In this episode of Evidence Based Retina, Rishi P. Singh, MD, FASRS, chats with Dante Pieramici, MD, FASRS, a retina specialist at California Retina Consultants, and discusses recent advances and best practices for the Port Delivery System.
The Port Delivery System
The Port Delivery System (PDS; SUSVIMO, Genentech) is approved for three indications: diabetic retinopathy, diabetic macular edema (DME), and neovascular age-related macular degeneration (nAMD).
The long-term goal of PDS is not only to reduce the burden of frequent injections but also to improve outcomes by maintaining stable vision and anatomy, which often decline with real-world, less frequent injection schedules.
Data on the PDS
ARCHWAY and PORTAL trials
Five- to 7-year data from patients in the ARCHWAY who enrolled in the PORTAL trials for neovascular AMD show that vision and anatomy remain very stable in patients who received PDS, without an increase in new complications.1
The risk of endophthalmitis has been reduced and is now approaching a rate of 1.1%. This lower rate is attributed to modifications in the surgical procedure, specifically being meticulous about opening and closing the conjunctiva and being precise with the scleral incision.
This 1.1% cumulative per-injection rate over 3 to 5 years is similar to what would be expected if patients were given an individual injection every other month.1
To learn more about the findings from the PORTAL study, check out the story Genentech reports 5-year results on SUSVIMO for wet AMD!
PAGODA study
Four-year extension data from the PAGODA trial for DME shows the PDS is functioning well, with refills every 6 months. Fewer than 5% of patients needed supplemental injections between refills. Patients maintained excellent visual improvement (seven or eight letters) and good anatomy, with improvements in their Diabetic Retinopathy Severity Scale (DRSS) score.2
Clinical concerns addressed by the PDS
- Macular Atrophy: The PDS may reduce the incidence and progression of atrophy. The low, steady rate of anti-VEGF delivery, rather than the pulsatile high-dose injections, may be a better way to deliver the drug and reduce atrophy.3
- Anatomical and Visual Fluctuation: The constant, steady-state suppression of VEGF by the PDS can reduce the anatomical and visual acuity fluctuations seen with pulsatile, interval injections, especially when appointments are missed.1
Surgical pearls for PDS implantation
- Careful dissection of the conjunctiva and Tenon's capsule is essential. The conjunctiva and Tenon's capsule should fully cover the implant. The conjunctiva must be positioned over the cornea ("hooding") to accommodate natural tissue retraction and prevent exposure of the implant.
- The scleral incision should not be more than 3.5mm (ideally 3.4mm) to ensure a tight fit and prevent leakage. If the wound is too large, it should be closed with a non-absorbable suture, such as nylon, to reduce the wound size to less than 3.5mm to prevent device dislodgement or leakage.
PDS refill procedure pearls
- Refills take longer than a standard intravitreal injection and should not be scheduled during a busy clinic day.
- The doctor should position themselves on the side opposite the patient to view the port. The needle must be inserted at a very perpendicular angle. A sterile Q-tip should be used to stabilize the eye during the insertion process and to hold the implant in place when the needle is withdrawn.
- Illumination and magnification are useful, since locating the septum is more challenging than during a standard intravitreal injection. Retro-illumination with a bright light directed into the pupil can help visualize the device's septum.
Future agents in PDS
The use of a more durable agent, such as a faricimab, in PDS, is being investigated to potentially extend refill intervals to every 9 to 12 months.4 This change could lessen the burden on patients, their families, and physicians by reducing the frequency of necessary clinic visits.
