Method for treating retinal diseases with a carbonic anhydrase inhibitor

Abstract

The present invention is directed to a method for treating retinal diseases with genetically driven retinoschisis. The retinal diseases suitable to be treated by the present invention for example include X-linked retinoschisis (XLRS) and other genetically driven diseases with retinoschisis. The method comprises the step of administering an effective amount of a carbonic anhydrase inhibitor (CAI), or a pharmaceutically acceptably salt or prodrug thereof, to the posterior segment of the eye of a subject in need thereof, via intravitreal injection.

Description

[0001] METHOD FOR TREATING RETINAL DISEASES WITH A CARBONIC ANHYDRASE INHIBITOR

[0002] FIELD OF THE INVENTION

[0003] The present invention relates to methods for treating retinal diseases with genetically driven retinoschisis such as X-linked retinoschisis (XLRS). The method comprises administering a carbonic anhydrase inhibitor (CAI) intravitreally to a subject in need thereof.

[0004] BACKGROUND

[0005] The treatment of many inherited retinal diseases presents significant challenges due to either the absence of approved therapies or the reliance on eye drops, which are ineffective or have insufficient efficacy for the long-term treatment of retinal conditions. One published study reported a strikingly low adherence rate of only 28.18% among patients using CAIs, emphasizing the significant challenges of maintaining medication consistency driven by factors such as side effects and complex treatment protocols. Eye drops are also associated with significant drug wastage and low bioavailability. with less than 5% of the administered dose reaching intraocular tissues due to precorneal drainage and limited comeal absorption and even less reaching the posterior retina.

[0006] XLRS is a rare hereditary retinal disease affecting between 1 in 5,000 to 1 in 20,000 males. It is caused by mutations in the RSI gene, which encodes retinoschisin, a 224-amino acid protein expressed by many retinal cells, most prominently in photoreceptor cells, except the retinal pigment epithelium (RPE) and glial cells, such as Muller cells. Retinoschisin is essential for cell-cell interaction mediating intercellular adhesion and thereby maintaining retinal structure as well as photoreceptor-bipolar cell synaptic structure and signaling.

[0007] Structurally, assessed via optical coherence tomography (OCT), XLRS is characterized by splitting of the retinal layers, leading to the formation of cystic spaces in the macula (central retina) and functionally by a diminished b-wave and altered a-wave / b-wave ratio, assessed via electroretinography (ERG), resulting in significant visual impairment. Cystic spaces which form in the peripheral retina and cystoid macular edema (CME) are also characteristic of this disease, which may lead to further complications, including vitreous hemorrhage, retinal detachment and neovascular glaucoma.

[0008] 1

[0009] 185416057 1Other inherited retinal diseases that are characterized by presence of retinoschisis include retinitis pigmentosa (RP) which is a group of inherited retinal dystrophies that affect approximately 1 in 4.000 people worldwide leading to a gradual loss of vision and eventually blindness; pseudophakic Cystoid Macular Edema (PCME) which is the most common cause of visual acuity deterioration after uncomplicated cataract surgery: cystoid macular edema (CME) is attributed to other health conditions, such as retinal vein occlusion, uveitis, or diabetes.

[0010] Carbonic anhydrases (CA) are a family of enzymes that catalyze the reaction between carbon dioxide and water resulting in the formation of protons (H+ions) and bicarbonate (HCCh ) ions. These enzy mes regulate the cytosolic and extracellular acid-base balance (pH homeostasis) and provide substrates to specific ion transporters and ion channels that shuttle protons and bicarbonate ions, along with sodium ions, across cell membranes. The movement of the above-mentioned ions is associated with fluid movement across the cell membrane and epithelial layers where CA is expressed.

[0011] Several different CA isoforms and bicarbonate transport proteins are present in the retinal pigment epithelium (RPE). CA isoforms are expressed in the cytosol (CA II), on the apical (CA IV, CA IX, CA XII, CA XIV) and basolateral (CA IX) membranes. Dorzolamide has been reported to decrease steady-state fluid absorption in cultured human fetal RPE. In some patients with macular edema, systemic acetazolamide has been shown to increase fluid clearance from the subretinal space. These reports are suggestive of CA-mediated fluid transport across the RPE.

