ABSTRACT
Purpose : Autosomal recessive CEP290-LCA (LCA10) is a severe inherited retinal disease resulting in early vision loss and currently has no treatment. Sepofarsen is an RNA antisense oligonucleotide targeting the most common c.2991+1655A>G disease-causing variant in the CEP290 gene. Long-term safety and efficacy of sepofarsen in the first eye treated (FE) and safety and efficacy in the second eye treated (SE) in this extension trial (Insight;NCT03913130) were evaluated. Methods : Subjects who completed the Ph1b/2 sepofarsen trial could enroll in the extension trial for continued dosing in the FE and initiation in the SE with the 160/80μg loading/maintenance dose. Frequency and severity of adverse events, and change in best-corrected visual acuity (BCVA) and full-field stimulus testing (FST) threshold were assessed. Baseline was defined as the value measured within the same month of-or last measurement prior to-the first dosing for each eye. Due to covid-19, some participants have missed scheduled injections. As such data up to-or available measurement prior to-6 months after the last dosing have been included in the analysis for each eye. Results : At data cut-off in mid-October 2021, 9 subjects (of 11 from the Ph1b/2 trial) aged 15-45 years were followed up to 46 months, 5 of them received at least one intravitreal injection of sepofarsen in the SE. Three subjects developed cataracts in the FE and 2 in the SE, of which 2 recovered following cataract surgery. Time to onset since initial dose was 13 months or later. Between 35-46 months after the 1 injection, long term BCVA improvement was reported in 4/6 FE ranging from-0.20 to-0.54 logMAR and 5/5 FE improved in either blue FST, red FST or both ranging from-0.21 to-2.06 log cd/m2. The SE showed a similar trend as the FE in BCVA (3/5 SE showed a change ranging from-0.06 to-2.50 logMAR) and in blue and red FST (4/4 SE showed improvement ranging from-0.27 to-4.57 log cd/m2). st Conclusions : The longer-term sepofarsen safety profile is consistent with that observed in the Ph1b/2. Meaningful BCVA and FST improvements observed in the Ph1b/2 continued up to 46 months. The responses in the SE were similar to the responses seen in the FE in both visual acuity and retinal sensitivity improvements. A Phase 2/3 (ILLUMINATE;NCT03913143), multiple dose, double-masked, randomized, sham-controlled trial is ongoing.
ABSTRACT
Purpose : To assess toxicity and efficacy of subretinal gene replacement in BBS10 mice. Overexpression toxicity in BBS1 mice occurred with gene therapy;BBS1 is part of the BBSome, while BBS10 is part of the BBS/CCT chaperonin complex. Methods : A knock out mouse model of Bardet Biedl Syndrome type 10 (BBS10) was developed. AAV2/5-Bbs10FLAG and AAV2/Anc80-Bbs10FLAG vectors were created. Subretinal 2 ul injections of 1E12, 2E12 or 4E12VG/ml were performed in 62 Bbs10-/-and 12 WT mice. Immunoblotting and immunohistochemistry were utilized to assess protein production and restoration of Bbs10 gene function. ERG, OCT, and visually guided swim assay (VGSA) were used to assess efficacy. Due to COVID-19, long term data was collected only for 12 mice treated with 2E9 or 4E9 AAV2/Anc80-Bbs10FLAG and 3 controls. Results : Neither AAV2/5-Bbs10FLAG nor AAV2/Anc80-Bbs10FLAG were toxic in WT or Bbs10-/-. One month after injection, FLAG was detected in treated, but not untreated Bbs10-/-eyes, documenting presence of BBS10 protein.BBS7,undetectable or barely detectable within photoreceptor cilia in untreated Bbs10 eyes,was present in photoreceptor cilia in treated Bbs10 eyes.VGSA was partially rescued via either AAV2/5 or AAV2/Anc80 treated at P30-P60 when tested in the dark at age 3.5 months(p= 1.36E005)and in both light and dark at age 7 months (p=. <0.0001 light;p= 0.0094 dark). VGSA improvement endured in AAV2/Anc80 treated mice at 9-12 months old(p=0.0113). Treated eyes had higher amplitude ERG than untreated fellow eyes at 10-11.5 months old (highest p=0.0425). OCT at 11-14 months demonstrated presence of outer nuclear layer in 5/11 treated eyes compared to 0/11 untreated fellow eyes and 0/6 untreated control eyes. 5Hz flicker response was not present at any age in untreated Bbs10 (n=18 eyes), but developed in 9 of 12 eyes treated before 4 months old. 4 of 12 treated eyes still had recordable 5 Hz at 11-14 mos, all treated with 4E9. Histology at 11 months demonstrated robust ONL, inner and outer segments with numerous cones, and normal localization of STX3 adjacent to the injection site in 2 treated eyes. Conclusions : In the Bbs10 mouse subretinal gene therapy with AAV2/Anc80-Bbs10FLAG rescues retinal phenotype . Lack of 5 Hz flicker ERG response in untreated eyes was rescued with early high titer gene therapy suggesting that BBS10 plays an early role in cone development and/or function. Human BBS10 clinical trials are needed.