Pharmaceutical company Shield Therapeutics plc (LSE: STX) announced on Monday that its partner MEDLEAP Pharma, a subsidiary of Vital KSK Holdings Inc, has enrolled the first patient in a Phase II clinical trial of ACCRUFeR (ferric maltol) for the treatment of pulmonary arterial hypertension (PAH) in Japan.

The study is an exploratory Phase II trial intended to support a future Phase III programme and follows confirmation from Japan's Pharmaceuticals and Medical Devices Agency of the development plan for ACCRUFeR in PAH, based on prior clinical data generated in Europe, the UK and the United States.

Shield Therapeutics said the trial will evaluate the efficacy and safety of ferric maltol in patients with PAH in Japan, where iron supplementation is recommended for patients with iron deficiency in line with European and Japanese clinical guidance. The PAH market in Japan is estimated to exceed USD230m.

ACCRUFeR (ferric maltol) is a non-salt-based oral iron therapy already approved for iron deficiency with or without anaemia and is marketed as a leading branded prescription oral iron in the US. The product is commercialised through multiple licensing agreements across Europe, North America, Asia and Australia, with patent protection extending into the mid-2030s.

The company said the programme represents an expansion of its clinical development strategy for ACCRUFeR into additional therapeutic areas beyond iron deficiency, supported by its partnership with MEDLEAP Pharma in Japan.