[0012] Additionally, inhibition of CA exerts potent vasodilator effects in the brain and other vascular beds such as retinal and choriocapillaris, for example. As a result, hemodynamic effects of topical dorzolamide and brinzolamide have been extensively studied. Brinzolamide as well as dorzolamide have been found to increase Optic Nerve Head (ONH), choroidal and retinal blood flow in patients with glaucoma and experimental animals in several studies. One study indicated that treatment with dorzolamide normalizes retinal blood flow regulation in patients with glaucoma. This is in agreement with data showing that a 6-month treatment with dorzolamide normalizes the ocular pressure / flow relationship.

[0013] In the ciliary epithelium of the anterior segment of the eye, CA activity is important for aqueous humor production. Topical carbonic anhydrase inhibitors, therefore, reduce aqueous humor formation. Brinzolamide and dorzolamide are currently approved for reducing intraocular pressure (IOP) in subjects with glaucoma or ocular hypertension and 2

[0014] 185416057 1provide an efficacy between 15% and 20% from the initial IOP value. To effect the reduction of IOP, dorzolamide 2% and brinzolamide 1% are administered topically to the eye. Target tissue is the ciliary body epithelium, which is responsible for aqueous humor production and secretion in order to affect fluid flow across that epithelium, aqueous humor production, and IOP. That tissue is in the anterior segment of the eye, close to the cornea and conjunctiva / sclera where the eye drop is administered. For that treatment, the drug formulation is designed to have a short diffusion path to its target tissue.

[0015] Table 1 describes the inhibitory potencies of compounds of this invention, as Ki values in nanomolar concentration, against CA isoforms present in the eye.

[0016] Table 1. CA isozy me inhibition (Ki(nM))

[0017]

[0018] CA: carbonic anhydrase; h: human; b: bovine

[0019] US 7.829,065 (Supuran et al);aITRM990414 (Supuran et al);bDeSantis et al, Surv Ophthalmol 2000;cIUPHAR-BPS Guide to PHARMACOLOGY;dAngeli et al, Molecules 2021

[0020] Frequent eye drop use can cause adverse effects such as stinging, inflammation, and blurred vision, exacerbating ocular surface issues and reducing adherence to prescribed regimens. These limitations are particularly detrimental for rare retinal diseases, where consistent therapeutic levels are critical to preserving vision. For pediatric and dependent populations, caregiver involvement further complicates adherence, emphasizing the need for alternative delivery methods.

[0021] Intravitreal administration provides more direct access to the retina and other tissues in the posterior segment of the eye than topical administration. The challenge with intravitreal injections is that a solution formulation has a short half-life for clearance from the vitreous,

[0022] 3

[0023] 185416057 1particularly for a small molecule but also for a biologic drug, that requires frequent reinjections. Examples of biologic drugs include VEGF-inhibitors approved for the treatment of age-related macular degeneration (AMD) and diabetic macular edema (DME). such as, for example, ranibizumab and aflibercept, as well as bevacizumab which has been used off-label. Clerance from the vitreous of a suspension formulation administered intravitreally, and duration of a pharmacodynamic effect, largely depend on the dissolution kinetics of the suspended particles. As a result, tuning of the vitreal clearance of suspension formulations has limitations and is largely dependent on the administered dose. Furthermore, intravitreally administered suspension formulations can obstruct vision if they diffuse into the central light path to the macula.

[0024] There is a need for an effective method to treat rare retinal diseases, which can achieve more targeted treatment and fewer side effects than topical eye drops.

[0025] BRIEF DESCRIPTION OF THE DRAWNGS FIGs. 1A-1C show the chemical structures of CAIs useful for the present method.

[0026] DETAILED DESCRIPTION OF THE INVENTION

[0027] The present invention is directed to a method for treating retinal diseases with genetically driven retinoschisis, affecting the back of the eye, also know n as the posterior segment of the eye. The retinal diseases suitable to be treated by the present method include, but are not limited to, X-linked retinoschisis associated with mutations in the RS J gene; CRB 1 -associated retinal dystrophies, including (7 / 7 / -related retinitis pigmentosa and Leber congenital amaurosis; retinal diseases associated with NR2E3, including enhanced S-cone syndrome and aty pical retinitis pigmentosa; inherited retinal degenerations characterized by chronic intraretinal schisis. cystic retinal splitting, or schisis-like retinal changes, including various forms of retinitis pigmentosa and macular dystrophy associated with mutations in USH2A, EYS, PRPF31, RHO, IMPDH1, RPGR, CRX, GUCY2D, PROMI, and CDHRE, juvenile X-linked macular dystrophy; other cone-rod or rod-cone dystrophies; and less common genetic disorders in which schisis-like retinal changes have been described, including Alport-related retinopathy associated with mutations in COL4A3, COL4A4. or COL4A5 and Goldmann-Favre syndrome, as well as any other inherited or heritable retinal disorder, whether presently known or later identified, in which genetically driven

