Safety and efficacy of ATSN-101 in patients with Leber congenital amaurosis caused by biallelic mutations in GUCY2D: a phase 1/2, multicentre, open-label, unilateral dose escalation study.

BACKGROUND: Leber congenital amaurosis 1 (LCA1), caused by mutations in GUCY2D, is a rare inherited retinal disease that typically causes blindness in early childhood. The aim of this study was to evaluate the safety and preliminary efficacy of ascending doses of ATSN-101, a subretinal AAV5 gene therapy for LCA1. METHODS: 15 patients with genetically confirmed biallelic mutations in GUCY2D were included in this phase 1/2 study. All patients received unilateral subretinal injections of ATSN-101. In the dose-escalation phase, three adult cohorts (n=3 each) were treated with three ascending doses: 1·0 × 1010 vg/eye (low dose), 3·0 × 1010 vg/eye (middle dose), and 1·0 × 1011 vg/eye (high dose). In the dose-expansion phase, one adult cohort (n=3) and one paediatric cohort (n=3) were treated at the high dose. The primary endpoint was the incidence of treatment-emergent adverse events (TEAEs), and secondary endpoints included full-field stimulus test (FST) and best-corrected visual acuity (BCVA). A multi-luminance mobility test (MLMT) was also done. Data through the 12-month main study period are reported. FINDINGS: Patients were enrolled between Sept 12, 2019, and May 5, 2022. A total of 68 TEAEs were observed, 56 of which were related to the surgical procedure. No serious TEAE was related to the study drug. Ocular inflammation was mild and reversible with steroid treatment. For patients who received the high dose, mean change in dark-adapted FST was 20·3 decibels (dB; 95% CI 6·6 to 34·0) for treated eyes and 1·1 dB (-3·7 to 5·9) for untreated eyes at month 12 (white stimulus); improvements were first observed at day 28 and persisted over 12 months (p=0·012). Modest improvements in BCVA were also observed (p=0·10). Three of six patients who received the high dose and did the MLMT achieved the maximum score in the treated eye. INTERPRETATION: ATSN-101 is well tolerated 12 months after treatment, with no drug-related serious adverse events. Clinically significant improvements in retinal sensitivity were sustained in patients receiving the high dose. FUNDING: Atsena Therapeutics.

Assessment of Visual Function with Cotoretigene Toliparvovec in X-Linked Retinitis Pigmentosa in the Randomized XIRIUS Phase 2/3 Study.

PURPOSE: Cotoretigene toliparvovec (BIIB112/AAV8-RPGR) is an investigational vector-based gene therapy designed to provide a full-length, codon-optimized retinitis pigmentosa GTPase regulator (RPGR) protein to individuals with RPGR-associated X-linked retinitis pigmentosa (XLRP). We assessed efficacy and tolerability of cotoretigene toliparvovec subretinal gene therapy. DESIGN: Part 2 of the XIRIUS trial (ClinicalTrials.gov identifier, NCT03116113) was a phase 2/3, 12-month, randomized (1:1:1) dose-expansion study. PARTICIPANTS: Male patients ≥10 years of age with RPGR-associated XLRP were included. METHODS: Participants were randomized 1:1:1 to receive low-dose subretinal cotoretigene toliparvovec (5 × 1010 vector genomes/eye), high-dose cotoretigene toliparvovec (2.5 × 1011 vector genomes/eye) or to be an untreated control participant. MAIN OUTCOME MEASURES: The primary end point was the percentage of participants meeting microperimetry responder criteria (≥ 7-dB improvement at ≥ 5 of 16 central loci). Secondary end points included change from baseline in retinal sensitivity at the central 16 loci and the entire 68 loci at 12 months and change from baseline in low-luminance visual acuity (LLVA) at 12 months, as well as the proportion of eyes with a ≥ 15-Early Treatment Diabetic Retinopathy Study ETDRS letter LLVA and ≥ 10-ETDRS letter LLVA change from baseline at month 12. RESULTS: Because of the impact of the COVID-19 pandemic, enrollment ended before reaching the initial target, leaving the trial underpowered. Twenty-nine participants were included (low-dose group, n = 10; high-dose group, n = 10; control group, n = 9). At month 12, the percentage of participants meeting microperimetry responder criteria was not significantly different between either cotoretigene toliparvovec group (low dose, 37.5% [P = 0.3181]; high dose, 25.0% [P = 0.5177]) and the control group (22.2%). However, the mean change from baseline in microperimetry sensitivity improved significantly with the low-dose group versus the control group at month 12 (P = 0.0350). Significant improvement in LLVA occurred in the low-dose group versus the control group at month 12 (33.3% difference [80% confidence interval, 14.7%-55.2%]; P = 0.0498). Three ocular-related serious adverse events (SAEs) occurred in the low-dose group versus 7 SAEs in the high-dose group. CONCLUSIONS: The primary microperimetry end point was not met. Significant improvements in LLVA and mean microperimetry were observed compared with controls and fewer SAEs occured with low-dose compared with high dose cotoretigene toliparvovec. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Tissue-specific genotype-phenotype correlations among USH2A-related disorders in the RUSH2A study.

