After making the correct diagnosis, the patient can participate in several types of therapeutic treatments and clinical trials. There are several ongoing and completed trials for treating retinitis pigmentosa with gene therapy, drugs, oxygen therapy, stem cell transplantation and even acupuncture, that can be found on ClinicalTrials.gov. For instance, in a study performed by Rubens C. Siqueira, patients with severe retinitis pigmentosa were treated with an “intravitreal injection of autologous bone marrow stem cells” and evaluated monthly for an entire year with OCT and ERG. Results revealed a “1-line improvement in best-corrected visual acuity was measured in 4 patients 1 week after injection and was maintained throughout follow-up” and no detectable ERG responses. They concluded that since there were no adverse/toxic effects, it would be probable to conduct and investigate more types of autologous bone marrow-derived mononuclear cell therapies (Siqueira, 2011).
In another 2011 study, a RHO suppression and RHO replacement gene therapy was administered on a mouse model (P347S) with RHO-linked autosomal dominant retinitis pigmentosa. Both 5-day-old and adult mice were injected with adeno-associated virus (AAV) vectors that were used to “deliver an RNA interference (RNAi)-based rhodopsin suppressor and a codon-modified rhodopsin replacement gene resistant to suppression due to nucleotide alterations at degenerate positions over the RNAi target site” (Millington, 2011). By suppressing and replacing the mutated photoreceptors, the researchers predicted that they should function similarly to wild-type photoreceptors. They found that the ONL completely disappeared in untreated mice (the control group with the disease) and mice that were treated rhodopsin was expressed in the ONL. ERG comparisons between both groups showed significant improved responses when both types of vectors were administered. They also concluded that this type of approach can possibly pertain to any patient with RHO-linked regardless of the mode of action of a particular RHO mutation in future clinical studies (Millington, 2011). Consequently, retinitis pigmentosa is uncurable, however it seems that gene therapy could provide some type of solution.
Siqueira, R C, et al. “Intravitreal Injection of Autologous Bone Marrow-Derived Mononuclear Cells for Hereditary Retinal Dystrophy: a Phase I Trial.” Retina (Philadelphia, Pa.)., U.S. National Library of Medicine, 31 June 2011, www.ncbi.nlm.nih.gov/pubmed/21293313?dopt=Abstract.
Millington-Ward, Sophia, et al. “Suppression and Replacement Gene Therapy for Autosomal Dominant Disease in a Murine Model of Dominant Retinitis Pigmentosa.” Molecular Therapy, vol. 19, no. 4, 11 Jan. 2011, pp. 642–649. NCBI, doi:10.1038/mt.2010.293.