A network meta-analysis assessing the comparative effectiveness of neoadjuvant therapy for HER2-positive breast cancer.

e11598 Background: The growing number of anti-HER2 agents suggests the eventual need for defining the optimal choice of neoadjuvant therapy for HER2-positive breast cancer. Multiple-treatments meta-analysis synthesizes information from a network of trials and combines direct and indirect evidence on the relative effectiveness. An indirect estimate of the benefit of A over B can be obtained by comparing trials of A v C with trials of B v C. In this study, we assessed the efficacy and safety of neoadjuvant therapy for HER2-positive breast cancer by conducting the direct and indirect comparisons from multiple RCTs. Methods: The primary outcome of the study was the number of the patients who achieved pathological complete response (pCR) defined as no invasive residual in breast or node. Secondary objectives were the number of patients who completed the treatment as planned and adverse events including diarrhea, neutropenia, cardiac events and skin disorder. Results: We identified 1047 articles by database search and 10 studies met our criteria. A total of 2247 patients in 7 different treatment arms were assessed; chemotherapy (CT) alone, CT with single or dual anti-HER2 agents and dual anti-HER2 agents without CT. Anti-HER2 agents evaluated were trastuzumab (T-mab), lapatinib, pertuzumab (P-mab). There was no significant difference between dual targeting treatment arms (CT + T-mab + lapatinib v CT + T-mab + P-mab, OR; 1.11, [0.42-2.86], p=0.41), however, lapatinib reduced the treatment completion mainly due to adverse events. Patients in dual targeting arms had significantly higher incidence of pCR than in other treatment arms. (CT + T-mab + P-mab v CT + T-mab, OR; 2.29, [1.02-5.02], p=0.02) Surface under the cumulative ranking probability curve (SUCRA) also indicated that CT + T-mab + P-mab had the highest probability of being the best treatment arm for pCR followed by CT + T-mab + lapatinib and CT + T-mab. Conclusions: This study provides evidence that combining two anti-HER2 agents with chemotherapy are the most effective treatment arms. Considering the cost and limited medical resources, CT + T-mab showed a well-balanced profile for efficacy, completion and safety.