Intravitreal RTH258 (brolucizumab) demonstrates no effect on pregnancy, parturition, embryofetal or postnatal development in cynomolgus monkeys.

RTH258 (brolucizumab) is a humanized single chain antibody fragment, the smallest functional unit of an antibody designed to target vascular endothelial growth factor in angiogenic retinal disease. To further understand the safe use of RTH258, this study assessed the potential impact of intravitreal RTH258 on pre- and postnatal development in the offspring of cynomolgus monkeys following administration to the mother. Three groups of 16 pregnant females were included: a low dose group (RTH258 3 mg/50 µl [60 mg/ml]), a high dose group (RTH258 6 mg/50 µl [120 mg/ml]), and a control group. Maternal animals were administered a single injection of 50 µl in the right eye once every four weeks. Animals were observed daily and detailed observations were collected before and after the first dose, and then weekly thereafter. Following parturition, observations of infants included external, morphological, and ophthalmic examinations; neurobehavioral test battery; grip strength; and skeletal development. Blood samples for hematology, coagulation, and clinical chemistry were collected from non-fasted maternal and infant animals. No RTH258-related deaths occurred in maternal dams or infants. No RTH258-related clinical observations were noted in maternal animals or in surviving infants - there were no changes in gestation length; pregnancy loss; deaths; body weight/weight change; infant grip strength; infant external, morphological, or skeletal evaluations; ophthalmoscopy or neurobehavioral observations; or clinical pathology parameters. RTH258 had no impact on pregnancy or parturition; embryo-fetal development; or survival, growth, or postnatal development of offspring when administered via repeated intravitreal administration.

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.

An Anti-CD22-seco-CBI-Dimer Antibody-Drug Conjugate (ADC) for the Treatment of Non-Hodgkin Lymphoma That Provides a Longer Duration of Response than Auristatin-Based ADCs in Preclinical Models.

We are interested in developing a second generation of antibody-drug conjugates (ADCs) for the treatment of non-Hodgkin lymphoma (NHL) that could provide a longer duration of response and be more effective in indolent NHL than the microtubule-inhibiting ADCs pinatuzumab vedotin [anti-CD22-vc-monomethyl auristatin E (MMAE)] and polatuzumab vedotin (anti-CD79b-vc-MMAE). Pinatuzumab vedotin (anti-CD22-vc-MMAE) and polatuzumab vedotin (anti-CD79b-vc-MMAE) are ADCs that contain the microtubule inhibitor MMAE. Clinical trial data suggest that these ADCs have promising efficacy for the treatment of NHL; however, some patients do not respond or become resistant to the ADCs. We tested an anti-CD22 ADC with a seco-CBI-dimer payload, thio-Hu anti-CD22-(LC:K149C)-SN36248, and compared it with pinatuzumab vedotin for its efficacy and duration of response in xenograft models and its ability to deplete normal B cells in cynomolgus monkeys. We found that anti-CD22-(LC:K149C)-SN36248 was effective in xenograft models resistant to pinatuzumab vedotin, gave a longer duration of response, had a different mechanism of resistance, and was able to deplete normal B cells better than pinatuzumab vedotin. These studies provide evidence that anti-CD22-(LC:K149C)-SN36248 has the potential for longer duration of response and more efficacy in indolent NHL than MMAE ADCs and may provide the opportunity to improve outcomes for patients with NHL.

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.

Rapid Development of Glaucoma Via ITV Nonselective ANGPT 1/2 Antibody: A Potential Role for ANGPT/TIE2 Signaling in Primate Aqueous Humor Outflow.

