Tisagenlecleucel vs. historical standard of care in children and young adult patients with relapsed/refractory B-cell precursor acute lymphoblastic leukemia

In the absence of randomized controlled trials comparing tisagenlecleucel vs. standard of care (SOC) in pediatric and young adult patients with relapsed or refractory acute lymphoblastic leukemia (r/r ALL), the objective was to compare the efficacy of tisagenlecleucel with historical controls from multiple disease registries using patient-level adjustment of the historical controls. The analysis is based on patient-level data of three tisagenlecleucel studies (ELIANA, ENSIGN and CCTL019B2001X) vs. three registries in Germany/Austria. Statistical analyses were fully pre-specified and propensity score weighting of the historical controls by fine stratification weights was used to adjust for relevant confounders identified by systematic literature review. Results showed high comparability of cohorts after adjustment with absolute SMD ≤ 0.1 for all pre-specified confounders and favorable outcomes for tisagenlecleucel compared to SOC for all examined endpoints. Hazard ratios for OS (Intention to treat)ITT,adjusted , EFS (Full analysis set)FAS,naïve and RFS FAS,naïve were 0.54 (95% CI: 0.41–0.71, p < 0.001), 0.67 (0.52–0.86, p = 0.001) and 0.77 (0.51–1.18, p = 0.233). The OS ITT, adjusted , EFS FAS,naïve and RFS FAS,naive survival probability at 2 years was 59.49% for tisagenlecleucel vs. 36.16% for SOC population, 42.31% vs. 30.23% and 59.60% vs. 54.57%, respectively. Odds ratio for ORR ITT,adjusted was 1.99 (1.33–2.97, p < 0.001). Results for OS and ORR were statistically significant after adjustment for confounders and provide evidence supporting a superiority of tisagenlecleucel in r/r ALL given the good comparability of cohorts after adjustment for confounders.