Bortezomib‐based chemotherapy in Chinese pediatric patients with relapsed/refractory acute lymphoblastic leukemia: A single‐center retrospective study

ABSTRACT Importance Relapsed/refractory acute lymphoblastic leukemia (R/R ALL) remains a major challenge in pediatric hematologic malignancies, with poor outcomes following standard salvage therapy. Real‐world data regarding the use of bortezomib‐based regimens in Chinese children are limited. Objective To evaluate the effectiveness and safety of bortezomib‐based chemotherapy in Chinese pediatric patients with R/R ALL. Methods We retrospectively reviewed 12 pediatric patients with R/R ALL who received bortezomib‐based chemotherapy at our center between January 2019 and January 2026. Clinical characteristics, responses, survival, and adverse events were evaluated. Complete remission (CR), CR with incomplete recovery (CRi), persistent disease (PD), and minimal residual disease (MRD) were assessed per standard criteria. Survival probabilities were estimated using the Kaplan–Meier analysis. Results Nine patients had B‐cell ALL (B‐ALL) and three had T‐cell ALL (T‐ALL). Among those with B‐ALL, the CR/CRi rate was 88.9% (8/9), and 62.5% (5/8) of responders bridged to hematopoietic stem cell transplantation (HSCT). Notably, five of eight responders with B‐ALL achieved MRD <0.01%, including all three refractory patients. In contrast, none of the three patients with T‐ALL achieved remission; all experienced PD, with a median survival of 3 months. The 3‐year overall survival and event‐free survival rates for the entire cohort were 48.6% (95% confidence interval [CI], 19.2%–73.0%) and 36.4% (95% CI, 5.8%–69.8%), respectively. Treatment‐related toxicities were manageable, with the most common being hematologic suppression and infections. Interpretation Bortezomib‐based chemotherapy showed promising salvage activity in pediatric patients with R/R B‐ALL, enabling remission and HSCT bridging. However, its activity against T‐ALL appears limited in this small cohort, warranting further investigation.