Consistent with the potentially immunogenic properties of protein and peptide pharmaceuticals, patients treated with VICTOZA may develop anti-liraglutide antibodies. The detection of antibody formation is highly dependent on the sensitivity and specificity of the assay. Additionally, the observed incidence of antibody (including neutralizing antibody) positivity in an assay may be influenced by several factors including assay methodology, sample handling, timing of sample collection, concomitant medications, and underlying disease. For these reasons, the incidence of antibodies to liraglutide cannot be directly compared with the incidence of antibodies of other products.

Approximately 50-70% of VICTOZA-treated patients in five double-blind clinical trials of 26 weeks duration or longer were tested for the presence of anti-liraglutide antibodies at the end of treatment. Low titers (concentrations not requiring dilution of serum) of anti-liraglutide antibodies were detected in 8.6% of these VICTOZA-treated patients. Cross-reacting anti-liraglutide antibodies to native glucagon-like peptide-1 (GLP-1) occurred in 6.9% of the VICTOZA-treated patients in the double-blind 52-week monotherapy trial and in 4.8% of the VICTOZA-treated patients in the double-blind 26-week add-on combination therapy trials. These cross-reacting antibodies were not tested for neutralizing effect against native GLP-1, and thus the potential for clinically significant neutralization of native GLP-1 was not assessed. Antibodies that had a neutralizing effect on liraglutide in an in vitro assay occurred in 2.3% of the VICTOZA-treated patients in the double-blind 52-week monotherapy trial and in 1.0% of the VICTOZA-treated patients in the double-blind 26-week add-on combination therapy trials. 

Antibody formation was not associated with reduced efficacy of VICTOZA when comparing mean HbA1c of all antibody-positive and all antibody-negative patients. However, the 3 patients with the highest titers of anti-liraglutide antibodies had no reduction in HbA1c with VICTOZA treatment. 

In five double-blind glycemic control trials of VICTOZA, events from a composite of adverse events potentially related to immunogenicity (e.g., urticaria, angioedema) occurred among 0.8% of VICTOZA-treated patients and among 0.4% of comparator-treated patients. Urticaria accounted for approximately one-half of the events in this composite for VICTOZA-treated patients. Patients who developed anti-liraglutide antibodies were not more likely to develop events from the immunogenicity events composite than were patients who did not develop anti-liraglutide antibodies.

In the LEADER trial [see Clinical Studies (14.3)], anti-liraglutide antibodies were detected in 11 out of the 1247 (0.9%) VICTOZA-treated patients with antibody measurements.

Of the 11 VICTOZA-treated patients who developed anti-liraglutide antibodies, none were observed to develop neutralizing antibodies to liraglutide, and 5 patients (0.4%) developed cross-reacting antibodies against native GLP-1. 

In a clinical trial with pediatric patients 10 to 17 years [see Clinical Studies (14.2)], anti-liraglutide antibodies were detected in 1 (1.5%) VICTOZA treated patient at week 26 and 5 (8.5%) VICTOZA treated patients at week 53. None of the 5 had antibodies cross reactive to native GLP-1 or had neutralizing antibodies.