Horizon Therapeutics plc announced the presentation of new data from the randomized, double-masked, placebo-controlled phase 4 clinical trial (NCT04583735) evaluating TEPEZZA in patients with long disease duration and low Clinical Activity Score (CAS), a measure of disease activity.
The oral presentation at the Endocrine Society Annual Meeting (ENDO 2023) supports the efficacy and safety of TEPEZZA in TED patients regardless of disease activity or duration. TEPEZZA is the first and only medicine approved by the U.S. Food and Drug Administration (FDA) for the treatment of TED – a serious, progressive, debilitating and potentially vision-threatening rare autoimmune disease.1
“These data are important because they provide evidence in a controlled, clinical setting that TEPEZZA can significantly improve proptosis and visual functioning as measured by the Graves’ Ophthalmopathy Quality of Life Questionnaire in people who have been living with Thyroid Eye Disease for years and may have thought they were not a candidate for the medicine,” said Raymond Douglas, MD, PhD, the principal investigator of the trial and director of the Orbital and Thyroid Eye Disease Program, Cedars-Sinai Medical Center in Los Angeles. “Thyroid eye disease is a heterogenous disease, and its impact is not always immediately visible, affecting patients both physically in day-to-day activities, and mentally due to the emotional distress that accompanies the disease. It is not too late to help those patients with longer-term symptoms.”
As previously reported, the phase 4 clinical trial met its primary efficacy endpoint (reduction in proptosis) and key secondary efficacy endpoint (proptosis responder rate). At Week 24, per the pre-specified primary analysis method (intent-to-treat), patients treated with TEPEZZA achieved a 2.41 mm reduction in proptosis from baseline compared with 0.92 mm for placebo (p=0.0004) and 62% of patients treated with TEPEZZA had a meaningful improvement in proptosis (≥2 mm) compared with placebo (25%) (p=0.0134).
In the pre-specified per-protocol analysis, patients treated with TEPEZZA achieved a 2.44 mm reduction in proptosis from baseline compared with 0.69 mm for those receiving placebo (p=0.0006) and 63% of patients treated with TEPEZZA had a meaningful improvement in proptosis (≥2 mm) compared with placebo (7%) (p=0.0008) at Week 24.
The results presented at ENDO also showed that TEPEZZA improved visual functioning as measured by Graves’ Ophthalmopathy Quality of Life Questionnaire (GO-QOL), a tool used to measure health-related quality of life in TED patients, scaled from 0 (worst) to 100 (best). At Week 24, in the pre-specified analysis in the intent-to-treat population, patients who received TEPEZZA experienced a significantly greater average improvement from baseline for visual functioning (8.73) compared with placebo (2.41) (p=0.03).
At Week 24, the change from baseline for appearance, also measured by GO-QOL, was 10.03 for TEPEZZA and 7.19 for placebo (p=0.65). The appearance subscale endpoint was not statistically significant: at Week 24, per the pre-specified primary analysis method (intent-to-treat), patients who received TEPEZZA experienced a 10.03 improvement in appearance compared with 7.19 for placebo (p=0.65). No new safety signals were observed.
“Over the past few years, our understanding of Thyroid Eye Disease and the importance of TEPEZZA has continued to expand, fueled by the curiosity and efforts of leaders in the field and our combined commitment to ongoing research,” said Beth Scott, OD, MS, vice president, medical affairs, Horizon. “These trial data support the potential role of TEPEZZA across a broad range of Thyroid Eye Disease patients, no matter how long they have been living with the disease or how much disease activity they have.”
Trial design
This randomized, double-masked, placebo-controlled, parallel-group, multicenter trial evaluated the efficacy, safety, and tolerability of TEPEZZA (n=42) compared to placebo (n=20) in adults who have lived with TED from two to 10 years duration prior to the study and have low CAS.
The primary efficacy objective was to measure the effect of TEPEZZA versus placebo in the change of proptosis measurements in the study eye from baseline at Week 24.
All study participants were required to have an initial diagnosis of TED two to 10 years prior to screening, and a CAS of ≤1 in both eyes for at least one year prior to screening or all of the following one year prior to screening: no progression in proptosis, no progression in diplopia and no new inflammatory TED symptoms. Participants could not have had prior orbital irradiation, orbital decompression surgery or strabismus surgery.
The mean duration of disease for TEPEZZA and placebo patients was 5.1 years (SD 1.88) and 5.4 years (SD 1.61), respectively. The mean CAS for TEPEZZA and placebo patients was 0.3 (SD 0.47) and 0.5 (SD 0.51), respectively.