OncoResponse, a clinical-stage biotech company advancing immunotherapies derived from the immune systems of Elite Cancer Responders, today announced the results of the Phase 1 trial of OR502, a novel, humanized anti-leukocyte immunoglobulin like receptor B2 (LILRB2) antibody that rescues innate and adaptive immune responses from LILRB2 mediated immune suppression. The Phase 1 study was designed to determine the safety, tolerability, and preliminary anti-tumor activity of OR502 administered as a monotherapy and in combination with anti-PD-1 in subjects with advanced solid tumors.

“We are pleased that OR502 has demonstrated an excellent safety profile and compelling early efficacy signals. OR502 was well tolerated up to the highest dose level with no DLTs, SAEs or Grade ≥ 3 treatment-related AEs. The study showed promising early efficacy signals in monotherapy, including 2 PR and 9 SD (N=17) for a disease control rate of 65%. We are excited to conduct the next phase of clinical studies, which will evaluate OR502 in two mini-cohorts of patients, including cutaneous melanoma and NSCLC.

“Completing this Phase 1 study reflects our ongoing commitment to develop impactful treatments to improve outcomes for cancer patients,” said Clifford Stocks, Chief Executive Officer of OncoResponse.

“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. “OncoResponse has spent years devising strategies to block or reprogram tumor associated macrophages to drive anti-tumor activity. We are excited by the vast promise of OR502 with preclinical and initial clinical data showing superiority over other anti-LILRB2 antibodies.”

About the Phase 1 Trial
This Phase 1 study was an open-label, multicenter, first-in-human dose-escalation and expansion study designed to determine the safety, tolerability, and preliminary anti-tumor activity of OR502, a fully human IgG1 antibody that binds specifically to LILRB2. OR502 will be administered as a monotherapy and in combination with anti-PD-1, cemiplimab, in subjects with advanced solid tumors. The study consists of two parts. Part A of the study was a dose-escalation phase to determine the maximum-tolerated dose (MTD) or optimal dose of OR502 for further evaluation as monotherapy and in combination. Part B is an expansion phase in subjects with advanced solid tumors treated with OR502 at two separate doses, to help determine the recommended Phase 2 dose (RP2D) for further development and determine preliminary anti-tumor activity. The role of potential biomarkers will be evaluated throughout the study, and more intensively in a separate biology cohort. Additional details are available on ClinicalTrials.gov, identifier: NCT06090266.

About OR502
LILRB2 is an immunoinhibitory receptor expressed on tumor-associated macrophages (TAMs) found in the tumor microenvironment (TME). TAMs inhibit the activity of checkpoint inhibitor (CPI) therapy and prevent T cells from killing tumors. Blocking the inhibitory activity of TAMs and promoting the activity of tumor-killing T cells reverses inhibition of CPI therapy, potentially leading to more and deeper responses to CPIs in patients. This is the mechanism of OR502, which modulates LILRB2 by blocking its engagement of HLA-G on tumor cells and prevents the suppression of the myeloid cells. Elevated expression of LILRB2 correlates with reduced patient survival in various tumor types. Our humanized monoclonal antibody, OR502, targets LILRB2 and blocks the inhibitory activity of TAMs and promotes the activity of tumor-killing T cells, reversing inhibition of CPI therapy.

About OncoResponse
OncoResponse is a clinical-stage, immuno-oncology biotech company developing cancer immunotherapies using clues from the immune systems of Elite Cancer Responders. In a broad strategic alliance with MD Anderson Cancer Center, OncoResponse deploys a proprietary B-cell discovery platform to identify and develop novel antibodies targeting immune cells in the tumor microenvironment. The company’s lead clinical candidate, OR502 is a best-in-class anti-LILRB2 antibody that rescues innate and adaptive immune responses from LILRB2-mediated immune suppression and entered clinical study in 2023. For more information, please visit www.oncoresponse.com and follow us on LinkedIn and X.