We assessed genotype-phenotype correlations among the visual, auditory, and olfactory phenotypes of 127 participants with Usher syndrome (USH2) (n =80) or nonsyndromic autosomal recessive retinitis pigmentosa (ARRP) (n = 47) due to USH2A variants, using clinical data and molecular diagnostics from the Rate of Progression in USH2A Related Retinal Degeneration (RUSH2A) study. USH2A truncating alleles were associated with USH2 and had a dose-dependent effect on hearing loss severity with no effect on visual loss severity within the USH2 subgroup. A group of missense alleles in an interfibronectin domain appeared to be hypomorphic in ARRP. These alleles were associated with later age of onset, larger visual field area, better sensitivity thresholds, and better electroretinographic responses. No effect of genotype on the severity of olfactory deficits was observed. This study unveils a unique, tissue-specific USH2A allelic hierarchy with important prognostic implications for patient counseling and treatment trial endpoints. These findings may inform clinical care or research approaches in others with allelic disorders or pleiotropic phenotypes.

Current Clinical Applications of In Vivo Gene Therapy with AAVs.

Hereditary diseases are caused by mutations in genes, and more than 7,000 rare diseases affect over 30 million Americans. For more than 30 years, hundreds of researchers have maintained that genetic modifications would provide effective treatments for many inherited human diseases, offering durable and possibly curative clinical benefit with a single treatment. This review is limited to gene therapy using adeno-associated virus (AAV) because the gene delivered by this vector does not integrate into the patient genome and has a low immunogenicity. There are now five treatments approved for commercialization and currently available, i.e., Luxturna, Zolgensma, the two chimeric antigen receptor T cell (CAR-T) therapies (Yescarta and Kymriah), and Strimvelis (the gammaretrovirus approved for adenosine deaminase-severe combined immunodeficiency [ADA-SCID] in Europe). Dozens of other treatments are under clinical trials. The review article presents a broad overview of the field of therapy by in vivo gene transfer. We review gene therapy for neuromuscular disorders (spinal muscular atrophy [SMA]; Duchenne muscular dystrophy [DMD]; X-linked myotubular myopathy [XLMTM]; and diseases of the central nervous system, including Alzheimer's disease, Parkinson's disease, Canavan disease, aromatic l-amino acid decarboxylase [AADC] deficiency, and giant axonal neuropathy), ocular disorders (Leber congenital amaurosis, age-related macular degeneration [AMD], choroideremia, achromatopsia, retinitis pigmentosa, and X-linked retinoschisis), the bleeding disorder hemophilia, and lysosomal storage disorders.

REPEATABILITY AND LONGITUDINAL ASSESSMENT OF FOVEAL CONE STRUCTURE IN CNGB3-ASSOCIATED ACHROMATOPSIA.

PURPOSE: Congenital achromatopsia is an autosomal recessive disease causing substantial reduction or complete absence of cone function. Although believed to be a relatively stationary disorder, questions remain regarding the stability of cone structure over time. In this study, the authors sought to assess the repeatability of and examine longitudinal changes in measurements of central cone structure in patients with achromatopsia. METHODS: Forty-one subjects with CNGB3-associated achromatopsia were imaged over a period of between 6 and 26 months using optical coherence tomography and adaptive optics scanning light ophthalmoscopy. Outer nuclear layer (ONL) thickness, ellipsoid zone (EZ) disruption, and peak foveal cone density were assessed. RESULTS: ONL thickness increased slightly compared with baseline (0.184 µm/month, P = 0.02). The EZ grade remained unchanged for 34/41 subjects. Peak foveal cone density did not significantly change over time (mean change 1% per 6 months, P = 0.126). CONCLUSION: Foveal cone structure showed little or no change in this group of subjects with CNGB3-associated achromatopsia. Over the time scales investigated (6-26 months), achromatopsia seems to be a structurally stable condition, although longer-term follow-up is needed. These data will be useful in assessing foveal cone structure after therapeutic intervention.

Decreased macular thickness in nonproliferative macular telangiectasia type 2 with oral carbonic anhydrase inhibitors.

