Chronic kidney diseases represent a growing worldwide problem with a lack of effective treatments. An improved understanding of the biology of kidney disease is fueling growing drug development activity. Chinook Therapeutics is focused on rare, severe chronic kidney diseases with well-defined clinical pathways. Its lead clinical program, atrasentan, is in a late-stage study in IgA nephropathy, a leading cause of chronic kidney disease. We spoke to Tom Frohlich, chief operating officer of Chinook, about rare kidney diseases, the company’s lead therapeutic candidate, and its plans for commercialization.