Sustained Ocular Delivery of Bevacizumab Using Densomeres in Rabbits: Effects on Molecular Integrity and Bioactivity.

Purpose: To demonstrate that a single administration of an anti-angiogenic monoclonal antibody, when integrated into a novel biodegradable Densomere composed only of the active pharmaceutical ingredient and polymer, maintains molecular integrity, sustained release, and prolonged bioactivity in vitro and in vivo for up to 12 months. Methods: Bevacizumab, a high-molecular-weight antibody (140,000-150,000 Da) was incorporated at 5% loading into Densomere microparticle carriers (DMCs) for injection to observe in vitro release over time from an aqueous suspension. The molecular integrity of the released bevacizumab was assessed by enzyme-linked immunosorbent assay (ELISA) and size-exclusion chromatography-high-performance liquid chromatography (SEC-HPLC). Anti-angiogenic bioactivity in vivo was assessed using the rabbit corneal suture model for suppression of neovascular encroachment from the limbus following a single subconjunctival administration. Results: Continuous release of bevacizumab in vitro was observed in serial samples over a period of 12 months. ELISA and SEC-HPLC yielded profiles from aqueous supernatant samples indistinguishable from the reference bevacizumab. A single subconjunctival administration in rabbit eyes significantly suppressed corneal neovascularization in vivo compared to control eyes for 12 months. Conclusions: The Densomere carrier platform maintained the molecular integrity of bevacizumab with a prolonged release profile in vitro and demonstrated sustained in vivo drug delivery with continuous bioactivity in the rabbit cornea eye model for 12 months. Translational Relevance: The Densomere platform provides a significant opportunity for prolonged delivery of biologics in ocular and other tissues.

LONG-TERM PHYSICAL STABILITY, STERILITY, AND ANTI-VEGF BIOACTIVITY OF REPACKAGED BEVACIZUMAB IN 2-ML GLASS VIALS.

PURPOSE: Repackaged bevacizumab in single-dose, prefilled syringes for intravitreal injection is available, but with shelf life limited from 60 days to 90 days. For the Study of COmparative Treatments for REtinal Vein Occlusion 2 (SCORE2), 2-mL sterile glass vials were used rather than prefilled syringes to provide a longer shelf life for study supplies. METHODS: Repackaged bevacizumab in glass vials was tested at release and, for 1 lot, after 1, 3, 6, and 12 months for physical stability, including concentration, purity and appearance, and for sterility and endotoxins. Vials from 2 lots were tested at release and after 20 months and 21 months, respectively. One lot was tested at 21 months for anti-VEGF bioactivity compared with a fresh supply of commercial bevacizumab. RESULTS: Repackaged bevacizumab in 2-mL glass vials continued to meet all quality release specifications and remain sterile for up to 21 months. In addition, no degradation in anti-VEGF bioactivity was observed at 21 months compared with a fresh bevacizumab control. CONCLUSION: Bevacizumab can be repackaged into small, single-dose glass vials for intravitreal injection and the qualities of the commercial product maintained, including anti-VEGF bioactivity, for up to 21 months in refrigerated storage. Consideration should be given to repackaging bevacizumab for ophthalmic use in small glass vials as opposed to plastic syringes.

Initial evaluation of subcutaneous daclizumab treatments for noninfectious uveitis: a multicenter noncomparative interventional case series.

PURPOSE: To assess the feasibility of a study design that may determine whether subcutaneous administration of the interleukin-2 receptor antibody daclizumab can safely reduce the dependence on standard systemic corticosteroids or other immunosuppressive regimens in patients with sight-threatening, noninfectious intermediate uveitis, posterior uveitis, or panuveitis. DESIGN: Prospective, multicenter, nonrandomized, noncomparative, open-label interventional trial. PARTICIPANTS: Fifteen patients, 5 each at 3 clinical centers, with noninfectious intermediate, posterior, or panuveitis, who require a currently stable immunosuppression regimen of systemic corticosteroids and/or other systemic treatments to control noninfectious intraocular inflammation. METHODS: After enrollment and baseline ophthalmic evaluations, 2 induction treatments were given 2 weeks apart using subcutaneous (SC) daclizumab at 2 mg/kg. Subcutaneous daclizumab maintenance treatments were then continued every 2 weeks at 1 mg/kg for 6 months. The initial immunosuppression load was tapered over 8 to 12 weeks in a staggered fashion beginning with the first induction treatment. Safety evaluations were performed at each treatment visit, with a primary efficacy evaluation at 12 weeks and a repeat efficacy evaluation at 26 weeks. MAIN OUTCOME MEASURES: Best-corrected visual acuity (Early Treatment of Diabetic Retinopathy Study [ETDRS] method) with a concurrent taper of concomitant systemic immunosuppression medication load (tabulated by use of a weighted scoring system) was assessed; target for success was defined as a 50% or greater reduction in concomitant immunosuppression load by 12 weeks while maintaining visual acuity within 5 ETDRS letters of baseline. Ocular inflammation was assessed at each visit with standardized grading scales. RESULTS: Ten of 15 patients (67%) receiving SC daclizumab treatments every other week successfully achieved the primary efficacy end point of reducing their concomitant immunosuppression load by at least 50% while maintaining their baseline visual acuity at 12 and 26 weeks. Subcutaneous daclizumab injections were well tolerated with no serious adverse events observed during the 6 months of treatments, although 3 patients experienced possibly related, nonserious adverse events. CONCLUSIONS: Subcutaneous daclizumab induction treatments at 2 mg/kg followed by 1 mg/kg maintenance treatments every other week seems safe and, in most cases, may reduce the concomitant immunosuppressive load required to treat noninfectious uveitis for 12 to 26 weeks.

Humanized anti-interleukin-2 (IL-2) receptor alpha therapy: long-term results in uveitis patients and preliminary safety and activity data for establishing parameters for subcutaneous administration.

Therapy for severe uveitis is frequently long-term immunosuppression using systemic corticosteroids and cytotoxic agents, but side effects make long-term therapy difficult. A long-term (>4 year) Phase I/II single armed interventional study using intravenous anti-IL-2 receptor alpha treatments (daclizumab) and a short-term Phase II study evaluating the use of a subcutaneous daclizumab formulation were conducted. Patients were tapered off their systemic immunosuppressive therapy and received daclizumab infusions or subcutaneous injections at intervals varying from 2 to 6 weeks. In the long-term study, seven of ten enrolled patients were tapered from their original immunosuppressive medications and maintained exclusively on repeated daclizumab infusions for control of their uveitis for over 4 years. No patient was permanently removed from therapy for an adverse event ascribed to the medication. The use of 6-week infusion intervals led to recurrence of uveitis, while 2- to 4-week intervals did not. Only one patient developed measurable anti-daclizumab antibodies but this disappeared when subcutaneous therapy was begun. In the short-term study, four of the five patients receiving the subcutaneous formulation met the study endpoints for success within the first 12 weeks. All five were successful by 26 weeks. These studies provide preliminary evidence that regularly administered long-term daclizumab therapy can be given in lieu of standard immunosuppression for years to treat severe uveitis and that subcutaneously administered daclizumab appeared to be a clinically viable treatment strategy. These studies suggest that anti-IL-2 receptor blockade could be useful in the treatment of Th1-mediated autoimmune conditions.