[0028] 4

[0029] 185416057 1retinoschisis, intraretinal cyst formation, or schisis-like structural separation of retinal layers occurs in the posterior segment of the eye.

[0030] The present method comprises the step of administering an effective amount of a carbonic anhydrase inhibitor (CAI) such as dorzolamide or brinzolamide, or a pharmaceutically acceptably salt or prodrug thereof, to the posterior segment of the eye of a subject in need thereof, via intravitreal injection.

[0031] Suitable CAIs for the present method include dorzolamide, brinzolamide, acetazolamide, methazolamide, ethoxzolamide, MK 0927, or sezolamide, or pharmaceutically acceptably salts or prodrugs thereof.

[0032] Further suitable CAIs for the present invention include Compound 8; Compound 9; Compound 10, or pharmaceutically acceptably salts or prodrugs thereof. The chemical structures of the above-mentioned CAIs are shown in FIG. 1.

[0033] Compounds 8, 9 and 10 have certain structural features, such as a hydroxyl group in Compounds 8 and 9 or a carboxylic acid group in Compound 10, that are distinct from the amino functionalities in dorzolamide, brinzolamide, acetazolamide, methazolamide, ethoxzolamide, MK 0927, or sezolamide. For Compounds 8, 9 and 10, the distinction lies in the chemical nature of the bonds between the active CAI molecule and the sustained-release matrix compared to the “amino” CAIs. CAIs with hydroxyl (-OH) or carboxylic acid (-COOH) groups can form covalent ester bonds with an appropriate linker, whereas those with primary7or secondary amino (-NFL or -NH-, respectively) groups can form covalent amide bonds.

[0034] Independently, the sulfonamide moiety shared in all of the CAIs of the present method is also amenable to be bonded to the implant polymer matrix. These covalent bonds are cleaved by different enzy mes in the body: esterases break down esters, while amidases cleave amides.

[0035] Alternatively, the hy drogen atom in a hydroxyl group can act as a hydrogen bond donor for an interaction with a hydrogen bond acceptor that has greater electronegativity, such as a free electron pair in a nitrogen or an oxygen atom for example. According to the IUPAC nomenclature, the hydrogen bond donor is referred to as a proton donor, the hydrogen bond acceptor as a proton acceptor. Such molecular interactions between a hydrogen bond donor and a corresponding acceptor are not covalent bonds. However, they exhibit partial covalent character with stronger attraction than a simple electrostatic van der Waals interaction.

[0036] Consequently, hydrogen bond interactions do not require enzy matic activity (esterases, amidases) for separation of the donor from the acceptor in a biological system.

[0037] 5

[0038] 185416057 1Similarly, primary' and secondary amines can act as hydrogen bond donors and interact with a free electron pair of a nitrogen or oxy gen atom in an acceptor. But the strength of this interaction is weaker than between a hydroxyl group as donor and a nitrogen atom as acceptor.

[0039] As a result, the type of functional group in a CAI molecule directly affects how it can be bonded (covalently or by hydrogen bond) to a matrix linker and the rate and mechanism of drug release in vivo, influencing both pharmacokinetics and therapeutic efficacy. The hydroxyl and carboxylic acid group containing CAIs expand the repertoire of linkers for attachment beyond the ‘"amide” CAIs and expand the options for fine-tuning the release rate of the active CAI and the stability of the sustained-release device or implant.

