Opsumit for Pulmonary Arterial Hypertension: What You Need to Know
Pulmonary arterial hypertension (PAH) is a type of high blood pressure in the arteries that go from your heart to your lungs. It happens when these arteries become narrow or blocked, making it harder for blood to flow through them. This forces your heart to work harder to pump blood.
PAH is a long-term condition that can get worse over time. As the heart works harder, it may become weaker and less able to pump blood well. Many people notice symptoms such as shortness of breath, tiredness, chest pain, or swelling in the legs and ankles.
While there is no cure for PAH, your health care provider will work with you to create a treatment plan that fits your needs. Your plan may include medicines that relax or widen the blood vessels in your lungs to improve blood flow.
One option is Opsumit (macitentan). Opsumit is FDA-approved to treat adults who have PAH. It helps delay the worsening (progression) of the condition and lower the risk of hospital stays related to PAH. It comes as an oral tablet — it's taken by mouth.
If you have PAH, you may be wondering how Opsumit works and what to expect during treatment. This article answers common questions about Opsumit for PAH.
Is Opsumit Right for Me?
To find out if Opsumit is right for you, your health care provider will look at your medical history, including the type of pulmonary hypertension (PH) you have, your symptoms, and your overall health.
Pulmonary hypertension is a general term for high blood pressure in the lungs. The World Health Organization (WHO) classifies PH into five groups. Opsumit is FDA-approved to treat adults with PAH, which is WHO group 1.
Your health care provider will also consider your symptoms and how much they affect your ability to be active. PAH symptoms are rated according to the following WHO functional classes.
- Class I: You have no symptoms with ordinary activity.
- Class II: You feel short of breath or tired during normal activity, but you feel comfortable at rest.
- Class III: Even lighter activity causes shortness of breath or tiredness, but you feel comfortable at rest.
- Class IV: You have symptoms even while resting.
Opsumit tablets were shown to be an effective treatment for PAH in people who had WHO functional class II or III symptoms.
Opsumit may also be used for other conditions as determined by your health care provider. Opsumit is only approved for use in adults. It is not known if this medicine is safe or effective for children.
How Does Opsumit Work for PAH?
PAH is a type of high blood pressure in the lungs. It happens when the pulmonary arteries (the blood vessels that go from your heart to your lungs) become narrow or blocked. This increases the pressure inside the pulmonary arteries and forces your heart to work harder to pump blood to your lungs. Over time, the artery walls become thicker, making the space where blood can flow even more narrow.
People with PAH may have too much or too little of certain natural substances in your body called endothelin, nitric oxide, and/or prostacyclin. These substances normally help keep blood vessels relaxed and open. The goal of medicines for PAH are to balance these substances, which can help your lungs work better and make sure blood can move easier through your veins to your lungs.
Opsumit works by blocking endothelin-1, a substance that tightens blood vessels and worsens lung damage in people with PAH. By blocking endothelin-1, Opsumit helps relax the blood vessels and lower the blood pressure in the lungs. This can help your heart pump blood better and prevent the damage from getting worse.
How Do I Take Opsumit?
Opsumit is a tablet taken by mouth once a day with or without food. Follow your health care provider’s instructions carefully. Do not stop taking Opsumit unless your health care provider tells you to.
How Was Opsumit Studied for PAH?
The effect of Opsumit on PAH was studied in a large clinical trial called SERAPHIN. To join the study, adults had to have a confirmed diagnosis of PAH. They could not join if they were already taking a medicine for PAH that works the same way as Opsumit (an endothelin receptor blocker). The people in the study were randomly assigned to take either Opsumit or a placebo (a pill with no active medicine). Neither the people being studied nor their health care providers knew which one they were taking.
During the study, people took Opsumit tablets or a placebo once a day. The main goal of the study was to find out if long-term use of Opsumit reduces death or PAH-related problems.
The study included 742 people with PAH. They were grouped by how much their symptoms affected daily activity (WHO functional class). Most people were in class II (52%) or class III (46%), meaning they had mild to moderate symptoms with activity. Two percent of people were in class IV (symptoms while resting).
