Rare Diseases
Duchenne Muscular Dystrophy
Duchenne muscular dystrophy (DMD) is an X-linked disorder caused by pathogenic variants in the DMD gene. It primarily affects boys, causing progressive skeletal-muscle weakness and clinically important cardiac and respiratory disease. Atossa is evaluating whether (Z)-endoxifen’s effects on muscle-related signaling pathways could support a mutation-agnostic treatment approach.
Adult Dystrophinopathies
Adults with milder forms of dystrophinopathies such as female carriers of the Duchenne mutation and men with a milder form, Becker’s Dystrophy, may also benefit from the mechanism (Z)-endoxifen. For example, women with a pathogenic DMD variant have a spectrum of manifestations. Many have no skeletal-muscle symptoms, while others experience weakness, fatigue, cramping, elevated muscle enzymes, or clinically important cardiomyopathy. Atossa is evaluating these adult populations as distinct potential clinical-development opportunities.
McCune-Albright Syndrome
McCune-Albright Syndrome (MAS) is a rare mosaic disorder caused by postzygotic activating GNAS variants. Among its manifestations, peripheral precocious puberty in girls can lead to recurrent estrogen exposure, advanced bone age, and compromised adult height. Atossa is investigating whether (Z)-endoxifen could provide a differentiated estrogen-receptor-directed approach in this setting.
Additionally, polyostotic fibrous dysplasia replaces normal bone with weak, fibrous tissue, leading to frequent fractures and deformities. While this mosaic disorder is present at birth and affects boys and girls equally, its broad spectrum of symptoms means symptoms can vary and may not appear until later in childhood.