Further evidence that the oral drug Orenitram (treprostinil) might be a viable option to Remodulin, the injected version of the drug, for lower risk pulmonary arterial hypertension (PAH) patients was recently published by researchers at Washington University in St. Louis, Missouri.
The study, “Transition from parenteral to oral treprostinil in pulmonary arterial hypertension,” which appeared in the Journal of Heart and Lung Transplantation, is the second one in a short time to support the switch to oral treatment, allowing stable (PAH) patients to trade more burdensome injections for pills.
Intravenous prostacyclins — the drug class with the ability to dilate blood vessels, which Orenitram belongs to – are still the main treatment choice for severe cases of pulmonary hypertension, and are considered the most effective way of treating lung hypertension. But patients need to be connected to a pump constantly injecting drugs into their body, undoubtedly a limiting factor. In addition, IV treatment increases the risk of infections, blood clots, and pain. Injections placed under the skin are also available, but patients may still prefer to take a pill.
Orenitram extended-release tablets were approved in 2013 for PAH patients in WHO Group 1, despite evidence from clinical trials showing it was not overly effective. But later analyses demonstrated that patients in the trials had likely received doses that were too low, and studies proving the feasibility of switching from injection to oral versions continued.
Researchers recruited 33 patients who they believed were stable enough to manage a switch, with patients thoroughly examined beforehand. Patients were also rigorously monitored during the switch, which was done during a five-day hospital stay in which doctors slowly tapered the injection drug while increasing doses of oral Orenitram.
By week four, all patients had started their oral treatment, but two returned to injectables before the final assessment at 24 weeks. At this time point, patients were taking a daily dose ranging between 15 and 75 mg, with 25 out of 31 patients taking the drug three times a day, seven to nine hours apart.
Examinations showed that at the end of the study, patients did not exhibit increased shortness of breath, and they performed equally well on the 6-minute walk distance test. Also, neither symptoms nor WHO functional class worsened, and blood flow and heart function measurements were not affected by the change.
Questionnaires examining quality of life and treatment satisfaction did not show any statistically supported changes, although patients rated the oral treatment as more convenient, and stated that their mood had improved after the shift.
Almost all patients reported they had side effects during the study, most commonly headache, nausea, flushing, diarrhea, fatigue, and vomiting. Also, 27 percent had severe side effects, including diarrhea, nausea, and dizziness. The two patients who returned to injectable drug had both severe side effects and worsening symptoms.