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ATAC Updates from San Antonio. Tamar Safra, MD, Tel Aviv Sourasky Medical Centre. ( A rimidex, T amoxifen, A lone or in C ombination). Trial in Postmenopausal Women with Early Breast Cancer. Updated Efficacy Results Based on a Median Follow-up of 47 Months.
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ATAC Updates from San Antonio Tamar Safra, MD, Tel Aviv Sourasky Medical Centre.
(Arimidex, Tamoxifen, Alone or in Combination) Trial in Postmenopausal Women with Early Breast Cancer Updated Efficacy Results Based on a Median Follow-up of 47 Months Buzdar A. et al. The ATAC Trialists' Group. 25th San Antonio BCS 2002.
N N N N N CH3 H3C CH3 CH3 • Arimidex = Anastrozole • Highly selective potent aromatase inhibitor • Non-steroidal • Survival advantage vs. megestrol acetate • Superior to tamoxifen in receptor-positive advanced breast cancer • Main ATAC analysis (San Antonio 2001) in early breast cancer showed superior efficacy and safety profile compared with tamoxifen • Over 680,000 patient-years experience
(Arimidex, Tamoxifen, Alone or in Combination) • 9,366 patients with invasive breast cancer • 34% patients node-positive • 84% patients receptor-positive • - 8% receptor-negative • - 8% receptor-unknown • Mean age 64 years Buzdar A. et al. The ATAC Trialists' Group. 25th San Antonio BCS 2002.
(Arimidex, Tamoxifen, Alone or in Combination) • 9,366 patients with invasive breast cancer • 21 countries 381 centers Buzdar A. et al. The ATAC Trialists' Group. 25th San Antonio BCS 2002.
(Arimidex, Tamoxifen, Alone or in Combination) • 9,366 patients with invasive breast cancer • 21 countries • Design Surgery radiotherapy chemotherapy Randomization 1:1:1 for 5 years Anastrozole 1mg od + Tamoxifen placebo Anastrozole placebo + Tamoxifen 20mg od Anastrozole 1mg od + Tamoxifen 20mg od STOPPED Regular follow-up Buzdar A. et al. The ATAC Trialists' Group. 25th San Antonio BCS 2002.
(Arimidex, Tamoxifen, Alone or in Combination) • 9,366 patients with invasive breast cancer • 21 countries • Design • Primary endpoints: • Disease-free survival • Safety / tolerability • Secondary endpoints: • Incidence of contralateral breast cancer • Time to distant recurrence • Survival Buzdar A. et al. The ATAC Trialists' Group. 25th San Antonio BCS 2002.
2,939 Main analysis 3,000 2,580 2,500 Updated analysis 2,270 2,137 2,000 No. of cases 1,500 1,000 704 471 306 361 500 179 0 1 - 2 2 - 3 3 - 4 4 - 5 5 + Years (Arimidex, Tamoxifen, Alone or in Combination) Duration of follow-up • Results: Median =36months Median =47months 0 Buzdar A. et al. The ATAC Trialists' Group. 25th San Antonio BCS 2002.
Overall patients – % of patient with first event 10.0 Tamoxifen 8.0 Arimidex 7.1 6.2 6.0 % of patients 4.0 3.5 3.5 3.2 2.7 2.0 1.1 0.6 0.2 0.2 0 (Arimidex, Tamoxifen, Alone or in Combination) • Results: Total = 15.1% Total = 13.2% Locoregionalrecurrence Distant recurrence Contarlateral(invasive) Contarlateral(DCIS) Non B.C.Death Buzdar A. et al. The ATAC Trialists' Group. 25th San Antonio BCS 2002.
Tamoxifen 20 Arimidex 15 Proportion with first event (%) 10 5 0 0 6 12 18 24 30 36 42 48 54 Time to event (months) (Arimidex, Tamoxifen, Alone or in Combination) Overall patients – probability of a first event* • Results: HR = 0.86 CI = 0.76-0.99 P = 0.03 Absolutedifference=1.5% Absolutedifference=2.4% 36 48 * First event analysis includes the earliest occurrence of local or distant recurrence, new primary breast cancer or death from any cause Buzdar A. et al. The ATAC Trialists' Group. 25th San Antonio BCS 2002.
Tamoxifen 20 Arimidex 15 Proportion with first event (%) 10 5 0 0 6 12 18 24 30 36 42 48 54 Time to event (months) (Arimidex, Tamoxifen, Alone or in Combination) Overall patients – probability of recurrence • Results: HR = 0.86 CI = 0.76-0.99 P = 0.03 HR = 0.83 CI = 0.71-0.96 P = 0.015 Absolutedifference= 1.7% Absolutedifference =2.3% 36 48 * Censoring non-BC deaths before recurrence Buzdar A. et al. The ATAC Trialists' Group. 25th San Antonio BCS 2002.
Receptor positive patients – % of patient with first event 10.0 Tamoxifen 8.0 Arimidex 6.1 6.0 % of patients 5.1 4.0 3.5 3.4 2.4 1.9 2.0 1.2 0.6 0.2 0.1 0 (Arimidex, Tamoxifen, Alone or in Combination) • Results: Total = 13.3% Total = 11.1% Locoregionalrecurrence Distant recurrence Contarlateral(invasive) Contarlateral(DCIS) Non B.C.Death Buzdar A. et al. The ATAC Trialists' Group. 25th San Antonio BCS 2002.
Tamoxifen 20 Arimidex 15 Proportion with first event (%) 10 5 0 0 6 12 18 24 30 36 42 48 54 Time to event (months) (Arimidex, Tamoxifen, Alone or in Combination) Receptor positive patients – probability of a first event • Results: HR = 0.82 CI = 0.70-0.96 P = 0.014 Absolutedifference =1.7% Absolutedifference =2.9% 36 48 Buzdar A. et al. The ATAC Trialists' Group. 25th San Antonio BCS 2002.
