Mitch Dowsett1, I E Smith1, Anthony Skene1, Antonio Llombart‐Cussac1, José Mayordomo1, Simone Detre1, Janine Salter1, Eric Beresford1, Patrick Magill1
1Royal Marsden Hospital, London, United Kingdom; Royal Bournemouth Hospital, Bournemouth, United Kingdom; Hospital Arnau de Vilanova, Lleida, Spain; Hospital Lozano Blesa, Zaragoza, Spain; Astrazeneca, Macclesfield, United Kingdom
Tóm tắt
515 Background: Gefitinib, an EGFR-tyrosine kinase inhibitor, reduces breast cancer cell growth and potentiates endocrine therapy in model systems. This double-blind multicentre study compared anastrozole 1 mg/day alone with anastrozole + gefitinib 250 mg/day as neoadjuvant therapy for breast cancer in a novel design aiming to assess additional benefit from gefitinib in individual patients. Methods: Postmenopausal women with stage I-IIIB breast cancer and ER and/or PgR+ tumours received anastrozole for 16 wks and were randomised (2:5:5 ratio) to: combination with gefitinib for 16 wks (AG); placebo for 2 wks then gefitinib for 14 wks (A:AG, to test for additional Ki67 suppression); placebo for 16 wks (A alone). Biopsies were taken at baseline, 2 and 16 wks. Primary comparison was change in Ki67 by 16 wks. Secondary comparison was objective tumour response rate (ORR) using UICC/WHO criteria at 16 wks. Results: 206 patients (pts) were randomised: (31 AG, 90 A:AG, 85 A alone); demography was well balanced between the groups. 109 pts were evaluable for Ki67: 59 AG + A:AG; 50 A alone. Change in Ki67 levels at 16 wks was not significantly different in those pts who received gefitinib + anastrozole versus anastrozole alone (p=0.257). The addition of gefitinib after 2 weeks of anastrozole did not further suppress Ki67 levels (p=0.164). 188 pts were evaluable for ORR (109 AG + A:AG; 79 A alone). The ORR was 48% in pts who received gefitinib + anastrozole and 61% in pts treated with anastrozole alone (p=0.067). Conclusions: Neither the biological nor the clinical activity of anastrozole was enhanced by the addition of gefitinib; although non-significant, both endpoints unexpectedly suggested a trend against the combination in this patient population. Molecular investigations of signal transduction pathways are underway to understand the significance of these findings. [Table: see text] [Table: see text]
