Viridian poised to challenge Horizon in thyroid eye disease

Eye, check up

Viridian poised to challenge Horizon in thyroid eye disease

Published: Jul 11, 2023

By Tristan Manalac


Preliminary findings from a small Phase I/II study showed that Viridian Therapeutics’ investigational antibody VRDN-001 induces rapid and clinically meaningful improvements in the signs and symptoms of thyroid eye disease, the company announced Monday.

After six weeks of treatment, patients who were given the 10-mg/kg dose of VRDN-001 saw a 1.8-mm decrease in proptosis, which refers to the eye’s abnormal protrusion and is a major hallmark of thyroid eye disease (TED). Meanwhile, the lower 3-mg/kg dose induced a 1.5-mm reduction in proptosis.

These early-stage clinical efficacy data for VRDN-001 come on the heels of Horizon’s Phase IV Tepezza (teprotumumab-trbw) findings, which was approved in January 2020 for TED. In April 2023, the Irish biotech released post-approval performance data showing that Tepezza reduced proptosis by around 2.4 mm after 24 weeks of treatment.

Meanwhile, Tepezza’s label indicates a proptosis decrease of 2.5 mm to 2.8 mm after 24 weeks, according to two studies that contributed to its approval.

As with all cross-trial comparisons, however, definitive conclusions about relative efficacies cannot be drawn without direct, head-to-head studies. This is even more true due to crucial differences between Horizon’s and Viridian’s trials, including study phase, sample size and various patient characteristics.

In their studies, Viridian and Horizon measured proptosis using exophthalmometry, the most common technique used to assess the eyeball’s position. Viridian, however, also employed magnetic resonance imaging to evaluate eye protrusion.

Using this method, Viridian found a greater therapeutic potential to the 3-mg/kg, which reduced proptosis by 2.6 mm, as opposed to the higher 10-mg/kg dose, which only improved proptosis by 1.5 mm. The company also assessed the clinical activity score and found that both doses reduced patients’ scores by approximately two points on a seven-point scale.

In terms of safety, VRDN-001 did not induce any serious adverse events. Viridian also did not document any cases of hyperglycemic events or hearing impairments.

“Thus far, these data suggest that VRDN-001 has the potential to become an important new treatment option for managing the signs and symptoms of TED,” Kimberly Cockerham, investigator on the VRDN-001 trial, said in a statement. Cockerham is also an oculoplastic surgeon at the SENTA Clinic in San Diego, California.

Along with these early-stage data, Viridian on Monday announced amendments to its ongoing Phase III THRIVE study of VRDN-001. After discussions with the FDA—as well as with key stakeholders from the TED community—the company will now evaluate a shortened five-dose regimen of the candidate, instead of the originally planned eight-dose schedule. Topline data from THRIVE are expected by mid-2024.

Viridian is now also planning a second Phase III trial, THRIVE-2, to evaluate the safety and efficacy of VRDN-001 in chronic TED. This study is expected to begin in the third quarter of 2023 with early data by the end of next year.