Dostarlimab Delivers Durable Survival in RUBY Trial

In an interview during 2026 SGO Annual Meeting, Matthew Powell, MD, discussed the long-term outcomes of the landmark RUBY trial and what the latest data mean for patients with advanced endometrial cancer.

Powell began by reflecting on the initial 2023 results of the RUBY trial, which evaluated the addition of dostarlimab to standard chemotherapy with carboplatin and paclitaxel. At the time, the study demonstrated a substantial improvement in progression-free survival, particularly among patients with defective mismatch repair tumors. In this subgroup, the hazard ratio for progression-free survival was approximately 0.3, signaling a dramatic reduction in the risk of disease progression.

Importantly, overall survival data were also highly encouraging. In the dMMR population, the median overall survival had not yet been reached, underscoring the depth and durability of response with the immunotherapy-based combination. Even among patients with proficient mismatch repair disease—historically more difficult to treat—the addition of dostarlimab resulted in a meaningful improvement, extending survival by approximately seven months while maintaining quality of life.

With more than four years of follow-up now available, Powell emphasized that the durability of benefit has become even more striking. In the dMMR subgroup, only four patients experienced disease progression over the past two and a half years, a remarkable outcome in advanced endometrial cancer. These findings translate to a 66% reduction in the risk of death, reinforcing the long-term impact of this therapeutic approach.

Powell noted that these sustained outcomes are critical as clinicians evaluate frontline treatment strategies. The consistency of benefit over time supports the integration of immunotherapy into standard regimens, particularly for biomarker-selected populations. As the data continue to mature, the RUBY trial stands as a clear example of how combining immunotherapy with chemotherapy can meaningfully alter the disease trajectory.

Overall, the updated results highlight not only improved survival but also lasting disease control, marking a significant advancement in the treatment of advanced endometrial cancer and offering new optimism for patients and providers alike.