• GS030 is safe and well tolerated for at least 1 year after injection at all tested doses
  • Encouraging efficacy signals observed in some patients
  • Ongoing recruitment of GS030 extension cohort at the highest dose of 5e11 vg per eye

Paris, France, February 13, 2023, 7:30 am CET – GenSight Biologics (Euronext: SIGHT, ISIN: FR0013183985, PEA-PME eligible), a biopharma company focused on developing and commercializing innovative gene therapies for retinal neurodegenerative diseases and central nervous system disorders, today announced favorable safety data and encouraging efficacy signals at 1 year post-gene therapy administration for the PIONEER Phase I/II clinical trial evaluating GS030 for the treatment of retinitis pigmentosa (RP) in 9 patients, with a follow-up up to 4 years (n=1).


“While the primary endpoint of the study is safety and tolerability at 1 year after gene therapy administration, we have patients that are followed much longer and have already reached 3 and even 4 years post-injection, which continue to show good tolerability and safety,” commented Élise Boulanger-Scemama, MD, Adolphe de Rothschild Foundation Hospital, Clinical Investigation Center CHNO des 15-20 and investigator of PIONEER. “Those results for GS030 are particularly encouraging and could bring back hope for patients suffering from end-stage RP with currently no therapeutic solution.”

RP is a genetic blinding disease that affects between 15,000 and 20,000 new patients each year in the US and the EU for which there is currently no treatment. PIONEER is a first-in-human, multi-center, open-label dose escalation clinical trial evaluating the safety and tolerability of GS030, an optogenetic treatment candidate combining an AAV2-based gene therapy (GS030-DP) with the use of light-stimulating goggles (GS030-MD) in patients with end-stage RP. This therapeutic approach is independent of the causal mutation and therefore applicable to potentially all patients suffering from end-stage RP.


Three cohorts of three patients each were administered one of three doses of GS030-DP (5e10 vg; 1.5e11 vg; 5e11 vg) via a single intravitreal injection in their worst affected eye (i.e., the least-seeing eye). A Data Safety Monitoring Board (DSMB) reviewed the safety data of all treated subjects in each cohort and made recommendations before the extension cohort was enrolled. Based on the good safety profile of GS030, the DSMB recommended selecting the highest dose (5e11 vg) for the extension cohort where patients are currently being recruited.


The safety and tolerability results in the first three completed cohorts recorded only mild and moderate (grade 1 and 2) ocular adverse events (AEs) but no severe (grade 3) AEs, with a follow-up up to 4 years (n=1). The most common ocular AEs were mild intraocular inflammation responsive to corticosteroid treatment. Intraocular inflammation occurred in 70% of patients and resolved without sequalae in all patients.

The first use of GS030-MD was performed 8 weeks after injection under medical supervision and the light-stimulating goggles were well tolerated. Subjects performed multiple training sessions in parallel to scheduled study visits.


The patients from the highest dose cohort have reached 1-year post-gene therapy administration, enabling the assessment of efficacy signals at one year for the 3 cohorts. Encouraging signs of efficacy at 1 year were demonstrated in some patients after GS030 optogenetic treatment with a vision that improved from being barely able to perceive light before treatment to being able to locate and count objects, with the best results at the highest dose.

“Retinitis pigmentosa is the most frequent blinding genetic disorder for which there is currently no treatment. The safety data and early efficacy signals from our PIONEER trial are highly encouraging and suggest that our optogenetic treatment candidate could offer hope to the many patients affected,” said Bernard Gilly, Co-Founder and Chief Executive Officer of GenSight Biologics. ” We are looking forward to further data from the extension cohort that is under recruitment and expect then to move GS030 to efficacy trials.”