OncoResponse's OR502 Demonstrates Promising Safety and Efficacy in Phase I Solid Tumor Trial

Key Insights

• OncoResponse's Phase I trial of OR502, a humanized anti-LILRB2 antibody, shows a promising safety profile in patients with advanced solid tumors, with no dose-limiting toxicities reported.
• The trial indicated early efficacy signals of OR502 as a monotherapy, achieving a 65% disease control rate with two partial responses and nine cases of stable disease out of 17 subjects.
• OR502 is being advanced into further trials, including mini-cohorts for cutaneous melanoma and non-small cell lung cancer, to evaluate its potential in overcoming resistance to CPI therapy.

OncoResponse has announced positive outcomes from its Phase I clinical trial evaluating OR502, a humanized anti-leukocyte immunoglobulin-like receptor B2 (LILRB2) antibody, in patients with advanced solid tumors. The study, a multicenter, two-part, open-label, first-in-human trial, assessed the safety, tolerability, and preliminary anti-tumor activity of OR502 both as a monotherapy and in combination with cemiplimab, an anti-programmed cell death protein (PD-1) inhibitor.

Phase I Trial Design and Results

The Phase I trial consisted of two parts: a dose-escalation phase (Part A) to determine the maximum tolerated dose (MTD) or optimal dose, and an expansion phase (Part B) to establish the recommended Phase II dose (RP2D) and further evaluate anti-tumor activity. In Part B, subjects with advanced solid tumors were treated with two separate doses of OR502.

The trial findings indicated a favorable safety profile for OR502, with no dose-limiting toxicities (DLT) or significant adverse events reported, even at the highest dose levels. As a monotherapy, OR502 exhibited promising early efficacy signals, including two partial responses (PR) and nine cases of stable disease (SD) out of 17 subjects, resulting in a 65% disease control rate.

Future Development Plans

OncoResponse plans to advance OR502 into further clinical trials, with a focus on evaluating the antibody in mini-cohorts of patients with cutaneous melanoma and non-small cell lung cancer (NSCLC).

Expert Commentary

According to OncoResponse chief scientific officer Kamal Puri, OR502 binds to LILRB2 in a unique way, reversing immunosuppression in cancer and offering a potential treatment option for patients who have struggled with CPI therapy effectiveness. Puri added, "OncoResponse has spent years devising strategies to block or reprogramme tumour-associated macrophages to drive anti-tumour activity. We are excited by the vast promise of OR502 with preclinical and initial clinical data showing superiority over other anti-LILRB2 antibodies."

Collaboration with Regeneron

In September 2022, OncoResponse entered into a clinical supply agreement with Regeneron for Libtayo (cemiplimab), a PD-1 inhibitor, which was used in combination with OR502 in the Phase I trial.