Gene Therapies for Blinding Eye Diseases: Clinical Updates and Access for Canadian Patients

March 7th, 2018 by FFB Canada

Now that gene therapy is a reality, there is tremendous growth in the world of gene therapies for blinding eye diseases!

What is a gene therapy? A gene therapy is a new kind of treatment that works by delivering a functioning copy of a gene directly into a patient’s cells. This newly introduced, functioning gene acts as a treatment by replacing a gene that is not working properly. After just a single treatment, gene therapy has the potential to provide lifelong benefits.

Gene therapies are poised to transform healthcare by making personalized medicine possible. Although scientists are working on gene therapies for many different diseases, some of the most rapid growth is in inherited retinal diseases.

Inherited retinal diseases, or IRDs, is a term that is used to describe a diverse, rare group of eye diseases. Each IRD is different, but they all share two common traits: 1) they result in progressive retinal degeneration that leads to severe visual impairment or blindness; and 2) they are “inherited,” which means that they are caused by one or more genetic mutations that are inherited from the DNA we receive from our parents. Today, more than 250 genetic mutations have been identified as causes for IRDs. Some of the more common IRDs include retinitis pigmentosa (RP), Leber congenital amaurosis (LCA), Stargardt disease, choroideremia, Usher syndrome, X-linked retinoschisis (XLRS) and achromatopsia (ACHM).

The chart below highlights ongoing gene therapy clinical trials for IRDs and provides contact information for clinical trials that are accepting Canadian patients. To learn more about the basics of clinical trials and to better understand key terms that are used in the chart (for example, Phase 1 and Phase 2), make sure you read our guide to clinical trials, Everything You Need to Know About Clinical Trials.

ONGOING GENE THERAPY TRIALS FOR INHERITED RETINAL DISEASES (IRDs)

Inherited Retinal Disease (IRD)
Clinical Trial Information (NCT# is the number in clinicaltrials.gov database that can be used to search for additional details)
Contact details for clinical trials that are currently accepting Canadian patients
Leber congenital amaurosis (LCA) is an early-onset disease caused by mutations in any of at least 16 genes.
Multiple clinical trials, funded by different sponsors, have evaluated the safety, tolerability, and efficacy of a single subretinal injection of an AAV vector expressing human RPE65 in patients with LCA2. The first RPE65-based gene therapy received approval in December 2017.
To be determined
MeriaGTx is currently conducting a Phase 1/2 gene therapy clinical trial in LCA2 patients with an RPE65 mutation to evaluate the safety and efficacy of a sub-retinal injection (NCT02781480)
To be determined
X-linked retinoschisis (XLRS) is characterized by schisis (“splitting”) of the retinal layers and reduced visual acuity. XLRS is caused by mutations in the RS1 gene, which encodes the retinoschisin protein.
Two Phase 1/2 clinical trials are currently studying the safety of an intravitreal injection of an AAV vector expressing human RS1 in XLRS patients.
To be determined
Applied Genetic Technologies Corporation (AGTC) is conducting a multicenter, open-label, two-stage dose-escalation trial (NCT02416622).
Applied Genetic Technologies Corporation (AGTC) is enrolling Canadian patients– contact Dr. Jill Dolgin at advocacy@agtc.com to learn more.
The National Eye Institute (NEI) is conducting a single-center, open-label, single-stage dose-escalation trial (NCT02317887).
To be determined
Achromatopsia affects the cone photoreceptors and is characterized by severe sensitivity to light, reduced visual acuity, and loss of colour discrimination. 6 genes are known to cause achromatopsia; about 75% of cases are caused by mutations in either the CNGB3 or CNGA3 genes.
University Hospital Tübingen and Ludwig Maximilian University of Munich are conducting a Phase 1/2 single-center, open-label, single-stage dose-escalation trial for CNGA3 (NCT02610582).
To be determined
AGTC is conducting two, Phase 1/2 multicenter, open-label, two-stage dose-escalation trial for CNGB3 (NCT02599922) and CNGA3 (NCT02935517).
Applied Genetic Technologies Corporation (AGTC) is enrolling Canadian patients – contact Dr. Jill Dolgin at advocacy@agtc.com to learn more.
X-linked retinitis pigmentosa (RP) is the diagnosis of approximately 10-20% of RP cases. More than 70% of X-linked RP cases are caused by mutations in the RPGR gene.
AGTC is conducting a Phase 1/2 multicenter, open-label, two-stage dose-escalation trial to evaluate the safety and tolerability of a subretinal injection of an AAV2 vector expressing human RPGR with a mutation in the ORF15 section of the gene (NCT03316560).
Applied Genetic Technologies Corporation (AGTC) is enrolling Canadian patients – contact Dr. Jill Dolgin at advocacy@agtc.com to learn more.
MeiraGTx is conducting an open-label Phase I/II dose-escalation trial to determine the safety and efficacy of subretinal administration of AAV2 vector expressing RPGR (NCT03252847).
To be determined
Stargardt disease is an inherited macular dystrophy characterized by reduced visual acuity that may begin in late childhood. Stargardt disease is caused by mutations in the ABCA4 gene.
Sanofi is conducting a Phase 1/2 open-label dose-escalation trial (NCT01367444) to evaluate the safety and tolerability of a subretinal injection of a lentiviral vector based on an equine infectious anemia virus (EIAV) expressing human ABCA4 in patients with Stargardt disease.
To be determined
Usher syndrome type 1 is associated with profound deafness and early-onset retinitis pigmentosa. More than half of Usher syndrome cases are type 1B and are caused by mutations in the MYO7A gene.
Sanofi is conducting a Phase 1/2 open-label dose-escalation trial (NCT01505062) to evaluate the safety and tolerability of a subretinal injection of an EIAV-based lentiviral vector expressing human MYO7A.
To be determined
Choroideremia is an X-linked retinal disorder caused by mutations in the CHM gene, which leads to progressive constriction of vision and eventual total blindness.
Six clinical trials, funded by different sponsors, are under way or complete, each evaluating the safety, tolerability, and therapeutic potential of a subretinal injection of an AAV vector expressing human CHM.
To be determined
NightstarX Therapeutics just announced the initiation of the first Phase 3 clinical trial (the STAR trial) to study safety and efficacy in patients with choroideremia.
NightstarX will be enrolling Canadian patients at two different sites in Canada, but the Phase 3 study will not start in Canada until the second half of 2018 (date to be determined); if you live in British Columbia, contact Aleksandra Kuzmanovic, Clinical Research Coordinator, Phone: 604-875-4253
Contact details for the Montreal site will be announced soon
Leber hereditary optic neuropathy (LHON) is associated with central vision loss and characterized by degenerated retinal ganglion cells. More than 90% of cases are caused by mutations in one of three mitochondrial genes—ND1, ND4, and ND6
Two clinical trials are currently enrolling patients, including a Phase 3 multicenter, double-masked, controlled trial by GenSight Biologics (NCT02652780) and a Phase 1 single-center, open-label, dose-escalation trial supported by the NEI and conducted at Bascom Palmer Eye Institute (NCT02161380).
To be determined
Late-stage IRDs when most photoreceptors have been irreparably damaged or lost, regardless of any specific disease-causing mutations.
Optogenetic therapy is an emerging gene therapy-based technology in which light sensitivity is introduced into cells that do not normally detect or respond to light. Current efforts in the retina field are focused on delivering the light-sensitive green algae protein channelrhodopsin 2 (ChR2) intoretinal ganglion cells.
To be determined
RetroSense Therapeutics and the Retina Foundation of the Southwest are conducting a Phase 1/2 single-center, open-label, dose-escalation trial of this therapeutic approach in patients with advanced RP (NCT02556736).
To be determined
AGTC and Bionic Sight are also collaborating to develop a new optogenetic therapy aimed at restoring normal neural signaling in patients with visual deficits or blindness due to retinal disease.
To be determined

