What indicators do you use to determine whether a patient is having a favorable or unfavorable response to nintedanib?

Unfortunately, there probably isn't a way to do this. It might be helpful to step back and see what nintedanib buys you: as compared to placebo, the nintedanib group suffered less FVC decline by ~110mL/year. Real-world data suggest there's probably a mortality benefit if you have your patients on it for a while (probably for years). So, the average patient sitting in front of you in the office is still going to experience PFT decline, but now they're also likely going to have GI side effects. They feel worse! It's a good medicine and has a role in the treatment of these patients, but treating and requesting patient buy-in really takes a leap of faith.

At the present time, the best we can achieve is slowing and stabilization of fibrosis. This is important because there is a direct correlation with decrement in lung function and the extent of disease as seen on HRCT with patient morbidity and mortality. Patient symptoms, FVC, DlCo, and HRCT are all essential in evaluating the efficacy of the therapy. Monitoring of these parameters should be considered about 3-4 months into therapy, and then every 6 to 12 months, depending on the trajectory of the disease course.

I look for evidence of stabilization of decline in pulmonary function testing coupled with tolerability from a side effect standpoint. I always have a shared medical decision discussion with my patients. My goal is to stabilize their lung function (which hopefully translates into longer life lived, preserved exercise tolerance and independence) without decreasing my patient's quality of life. Most of the time, adverse events can be managed, but if not, we discuss a trial of pirfenidone (also associated with GI and has phototoxicity) versus abandoning antifibrotics and consideration of a clinical trial. The decision to stop nintedanib in the setting of the ongoing significant decline in pulmonary function testing (as opposed to troublesome s...