Long-Term Outcomes of Adjuvant Denosumab in Breast Cancer

Outcomes of Adjuvant Denosumab in Breast CancerIn this long-term report of a prospective, double-blind, placebo-controlled, phase 3 trial of adjuvant aromatase inhibitor in postmenopausal patients with early hormone receptor-positive breast cancer, adjuvant denosumab therapy improved disease-free survival by 3.5 percentage points, bone metastasis-free survival by 2.5 percentage points, and overall survival by 1.0 percentage point at 9 years of follow-up.

Long-term outcomes of adjuvant denosumab in breast cancer: Fracture reduction and survival results from 3,425 patients in the randomised, double-blind, placebo-controlled ABCSG-18 trial

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Background: State-of-the-art adjuvant endocrine therapy with aromatase inhibitors (AI) compromises bone health in postmenopausal patients with hormone receptor-positive (HR+) breast cancer, increasing fracture incidence. Adjuvant treatment with the anti-RANK ligand denosumab (Dmab) counteracts these side effects and may improve outcomes. We here report the final long-term outcomes of the ABCSG-18 trial (ClinicalTrials.gov NCT00556374). Methods: In this prospective, double-blind, placebo-controlled, phase 3 trial, 3,425 postmenopausal patients with early HR+ breast cancer on AI therapy were randomised in 58 trial centers between 2006 and 2013 to receive either Dmab 60 mg or placebo s.c. every 6 months (q6m). The primary endpoint was time to first clinical fracture, secondary disease outcome-related endpoints were disease-free survival (DFS), bone-metastasis free survival (BMFS), and overall survival (OS). In addition to the main endpoint analyses reported previously, exploratory long-term follow-up was conducted in ABCSG-18. Main time-to-event analyses were based on stratified Cox models. Sensitivity analyses accounting for treatment cross-over associated with a late Dmab open-label phase, as well as for receiving any anti-resorptive agents were performed. Results: For this final protocol-defined analysis, median follow-up is 8 years (Q1,3: 6, 9.6), and all patients had ended their randomly assigned double-blind treatment (Dmab 60mg s.c. q6m n = 1711; placebo s.c. q6m n = 1709) for a median of 5 years. DFS was improved in the Dmab group versus the placebo group (309 versus 368 DFS events, hazard ratio (HR) 0.83, 95% CI 0.71-0.97, p = 0.016), resulting in an absolute 9-year DFS difference of 3.5% (79.4% vs 75.9%, respectively). When censoring for late cross-over and use of anti-resorptive agents, the DFS difference was confirmed (HR 0.82, p = 0.010). BMFS was improved by 19 per cent (HR 0.81, 95% CI 0.65-1.00, p = 0.047) in the Dmab group, and OS was improved by 20 per cent in the uncensored analysis (127 versus 158 OS events, HR 0.80, 95% CI 0.64-1.01, p = 0.065), and 26 per cent after censoring (HR 0.74, 95% CI 0.58-0.94, p = 0.013). The previously reported marked reduction in clinical fractures persisted even long-term, with 201 fractures in the Dmab and 255 fractures in the placebo group (HR 0.76, 95% CI 0.63-0.92, p = 0.004). No new toxicities for this (low) bone-protective dose of adjuvant Dmab were reported, particularly no ONJ occured.. Conclusions: Adjuvant Dmab 60mg every 6 months during AI therapy is safe, and markedly reduces treatment-induced clinical fractures even in the long-term. DFS, BMFS, and OS are improved in this descriptive final long-term analysis of ABCSG-18. Adjuvant denosumab should be considered for routine clinical use in postmenopausal patients with HR+ breast cancer. Clinical trial information: NCT00556374.

Duration of Adjuvant Aromatase-Inhibitor Therapy in Postmenopausal Breast Cancer

BACKGROUND

For postmenopausal women with hormone-receptor-positive breast cancer, the most effective duration for adjuvant therapy with an aromatase inhibitor remains unclear.

METHODS

In this prospective, phase 3 trial, we randomly assigned postmenopausal women with hormone-receptor-positive breast cancer who had received 5 years of adjuvant endocrine therapy to receive the aromatase inhibitor anastrozole for an additional 2 years (2-year group, receiving a total of 7 years) or an additional 5 years (5-year group, receiving a total of 10 years). The primary end point was disease-free survival. The primary analysis included all the patients who were still participating in the trial and who had no recurrence 2 years after randomization (i.e., when treatment in the 2-year group had ended). Secondary end points were overall survival, contralateral breast cancer, second primary cancer, and clinical bone fracture.

