International consortium for innovation and quality: An industry perspective on the nonclinical and early clinical development of intravitreal drugs.

The eye, which is under constant exposure to environmental pathogens, has evolved various anatomic and immunological barriers critical to the protection of tissues lacking regenerative capacity, and the maintenance of a clear optic pathway essential to vision. By bypassing the ocular barriers, intravitreal (IVT) injection has become the mainstay for the delivery of drugs to treat conditions that affect the back of the eye. Both small molecules and biotherapeutics have been successfully administered intravitreally, and several drugs have been approved for the treatment of (wet) age-related macular degeneration and diabetic macular edema. However, IVT injection is an invasive procedure, which requires sufficient technical expertise from the healthcare professional administering the drug. Potential side effects include bleeding, retinal tear, cataracts, infection, uveitis, loss of vision, and increased ocular pressure. Pharmaceutical companies often differ in their drug development plan, including drug administration techniques, collection of ocular tissues and fluids, ophthalmology monitoring, and overall conduct of nonclinical and clinical studies. The present effort, under the aegis of the Innovation & Quality Ophthalmic Working Group, aims at understanding these differences, identifying pros and cons of the various approaches, determining the gaps in knowledge, and suggesting feasible good practices for nonclinical and early clinical IVT drug development.

Nonclinical Toxicology and Biocompatibility Program Supporting Clinical Development and Registration of the Port Delivery System With Ranibizumab for Neovascular Age-Related Macular Degeneration.

The Port Delivery System with ranibizumab (PDS) is an investigational drug delivery system designed to provide continuous intravitreal release of ranibizumab for extended durations. The PDS consists of a permanent, surgically placed, refillable intraocular implant; a customized formulation of ranibizumab; and ancillary devices to support surgery and refill procedures. A toxicology program was conducted to evaluate the ocular toxicology and biocompatibility of the PDS to support its clinical development program and product registrational activities. PDS safety studies included a 6-month chronic toxicology evaluation in minipigs as well as evaluation of nonfunctional surrogate implants (comprised of the same implant materials but without ranibizumab) in rabbits. Biocompatibility of the implant and ancillary devices was evaluated in both in vitro and in vivo studies. Implants and extracts from implants and ancillary devices were nongenotoxic, noncytotoxic, nonsensitizing, and nonirritating. Ocular findings were comparable between implanted and sham-operated eyes, and no systemic toxicity was observed. The results of this nonclinical toxicology program demonstrated that the PDS was biocompatible and that intravitreal delivery of ranibizumab via the PDS did not introduce any new toxicology-related safety concerns relative to intravitreal injections, supporting ongoing PDS clinical development and product registrational evaluation.

EVALUATION OF SURGICAL FACTORS AFFECTING VITREOUS HEMORRHAGE FOLLOWING PORT DELIVERY SYSTEM WITH RANIBIZUMAB IMPLANT INSERTION IN A MINIPIG MODEL.

PURPOSE: To develop an animal model of vitreous hemorrhage (VH) to explore the impact of surgical parameters on VH associated with insertion of the Port Delivery System with ranibizumab (PDS) implant. METHODS: Ninety eyes from 45 treatment-naive male Yucatan minipigs received PDS implant insertion or a sham procedure. The effect of prophylactic pars plana hemostasis, scleral incision length, scleral cauterization, surgical blade type/size, and viscoelastic usage on postsurgical VH was investigated. RESULTS: Postsurgical VH was detected in 60.0% (54/90) of implanted eyes. A systematic effect on VH was only detected for pars plana hemostasis before the pars plana incision. The percentage of eyes with VH was 96.6% (28/29) among eyes that did not receive prophylactic pars plana hemostasis and 42.4% (24/58) among eyes that did. There was no VH in eyes that received laser ablation of the pars plana using overlapping 1,000-ms spots; pars plana cautery or diathermy was less effective. The majority of all VH cases (83.3% [45/54]) were of mild to moderate severity (involving ≤25% of the fundus). CONCLUSION: In this minipig surgical model of VH, scleral dissection followed by pars plana laser ablation before pars plana incision most effectively mitigated VH secondary to PDS implant insertion.