Teprotumumab improves proptosis, quality of life for adults with thyroid eye disease
Adults with thyroid eye disease assigned the human monoclonal antibody teprotumumab were significantly more likely to experience a meaningful improvement in proptosis after 21 weeks of treatment compared with those who received placebo, according to findings from a randomized controlled trial published in The New England Journal of Medicine.
“Other than highly invasive surgical procedures, patients with thyroid eye disease had no real treatment alternatives,” Raymond Douglas, MD, PhD, director of the orbital and thyroid eye disease program at Cedars-Sinai Medical Center, told Healio. “This is a major medical breakthrough for a very large percentage of the patient population to receive an alternative medical infusion treatment with great results, quickly.”
As Healio previously reported, the FDA on Tuesday approved teprotumumab (Tepezza, Horizon Therapeutics) for the treatment of adults with thyroid eye disease, marking the first drug approved for the condition. Teprotumumab, an insulin-like growth factor I receptor inhibitor, is a fully human monoclonal antibody developed to address a substantial unmet need for patients with thyroid eye disease. The drug blocks the inflammatory/autoimmune pathophysiology that underlies thyroid eye disease.
In a randomized, double-blind, placebo-controlled trial, Douglas and colleagues analyzed data from 83 adults with active thyroid eye disease assigned in a 1:1 ratio to IV infusions of teprotumumab (n = 41; 10 mg/kg body weight for first infusion; 20 mg/kg body weight for subsequent infusions) or placebo (n = 42) once every 3 weeks for 21 weeks. Last trial visit occurred at week 24. Primary outcome was a reduction in proptosis of at least 2 mm at week 24. Prespecified secondary outcomes included overall response, defined as a reduction of at least 2 points in Clinical Activity Score plus a reduction in proptosis of at least 2 mm, a Clinical Activity Score of 0 or 1 (indicating no or minimal inflation), mean change in proptosis across trial visits, diplopia response and mean change in overall score on the Graves’ ophthalmopathy-specific quality of life questionnaire across trial visits (mean change of 6 points considered clinically meaningful).
At 24 weeks, more people in the teprotumumab group experienced a reduction in proptosis vs. placebo (83% vs. 10%; P < .001), with a number needed to treat of 1.36.
Among adults assigned teprotumumab, researchers observed a greater overall response vs. placebo (78% vs. 7%), as well as more treated adults with a Clinical Activity Score of 0 or 1 (59% vs. 21%), a greater mean change in proptosis (mean, –2.82 mm vs. –0.54 mm), greater diplopia response (68% vs. 29%) and greater mean change in overall quality of life score (mean, 13.79 points vs. 4.43 points; P .001 for all).
Researchers also observed reductions in extraocular muscle, orbital fat volume or both for six adults in the teprotumumab group who underwent orbital imaging.
“For the first time ever, patients and physicians won’t need to watch and wait over many years for this disease to finally become stable,” Douglas said. “It can now be treated in its early stages with great successes comparable in most cases to surgical options. The study demonstrates the remarkable ability of teprotumumab to reverse the underlying disease process, specifically proptosis, diplopia and improve quality of life. This was achieved with a mild side effect profile.”
Douglas said further studies are needed regarding the safety of teprotumumab over time, although the drug appears to be safe.
“We will also need to refine or even individualize how many treatments patients require in their personal plan,” Douglas said. – by Regina Schaffer
For more information:
Raymond Douglas, MD, can be reached at Cedars-Sinai Medical Center, W. Medical Office Towers, 8635 W. Third St., Suite 650W, Los Angeles, CA 90048; email: Raymond.firstname.lastname@example.org.
Disclosures: Horizon Therapeutics sponsored the OPTIC trial and contributed to the writing and review of the final manuscript. Douglas reports he serves as a consultant for Horizon Therapeutics.