US-based Clearside Biomedical announced plans for a Phase IIb trial investigating CLS-AX (axitinib) in patients with neovascular age-related macular degeneration (wet AMD). The trial will start enrolling in multiple US-based clinical trial sites in Q2 2023, with topline results expected in Q3 2024.

The randomised, double-masked, active-controlled trial will enrol 60 treatment-experienced participants with wet AMD. A total of 40 participants will be randomised into the CLS-AX arm while 20 will be assigned to the aflibercept arm, which is the current standard of care.

The primary endpoint will measure the mean change in best corrected visual acuity (BCVA) from baseline to week 36. Secondary endpoints will look at other changes in visual function and ocular anatomy, the need for supplemental treatment, and treatment burned measured by total injections during the trial.

In the loading dose stage, participants in both arms will receive three 2mg aflibercept doses. In the treatment arm, participants with receive one 1mg dose of CLS-AX at the same visit as the second loading dose of the active comparator. CLS-AX is an injectable suspension of a tyrosine kinase inhibitor.

After receiving the three loading doses of the comparator, CLS-AX arm participants will receive the investigational drug at least every 24 weeks unless more frequent dosing is needed based on the disease activity.

In the active comparator arms, participants with receive aflibercept every eight weeks. All participants will be assessed on weeks 12 through 32 to determine if supplemental treatment is needed.

Clearside and AMD drug development

Last year, Clearside investigated CLS-AX in an open-label Phase I/IIa trial. The three-month trial was followed up by a three-month extension study where 14 of the participants were monitored for further six months after receiving a single dose of CLS-AX.

CLS-AX met the primary endpoint of the Phase I/IIa trial, demonstrating a safety profile at all doses and time points. Two of the four cohorts showed signs of durability, biological effect, and a meaningful reduction in treatment burden.

In October 2021, Clearside’s lead ophthalmology candidate Xipere (triamcinolone acetonide injectable suspension) gained FDA approval for the treatment of macular oedema associated with uveitis.

A progressive loss of central vision, AMD is the most common cause of legal blindness in people over the age of 55. There are two types of AMD: dry and wet AMD, with the latter leading to quicker loss of vision. As previously reported by Clinical Trials Arena, the number of wet AMD trials surpasses dry AMD trials substantially.

Earlier this year, FDA’s CDER released a draft guidance on developing drugs for the treatment of wet AMD as part of its 2023 draft guidance agenda. Sponsors and other industry stakeholders can submit their comments until late May 2023.