[0040] In one embodiment, the CAI is contained in a biodegradable implant, and is released between 0.1 and 15 pg / day, or preferably between 0.2 and 10 pg / day or between 0.3 and 3 pg / day. In some embodiments, the release rate is about 0.1 pg / day, 0.2 pg / day, 0.3 pg / day, 0.4 pg / day, 0.5 pg / day, 0.6 pg / day, 0.7 pg / day, 0.8 pg / day, 0.9 pg / day, 1 pg / day, 1.5 pg / day, 2 pg / day, 2.5 pg / day, 3 pg / day, 3.5 pg / day, 4 pg / day, 4.5 pg / day, 5 pg / day, 5.5 pg / day, 6 pg / day, 6.5 pg / day, 7 pg / day, 7.5 pg / day, 8 pg / day, 8.5 pg / day, 9 pg / day, 9.5 pg / day, 10 pg / day, 11 pg / day, 12 pg / day, 13 pg / day, 14 pg / day, 15 pg / day.

[0041] In one embodiment, the CAI is released over a duration period of three months or longer, preferably 6 months or longer, and more preferably 12 months or longer. In some embodiments, the CAI is released over a period of about 3 months, 4 months, 5 months, 6 months, 7 months, 8 months, 9 months, 10 months, 11 months, 12 months, 15 months, 18 months, 21 months, 24 months.

[0042] In one embodiment, the CAI achieves a maximal concentration (Cmax) in the nonpigmented posterior retina between 0.02 and 20 pg / g tissue, or preferably between 0.1 and 10 pg / g tissue.

[0043] It is difficult to achieve sufficient drug levels in the retina from topical administration to produce a pharmacodynamic effect, since a topically administered drug has a long diffusion path and has to cross multiple layers and barriers of the eye in order to reach the retina, including i) the cornea; ii) conjunctiva and sclera; iii) a highly vascularized choroid that absorbs drugs and transports them out of the eye and into the general circulation; iv) Bruch’s membrane; and v) melanin in the choroid and RPE which can non-specifically bind and trap drugs, particularly small molecules, preventing them from reaching their intended target.

[0044] 6

[0045] 185416057 1The present invention administers a CAI by intravitreal injection of a biodegradable implant to the eye of a subject. The present method provides several months of therapy from a single injection. The implant may be miniaturized to adequately address smaller eyes, including pediatric patients and children. An implant of lesser size can be delivered intravitreally using a small injector or fine needle gauge syringe to minimize potential complications and patient discomfort. The biodegradable, bioresorbable implant is fully absorbed in the body to minimize or eliminate residual material in the eye while obviating the need for surgical removal or explantation.

[0046] The present method enables the administration of a greater amount of CAI to the retina than that achievable with topical 2% dorzolamide or 1% brinzolamide eye drops administered 2-3 times daily, thereby improving the clinical effects. The greater concentrations of CAI delivered produce better vision, less retinoschisis, and less retinal degeneration. This improvement in vision benefits patients more than attainable with current therapies such as dorzolamide 2% eye drops administered 2-3 times daily or brinzolamide 1% eye drops administered 2-3 times daily, or acetazolamide given in a daily dose of 10 - 15 mg / kg divided into 2-4 doses. The greater concentrations of CAIs in the retina also result in better improvement in retinal structure and less retinal degeneration, including fewer retinal detachments and hemorrhages.

[0047] The present method administers a CAI in a biodegradable sustained release intravitreal implant. The implant provides controlled, sustained, targeted delivery of a CAI to the retina and RPE. thereby improving patient compliance for consistent, long-term treatment, in contrast to the frequent dosing requirement of eye drops.

[0048] In one embodiment, the biodegradable CAI implant used in the present method is designed based on a biodegradable polymer prodrug system, where the drug is chemically bound to a polymer backbone, as described in US Patent No. US 11,207,417, which is incorporated herein by reference in its entirety. The polymer matrix is designed to provide sustained, controlled drug release as it degrades through hydrolysis, allowing for targeted delivery' over extended periods. This approach eliminates the need for excipients, minimizes dosing frequency, and is well-suited for localized treatment in ocular diseases.

[0049] In another embodiment, the biodegradable CAI implant used in the present method includes a platform described in Publication No. WO2023 / 079362, which is incorporated herein by reference in its entirety7. The biodegradable CAI implant includes chemically engineered CAI and prodrugs that undergo surface erosion, which provides zero-order release 7

[0050] 185416057 1kinetics. The CAI is released at a constant rate over time, allowing for precise control over both the dosage and duration of drug delivery'. This CAI implant is absent of polymers or excipients in the delivery system, which eliminates pro-inflammatory degradation products and supports repeat dosing and potentially improving patient outcomes.

