On this episode of Retina Mentor Moments, John W. Kitchens, MD, is joined by Peter K. Kaiser, MD, to discuss the ins and outs of drug development for retinal diseases and recent advancements in the retina pipeline.
Dr. Kaiser is the Chaney Family Endowed Chair of Ophthalmology Research and Professor of Ophthalmology at the Cleveland Clinic Lerner College of Medicine, and a consulting surgeon in the vitreoretinal department at the Cole Eye Institute, Cleveland Clinic in Cleveland, Ohio.
Finding your niche in academic retina spaces
After completing a vitreoretinal fellowship at the Bascom Palmer Eye Institute, Dr. Kaiser was one of the first retina specialists to join the newly established Cole Eye Institute after he was recruited by Hilel Lewis, MD, the then Chair, who helped build and develop the now preeminent ophthalmologic institution.
He explained that over the course of his career, he has had the privilege of working under incredible chairpersons and even considered taking on the role of chair himself. However, he recognized that a great chairperson prioritizes promoting the institution and faculty over their individual research, and his passion for drug development created a conflict between being a great chairman and finding happiness and fulfillment in his career.
The path to drug development
When Dr. Kaiser first started at Cole, optical coherence tomography (OCT) technology was in its infancy, with many ophthalmologists at the time believing that it would “never amount to anything” due to its perceived limited clinical utility. However, the PrONTO Study proved that a variable dosing regimen of ranibizumab guided by OCT resulted in similar outcomes to fixed dosing schedules, but with fewer doses required.1,2
Following the results of this study, Dr. Kaiser believed that OCT would revolutionize retina care by allowing for personalized treatments, which led him to founding the OCT Reading Center at Cole, and eventually working more closely with biopharmaceutical companies. This ultimately led him to finding his niche in drug development through a mix of luck and persistence.
He added that some of the key skills required to excel in drug development include:
- Chemistry, manufacturing, and controls (CMC) management
- Interpreting preclinical and clinical data
- Designing clinical studies for Regulatory Approval
To hear more insights into getting involved in drug development and the process of working with the FDA, watch the full interview!
Working with the Chinese government to develop conbercept
Dr. Kaiser was involved in the development and subsequent approval of conbercept (Lumitin, Chengdu Kanghong Biotech) for the treatment of wet age-related macular degeneration (AMD) in China. Conbercept is a recombinant fusion protein that exhibits a higher affinity to vascular endothelial growth factor (VEGF) than ranibizumab and bevacizumab, but is similar to aflibercept, due to the addition of the fourth Ig-like domain of VEGFR-2 in the Fab fragment.3
He recounted a story in which he was in a meeting (alongside a translator) with the head of the China Food and Drug Administration (now the National Medical Products Administration) and representatives from Chengdu Kanghong Biotech, where he was asked how long a clinical study needs to be to determine the treatment effect of an anti-VEGF drug.
He responded that you tend to see the efficacy of an anti-VEGF agent in around 3 months, because after that point, the dose-response curves tend to flatten out. Unbeknownst to him, this paved the way for conbercept’s clinical study to assess primary outcomes at 3 months (instead of the usual 1-year duration).
He added that conbercept has performed well in China, and he found working with the Chinese government fun because there was a sense of national pride in developing the drug in the country from phase 1 through approval.
Retina pipeline advancements: AXPAXLI (OTX-TKI)
Last year, Dr. Kaiser joined Ocular Therapeutix as the Chief Development Officer to help develop AXPAXLI ([OTX-TKI] intravitreal axitinib implant, Ocular Therapeutix), which is a bioresorbable hydrogel intravitreal implant that continuously delivers axitinib—an FDA-approved small-molecule, multi-target tyrosine kinase inhibitor (TKI).4
The implant is placed using a 25G needle with a 9- to 12-month target release via the company’s proprietary and patented ELUTYX technology platform, which is reportedly tunable for use in various locations within the eye to maximize therapeutic efficacy while minimizing systemic exposure.4
AXPAXLI is being investigated for the following indications:4
- Non-proliferative diabetic retinopathy (NPDR), including diabetic macular edema (DME)
- Wet AMD
- Other VEGF-mediated retinal diseases
For its NPDR indication, positive 48-week data were reported from the phase 1 HELIOS trial (NCT05695417) at the 2025 ARVO Annual Meeting, wherein:5,6
- AXPAXLI was found to be well-tolerated
- None of the patients in the AXPAXLI cohort experienced any worsening Diabetic Retinopathy Severity Scale (DRSS)
- A single injection of AXPAXLI provided durable DRSS improvement up to 1 year, with all patients stable or improved
- In contrast, none of the sham patients improved their DRSS score
- Benefits were also seen in terms of retinal thickness, total retinal volume, and total retinal vascular leakage in all AXPAXLI patients, and none of the sham patients
Next, for the wet AMD indication, AXPAXLI is currently under evaluation in the phase 3 SOL-1 (NCT06223958) and SOL-R (NCT06495918) studies. The topline data is expected by Q1 2026 for SOL-1 and H1 2027 for SOL-R, with the goal of enabling dosing every 6 to 12 months.4 Dr. Kaiser explained that he hopes AXPAXLI will make a significant difference in reducing treatment burden while enhancing efficacy for patients with VEGF-mediated retinal diseases.
To learn more about the data from the phase 1 study (NCT04989699) on AXPAXLI for wet AMD, check out Ocular Therapeutix releases 12-month topline data from phase 1 wet AMD trial!
Conclusion
Dr. Kaiser’s career reflects the lasting impact of technological and pharmaceutical advancements in retina care, from OCT to anti-VEGF agents to sustained-release treatments, that continuously reduce treatment burden on patients and improve outcomes for retinal diseases.
