XUANZHUBIO-B (02575): The phase III clinical study data of Palbociclib as a first-line treatment for HR+/HER2- advanced breast cancer will be presented at ESMO in 2025.

XUANZHUBIO-B(02575) announced that it presented the analysis results of the Phase III clinical trial (BRIGHT-3) of palbociclib combined with letrozole or anastrozole in the first-line treatment of HR+/HER2- advanced breast cancer in the form of a poster at the European Society for Medical Oncology (ESMO) 2025 held in Germany on October 20, 2025. The BRIGHT-3 study is a randomized, double-blind Phase III clinical trial conducted in 58 centers in China to evaluate the efficacy and safety of palbociclib combined with letrozole or anastrozole in the first-line treatment of HR+/HER2- advanced breast cancer. The study included a total of 397 patients with HR+/HER2- advanced breast cancer, with 55.7% of patients having visceral metastasis and 41.3% being newly diagnosed in advanced stage. As of January 10, 2025, the median follow-up time was 20.7 months. The interim analysis results showed that, in terms of efficacy, the median progression-free survival (mPFS) for the palbociclib group evaluated by investigators and an independent review committee did not reach the endpoint, with values of 18.43 months and 19.55 months for the control group. The mPFS did not reach the endpoint, indicating that more patients in the palbociclib group have not experienced disease progression, showing its durable efficacy advantage. Compared to placebo combined with endocrine therapy, the palbociclib regimen reduced the risk of disease progression or death by 47%, and particularly in patients with poor prognosis such as liver metastasis, the risk of disease was reduced by 64%, demonstrating its outstanding potential in difficult-to-treat populations. In the intention-to-treat population, the objective response rate (ORR) for the palbociclib group was 63.5%, significantly higher than the 42.5% in the control group. In terms of safety, the common adverse events associated with palbociclib combination therapy (such as diarrhea, neutropenia, etc.) were mostly grades 1-2, manageable through supportive care or dose adjustments, indicating overall manageable safety. Based on the interim data from the BRIGHT-3 study, the Chinese National Medical Products Administration formally accepted the new drug application for palbociclib combined with aromatase inhibitors (AI) for the treatment of HR+/HER2- advanced breast cancer on May 14, 2025. Palbociclib tablets (trade name: XUANYUENING) is a novel CDK2/4/6 inhibitor with a unique multi-target synergistic mechanism of action, effectively inhibiting tumor cell proliferation and significantly reducing the hematologic toxicities commonly associated with traditional CDK4/6 inhibitors. Palbociclib was approved by the Chinese National Medical Products Administration on May 13, 2025 for use in combination with fulvestrant in patients who have experienced disease progression after prior endocrine therapy, and as a monotherapy in patients who have experienced disease progression after receiving two or more prior endocrine therapies in the metastatic stage and one prior chemotherapy, becoming the first and only CDK4/6 inhibitor with approved monotherapy indication in China.