According to a story from Pharmaceutical Business Review, the pharmaceutical company Bayer has recently announced encouraging findings from its phase 4 clinical study. This trial was testing the drug riociguat (marketed in the US as Adempas) as a treatment for pulmonary arterial hypertension, a rare disease affecting the lungs. The drug was being evaluated side by side against another class of treatments used for the disease called phosphodiesterase-5 (PDE5) inhibitors.
About Pulmonary Arterial Hypertension (PAH)
Pulmonary arterial hypertension is a condition in which the blood pressure in the arteries of the lungs is abnormally high. The cause of pulmonary arterial hypertension is often unknown in many cases. However, there are a variety of potential causes, such as certain heritable genetic mutations, exposure to certain toxins, and drug use (ex. methamphetamine). It can also appear as a symptom or complication in a number of other diseases, such as heart disease, connective tissue disease, and infection with HIV. The arteries in the lungs are often inflamed. Symptoms of this condition include rapid heartbeat, poor exercise tolerance, shortness of breath, fainting, leg swelling, fatigue, and chest pain. Treatment may include a number of medications and surgical operations, including lung transplant. A transplant can cure the condition, but it can cause many complications. Survival rate is often only about two or three years without treatment, but the latest drugs can prolong life by several years or more. Click here to learn more about pulmonary arterial hypertension.
Trial Findings
The phase 4 trial was international in scale, with trial sites in 22 countries. It lasted for 24 weeks and included a total of 226 patients. These patients were considered intermediate risk and were no longer responding adequately to either PDE5 inhibitor monotherapy or PDE5 plus endothelin receptor antagonist (ERA) therapy.
The endpoint of clinical improvement in absence of clinical worsening was achieved in 41 percent of patients who switched to riociguat and only in 20 percent of patients who continued their PDE5-based regimen.
These results suggest that intermediate risk patients who are no longer response to PDE5 inhibitors should consider making the switch to riociguat in order to improve their pulmonary arterial hypertension.
