Introduction to Sustained Retinal Drug Delivery

Managing chronic retinal vascular diseases like neovascular age-related macular degeneration (nAMD) and diabetic macular edema (DME) requires consistent anti-VEGF therapy. However, the heavy burden of monthly or bimonthly intravitreal injections often leads to undertreatment in real-world settings. The Port Delivery System Ranibizumab (PDS) addresses this challenge by providing a refillable, indwelling ocular implant that continuously releases medication over several months. Consequently, this technology significantly reduces the frequency of clinic visits and invasive procedures for patients.

Overcoming Challenges and Enhancing Safety

Following a voluntary recall in late 2022 due to septum dislodgement concerns, researchers and engineers implemented critical structural updates. Specifically, manufacturing refinements have doubled the bond strength between the septum and the overmold. Additionally, a new, lightly lubricated refill needle reduces insertion force by over 50%. These technical improvements, which received regulatory clearance in late 2024 and early 2025, have successfully mitigated the risk of device-related complications. Surgeons now utilize these updated components to ensure long-term durability and patient safety.

Long-Term Outcomes for Port Delivery System Ranibizumab

Recent data from the Portal extension study provides reassuring evidence regarding the long-term efficacy of the Port Delivery System Ranibizumab. Specifically, five-to-seven-year results demonstrate that approximately 95% of patients do not require supplemental injections between their six-month refill-exchange procedures. Furthermore, nearly half of the participants maintained a visual acuity of 20/40 or better throughout the follow-up period. While the risk of endophthalmitis remains higher than with traditional injections, meticulous surgical training and aseptic techniques in the operating room continue to improve clinical outcomes.

Clinical Implications for Physicians

The reintroduction of the PDS platform offers a vital alternative for patients who respond well to anti-VEGF therapy but struggle with injection frequency. Physicians should identify appropriate candidates who have previously responded to at least two intravitreal injections. Moreover, surgeons must emphasize the importance of monitoring for conjunctival health, as proper wound closure is essential to prevent erosions. Ultimately, the PDS represents a shift toward more sustainable management of vision-threatening retinal diseases.

Frequently Asked Questions

How often does the Port Delivery System Ranibizumab require refilling?

The system typically requires a refill-exchange procedure every 24 weeks, or approximately every six months. Clinical trials show that the vast majority of patients maintain stable vision and anatomy on this fixed interval.

What are the primary risks associated with the PDS implant?

The most significant risks include endophthalmitis, conjunctival erosion, and vitreous hemorrhage. However, recent refinements in surgical technique and device manufacturing have focused on minimizing these adverse events.

Disclaimer: This content is for informational and educational purposes only and does not constitute medical advice. It is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified healthcare provider with any questions you may have regarding a medical condition. Refer to the latest local and national guidelines for clinical practice.

References

Samman M et al. An update on the port delivery system with ranibizumab for retinal diseases. Expert Opin Drug Deliv. 2026 Apr 06. doi: 10.1080/17425247.2026.2652029. PMID: 41937714.

Pieramici DJ et al. Structural updates to the implant and refill needle of the port delivery platform. Transl Vis Sci Technol. 2025;14(4):8. doi: 10.1167/tvst.14.4.8.

Genentech Inc. Important Safety Information: Update on Susvimo (ranibizumab injection) 100 mg/mL. March 2025.