Travoprost Intracameral Implant: Uses, Dosage, Precautions, Side Effects, and Pharmacological Aspects

Overview:

Travoprost intracameral implant is an innovative solution for managing intraocular pressure, primarily in conditions like glaucoma (a progressive eye condition characterized by increased intraocular (inside the eye) pressure, potentially leading to optic nerve damage and vision loss). Administered directly into the eye's front chamber, the implant releases Travoprost, a prostaglandin analog, through a controlled delivery system.

Anchored precisely in the iridocorneal angle (a junction between the iris and the cornea in the eye), it aims to reduce intraocular pressure by enhancing aqueous humor drainage. Personalized dosing considerations and awareness of potential drug interactions are essential for optimizing therapeutic outcomes, marking this implant as a promising advancement in ocular care. A significant stride in ocular therapeutics was marked by the US FDA's (United States Food and Drug Administration) approval for the Travoprost intracameral implant on December 14, 2023.

Drug Group:

Travoprost intracameral implant belongs to the drug class of prostaglandin analogs. Travoprost is a synthetic prostaglandin F2 alpha analog. Prostaglandin analogs are medications that lower intraocular pressure in the eyes and are commonly used to treat glaucoma, a set of ocular conditions that may harm the optic nerve and cause vision loss. These medications enhance the outflow of aqueous humor, the fluid within the eye, consequently lowering intraocular pressure.

Available Doses and Dosage Forms:

The Travoprost intracameral implant comprises a Travoprost delivery system with a pre-loaded implant in a sterile, single-dose inserter. Administered intracamerally (into the eye's front chamber, the space between the cornea and the iris), it is anchored at the iridocorneal angle through a precise corneal incision. Single-dose inserter pre-loaded with an intracameral implant containing 75 mcg (microgram) of Travoprost.

Indications

Travoprost intracameral implant is prescribed to lower intraocular pressure (IOP) in individuals diagnosed with open-angle glaucoma (OAG) or ocular hypertension (OHT); both conditions are characterized by elevated intraocular pressure, with OAG involving optic nerve damage and visual field loss.

For Patients:

What Is Open-Angle Glaucoma?

Open-angle glaucoma is a chronic eye condition characterized by increased intraocular pressure (IOP) due to the gradual blockage of the eye's drainage channels. Unlike closed-angle glaucoma, which involves a sudden and often painful blockage of drainage, open-angle glaucoma progresses gradually and typically lacks discernible symptoms during its initial phases. Over time, increased intraocular pressure (IOP) can cause damage to the optic nerve, leading to a loss of vision. Routine eye examinations are pivotal in promptly identifying and managing open-angle glaucoma.

How Does Travoprost Intracameral Implant Work?

Travoprost functions as a prostaglandin analog, enhancing the outflow of aqueous humor (the fluid within the eye) to lower intraocular pressure. It does this by binding to specific receptors in the eye called prostaglandin receptors, which are mainly found in the eye's ciliary body. The production of aqueous humor is attributed to the ciliary body. The exact mechanism of how Travoprost intracameral implants work would depend on the specific formulation and design of the implant. Generally, intracameral implants are devices placed directly into the anterior chamber of the eye to deliver medication gradually and maintain controlled release over an extended period.

What Is the Dosage of Travoprost Intracameral Implant?

Travoprost intracameral implant, delivered through a single-dose inserter, features a pre-loaded implant containing 75 mcg of Travoprost, administered intracamerally and anchored at the iridocorneal angle via a precise corneal incision.

What Are the Things to Inform the Doctor Before Inserting a Travoprost Intracameral Implant?

Things to inform the doctor before Travoprost intracameral implant insertion:

• Allergies: Report known allergies, especially to medications or substances.

• Medical History: Provide details on eye conditions, surgeries, infections, and other health issues.

• Medications: Inform about current prescriptions and over-the-counter (OTC) drugs, including eye drops and supplements.

• Pregnancy or Breastfeeding: Discuss status, as it may impact the decision to use the implant.

• Previous Treatments: Share information about past eye treatments or surgeries, particularly for glaucoma.

• Infections: Notify the doctor of recent eye infections, inflammation, or injuries.

• Contact Lenses: Discuss contact lens use before and after the procedure.

• Other Medical Conditions: Mention relevant health conditions, such as diabetes (high sugar in the blood) or autoimmune disorders (disorders in which the immune system attacks its cells or tissues).

