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Pharma Friday: Endocrine News Highlights TEPEZZA OBI Phase 3 Results

Endocrine News roundup covering TEPEZZA subcutaneous injector results in thyroid eye disease and Regeneron’s garetosmab FDA priority review for fibrodysplasia ossificans progressiv

GIST

Two notable pharma updates are summarized. Amgen reported positive topline Phase 3 results for TEPEZZA (teprotumumab-trbw) delivered subcutaneously via an on-body injector in moderate-to-severe active thyroid eye disease (TED). The OBI-administered trial met its primary endpoint, showing a 77% proptosis response during the 24-week placebo-controlled period (TEPEZZA OBI 76.7% vs 19.6% placebo; p-value not provided in the extract). Secondary endpoints showed statistically significant improvements in overall responder rate, Clinical Activity Score (0–1), diplopia measures, and GO-QoL appearance subscale; GO-QoL visual functioning subscale showed a non-significant numerical trend favoring TEPEZZA OBI. Safety mirroring the IV profile was noted, with mild-to-moderate injection-site reactions and common adverse events including muscle spasms, tinnitus, weight decrease, ear discomfort, nausea, and diarrhea. No treatment interruptions due to injection-site reactions were reported. Separately, Regeneron announced FDA Priority Review of a Biologics License Application for garetosmab in adults with fibrodysplasia ossificans progressiva (FOP). Garetosmab, a monoclonal antibody targeting Activin A, is supported by the OPTIMA Phase 3 trial, showing large reductions in both new HO lesions and total lesion volume at 56 weeks for two dosing regimens.

