Thyroid eye disease (TED), also known as Graves’ ophthalmopathy, is a progressive auto-immune disease that can cause bulging eyes, double vision and, in rare cases, loss of vision. It affects around 50,000 people in the UK (British Thyroid Foundation, 2024 ).

Teprotumumab became the first drug to be approved for TED by the US Food and Drug Ad-ministration in 2020. Amgen, which manufactures it, applied to the UK Medicines and Healthcare products Regulatory Agency for marketing authorisation in March 2024.

Patients with TED who participated in a phase III trial had reduced signs of bulging eye and improvements in other symptoms compared to those given placebo when assessed at the end of a 24-week course of teprotumumab (Douglas et al, 2020 ).

Ophthalmologist Terry J Smith of the University of Michigan and colleagues pooled follow-up data from three trials to investigate whether the improvements were long-lasting in a study published in the journal Thyroid. They checked whether patients had needed additional treatment at various timepoints up to almost two years after their course of teprotumumab.

Nearly two years after the treatment period was complete, 82% of patients did not need further treatment for TED.

However, data was only available on 106 patients at 27 weeks after treatment. Only one of the trials tracked patients for 99 weeks after their last doses, and of the 39 participants in it who completed treatment, only in 19 cases were data available at 99 weeks. Of these, five received additional treatment.

So 14 of 19 patients ( 74%) did not have extra therapy in almost two years following teprotumumab therapy. The finding is encouraging, but would be more so if the study had a larger sample size and a smaller dropout rate.