Post Hoc Analysis of Recombinant C1 Inhibitor Clinical Data Using Contemporary Endpoints for Hereditary Angioedema

Area of Science:

• Immunology
• Pharmacology
• Clinical Trials

Background:

• Hereditary angioedema (HAE) attack severity is assessed using Patient Global Impression scales in contemporary trials.
• Legacy studies of recombinant human C1 esterase inhibitor (rhC1-INH) used different efficacy endpoints (VAS, TEQ).
• This analysis bridges historical and current HAE clinical trial endpoint methodologies.

Purpose of the Study:

• To evaluate pooled data from rhC1-INH trials for acute HAE attacks.
• To map legacy efficacy endpoints (VAS, TEQ) to contemporary scales (PGI-S, PGI-C).
• To assess the efficacy of rhC1-INH in terms of time to symptom relief and complete resolution.

Main Methods:

• Pooled data from three rhC1-INH trials (NCT00225147, NCT01188564, NCT00262301).
• Converted VAS and TEQ measurements to PGI-S and PGI-C using bookmarking study results.
• Calculated Kaplan-Meier estimates for time to symptom onset of relief (TOSR) and time to complete resolution (TTCR).

Main Results:

• Median TOSR was 0.75 hours with rhC1-INH vs. 8.00 hours with placebo (P < 0.001).
• Median TTCR was 4.50 hours with rhC1-INH vs. 24.00 hours with placebo (P < 0.001).
• rhC1-INH demonstrated statistically significant improvements in both TOSR and TTCR.

Conclusions:

• rhC1-INH significantly shortens TOSR and TTCR for HAE attacks compared to placebo.
• This post hoc analysis validates rhC1-INH efficacy using contemporary HAE trial endpoints.
• The findings support rhC1-INH as an effective treatment for acute HAE attacks.