In 2009, the FDA approved Tyvaso (treprostinil) Inhalation Solution to reduce symptoms associated with Group 1 pulmonary hypertension (PH), also known as pulmonary arterial hypertension (PAH). Beyond symptom reduction, the therapy was also designed to improve exercise ability. Now, in 2021, the Pulmonary Hypertension Association (PHA) shared that Tyvaso has become the first FDA-approved therapy for patients with Group 3 PH, or PH associated with interstitial lung disease. Ultimately, this offers an opportunity to fill a huge unmet need within this patient population.

Tyvaso

Developed and manufactured by United Therapeutics, Tyvaso is a prostacyclin vasodilator approved for use in patients with pulmonary arterial hypertension (PAH; Group 1 PH) and lung disease-associated PH (Group 3 PH). The medication works by relaxing the arteries and allowing for increased blood flow. According to patients who have used Tyvaso in clinical trials, the therapy significantly improves respiration, quality of life (QOL), and ability to exercise.

Considering an estimated 15% of those with early-stage interstitial lung disease and 86% with late-stage lung disease also have PH, this treatment offers the ability to significantly improve QOL for a sizable group.

Although Tyvaso is relatively safe and well-tolerated, some common side effects include:

• Cough
• Headache
• Nausea
• Throat irritation
• Diarrhea

Pulmonary Hypertension (PH)

Pulmonary hypertension (PH) is a form of high blood pressure which affects your heart and arteries. According to the Center for Disease Control and Prevention (CDC):

The heart pumps blood from the right ventricle to the lungs to get oxygen. Because the blood does not have to travel very far, the pressure in this side of the heart and in the artery taking blood from the right ventricle to the lungs is normally low—usually much lower than systolic or diastolic blood pressure [but] when the pressure…gets too high, the arteries in the lungs can narrow and then the blood does not flow as well…resulting in less [blood oxygenation].

PH can occur at all ages. However, the risk increases with age. Additionally, PH is more common in females than males. Altogether, the PHA explains that there are five main groups of PH:

• Group 1: Pulmonary Arterial Hypertension (PAH)
• Group 2: PH due to left heart disease
  • Note: This form of PH is caused by issues with how the heart contracts/relaxes, or with how the valves on the heart’s left side operate. This is considered to be the most common PH diagnosis.
• Group 3: PH due to low oxygen levels or chronic/interstitial lung disease
  • Note: For example, the PHA explains that:

    • These lung diseases include obstructive lung diseases where the lung airways narrow and make it harder to exhale (e.g. COPD or emphysema); restrictive lung disease in which the lungs have a tough time expanding when one inhales (e.g. interstitial lung disease or pulmonary fibrosis); sleep apnea; and living in an area of high altitude for a long period of time.

• Group 4: PH due to chronic blood clots in the lungs (also known as chronic thromboembolic PH)
• Group 5: PH with unknown causes

PH Symptoms

Regardless of the specific group, common PH-related symptoms include:

• Shortness of breath and/or difficulty breathing
• Fatigue
• Dizziness
• Chest pain or pressure
• Swelling in the ankles, legs, and abdomen
• Heart palpitations
• Cyanosis (a blue color to the skin and lips)