Development of the Port Delivery System with ranibizumab for neovascular age-related macular degeneration

Safety of recent ophthalmic drugs and devices for wet macular degeneration

PURPOSE OF REVIEW

With frequent antivascular endothelial growth factors (VEGF) injections well established as the standard of care in neovascular age-related macular degeneration (nAMD), focus has now shifted towards decreasing treatment burden without compromising safety and efficacy. This review summarizes clinical stage and recently approved drugs and devices for nAMD, with an emphasis paid to safety concerns and their implications for product adoption.

RECENT FINDINGS

Three strategies have emerged to decrease the treatment burden associated with the current standard of care: more durable intravitreal agents, sustained-release modalities and gene therapy. The appearance of biosimilars will further impact drug availability and cost. As patterns of adverse events emerge from clinical trial or postmarketing surveillance data, manufacturers have proactively responded by appointing independent review committees or issuing voluntary recalls. However, the example of one biosimilar approved outside of the USA and European Union demonstrates how early safety concerns, even when addressed by substantive data, can generate lingering uncertainty.

SUMMARY

As the number of promising new treatments in nAMD continues to grow, so too does the amount of data that providers must sift through. The perception of safety surrounding first movers in each new therapeutic area is sure to affect adoption of that modality more broadly.

Beyond VEGF: Targeting Inflammation and Other Pathways for Treatment of Retinal Disease

Neovascular eye diseases include conditions such as retinopathy of prematurity, proliferative diabetic retinopathy, and neovascular age-related macular degeneration. Together, they are a major cause of vision loss and blindness worldwide. The current therapeutic mainstay for these diseases is intravitreal injections of biologics targeting vascular endothelial growth factor (VEGF) signaling. Lack of universal response to these anti-VEGF agents coupled with the challenging delivery method underscore a need for new therapeutic targets and agents. In particular, proteins that mediate both inflammatory and proangiogenic signaling are appealing targets for new therapeutic development. Here, we review agents currently in clinical trials and highlight some promising targets in preclinical and early clinical development, focusing on the redox-regulatory transcriptional activator APE1/Ref-1, the bioactive lipid modulator soluble epoxide hydrolase, the transcription factor RUNX1, and others. Small molecules targeting each of these proteins show promise for blocking neovascularization and inflammation. The affected signaling pathways illustrate the potential of new antiangiogenic strategies for posterior ocular disease. SIGNIFICANCE STATEMENT: Discovery and therapeutic targeting of new angiogenesis mediators is necessary to improve treatment of blinding eye diseases like retinopathy of prematurity, diabetic retinopathy, and neovascular age-related macular degeneration. Novel targets undergoing evaluation and drug discovery work include proteins important for both angiogenesis and inflammation signaling, including APE1/Ref-1, soluble epoxide hydrolase, RUNX1, and others.

Co-delivery of an HIV prophylactic and contraceptive using PGSU as a long-acting multipurpose prevention technology

OBJECTIVES

Poly(glycerol sebacate) urethane (PGSU) elastomers formulated with 4'-ethynyl-2-fluoro-2'-deoxyadenosine (EFdA), levonorgestrel (LNG), or a combination thereof can function as multipurpose prevention technology implants for prophylaxis against HIV and unintended pregnancies. For these public health challenges, long-acting drug delivery technologies may improve patient experience and adherence. Traditional polymers encounter challenges delivering multiple drugs with dissimilar physiochemical properties. PGSU offers an alternative option that successfully delivers hydrophilic EFdA alongside hydrophobic LNG.

METHODS

This article presents the formulation, design, and characterization of PGSU implants, highlighting the impact of API loading, dimensions, and individual- versus combination-loading on release rates.

RESULTS

Co-delivery of hydrophilic EFdA alongside hydrophobic LNG acted as a porogen to accelerate LNG release. Increasing the surface area of LNG-only implants increased LNG release. All EFdA-LNG, EFdA-only, and LNG-only formulated implants demonstrated low burst release and linear release kinetics over 245 or 122 days studied to date.

