Clearside Biomedical reported positive results from a Phase 2b trial of its tyrosine kinase inhibitor in patients with wet age-related macular degeneration, bolstering its prospects of bringing a different approach to an eye disorder that has been dominated by anti-VEGFs.
In the Phase 2b, Clearside’s CLS-AX injection met the primary endpoint of stable best corrected visual acuity from baseline to 36 weeks in people with wet AMD, according to a Wednesday release.
The company’s shares $CLSD were up by as much as 30% premarket Wednesday.
CLS-AX also met the study’s secondary endpoints, including reducing injection frequency by around 84% over six months compared with the average number of anti-VEGF injections patients had in the 24 weeks prior to screening.
None of the CLS-AX patients needed additional dosing of anti-VEGF drugs at up to 12 weeks. At up to 24 weeks, 67% of the patients didn’t need additional dosing, which is when CLS-AX was redosed.
The eye disorder occurs when abnormal blood vessels grow in the macula in the retina, leading to blurred vision or a blind spot. CLS-AX is a “proprietary suspension” of the TKI axitinib for injection into the area between the sclera and choroid in the back of the eye. Originally developed by Pfizer, axitinib won FDA approval in 2019 to treat renal cell carcinoma with the brand name Inlyta.
Clearside said planning for a Phase 3 study is already underway.
The company believes the pan-VEGF blockade triggered by TKIs could unlock better efficacy versus existing drugs, which tend to target VEGF-A only. VEGF approaches like Regeneron’s Eylea and Novartis’ Lucentis are often administered once every four weeks to begin with and less often after, but CLS-AX is being tested with a less frequent dosing regimen right from the start. The 60-participant Phase 2b used Eylea as an active control.
CLS-AX has the potential “to significantly decrease anti-VEGF treatment burden for patients with wet AMD,” Chardan analysts said in August. The same month, Stifel analysts described the Phase 2b trial design as “thoughtful” because it allows for retreatment with anti-VEGFs, which should “generate more clinically relevant data to guide real-world practice.”
Safety wise, CLS-AX was well-tolerated in the Phase 2b, with no serious adverse events observed and similar discontinuation rates between the treatment and control arms.