Purpose Overall survival (OS) is the definitive and best-established primary efficacy end point to evaluate diffuse large B-cell lymphoma (DLBCL) therapies, but it requires prolonged follow-up. An earlier end point assessed post-treatment would expedite clinical trial conduct and accelerate patient access to effective new therapies. Our objective was to formally evaluate progression-free survival (PFS) and PFS at 24 months (PFS24) as surrogate end points for OS in first-line DLBCL. Patients and Methods Individual patient data were analyzed from 7,507 patients from 13 multicenter randomized controlled trials of active treatment in previously untreated DLBCL, published after 2002, with sufficient PFS data to predict treatment effects on OS. Trial-level surrogacy examining the correlation of treatment effect estimates of PFS/PFS24 and OS was evaluated using both linear regression ( R(2)WLS) and Copula bivariable ( R(2)Copula) models. Prespecified criteria for surrogacy required either R(2)WLS or R(2)Copula >/= 0.80 and neither < 0.7, with lower-bound 95% CI > 0.60. Results Trial-level surrogacy for PFS was strong ( R(2)WLS = 0.83; R(2)Copula = 0.85) and met the predefined criteria for surrogacy. At the patient level, PFS strongly correlated with OS. The surrogate threshold effect had a hazard ratio of 0.89. Surrogacy was consistent across comparisons with or without rituximab and with rituximab maintenance trials. Trial-level surrogacy for PFS24 was relatively strong ( R(2)WLS = 0.77; R(2)Copula = 0.78) but did not meet prespecified criteria. At the patient level, PFS24 significantly correlated with OS. The surrogate threshold effect had an odds ratio of 1.51. Conclusion This large pooled analysis of individual patient data supports PFS as a surrogate end point for OS in future randomized controlled trials evaluating chemoimmunotherapy in DLBCL. Use of this end point may expedite therapeutic development with the intent of bringing novel therapies to this patient population years before OS results are mature.
PubMed ID: 29975624
Projects: German Lymphoma Alliance (GLA)
Publication type: Not specified
Journal: J Clin Oncol
Human Diseases: Diffuse large b-cell lymphoma
Citation: J Clin Oncol. 2018 Sep 1;36(25):2593-2602. doi: 10.1200/JCO.2018.77.9124. Epub 2018 Jul 5.
Date Published: 1st Sep 2018
Registered Mode: by PubMed ID
Created: 17th Apr 2019 at 14:02
Last updated: 16th May 2019 at 15:12