RESULTS

Among the 3484 women who were enrolled in the trial, 3208 remained in the trial without disease progression after the first 2 years of extended anastrozole treatment following randomization. Among these women, disease progression or death occurred in 335 women in each treatment group in the primary-analysis set at 8 years (hazard ratio, 0.99; 95% confidence interval [CI], 0.85 to 1.15; P = 0.90). No between-group differences occurred in most secondary end points, and subgroup analyses did not indicate differences in any particular subgroup. The risk of clinical bone fracture was higher in the 5-year group than in the 2-year group (hazard ratio, 1.35; 95% CI, 1.00 to 1.84).

CONCLUSIONS

In postmenopausal women with hormone-receptor-positive breast cancer who had received 5 years of adjuvant endocrine therapy, extending hormone therapy by 5 years provided no benefit over a 2-year extension but was associated with a greater risk of bone fracture. (Funded by AstraZeneca and the Austrian Breast and Colorectal Cancer Study Group; ABCSG-16/SALSA ClinicalTrials.gov number, NCT00295620.).

Endocrine therapy with or without whole breast irradiation in low-risk breast cancer patients after breast-conserving surgery: 10-year results of the Austrian Breast and Colorectal Cancer Study Group 8A trial

PURPOSE

To investigate long-term results of patients with hormonal receptor-positive breast cancer treated with breast-conserving surgery (BCS) and consecutive endocrine therapy (ET) with or without whole breast irradiation (WBI).

METHODS AND MATERIALS

Within the 8 A trial of the Austrian Breast and Colorectal Cancer Study Group, a total of 869 patients received ET after BCS which was randomly followed by WBI (n = 439, group 1) or observation (n = 430, group 2). WBI was applied up to a mean total dosage of 50 Gy (+/- 10 Gy boost) in conventional fractionation.

RESULTS

After a median follow-up of 9.89 years, 10 in-breast recurrences (IBRs) were observed in group 1 and 31 in group 2, resulting in a 10-year local recurrence-free survival (LRFS) of 97.5% and 92.4%, respectively (p = 0.004). This translated into significantly higher rates for disease-free survival (DFS): 94.5% group 1 vs 88.4% group 2, p = 0.0156. For distant metastases-free survival (DMFS) and overall survival (OS), respective 10-year rates amounted 96.7% and 86.6% for group 1 versus 96.4% and 87.6%, for group 2 (ns). WBI (hazard ratio [HR]: 0.27, p < 0.01) and tumour grading (HR: 3.76, p = 0.03) were found as significant predictors for IBR in multiple cox regression analysis.

CONCLUSIONS

After a median follow-up of 10 years, WBI resulted in a better local control and DFS compared with ET alone. The omission of WBI and tumour grading, respectively, were the only negative predictors for LRFS.

Adjuvant denosumab in postmenopausal patients with hormone receptor-positive breast cancer (ABCSG-18): disease-free survival results from a randomised, double-blind, placebo-controlled, phase 3 trial

BACKGROUND

In postmenopausal women with hormone receptor-positive, early-stage breast cancer, treatment with adjuvant aromatase inhibitors is the standard of care, but it increases risk for osteoporosis and fractures. Results from the ABCSG-18 trial showed that use of denosumab as an adjuvant to aromatase inhibitor therapy significantly reduced clinical fractures. Disease-free survival outcomes from ABCSG-18 have not yet been reported.

METHODS

Postmenopausal patients with early, hormone receptor-positive, non-metastatic adenocarcinoma of the breast, who had completed their initial adjuvant treatment pathway (surgery, radiotherapy, or chemotherapy, or a combination) and were receiving adjuvant aromatase inhibitors, were enrolled at 58 trial centres in Austria and Sweden into this prospective, double-blind, placebo-controlled, phase 3 trial. With permuted block randomisation (block sizes 2 and 4, stratified by previous aromatase inhibitor use, total lumbar spine bone mineral density score at baseline, and type of centre), patients were assigned (1:1) to receive subcutaneous denosumab (60 mg) or matching placebo every 6 months during aromatase inhibitor therapy. The primary endpoint (previously reported) was the time to first clinical fracture after randomisation. The secondary endpoint reported here is disease-free survival (defined as time from randomisation to first evidence of local or distant metastasis, contralateral breast cancer, secondary carcinoma, or death from any cause) in the intention-to-treat population. This study is registered with EudraCT (number 2005-005275-15) and ClinicalTrials.gov (number NCT00556374), and is ongoing for long-term follow-up.

