MT-7117 (dersimelagon) met its primary endpoint in the phase 3 INSPIRE trial for erythropoietic protoporphyria and X-linked protoporphyria, showing favorable efficacy and safety in adult and adolescent patients.
Written By: Pharmacally Medical News Desk
Tanabe Pharma Corporation has reported positive topline results from its global phase 3 INSPIRE study evaluating MT-7117 (dersimelagon) in patients with erythropoietic protoporphyria (EPP) and X-linked protoporphyria (XLP). The trial met its primary endpoint and demonstrated a favorable safety profile, marking a significant step forward for patients with these ultra-rare phototoxic disorders.
MT-7117, also known as dersimelagon, is a novel, orally administered, non-peptide small molecule. It acts as a selective agonist of the melanocortin-1 receptor (MC1R). Activation of MC1R is expected to increase tolerance to light exposure and reduce phototoxic pain in patients with EPP and XLP.
Phase 3 INSPIRE Study Overview
The INSPIRE study (NCT06144840) is a global, randomized, double-blind, placebo-controlled phase 3 clinical trial enrolling adult and adolescent patients diagnosed with EPP or XLP. The study includes a 16-week double-blind treatment period followed by a 36-week open-label extension. During the blinded phase, participants were randomized to receive either placebo or MT-7117 at a dose of 200 mg once daily.
The primary endpoint of the study was the time to first prodromal symptoms associated with sunlight exposure. These early symptoms include burning, tingling, itching, or stinging sensations that typically precede severe phototoxic pain in EPP and XLP patients. According to the topline data, MT-7117 met this primary endpoint, demonstrating favorable efficacy compared with placebo.
Efficacy and Safety Findings
Tanabe Pharma reported that MT-7117 showed a favorable efficacy profile in delaying the onset of prodromal symptoms following light exposure. This outcome is clinically meaningful, as even short periods of sunlight can trigger intense pain in affected patients. The company also confirmed that the therapy demonstrated an acceptable safety profile in the phase 3 study, although detailed numerical data have not yet been disclosed. The open-label extension phase of the INSPIRE study is currently ongoing to further assess long-term safety and efficacy
About EPP and XLP
EPP and XLP are rare inherited disorders of the heme biosynthesis pathway. EPP is primarily caused by mutations in the ferrochelatase (FECH) gene, while XLP results from mutations in the ALAS2 gene. Both conditions lead to the accumulation of protoporphyrin in blood and tissues, causing extreme photosensitivity. Symptoms often begin in early childhood, with painful phototoxic reactions occurring within minutes of sun exposure. Treatment options remain limited, particularly for adolescents, and many patients rely solely on strict sun avoidance measures that significantly impair quality of life.
Development Plans
Tanabe Pharma confirmed its plans to continue advancing MT-7117 as a potential oral treatment for patients with EPP and XLP, with the goal of addressing the significant unmet needs in these ultra-rare disorders. By expanding therapeutic options for both patients and healthcare professionals, the company aims to reduce the burden associated with strict light avoidance and debilitating phototoxic pain. The development program is further supported by the U.S. FDA’s Fast Track designation for dersimelagon, granted in June 2018, underscoring the therapy’s potential clinical value in this underserved patient population.
Reference
MT-7117 Demonstrates Positive Topline Results in Development for the Ultra-Rare Disease, Erythropoietic Protoporphyria (EPP) and X-Linked Protoporphyria (XLP), 15 January 2026, January 15, 2026 MT-7117 Demonstrates Positive Topline Results in Development for the Ultra-Rare Disease, Erythropoietic Protoporphyria (EPP) and X-Linked Protoporphyria (XLP)
INcreased Sun Exposure Without Pain in Research Participants with EPP or XLP (INSPIRE), ClinicalTrials.gov ID NCT06144840, https://www.clinicaltrials.gov/study/NCT06144840
Balwani M. Erythropoietic Protoporphyria and X-Linked Protoporphyria: pathophysiology, genetics, clinical manifestations, and management. Mol Genet Metab. 2019 Nov;128(3):298-303. Epub 2019 Jan 24. PMID: 30704898; PMCID: PMC6656624. https://doi.org/10.1016/j.ymgme.2019.01.020