Study to Evaluate Ultevursen in Subjects With Retinitis Pigmentosa (RP) Due to Mutations in Exon 13 of the USH2A Gene

Prior treatment

• Presence of unstable concurrent cystoid macular edema (CME), or subject started on (or changed dose of) any medication for CME in the 3 months prior to enrollment. CME is allowed if stable for 3 months (with or without treatment). However, stable CME that disrupts the EZ width measurement, as determined by CRC, is an exclusion.
• Any intraocular surgery within 3 months of study entry or any planned intraocular or peri-ocular surgery during the study. Subjects may be eligible after 3 months post-surgery as long as they have fully recovered, in the opinion of the Investigator.
• Receipt of any IVT injection prior to study entry.

Other illness

• Presence of additional non-exon 13 USH2A pathogenic or likely pathogenic variant on the USH2A allele carrying the exon 13 mutation in subjects who have one exon 13 disease causing variant and one non-exon 13 disease causing variant.
• Presence of pathogenic or likely pathogenic variants in genes (other than the USH2A gene) which are known to be associated with other inherited retinal degenerative diseases or syndromes. Specifically, the presence of homozygous or compound heterozygous known disease-causing mutations in other genes involved in recessive retinal dystrophies, or the confirmed presence of a known single disease-causing variant in genes involved in dominant, X-linked, or mitochondrial retinal dystrophy genes is exclusionary.

Lab values

• Presence of any significant ocular or non-ocular disease/disorder (including medication and laboratory test abnormalities) which, in the opinion of the Investigator may either put the subject at risk because of participation in the study, may impact the subject's ability to participate in the study, or may interfere with assessment of efficacy and safety in the study.

Other

• Presence of additional non-exon 13 USH2A pathogenic mutation(s) on both USH2A alleles in subjects who have biallelic exon 13 mutations.
• At screening, the EZ horizontal or vertical width are outside the field of the SD-OCT scan based on the assessment of the CRC.

• An adult (≥18 years) willing and able to provide informed consent for participation prior to performing any study related procedures
• OR A minor (8 to \<18 years) able to provide age-appropriate assent for study participation with a parent or legal guardian willing and able to provide written permission for the subject's participation prior to performing any study related procedures. An adult willing to comply with the protocol, follow study instructions, attend study visits as required and willing and able to complete all study assessments, in the opinion of the Investigator.
  • OR A minor able to complete all study assessments and comply with the protocol and has a parent or caregiver willing and able to follow study instructions and attend study visits with the subject as required, in the opinion of the Investigator.
• Both eyes exhibit clinical presentation consistent with RP involving Usher syndrome type 2 or NSRP based on ophthalmic, audiologic, or vestibular examinations. At screening, the Investigator will make the clinical diagnosis of "Usher syndrome type 2a," defined as RP with congenital hearing loss, or "non-syndromic RP," defined as RP without congenital hearing loss.
• A molecular diagnosis of biallelic disease causing variants (pathogenic or likely pathogenic) in the USH2A gene where at least one of the variants is located on exon 13. A historic genotyping report from a certified laboratory is acceptable with Sponsor approval.
• Clearly visible and measurable SD-OCT horizontal EZ width of ≥2.2 mm in both eyes based on the assessment of the CRC.
• BCVA ≥55 letters based on ETDRS (equivalent to 20/80 based on Snellen notation, or logarithm of the minimum angle of resolution \[logMAR\] +0.6) in both eyes.
• Impairment of VF as assessed by SP with a mean sensitivity greater than 4 decibels (dB) and less than 25 dB measured by a V target size in the TE at screening.
• Mean sensitivity greater than 2 dB as determined by MP in the TE at screening.
• Symmetry of baseline disease in both eyes, defined as the mean BCVA (based on ETDRS) of one eye within ≤10 letters of the mean BCVA of the other eye at screening.