Constructing an External Control Arm Using the French REALYSA Cohort to Replicate Outcomes of a Randomized Trial Arm in Advanced Hodgkin Lymphoma
In brief
Real-world control arm matches trial progression-free survival in advanced Hodgkin lymphoma
Using the French REALYSA registry, researchers built an external control cohort that met the eligibility of the AHL2011 trial and applied propensity-score weighting. The resulting progression-free survival was virtually identical to the randomized arm (hazard ratio 0.98), and response rates were comparable. This suggests well-balanced real-world data can serve as a reliable comparator, though validation in other settings is still needed.
- Journal
- Clinical pharmacology and therapeutics (Q1)
- Published
- 7 September 2026
- Study design
- Randomized controlled trial
- Evidence level
- Level 1, High (CEBM 1b)
- Authors
- Olivia Febvey-Combes, Cédric Rossi, Behrouz Kassai, Tesla Murairi Mirimo, Loïc Chartier, Fanny Cherblanc, et al.
- PMID
- 42704204
- DOI
- 10.1002/cpt.70470
Why clinicians should know about it
- Picked for Hematology (top studies of the week, 13 September 2026): External control arm replicates Hodgkin lymphoma RCT outcomes
- Picked for Epidemiology (paper of the day, 9 September 2026): External control arm built from real‑world cohort data
Abstract
External control (EC) arms using routine data can be used as comparators in clinical trials under certain conditions. The objective of this study was to assess the ability of an EC arm to replicate outcomes of a randomized controlled trial (RCT) arm receiving the same treatment strategy in advanced stage classical Hodgkin lymphoma and serve as comparator in future trials. Using the prospective real-world data in lymphoma and survival in adults (REALYSA) cohort, we constructed an EC arm by applying eligibility criteria of the AHL2011 phase III RCT. Propensity score (PS) weighting was used to balance baseline characteristics between the EC arm and the RCT arm that received the same treatment. Progression-free survival (PFS) and overall response rate (ORR) at the end of first-line treatment were estimated in both arms. Hazard ratio (HR) for PFS and odds ratio (OR) for ORR were estimated using the EC arm as reference. A sensitivity analysis evaluated PS matching. Four hundred and ten RCT patients and 191 EC patients were analyzed. After PS weighting, patients' characteristics were well-balanced between arms. PFS estimates were similar in RCT and EC arms with an HR close to 1 (HR, 0.98; 95% CI, 0.59-1.62). ORR estimates were comparable in both arms. Weighting performed better than matching. Using PS weighting gave similar outcomes in the EC arm compared with the RCT arm. Our results suggest that EC studies using routine care data could be considered in the development of strategies for advanced Hodgkin lymphoma.
Abstract as published, via PubMed.
For healthcare professionals. The summary is generated by AI from the published abstract, and the evidence level is assigned automatically from the study design on the Oxford CEBM hierarchy. Neither is medical advice. Read the full paper before changing practice.