Atsena Therapeutics has received EMA orphan designation for two gene therapies targeting inherited retinal diseases, as both programmes advance towards pivotal Phase 3 trials.

Atsena Therapeutics has received orphan designation from the European Medicines Agency (EMA) for its two clinical-stage gene therapy candidates, ATSN-101 and ATSN-201, which are being developed for rare inherited retinal diseases.

ATSN-101 is being developed for GUCY2D-associated Leber congenital amaurosis type 1 (LCA1), while ATSN-201 is being evaluated for X-linked retinoschisis (XLRS).

The EMA orphan designation applies to medicines intended to treat, diagnose or prevent rare, life-threatening or chronically debilitating conditions. The designation can provide developers with regulatory and development benefits, including reduced regulatory fees, clinical protocol assistance and research grants, as well as market exclusivity in the European Union following approval.

Patrick Ritschel, chief executive officer of Atsena, said: “Receiving orphan designation from the EMA for both ATSN-101 and ATSN-201 underscores that these programs address significant unmet needs for patients who currently have no treatment options.”

The two programmes are at different stages of clinical development.

Atsena dosed the first patient in the pivotal Phase 3 cohort of its LIGHTHOUSE trial evaluating ATSN-201 in June 2026. The company said enrolment is progressing, with sites in the US currently recruiting and additional sites in Europe and the UK expected to open later this year.

The pivotal Phase 3 portion of the LIGHTHOUSE trial is a randomised, controlled study expected to enrol approximately 76 patients aged six years and older. The primary endpoint is microperimetry, with a primary readout planned at 52 weeks.

ATSN-201 is an investigational gene therapy designed to treat XLRS, a genetic eye disease caused by mutations in the RS1 gene. The condition primarily affects males and is usually diagnosed in childhood, with progressive vision loss that can ultimately lead to blindness.

There are currently no approved disease-specific treatments for XLRS.

Atsena said earlier Phase 1/2 data for ATSN-201 showed improvements in retinal structure and visual function in the majority of patients treated. The company also reported that the therapy had been well tolerated, with follow-up data extending to two years in some patients.

The second programme, ATSN-101, is being developed for LCA1, a rare inherited retinal disease caused by mutations in the GUCY2D gene. The condition can cause severe vision impairment or blindness from an early age and currently has no approved treatments.

ATSN-101 has completed a Phase 1/2 clinical trial, with Atsena reporting durable improvements in vision at 36 months following treatment with the high dose. The company said no drug-related serious adverse events were reported.

Atsena expects to begin a global pivotal Phase 3 clinical trial evaluating ATSN-101 in the second half of 2026, with sites planned across the US, Europe and Japan.

The programme is being developed through a strategic collaboration with Nippon Shinyaku Co Ltd. Nippon Shinyaku holds exclusive rights to ATSN-101 in the US and Japan, while Atsena retains rights in other territories.

Both ATSN-101 and ATSN-201 have previously received Orphan Drug, Rare Pediatric Disease, Fast Track and Regenerative Medicine Advanced Therapy designations from the US Food and Drug Administration (FDA).

The EMA orphan designations add European regulatory recognition for the two programmes as Atsena prepares to advance both candidates through pivotal-stage clinical development.

The company is also developing gene therapies for Usher syndrome type 1B and Stargardt disease as part of its broader pipeline targeting inherited retinal diseases and vision loss.