Early and Active Interventions: A Substantial Opportunity to Change the Way Diabetic Retinopathy is Treated
Since the 1950s, when diabetic retinopathy (DR) was the leading cause of blindness in the U.S., researchers have developed multiple and varied methods to treat the condition, including laser photocoagulation, intravitreal injections and surgical interventions1. Despite these advancements, the millions of patients living with DR still lack non-invasive therapeutic options. This treatment gap notably affects patients living with the early stages of DR, when ophthalmologists often find that invasive therapies bring more risk than benefit and instead opt to monitor patients without active treatment. As the impact of DR continues to grow and cases are estimated to have reached 10 million in the U.S. alone2, this absence of patient-friendly treatment options becomes more glaring.
Earlier this month, OcuTerra announced a significant achievement – the completion of the last patient’s final visit in its Phase 2 DR:EAM clinical trial. This trial is investigating the safety and efficacy of nesvategrast (OTT166), OcuTerra’s novel, selective integrin inhibitor delivered via eye drop, that is being developed as a non-invasive treatment for DR. If approved, nesvategrast has the potential to shift the paradigm of how the earlier stages of DR are approached and treated. This month, we’re highlighting the significant opportunity for non-invasive therapies to treat millions of patients in the earlier stages of DR, and how these novel interventions are fundamentally different than existing ones.
Patients Only Receive Active Treatment in Later Stages of DR
While there are some active interventions available for the treatment of DR today, these options are unfortunately limited. These treatments are intravitreal anti-VEGF injections and laser photocoagulation, both of which are invasive and associated with the potential for severe side effects or complications, such as scarring and risk of infection3. For anti-VEGF injections, patients will need ongoing treatments indefinitely – usually an initial course of multiple injections every month followed by further injections once every two to four months depending on the severity of disease. In addition, evidence suggests diminishing responses with repeated treatment cycles4.
Because of the associated risks and distressing nature of these procedures, ophthalmologists reserve use for patients in the late stages of DR, once vision has already deteriorated or a specific sight-threatening event, such as diabetic macula edema, has occurred. For those who are initially diagnosed earlier in the course of disease, doctors currently opt for close monitoring to assess the progression of DR. Essentially, patients must endure the progression of the disease affecting their health and quality of life before any proactive intervention is initiated.
DR is a progressive condition – even with lifestyle changes to control blood glucose levels, many patients naturally advance to more severe stages5. Therefore, there is a pressing need for new therapies that allow patients and doctors to take control of DR earlier and move beyond the “watch-and-wait” paradigm.
Active Intervention vs. Watch-and-Wait
“Watch-and-wait” leaves patients with no options to actively manage their disease until more serious complications develop – but what if they were given the option to begin treatment before these complications present, potentially reducing severity in the early stages of disease and slowing or even preventing disease progression?
As DR becomes more severe, vision-threatening complications become increasingly likely6. As patients report the risk of vision loss as one of their top concerns related to DR7, an active therapy that could preserve vision for longer, and potentially even stop disease progression, would be tremendously valuable. The potential benefits of early intervention cannot be overstated, particularly when the only alternative is to do nothing at all.
While the available procedures administered later in DR can be effective at slowing disease progression, they do not reverse it – once visual acuity is lost, it cannot be restored8. In many cases, patients can be diagnosed with early-stage DR without any symptoms or deterioration of their vision – watching and waiting can mean that being symptom-free is only temporary, while active treatment could preserve critical visual health.
The early interventions in development for the treatment of DR are intended to move beyond the standard of care and address fundamentally different aspects of the disease than those used once vision has been impacted. Novel, non-invasive therapies like OcuTerra’s nesvategrast eye drops are under evaluation for their ability to drive improvement on the Diabetic Retinopathy Severity Scale and prevent progression to vision-threatening events or invasive treatment. Rather than addressing existing damage, or waiting for damage to occur, early and active therapies could change the way we think about the progression of DR.
Nesvategrast – A New Candidate Designed for Early Intervention
With the development of nesvategrast, OcuTerra aims to provide an active, non-invasive therapy that brings patients with early-stage DR far beyond the current standard of care. The final patient visit in the DR:EAM clinical trial brings us one step closer to this goal.
