PurposeTo evaluate the feasibility and safety of intravitreal injection of autologous CD34+ stem cells from bone marrow (BMSCs) in eyes with vision loss from retinitis pigmentosa (RP). DesignPhase I prospective open-labeled single center study. ParticipantsSeven eyes (7 patients) with RP with best corrected visual acuity (BCVA) of 20/100 to 20/400 or visual field constriction to within 10 degrees. MethodsA comprehensive exam with ETDRS BCVA, macular optical coherence tomography, perimetry, fluorescein angiography was performed at baseline, 1 to 3 months, and 6 months after study treatment. Bone marrow aspiration, isolation of CD34+ BMSCs under Good Manufacturing Practice (GMP) conditions, and intravitreal cell injection were performed on the same day. The CD34+ cells were isolated from bone marrow using a Ficoll gradient and the Miltenyi CliniMACs system. Isolated CD34+ cells were released for clinical use if viability, sterility and purity met the release criteria accepted by the Food and Drug Administration for this clinical study. Main Outcome MeasuresNumber of CD34+ cells isolated for injection and adverse events associated with study treatment during follow-up. Secondary outcome measures are changes in BCVA and perimetry. ResultsAll isolated CD34+ cells passed the release criteria. A mean of 3.26 + 0.66 million viable CD34+ cells (range 1.6 to 7.05 million) were injected intravitreally per eye. No adverse event was noted during the study follow-up except for one participant who was noted with transient cells in the anterior chamber with mild elevation in intraocular pressure at 18 hours after study injection which normalized by 24 hours. BCVA remained within 2 lines of baseline or improved in all participants at 6 months follow-up. Perimetry was stable or improved in all eyes during study follow-up except one eye with transient improvement at 1 month and worsening of both eyes at 6 months. ConclusionIntravitreal injection of autologous CD34+ BMSCs is feasible and appears to be well tolerated in eyes with vision loss from RP. A larger randomized prospective study would be needed to evaluate further the safety and potential efficacy of this cell therapy for vision loss associated with RP.
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