Viridian Therapeutics’ phase 3 thyroid eye disease (TED) clinical trial has hit its primary and secondary endpoints. But with Amgen’s Tepezza already on the market, the data leave scope to question whether the biotech has done enough to differentiate its asset and unseat the incumbent.
Massachusetts-based Viridian exited phase 2 with six-week data showing its anti-IGF-1R antibody looked as good or better than Tepezza on key endpoints, encouraging the biotech to advance into phase 3. The study compared the drug candidate, which is called both veligrotug and VRDN-001, to placebo. But the presence of Tepezza on the market meant Viridian would need to do more than just beat the control to secure a shot at significant market share.
Here’s how the comparison to Tepezza shakes out. Viridian said 70% of recipients of veligrotug had at least a 2 mm reduction in proptosis, the medical term for bulging eyes, after receiving five infusions of the drug candidate over 15 weeks. Tepezza achieved (PDF) response rates of 71% and 83% at week 24 in its two clinical trials. The placebo-adjusted response rate in the veligrotug trial, 64%, fell between the rates seen in the Tepezza studies, 51% and 73%.
The second Tepezza study reported a 2.06 mm placebo-adjusted change in proptosis after 12 weeks that increased to 2.67 mm by week 18. Viridian saw a 2.4 mm placebo-adjusted change after 15 weeks.
There is a clearer separation on a secondary endpoint, with the caveat that cross-trial comparisons can be unreliable. Viridian reported the complete resolution of diplopia, the medical term for double vision, in 54% of patients on veligrotug and 12% of their peers in the placebo group. The 43% placebo-adjusted resolution rate tops the 28% figure seen across the two Tepezza studies.
Safety and tolerability offer another opportunity to differentiate veligrotug. Viridian is yet to share all the data but did report a 5.5% placebo-adjusted rate of hearing impairment events. The figure is lower than the 10% seen in the Tepezza studies but the difference was driven by the rate in the placebo arm. The proportion of events in the veligrotug arm, 16%, was higher than in the Tepezza studies, 10%.
Viridian expects to have top-line data from a second study by the end of the year, putting it on track to file for approval in the second half of 2025. Investors sent the biotech’s share price up 13% to above $16 in premarket trading Tuesday morning.
The questions about how competitive veligrotug will be could get louder if the other companies that are gunning for Tepezza deliver strong data. Argenx is running a phase 3 trial of FcRn inhibitor efgartigimod in TED. And Roche is evaluating its anti-1L-6R satralizumab in a pair of phase 3 trials. Viridian has its own plans to improve on veligrotug, with a half-life-extended formulation now in late-phase development.