Horizon Pharma announced that more detailed results from the 48 week off-therapy follow-up to the phase 2 clinical trial of teprotumumab for people living with moderate-to-severe active thyroid eye disease (TED) were presented at the AAO annual meeting, Oct. 27–30, 2018, in Chicago. The data was presented in an oral session, “Diplopia Response in a Controlled Trial with Teprotumumab, an IGF-1 Receptor Antagonist Antibody for Thyroid Eye Disease.”
During active TED, which can last up to 3 years, the insulin-like growth factor 1 receptor (IGF-1R) is overexpressed on orbital fibroblasts, resulting in local inflammation and tissue expansion. This can lead to proptosis, or bulging of the eye, and depending on the degree of proptosis, pressure is created on the eyeball within a tight orbital space that can cause multiple eye symptoms. Displacement of the eye muscles subsequently cause ocular misalignment, or strabismus; as a result of which, many people living with TED also endure challenges with double vision, known as diplopia.
“Diplopia is viewed as a hallmark for more serious TED, resulting from swelling and thickening of the extraocular muscles, causing the eyes to move out of alignment,” Raymond Douglas, MD, PhD, one of the study’s principal investigators and director of the orbital and thyroid eye disease program, Cedars-Sinai Medical Center, said in a company news release. “The objectives of this analysis were to examine the diplopia findings in this 24-week controlled trial as well as the additional 48-week long-term follow-up after medicine discontinuation.”
The analysis of this phase 2 exploratory endpoint shows that 69.2 percent (18/26 patients) of those with diplopia improvements of at least one grade at week 24 maintained these improvements at week 72 (48 weeks following treatment period). The phase 3 confirmatory trial and extension studies will evaluate diplopia in people with moderate-to-severe active TED. Teprotumumab is an investigational medicine and its safety and efficacy have not been established.
“These data are one of the few presentations selected for the oral sessions at this year’s AAO meeting, which speaks to the growing interest we see in the potential role that teprotumumab may have in the treatment of active TED,” said Elizabeth Thompson, PhD, vice president, clinical development, rare diseases, Horizon Pharma plc. “We understand there are many challenges for those living with active TED and our ongoing clinical trial and extension study are exploring the potential of teprotumumab to have a significant impact on the treatment approach for these patients.”