[0051] In yet another embodiment, the biodegradable CAI implant used in the present method includes a platform of an implantable bioerodible device, described in Publication No. US 2022 / 0202724, which is incorporated herein by reference in its entirety, where the CAI is incorporated into a tubular drug core covered by one or more than one bioerodible polymeric outer layers substantially surrounding the drug core. The outermost layer is permeable to the CAI and contains at least one delivery port providing a substantially constant release of the CAI over an extended period of time. If present, an inner layer may not be permeable to the CAI. Sealing one, both or neither end of the device with a polymer impermeable to the CAI contributes to the overall release rate of the CAI and durability of the device in the vitreous.

[0052] In yet another embodiment, the biodegradable CAI implant used in the present method includes a platform that utilizes a polyethylene glycol (PEG)-based hydrogel matrix, cross-linked with a biodegradable linker to encapsulate and release the CAI. The hydrogel is designed for sustained, controlled drug delivery, gradually degrading through hydrolysis while releasing the therapeutic agent over time. This approach minimizes dosing frequency and improves patient compliance in retinal disease treatments. The platform is described in US Publication No. 2023 / 0285282, which is incorporated herein by reference in its entirety.

[0053] In yet another embodiment, the biodegradable CAI implant used in the present method includes a non-erodible, sustained-release intravitreal drug delivery' system designed to provide controlled, long-term release of therapeutic agents directly into the vitreous cavity of the eye. The system consists of a biocompatible polymeric matrix embedded with the drug, which enables the delivery of consistent therapeutic concentrations over an extended duration. The system is described in US Publication No. 2012 / 0016467, which is incorporated herein by reference in its entirety.

[0054] In yet another embodiment, the CAI implant used in the present method includes a small port delivery system (PDS), such as Susvimo® (Genentech) or similar devices described in Publication No. WO 2017 / 176886, which is incorporated herein by reference in its entirety', with a reservoir of up to 0.02 mL of medication. The PDS is designed to be surgically implanted outside of the visual axis in the supratemporal or supranasal region of 8

[0055] 185416057 1the anterior sclera at the level of the pars plana. As a trans-scleral ocular implant, the PDS is externally refillable through a self-sealing septum on the extrascleral surface with approximately 0.01 mL of a CAI solution suitable for intravitreal delivery using a 34G or similar size needle. Repeated refill-exchange procedures post implantation allow replenishment of the device’s store, provide for extended, controlled, continuous passive diffusion of the CAI into the vitreous cavity7and reduce the treatment burden of repeated intravitreal injections improving patient compliance, convenience and safety.

[0056] In the present method, the biodegradable CAI implant composition is designed to achieve zero-order, near-zero-order, or high-order drug release kinetics.

[0057] In one embodiment, the amount of CAI is between 0.01 and 2 mg per implant.

[0058] In one embodiment, the size of the implant is from 3 to 15 mm in length and from 0.05 to 1 mm in diameter; with a more preferred size of 5 to 10 mm in length and 0.08 to 0.7 mm in diameter.

[0059] The present method provides sufficient therapeutic CAI level to reduce retinal cystic spaces caused by fluid accumulation.

[0060] In one embodiment, a CAI is released from the implant at a controlled rate of between 0.1 to 15 pg / day; with a more preferred controlled release rate of between 0.2 and 10 pg / day.

[0061] In another embodiment, the CAI achieves a maximal concentration (Cmax) in the nonpigmented posterior retina between 0.02 and 20 pg / g tissue, or preferably between 0.1 and 10 pg / g tissue.

[0062] In a preferred method, the biodegradable implant is fully absorbed in the eye and leaves little to no residual material in the eye after therapeutic release.

[0063] In one embodiment, the biodegradable implant is injected using a needle, for example, with a gauge between 22G and 34G, or between 25G and 33G to minimize potential complications and discomfort.

[0064] In one embodiment, the biodegradable implant is injected using a 27G needle.

[0065] In one embodiment, the biodegradable implant is formulated in a pro-drug format including polymers such as polylactic-co-gly colic acid (PLGA) or other biodegradable materials.

[0066] In one embodiment, the biodegradable implant is formulated in a pro-drug format including polyethylene glycol (PEG) polymers or other biodegradable materials.

[0067] In one embodiment, the present method is initiated early in the patient’s life to prevent disease progression and maintain visual function.

