Frequently Asked Questions on PAH

In this commentary, James C. Coons, PharmD, FCCP, BCCP; Martha Kingman, DNP, FNP-C; and Vallerie McLaughlin, MD, answer questions from a ProCE webinar on the management of pulmonary arterial hypertension (PAH). Slides from the webinar are also available for self-study or to use in your noncommercial presentations.

What is the average life expectancy for patients with PAH?

Martha Kingman, DNP, FNP-C:
In the 1980s, when there were no FDA-approved therapies, the National Institutes of Health collected survival data: average survival was 2.8 years. Today, we have 14 FDA-approved therapies for PAH and the average survival has improved to 7 years. This is still an unacceptable life expectancy and we hope to continue to see this improve as more therapies come to market.

What is the role of generic medications, in particular parenteral generics, in the treatment of PAH? Why are some PAH centers hesitant to prescribe generics?

Vallerie McLaughlin, MD:
This is a very difficult question. I think provider comfort with equivalency and production are the 2 biggest concerns—warranted or not—that contribute to any hesitancy to use generics in PAH.

PAH medications have a narrow therapeutic range, so we want to know what we’re getting and make sure that any generic is bioequivalent. I think that physicians, providers, and nurse practitioners have a comfort level with what they’re used to using—they want to be sure the patient is on what they’re supposed to be on.

There can also be worries about production. I remember years ago, a generic form of epoprostenol had a production problem forcing the plant to shut down. Everybody who was receiving the generic drug had to be transitioned back to the branded drug, which was very difficult. We were worried about interruptions in therapy.

James C. Coons, PharmD, FCCP, BCCP:
I think that’s a great point. We’ve been faced with the question of whether to use generic PAH drugs at our program, too. In some cases, we have moved to the use of generics, generally with had pretty good success.

The FDA’s approach is to look at bioequivalence, so an agent has to meet a certain range of parameters to be approved as a generic. But for patients with PAH, who can be tenuous, we have to be mindful of potential small differences making a potential big difference.

Martha Kingman, DNP, FNP-C:
We have a handful of patients who are receiving generic IV therapy now. We carefully selected them, including patients who were very stable, not on high doses, and have done well. But we certainly do have a concern. It’s not something that we do lightly, and we also worry about potential supply chain issues in the future.

What about oxygen therapy for patients with PAH?

Martha Kingman, DNP, FNP-C:
Oxygen therapy is very important in patients who are hypoxemic. Generally, patients with idiopathic PAH do not require oxygen unless they are in very advanced stages of disease. We do see hypoxemia in associated conditions, such as congenital heart disease with right to left shunting and in patients with group 3 PH who are hypoxic from their lung disease.

When patients are hypoxic, whatever the reason, we work diligently to correct this with rest, exercise, and sleep. In the office, we assess resting saturation, and from the 6-minute walk test, we determine the need for oxygen with exertion. We perform an overnight oximetry and sometimes a formal sleep study to assess for nocturnal hypoxia. This is critical because hypoxia causes vasoconstriction of the pulmonary arteries, which can increase the pulmonary pressures.

What is the role of inhaled prostacyclins for PAH, particularly for those formulations that may be used acutely in the hospital?

James C. Coons, PharmD, FCCP, BCCP:
There are 2 FDA-approved inhaled prostacyclins for PAH: iloprost and treprostinil. Any other inhaled prostacyclin, including epoprostenol, which is typically compounded in the hospital setting, is off label for PAH.

If inhaled epoprostenol is used, it may be for indications such as prevention or management of right ventricular dysfunction in the perioperative or postoperative cardiothoracic surgical setting. But inhaled epoprostenol has not been adequately studied for PAH and is not formulated in a way that would be conducive to outpatient administration. Therefore, it would not be useful for patients with PAH.

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