Anti-Vascular Endothelial Growth Factor Activity in the Bevacizumab and Triamcinolone Acetonide Combination for Intravitreal Use

Abstract

Purpose

To find out if the combination for intravitreal use of the antibody bevacizumab (AvastinTM; Genentech, Inc., San Francisco, CA) and triamcinolone acetonide (TA) (Kenacort®; Bristol-Myers Squibb, Anagni, Italy) could affect over time the anti–vascular endothelial growth factor (VEGF) activity of bevacizumab.

Methods

Two different combined preparations were obtained, drawing up together 1.25 mg/0.05 mL of bevacizumab and 2 mg/0.05 mL (B+TA_2mg) or 4 mg/0.05 mL (B+TA_4mg) of TA into insulin syringes with 29-G needle. Control preparations were obtained with bevacizumab and an injectable solution (B). The syringes were stored refrigerated at 4°C. The bevacizumab concentration was measured, through its binding to VEGF-165 isoform, at 48 hours and at 1 week.

Results

No preparations showed statistically significant changes in bevacizumab concentration with time (p=0.74 for B+T_2mg, p=0.92 for B+T_4mg, p=0.57 for B). The B+TA2mg preparations showed a larger percentage of degradation of bevacizumab than the B+TA4mg preparations (28.4% versus 17.6% at 48 hours; 26.4% versus 18% at 1 week). The B control preparations showed the lowest drug degradation: 9.6% at 48 hours and 14.8% at 1 week.

Conclusions

After storage at 4°C for 48 hours and 1 week, the combined preparations showed a larger reduction in bevacizumab concentration than the control preparations. No significant change was observed with the length of storage. The preparations obtained mixing 4 mg/0.05 mL of TA and 1.25 mg/0.05 mL of bevacizumab maintained the highest anti-VEGF activity over time. (Eur J Ophthalmol 2009; 19: 842–7)