What Are the Side Effects of the Travoprost Intracameral Implant?

The most commonly reported eye-related side effects (between two percent and six percent) of the Travoprost intracameral implant in clinical trials were:

• Increased Intraocular Pressure: This refers to a rise in pressure inside the eye, which may affect vision.

• Iritis: Iritis is inflammation of the colored part of the eye (iris) and can cause pain and sensitivity to light.

• Dry eye: Dry eye occurs when there is insufficient moisture on the eye's surface, leading to discomfort.

• Visual Field Defects: This refers to abnormalities or limitations in the visual field, affecting the ability to see certain areas.

• Eye Pain: Patients may experience discomfort or pain in the eyes.

• Ocular Hyperemia: Also known as red eyes, involves increased blood flow to the eye's surface, causing redness.

• Reduced Visual Acuity: This term indicates a decrease in the clarity of vision.

Side effects reported in less than two percent of patients were:

• Conjunctival Hemorrhage: Bleeding in the conjunctiva, the delicate tissue covering the white part of the eye.

• Photophobia: Sensitivity to light.

• Punctate Keratitis: Small areas of inflammation on the cornea, the eye's clear front surface.

• Blepharitis: Inflammation of the eyelids.

• Eye Irritation: Discomfort or itching in the eyes.

• Corneal Abrasion: A scratch or cut on the surface of the cornea.

• Device Dislocation: Movement or shifting of the implanted device.

• Vitreous Detachment: Separation of the jelly-like substance (vitreous) in the eye from the retina.

• Foreign body sensation in eyes: Feeling as if there is something foreign or irritating in the eyes.

Dietary Considerations:

Nothing specific. Maintenance of a balanced diet is crucial.

Overdose:

Overdose with a Travoprost intracameral implant is generally unlikely, as the implant is designed to release a controlled and sustained amount of medication into the eye over an extended period. The device is pre-loaded with a specific dosage of Travoprost and inserted directly into the eye during a medical procedure.

Storage:

Travoprost intracameral implant, identified by NDC 25357-100-01, comes in a sterile, pre-loaded inserter sealed within a blister tray with a Tyvek lid. Each implant has a unique serial number indicated on the tray lid. The tray and an oxygen scavenger packet are enclosed in a transparent plastic pouch within a unit carton, featuring tamper-evident seals at both ends.

For storage, keep the Travoprost intracameral implant between two and 25 degrees Celsius (36 and 77 degrees Fahrenheit) and avoid freezing.

For Doctors

Description:

Travoprost, a prostaglandin analog with a chemical structure described as 5-heptanoic acid, has a molecular formula of C26H35F3O6 and a molecular weight of 500.55 g/mol (gram per mole). It appears as a clear, colorless, slightly yellow oil highly soluble in acetonitrile, methanol, octanol, and chloroform but practically insoluble in water.

Dose: Travoprost intracameral implant is a sterile intracameral implant containing 75 mcg of Travoprost, consisting of a titanium reservoir with a membrane for sustained release. Pre-loaded in a sterile single-dose inserter, it facilitates direct insertion through the trabecular meshwork into the sclera.

How Is Travoprost Intracameral Implant Inserted in the Eye?

The implant comes pre-loaded with a precise amount of Travoprost and is inserted directly into the eye as part of a medical procedure.

Procedure Guidelines:

• Use sterile gloves and drape to ensure aseptic conditions during the Travoprost intracameral implant insertion.

• Anesthetize the eye using general, retrobulbar, peribulbar, or topical anesthesia as per standard operating room procedures.

• Perform the Travoprost intracameral implant insertion procedure under magnification for clear visualization of the anterior chamber angle and structures with the patient's head stabilized. Avoid pupil dilation before the procedure.

• Consider injecting an intracameral miotic (injecting pupil-constricting medication into the eye) to deepen the angle before inserting the implant.

• Recommend performing the implant surgery from the temporal side, using a clear corneal incision. Insert the implant through the angle into the sclera on the nasal side.

• Unpack the Travoprost intracameral implant, ensuring the packaging is undamaged. Handle the implant and inserter in a sterile field. Do not use it if the packaging is damaged.

• Prepare for gonioscopy (an eye exam to assess the drainage angle), position the patient's head, and adjust the scope for a clear view of the angle structures.

• Apply a small amount of viscoelastic on the cornea and position the gonioprism for clear visualization of the trabecular meshwork.

