Recent findings from a study published in the Journal of Neuro-Ophthalmology assessed the effect of teprotumumab on objective ocular alignment measures in thyroid eye disease (TED) patients.
Give me some background first.
Teprotumumab is a novel human monoclonal insulin-like growth factor 1 receptor (IGF-1R) antibody that is administered intravitreally once every 3 weeks for a total of eight infusions over the course of 6 months.
Though teprotumumab was FDA approved in 2020, its impact on diplopia outcomes in TED patients is still unclear.
And the need for this research?
Studies have largely only reported on the effect of teprotumumab on diplopia subjectively using the Gorman diplopia score.
Thus, a research team from the Wilmer Eye Institute at Johns Hopkins University sought to address this gap in the literature.
Now talk about the study.
In this retrospective study, investigators reviewed the medical records of TED patients 18 years and older who presented with diplopia and underwent a full-course treatment of teprotumumab in a single-center academic ophthalmology practice.
What were the primary and secondary outcomes?
The primary outcome was the change in ocular alignment in primary gaze position at 6 months—marking the completion of teprotumumab treatment.
Similarly, secondary outcomes were measured at 6 months and compared to baseline, including:
- Change in ocular alignment in other gaze positions
- Proptosis
- Eyelid position
- Clinical activity score (CAS)
To note, CAS is a system (similar to the Ocular Surface Disease Index [OSDI]) used to measure TED patients’ symptom severity.
One point is given for the presence of various parameters related to TED and the overall sum of the points defines TED clinical activity.
Anything else?
In order to establish which factors may predict ocular alignment response to teprotumumab, investigators divided the patients into three groups—worsened, stable, or improved ocular alignment at 6 months—and analyzed their baseline characteristics.
Patients categorized as “worse” patients had at least 5D of worsening in the horizontal plane or 3D of worsening in the vertical plane; the inverse was true of improved patients, and measurements in between were labeled “stable.”
Findings?
Of the 17 patients who met the inclusion criteria, their ocular alignment:
- Worsened (18%): 3 patients
- Stabilized (59%): 10 patients
- Improved (24%): 4 patients
What about predictive baseline measurements?
CAS (P=0.02) was significantly different between the three groups: higher in patients who worsened and improved vs those who remained stable.
Similarly, right gaze horizontal prism deviation (P=0.01) and left gaze horizontal prism (P=0.03) were significantly different between groups, with a greater degree of left gaze horizontal prism deviation in the worse group than the stable group (P=0.04).
Expert opinion?
According to the study authors, “These results suggest that those with more active disease at baseline are more likely to change one way or the other instead of remaining stable because the CAS at baseline was higher in those who worsened and improved after teprotumumab treatment.”
They added that those who start out with a greater degree of misalignment at baseline are also more likely to either show improvement or worsening, “as demonstrated by the right and left gaze horizontal prism deviation outcomes,” they stated.
Meaning?
These findings reinforce the notion that more active disease—more specifically, greater degrees of misalignment—at baseline indicates increased odds for some response to teprotumumab, instead of no response or a change in the disease course.
And lastly …
The study authors recommended counseling TED patients with prominent diplopia that further diplopia treatment, such as prisms or strabismus surgery, may still be required following a course of teprotumumab.