3 augustus 2011: Bron: Cancer. 2011 Jun 29. doi: 10.1002/cncr.26299.

Vrouwen in leeftijd na de overgang met hormoongevoelige gevorderde borstkanker kunnen baat hebben bij zowel aromasin - exemestaan als arimidex - anastrazole. Er zit weinig verschil in efectiviteit tussen ddeze twee middelen. Echter als een van de twee middelen faalt kan overstappen van arimidex - anastrazole naar aromasin - exemestane nog een redelijke kans op verbetering geven. 7 van de 16 patienten die overstapten hadden daarvan profijt. Omgekeerd is die kans veel minder. Slechts 1 van de 12 die overstapten had profijt daarvan. Dit blijkt uit een gerandomiseerde fase II studie bij 103 vrouwen met hormoongevoelige borstkanker. Opvallend is dat de onderzoekers met dit resultaat een reeds geplande fase III studie met dezelfde doelen annuleren. De verschillen zijn blijkbaar niet groot genoeg om een langjarige en dure fase III studie te rechtvaardigen. Hier het abstract van de studie. Het volledige studierapprot is tegen betaling in te zien bij Wileys online library.

Exemestane no better than anastrozole in breast cancer, but switching from failing arimidex to aromasin obtains a benefit in 45% of the patients

Source: Wileys online library

Cancer. 2011 Jun 29. doi: 10.1002/cncr.26299. [Epub ahead of print]

Exemestane versus anastrozole as front-line endocrine therapy in postmenopausal patients with hormone receptor-positive, advanced breast cancer: Final results from the Spanish Breast Cancer Group 2001-03 phase 2 randomized trial.

Llombart-Cussac A, Ruiz A, Antón A, Barnadas A, Antolín S, Alés-Martínez JE, Alvarez I, Andrés R, García Saenz JA, Lao J, Carrasco E, Cámara C, Casas I, Martín M.

Source

Medical Oncology Service, Biomedical Research Institute, Arnau de Vilanova University Hospital, Lleida, Spain; Medical Oncology Service, Oncology Institute of Valencia, Valencia, Spain. allombart@arnau.scs.es.

Abstract

BACKGROUND:

Several aromatase inhibitor studies have reported variations in the inhibitory potency of these agents that could lead to differences in clinical outcomes. In the current study, the authors formally evaluated the activity of anastrozole and exemestane in postmenopausal women with hormone-responsive, advanced breast cancer.

METHODS:

Postmenopausal women who had measurable disease according to Response Evaluation Criteria in Solid Tumors and had not received previous endocrine therapy for advanced breast cancer were randomized to receive either oral exemestane 25 mg daily or oral anastrozole 1 mg daily until they had disease progression. The primary endpoint was the objective response rate (ORR), and secondary endpoints included the clinical benefit rate (CBR), time to progression (TTP), overall survival, and safety. Crossover to the other aromatase inhibitor was permitted at the time of disease progression; ORR, CBR, and TTP after second-line treatment also were explored.

RESULTS:

In total, 103 patients were enrolled. The median patient age was 71.6 years, 52.4% of patients had visceral disease, and 75.8% of patients had ≥2 disease sites. Half of the patients had received previous tamoxifen, and 60% had received previous chemotherapy. The efficacy observed in the exemestane and anastrozole groups was an ORR of 36.2% and 46%, respectively; a CBR of 59.6% and 68%, respectively, and a TTP of 6.1 months and 12.1 months, respectively. At progression, 28 patients crossed over to the other aromatase inhibitor, including 16 patients who switched to exemestane (CBR, 43.7%; TTP, 4.4 months) and 12 patients who switched to anastrozole (CBR, 8.3%; TTP, 2 months). Both drugs were generally well tolerated, and no study drug-related serious adverse events were reported.

CONCLUSIONS:

In this phase 2 randomized trial, no significant differences in clinical activity were observed in favor of exemestane to justify a superiority phase 3 trial design in the first-line setting. Cancer 2011;. © 2011 American Cancer Society.