[0068] 9

[0069] 185416057 1The present method provides the following advantages over the existing methods of topical or systemic administration of a CAI:

[0070] • Better clinical effect with greater improvement in vision and greater reduction in retinoschisis

[0071] • Decrease in the incidence of retinal detachments, hemorrhages and retinal necrosis

[0072] • Eliminates the need for frequent eye drop administration, improving adherence, particularly for pediatric and dependent populations.

[0073] • Reduces systemic drug levels and potential systemic unwanted effects.

[0074] • Removes variability in dosing, enabling clinicians to monitor treatment durability and determine patient responsiveness reliably.

[0075] • Reduces drug waste and minimizes ocular surface-related adverse effects like stinging, inflammation, and blurred vision.

[0076] • Provides longer-lasting effects and fewer interventions.

[0077] • Utilizes an implant that is nearly or fully degradable at the time in which therapeutic benefit is realized, minimizing concerns about long-term residual material in the vitreous.

[0078] EXAMPLES

[0079] Compound 8 can be synthesized using the synthesis described in US Patent No. 7,829,065, Example 21.

[0080] Compound 9 can be synthesized using the synthesis described in Canadian Patent No.

[0081] 2,361,906, Example 23.

[0082] Compound 10 can be synthesized using the synthesis described in US Patent No. 7,829,065, Example 26.

[0083] Example 1. Posterior Segment Exposure of Dorzolamide Following Topical Administration to the Rabbit Eye (Prophetic example, for comparison purpose)

[0084] Four Dutch-Belted rabbits weighing approximately 2.5 kg are being topically treated in both eyes with one drop (30 pL) each of dorzolamide-HCL ophthalmic solution three times per day for 6 days, followed by one morning dose on day 7. Two animals each are sacrificed at 1 hour and 8 hours after the final topical dose, respectively. Both eyes are enucleated immediately after sacrifice and frozen in liquid nitrogen. The frozen eyes are 10

[0085] 185416057 1hemisected equatorially and the vitreous humor, followed by retina, RPE / choroid and sclera harvested from the posterior segment. A plasma sample is obtained at termination as well. All tissues and fluids are stored at -80 °C until analysis. The content and concentration of dorzolamide in each tissue and fluid harvested is analyzed with a qualified LC-MS / MS bioanalytical method. Drug levels are expressed as mg / mL or mg / g as appropriate.

[0086] Example 2. Determination of the Pharmacokinetics from Rabbit Vitreous and Posterior Segment Exposure of Dorzolamide Following Intravitreal Administration (Prophetic Example)

[0087] Ten Dutch-Belted rabbits weighing approximately 2.5 kg receive a single 50 pL intravitreal injection of a solution containing 5 pg dorzolamide in both eyes. At 4, 8, 24, 48 and 72 hours later 2 rabbits per timepoint are sacrificed. Both eyes are enucleated immediately after sacrifice and frozen in liquid nitrogen. The frozen eyes are hemisected equatorially and the vitreous humor, followed by retina, RPE / choroid and sclera harvested from the posterior segment. A plasma sample is obtained at termination as well. All tissues and fluids are stored at -80 °C until analysis. The content and concentration of dorzolamide in each tissue and fluid harvested is analyzed with a qualified LC-MS / MS bioanalytical method. Drug levels are expressed as mg / mL or mg / g as appropriate. A non-compartmental PK analysis is being performed to obtain Cmax, Tmax, Tl / 2, AUCO-24 and AUCO-a values for dorzolamide in vitreous humor.

[0088] Example 3. Determination of CAI-Implant Pharmacokinetics and Posterior Tissue Exposure to CAI in Rabbits (Prophetic Example)

[0089] Three distinct CAI-implants with unique compositions and CAI release kinetics, aiming for zero-order release kinetics, are being investigated in 36 Dutch-Belted rabbits weighing approximately 2.5 kg. Each implant is administered once intravitreally in both eyes of 12 rabbits. At 8 hours, 7, 14, 28, 42 and 84 days later 2 rabbits per implant and per timepoint are sacrificed. Both eyes are enucleated immediately after sacrifice and frozen in liquid nitrogen. The frozen eyes are hemisected equatorially and the vitreous humor, followed by retina, RPE / choroid and sclera harvested from the posterior segment. A plasma sample is obtained at termination as well. All tissues and fluids are stored at -80 °C until analysis. The content and concentration of dorzolamide in each tissue and fluid harvested is analyzed with a qualified LC-MS / MS bioanalytical method. Drug levels are expressed as mg / mL or mg / g as 11

[0090] 185416057 1appropriate. A non-compartmental PK analysis is being performed to obtain Cmax, Tmax, Tl / 2, AUCO-24 and AUCO-oo values for each CAI in vitreous humor.

