Key Takeaways

  • The first patient has undergone subretinal implantation of DSP-3077 in a phase 1/2a study for non-syndromic retinitis pigmentosa
  • The 12-participant study will primarily evaluate the safety and tolerability of 2 dose levels while also assessing engraftment, potential therapeutic response, and delivery-device performance
  • DSP-3077 consists of iPS cell-derived multilayered retinal sheets containing photoreceptor precursors 

Sumitomo Pharma America announced that the first patient has undergone subretinal implantation in a phase 1/2a study evaluating DSP-3077, an investigational regenerative cell therapy for non-syndromic retinitis pigmentosa (RP).

DSP-3077 uses allogeneic retinal sheets derived from induced pluripotent stem (iPS) cells and is designed to provide retinal tissue containing photoreceptor precursors to patients with RP.

The phase 1/2a open-label, single-arm, uncontrolled, dose-escalation study (NCT06891885) is evaluating 2 dose levels of DSP-3077 administered through a single, uniocular subretinal implantation in adults with RP. The study's primary objective is to assess the safety and tolerability of the 2 dose levels. Additional objectives include evaluating safety, engraftment, potential therapeutic response, and the performance of the device used to deliver DSP-3077.

Investigators plan to enroll 12 participants across 3 cohorts, with 4 participants in each cohort. Cohorts will be defined according to visual acuity criteria and DSP-3077 dose level.

“We are encouraged by the potential that iPS cells may hold for treating degenerative, debilitating conditions like RP that currently have few therapeutic options, and this first patient treated is a notable milestone for our company,” said Tsutomu Nakagawa, PhD, president and CEO of Sumitomo Pharma America.

Dr. Nakagawa said treatment of the first study participant represents an important step toward understanding the potential of DSP-3077 and future iPS cell-based therapies for patients with RP.

The technology underlying DSP-3077 is based on a self-organizing cell culture technique known as the "SFEBq method," which is used to generate 3-dimensional neural tissues and organoids from pluripotent stem cells.

According to Sumitomo, the technology was originally developed by Yoshiki Sasai, MD, PhD, and his research group at RIKEN in Japan. Sumitomo Chemical subsequently conducted joint research with RIKEN to further develop the technology, and Sumitomo Pharma later developed a manufacturing process for producing iPS cell-derived retinal sheets.

DSP-3077 is based on a 3-dimensional retinal organoid that is processed into multilayered retinal sheets designed to retain retinal tissue structure and contain abundant photoreceptor precursors. In the phase 1/2a study, these sheets are implanted into the subretinal space.

Sumitomo Pharma America and Sumitomo Pharma are developing DSP-3077 in collaboration with Racthera and S-Racmo as part of ongoing work to advance retinal regenerative therapies.

The FDA granted DSP-3077 Orphan Drug Designation for the treatment of RP in March 2026.