PURPOSE: To evaluate whether carbonic anhydrase inhibitors reduce the macular thickness and/or cystic spaces in patients with macular telangiectasia (MacTel) Type 2. METHODS: Retrospective review of patients with nonproliferative cystoid changes associated with MacTel seen at the University of Iowa between 2009 and 2012. Carbonic anhydrase inhibitors were used in 8 patients with MacTel Type 2. Five patients with MacTel Type 2 were observed during this period. Initial and final visual acuities were documented. The presence of cystic spaces and the retinal thickness were measured with spectral-domain optical coherence tomography. RESULTS: Patients treated with oral carbonic anhydrase inhibitors showed significant reduction in both the cystoid cavities and central macular thickness when compared with the patients who were observed (-12.2 µm; P = 0.020). The reduction in retinal thickness was more pronounced in patients receiving acetazolamide (-20.13 µm; P = 0.007) compared with methazolamide (-6.25 µm; P = 0.177). There was no significant change in visual acuity in patients receiving carbonic anhydrase inhibitors. Five patients with MacTel Type 2 did not receive treatment and demonstrated no change in visual acuity, cystoid cavities, or central macular thickness. CONCLUSION: Oral carbonic anhydrase inhibitors, particularly acetazolamide, may decrease macular cystic cavities and reduce central macular thickness but does not appear to improve visual acuity. These findings have yet to be confirmed with a prospective treatment trial.

Spectral domain optical coherence tomography findings in CNGB3-associated achromatopsia and therapeutic implications.

We describe the spectral domain OCT findings in two siblings with CNGB3-associated achromatopsia. A 33-year-old female and her 31-year-old sibling were evaluated for mild nystagmus and decreased visual acuity which had been present since childhood. They were each evaluated with full field Ganzfeld electroretinography which demonstrated flat photopic responses and preserved rod function. Genetic testing performed at Carver lab at the University of Iowa confirmed a diagnosis of achromatopsia with identical mutations in the CNGB3 gene. Spectral domain optical coherence tomography was performed which revealed foveal changes in both siblings, with slight phenotypic variations in these genotypically identical siblings. OCT findings in achromatopsia emphasize the importance of early identification and treatment in this disorder.

Elimination of infusion bubbles and uncontrolled reflux in the alcon constellation vitrectomy vision system.

PURPOSE: To identify the sources and management of 2 problems associated with the Alcon Constellation Vitrectomy (Alcon Laboratories, Inc) System: 1) infusion bubbles and 2) uncontrolled reflux. METHODS: Surgical and analytical videos were evaluated to identify the source of intraoperative bubbles, which localized to the duckbill valve (DV). Intraoperatively, the authors modified the infusion tubing and its control by removing the DV. The DV was repurposed as a one-way valve to block reflux originating from the vitrectomy console. RESULTS: Twenty consecutive 23-gauge vitrectomies in 20 eyes of 20 subjects from 2 surgeons (S.R.R. and E.H.S.) were reviewed. Infusion bubbles at the DV developed with each transitory tubing pressure drop upon opening of the infusion clamp. Removal of the DV from the infusion line eliminated infusion bubbles in 20 consecutive 23-gauge cases. Adding a one-way valve, which was fashioned from the DV, to the aspiration tubing, resulted in elimination of infusion bubbles and console-originated reflux in 20 eyes. Placement of the DV to block reflux eliminated both uncontrolled and purposeful console-originated reflux. CONCLUSION: Intraoperative modification of Constellation tubing may eliminate two potentially harmful problems until manufacturer correction is instituted. Because the authors' modified connections represent off-label connectivity, the manufacturer cannot contact potentially affected surgeons or suggest temporary alternative connectivity improvements.

Acute Macular Neuroretinopathy Following COVID-19 mRNA Vaccination.

A 21-year-old female developed bilateral acute-onset paracentral scotomas three days after receiving the second dose of her Moderna COVID-19 vaccination. A clinical diagnosis of acute macular neuroretinopathy (AMN) was confirmed after classic findings were demonstrated on near-infrared reflectance imaging, spectral-domain optical coherence tomography, and colored fundus photography. The patient presented with visual acuity of 20/100-1 OD and 20/20 OS. After treatment with brimonidine and difluprednate, at a two-week follow-up, her visual acuity was 20/100-2 OD and 20/25-2 OS. There have been reported cases of AMN following flu-like illnesses as well as after receiving vaccines. However, this is the first report of AMN following vaccination with a Moderna COVID-19 vaccine.

Night vision restored in days after decades of congenital blindness.

Signaling of vision to the brain starts with the retinal phototransduction cascade which converts visible light from the environment into chemical changes. Vision impairment results when mutations inactivate proteins of the phototransduction cascade. A severe monogenically inherited blindness, Leber congenital amaurosis (LCA), is caused by mutations in the GUCY2D gene, leading to a molecular defect in the production of cyclic GMP, the second messenger of phototransduction. We studied two patients with GUCY2D-LCA who were undergoing gene augmentation therapy. Both patients had large deficits in rod photoreceptor-based night vision before intervention. Within days of therapy, rod vision in both patients changed dramatically; improvements in visual function and functional vision in these hyper-responding patients reached more than 3 log10 units (1000-fold), nearing healthy rod vision. Quick activation of the complex molecular pathways from retinal photoreceptor to visual cortex and behavior is thus possible in patients even after being disabled and dormant for decades.