Pharmacokinetics and Safety of an Intravitreal Humanized Anti-VEGF-A Monoclonal Antibody (PRO-169), a Biosimilar Candidate to Bevacizumab

BACKGROUND: PRO-169 is a biosimilar candidate to bevacizumab (BEV), a monoclonal antibody (mAb) that inhibits vascular endothelial growth factor-A (VEGF-A) developed for intravitreal use. The current study demonstrates the intraocular pharmacokinetics (PK) of PRO-169 and its safety using New Zealand white (NZW) rabbits. METHODS: Intraocular concentration was evaluated in thirty-six rabbits at 1h, 1, 2, 5, 14 and 30 days after a single bilateral injection of PRO-169 or BEV (1.25 mg/0.05 mL). In a secondary experiment, safety was evaluated after three consecutive unilateral injections at 30-day intervals in twenty-four rabbits (PRO-169: 1.25 mg/0.05 mL or ranibizumab [RZB]: 0.5 mg/0.05 mL), by liver-associated enzymes (LAE), ophthalmological examination and adverse event (AE) incidence. Primary endpoints were vitreous maximum concentration (C(max)), time to attain maximum concentration (t(max)), area under curve (AUC(0-t)), half-life (t(1/2)) and LAE. Secondary endpoints included aqueous humor (AH) and plasma pharmacokinetics, clinical examination and AEs. RESULTS: The C(max) in the vitreous was 593.75 ± 45.63 (PRO-169) vs 644.79 ± 62.65 µg/mL (BEV) (p= 0.136). T(max) was 0.53 ± 0.82 vs 0.85 ± 0.73 days (p= 0.330). The AUC(0-t) was 3837.72 ± 465.91 vs 4247.31 ± 93.99 days*µg/mL (p= 0.052) and the half-life was 4.99 ± 0.89 vs 5.18 ± 0.88 days (p= 0.711). LAEs were normal in 92% of NZW rabbits; no differences between groups were observed (p>0.05). The AH and plasma PKs were also similar. Finally, clinical examinations found no alterations. AEs were observed in 25% of PRO-169 rabbits, without differences vs RZB (p=0.399). CONCLUSION: PRO-169 can be efficiently diffused and distributed in ocular compartments, showing vitreous pharmacokinetics analogous to BEV. The safety experiment did not find evidence of clinical alterations from a repeated injection of PRO-169. These results provide scientific justification supporting that PRO-169 should be evaluated in future clinical trials to confirm its safety and efficacy.