The following information describes the people who took part in the study.
- The average age was 46 years.
- About 77% were female and the rest were male.
- Most were White (55%), about 29% were Asian, about 3% were Black, and the rest were of other races or not reported.
- On average, people had been diagnosed with PAH around 2.7 years before joining the study.
- More than half (57%) of them had PAH that was idiopathic (no known cause) or heritable (runs in families). The rest had PAH that was related to connective tissue disease (31%), congenital heart disease that had been surgically repaired (8%), or other causes (4%).
At the start of the study, most people (64%) were already taking other standard PAH medicines. Of those that were taking other PAH medicines, 61% were taking a stable dose of oral phosphodiesterase-5 (PDE5) inhibitors (such as sildenafil or tadalafil), and about 6% were using inhaled or oral prostanoids (such as epoprostenol or treprostinil). About 36% were not taking any medicine for PAH.
What Benefits of Opsumit Were Seen?
The main goal (primary endpoint) of the SERAPHIN study was to find out how many people died, had a major PAH-related problem during treatment, or experienced worsening of PAH during treatment or within a week after their last dose. To count as a major PAH-related problem, a person had to have one of the following events.
- Worsening PAH that required a lung transplant or a balloon atrial septostomy (a procedure to improve blood flow to the lungs)
- Started a new advanced treatment, such as injected prostanoids
- At least a 15% drop in walking distance on a six-minute walk test plus worsening PAH symptoms and the need for another PAH-specific medicine
People in the placebo group took it for about 25 months (median of 101 weeks), while those in the Opsumit group took it for about 29 months (median of 118 weeks). (Median is the midpoint in a set of results.)
The study found that 31% of people on Opsumit had a major PAH-related problem, compared to 46% of those taking placebo. Opsumit reduced the chance of these events by 45%, showing that people taking Opsumit were less likely to have worsening PAH during the study and more time without a serious PAH-related problem compared to placebo.
Of the people who had a major PAH-related problem, the following outcomes were seen.
Outcome | Opsumit Group | Placebo Group |
|---|---|---|
Worsening PAH | 24% | 37% |
Needed to start an advanced treatment with injectable prostanoids | 0.4% | 2.4% |
Death | 6.6% | 6.8% |
No people in the study needed a lung transplant or balloon atrial septostomy.
Overall, the SERAPHIN study showed that fewer people taking Opsumit died or had a major PAH-related problem compared with people taking a placebo.
Your results may differ from what was seen in clinical studies.
Are There Other Potential Benefits of Opsumit Based on Studies?
Along with the main study goal, the SERAPHIN study also looked at a secondary endpoint of PAH-related death or hospitalization. Secondary endpoints can help provide more information about a medicine’s possible benefits, but they are not the main goal used to prove how well a treatment works.
In the study, the chance of PAH-related death or hospitalization for PAH was lowered by 50% in people taking Opsumit compared to placebo.
- About 19% of people taking Opsumit were hospitalized for PAH, compared to about 32% of those taking placebo.
- About 2% of people taking Opsumit or placebo died due to PAH.
Exercise ability was measured by the six-minute walk test, which measures how far a person can walk in six minutes. After six months, people taking Opsumit walked about 22 meters farther than those taking a placebo. Improvement in the walk test was greatest in those with a worse WHO functional class (class III or IV) at the beginning of the study.
Individual results can vary. Talk with your health care team about the plan to monitor how well your PAH treatment plan is working.
How Long Was Opsumit Studied, and What Do We Know About Its Long-Term Effects?
Some people continued taking Opsumit after the main study ended, and the researchers followed them for many more years in what’s called an open-label extension. This means everyone knew they were taking Opsumit. The median treatment time was 4.6 years. Among the 242 people who continued taking it:
- 95% were still alive after a year.
- 89% were still alive after two years.
- 73% were still alive after five years.
- 63% were still alive after seven years.
