Study links stopping Tyvaso to risk of disease worsening
Treatment well tolerated by patients with different types of PH
Tyvaso (inhaled treprostinil) appears to be well tolerated by patients with different types of pulmonary hypertension (PH), and stopping the treatment increases the risk of disease worsening, a study found.
The study, “Evaluation of patients with severe pulmonary hypertension and a range of comorbidities prescribed inhaled treprostinil,” was published in JHLT Open by a team led by researchers from Duke University Medical Center.
PH occurs when the blood pressure in the pulmonary arteries that supply the lungs is higher than normal. In some patients, this occurs secondary to other lung or heart diseases and often worsens a patient’s clinical status.
United Therapeutics‘ Tyvaso contains treprostinil, a compound that mimics prostacyclin, which occurs naturally in the body. Prostacyclin widens and relaxes blood vessels, thereby working as a vasodilator to reduce blood pressure. This is expected to ease symptoms of PH.
It was first approved in the U.S. in 2009 to treat pulmonary arterial hypertension (PAH). Its approval was later extended in 2021 to cover the treatment of PH associated with interstitial lung disease, which is characterized by scarring of the lungs.
Real-world study
The researchers aimed to see how patients with different types of PH respond to Tyvaso in real-world settings. The main goal was to see how long it took for the disease to get worse, which was defined as death, needing a lung transplant, or switching to intravenous (into-the-vein) prostacyclin treatment.
The study involved 270 patients with a median age of 64, who inhaled a median 12 breaths of Tyvaso four times daily. Most patients had severe PH at the time they started treatment with Tyvaso. Response to treatment was checked after three months and again after six months.
Of the 270 patients, 83 (31%) had PAH, 27 (10%) had PH due to left heart disease, 87 (32%) had PH due to lung disease, 30 (11%) had PH due to both heart and lung diseases, and the remaining 43 (16%) had PH due to blood clots or other causes.
After three months, 67 (25%) of patients had stopped treatment with Tyvaso. After six months, this proportion increased to 38.9%. The reasons for stopping included the occurrence of side effects, the treatment not working well, or the disease getting worse.
Those who had not taken Tyvaso for more than seven days had a five times higher risk of disease worsening than those who had continued treatment or had stopped it for less than a week.
Additional sensitivity analysis revealed that the risk of disease worsening was more than nine times higher in patients who had not taken Tyvaso for at least two days when compared with those who either continued treatment or had stopped within two days.
There was no difference in how quickly the disease worsened among the different types of PH. “Our results support the concept that the complexity of PH is not always captured through the current clinical classification system,” the investigators wrote. “Regardless of comorbidities [co-existing disorders], there may be a subset of patients who are responsive to pulmonary vasodilators and benefit from [Tyvaso] treatment.”
Moreover, Tyvaso was “tolerated by the majority of patients,” the team wrote.
Future research, the scientists wrote, should look at the specific characteristics of patients, including whether they have other diseases and how they respond to treatment.
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