OcuTerra has purpose engineered nesvategrast to be administered as an eye drop, a mode of delivery that is regarded as one of the safest and most convenient for ocular drugs9. Topical therapy is patient–friendly in its non–invasive nature and accessibility – eye drops can be self–administered by patients at home on a regular schedule. In addition, nesvategrast is more than an anti-VEGF delivered by an alternative route; it is a selective integrin inhibitor capable of blocking multiple integrin subtypes connected to growth factor signaling, including VEGF, that drive angiogenesis (the growth of new blood vessels), edema (vascular leakage), fibrosis and inflammation.
While nesvategrast is administered through a mode of delivery associated with higher patient compliance compared to injections10, it should not be viewed as an alternative to these fundamentally different interventions. Instead, nesvategrast presents the opportunity to bring patients and their doctors out of “watch-and-wait” through active therapy. With no therapies available for patients in the early stages of DR, the benefits of delaying or preventing vision-threatening complications can’t be overstated.
Topline data from the DR:EAM study are expected in the first quarter of 2024 and will detail the safety and efficacy of nesvategrast in 225 patients with moderately severe to severe non-proliferative diabetic retinopathy (NPDR) or mild proliferative diabetic retinopathy (PDR) with minimal vision loss. There is a tremendous opportunity to change the way we think about this progressive disease, and the OcuTerra team is incredibly motivated by the potential to transform the standard of care for DR. As we prepare for the next phase of nesvategrast’s development, we are appreciative of our substantial opportunity to make a difference for patients and their families.
References
Mansour, S. E., Browning, D. J., Wong, K., Flynn, H. W., & Bhavsar, A. R. (2020). The Evolving Treatment of Diabetic Retinopathy. Clinical Ophthalmology, 14, 653–678. https://doi.org/10.2147/OPTH.S236637
Lundeen, E. A., Burke-Conte, Z., Rein, D. B., Wittenborn, J. S., Saaddine, J., Lee, A. Y., & Flaxman, A. D. (2023). Prevalence of diabetic retinopathy in the US in 2021. JAMA Ophthalmology, 141(8), 747–754. https://doi.org/10.1001/jamaophthalmol.2023.2289
Gupta, N., Mansoor, S., Sharma, A., Sapkal, A., Sheth, J., Falatoonzadeh, P., Kuppermann, B., & Kenney, M. (2013). Diabetic retinopathy and VEGF. The open ophthalmology journal, 7, 4–10. https://doi.org/10.2174/1874364101307010004
Yang, S., Zhao, J., & Sun, X. (2016). Resistance to anti-VEGF therapy in neovascular age-related macular degeneration: a comprehensive review. Drug design, development and therapy, 10, 1857–1867. https://doi.org/10.2147/DDDT.S97653
Moshfeghi A., et al. Five-Year Patterns of Diabetic Retinopathy Progression in US Clinical Practice. Clinical Ophthalmology 2020:14 3651–3659
Maturi, RK., et al. Four Year Visual Outcomes of Protocol W. Suppl 3 Fig 3. JAMA Ophthalmology 2023;329(5): 376-385
Coyne, K. S., Margolis, M. K., Kennedy-Martin, T., Baker, T. M., Klein, R., Paul, M. D., & Revicki, D. A. (2004). The impact of diabetic retinopathy: Perspectives from patient focus groups. Family Practice, 21(4), 447–453. https://doi.org/10.1093/fampra/cmh417
NIH. (n.d.). Diabetic Retinopathy. National Eye Institute. https://www.nei.nih.gov/learn-about-eye-health/eye-conditions-and-diseases/diabetic-retinopathy
Gaudana, R., Ananthula, H. K., Parenky, A., & Mitra, A. K. (2010). Ocular drug delivery. The AAPS journal, 12(3), 348–360. https://doi.org/10.1208/s12248-010-9183-3
Jacobs, B., Palmer, N., Shetty, T., Dimaras, H., Hajrasouliha, A., Jusufbegovic, D., & Corson, T.W. (2021) Patient preferences in retinal drug delivery. Scientific reports, 11(1), 7-8. https://doi.org/10.1038/s41598-021-98568-7