PD-1/PD-L1 inhibitors combined with chemotherapy or as monotherapy versus chemotherapy alone or observation in triple-negative breast cancer: a systematic review and updated meta-analysis incorporating long-term survival data.

Authors

Bing Guan, Yawen Chen, Rong Zhou, Sijia Zhang, Lulu Li, Ping He

Published in

Frontiers in immunology. Volume 17. Pages 1958007. Epub Oct 06, 2026.

Abstract

Multiple RCTs have established PD-1/PD-L1 inhibitors as standard in triple-negative breast cancer (TNBC), but prior meta-analyses lacked complete setting coverage, mature long-term survival data, and a quantification of chemotherapy-backbone impact-critical given IMpassion130 (nab-paclitaxel, positive) vs. IMpassion131 (paclitaxel, negative). This update includes final KEYNOTE-522 OS, GeparNuevo 7-year follow-up, and TORCHLIGHT Phase III data, covering neoadjuvant to metastatic disease.
We searched PubMed and ClinicalTrials.gov to May 2026 plus conference proceedings; an Embase search found no additional trials. Included RCTs compared ICI + chemotherapy vs. chemotherapy alone in TNBC, stratified by setting. The primary endpoints are OS (metastatic) and EFS/iDFS (early-stage). Pooled HRs used random-effects meta-analysis with HKSJ adjustment.
A total of 10 RCTs (5,953 patients) met the inclusion. In the metastatic setting (five RCTs, n = 3,526), ICI improved OS (HR 0.85, 95% CI 0.74-0.96; HKSJ-adjusted 0.70-1.03; I² = 27%) and PFS (HR 0.82, 0.73-0.92; I² = 35%); OS benefit was greater in PD-L1+ patients (HR 0.79, 0.65-0.95; I² = 51%). Numerically greater OS with anti-PD-1 vs. anti-PD-L1 was not robust in the sensitivity analysis. In the early-stage setting (five RCTs, n = 2,427), ICIs improved EFS/iDFS (HR 0.75, 0.63-0.90; I² = 0.2%) and OS (HR 0.64, 0.53-0.78; I² = 0%) and increased pCR (OR 1.65, 1.39-1.98; I² = 1%). HKSJ adjustment widened the Cis, but the effect patterns remained consistent.
This update confirms a consistent survival benefit of ICI + chemotherapy in both early and metastatic TNBC, which was most pronounced in PD-L1+ populations. Long-term data show durability, especially in neoadjuvant/adjuvant settings. The divergent outcomes with nab-paclitaxel vs. paclitaxel underscore the critical role of the chemotherapy backbone. These findings support current guidelines and highlight the need for refined biomarkers to extend benefit to PD-L1-negative patients.
https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD420261356428, identifier CRD420261356428.

PMID:
42903114
Bibliographic data and abstract were imported from PubMed on 22 Oct 2026.

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