- MeiraGTx and partner Johnson & Johnson on Friday reported the first results for an experimental gene therapy for X-linked retinitis pigmentosa, one of three clinical-stage treatments to come from a 2019 alliance between the two companies.
- Five of seven patients given a low or medium dose of the gene therapy had meaningful improvements in retinal sensitivity after six months, suggesting the treatment could potentially help slow or stabilize the progressive vision loss caused by the disease. MeiraGTx and J&J plan to advance the program into a Phase 3 trial.
- The gene therapy is one of several in development for XLRP, a disease with no effective treatment that often leads to blindness. A treatment from Biogen is in late-stage testing, while another from Florida biotech AGTC is in a Phase 1/2 trial.
Thus far, Johnson & Johnson has not been a major player in gene therapy. Fellow large pharmas Roche, Novartis and Pfizer have each made more sizable bets, while biotechs like Bluebird bio, Sarepta and BioMarin have amassed pipelines of gene-based treatments, some of which are nearing regulatory approvals in the U.S.
Still, J&J has signaled some interest in gene therapy through partnerships, the most notable of which is its 2019 alliance with MeiraGTx. The $440 million pact gave J&J rights to a portfolio of treatments the biotech is developing for inherited retinal diseases.
The gene therapy reported on Friday at the annual meeting of the American Society of Retinal Specialists is one of those treatments and, given the results, likely the first that will be headed to late-stage testing.
Retinitis pigmentosa describes a group of diseases in which the light-sensing photoreceptor cells in the back of the eye deteriorate, leading to vision loss and potentially total blindness. The X-linked form, which mainly affects boys, is particularly severe and accounts for some 10% to 20% of cases. Visual deterioration typically begins in childhood, progressing to legal blindness at a median age of 45 years. A majority of those cases are caused by mutations to the RPGR gene.
No treatments are available to help stop the erosion of vision in XLRP patients. But the programs from Biogen — acquired via its $800 million buyout of Nightstar Therapeutics — and AGTC could change that, showing encouraging early results.
These therapies deliver a functional form of the RGPR gene into the eye, which then produces proteins meant to prevent photoreceptors from degenerating. So far, both of those gene therapies have shown an ability to increase retinal sensitivity in some, but not all patients.
Results published in Nature Medicine earlier this year, for instance, showed six of 18 patients injected with Biogen's gene therapy in an early-stage trial had improved ability in peripheral vision — what's known as the visual field — six months after treatment.
MeiraGTx and J&J, meanwhile, enrolled into their study 10 adults with XLRP caused by an RGPR mutation and delivered the gene therapy into one eye, with each patient's other eye serving as a control. The trial's goal was to show treatment is safe and to pick the best dose for further testing.
Five of the seven patients who received a low or medium dose had a meaningful improvement in multiple evaluations of retinal sensitivity six months after treatment. Signs of effectiveness were seen after three months, and either held up or improved with more follow-up.
In two of three patients given a high dose, however, the companies observed evidence of inflammation that they said contributed to "decreased activity" of the gene therapy. The inflammation, which wasn't seen at the lower doses, was managed with a course of steroids.
"The data look promising since they report improvement in retinal sensitivity across the visual field," Sherry Bass, a professor at SUNY College of Optometry in New York and a retinal disease researcher who isn't involved in the trial, wrote in an email to BioPharma Dive. XLRP patients lose their peripheral vision early in life, "so this is an exciting finding," she said.
Trial investigator Michel Michaelides, a professor of ophthalmology at University College London, said that the results show the gene therapy has "the potential to stabilize or slow progressive vision loss." More follow-up will be needed to bear that out, however.
The two companies aim to advance the treatment into a Phase 3 trial called Lumeos. Two other gene therapies from the pact, for forms of achromatopsia, or color blindness, are in Phase 1 testing.
MeiraGTx shares ticked up about 7% in early trading.