Combined hormone therapy and targeted therapy should be the first choice for most postmenopausal women with recently diagnosed hormone receptor–positive, HER2-negative metastatic breast cancer, new data suggest.
Although guidelines support use of hormone therapies with or without targeted therapies in this population, up-front chemotherapy is still commonly used even in the absence of a visceral crisis, noted lead investigator, of the department of clinical medicine and surgery at the University of Naples (Italy) Federico II, and colleagues.
The investigators undertook a systematic review and network meta-analysis of 140 randomized, controlled trials among 50,029 postmenopausal patients with hormone receptor–positive, HER2-negative metastatic breast cancer treated in the first- and/or second-line setting.
Study results, reported in, showed that relative to standard hormone therapy alone, the combination of hormone therapy with a targeted therapy – a CDK4/6 inhibitor, an mammalian target of rapamycin inhibitor, or an indicated phosphoinositide 3-kinase inhibitor – had significantly better efficacy, reducing the risk of progression-free survival events by more than half. In addition, no chemotherapy regimen, with or without targeted therapy, significantly outperformed the combination of hormone therapy with a CDK4/6 inhibitor.
Meanwhile, the hormone therapy–targeted therapy combinations had manageable toxicity, with the severity of adverse effects intermediate between that of hormone therapy alone and that of chemotherapy with or without targeted therapies.
“This study is, to our knowledge, the first to compare the efficacy and activity of all currently available chemotherapy and hormone therapy regimens, in combination with or without targeted therapies,” Dr. Giuliano and coinvestigators wrote. “[O]ur results corroborate the treatment algorithms recommended by the official oncology guidelines, supporting the use of new combinations of hormone therapies plus targeted therapies in the first-line or second-line setting in patients with hormone receptor-positive, HER2-negative metastatic breast cancer without visceral crisis.”
For the study, the investigators identified relevant phase 2 and phase 3 randomized, controlled trials published between 2000 and 2017, with the addition of several recently reported trials such as BOLERO-6 (JAMA Oncol. 2018;4:1367-74). Of the 140 trials ultimately included, 114 were used in the analysis of progression-free survival and time to progression, and 135 were used in the analysis of overall response.
Study results showed that when anastrozole (Arimidex) alone was the comparator, progression-free survival was significantly better with palbociclib (Ibrance) plus letrozole (Femara) (hazard ratio for events, 0.42); ribociclib (Kisqali) plus letrozole (HR, 0.43); abemaciclib (Verzenio) plus anastrozole or letrozole (HR, 0.42); palbociclib plus fulvestrant (Faslodex) (HR, 0.37); ribociclib plus fulvestrant (HR, 0.48); abemaciclib plus fulvestrant (HR, 0.44); everolimus (Afinitor) plus exemestane (Aromasin) (HR, 0.42); and, in patients with a PIK3CA mutation, the PI3K inhibitor alpelisib (Piqray) plus fulvestrant (HR, 0.39).
Several chemotherapy-based regimens, including anthracycline- and taxane-containing regimens, were also superior to anastrozole alone (hazard ratios, 0.41-0.47).
When palbociclib plus letrozole was the comparator, no chemotherapy or hormone therapy regimen yielded significantly better progression-free survival.
For the outcome of overall response, paclitaxel (Taxol) plus bevacizumab (Avastin) was the only clinically relevant regimen that significantly improved the likelihood of response relative to palbociclib plus letrozole (odds ratio, 8.95).
Dr. Giuliano reported that he receives honoraria from Amgen, AstraZeneca, Celgene, Eisai, Eli Lilly, Novartis, Pfizer,and Roche. The study did not receive any funding.
SOURCE: Giuliano M et al. Lancet Oncol. 2019 Sep 4. .