The Port Delivery System (PDS) is an intra-scleral sustained drug release device developed for anti-VEGF therapy for neovascular age-related macular degeneration (nAMD). The product name is Susvimo (Genentech/Roche).
The majority of nAMD patients require repeated intravitreal anti-VEGF injections. According to a survey by the American Society of Retina Specialists (ASRS), 75.2% of nAMD patients wish to reduce treatment burden, and reducing the frequency of clinic visits and injections has been an important issue for improving patient quality of life.
PDS is a device designed to significantly extend injection intervals through continuous, passive release of ranibizumab. It was approved by the FDA in October 2021. In 2022, it was recalled from the market due to a risk of septum (self-sealing valve) detachment, but returned to the market in 2024 after device improvements.
Patients with nAMD who have responded to two or more anti-VEGF treatments and have stable disease activity are eligible. It is particularly beneficial for patients with a high burden of frequent intravitreal injections or those with injection phobia.
The symptoms of nAMD itself targeted by PDS are as follows.
Device-related symptoms that may occur after PDS implantation include the following.
Findings of device-related complications that may be observed after PDS implantation are shown below.
It is thought to be caused by the procedure during device implantation or vitreous hemorrhage. A mean decrease of 4 letters has been reported at 1 month postoperatively, but shows a trend toward recovery by the following month. With improvements in implantation technique, the incidence of vitreous hemorrhage has been reduced to 5–10%.
The indications for PDS are nAMD patients who meet the following criteria.
The classification of contraindications and relative contraindications is shown in the table below.
| Category | Details |
|---|---|
| Absolute contraindication | Active intraocular infection/inflammation |
| Absolute contraindication | Hypersensitivity to ranibizumab |
| Relative contraindication | Conjunctival scarring |
| Relative contraindications | Systemic inflammatory diseases (RA, SLE, etc.) |
The following preoperative evaluations are necessary to determine the indication for PDS.
PDS consists of four components.
Main body / Release element
Titanium reservoir body: A small container that stores ranibizumab 100 mg/mL. It is permanently placed in the sclera (superotemporal quadrant).
Release control element: A porous membrane located on the front of the reservoir. It controls the passive diffusion rate of the drug.
Sealing and Fixation Components
Septum: A self-sealing silicone valve. It is the site where a 34G cannula is inserted for refilling. Cause of the 2022 recall (now improved).
Flange: A wing-like structure for fixing the device to the sclera. Used for suture fixation.
The surgery is performed in 8 steps.
| Step | Description |
|---|---|
| ① Conjunctival incision | Incision of the superotemporal conjunctiva and Tenon’s capsule |
| ② Scleral incision | Creation of a 3.5 mm scleral incision |
| ③ Device insertion | Insertion of the reservoir into the vitreous cavity |
| ④ Flange fixation | Fix the device to the sclera with sutures |
| ⑤ Initial fill confirmation | Confirm that it is prefilled with ranibizumab 100 mg/mL |
| ⑥ Diode laser | Laser photocoagulation to prevent retinal tears |
| ⑦ Conjunctival closure | Suture to completely cover the device |
| ⑧ Postoperative confirmation | Check intraocular pressure, perfusion, and device position |
Regular refill exchanges after implantation are performed on an outpatient basis.
Monthly intravitreal injection
Dosing interval: Every month (or PRN/T&E regimen)
Clinic visits: May require 12 or more injection visits per year.
Patient burden: Significant injection fear and visit burden, which may lead to reduced treatment continuation rates.
PDS (Susvimo)
Dosing interval: Refill-exchange every 24 weeks (about 6 months)
Clinic visits: Typically 2 refill-exchange visits per year.
Patient satisfaction: In the Archway trial, 93% of patients reported preferring PDS treatment.
Refill-exchange is performed as an outpatient procedure under local anesthesia. Topical anesthesia and subconjunctival anesthesia are used, and a 34G fine cannula is employed to minimize invasiveness. Mild postoperative discomfort may occur but usually resolves quickly.
Drug release from PDS is based on the principle of passive diffusion.
The release rate of ranibizumab is controlled by the pore size and material of the release control element (porous membrane). The high-concentration drug at 100 mg/mL in the reservoir is continuously released, driven by the concentration gradient with the vitreous cavity. This mechanism allows the intravitreal drug concentration to be maintained within the therapeutic range equivalent to monthly injections.
