A phase 2 trial of the CDK4 inhibitor dalpiciclib in well-differentiated or dedifferentiated liposarcoma.

Abstract

Listen

Translate article

11547 Background: The oncogene cyclin-dependent kinase 4 (CDK4) is amplified in > 90% of well-differentiated liposarcomas (WDLS) and dedifferentiated liposarcomas (DDLS). Previous studies have already demonstrated the clinical benefit of CDK4 inhibitors in the treatment of WDLS and DDLS. Dalpiciclib is a more potent and novel CDK4 inhibitor. We designed a multi-center phase 2 study to evaluate the safety and efficacy of dalpiciclib in patients with advanced WDLS/DDLS. Methods: Eligible patients were adults aged 18 years and older, with a confirmed diagnosis of advanced WDLS/DDLS, measurable lesions according to RECIST 1.1, any (or no) priory therapy, and a history of progression by RECIST 1.1 in the 6 months prior to enrollment. All patients were required to have CDK4 amplification by fluorescence in situ hybridization and retinoblastoma (RB) protein expression by immunohistochemistry. All patients were treated with dalpiciclib 150 mg orally once per day for 21 consecutive days within a 28-day treatment cycle. The primary endpoint was progression free survival (PFS) at 12 weeks. Secondary end points included objective response rate and adverse events. Results: From August 2022 to October 2023, a total of 32 patients were enrolled, and 30 were evaluable for the primary end point. Median (range) age was 59 (40-76) years; 22 patients (69%) were male. At 12 weeks, PFS was 61.3% (95% CI, 44-78.5%). The median PFS was 17.4 weeks (95% CI, 10.65-24.15 weeks). Only one patient had a partial response to the treatment. Grade 3 to 4 events included neutropenia (37.5%), anemia (6.25%), thrombocytopenia (6.25%), and nausea (3.13%). Conclusions: Treatment with the CDK4 inhibitor dalpiciclib was associated with a favorable PFS rate in patients with advanced CDK4-amplified and RB-expressing WDLS/DDLS. Clinical trial information: ChiCTR2200062868.