23andMe Holding Co. announced data from its ongoing first-in-human Phase 1/2a clinical trial evaluating the safety and efficacy of 23ME-00610, an investigational antibody targeting CD200R1. Updated data from the now completed dose escalation phase continue to showcase the manageable safety profile of 23ME-00610 at the dose levels tested, and highlight preliminary efficacy results in patients with advanced solid tumors.

The data was presented in two posters at the Society of Immunotherapy in Cancer Annual Meeting 2023 on Friday, November 3, 2023. The poster presentations are available on the 23andMe Therapeutics and Investor websites. The presentations include pharmacokinetic (PK), pharmacodynamic (PD), safety, and efficacy data from 28 patients that enrolled between January 5, 2022 and May 15, 2023 in the dose escalation portion of the 23andMe Phase 1/2 a clinical trial who had received a median of 3 prior anticancer treatment regimens, 54% of whom had prior immunotherapy.

Of the phase 1 patients enrolled across all doses of the dose escalation, there was a 52% stable disease rate. CD200R1 is an exciting new target in the immuno-oncology landscape, and look forward to seeing more results from the ongoing enrollment in disease-specific expansion cohorts. A cohort of adolescents with locally advanced unresectable, or metastatic solid malignancies will also be enrolled.

23ME-00610 is a first-in-class anti-CD200R1 monoclonal antibody in Phase 2 clinical development for advanced solid malignancies that has been shown to rescue T cell function in preclinical studies. CD200R1 was identified as an immuno-oncology (IO) target from the 23andMe database, with pleiotropic causal variants that have opposing effect on risks for cancer and immune diseases, referred to as an IO signature, observed in 3 components in this pathway. Preclinical data indicate that this mechanism has the potential to restore the ability for both T-cells and myeloid cells to kill cancer cells.