Pragmatically, these results raise the possibility that PAH combination therapy trials could be shorter in duration. Some recent event-driven studies have lasted up to 6 years, with patients on treatment for about 2 of those years, investigators noted.
“In the context of an orphan disease with limited and competing recruitment for trials and the rapidly changing treatment paradigm in PAH, the optimal duration of future trials should be revisited,” Dr. Lajoie and her colleagues wrote in a discussion of their findings.
They also cautioned that NNT, a measure of how many patient treatments are needed to prevent one additional adverse event, could be “misleading” despite its value as a simple measure of treatment impact.
Likewise, relative risk can be misleading; for example, a treatment reducing event risk from 30% to 20% represents a relative risk reduction of approximately 35%, but so does a treatment reducing event risk from 3% to 2%, the researchers noted.