Biosimilar Candidate PF-06410293 Shows Similarity to Humira at 26 Weeks

Pfizer’s PF-06410293, a proposed biosimilar adalimumab referencing Humira, shares similar efficacy, safety, and immunogenicity profiles with its reference at 26 weeks of treatment, new research reports.

The 26-week study results, published in Arthritis Research and Therapy, are part of a 78-week, double-blind, multicenter, randomized study comparing the proposed biosimilar with EU-licensed Humira in 597 biologic-naïve patients with active rheumatoid arthritis that has not responded adequately to methotrexate. Patients were randomized to receive 40 mg of either PF-06410293 (n = 297) or the reference product (n = 300) every other week for 26 weeks in the first treatment period.

Click to read more about the adalimumab biosimilar pipeline.

The study’s primary end point was the proportion of patients reaching the American College of Rheumatology’s criteria for 20% improvement (ACR20) at week 12, which the investigators say is a sensitive timepoint for assessment of the speed of response as it represents the start of the plateau of the time-response curve for ACR20.

The 26-week period of initial treatment was completed by 286 patients in the biosimilar arm and 273 patients in the reference arm. In the biosimilar arm, 68.7% of patients achieved ACR20, as did 72.7% of patients in the reference arm; the treatment difference was −3.98%, which was contained within the prespecified equivalence margin of ±14%.

ACR20, 50, and 70 rates were similar through week 26 for both groups, as were mean changes from baseline in disease activity score in a count of 28 joints with C-reactive protein, as well as European League Against Rheumatism response rates and decrease from baseline in Health Assessment Questionnaire Disability Index scores.

A total of 143 patients (48.1%) in the biosimilar arm and 143 patients (47.8%) in the reference arm reported at least 1 treatment-emergent adverse event (TEAE), with infections and infestations being the most commonly reported for both arms. Serious AEs were reported by 4.0% and 4.3% of patients in the respective arms, including 1 death due to myocardial infarction in the reference arm.

Hypersensitivity-related TEAEs were reported in 4.4% of the biosimilar arm versus 8.4% of the reference arm, with the most frequently reported hypersensitivity reactions comprising cough, erythema, and rash.

In total, 44.4% of patients in the biosimilar arm and 50.5% of patients in the reference arm had at least 1 postdose blood sample that tested positive for antidrug antibodies (ADAs). The mean serum drug trough concentrations at week 26 were 8244 and 7190 ng/mL in the biosimilar and reference arms, respectively, and mean serum concentrations were lower in both arms in patients who had ADAs.

The authors of the study concluded that these 26-week results suggest that there is no clinically meaningful difference in safety, efficacy, immunogenicity, pharmacokinetics, or pharmacodynamics between the proposed biosimilar and its reference. Further results from the study—which involve rerandomization of patients in the reference arm at week 26 to either continue receiving the reference or switch to the proposed biosimilar, as well as a switch of all remaining patients in the reference-only arm to the biosimilar at week 52—are forthcoming.

Reference

Fleischmann RM, Alten R, Pileckyte M, et al. A comparative clinical study of PF-06410293, a candidate adalimumab biosimilar, and adalimumab reference product (Humira) in the treatment of active rheumatoid arthritis. Arthritis Res Ther. 2018;20(1):178. doi: 10.1186/s13075-018-1676-y.