Calissa: Photodynamic therapy for durable clearance of port-wine stains

Calissa is developing what could become the first FDA-approved drug-device combination for port-wine stains, congenital birthmarks caused by malformed blood vessels in the skin. The company estimates the condition affects about 4 million people across developed markets.

The standard of care, pulsed-dye laser therapy, has remained largely unchanged since 1984. Founder and CEO Jack Hu said the laser targets hemoglobin in vessels 50–150 microns in diameter, but the abnormal vessels responsible for port-wine stains can range from 30–300 microns. As a result, some vessels escape treatment and can reconnect or regrow...