It’s natural to imagine the worst if you’re diagnosed with a rare disease such as paroxysmal nocturnal hemoglobinuria (PNH). But does PNH really affect your life expectancy? Fortunately, the prognosis (outlook) for PNH has improved with newer treatments, and many people can now live a normal lifespan.

PNH is a blood disorder where the body’s immune system accidentally destroys its own red blood cells (also known as erythrocytes). This process often happens at night, which can cause someone with the condition to wake up with dark-colored urine because of the breakdown of these cells. PNH can cause severe fatigue and shortness of breath, and it increases a person’s chances of developing blood clots and other complications.

What’s the Life Expectancy for People With PNH?

Twenty years ago, a PNH diagnosis meant a high risk of early death. The only treatment options were blood transfusions. People diagnosed with PNH lived an average of 10 to 22 years.

But then, an important discovery changed the prognosis for people with PNH. In the mid-2000s, researchers developed a new type of medication called complement inhibitors. These drugs have dramatically improved life expectancy for people with PNH, and with good management, people with this rare condition can have a normal life expectancy.

The First Complement Inhibitor

The complement system is a group of proteins in your immune system. Think of the complement system as the front-line warriors in your immune system, fighting off invaders such as viruses and bacteria. Sometimes, these warriors are fighting so hard that they start hitting the wrong targets — your red blood cells.

In people with PNH, a mutation (change) in a gene called PIGA damages the protein shield that protects red blood cells. People with PNH can’t defend against the complement system’s attacks. Red blood cells are destroyed in a process called hemolysis. That’s where complement inhibitors come in.

Complement inhibitors are medications that stop the complement system from destroying red blood cells. In 2007, the U.S. Food and Drug Administration (FDA) approved eculizumab (Soliris) as the first complement inhibitor to treat PNH.

Since eculizumab came to market, other complement inhibitors have been approved by the FDA. Thanks to these medications, life expectancy for people with PNH has greatly improved.

What Causes Death in PNH?

The main cause of death in people with PNH is thrombosis (blood clots). Blood clots occur when blood thickens and blocks normal blood flow. Thrombosis (also called thromboembolism or thrombotic events) can happen in the liver, abdomen, or brain in people with PNH. Clots can also travel to the lungs, a condition known as pulmonary embolism. Approximately 40 percent of people with PNH develop thrombosis.

The second most common cause of death is related to bone marrow failure. Bone marrow, the soft spongy tissue inside your bones, makes new blood cells to replace those killed by the complement system. But in people with PNH, the bone marrow can’t always keep up with the demand.

Bone marrow failure has an increased risk of mortality due to potential complications such as:

• Blood cancers
• Infections caused by decreased white blood cells
• Bleeding due to decreased platelets

Bone marrow failure in PNH is often caused by another related bone marrow disorder such as aplastic anemia or myelodysplastic syndrome.

Other serious complications of PNH that might affect your quality of life or survival are:

• Pulmonary hypertension (high blood pressure in the lung arteries)
• Dysphagia (difficulty swallowing)
• Dyspnea (difficulty breathing)
• Abdominal pain
• Kidney disease
• Erectile dysfunction
• Leukemia

What Aspects of PNH Increase Risk of a Shorter Lifespan?

Some factors have been found to raise the risk of shorter life expectancy with PNH, including:

• Comorbidities (coexisting or related health conditions)
• History of solid tumors (cancers) prior to developing PNH
• Infections
• Older age
• Lack of appropriate PNH treatment

New treatment options have reduced the incidence of early death in people with PNH considerably. If you’ve been diagnosed with PNH, it’s important to talk to your doctor about your particular risk factors.

Manage Your Risk With Treatment

A large body of evidence shows that treatment of PNH with complement inhibitors can improve life expectancy. These medications have been found to reduce the destruction of red blood cells, relieve symptoms, and decrease complications that can be life-threatening.

Even people with complex PNH have survival benefits with eculizumab. Eculizumab also significantly reduces the need for blood transfusions.

Eculizumab has been a major step in treating PNH, but it still has its limits. If you take eculizumab, you’ll need infusions every two weeks for the rest of your life. That can be an inconvenience and quite expensive for many people.

There’s also the risk of continued hemolysis — known as breakthrough hemolysis — even if you take this medication regularly. However, more recent complement inhibitors have reduced this risk.

New Complement Inhibitors

In recent years, the FDA has approved new complement inhibitors, including:

• Crovalimab (PiaSky)
• Danicopan (Voydeya)
• Iptacopan (Fabhalta)
• Pegcetacoplan (Empaveli)
• Ravulizumab (Ultomiris)

These newer medications have shown promise for improving life expectancy in people with PNH, but long-term studies will be needed.

These new medications all add up to a longer life expectancy for those who treat their PNH with complement inhibitors. A 2021 study published in the journal Blood looked at thousands of people with PNH. They found that people who took complement inhibitors had an 82 percent chance of surviving for 20 years. In contrast, people who were never treated had a 69 percent chance of surviving for the same period.

Always discuss potential side effects of any new treatment option with your doctor.

Other Treatments

You may also need to treat complications of PNH, like thrombosis. Anticoagulants — also known as blood thinners — aim to prevent blood clots, but they aren’t always successful at treating thrombosis in PNH on their own. Anticoagulants and complement inhibitors are often combined to manage thrombosis in PNH.

However, newer complement inhibitors have been shown to decrease the risk of thrombosis enough that anticoagulants may not be needed. Whether to keep using a blood thinner is decided case by case — people without a past clot usually don’t need one on complement therapy, while those with a prior clot often continue it for longer.

People with severe cases of PNH and bone marrow failure, and who have not responded to medication, may be treated with a bone marrow transplant. Bone marrow transplantation — sometimes referred to as stem cell transplantation — involves replacing damaged bone marrow with healthy stem cells that are provided by a donor.

Although bone marrow transplant is the only treatment that can potentially cure PNH, it has considerable risks and is only recommended for very serious cases.

With the improved outlook of complement inhibitors, most people with PNH can live longer, healthier lives. To improve your life expectancy, be sure to maintain your treatment plan. Keep up with all recommended appointments to help find any PNH complications early. Always talk to your hematology healthcare team if you experience any changes in symptoms.

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On myPNHteam, people share their experiences with paroxysmal nocturnal hemoglobinuria, get advice, and find support from others who understand.

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