Clinical Editorial

Strategic signals from late-stage trials and regulatory activity: - Subcutaneous TEPEZZA expansion with on-body injector: Amgen reported positive topline results from a Phase 3 trial in adults with moderate-to-severe active thyroid eye disease (TED) using TEPEZZA (teprotumumab-trbw) administered via subcutaneous injection with an on-body injector (OBI). The study’s primary endpoint was met, showing a 77% proptosis response rate during the 24-week placebo-controlled period. This compares to a 19.6% response with placebo, with a statistical and clinical meaning assigned to the difference. Additional secondary endpoints demonstrated improvements in overall responder rate,Clinical Activity Score (CAS) 0–1 achievement, diplopia measures (response, complete responder, and ordinal categories), and a favorable change in the Graves’ Ophthalmopathy Quality of Life (GO-QoL) appearance subscale at week 24. A numerical, non-significant trend favored TEPEZZA OBI for GO-QoL visual functioning. Full results will be shared at a forthcoming medical congress. Safety outcomes were broadly consistent with the known IV TEPEZZA profile; injection-site reactions occurred in some patients but did not lead to treatment interruption or discontinuation. The most common adverse events (≥10%) included muscle spasms, tinnitus, weight loss, ear discomfort, nausea, and diarrhea. The sponsor framed the data as extending best-in-class efficacy and delivering IV-level results through a more convenient, subcutaneous route that could broaden patient access. - Regulatory trajectory for garetosmab in fibrodysplasia ossificans progressiva (FOP): Regeneron reported FDA acceptance of their Biologics License Application (BLA) for garetosmab, a monoclonal antibody that inhibits Activin A, for the treatment of adults with FOP, a rare genetic disorder characterized by progressive heterotopic ossification (HO). The FDA issued Priority Review, with an anticipated decision date in August 2026. The BLA is supported by data from the Phase 3 OPTIMA trial, where both 3 mg/kg and 10 mg/kg doses of garetosmab significantly reduced the number and volume of new HO lesions at 56 weeks versus placebo. Specific efficacy signals included a 94% reduction in new HO lesions for the 3 mg/kg cohort and a 90% reduction for the 10 mg/kg cohort in the primary endpoint analysis, with post-hoc analyses showing more than a 99% reduction in mean total lesion volume for both doses. Serious treatment-emergent adverse events were infrequent across groups (1 in 3 mg/kg, 2 in 10 mg/kg, 2 in placebo). The most common adverse reactions (≥30%) included epistaxis, increased hair growth, abscess, and acne. Garetosmab has received Fast Track designation and Orphan Drug designation in the U.S., with Orphan designation in the EU, and additional regulatory submissions planned globally. The safety and efficacy profile remains investigational and not yet approved by any regulatory authority. Executive context and clinical relevance: - TED and subcutaneous administration implications: The reported TEPEZZA OBI results align with prior IV data, positioning subcutaneous delivery as a potential option that preserves efficacy while potentially broadening access through a more convenient administration route. The data reinforce TEPEZZA’s activity across multiple clinical endpoints relevant to TED, including proptosis and functional ocular symptom measures, as well as patient-reported QoL metrics. Interviews with clinical experts emphasize the potential for expanded accessibility and continuity of care given a subcutaneous formulation, while acknowledging the need for full data presentation at scientific meetings. - FOP landscape and regulatory potential: The garetosmab priority review reflects ongoing effort to address HO-driven morbidity in FOP, with the OPTIMA trial suggesting meaningful lesion-level and volumetric reductions. If approved, this agent would add a mechanism-guided approach targeting Activin A to a rare disease with significant functional limitation and high care needs. The regulatory path remains contingent on the FDA’s final assessment of the BLA, with an August 2026 decision window and internationally anticipated submissions. Study design and population snapshots: - TEPEZZA OBI trial context: A Phase 3 randomized framework assessed subcutaneous TEPEZZA delivered via an on-body injector in adults with active TED of moderate-to-severe severity. The primary endpoint focused on proptosis response within a 24-week, placebo-controlled period, accompanied by multiple secondary efficacy measures and a safety profile aligned with IV TEPEZZA experiences. - OPTIMA trial in FOP: A Phase 3 study evaluated garetosmab across two dosing regimens (3 mg/kg and 10 mg/kg) versus placebo, with endpoints centered on the total number and volume of new HO lesions over 56 weeks. The trial also reported safety outcomes including the occurrence of serious adverse events and common adverse reactions. Uncertainties, limitations, and open questions: - Depth of data access: While topline results for TEPEZZA OBI show significant signal across primary and several secondary endpoints, full results will be presented later, leaving some details (such as long-term durability beyond the 24-week window and broader safety signals) to be confirmed at the congress. The available safety profile mirrors known TEPEZZA IV data, but comprehensive comparative safety in a subcutaneous context awaits fuller data disclosure. - Regulatory status for garetosmab: The FDA has granted Priority Review and Fast Track designation, yet formal approval is not established until the August 2026 decision date. Although OPTIMA provides robust efficacy signals, post-approval safety monitoring and real-world performance remain to be determined. Operational implications for practice and access: - If approved or advanced, TEPEZZA OBI could diversify administration pathways for TED, potentially reducing treatment complexity and expanding patient reach in settings where IV infusions pose logistical challenges. Clinicians may anticipate a shift in workflow associated with subcutaneous self-administration or assisted administration via an on-body device, subject to safety and labeling considerations. - For FOP, a regulatory milestone with garetosmab could introduce a disease-modifying option that directly targets a pathogenic driver of HO formation. Given the rarity and progressive nature of FOP, the regulatory decision will likely influence future development strategies for Activin A–modulating therapies and the broader field of rare skeletal disorders. Contextual reflections and editorial notes: - Broad takeaway: Both topical and systemic approaches in these updates illustrate ongoing momentum in niche endocrine- and connective-tissue–related conditions, emphasizing advancements that aim to improve patient experience without compromising efficacy. The emphasis on delivery modality and targeted mechanisms underscores a trend toward patient-centered design in rare disease therapeutics. - Notable limitations in the presented material: The summaries rely on topline results without full trial datasets, and several secondary outcomes are reported without complete numerical detail in this source. Readers should await the forthcoming congress presentations and published full-text reports for comprehensive interpretation, including the magnitude of effect across all endpoints and a fuller safety taxonomy. Bottom-line statement: - The current brief highlights a potentially practice-changing subcutaneous formulation of TEPEZZA for TED, along with a regulatory pathway consideration for garetosmab in FOP based on compelling Phase 3 data. While these developments suggest meaningful advances, definitive conclusions await complete data disclosure and regulatory determinations. The source notes explicitly that “inclusion in Pharma Fridays does not suggest endorsement,” and emphasizes that safety and efficacy remain investigational until authorities authorize final use.

Original source: https://endocrinenews.endocrine.org/pharma-friday-april-10-2026/