Characterization and Potential Mitigation of Corneal Effects in Nonclinical Toxicology Studies in Animals Administered Depatuxizumab Mafodotin

Purpose: To characterize the ocular toxicity of an antibody-drug conjugate (ADC), depatuxizumab mafodotin (Depatux-m), in nonclinical species and to evaluate the effects of drug-antibody ratios (DARs), variations of the ADC construct, and potential methods for mitigation of the corneal toxicity. Depatux-m contains the potent cytotoxic agent monomethyl auristatin F as the ADC payload. Methods: Depatux-m was administered intravenously to cynomolgus monkeys at doses up to 30 mg/kg and to mice up to 100 mg/kg. Ocular toxicity was evaluated by clinical ophthalmic examinations and histopathology. Potential mitigation was tested through agents to block target engagement and multiple topical ophthalmic treatments (antioxidant, vasoconstrictor, tear stimulant). Results: Effects primarily involved corneal epithelium and were dose-dependent with respect to onset, severity, and time to reversal in both monkeys and mice. On slit lamp biomicroscopy, the initial effect in monkeys was superficial multifocal punctate opacities (granularity), which migrated axially and were followed by pigmentation and multifocal punctate fluorescein staining. Microscopically, findings were characterized by single-cell necrosis, pigmentation, disordered basilar layer, and thinning of the corneal epithelium. Increased toxicity was associated with a higher DAR or more stably attached linker. Treatment with agents to block target engagement did not affect toxicity, and none of the topical treatments was successful. Conclusions: The corneal findings observed were similar to the effects described in clinical trials with Depatux-m and other ADCs. Collectively, these studies and available literature support the hypothesis that ADC-mediated toxicity is driven primarily by mechanism of action of the payload.

Clinical and Optical Coherence Tomography Analysis of Intraretinal Microcysts in Patients with Epiretinal Membrane

Purpose: To perform clinical and optical coherence tomography analysis of intraretinal microcysts (IRM) in patients undergoing pars plana vitrectomy (PPV) for primary epiretinal membrane (ERM) treatment.Materials and Methods: The files of 137 patients who were operated on by a single surgeon for primary epiretinal membrane treatment in our clinic between September 2017 and January 2020 were retrospectively reviewed. Patients with ERM due to secondary pathology were excluded from the study. Twenty patients with post-operative IRM (group 1) were determined and were included as the study group. To determine the effect of IRMs on visual acuity 20 patients who did not have IRM, had primary ERM and underwent PPV for treatment were included as the control group (group 2). The demographic, clinical, and operative data of the patients were obtained from the hospital database. Retinal analysis of the patients before the operation and at the earliest 6 months after the operation was performed using 6 × 6 mm images taken with the macular cube 512 × 128 protocol on the Cirrus HD-OCT (Carl Zeiss Meditec, Dublin, CA, USA) device in our clinic.Results: Intraretinal microcysts were present in 8 (5.8%) of preoperative 137 patients and 20 (14.6%) of 137 postoperative patients. All 8 patients with preoperative cysts in group 1 also had postoperative IRMs. Excluding patients with preoperative cysts, the postoperative IRM incidence was found to be 12/137 (8.75%). Preoperative (p = .392) and postoperative (p = .978) visions were similar in group 1 and group 2. Preoperative (p = .745) and postoperative retinal thicknesses were similar in both groups (p = .989). The incidence of postoperative (p = .642) IRM was similar in patients who underwent ERM and ERM + internal limiting membrane (ILM) peeling in group 1.Conclusions: Intraretinal microcysts may sometimes be seen before and after ERM surgery. The preoperative cyst presence in ERM patients is an important risk factor for postoperative cyst presence. The peeling of ILM with ERM does not increase the probability of IRM occurrence. The presence of these cysts before and/or after the operation does not affect the visual prognosis and macular thickness in ERM patients.

Comparative Analysis of miRNA Expressions in Different Developmental Stages of Echinococcus granulosus in Mono-Phasic and Di-Phasic Culture Systems

BACKGROUND

The dog tapeworm, Echinococcus granulosus, is a zoonotic parasite affecting humans and livestock across the globe. Basic research on the molecular biology and genetics of E. granulosus improves our understanding of the biology and potential drug targets in various developmental stages of E. granulosus in both definitive and intermediate hosts. There has been increasing interest in the identification of microRNAs in parasitic organisms. The purpose of the current study was to compare the activity of a selected profile of miRNAs in different developmental stages of E. granulosus.

METHODS

Different developmental stages of the parasite were obtained from ex vivo as well as in vitro cultured E. granulosus. MicroRNAs were extracted from the ex vivo germinal layer and invaginated protoscoleces as well as the in vitro generated microcysts, evaginated protoscoleces, and strobilated worms. The expression of the selected miRNAs was evaluated by RT-qPCR for each stage.

RESULTS

Four out of five miRNAs were present and active in different developmental stages of E. granulosus. A significant over-expression of miR-61 was observed in the germinal layer and during the protoscolex transformation into the microcysts, however, miR-10 was more expressed in the mature strobilated forms than in the other stages. Let-7 and miR-3489 showed a high expression in the germinal layer.

CONCLUSION

Differential expression of four miRNAs among different in vitro and ex vivo developmental stages of E. granulosus was documented in the present study. Further experimental investigations are required to elucidate the probable role of the miRNAs in bi-directional differentiation of protoscoleces either into the strobilated worm or to a secondary hydatid cyst and the potential of these miRNAs as drug targets.

Treatment with sodium hyaluronate eye drops in a patient who had early-onset bleb leakage after trabeculectomy with mitomycin C

We present the case of a 47-year-old man who had bilateral proliferative diabetic retinopathy and neovascular glaucoma. Schirmer I test revealed tear secretions of 5 mm and 3 mm in the right and left eyes, respectively. Tear breakup times in the right and left eyes were 7 and 8 seconds, respectively. The ocular surface staining in both eyes was scored as Grade 1 as per the Oxford scheme. Retinal photocoagulation was performed for correction of the proliferative diabetic retinopathy and rubeosis iridis, which resolved with treatment. However, the intraocular pressure in the left eye could not be adequately controlled. Therefore, trabeculectomy with mitomycin C using limbal-based conjunctival flap was performed. Three hours after the surgery, the patient developed a large and diffuse filtering bleb, but no leakage occurred from the conjunctival scar. However, on the first postoperative day, leakage was noted and the conjunctiva was at the leakage point. The leakage resolved transiently, but recurred the next day. Severe keratoconjunctival epithelial failure was detected, and the patient was administrated 0.1% sodium hyaluronate eye drops six times daily. The epithelial failure improved, and many microcysts were detected on the bleb surface where the epithelial failure improved. The leakage resolved 2 days after initiation of the sodium hyaluronate eye drops. The microcysts disappeared and the bleb surface became smooth 1 month later.