This growth in the clinical trials landscape is thanks, in part, to the marvellous, long-term research investments that were made by the FFB here in Canada and by the many other organizations that we collaborate with around the world, including the FFB in the US. And of course, thanks to incredible donors, so much is being done to drive the development of new treatments.

These clinical developments are very exciting, especially for our long-term, deeply committed supporters who have been with us since 1974, when we were first established (read the full story of our history here).

Thanks to our supporters, the FFB helped to fund Canada’s first ocular gene therapy in Edmonton, Alberta under the leadership of Dr. Ian MacDonald. We are passionate about accelerating the development of new treatments, which includes connecting patients to clinical trials that might be a good fit.

If you think that you may be interested in learning more about one of these clinical trials, we encourage you to contact the trial site, to talk with your eye doctor, to seek a second opinion, to reach out to us at the FFB, and to talk with your family. Remember to enroll on the FFB Patient Registry to ensure that you learn about new clinical trial opportunities.

Important tips to remember before searching the clinicaltrials.gov website:

If you search on the website clinicaltrials.gov, you can find many gene therapy clinical trials, and other kinds of trials, that are currently recruiting patients to participate. Searching this website can be a good place to start your research, but we must emphasize that this is just a place to start, not a comprehensive or reliable tool. Unfortunately, many of the trials listed on this website have not been approved by the FDA, which means that they may not meet basic safety and ethics standards. This warning is noted on the clinicaltrials.gov website. We emphasize this warning because research has shown that rogue companies are using the clinicaltrials.gov website to “sell” their unproven “treatments” to patients who are willing to pay almost anything because they hope it might work. Always consult with your doctor before participating in potential trial.

References

Lam, B. 2017. Update on Gene Therapy for the Treatment of Hereditary Retinal Diseases. Retina Today. April, 2017.

Moore, N. et al. 2018. Gene therapy for inherited retinal and optic nerve degenerations. Expert Opinion on Biological Therapy 18: 37-49.

MAKE A DONATION TODAY