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To meet regulatory expectations for Donidalorsen’s BLA, Ionis Pharmaceuticals engaged Certara’s Pharmacometrics experts to develop a validated exposure–response model linking drug exposure, biomarker response, and clinical outcomes. The resulting analysis supported dose optimization and accelerated submission timelines.

The challenge

As Ionis prepared its Biologics License Application (BLA) for Donidalorsen—a novel RNA-targeted antisense oligonucleotide designed to treat hereditary angioedema (HAE)—the company faced the challenge of justifying an optimized and potentially less frequent dosing regimen. Specifically, they needed to quantitatively characterize the relationship between drug exposure, a biomarker (prekallikrein), and the primary efficacy endpoint: HAE attack rate. Regulatory expectations required robust modeling and simulation to support these dose optimization strategies, particularly as Ionis sought approval through an accelerated pathway.

Certara support

To support the BLA, Certara’s Pharmacometrics team used Phase 3 OASIS-HAE trial data to develop an exposure-response (E-R) model, applying Poisson regression to analyze HAE attack rate as count data. ​

Certara’s team:​

  • Established an E-R model describing HAE attack rate as a function of prekallikrein concentrations, incorporating a sigmoidal Emax relationship with baseline covariates.​
  • Validated the model externally using Phase II data to ensure predictive reliability.​
  • Conducted simulations to evaluate the clinical impact of switching well-responding patients from monthly (Q1M) to every-two-months (Q2M) dosing, showing sustained reduction in attack rate.​
  • Supported the BLA submission, integrating all modeling components, and assisting with regulatory presentations and documentation.​
  • Collaborated cross-functionally, delivering seamless integration across clinical pharmacology, pharmacometrics, and regulatory teams.​

The impact

With Certara’s support, Ionis:​

  • Demonstrated that less frequent dosing (Q2M) could maintain clinical efficacy in well-responding patients.​
  • Strengthened their BLA with a robust, validated exposure-response model that met regulatory expectations.​
  • Enabled flexible dosing options—offering potential improvements in patient convenience over existing therapies requiring frequent administration.​
  • Achieved accelerated submission timelines by efficiently handling complex modeling and documentation requirements.​
  • Minimized reporting delays and revisions, leveraging Certara’s medical writing expertise for streamlined submission readiness.​

FAQs

What is exposure–response (E–R) analysis?

Exposure–response analysis quantitatively characterizes the relationship between drug exposure (concentration in the body) and the resulting pharmacologic or clinical response. It helps determine how different doses affect efficacy, safety, and biomarkers, guiding optimal dosing strategies throughout drug development.

How is E–R analysis performed?

E–R modeling integrates pharmacokinetic, biomarker, and clinical data from trials to quantify dose–response or concentration–response relationships. Methods may include regression modeling, nonlinear mixed-effects models, or simulation-based approaches to explore different dosing scenarios and patient covariates.

What types of data are typically used in E–R models?

E–R models often leverage clinical data (such as efficacy endpoints and safety events), pharmacokinetic (PK) data, and relevant biomarkers. Together, these data types enable developers to evaluate the full exposure–response continuum.

What role does E–R analysis play in dose optimization?

E–R modeling can simulate outcomes under different dosing frequencies or patient characteristics, identifying regimens that maximize efficacy and minimize risk. For Donidalorsen, simulations supported the potential for every-two-month dosing in well-responding patients.

How was E–R analysis applied in the Ionis Donidalorsen program?

In the Donidalorsen development program for hereditary angioedema (HAE), E–R analysis was used to quantify the relationship between drug concentration, biomarker activity (prekallikrein), and attack rate. Modeling supported justification for a less frequent dosing regimen while maintaining efficacy.

Why is E–R analysis important in regulatory submissions?

Regulators such as the FDA and EMA expect E–R analyses to justify dose selection, support labeling, and strengthen benefit–risk assessments. A well-designed E–R model provides scientific evidence for the proposed dosing regimen and can reduce the need for additional clinical trials.

How is E–R analysis performed?

E–R modeling integrates pharmacokinetic, biomarker, and clinical data from trials to quantify dose–response or concentration–response relationships. Methods may include regression modeling, nonlinear mixed-effects models, or simulation-based approaches to explore different dosing scenarios and patient covariates.

How can E–R analysis streamline development?

By predicting responses across patient populations or dosing regimens, E–R modeling supports smarter trial design, reduces uncertainty, and can accelerate regulatory approval—especially when used to justify dose optimization or support accelerated or adaptive pathways.

What types of data are typically used in E–R models?

E–R models often leverage clinical data (such as efficacy endpoints and safety events), pharmacokinetic (PK) data, and relevant biomarkers. Together, these data types enable developers to evaluate the full exposure–response continuum.

How is model validation handled in E–R analysis?

Validation typically involves using external or cross-study data to confirm predictive performance. In the Donidalorsen program, the model was externally validated using Phase II data, demonstrating reliability and reproducibility for regulatory review.