In a Phase 1 clinical trial, researchers showed that CT-P10 is a biosimilar to Rituxan (rituximab), a current treatment of choice for rheumatoid arthritis (RA) patients who fail to respond to tumor necrosis factor (TNF)-targeting therapies, and its testing in further studies in patients is warranted. Both drugs showed equivalent efficacy and safety.
The study, “A multicentre randomised controlled trial to compare the pharmacokinetics, efficacy and safety of CT-P10 and innovator rituximab in patients with rheumatoid arthritis,” was published in the journal Annals of the Rheumatic Diseases.
Rituxan is a monoclonal antibody that targets a subset of immune cells called CD20+ B-cells. The treatment is approved for use in combination with methotrexate (MTX) in patients with RA who failed to respond to anti-TNF agents.
CT-P10 is a candidate bio-similar of Rituxan, with both drugs sharing primary structure, as well as highly similar higher-order structures, post-translational modifications, and in vitro biological activities.
An important point to understand is whether both drugs also share pharmacokinetic equivalence, i.e., whether both show similar drug absorption, distribution, metabolism, and excretion. To this end, researchers performed a Phase 1 trial, called “Demonstrate the Equivalence of CT-P10 to MabThera With Respect to the Pharmacokinetic Profile in Patients With Rheumatoid Arthritis (Triad RA)” (NCT01534884).
The study included patients with active RA who were randomly assigned to receive 1,000 mg CT-P10 or Rituxan at weeks 0 and 2 (all patients continued to receive MTX therapy). In total, 103 patients were treated with CT-P10 and 51 with Rituxan.
Results showed that the study’s primary endpoints concerning the pharmacokinetic profile — more specifically, the serum concentration-time curve and the maximum serum concentration after the second infusion — were found equivalent between CT-P10 and Rituxan.
Additionally, both drugs also showed a high similar efficacy — ACR/EULAR responses and DAS28 scores (disease activity scores) in the group treated with CT-P10 and that with Rituxan were similar to those observed with Rituxan in the REFLEX and DANCER trials.
The safety profile was also comparable between CT-P10 and Rituxan, with the incidence of infusion-related reactions declining with subsequent infusions in both groups.
Researchers concluded that CT-P10 and Rituxan exhibit an equivalent pharmacokinetic profile and comparable efficacy, safety, and biological activity up to week 24 in patients with RA, ultimately supporting future studies of CT-P10 in RA patients.