Building a Robust Evidence Strategy in a Rare, Rapidly Progressive Disease
For rare diseases such as cerebral adrenoleukodystrophy (cALD), conventional randomized trial designs may not always be ethical or feasible. Without a placebo group, sponsors need a credible way to evaluate treatment effects against the expected natural course of the disease.
Minoryx Therapeutics faced this challenge during the development of Nezglyal® (leriglitazone) for boys with cALD. Its pivotal NEXUS study was an open-label, single-arm study involving 23 boys aged two to 12 years, making a robust natural-history comparison central to the evidence strategy.
MMS conducted an in-depth literature review, extracted patient-level data from relevant natural-history publications, and developed a pre-specified statistical analysis plan for an external control arm. Propensity score-based weighting was used to balance important prognostic factors and create a more comparable basis for assessing treatment effect.
MMS also supported Minoryx Therapeutics throughout the European Medicines Agency review, responding to statistical questions and directly supporting the CHMP oral explanation. The Committee for Medicinal Products for Human Use subsequently issued a positive opinion recommending marketing authorization under exceptional circumstances for Nezglyal in a defined population of boys with cALD.
Key Benefits
- How patient-level real-world data can provide an external control when a placebo arm is unethical or unfeasible
- How natural-history evidence can be refined to create a more relevant comparison population
- How propensity score-based weighting can help balance prognostic differences
- Why a pre-specified statistical analysis plan is important during regulatory review
- How integrated biostatistics and biometrics expertise can support evidence generation and regulatory responses
- How statistical experts can help communicate the robustness and clinical relevance of external-control analyses to regulators