But this extended part of the study did not include a placebo group for comparison. So the findings cannot tell us whether Opsumit itself affected survival over the long term.
If you have questions about the long-term effects of Opsumit, talk with your health care provider.
What Are the Side Effects of Opsumit, and How Can I Manage Them?
The most common side effects seen with Opsumit were stuffy nose, sore throat, or common cold symptoms, headache, flu, low levels of red blood cells, and kidney or bladder infection.
To help prevent headaches, be sure to get enough sleep at night, exercise regularly, eat regular meals, drink plenty of water, and limit stress.
To reduce the risk of infections when taking Opsumit, it is important to follow good hygiene practices such as washing your hands, disinfecting surfaces, and avoiding contact with people who are sick. Call your health care provider if you have any signs of infection, such as a fever, chills, or a cough that does not go away. Drink plenty of water to help keep bladder infections away. Tell your health care provider if you have bladder pain, blood in your pee, or the need to pee frequently or if you feel burning or pain when you pee.
Fluid retention (edema) can happen with Opsumit and may be serious. It can happen within weeks of starting Opsumit. Weigh yourself every day, and tell your health care provider if you have unusual weight gain or swelling in your ankles, legs, belly, or other areas.
Opsumit can cause low red blood cell counts (anemia). This is more common during the first weeks after starting Opsumit. Anemia can make you feel more tired than usual or have shortness of breath. If your red blood cells are very low, you may need a blood transfusion. Your health care provider will have you do blood tests before you start and while you are taking Opsumit. Keep all appointments for blood tests, and tell your health care provider if you have any new or bothersome symptoms.
Opsumit may cause liver problems. You will need a blood test to check for liver problems before you start treatment. If you get liver problems during treatment, you may need to have blood tests more often. If you notice symptoms of liver problems, such as nausea or vomiting, loss of appetite, pain or tenderness in your right upper stomach area (abdomen), feeling very tired, yellowing of your skin or whites of your eyes, dark pee, fever, or itching, tell your health care provider right away.
Do not take Opsumit if you are pregnant, as it can cause harm to a fetus. Talk to your health care provider if you are pregnant, are planning to get pregnant, or become pregnant while using Opsumit. If you can get pregnant, you should use effective birth control while taking Opsumit and for at least one month after your last dose. Talk with your health care provider about what birth control is a good choice for you. You should also have a negative pregnancy test before starting Opsumit. Tell your health care provider right away if you have unprotected sex or you think your birth control has not worked. If this happens, you may need to use emergency contraception.
Opsumit may lower sperm count. Talk to your health care provider if this is an important concern for you.
These are not all of the possible side effects of Opsumit. Talk with your health care provider if you are having symptoms that bother you. If you experience anything that you think may be caused by Opsumit, you can also report side effects to the FDA at 800-FDA-1088 (800-332-1088).
What Type of Drug Interactions Can Happen?
There are many other medicines that can increase or decrease the blood levels of Opsumit, which could increase your risk for side effects or make Opsumit not work as well. These medicines are called cytochrome CYP3A and CYP2C9 inducers and inhibitors. Some examples include rifampin, which is a medicine used to treat certain bacterial infections, and fluconazole, which is a medicine used to treat fungal infections. Tell your health care provider about all the prescription and over-the-counter medicines and supplements you are taking. Your health care provider can tell you if you are taking a medicine or supplement that affects CYP3A or CYP2C9.
How Can I Get Opsumit? Can I Get It at Any Pharmacy?
Opsumit requires a prescription from a health care provider. It is a specialty medicine. Your local pharmacy may not carry it. Instead, your health care provider will likely send your prescription to be filled by a specialty pharmacy. The specialty pharmacy will make arrangements with you to ship the medicine to your home.
Is There Any Cost Assistance Available?
There is a patient support program offered by the drugmaker that may help you afford Opsumit. Your health care provider can help you get started. You can find out more at www.opsumit.com/patient-support/pah-companion or by calling 866-228-3546.