[0091] Example 4. Safety Evaluation of a CAI-Implant Following Administration into the Rabbit Vitreous (Prophetic Example)

[0092] In this non-GLP safety study, three distinct CAI-implants with unique compositions and CAI release kinetics, aiming for zero-order release kinetics, and one blank implant (vehicle) are being investigated in 32 Dutch-Belted rabbits weighing approximately 2.5 kg. Each implant is administered once intravitreally in both eyes of 8 rabbits. During the in-life phase at prescreening (prior to implant administration) and on days 7, 14, 28, 42 and 84 post implant administration, as applicable, each rabbit is undergoing a comprehensive ophthalmic examination (slit-lamp biomicroscopy and indirect ophthalmoscopy) using a modified McDonald-Shadduck scoring system. At prescreening, only rabbits with scores of 0 (zero) for all variables are accepted into the study. Intraocular pressure is being recorded in each animal at prescreening, 4 hours post implant administration and on days 7, 14, 28, 42 and 84 post implant administration, as applicable. Cage-side observations include monitoring of food and water consumption, body weight, signs of illness, distress and mortality. At 14, 28, 42 and 84 days post implant administration 2 rabbits per implant and per timepoint are sacrificed. Both eyes including ocular adnexa (eyelids, harderian and lacrimal glands) are enucleated immediately after sacrifice, with the 12 o’ clock position marked to maintain subsequent orientation. Both glands are fixed in 10% neutral-buffered formalin. Whole globes and eyelids are fixed in modified Davidson’s fixative for 24 to 48 hours and then transferred into 70% ethanol. For histopathology assessment, eyes are trimmed, processed, embedded in paraffin, microtomed, stained with H&E and coverslipped. Sagittal ocular section are obtained from 3 different regions. Eyelids, harderian and lacrimal glands are similarly processed and included in the histopathological evaluation. Slides are examined by a veterinary pathologist.

[0093] Example 5. Inhibition of Re tinos chisis by Dorzolamide and Brinzolamide in a Murine RS1-KO Model (Prophetic Example)

[0094] Thirty genotyped male RS1-KO mice (strain C57BL / 6JCya-RsIeml / Cya) at postnatal day 30 (PND30 + / -3 days) undergo an ophthalmic exam for enrollment to ascertain absence of gross ocular abnormalities, optical coherence tomography (OCT), to assess degree 12

[0095] 185416057 1of retinoschisis, and electroretinogram (ERG), to determine baseline a-wave / b-wave amplitudes and ratio. Following this baseline exam, mice are randomized into 3 groups of 10 mice each to receive bilateral treatment with a 5 pL volume of 2% dorzolamide HCL ophthalmic solution, 1% brinzolamide ophthalmic suspension or vehicle instilled topically 3 times per day (TID) is initiated continuing for 28 days. One hour after the final topical treatment, OCT and ERG assessments are repeated. Both eyes of each animal are then enucleated, with one fixed in 10% neutral-buffered formalin for histopathology evaluation, and the other dissected to harvest retina and RPE / choroid tissues separately for determination of drug levels. Tissues slated for drug exposure determination are immediately frozen after dissection and pooled (10 per tissue type) within each group. Tissue levels of drug are analyzed with a qualified LC-MS / MS bioanalytical method.

[0096] Example 6. Treatment of XLRS patients (Prophetic Example)

[0097] Patients with XLRS having an ETDRS BCVA of 65 letters or worse in at least one eye are treated by the placement of an implant releasing lug / day of dorzolamide for 6 months in both eyes. The efficacy of the implant is assessed by measuring decreases in central macular thickness (decrease in retinoschisis) and improvement in BCVA. The treated eyes are evaluated every month for improvement of letters of BCVA and reduction in central macular thickness.

