Outcome of Regenerative Medicine Advanced Therapy (RMAT) meeting provides clear regulatory pathway to approval in a continuous Phase 1 / 2 / 3 study, avoiding the requirement for an additional registrational study and accelerating time to potential approval
Expansion builds on favorable efficacy and safety data from Part A of the LIGHTHOUSE study
Enrollment of pivotal cohort expected to begin in Q1 2026; BLA submission anticipated in early 2028
ATSN-201 on track to potentially be the first gene therapy and one-time treatment for XLRS
DURHAM, N.C., July 09, 2025 (GLOBE NEWSWIRE) -- Atsena Therapeutics, a clinical-stage gene therapy company focused on using the life-changing power of genetic medicine to reverse or prevent blindness, today announced that the U.S. Food and Drug Administration (FDA) has agreed to the expansion of the company’s ongoing Phase 1 / 2 LIGHTHOUSE study of ATSN-201 into a continuous Phase 1 / 2 / 3 trial, enabling it to serve as a pivotal trial to support a Biologics License Application (BLA) submission for the treatment of X-linked retinoschisis (XLRS). The BLA submission is anticipated in early 2028.
“This regulatory milestone marks another significant step toward delivering a potentially first- and best-in-class gene therapy for patients living with XLRS,” said Patrick Ritschel, MBA, Chief Executive Officer of Atsena Therapeutics. “The Agency’s agreement will expedite the clinical development of ATSN-201 by at least 1.5 years, compared to a separate Phase 3 clinical trial. If approved, this would be the first available treatment for XLRS, offering hope to patients and families affected by this inherited retinal disease. We’re grateful for the FDA’s continued guidance as we continue to advance this trial and prepare for filing a BLA in early 2028.”
The first- and best-in-class gene therapy product candidate has received Regenerative Medicine Advanced Therapy (RMAT), Fast Track, Rare Pediatric Disease and Orphan Drug Designations from the FDA. The regulatory feedback follows an RMAT meeting with the FDA. The Agency agreed on the proposed study design, endpoints and patient population to support potential registration. An additional cohort will be added to the ongoing multicenter trial. In the additional cohort, approximately 30 adult and pediatric patients will be randomized 1:1 between treatment and control groups. Patients in the control group will have the opportunity to receive treatment after one year. Efficacy and safety will be assessed in all patients using measures such as microperimetry, visual acuity and macular structure. The pivotal cohort is anticipated to begin enrolling in the first quarter of 2026 with a pivotal data readout expected in the second half of 2027.
“Data from the ongoing trial show that subretinal delivery of ATSN-201 has been well tolerated to date, including in patients with severe schisis cavities, and has led to encouraging improvements in both retinal structure and visual function,” said Kenji Fujita, MD, Chief Medical Officer of Atsena Therapeutics. “This program marks the first clinical use of our laterally spreading subretinal vector, offering important proof of principle for our ocular gene therapy platform. With the study’s expansion, we’re positioned to generate the pivotal data needed to potentially bring the first treatment for XLRS across the finish line.”
Currently, there are no approved treatments for XLRS, which is typically diagnosed in early childhood and affects approximately 30,000 males in the U.S. and the EU combined. The LIGHTHOUSE study is a dose-escalation and dose-expansion clinical trial in male patients ages six and older with a clinical diagnosis of XLRS caused by mutations in the RS1 gene. Enrollment for this study is ongoing. For more information, visit ClinicalTrials.gov (Identifier: NCT05878860).
About X-linked Retinoschisis (XLRS)
XLRS is a monogenic X-linked disease caused by mutations in the RS1 gene which encodes retinoschisin, a protein secreted primarily by photoreceptors. RS1 is localized to the extracellular surface of rods, cones and bipolar cells. XLRS is characterized by schisis, or abnormal splitting of retinal layers, which causes impaired visual acuity that is not correctable with glasses and leads to progressive vision loss and ultimately blindness. XLRS primarily affects males and is typically diagnosed in early childhood. Approximately 30,000 males in the U.S. and EU have XLRS, for which there are currently no approved treatments.
About ATSN-201
ATSN-201 is Atsena’s investigational gene therapy leveraging AAV.SPR, a novel laterally spreading capsid designed to efficiently target photoreceptors in the central retina while avoiding the surgical risks of foveal detachment. ATSN-201 is the first XLRS gene therapy to demonstrate efficacy and positive safety data in a Phase 1 / 2 trial. The majority of patients in Part A of the trial demonstrated improvements in retinal structure (foveal schisis closure) and meaningful improvements in retinal and visual function as assessed by microperimetry, best-corrected visual acuity and low-luminance visual acuity. ATSN-201 has demonstrated a favorable safety profile and has been well-tolerated up to one year post-treatment. No serious adverse events have been reported. If approved, ATSN-201 will be the first gene therapy approved for XLRS. The first- and best-in-class gene therapy product candidate has received Regenerative Medicine Advanced Therapy, Fast Track, Rare Pediatric Disease and Orphan Drug Designations from the U.S. Food and Drug Administration.
About AAV.SPR
AAV.SPR, one of Atsena’s novel capsids, spreads laterally beyond the subretinal injection site to enable safe and efficient transduction of the central retina (where schisis cavities predominate in XLRS patient retinas) when injected into areas outside the macula. A preclinical study in non-human primates demonstrated that AAV.SPR promotes transgene expression well beyond subretinal injection bleb margins. This is in contrast to benchmark AAV vectors, which remain confined to the original bleb margins. At clinically relevant doses, AAV.SPR efficiently transduces foveal cones without the need for surgical detachment and has a favorable safety profile relative to benchmark capsids. For more information about the preclinical study and how AAV.SPR works, visit https://atsenatx.com/our-approach/laterally-spreading-aav/.
About Atsena Therapeutics
Atsena Therapeutics (“Atsena”) is a clinical-stage gene therapy company developing best-in-class treatments for the reversal or prevention of blindness from inherited retinal diseases. The company’s lead program is evaluating ATSN-201 in an ongoing Phase 1 / 2 / 3 clinical trial for X-linked retinoschisis (XLRS), a genetic condition typically diagnosed in childhood and leads to blindness later in life. ATSN-101, Atsena’s first-in-class, investigational gene therapy for Leber congenital amaurosis type 1 (LCA1), has completed a Phase 1 / 2 trial with positive results (https://doi.org/10.1016/s0140-6736(24)01447-8). Atsena is advancing ATSN-101 toward the initiation of a global pivotal trial as part of its exclusive strategic collaboration with Nippon Shinyaku Co., Ltd. Atsena’s pipeline is powered by novel adeno-associated virus (AAV) technology tailored to overcome the hurdles presented by inherited retinal diseases. Founded by pioneers in ocular gene therapy, Atsena is led by an experienced team dedicated to addressing the needs of patients with vision loss. For more information, please visit https://atsenatx.com/.
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