Graybug Vision, a clinical stage pharmaceutical company developing potentially transformative long-acting therapies for ocular diseases including wet age-related macular degeneration (wet AMD), diabetic macular edema (DME), retinal vein occlusion (RVO), and primary open angle glaucoma (POAG), announced the initiation of its Phase 2a study with GB-102 in patients with macular edema (ME) secondary to DME or RVO.
GB-102, a pan-Vascular Endothelial Growth Factor (VEGF) inhibitor and potential twice-per-year therapy is targeted to reduce the need for frequent intravitreal injections in retinal diseases, including wet AMD, DME and RVO.
GB-102 seeks to reduce the significant treatment burden and sub-optimal visual outcomes experienced in real-world practice due to the challenge patients face in visiting the retinal specialist several times a year for needed injections and eye examinations.
The GB-102 Phase 2a open label, six-month study is intended to establish the safety of GB-102 and provide preliminary evidence of its durability in ME patients secondary to DME and RVO. It will enroll 20 ME patients at six centers in the US. They will be treated with a single intravitreal injection of 1 mg or 2 mg of GB-102, Graybug Vision’s microparticle depot formulation of sunitinib malate.
“DME and RVO frequently cause irreversible vision loss in older adults and currently available treatments are extremely burdensome for patients, their caregivers, and treating physicians due to the need for frequent intravitreal injections,” said Fred Guerard, President and Chief Executive Officer of Graybug Vision. “With its potential of a twice-per-year therapy, GB-102 could substantially transform patient outcomes and improve the current clinical practice.”
GB-102 completed a Phase 1/2a study (ADAGIO study) in Q1 2019 in which it met its primary endpoint of safety and tolerability and provided evidence of a durable biological signal of six-months or longer from a single intravitreal injection in wet AMD patients.
GB-102 is Graybug Vision’s microparticle depot formulation of sunitinib malate for intravitreal (IVT) injection. The formulation consists of microparticles made from poly-lactic-co-glycolic acid (PLGA) combined with the company’s proprietary surface treatment designed to eliminate inflammation typically associated with ocular administration of PLGA. The surface treatment facilitates microparticle aggregation upon IVT injection to form an implant-like depot in the inferior vitreous. After IVT injection, the microparticles gradually release sunitinib malate and biodegrade into lactic and glycolic acid which are naturally cleared from the body.
Sunitinib malate is a small molecule receptor tyrosine kinase inhibitor that is a potent inhibitor of VEGFR-1, -2, and -3, receptors known to play an influential role in the development and progression of wet AMD.
The ADAGIO clinical trial was an open-label, single dose study with 32 patients from eight centers located in the United States completed in January 2019. Patients enrolled in the study were previously treated with at least three prior IVT injections of an anti-VEGF agent (aflibercept, bevacizumab or ranibizumab). They received a single intravitreal dose of GB-102 (0.25, 0.5, 1, or 2 mg) in escalating dose cohorts with eight patients in each cohort. They were followed monthly for eight consecutive months. Depending on the dosages, between 50 and 88% of subjects required no additional IVT injections of any anti-VEGF for six months after a single administration of GB-102.
Wet AMD is the leading cause of blindness in the developed world in individuals aged 50 years or older. It is caused by the formation of abnormal and leaky new blood vessels behind the retina, termed choroidal neovascularization. The leakage of fluid and protein from the vessels causes retinal degeneration and leads to severe and rapid loss of vision. According to the National Eye Institute, the prevalence of wet AMD among adults 40 years or older in the United States alone is estimated at 1.75 million people. In addition, an estimated 20 million adults are affected by wet AMD worldwide.
Source: Company Press Release