Atsena Therapeutics announced the U.S. Food and Drug Administration (FDA) has cleared the company’s Investigational New Drug (IND) application for a phase 1/2 clinical trial of ATSN-201 in patients with X-linked retinoschisis (XLRS).
ATSN-201 leverages one of the company’s novel spreading capsids, AAV.SPR, to overcome the challenges associated with intravitreally delivered AAVs in the treatment of XLRS.
“Intravitreally delivered AAVs have limitations, as they do not drive sufficient gene expression in photoreceptors to confer therapy and can lead to vision-compromising inflammation,” said Shannon Boye, PhD, founder and director of Atsena Therapeutics. “AAV.SPR is well-suited for use in XLRS as it can drive therapeutic levels of gene expression in photoreceptors while avoiding the surgical risks of foveal detachment, which is important because XLRS patients have fragile retinas due to the presence of schisis lesions. Building on decades of research, we’re excited to progress our novel gene therapy for patients with XLRS who currently lack an approved treatment option.”
“With the FDA’s clearance of the IND application for ATSN-201, we’re preparing to advance our first program utilizing AAV.SPR into the clinic for the treatment of XLRS in mid-2023,” said Kenji Fujita, CMO of Atsena Therapeutics. “We look forward to evaluating ATSN-201 and addressing the unmet need for a treatment to improve or restore vision in patients with XLRS.”
The Lighthouse Study, a phase 1/2, open-label, dose-escalation clinical trial, will evaluate subretinal injection of ATSN-201 in male patients ages 6-65 with a clinical diagnosis of XLRS caused by pathogenic or likely pathogenic mutations in RS1.
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 the layers of the retina, which causes impaired visual acuity that is not correctable with glasses and leads to progressive vision loss. 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 AAV.SPR
AAV.SPR, one of Atsena’s novel spreading 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 stark contrast to benchmark vector AAV5, which remains confined to the original bleb margins. At clinically relevant doses, AAV.SPR efficiently transduces foveal cones without the need for surgical detachment and does not cause inflammation.