Tamoxifen 20 Arimidex 15 Proportion with first event (%) 10 5 0 0 6 12 18 24 30 36 42 48 54 Time to event (months) (Arimidex, Tamoxifen, Alone or in Combination) Receptor positive patients – probability of recurrence • Results: HR = 0.82 CI = 0.70-0.96 P = 0.014 HR = 0.78 CI = 0.65-0.93 P = 0.007 Absolutedifference =1.8% Absolutedifference =2.6% 36 48 Buzdar A. et al. The ATAC Trialists' Group. 25th San Antonio BCS 2002.
Years 0 1 2 3 4 5 100 90 Estimated % without recurrence 80 70 (Arimidex, Tamoxifen, Alone or in Combination) Receptor positive patients – ATAC vs. EBCTCG • Results: (indirect comparison) Arimidex (ATAC) 92.2% Tamoxifen (ATAC) 89.6% 84.6% Tamoxifen (EBCTCG) 70.5% Placebo (EBCTCG) Buzdar A. et al. The ATAC Trialists' Group. 25th San Antonio BCS 2002.
Arimidex better Tamoxifen better 0.25 0.60 0.80 1.00 1.25 1.50 2.00 Hazard ratio (Arimidex, Tamoxifen, Alone or in Combination) Time to recurrence H.R. by subgroups • Results: Receptor status + ve - ve Nodal status 0 1-3 4+ Previous chemo no yes Buzdar A. et al. The ATAC Trialists' Group. 25th San Antonio BCS 2002.
Arimidex better Tamoxifen better 0.25 0.60 0.80 1.00 1.25 1.50 2.00 Hazard ratio (Arimidex, Tamoxifen, Alone or in Combination) Time to recurrence H.R. by subgroups • Results: Radiotherapy + ve - ve Definitive sergury mastectomy conservation 2 Tumor size 2 - 5 > 5 All patients Buzdar A. et al. The ATAC Trialists' Group. 25th San Antonio BCS 2002.
40 30 No. of cases 20 10 0 (Arimidex, Tamoxifen, Alone or in Combination) Incidence of New (Contralateral) Breast Primaries • Results: Overall Receptor positive DCIS - 5 Invasive35 DCIS - 4 HR = 0.62 CI = 0.38-1.02 P = 0.062 Invasive 31 HR = 0.56 CI = 0.32-0.98 P = 0.042 DCIS - 5 Invasive20 DCIS - 3 Invasive17 Tamoxifen Arimidex Tamoxifen Arimidex Buzdar A. et al. The ATAC Trialists' Group. 25th San Antonio BCS 2002.
11.4 12.5 Tamoxifen Arimidex 10.0 8.2 7.5 % of patients 4.5 3.5 5.0 2.8 2.1 2.3 1.0 2.5 0.5 0.1 0 (Arimidex, Tamoxifen, Alone or in Combination) • Side-effects (median therapy duration 30 months): P = 0.02 P < 0.0006 P < 0.0006 P < 0.0001 P < 0.0001 Cerebro-vascularevents Thrombo-embolicevents Endometrialcancer Vaginalbleeding Vaginaldischarge The ATAC Trialists' Group. Lancet 2002;359:2131-2139.
50 Tamoxifen 40 39.7 Arimidex 34.3 27.8 30 % of patients 21.3 20 10 5.9 3.7 0 (Arimidex, Tamoxifen, Alone or in Combination) • Side-effects (median therapy duration 30 months): P < 0.0001 P < 0.0001 P < 0.0001 Hotflushes Musculoskeletaldisorders Fractures The ATAC Trialists' Group. Lancet 2002;359:2131-2139.
2.0 Tamoxifen 1.0 Arimidex 1.01 0.48 0.0 -1.0 -1.68 -2.0 -2.59 -3.0 (Arimidex, Tamoxifen, Alone or in Combination) • Bone Mineral density sub protocol (n = 354): Lumbar BMD Total hip BMD Eastell R. et al. The ATAC Trialists' Group. 25th Nice ESMO 2002.
(Arimidex, Tamoxifen, Alone or in Combination) • QOL sub protocol (n = 1,021): • Patients completed a breast cancer questionnaire (FACT-B) together with an endocrine subscale at baseline and at 3, 6 12 months and every 6 months thereafter. • Primary endpoint was Trial Outcome Index (TOI), a summary score of the breast cancer scale and physical and functional well being subscales of the questionnaire. • There were no significant differences in TOI for Arimidex vs Tamoxifen (p = 0.23). • This sub-protocol indicates that there is no detrimental impact on QOL. Fallowfield C. et al. The ATAC Trialists' Group. 25th Nice ESMO 2002.
Arimidex better Tamoxifen better 0.30 0.40 0.60 0.80 1.00 1.25 1.50 2.00 Hazard ratio (Arimidex, Tamoxifen, Alone or in Combination) • Summary: DFS Overall R.R.R. = 14% Receptor +ve R.R.R. = 18% TTR Overall R.R.R. = 17% Receptor +ve R.R.R. = 22% Overall R.R.R. = 38% Contralateralbreast cancer Receptor +ve R.R.R. = 44% R.R.R. = Relative Risk Reduction Buzdar A. et al. The ATAC Trialists' Group. 25th San Antonio BCS 2002.
(Arimidex, Tamoxifen, Alone or in Combination) • Conclusion: • Efficacy advantages maintained. • Absolute differences increasing over time. • Favorable toxicity profile. • These data strongly support the use of Anastrozole (Arimidex) in the treatment of postmenopausal women with hormone-sensitive early breast cancer.