A randomized, multicenter, open-label, phase III trial comparing anthracyclines followed by taxane versus anthracyclines followed by taxane plus carboplatin as (neo) adjuvant therapy in patients with early triple-negative breast cancer: Korean Cancer Study Group BR 15-1 PEARLY trial.

LBA502 Background: Triple-negative breast cancer (TNBC) is known for its high risk of early relapse and poor prognosis. Platinum agents have shown to increase pathological complete response (pCR) rates when added to neoadjuvant chemotherapy for TNBC. However, evidence regarding the survival benefit of platinum in this setting remains inconclusive. The PEARLY trial is a multicenter, randomized, open-label, phase 3 study designed to assess the efficacy and safety of carboplatin in combination with anthracycline/taxane therapy compared to standard anthracycline/taxane alone as either neoadjuvant or adjuvant treatment in early-stage TNBC. Methods: Patients with stage II or III TNBC were randomly assigned to either the carboplatin arm or the standard therapy arm, stratified by nodal status, institution, treatment setting (neoadjuvant vs adjuvant), and germline BRCA status. The standard therapy involved doxorubicin and cyclophosphamide (AC) followed by taxane treatment. The experimental arm included carboplatin in addition to taxane following AC. The primary endpoint was event-free survival (EFS), defined as disease progression or inoperable status for neoadjuvant therapy group, local or distant recurrence, occurrence of a second primary cancer, or death from any cause, while secondary endpoints encompassed overall survival (OS), invasive disease-free survival (IDFS), distant recurrence-free survival (DRFS), pCR rate, and safety. With a planned enrollment of 878 patients, the trial aimed for 80% power to detect a hazard ratio of 0.70 for EFS at a two-sided alpha level of 0.05, anticipating 248 EFS events over a 5-year follow-up period. Results: Between Jan 2016 and Jun 2020, 868 patients across 22 institutions in South Korea were enrolled. At a median follow-up of 51.1 months, carboplatin significantly improved EFS compared to the control arm (hazard ratio HR, 0.68; 95% confidence interval CI: 0.50 to 0.93; p=0.017). The 5-year EFS rates were increased from 74.4% to 81.9%, demonstrating a 7.5% difference. Subgroup analysis showed consistent benefits across various patient categories. Secondary endpoints like IDFS and DRFS also favored carboplatin arm. OS data were immature, a total of 43 patients (10.2%) in the carboplatin arm and 57 patients (13.1%) in the control arm died (HR 0.66; 95% CI: 0.42 to 1.01). Grade ≥3 treatment-related adverse event rates were 74.6% (1 death due to infection) in the carboplatin arm and 56.7% (2 deaths due to infection and suicide) in the control arm. Conclusions: The addition of carboplatin to standard anthracycline followed by taxane therapy significantly improved EFS in patients with early-stage TNBC. The safety profile was consistent with the known expectations for each regimen. Clinical trial information: NCT02441933 .