[0098] Example 7. Treatment of Retinoschisis Patients (Prophetic Example)

[0099] Patients with eyes that show retinoschisis by OCT and ETDRS BCVA of 65 letters or worse that in the opinion of the investigator is due to a genetic retinal degeneration such as XLRS, Retinitis pigmentosa, etc are treated by the placement of an implant releasing lug / day of dorzolamide for 6 months into the eye. The treated eyes are evaluated every month for improvement of letters of BCVA and reduction in central macular thickness.

[0100] Example 8. Clinical study (Prophetic Example)

[0101] A group of 30 patients with XLRS having an ETDRS BCVA of 65 letters or worse in at least one eye are enrolled and randomized 1: 1 to treatment by placement of a CAI-releasing implant vs sham. The treated patients are given an implant into the worse eye that releases lug / day of dorzolamide for 6 months. The efficacy of the implant is assessed by measuring decreases in central macular thickness (decrease in retinoschisis) and improvement 13

[0102] 185416057 1in BCVA. The treated eyes are evaluated every month for improvement of letters of BCVA and reduction in central macular thickness.

[0103] Example 9. Clinical study (Prophetic Example)

[0104] A group of 30 patients with XLRS having an ETDRS BCVA of 65 letters or worse in at least one eye are enrolled and randomized 1: 1 to treatment by placement of a CAI-releasing implant vs sham. The treated patients are given an implant into the worse eye that releases lOug / day of dorzolamide for 6 months. The efficacy of the implant is assessed by measuring decreases in central macular thickness (decrease in retinoschisis) and improvement in BCVA. The treated eyes are evaluated even' month for improvement of letters of BCVA and reduction in central macular thickness.

[0105] 14

[0106] 185416057 1

Claims

WHAT IS CLAIMED IS:

1. A method for treating X-linked retinoschisis (XLRS) in a subject, comprising the step of administering an effective amount of a carbonic anhydrase inhibitor (CAI), or a pharmaceutically acceptably salt or prodrug thereof, to the posterior segment of the eye of a subject in need thereof, via intravitreal injection.

2. The method of claim 1, wherein the CAI is selected from the group consisting of dorzolamide, brinzolamide, acetazolamide, methazolamide, ethoxzolamide, MK 0927, sezolamide, Compound 8, Compound 9, Compound 10, and any combination thereof,Compound 10.

3. The method of claim 1 or 2, wherein the CAI is dorzolamide or brinzolamide.

4. The method of any one of claims 1 to 3, wherein the CAI is contained in a biodegradable sustained-release implant, and is released at a rate between 0.1 and 15 pg / day.15185416057 15. The method of any one of claims 1 to 4, wherein the CAI achieves a maximal concentration (Cmax) in the non-pigmented posterior retina between 0.02 and 20 pg / g tissue, or preferably between 0.1 and 10 pg / g tissue6. The method of claim 4 or 5, wherein the implant contains between 0.01 and 2 mg of the CAI.

7. The method of any one of claims 4 to 6, wherein the implant has a size between 3 and 15 mm in length and between 0.05 and 1 mm in diameter8. A method for treating patients with genetically driven retinoschisis in a subject, comprising the step of administering an effective amount of a carbonic anhydrase inhibitor (CAI), or a pharmaceutically acceptably salt or prodrug thereof, to the posterior segment of the eye of a subject in need thereof, via intravitreal inject on.

9. The method of claim 8, wherein the CAI is selected from the group consisting of: dorzolamide, brinzolamide, acetazolamide, methazolamide, ethoxzolamide, MK 0927, sezolamide, Compound 8, Compound 9, Compound 10, and any combination thereof.

10. The method of claim 8 or 9. wherein the CAI is dorzolamide or brinzolamide.

11. The method of any one of claims 8 to 10, wherein the CAI is contained in a biodegradable implant, and is released at a rate between 0.1 and 15 pg / day.

12. The method of any one of claims 8 to 11, wherein the CAI achieves a maximal concentration (Cmax) in the non-pigmented posterior retina between 0.02 and 20 pg / g tissue, or preferably between 0.1 and 10 pg / g tissue.

13. The method of claim 11 or 12, wherein the implant contains between 0.01 and 2 mg of the CAI.16185416057 114. The method of any one of claims 11 to 13, wherein the implant has a size between 3 and 15 mm in length and between 0.05 and 1 mm in diameter.17185416057 1

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