MARLBOROUGH, Mass., August 12, 2026
Sumitomo Pharma America, Inc. announced that the first patient has received treatment with DSP-3077 in a Phase 1/2a clinical study evaluating the investigational therapy for non-syndromic retinitis pigmentosa (RP). DSP-3077 is an allogeneic induced pluripotent stem cell (iPS cell)-derived retinal sheet, representing a regenerative cell therapy designed to replace or support damaged retinal tissue. The treatment is administered through a single subretinal injection in one eye. The open-label, single-arm, dose-escalation study is evaluating the safety and tolerability of two DSP-3077 dose levels, while also assessing retinal cell engraftment, potential therapeutic response and delivery-device performance. The study is expected to enroll 12 adult participants across three cohorts, with four participants in each cohort. The first-patient treatment represents an important clinical development milestone for Sumitomo Pharma’s retinal regenerative medicine program.
DSP-3077 Uses iPS Cell-Derived Retinal Tissue
DSP-3077 is based on a three-dimensional retinal tissue generated from pluripotent stem cells using a self-organizing cell culture technology. The resulting 3D retinal organoid is processed into multilayered retinal sheets containing retinal tissue structures and photoreceptor precursors. The approach is intended to address retinal degeneration by introducing functional retinal tissue into the subretinal space. The underlying technology originates from research conducted by RIKEN and subsequently advanced through collaborative research involving Sumitomo Chemical and Sumitomo Pharma. Sumitomo Pharma and its affiliated organizations have continued development of manufacturing and research capabilities designed to support the potential clinical application of iPS cell-derived retinal therapies. DSP-3077 has received FDA Orphan Drug Designation for retinitis pigmentosa, granted in March 2026, providing regulatory recognition for its development in this rare inherited eye disorder.
Phase 1/2a Study Evaluates Safety and Engraftment
The Phase 1/2a study (NCT06891885) is designed primarily to evaluate the safety and tolerability of DSP-3077 following subretinal implantation. Additional objectives include evaluating whether the transplanted retinal sheets can successfully engraft within the eye, assessing potential changes in visual function and characterizing the performance of the delivery system. Participants will receive treatment according to visual-acuity criteria and assigned dose levels. Because this is an early-stage, open-label and uncontrolled study, its primary purpose is to establish initial clinical safety and generate preliminary evidence of biological and therapeutic activity rather than demonstrate definitive efficacy. Positive safety, engraftment and functional findings could support further development, while longer-term follow-up will be necessary to determine whether the therapy can meaningfully preserve or improve vision in patients with RP.
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Sumitomo Pharma Targets Major Unmet Need in RP
Retinitis pigmentosa is a group of inherited retinal disorders characterized by progressive degeneration of photoreceptor cells and gradual loss of vision. The condition commonly begins with impaired night vision and peripheral vision before potentially progressing to central vision loss. RP affects approximately one in 4,000 people and currently has limited treatment options, creating a significant unmet medical need for regenerative approaches. DSP-3077 represents an effort to address the underlying retinal cell loss rather than simply managing symptoms. The first patient treatment marks the transition of this iPS cell-derived retinal regenerative therapy into clinical evaluation in RP. Further results from the Phase 1/2a program will be important in determining whether DSP-3077 can demonstrate an acceptable safety profile, successful retinal engraftment and signals of visual benefit. If these objectives are achieved, the program could provide a foundation for larger clinical studies of cell-based retinal regeneration and potentially expand the role of iPS cell technology in treating degenerative eye diseases.
Source:Bone Sumitomo Pharma America press release
