ABSTRACT
PURPOSE: 5-HT(1A) agonists are neuroprotective in CNS injury models. The authors evaluated the efficacy of 5-HT(1A) agonists to protect the retina from severe blue light-induced photo-oxidative damage. METHODS: Albino rats were dosed (subcutaneously) with AL-8309A, 8-OH DPAT, or buspirone once or three times before 6-hour exposure to blue light. Electroretinograms (ERGs) were measured to assess retinal function, and retinal damage was evaluated by light microscopy. Topical ocular dosing with 1.75% AL-8309B was also evaluated. Rats were dosed with WAY-100635, a 5-HT(1A) antagonist, to determine whether protection required activation of the 5-HT(1A) receptor. RESULTS: ERG response amplitudes were significantly (P < 0.05) depressed more than 66% in vehicle-dosed rats after light exposure. ERGs were significantly higher in rats treated with AL-8309A (0.1-30 mg/kg), 8-OH DPAT (0.1-1 mg/kg), buspirone (5-20 mg/kg) or topical ocular with 1.75% AL-8309B. Retinas from AL-8309A and 8-OH DPAT-treated rats were devoid of histologic lesions. Significant protection was measured in rats dosed once 0, 24, or 48 hours before light exposure. Protection provided by dosing with AL-8309B or 8-OH DPAT was inhibited in rats predosed with WAY-100635. CONCLUSIONS: 5-HT(1A) agonists provided potent and complete functional and structural protection. Protection was inhibited by treatment with WAY-100635, confirming the requirement for activating the 5-HT(1A) receptor in initiating this survival pathway. Single-dose experiments with AL-8309A suggest that the mechanism of protection is rapidly activated and protection persists for 48 hours. AL-8309B (1.75%) was effective after topical ocular dosing. AL-8309B is under evaluation in the clinic and may be useful in treating age-related macular degeneration.
Subject(s)
Light , Radiation Injuries, Experimental/prevention & control , Retina/radiation effects , Retinal Degeneration/prevention & control , Serotonin 5-HT1 Receptor Agonists/pharmacology , Animals , Buspirone/pharmacology , Dark Adaptation , Dose-Response Relationship, Drug , Electroretinography , Male , Oxidative Stress , Piperazines/pharmacology , Pyridines/pharmacology , Radiation Injuries, Experimental/etiology , Rats , Rats, Sprague-Dawley , Receptor, Serotonin, 5-HT1A/metabolism , Retina/drug effects , Retinal Degeneration/etiology , Serotonin Antagonists/pharmacologyABSTRACT
PURPOSE: To evaluate safety and efficacy of the angiostatic agent anecortave acetate, compared with a placebo, for treatment of subfoveal choroidal neovascularization (CNV). DESIGN: Ongoing masked, randomized, placebo-controlled, parallel evaluation of anecortave acetate (30 mg, 15 mg, and 3 mg) versus a placebo. PARTICIPANTS: There were 128 eyes of 128 patients with subfoveal CNV secondary to age-related macular degeneration who were enrolled and treated, with 80% (102/128) of eyes presenting with predominantly classic lesions at baseline. METHODS: All eyes received a posterior juxtascleral depot application of masked study medication or a placebo, with retreatment at 6-month intervals if the masked investigator believed the patient could benefit. Patients received periodic detailed ophthalmic examinations with both fluorescein and indocyanine green angiography, general physical examinations with electrocardiograms, and hematology/serum chemistry/urinalysis. All ophthalmic and systemic safety data were periodically reviewed by the Independent Safety Committee overseeing the study. MAIN OUTCOME MEASURES: Best-corrected logarithm of the minimum angle of resolution (logMAR) vision and fluorescein angiographic lesion characteristics were compared over time and among treatment groups. RESULTS: At month 12, anecortave acetate (15 mg) administered at 6-month intervals was statistically superior to the placebo for 3 measures of clinical efficacy: mean change from baseline vision (P = 0.0131), stabilization of vision (<3 logMAR line change; P = 0.0323), and prevention of severe vision loss (decrease of > or = 6 logMAR lines from baseline; P = 0.0224). Subgroup analysis of predominantly classic lesions revealed that anecortave acetate (15 mg) was also superior to the placebo at 1 year for each of these 3 measures of visual outcome (Ps = 0.0022, 0.0100, and 0.0299, respectively). Anecortave acetate (15 mg) trended toward significance over the placebo at month 12 for inhibition of total lesion growth and for inhibition of both the total CNV component and the classic CNV component in both the overall and subgroup analyses. The Independent Safety Committee identified no clinically relevant treatment-related safety issues. CONCLUSIONS: Anecortave acetate (15 mg) is safe and clinically efficacious at 1 year for maintaining vision, preventing severe vision loss, and inhibiting subfoveal CNV lesion growth.
