525 Background: Triple-negative breast cancer (TNBC) is a highly heterogeneous disease with variable clinical outcomes. We have previously classified patients with TNBC into high- and low-risk groups based on a multigene signature. In this study, we aimed to evaluate the feasibility of utilizing a multigene signature to tailor individualized adjuvant therapy for patients with operable TNBC. Methods: This multicenter, open-label, randomized, phase 3 trial was conducted at 7 cancer centers in China. We included female patients aged 18-70 years with early TNBC after definitive surgery (histologically confirmed axillary lymph node-positive or lymph node-negative with tumor diameter >10 mm). After categorization using the integrated signature, high-risk patients were randomized (1:1) to receive an intensive adjuvant treatment comprising four cycles of docetaxel, epirubicin, and cyclophosphamide followed by four cycles of gemcitabine and cisplatin (TEC-GP; arm A), or the standard four cycles of epirubicin and cyclophosphamide followed by four cycles of docetaxel (EC-T; arm B). Low-risk patients received the same adjuvant chemotherapy as arm B (arm C). The primary endpoint was disease-free survival (DFS) in the intention-to-treat analysis of arm A versus arm B. Results: Between January 2016 and July 2023, 504 patients (336 high-risk and 168 low-risk; median age, 52 years; 488 with T1-2 tumors; 263 with node-positive disease) were recruited. At a median follow-up of 45.1 months, the 3-year DFS rates were 90.9% for patients in arm A and 80.6% for patients in arm B (hazard ratio [HR], 0.51; 95% confidence interval [CI], 0.28 to 0.95; P = 0.030). Intensive chemotherapy improved DFS relative to standard therapy irrespective of tumor size and nodal status. The 3-year RFS was 92.6% in arm A and 83.2% in arm B (HR, 0.50; 95% CI, 0.25 to 0.98; P = 0.039). The groups did not differ in OS (HR, 0.58; 95% CI, 0.22 to 1.54; P = 0.267; 3-year OS, 98.2% vs 91.3%). Upon receiving the same chemotherapy regimen, patients in arm C had significantly higher DFS (HR, 0.57; 95% CI, 0.33-0.98; P = 0.038; 3-year DFS, 90.1% vs 80.6%), RFS (HR, 0.42; 95% CI, 0.22-0.81; P = 0.007; 3-year RFS, 94.5% vs 83.2%) and OS (HR, 0.14; 95% CI, 0.03-0.61; P = 0.002; 3-year OS, 100% vs 91.3%) compared to patients in arm B. The incidence of grade 3 to 4 treatment-related adverse. events for arms A, B and C, respectively, were thrombocytopenia (14.1%, 2.5%, 1.8%), febrile neutropenia (9.9%, 4.3%, 4.9%), anemia (5.8%, 1.9%, 1.8%), nausea (7.0%, 3.7%, 4.9%), vomiting (8.3%, 4.3%, 4.9%) and myalgia (2.6%, 5.6%, 5.5%). There were no treatment-related deaths. Conclusions: The multigene signature showed potential for tailoring adjuvant chemotherapy for patients with operable TNBC. Intensive regimens incorporating GP into anthracycline/taxane-based therapy improves survival with manageable toxicity. Clinical trial information: NCT02641847 .