On September 29, 2023, the FDA approved tocilizumab-bavi (Tofidence; Biogen), an interleukin-6 inhibitor and the first FDA-approved biosimilar to tocilizumab (Actemra), for the treatment of adults with moderate-to-severe rheumatoid arthritis who had an inadequate response to ≥1 disease-modifying antirheumatic drug (DMARD), patients aged ≥2 years with active polyarticular juvenile idiopathic arthritis (JIA), and patients aged ≥2 years with active systemic JIA.
The FDA approval was based on comprehensive analytical, nonclinical, and clinical data showing no clinically meaningful differences in efficacy, safety, or pharmacokinetics between tocilizumab-bavi and the reference drug tocilizumab. Data submitted to the FDA included the results of a double-blind, single-dose, 3-arm, parallel, phase 1 study (NCT03606876) that compared the pharmacokinetics, safety, and immunogenicity of tocilizumab-bavi with reference tocilizumab in healthy volunteers, and the results of a randomized, double-blind, multidose, 3-arm, parallel, phase 3 study (NCT03830203). This phase 3 study compared tocilizumab-bavi with reference tocilizumab to establish equivalent efficacy and comparable pharmacokinetic, safety, and immunogenicity profiles in patients with rheumatoid arthritis whose disease was inadequately controlled with methotrexate. The results showed that tocilizumab-bavi was highly similar to reference tocilizumab in efficacy, safety, and pharmacokinetics.
The most common (≥5%) adverse events with tocilizumab-bavi were upper respiratory tract infections, nasopharyngitis, headache, hypertension, and increased alanine aminotransferase. Injection-site reactions were also common with tocilizumab-bavi.
The prescribing information for tocilizumab-bavi includes a boxed warning stating that patients who receive tocilizumab-bavi have an increased risk for serious infections that can result in hospitalization or death. Most of the patients who had serious infections after treatment with tocilizumab-bavi were receiving concomitant immunosuppressant therapy, such as methotrexate or corticosteroids. The reported infections included active tuberculosis, invasive fungal infections (ie, candidiasis, aspergillosis, and pneumocystis), and bacterial, viral, and other infections that resulted from opportunistic pathogens.
When used as monotherapy or in combination with DMARDs, the recommended starting dose of tocilizumab-bavi is 4 mg/kg intravenously every 4 weeks followed by an increase to 8 mg/kg intravenously every 4 weeks based on clinical response.