Shield Therapeutics plc announced that its Japanese partner MEDLEAP Pharma has initiated a Phase II clinical trial for ACCRUFER (ferric maltol) as a treatment for pulmonary arterial hypertension (PAH) in Japan. The exploratory study follows confirmation by the Pharmaceuticals and Medical Devices Agency (PMDA) of the development plan based on previous clinical results in Europe, the UK, and the USA.
Trial Design and Objectives
The multi-center, randomized, placebo-controlled, double-blind study will enroll approximately 26 patients across Japan. The primary endpoint is the 12-week 6-minute walk distance change from baseline, a standard measure of functional capacity in PAH patients. Secondary endpoints include cardiac function-related efficacy parameters, safety, and tolerability assessments.
Subject to positive results from this Phase II trial, MEDLEAP plans to conduct a Phase III pivotal study and proceed with regulatory submission and launch preparations from 2028 onwards. The company positions ACCRUFER as a core pipeline asset in the PAH field.
Addressing an Unmet Medical Need
Professor Masaharu Kataoka from the University of Occupational and Environmental Health, Japan School of Medicine, highlighted the clinical rationale for the study: "Iron deficiency anemia is highly prevalent in PAH patients and is associated with various clinical manifestations of PAH, including symptoms, exercise tolerance, right heart function, and hemodynamic parameters."
Current iron supplementation treatments face significant challenges in long-term management due to gastrointestinal side effects and low absorption efficiency. Professor Kataoka noted that ferric maltol represents "a completely new compound that overcomes these challenges and enables long-term administration" in PAH patients.
Market Opportunity and Clinical Guidelines
The PAH market in Japan is estimated to be worth over $230 million in 2024. Iron supplementation is strongly recommended for PAH patients with iron deficiency anemia according to both European and Japanese treatment guidelines, including the ESC/ERS Guidelines for the diagnosis and treatment of pulmonary hypertension 2022 and Japan Pulmonary Hypertension and Pulmonary Circulation Society Guidance 2024, both carrying a Class I recommendation.
About ACCRUFER
ACCRUFER (ferric maltol) is a novel, stable, non-salt-based oral therapy that has demonstrated efficacy and tolerability in clinical trials for iron deficiency. The drug features a novel mechanism of absorption compared to other oral iron therapies and is the first and only FDA-approved oral iron treatment for iron deficiency with or without anemia.
Dr. Jackie Mitchell, VP of Quality, RA and Clinical Development at Shield, commented: "Shield is delighted with the rapid progress our partner MEDLEAP Pharma has made in agreeing a PAH development plan with PMDA and initiating the Japanese clinical program to develop ACCRUFER for this exciting new indication."
Partnership Structure
MEDLEAP Pharma, a subsidiary of Vital KSK Holdings Inc., was established in September 2025 with the philosophy of "Bringing innovation to Japan's medical future through the creation of original pharmaceuticals." The company focuses on reducing drug lag in Japan through new drug introduction support and collaboration with domestic and international research institutions.
