23andMe Therapeutics Reports Phase 2 Results for Two Cancer Cohorts and Biomarker Data from 23ME-00610 Study

23andMe Holding Co. (Nasdaq: ME), a leader in human genetics and biopharmaceuticals, has unveiled promising preliminary data from its Phase 1/2a clinical trial of 23ME-00610, presented at the European Society of Medical Oncology (ESMO) Congress 2024 in Barcelona. The study focused on two new patient cohorts, including those with clear-cell renal-cell carcinoma (ccRCC) and patients with tumors exhibiting high mutational burden (TMB-H) or microsatellite instability-high (MSI-H).

The data highlighted a confirmed partial response in a patient with ccRCC, showing a 38% reduction in tumor size. The study also noted higher expression levels of CD200 on tumors correlated with increased clinical benefit from the treatment, suggesting these could serve as biomarkers for patient selection. Additionally, a more pronounced response was observed in patients with "cold" tumors, indicating potential for patients who do not respond to PD-1/PD-L1 inhibitors.

23andMe's therapeutic arm presented three posters summarizing the results for 23ME-00610. One poster covered 10 patients with ccRCC, another focused on 13 patients with TMB-H or MSI-H cancers, and a third poster reviewed data from 118 participants in the broader Phase 1/2a trial. This comprehensive data supplements earlier findings from cohorts with neuroendocrine and ovarian cancer presented at the American Society of Clinical Oncology Meeting in 2024.

Dr. Jennifer Low, Head of Therapeutics Development at 23andMe, expressed optimism about the therapeutic potential demonstrated by the study. She emphasized the potential of CD200 expression as a biomarker to select patients who might benefit the most from this novel treatment. According to Dr. Low, interrupting the CD200/CD200R1 pathway could significantly reverse immune suppression in tumors, providing new hope for patients who have not responded to multiple lines of treatment, including existing checkpoint inhibitors.

23ME-00610 is designed as an IgG1 antibody to reverse immunosuppression by blocking the interaction between CD200 on tumor cells and CD200R1 on immune cells. Preclinical studies have shown that this mechanism restores T cell activity and targets CD200-expressing tumor cells effectively. The CD200R1 pathway was identified as a critical checkpoint inhibition pathway, supported by genetic data linking it to cancer and immune diseases, referred to by 23andMe as an immuno-oncology signature.

Key findings from the ccRCC cohort include a confirmed partial response in a 61-year-old male with high CD200 tumor expression, ongoing treatment for over 32 weeks, and an acceptable safety profile of 23ME-00610. Adverse events were mild, including dry mouth and nausea, and no serious adverse events led to discontinuation or dose interruption. Preliminary data also suggested that patients with highly vascularized tumors and high CD200 levels may benefit more from this treatment.

In the TMB-H/MSI-H cohort, 13 adult patients received a median of five prior treatments and were administered 23ME-00610 for up to 11 cycles. One patient continues to be treated as of the last data cutoff.

Across 118 participants in the broader Phase 1/2a trial, higher CD200 expression on tumor cells and certain genetic markers were associated with better outcomes, suggesting potential for using these biomarkers in patient selection in future studies. Analysis of tumor samples before and during treatment indicated an increase in immune cell markers and interferon genes, supporting the immune-modulating effects of the treatment.

23ME-00610 leverages genetic insights from 23andMe's extensive database to target the CD200/CD200R1 pathway, aiming to enhance immune responses against tumors. Initial clinical data indicate favorable pharmacokinetics and a promising safety profile for this novel therapy, potentially in combination with other treatments.

23andMe continues to pioneer advancements in genetics-led healthcare and biopharmaceuticals, aiming to empower a healthier future through innovative treatments and comprehensive genetic data analysis.