Openshaw, Thomas H.

Importance Observational studies of survivors of breast cancer and prospective trials of aspirin for cardiovascular disease suggest improved breast cancer survival among aspirin users, but prospective studies of aspirin to prevent breast cancer recurrence are lacking. Objective To determine whether aspirin decreases the risk of invasive cancer events among survivors of breast cancer. Design, Setting, and Participants A011502, a phase 3, randomized, placebo-controlled, double-blind trial conducted in the United States and Canada with 3020 participants who had high-risk nonmetastatic breast cancer, enrolled participants from 534 sites from January 6, 2017, through December 4, 2020, with follow-up to March 4, 2023. Interventions Participants were randomized (stratified for hormone receptor status [positive vs negative], body mass index [≤30 vs >30], stage II vs III, and time since diagnosis [<18 vs ≥18 months]) to receive 300 mg of aspirin (n = 1510) or placebo once daily (n = 1510) for 5 years. Main Outcomes and Measures The primary outcome was invasive disease–free survival. Overall survival was a key secondary outcome. Results A total of 3020 participants were randomized when the data and safety monitoring committee recommended suspending the study at the first interim analysis because the hazard ratio had crossed the prespecified futility bound. By median follow-up of 33.8 months (range, 0.1-72.6 months), 253 invasive disease–free survival events were observed (141 in the aspirin group and 112 in the placebo group), yielding a hazard ratio of 1.27 (95% CI, 0.99-1.63; P = .06). All invasive disease–free survival events, including death, invasive progression (both distant and locoregional), and new primary events, were numerically higher in the aspirin group, although the differences were not statistically significant. There was no difference in overall survival (hazard ratio, 1.19; 95% CI, 0.82-1.72). Rates of grades 3 and 4 adverse events were similar in both groups. Conclusion and Relevance Among participants with high-risk nonmetastatic breast cancer, daily aspirin therapy did not improve risk of breast cancer recurrence or survival in early follow-up. Despite its promise and wide availability, aspirin should not be recommended as an adjuvant breast cancer treatment. Trial Registration ClinicalTrials.gov Identifier: NCT02927249

1016 Background: The ph III EMBRACE trial of E vs physician’s choice of tx led to FDA approval of E as ≥3rd-line tx for MBC pts with prior exposure to anthracyclines/taxanes. The ph III BOLD 301 trial of E vs capecitabine in advanced BC treated with anthracyclines/taxanes showed a nonsignificant trend to improved median OS for all pts; pre-planned analysis by HER2 status revealed a nominally significant benefit for HER2- pts. Methods: RU011201I is an investigator initiated ph III trial with 1:1 randomization to E (1.4 mg/m2 D1,8 q21days) vs P (90 mg/m2 D1,8,15 q28days) within strata defined by (neo)adjuvant taxanes (yes/no), HR status (+/-), and line of tx (1st/2nd). Pts had measurable or non-measurable disease by RECIST v1.1; new or progressive mets; peripheral neuropathy (PN) gr<2; ≤1 prior chemotx regimens for advanced or MBC. Asymptomatic brain mets with stable MRIs for >3 mos were allowed. (Neo)adjuvant taxanes were allowed if >12 mos between tx completion and disease recurrence. Radiographic studies occur q12wks. Survival data are collected q12wks after the Off-Tx Visit. Pts reported side effects weekly; post-baseline symptomatic AE rates worse than baseline were compared between arms using Fisher’s exact tests. We report clinical outcomes and the primary objective related to PRO-CTCAE use. Results: 201 pts enrolled 3/2014 - 5/2018 with 33.8 mos median f/u; 3 are on tx as of 2/20/20 (1E, 2P). Pt characteristics were the same between E vs P: median age 62 yrs (range 27-85); 42% prior taxane; 78% ER+; 70% starting 1st line tx. Baseline lesion distribution was similar except for lung mets (37E, 53P). No difference was seen between E vs P in PFS (5.7 vs 5.9 mos; P=0.72), OS (18.1 vs 16.4 mos; P=0.75), TTF (5.3 vs 4.9 mos; P=0.82), DOR (10.8 vs 12.3 mos; P=0.84), or number of metastatic events (55 vs 54). 37E and 36P pts required ≥1 dose reduction. Hematologic toxicities ≥ gr 3 were higher with E (40 vs 22%). PN events were similar: 56 vs 58 total, 4 vs 7 motor, 52 vs 51 sensory. Median duration of PN and median time to 1st PN event were 74 vs 140 and 56 vs 41 days. Worsened numbness/tingling severity and other pt-reported AE rates were similar, but worsened numbness/tingling interference (63% vs 78%, P=0.04) and vomiting frequency (35% vs 57%, P=0.005) were lower with E. Conclusions: Clinical outcomes were equivalent with E vs P as 1st/2nd line tx for HER2- advanced BC. The nature and severity of PN were similar between arms, but time of onset, duration, and interference with daily living favor E. E may be a suitable treatment option in this setting. Clinical trial information: NCT02037529 .