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Atsena Therapeutics announces positive clinical data from Phase I/II trial evaluating ATSN-201 gene therapy for X-linked retinoschisis
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According to the company, a subretinal injection of ATSN-201 was well tolerated in all patients in the first cohort with extensive resolution of schisis observed in 2 patients. Safety data from the first cohort of the LIGHTHOUSE study will be presented at the Retinal Cell and Gene Therapy Innovation Summit 2024 being held May 3, 2024, in Seattle.
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Atsena Therapeutics today announced positive preliminary data from the first cohort of the ongoing LIGHTHOUSE study, a Phase I/II clinical trial evaluating subretinal injection of ATSN-201 for the treatment of X-linked retinoschisis (XLRS).
Safety data from the first cohort of the LIGHTHOUSE study will be presented at the Retinal Cell and Gene Therapy Innovation Summit 2024 being held May 3, 2024, in Seattle.
According to a news release, the company noted ATSN-201 utilizes AAV.SPR, the company’s novel spreading capsid, to achieve therapeutic levels of gene expression in photoreceptors of the central retina while avoiding the surgical risks of foveal detachment.
The LIGHTHOUSE study (NCT05878860) is evaluating ATSN-201 in male patients ages 6 and older with a clinical diagnosis of XLRS caused by mutations in the RS1 gene. XLRS is characterized by schisis, or abnormal splitting of retinal layers.1
The company noted this results impaired visual acuity that cannot be corrected with eyeglasses, and leads to progressive vision loss and ultimately blindness. XLRS impacts approximately 30,000 males in the United States and EU and there are no approved treatments.
Moreover, according to the news release, in the first (low-dose) cohort of the LIGHTHOUSE study, two of the three patients showed extensive resolution of schisis beginning at 8 weeks after dosing. Additional and continued resolution of schisis was observed through week 24, the latest time point available. Notably, areas of schisis cavity resolution were found both inside and well outside of the subretinal injection blebs, indicating that AAV.SPR is spreading laterally from the injection blebs, consistent with expectations of this novel, laterally spreading capsid.1
The company noted early efficacy was also observed using microperimetry, with functional improvements seen in the same locations as structural improvements. Improvements of up to 14 dB were seen in one patient, with 38 loci showing an improvement of greater than 7 dB. The FDA considers an improvement of at least 7 dB at 5 or more prespecified loci to be clinically meaningful.
ATSN-201 was well tolerated in all three XLRS patients in the first cohort and no serious adverse events were reported. These results demonstrate, for the first time, the ability to safely administer subretinal injections in patients with extensive retinal schisis.1
"The favorable safety profile and early efficacy observed in patients treated with ATSN-201 in the low-dose cohort of the LIGHTHOUSE study are very encouraging,” said Kenji Fujita, MD, chief medical officer of Atsena Therapeutics. “We’re particularly pleased to have clinical validation of AAV.SPR’s ability to spread laterally well beyond the subretinal injection blebs.”
According to the news release, XLRS is a monogenic X-linked disease caused by mutations in the RS1gene 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.1
Fujita noted that with dosing of patients in the mid-dose cohort underway, the company is looking forward to the progression of the clinical trial utilizing the company novel spreading capsid and to the continued development of the company’s gene therapy candidate for XLRS patients who currently lack an approved treatment option.
Christine Kay, MD, clinical ophthalmology advisor for Atsena Therapeutics, will present Preliminary safety of ATSN-201 subretinal gene therapy in patients with X-linked retinoschisis at 11:05 am PT May 3 at the Retinal Cell and Gene Therapy Innovation Summit in Seattle.