Purpose: Investigate a significant, dose-related increase in IOP, leading to glaucomatous damage to the neuroretina and optic nerve following intravitreal (ITV) administration of a bispecific F(ab')2 [anti-VEGF/Angiopoietins [ANGPT]F(ab')2] molecule in adult monkeys. Methods: ITV ocular tolerability and investigation of anti-VEGF/ANGPT F(ab')2 (blocking both ANGPT1 and ANGPT2) was done in monkeys; mechanistic studies were done in neonatal mice. Results: Following the second ITV dose of anti-VEGF/ANGPT F(ab')2, all 1.5- and 4-mg/eye treated monkeys developed elevated IOP, which eventually was associated with optic disc cupping and thinning of the neuroretinal rim. Histopathologic examination showed nonreversible axonal degeneration in the optic nerves of animals administered 1.5 mg/eye and higher that was considered secondary to high IOP. Anti-ANGPT Fab also caused elevated IOP in monkeys, but anti-VEGF Fab did not contribute to the IOP increase. In addition, an anti-ANGPT2-selective antibody did not change IOP. In mice simultaneous blockade of ANGPT1 and ANGPT2 impaired the expansion and formation of Schlemm's canal (SC) vessels, similar to genetic ablation of Angpt1/Angpt2 and their receptor TIE2. As previously reported, blocking ANGPT2 alone did not affect SC formation in mice. Conclusions: Dual inhibition of ANGPT1/ANGPT2, but not ANGPT2 alone, leads to increased IOP and glaucomatous damage in monkeys. This confirms a role for TIE2/ANGPT signaling in the control of IOP in adults, a finding initially identified in transgenic mice. Dual pharmacologic inhibition of ANGPT1/ANGPT2 may affect aqueous drainage and homeostasis in adult monkeys and may be useful in developing novel models of glaucoma.

The transgenic expression of LARGE exacerbates the muscle phenotype of dystroglycanopathy mice.

Mutations in fukutin-related protein (FKRP) underlie a group of muscular dystrophies associated with the hypoglycosylation of α-dystroglycan (α-DG), a proportion of which show central nervous system involvement. Our original FKRP knock-down mouse (FKRP(KD)) replicated many of the characteristics seen in patients at the severe end of the dystroglycanopathy spectrum but died perinatally precluding its full phenotyping and use in testing potential therapies. We have now overcome this by crossing FKRP(KD) mice with those expressing Cre recombinase under the Sox1 promoter. Owing to our original targeting strategy, this has resulted in the restoration of Fkrp levels in the central nervous system but not the muscle, thereby generating a new model (FKRP(MD)) which develops a progressive muscular dystrophy resembling what is observed in limb girdle muscular dystrophy. Like-acetylglucosaminyltransferase (LARGE) is a bifunctional glycosyltransferase previously shown to hyperglycosylate α-DG. To investigate the therapeutic potential of LARGE up-regulation, we have now crossed the FKRP(MD) line with one overexpressing LARGE and show that, contrary to expectation, this results in a worsening of the muscle pathology implying that any future strategies based upon LARGE up-regulation require careful management.

Ectopic thyroid in the aortic valve of a Han Wistar rat.

Histological examination of the heart of a clinically normal, 10-week-old female Han Wistar rat revealed a 600 x 400-mum mass of ectopic thyroid tissue within the subendothelial connective tissue of the aortic valve. The mass protruded into the left ventricular lumen and was composed of single layers of cuboidal to low-columnar epithelium organized into follicles often containing colloid. Parafollicular cells were not evident. To the authors' knowledge, this is the first report of intracardiac ectopic thyroid gland in the rat and the first report of ectopic thyroid within a heart valve in a mammal.

Congenital intrahepatic vascular anomaly in a clinically normal laboratory beagle.

Routine necropsy examination of a clinically normal, ten-month-old male beagle dog identified disruption of the dorsal aspect of the right median liver lobe by a multiloculated, pale tan-white, thick-walled mass, with diffuse hypertrophy of the left and caudate liver lobes. The nature of the lesion was investigated using a variety of immunohistochemical and histochemical techniques. Histologically, the lesion was characterized by marked, focally extensive vascular hyperplasia and ectasia with lobular atrophy, periportal fibrosis, and biliary hyperplasia. The endothelium of proliferating vessels was positive for von Willebrands factor, and proliferating bile ducts were positive for pancytokeratin. Based on the gross and histologic appearance, this lesion was identified as a vascular hamartoma with arteriovenous fistula. It is important to note that this spontaneous lesion may occur in the laboratory beagle in the absence of clinical signs.