CONCLUSION

PGSU co-delivers two APIs for HIV prevention and contraception at therapeutically relevant concentrations in vitro from a single bioresorbable, elastomeric implant. A new long-acting polymer technology, PGSU demonstrates linear-release kinetics, dual delivery of APIs with disparate physiochemical properties, and biocompatibility through long-term subcutaneous implantation. PGSU can potentially meet the demands of complex MPT or fixed-dose combination products, where better solutions can serve and empower patients.

Release of ranibizumab using a porous poly(dimethylsiloxane) capsule suppressed laser-induced choroidal neovascularization via the transscleral route

The administration of anti-vascular endothelial growth factor drugs in the posterior eye segment with sustained release through less invasive methods is a challenge in the treatment of age-related macular disease. We developed a flexible capsule device using porous poly(dimethylsiloxane) (PDMS) that was able to release ranibizumab. The porous PDMS sheet was fabricated by salt-leaching of a micro-sectioned PDMS sheet containing salt microparticles. Observation with scanning electron microscopy revealed that the pore densities could be adjusted by the concentration of salt. The in vitro release study showed that the release rate of fluorescein isothiocyanate-tagged albumin could be adjusted based on the pore density of the porous PDMS sheet. Ranibizumab could be released in a sustained-release manner for 16 weeks. The device was implanted on the sclera; its efficacy in terms of the suppression of laser-induced choroidal neovascularization (CNV) in rats was compared with that of monthly intravitreal injections of ranibizumab. At 8 and 18 weeks after implantation, the CNV area was significantly reduced in rats that received the ranibizumab-releasing device compared with those that received the placebo device. However, although monthly intravitreal injections of ranibizumab reduced CNV for 8 weeks, this reduction was not sustained for 18 weeks. In conclusion, we demonstrated a novel controlled-release device using a porous PDMS sheet that could suppress CNV via a less invasive transscleral route versus intravitreal injections. This device may also reduce the occurrence of side effects associated with frequent intravitreal injections.

Ranibizumab port delivery system: a clinical perspective

Age-related macular degeneration (AMD) represents a leading cause of blindness worldwide. Neovascular AMD (nAMD) is a subtype of AMD most frequently treated with intravitreal anti-vascular endothelial growth factor (aVEGF) injections, which has allowed for patients to maintain vision that would have otherwise been lost. However, the need for frequent intravitreal injections for optimal results poses a risk for undertreatment in nAMD patients due to the high treatment burden associated with current aVEGF therapy. Many novel agents and pathways are being explored and targeted for less burdensome treatment options, one of which is the ranibizumab port delivery system (PDS). The PDS is a surgically implanted, refillable device that allows for the sustained release of ranibizumab, a widely used aVEGF agent, into the vitreous cavity. Positive results non-inferior to monthly ranibizumab injections in both phase II and phase III clinical trials allowed for FDA approval of the device with refill intervals of 6 months, which represents the longest approved treatment interval to date for nAMD therapy. This article reviews the need for a durable nAMD treatment option in real-world practice, the clinical trial and extension study data for the PDS, the risk of adverse events and safety profile of the PDS and the potential clinical role of the PDS in answering the real-world needs of nAMD treatment. In addition, other pipeline sustained-treatment modalities are discussed in the context of ongoing clinical trials.

Long-acting ocular drug delivery technologies with clinical precedent

INTRODUCTION

Ocular long-acting injectables and implants (LAIIs) deliver drug at a controlled release rate over weeks to years. A reduced dose frequency eases the treatment burden on patients, minimizes the potential for treatment-related adverse effects, and improves treatment adherence and persistence.

AREAS COVERED

This review provides a comprehensive landscape of ocular LAII drug delivery technologies with clinical precedent, including eight commercial products and 27 clinical programs. Analysis of this landscape, and the specific technologies with the greatest precedent, provides instructive lessons for researchers interested in this space and insights into the direction of the field.

EXPERT OPINION

Further technological advancement is required to create biodegradable LAIIs with extended release durations and LAIIs that are compatible with a broader array of therapeutic modalities. In the future, ocular LAII innovations can be applied to diseases with limited treatment options, prophylactic treatment at earlier stages of disease, and cost-effective treatment of ocular diseases in global health settings.