FovistaTM Anti-PDGF Therapy
FovistaTM is designed to target platelet derived growth factor (PDGF) in combination with anti-VEGF drugs to disrupt the formation of abnormal new blood vessels in wet AMD. In clinical trials, the combination of FovistaTM 1.5mg and an anti-VEGF therapy demonstrated statistically significant superiority compared to anti-VEGF monotherapy in terms of improvements in visual acuity, providing a 62% comparative benefit from baseline.
FovistaTM binds to and inhibits PDGF expression, causing the loss or stripping of pericytes, leaving the endothelial cells unprotected and highly vulnerable to the effects of anti-VEGF therapy. Clinical data have shown that administration of FovistaTM 1.5mg in combination with anti-VEGF drugs is likely to inhibit new blood vessel growth in patients with wet AMD more effectively than anti-VEGF monotherapy and may also enhance neovascular regression.
ZimuraTM – Anti-Complement
ZimuraTM targets complement factor C5, a central component of the complement cascade that is believed to be involved in the development of AMD. In a Phase 2a clinical trial of ZimuraTM, wet AMD patients who had not previously been treated with anti-VEGF therapy and who received six injections of ZimuraTM in combination with anti-VEGF treatment showed improvements in vision of a magnitude warranting further evaluation in subsequent studies.
Based on results of this trial, data from a third-party clinical trial and multiple published studies suggesting that the complement pathway plays a significant role in dry AMD, we plan to initiate a Phase 2/3 clinical trial investigating ZimuraTM for treatment of geographic atrophy, a severe form of dry AMD affecting approximately 8 million patients worldwide. In addition, a Phase 2 clinical trial is planned for Zimura™ and Fovista™ in combination with anti-VEGF therapy for the treatment of anti-VEGF resistant wet AMD patients believed to have complement-mediated inflammation.
Ophthotech is evaluating a study of ZimuraTM in combination with anti-VEGF therapies in patients with wet AMD who do not respond adequately to treatment with anti-VEGF monotherapy on the basis of complement mediation inflammation.
Both FovistaTM and ZimuraTM are aptamers, single strands of nucleic acid that bind with high specificity and affinity to targets such as PDGF, similar to a monoclonal antibody. Aptamers are synthetically derived, making their production predictable and reproducible. They are also chemically stable and do not generate an immune response that could limit efficacy.