and 9 cases of stable disease (SD) out of 17 patients, resulting in a disease control rate of 65%.
"We are pleased that OR502 has demonstrated an excellent safety profile and compelling early efficacy signals," said Clifford Stocks, Chief Executive Officer of OncoResponse. "Completing this Phase 1 study reflects our ongoing commitment to develop impactful treatments to improve outcomes for cancer patients."
Mechanism of Action
OR502 functions by targeting LILRB2, an immunoinhibitory receptor expressed on tumor-associated macrophages (TAMs) within the tumor microenvironment (TME). TAMs can inhibit the activity of checkpoint inhibitor (CPI) therapy and prevent T cells from effectively killing tumor cells. By blocking the interaction of LILRB2 with HLA-G on tumor cells, OR502 aims to reverse immunosuppression and promote anti-tumor activity.
"OR502 binds to LILRB2 in a unique way to reverse immunosuppression in cancer and offers a potential treatment option to patients who have otherwise struggled with CPI therapy effectiveness," said Kamal Puri, PhD, Chief Scientific Officer of OncoResponse.
Next Steps
OncoResponse is planning to conduct the next phase of clinical studies, which will evaluate OR502 in two mini-cohorts of patients, including those with cutaneous melanoma and non-small cell lung cancer (NSCLC). These studies aim to further explore the potential of OR502 in specific cancer types and refine the recommended Phase 2 dose.
Additional details about the Phase 1 trial can be found on ClinicalTrials.gov, identifier: NCT06090266.
