Amgen Reports Positive Phase 3 Tepezza OBI Results

Amgen reports that a phase 3 trial of subcutaneous TEPEZZA delivered by on-body injector met its primary endpoint in adults with moderate-to-severe active thyroid eye disease. During the 24-week placebo-controlled period, proptosis response was 76.7% with treatment and 19.6% with placebo (p<0.0001).

Investigators also reported the key secondary endpoint of mean proptosis reduction at week 24: -3.17 mm for TEPEZZA OBI and -0.80 mm for placebo (p<0.0001). They described statistically significant and clinically meaningful gains in overall responder rate, CAS of 0 or 1, diplopia response measures, complete diplopia responder rate, and GO-QoL appearance, along with a numerical trend favoring treatment on the GO-QoL visual functioning subscale. These outcomes were assessed within the same week 24 evaluation window in the topline readout, outlining a broader pattern of reported improvement across efficacy measures.

The study describes a randomized, double-masked, placebo-controlled, parallel-group, multicenter trial evaluating subcutaneous TEPEZZA against placebo in active TED. Participants received study treatment through an on-body injector every two weeks for a total of 12 injections. Investigators enrolled adults with moderate-to-severe active TED diagnosed within 15 months and proptosis of at least 3 mm from baseline before TED diagnosis. The study also allowed participants with baseline hearing impairment identified by medical history or audiogram, reflecting a fixed subcutaneous regimen delivered on a two-week schedule.

Authors noted that overall safety findings were generally consistent with the known intravenous TEPEZZA profile. They observed mild-to-moderate injection site reactions in some patients, and these events did not lead to treatment interruption or discontinuation. The most common adverse events, each reported in at least 10% of patients, were muscle spasms, tinnitus, weight decrease, ear discomfort, nausea, and diarrhea. This summary reflects the reported tolerability profile for the subcutaneous formulation.

Amgen said the current release provides topline findings from the phase 3 program rather than a full dataset. The company added that full results are planned for presentation at an upcoming medical congress, though the announcement did not name the meeting or provide timing details.

Key Takeaways

• A phase 3 study of TEPEZZA OBI was reported to have met its primary endpoint in adults with active thyroid eye disease.
• Mean proptosis reduction and additional secondary efficacy measures were reported to be improved with TEPEZZA OBI versus placebo.
• Safety was described as generally consistent with intravenous TEPEZZA, injection site reactions did not prompt interruption or discontinuation, and full results are planned for a medical congress.