New guidelines supporting best practices for suprachoroidal space (SCS) injections have been published in RETINA, The Journal of Retinal and Vitreous Diseases.
Let’s start with SCS.
First: SCS is the area located between the sclera and the choroid that is one available route for providing minimally-invasive medication delivery.
Its role: Maintaining intraocular pressure via uveoscleral outflow (an alternative drainage route for the aqueous humor) and serving as a natural flow path from the front to the back of the eye.
- And potential: To expand and contract in response to the presence of fluid.
Now injections.
While not the most common form of retinal therapeutic delivery (which would be intravitreal injections), subretinal injections have “been used for targeted delivery of retinal gene therapy and stem cell-derived retinal pigment epithelium,” according to investigators.
However: Such administration requires pars plana vitrectomy for retinopathy—and the resulting delivery is restricted to a limited area either at or around the delivery point.
This variable delivery has been noted to pose challenges.
And SCS injections?
SCS injections have the potential to provide targeted delivery of high levels of injections directly to affected chorioretinal tissues—see here for an example of how they work.
The advantages of this approach over other forms of administration include:
- Higher drug concentrations
- Increased bioavailability
- Prolonged duration of action
- Minimized risk for corticosteroid-related adverse events (AEs)
- Example: cataracts and intraocular pressure (IOP) elevation via compartmentalization
What’s the latest technology for this?
Clearside Biomedical’s SCS Microinjector is the first and only FDA-approved treatment designed to directly deliver a therapeutic into the SCS and provide a targeted delivery to the chorioretinal tissues.
The intended result: Improved efficacy and compartmentalization of medication, leading to a reduction or elimination of toxic effects on non-disease cells.
- Plus: The microinjector rapidly disperses medicine into the back of the eye—enabling a longer-lasting effect
Back up … tell me about this therapeutic.
Clearside’s XIPERE (triamcinolone acetonide injectable suspension) 40 mg/mL is the first FDA-approved therapeutic for delivery into the SCS via the SCS Microinjector.
Formulated as a proprietary suspension of a corticosteroid (triamcinolone acetonide), it’s indicated for the treatment of uveitic macular edema. See its full prescribing information here.
Bonus: See here and here for our coverage on CLS–AX (axitinib injectable suspension), the company’s other investigational CSC therapeutic, currently undergoing clinical trials.
Alrighty Now talk about these guidelines.
The publication—titled Suprachoroidal Space Injection Technique: Expert Panel Guidance—was co-authored by 16 practicing retinal physicians and based on current published evidence and clinical experience on SCS.
Their goal: To develop and define consensus points and key clinical considerations for establishing guidelines for proper in-office SCS injection use.
So how did they identify the key points?
First by establishing the following categories as the main topic areas of discussion:
- Rationale for SCS injection
- Patient considerations and expectation setting
- Pre/peri-injection management
- Injection technique
- Post-injection management
- Follow-up
And from there?
The retinal physicians developed their initial consensus points and then reviewed and discussed each category based on the current clinical evidence and data on SCS injection use.
The result: Establishment of current, evidence-based guidelines for in-office use of SCS injections.
Give me the final guidelines.
Here you go (hint: click the bolded title of each to read more on the guidelines themselves as well as the panel’s commentary regarding each section):
- General patient considerations
- Decision to perform based on individual patient and clinical evidence
- Physicians should establish patient expectations, particularly for those who previously underwent intravitreal injection
- Guidelines for pre- and per-injection management
- Clinical (office-based) setting
- Bilateral injections
- Same-day is appropriate, with both eyes treated as separate procedures
- Gloves, draping, talking, and mask use
- Not necessary but should be used in line with office protocols
- Patient positioning
- Should be in a relaxed position with head support
- Local anesthetic use
- Based on physician preference; may include topical drops, lidocaine-soaked pledgets, gel, or subconjunctival anesthetic
- Pupil dilation
- Pre-SCS injection pupil dilation not essential but can be dependent on physician preference for supporting post-injection monitoring
- Globe softening
- Via gentle massaging or application with soft pressure to the globe prior to SCS injection; not required but up to physician
- Sterile speculum use
- Recommended during SCS injection due to longer duration of injection vs intravitreal procedures
- Initial needle length and injection site selection
- Selected to optimize visualization and surgical approach for minimization of need for needle switching
- Povidone-iodine antiseptic use
- Local antiseptic use highly recommended prior to SCS injection to minimize infection risk
- Guidelines for injection procedure and technique
- SCS microinjection preparation and technique
- Specific injection performance procedure recommended , from administration of vial to preparation and proper technique based on physician’s judgment and experience
- SCS microinjection preparation and technique
- Guidelines for quadrant or needle switching
- Specific steps are advised to limit the need for needle switching
- Guidelines for postinjection management and follow-up
- Includes evaluation of IOP and general ocular function in accordance with standard office protocols and the product’s PI