New findings from a study published in Ophthalmic Plastic and Reconstructive Surgery compared the clinical outcomes of patients with thyroid eye disease (TED) treated with intravenous teprotumumab, orbital decompression, or both interventions in sequence.
Give me some background first.
In TED, the orbital fibroblasts are activated by autoantibodies, resulting in orbital inflation early on in the disease course and subsequent fibrosis.
This can lead to inflammation behind the eyes and physical and emotional distress for patients due to proptosis (bulging) and diplopia, among other symptoms.
How is TED treated?
Teprotumumab is designed to block insulin-like factor growth factor 1 receptors (IGF-1Rs) to halt the signaling pathway that results in inflammation behind the eyes.
Which leads us to …
A University of California, Los Angeles (UCLA) research team sought to compare the efficacy of teprotumumab with surgical orbital decompression.
The goal: assess if they demonstrated additive results when treated sequentially.
Now, talk about the study.
This non-randomized study included 139 total patients organized into four cohorts:
- Decompression only
- Teprotumumab only
- Teprotumumab first with decompression later
- Decompression first with teprotumumab later
What were the main study outcomes?
The primary outcome measured the change in exophthalmometry (anterior positioning of the globe in relation to the orbital rim).
Secondary outcomes included:
- Change in extraocular muscle motility
- Strabismus
- Diplopia
- Side effects
What was the mean follow-up period?
The mean duration for early follow-up was 1.2 months for both decompression and teprotumumab groups.
Meanwhile, the mean late follow-up was 14.4 and 8.2 months for the decompression and teprotumumab cohorts, respectively.
Findings?
The mean change in exophthalmometry was significantly greater for the decompression group (3.5 mm) compared to teprotumumab (2.0 mm) at late follow-up.
Conversely, the improvement in total extraocular muscle restriction was significantly higher in the teprotumumab group (14.7°) than in the decompression group (2.6°).
What about treatment outcomes with diplopia and proptosis?
The teprotumumab cohort had a notably higher percentage of patients with a diplopia score >1 at baseline and late follow-up (p<0.01) in comparison to the decompression group.
Additional treatment with teprotumumab or decompression—when previously treated with the opposite—resulted in a similar proptosis reduction effect as that therapy alone.
Of note, there were only 11 patients in the study who received both treatments.
Expert opinion?
According to the study authors, “The sample size limits the capacity to comment on the relative efficacy of a particular sequence of decompression and teprotumumab.”
“The reported differences at baseline may be related to a preferential selection of patients presenting with diplopia and restriction towards therapy with teprotumumab,” they added.
Take home.
The findings of this study suggest that surgical decompression has a greater effect on proptosis reduction than teprotumumab, while teprotumumab better improves extraocular muscle motility.
Adding teprotumumab or decompression to a previous course of the opposite adds a similar effect to the supplemental treatment alone.
The study authors recommended that further studies include randomly assigned group status to mitigate bias.