The titanium body is highly biocompatible and designed for semi-permanent implantation. The device body does not need to be replaced; only refills are required for long-term continuation of treatment.
The key evidence demonstrating the efficacy of PDS comes from the Archway trial.
In the Archway trial (n=418), the ranibizumab 100 mg/mL PDS with refill exchange every 24 weeks achieved non-inferiority to monthly intravitreal injections of ranibizumab 0.5 mg. During the observation period, 98.4% of patients did not require rescue treatment (additional intravitreal injections). Additionally, in a post-trial questionnaire, 93% of patients preferred treatment with PDS (Holekamp NM, et al. Ophthalmology. 2022 [PMID: 34597713]).
In an analysis extended to 2 years (4 refill exchange intervals), PDS Q24W maintained non-inferiority to monthly ranibizumab injections, with approximately 95% of patients not requiring additional treatment during each 24-week interval (Regillo C, et al. Ophthalmology. 2023 [PMID: 36870451]).
Currently, phase 3 trial data on expanding indications beyond nAMD have been reported.
Regarding vitreous hemorrhage, which was a challenge in early clinical use, the introduction of intraoperative diode laser has been reported to reduce the incidence from approximately 50% before implantation to 5–10%. Management algorithms for major intraocular complications such as endophthalmitis, conjunctival erosion, and vitreous hemorrhage are also being systematized (Awh CC, et al. Ophthalmol Retina. 2022 [PMID: 35589078]). The voluntary recall in October 2022 due to a septum defect significantly impacted the future management strategies of patients receiving long-term treatment, but the device returned to the market after improvements (Sharma A, et al. Int J Retina Vitreous. 2023 [PMID: 36717931]).
As of March 2026, Susvimo (PDS) has received FDA approval in the US, but its regulatory status in Japan should be confirmed with the treating physician or a specialized medical institution. In Japan, unapproved drugs or medical devices generally cannot be used in routine clinical practice.
Holekamp NM, Campochiaro PA, Chang MA, et al. Archway Randomized Phase 3 Trial of the Port Delivery System with Ranibizumab for Neovascular Age-Related Macular Degeneration. Ophthalmology. 2022;129(3):295-307. PMID: 34597713. https://pubmed.ncbi.nlm.nih.gov/34597713/
Regillo C, Berger B, Brooks L, et al. Archway Phase 3 Trial of the Port Delivery System with Ranibizumab for Neovascular Age-Related Macular Degeneration 2-Year Results. Ophthalmology. 2023;130(7):735-747. PMID: 36870451. https://pubmed.ncbi.nlm.nih.gov/36870451/
Campochiaro PA, Marcus DM, Awh CC, et al. The Port Delivery System with Ranibizumab for Neovascular Age-Related Macular Degeneration: Results from the Randomized Phase 2 Ladder Clinical Trial. Ophthalmology. 2019;126(8):1141-1154. PMID: 30946888. https://pubmed.ncbi.nlm.nih.gov/30946888/
Campochiaro PA, Eichenbaum D, Chang MA, et al. Interim Results of the Phase III Portal Extension Trial of the Port Delivery System with Ranibizumab in Neovascular Age-Related Macular Degeneration. Ophthalmol Retina. 2025;9(2):144-155. PMID: 39209113. https://pubmed.ncbi.nlm.nih.gov/39209113/
Khanani AM, Campochiaro PA, Graff JM, et al. Continuous Ranibizumab via Port Delivery System vs Monthly Ranibizumab for Treatment of Diabetic Macular Edema: The Pagoda Randomized Clinical Trial. JAMA Ophthalmol. 2025;143(4):326-335. PMID: 40048197. https://pubmed.ncbi.nlm.nih.gov/40048197/
Awh CC, Barteselli G, Makadia S, et al. Management of Key Ocular Adverse Events in Patients Implanted with the Port Delivery System with Ranibizumab. Ophthalmol Retina. 2022;6(11):1028-1043. PMID: 35589078. https://pubmed.ncbi.nlm.nih.gov/35589078/
Sharma A, Khanani AM, Parachuri N, et al. Port delivery system with ranibizumab (Susvimo) recall - What does it mean to the retina specialists. Int J Retina Vitreous. 2023;9(1):6. PMID: 36717931. https://pubmed.ncbi.nlm.nih.gov/36717931/
