Qian Shi, PhD
Progression-free survival (PFS) appears to be a surrogate endpoint for overall survival (OS) in patients undergoing first-line treatment for diffuse large B-cell lymphoma (DLBCL), according to results from a large pooled analysis of 13 multicenter, randomized, controlled trials.1
Investigators with the Surrogate Endpoints for Aggressive Lymphoma (SEAL) group used linear regression (R2WLS
) and Copula bivariable (R2Copula
) models to assess the correlation of trial-level surrogacy with treatment effect estimates for PFS, PFS at 24 months (PFS24), and OS. To demonstrate surrogacy, either R2WLS
had to be ≥0.80 and and neither estimate could be <0.7. The prespecified lower-bound of the 95% CI was set at >0.6.
Trial-level surrogacy for PFS met the predefined criteria (R2WLS
= 0.83; 95% CI, 0.57-0.94 and R2Copula
= 0.85; 95% CI, 0.73-0.98), and investigators found that PFS strongly correlated with OS at the patient level. The rank correlation coefficient ρ between PFS and OS was 0.85 (95% CI, 0.84-0.86) for patient-level correlation.
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