Long-term outcomes of neoadjuvant immunotherapy plus chemotherapy in patients with early-stage triple-negative breast cancer: an extracted individual patient data and trial-level meta-analysis

Background: Neoadjuvant immunotherapy (nIO) has emerged as a treatment option for stage II-III triple-negative breast cancer (TNBC). While randomised clinical trials (RCTs) demonstrated pathological complete response rate benefit to nIO added to chemotherapy, additional data on long-term outcomes is warranted. We performed this analysis to evaluate long-term efficacy outcomes of nIO in TNBC.

Methods: We searched databases for RCTs evaluating nIO in early-stage TNBC. A meta-analysis of extracted individual patient data (EIPD) was performed to evaluate EFS and OS, with data from reported Kaplan-Meier plots. Additionally, we conducted a trial-level meta-analysis using fixed and random effects models.

Results: The literature search resulted in four included RCTs with available EFS or OS (KEYNOTE-522, IMpassion031, I-SPY2 and GeparNuevo). EIPD showed that the addition of nIO to chemotherapy provides statistically significant benefits in EFS (HR 0.62, 0.50-0.76; p < 0.001) and OS (HR 0.62, 0.46-0.82, p < 0.001). Number needed to treat to avoid one EFS or OS event in 4 years was 9 and 14, respectively. Trial-level meta-analysis yielded similar results (EFS: HR 0.64, 0.51-0.79; OS: 0.57, 0.37-0.89).

Conclusions: Results show that nIO combined with chemotherapy can provide significant EFS and OS benefits, supporting its use as standard treatment for early-stage TNBC.