• Inspect the angle with a gonioprism to ensure a good view of the nasal implant location.

• Hold the inserter with the index finger on the implant release button.

• Inspect the inserter tip under magnification to confirm the presence of the Travoprost intracameral implant.

• Use the surgeon's preferred instrument to create a clear corneal incision of approximately 2.4 mm (millimeter) at the temporal limbus.

• Add cohesive viscoelastic to the anterior chamber for visualization and to avoid overinflation.

Implantation Steps:

• Remove the safety clip and ensure the release button is forward.

• Slide the inserter tip side to side in the incision to enter the anterior chamber.

• Advance to the pupillary margin, ensuring sufficient viscoelastic (a material with fluid and solid-like properties).

• Approach the trabecular meshwork and press the implant through, anchoring it securely in the sclera.

• Release the implant from the inserter, anchoring it into scleral tissue.

• Apply slight pressure to ensure proper anchoring. If necessary, reposition the implant and avoid re-implanting at the same location.

• Withdraw the inserter.

Confirmation of the Implant:

• Confirm the Travoprost intracameral implant position in the trabecular meshwork through a high-magnification examination.

• Confirm proper positioning with the proximal end in the anterior chamber and the anchor embedded in the sclera.

• Note contact with the iris, and irrigate and aspirate the anterior chamber to remove viscoelastic.

• Inflate the anterior chamber with saline to achieve physiological pressure.

What Are the Pharmacological Aspects of the Travoprost Intracameral Implant?

Pharmacodynamics:

Travoprost is a prostaglandin analog employed for treating glaucoma and ocular hypertension. The potential intracameral implant form of Travoprost suggests a sustained-release system. Intracameral implants are formulated to administer the medication directly to the eye's anterior chamber, ensuring a prolonged and controlled drug release.

This method can enhance patient compliance and reduce the need for frequent topical administrations. The sustained release of Travoprost from an intracameral implant would likely provide a prolonged therapeutic effect, helping maintain consistent intraocular pressure control over an extended period. This can benefit individuals who may face challenges in administering standard eye drops regularly.

Mechanism:

• Travoprost free acid, a prostaglandin analog, acts as a selective FP prostanoid receptor agonist, thought to lower intraocular pressure (IOP) by enhancing uveoscleral outflow. The precise mechanism of action remains unclear.

Pharmacokinetics:

• Metabolism: Travoprost, functioning as an isopropyl ester prodrug, undergoes hydrolysis by esterases in the cornea and intraocular tissues. This enzymatic process converts it into its biologically active free acid form. Systemically, the free acid undergoes metabolic pathways, including beta-oxidation of the alpha (Carboxylic acid) chain, resulting in the formation of 1,2-dinor and 1,2,3,4-tetranor analogs. Additionally, oxidation of the 15-hydroxyl moiety and reduction of the 13,14 double bond contribute to forming inactive metabolites.

• Absorption: Travoprost is absorbed through intraocular tissues, particularly the cornea, following administration. As an Isopropyl ester prodrug, it undergoes hydrolysis by corneal esterases to its active free acid form.

• Excretion: Metabolites of the Travoprost-free acid are excreted systemically. The information does not specify the excretion pathways and organs involved in the elimination process.

Non-Clinical Toxicity:

Carcinogenesis:

Extended two-year studies in mice and rats, administered subcutaneously at 10, 30, or 100 mcg/kg/day, revealed no signs of carcinogenic potential. However, male rats at 100 mcg/kg/day were treated for only 82 weeks, and the mouse study did not reach the maximum tolerated dose (MTD). The high dose (100 mcg/kg) was over 500 times the maximum human ocular dose (MHOD) based on body surface area (BSA).

Mutagenesis:

Travoprost exhibited no mutagenic effects in the Ames test, mouse micronucleus test, or rat chromosome aberration assay. Although a slight rise in mutant frequency was noted in one of two mouse lymphoma assays in the presence of rat S-9 activation enzymes, the overall assessment concluded the absence of mutagenic potential.

Impairment of Fertility:

Subcutaneous doses of up to 10 mcg/kg/day (116 times the MHOD based on BSA) did not impact mating or fertility indices in male or female rats. However, at 10 mcg/kg/day, a reduction in the mean number of corpora lutea and increased post-implantation losses were noted. These effects were absent at three mcg/kg/day (34.5 times the MHOD based on BSA).