FINDINGS

Between Dec 18, 2006, and July 22, 2013, 3425 eligible patients were enrolled and randomly assigned; 1711 to the denosumab group and 1709 to the placebo group (with five others withdrawing consent). After a median follow-up of 73 months (IQR 58-95), 240 (14·0%) patients in the denosumab and 287 (16·8%) in the placebo group had disease-free survival events. Disease-free survival was significantly improved in the denosumab group versus the placebo group (hazard ratio 0·82, 95% CI 0·69-0·98, Cox p=0·0260; descriptive analysis, without controlling for multiplicity). In the denosumab group, disease-free survival was 89·2% (95% CI 87·6-90·8) at 5 years and 80·6% (78·1-83·1) at 8 years of follow-up, compared with 87·3% (85·7-89·0) at 5 years and 77·5% (74·8-80·2) and 8 years in the placebo group. No independently adjudicated cases of osteonecrosis of the jaw or confirmed atypical femoral fractures were recorded. The total number of adverse events was similar in the denosumab group (1367 [including 521 serious] adverse events) and the placebo group (1339 [515 serious]). The most common serious adverse events were osteoarthritis (62 [3·6%] of 1709 in the denosumab group vs 58 [3·4%] of 1690 in the placebo group), meniscus injury (23 [1·3%] vs 24 [1·4%]), and cataract (16 [0·9%] vs 28 [1·7%]). One (<0·1%) treatment-related death (due to pneumonia, septic kidney failure, and cardiac decompensation) occurred in the denosumab group.

INTERPRETATION

Denosumab constitutes an effective and safe adjuvant treatment for patients with postmenopausal hormone receptor-positive early breast cancer receiving aromatase inhibitor therapy.

FUNDING

Amgen.

Randomized comparison of neoadjuvant docetaxel (D), epirubicin (E) and pegfilgrastim (P) (+ trastuzumab [T] in HER2+ patients [pts]) with and without capecitabine (C) for operable breast cancer (BC): Results of a planned safety analysis of ABCSG 24

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Background: ABCSG-24 is assessing the effect of adding C to DE and adding T to DE or DEC on pCR rate. Methods: Pts with operable BC (any T stage except T4d, N±, M0) scheduled for pre-operative chemotherapy were randomized to six 3- weekly cycles of D 75 mg/m2, d1 + E 75 mg/m2 d1 + P 6 mg d2, ± C 1,000 mg/m2 bid d1–14. Primary endpoint was pCR rate. After protocol amendment, HER2+ pts were also randomized to adjuvant ± neoadjuvant T. Results: From Nov 04 to Nov 06, 262 pts were enrolled, including 29 HER2+ pts. 145 are evaluable (DE: 74 pts, 400 cycles; DEC: 74 pts, 344 cycles). The table shows grade 3/4 adverse events (AEs) in >2% of pts in either arm. Febrile neutropenia was absent. Serious AEs occurred in 22% vs 20% of pts in DE vs DEC, respectively. Fewer pts in the DE than the DEC arm required dose reduction (0.5% vs 6.6% of cycles), withdrew consent (4% vs 13%) or were withdrawn by the investigator (1% vs 17%). Reasons for withdrawal by investigator were: HFS, stomatitis, mucositis, diarrhea, vomiting, peripheral neuropathy, fatigue, asthenia, docetaxel hypersensitivity, and asymptomatic liver enzyme elevation. No serious or grade 3/4 cardiac toxicity has occurred with T. Conclusions: Despite infrequent grade 3/4 AEs in both arms, more pts discontinued DEC than DE, by either patient’s or investigator’s choice. Since May 06, no DEC pts have withdrawn consent, perhaps because of improved pt education and symptom management. This finding reinforces the need for close monitoring and prompt management of AEs. The addition of C to DE presents no safety concerns. Efficacy results are due in 2008.

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