Sumitomo Pharma America said the first participant in a phase 1/2a study of DSP-3077 for nonsyndromic retinitis pigmentosa (RP) has undergone subretinal implantation of the investigational cell therapy. DSP-3077 consists of an allogeneic retinal sheet containing photoreceptor precursors that is derived from induced pluripotent stem cells.

The open-label, single-arm, uncontrolled, dose-escalation trial is evaluating 2 dose levels in adults with RP. Twelve participants will be enrolled in 3 cohorts, with cohorts defined by visual acuity criteria and dose level, and DSP-3077 will be administered once to the study eye. The primary objective is to assess safety and tolerability; additional objectives include evaluating engraftment, potential therapeutic response, and performance of the delivery device.

DSP-3077 is manufactured from a 3-dimensional retinal organoid generated through a self-organizing cell culture method and processed into multilayered retinal sheets containing photoreceptor precursors. The underlying technology originated with Dr. Yoshiki Sasai’s research group at Riken, Japan's leading national comprehensive research institute, and was subsequently developed for clinical use by Sumitomo Pharma and its research partners. The US Food and Drug Administration (FDA) granted DSP-3077 orphan drug designation for RP in March 2026.