Clinical Studies:

Travoprost intracameral implant, a treatment for eye conditions, was tested in two studies involving patients with certain eye problems. It was compared to using Timolol (a beta-blocker medication) eye drops twice a day. In the first three months, the Travoprost intracameral implant showed a good decrease in eye pressure (IOP) in the study eye. It was as effective as the Timolol eye drops during this period. However, after the initial three months, the Travoprost intracameral implant did not continue to show the same level of effectiveness compared to Timolol eye drops.

What Are the Contraindications of Travoprost Intracameral Implants?

The contraindications of the Travoprost intracameral implant:

• Ocular or Periocular Infections: Travoprost intracameral implant is not recommended for patients with active or suspected ocular or periocular infections.

• Corneal Endothelial Dystrophy: Travoprost intracameral implant is contraindicated in individuals with corneal endothelial cell dystrophy, such as Fuch’s dystrophy or corneal guttata, a progressive eye condition characterized by the gradual loss of corneal endothelial cells, leading to visual impairment.

• Prior Corneal Transplantation: Travoprost intracameral implant is contraindicated in patients with a history of corneal transplantation or endothelial cell transplants, including Descemet’s stripping automated endothelial keratoplasty (DSAEK).

• Hypersensitivity: Travoprost intracameral implant is contraindicated in individuals with hypersensitivity to Travoprost or other product components.

Warnings and Precautions:

The warnings and precautions are as follows:

• Caution in Angle Abnormalities: It is necessary to exercise caution when using a Travoprost intracameral implant in patients with narrow iridocorneal angles (Shaffer grade less than three) or other angle abnormalities (peripheral anterior synechia, rubeosis iridis) that may hinder proper Travoprost intracameral implant placement.

• Device Dislocation: Monitor patients regularly for Travoprost intracameral implant dislocation, observed in clinical trials; surgical removal is recommended if dislocated.

• Macular Edema: Use Travoprost intracameral implant cautiously in aphakic refers to the absence of the natural crystalline lens in the eye, typically after cataract surgery or pseudophakic patients (having an artificial intraocular lens implanted in place of the natural lens after cataract surgery) with a torn posterior lens capsule or those with known risk factors for macular edema (swelling or fluid accumulation in the macula, the central part of the retina), as it has been reported during ophthalmic Travoprost treatment.

• Intraocular Inflammation: Exercise caution with Travoprost intracameral implant in patients with active intraocular inflammation (uveitis), as prostaglandin analogs, including Travoprost intracameral implant, may exacerbate inflammation.

• Pigmentation Changes: Expect increased pigmentation in pigmented tissues during Travoprost administration; iris color changes may be permanent after discontinuation. Regular examinations are advised for patients with noticeably increased iris pigmentation.

• Endophthalmitis Risk: Adhere to proper aseptic technique during Travoprost intracameral implant administration to minimize the risk of endophthalmitis (severe inflammation of the inner tissues of the eye). Patients should be monitored post-administration.

• MRI Conditional: Travoprost intracameral implant is MRI (magnetic resonance imaging) conditional; patients should inform healthcare providers about the implant before undergoing magnetic resonance imaging scans. Follow specific conditions for safe scanning to prevent potential injuries.

Specific Considerations:

Pregnancy Risk with Travoprost Intracameral Implant:

Insufficient studies on Travoprost intracameral implants in pregnant women and Travoprost in animals showed fetal risks. Administer Travoprost intracameral implant during pregnancy only if the benefits outweigh the potential fetal risks.

Data Highlights:

• In rats (10 mcg/kg), Travoprost caused teratogenic effects; fetal NOAEL (no observed adverse effect level) was 3 mcg/kg.

• Travoprost led to post-implantation losses in mice (more than 0.3 mcg/kg); fetal NOAEL was 0.3 mcg/kg, and maternal NOAEL was 1 mcg/kg.

• Rats (more than or equal to 0.12 mcg/kg/day) experienced increased post-natal mortality and decreased neonatal body weight.

Lactation:

There is no available data on the effects of Travoprost on breastfed children or milk production. The presence of Travoprost in human milk following ophthalmic administration is unknown. Consideration of the developmental and health benefits of breastfeeding is advised, weighing against the mother's clinical need for a Travoprost intracameral implant and potential adverse effects on the breastfed child.

Pediatric Use:

The safety and effectiveness of Travoprost intracameral implants have not been established in pediatric patients.

Geriatric Use:

There were no discernible variations in safety or efficacy between elderly individuals and other adult patients.