329P Ribociclib (RIB) in patients (pts) with HR+/HER2− advanced breast cancer (ABC) and resistance to prior endocrine therapy (ET) in the MONALEESA (ML) -3 and -7 trials

Endocrine Therapy-Based Strategies for Metastatic Breast Cancer with Different Endocrine Sensitivity Statuses: A Systematic Review and Network Meta-Analysis

BACKGROUND

Novel endocrine therapies (ETs) and targeted therapeutic regimens have been developed to dramatically improve the outcome of hormone receptor-positive (HR+)/HER2-negative (HER2-) metastatic breast cancer (mBC).

METHODS

We performed a systematic search with a predefined search strategy in PubMed, Embase and Cochrane CENTRAL databases to perform a network meta-analysis and evaluate the relative efficacies of ET-based treatment regimens in HR+/HER2- mBC patients with different endocrine sensitivity statuses. The study was registered in the PROSPERO database (CRD42021235570).

RESULTS

A total of 47 trials (20,267 patients) were included. Analysis of progression-free survival (PFS) in endocrine therapy-sensitive (ETS) patients revealed cyclin-dependent kinases 4/6 inhibitors (CDK4/6i) + fulvestrant 500 mg (Ful 500) (random effect (RE): hazard ratio (HR), 0.46; 95% credibility interval (CrI), 0.27-0.78; surface under the cumulative ranking curve (SUCRA), 0.93; fixed effect (FE): HR, 0.48; 95% CrI, 0.40-0.58; SUCRA, 0.99) to be the best therapy followed by CDK4/6i + aromatase inhibitors (AIs) (RE: HR, 0.53; 95% CrI, 0.40-0.72; SUCRA, 0.86; FE: HR, 0.54; 95% CrI, 0.48-0.61; SUCRA, 0.91). Chemotherapy followed by CDK4/6i + Ful 500 appears to be the most effective option for the endocrine therapy-resistant (ETR) group. Analysis of overall survival revealed CDK4/6i + Ful 500 (SUCRA: 0.99) and AKTi + Ful 500 (SUCRA: 0.87) to be the first-rank regimen for the ETS group and ETR groups, respectively.

CONCLUSION

Our comprehensive analysis suggests that CDK4/6i combined with ETs may be the best treatment option in terms of PFS for ETS patients and chemotherapy for ETR patients with HR+/HER2- mBC. Different endocrine sensitivity statuses required various optimal treatment strategies, which may provide guidance for clinical practice.

Ribociclib efficacy in special populations and analysis of patient reported outcomes in the MONALEESA trials

INTRODUCTION

Cyclin-dependent kinase 4/6 (CDK4/6) inhibitors abemaciclib, palbociclib and ribociclib radically modified the treatment of hormone receptor-positive/human epidermal growth factor 2-negative advanced breast cancer. Ribociclib efficacy was proved in the phase III MONALEESA-2, -3 and -7 trials. In the first-line setting, ribociclib plus endocrine therapy determined statistically significant improvements in progression-free (PFS) and overall survival (OS) in pre-menopausal (MONALEESA-7) and post-menopausal (MONALEESA-2) women. Likewise, ribociclib and fulvestrant induced a significant PFS and OS benefit in post-menopausal women previously treated with endocrine therapy (MONALEESA-3). Additionally, ribociclib did not affect patient health-related quality of life in all the MONALEESA trials.

AREAS COVERED

We reviewed the results of the available randomized phase III trials testing ribociclib and endocrine therapy in advanced breast cancer, focusing on different patient subgroups and then on health-related quality of life.

EXPERT OPINION

The benefit of ribociclib was consistent across patient subgroups and is maintained in populations with unfavorable features, such as those with endocrine resistance or visceral metastases. Furthermore, the addition of ribociclib to endocrine therapy delays quality of life deterioration and improves pain scores. These results represent a pivotal improvement for the treatment of advanced breast cancer patients receiving CDK4/6 inhibitors.