Phase 2 Study of BEBT-209 Plus Gemcitabine and Carboplatin in Metastatic TNBC

Metastatic triple-negative breast cancer (TNBC) presents significant challenges because of its aggressive nature and limited treatment options. This phase 2 study evaluated BEBT-209, a potent CDK4 inhibitor, combined with gemcitabine and carboplatin in patients with early relapse (<12 months postadjuvant therapy) or prior systemic therapy for metastatic TNBC.

Among early-relapse patients treated with BEBT-209 in combination with gemcitabine and carboplatin (n=13), the objective response rate (ORR) was 38.5% (95% confidence interval [CI], 13.9-68.4) and the median progression-free survival (PFS) was 7.1 months (95% CI, 4.1-9.6). For patients with 1 to 2 prior lines of metastatic therapy (n=23), the ORR was 43.5% (95% CI, 19.7-61.5), and the median PFS was 6.7 months (95% CI, 4.4-9.6). These outcomes surpassed historical benchmarks for sacituzumab govitecan (31% ORR, 4.8-month median PFS) and conventional chemotherapy (4% ORR, 1.7-month median PFS).

The most common grade 3 to 4 hematologic toxicities were leukopenia (68%), neutropenia (68%), thrombocytopenia (34%), and anemia (18%). BEBT-209 was well tolerated, with toxicity profiles consistent with the gemcitabine and carboplatin regimen.

BEBT-209 in combination with gemcitabine and carboplatin demonstrated encouraging efficacy and manageable toxicity, offering a potential breakthrough therapy for metastatic TNBC. A global phase 3 trial is planned to further confirm these findings.

Source: Ouyang Q, et al. Efficacy and safety of BEBT-209, a primary CDK4 inhibitor, in combination with gemcitabine and carboplatin for metastatic triple-negative breast cancer. Presented at: 2025 ASCO Annual Meeting. May 30-June 3, 2025; Chicago, IL. Abstract e15144.