SB12 Eculizumab Biosimilar Candidate Demonstrates PK, PD Equivalence in Phase 1 Trial

A phase 1 study of the proposed eculizumab biosimilar (SB12) vs reference product (Soliris) has demonstrated pharmacokinetic (PK) bioequivalence and comparable pharmacodynamic (PD), safety, and immunogenicity characteristics in a population of healthy volunteers, investigators reported at the 2021 American Society of Hematology meeting.

Eculizumab is a humanized monoclonal antibody that binds to human C5 complement protein and blocks hemolysis, or the breakdown of red blood cells. Eculizumab is currently indicated for paroxysmal nocturnal hemoglobinuria, atypical hemolytic uremic syndrome, refractory generalized myasthenia gravis, and neuromyelitis optica spectrum disorder.

Investigators sought to demonstrate comparable PK and PD in healthy individuals aged 18 to 55 years (N = 240) who were randomized in a 3-arm trial to a single 300-mg dose of SB12 or US- and EU-sourced reference product. Blood samples for analysis were collected over 64 days.

The primary end point was PK similarity between the various agents as determined by total drug exposure, or area under the concentration-time curve. Biosimilarity for the primary end point was confirmed, as the 90% CIs were within the predetermined equivalence margin of 80% to 125%, authors of the study wrote.

Investigators said there were no deaths or discontinuation of investigational products (IPs) due to treatment-emergent adverse events (TEAEs); they said there were 2 serious adverse events: renal colic in the SB12 cohort and back pain in the US-eculizumab group. “Both events were considered not related to the IP,” investigators wrote.

They said 70.0%, 65.0%, and 71.3% of patients in the SB12 and EU- and US-sourced eculizumab cohorts, respectively, experienced TEAEs, which investigators said was similar.

The number of participants who developed postdose antidrug antibodies (ADA) to eculizumab was 2 (2.5%), 1 (1.3%), and 0 (0.0%), respectively, authors wrote. “There was no significant difference between treatment groups. None of the [participants] with post-dose ADA to eculizumab had a positive result for neutralizing antibodies.”

Reference

Lee HA, Jang H, Kim Y, et al. A randomized, double-blind, single-dose phase 1 comparative pharmacokinetic study comparing SB12 (eculizumab biosimilar) with reference eculizumab in healthy volunteers. Presented at: ASH 2021; December 11-14, 2021. Abstract 929.