"Published in the March issue of the journal Chest, the research shows that more than half of the patients treated with Viagra, also known medically as Sildenafil, improved their walking distance by at least 20 percent during a standard test to measure lung function..."
This is a nice finding, and plausible in retrospect. By all means add Viagra to the arsenal of palliatives for IPF patients. But it is unlikely to modify the course of the disease substantially (The trial was massively underpowered to determine that). Any survival benefit is likely to be additive with pirfenidone (pirfenidone slows lung scarring; Viagra apparently mitigates the consequences of lung scarring)