Pulmonary arterial hypertension (PAH) is a rare disease that is characterized by abnormally high blood pressure in the blood vessels carrying deoxygenated blood from the right side of the heart to the lungs. PAH is progressive and often fatal. In the United States, there are estimated to be between 30,000 and 50,000 people living with PAH. The five-year survival rate for PAH patients has been reported to be 57%.
Symptoms include shortness of breath at rest or with minimal exertion, fatigue, chest pain, dizzy spells and fainting. The progressive nature of this disease causes the right side of the heart to work much harder and eventually weaken or fail.
PAH is driven by abnormal cellular proliferation within and around the small blood vessels of the lung that carry blood from the right side of the heart to the lungs. Functional and structural changes in the pulmonary vasculature, known as vascular remodeling, can lead to smooth muscle cell proliferation and migration from the middle layer of the blood vessel into the inner layer. This can result in the development of plexiform and neointimal lesions that can obstruct blood flow.
The obstruction of blood flow in the pulmonary vessels can also predispose patients to thrombosis, or blood clots, within these small pulmonary vessels that further blocks blood flow. This progressive obstruction of blood flow from the right side of the heart to the lungs can cause the right ventricle to fail, thus leading to severe breathlessness, reduced exercise tolerance and death.
We believe that seralutinib has the potential to reverse the pathological remodeling by addressing mechanisms that underlie PAH. Seralutinib was designed to inhibit multiple kinases that play a role in the pathology of PAH: PDGFRα/β, CSF1R, and c-KIT. Blocking these proteins reduces inflammation, proliferation, and fibrosis, potentially slowing or reversing the damage caused by vascular remodeling.
Gossamer Bio reported positive topline results from its completed Phase 2 TORREY Study in December 2022. Gossamer Bio is currently enrolling the global registrational Phase 3 study, PROSERA, in adult PAH patients. Topline data from this ongoing clinical trial are expected in the fourth quarter of 2025.
PROSERA Study
Seralutinib in Adult Subjects With Pulmonary Arterial Hypertension (PAH)
CONDITION: Pulmonary arterial hypertension
PHASE: Phase 3 PROSERA study now enrolling worldwide
DESCRIPTION: The primary objective for this trial is to determine the effect of seralutinib on improving exercise capacity in subjects with WHO Group 1 PH who are Functional Class (FC) II or III. The secondary objective for this trial is to evaluate time to clinical worsening.
