Privigen is an intravenous immunoglobulin (IVIg) therapy, meaning it delivers concentrated antibodies from donated human plasma directly into your bloodstream through an IV. The FDA has approved it for three conditions: primary immunodeficiency (PI), chronic immune thrombocytopenic purpura (ITP) in patients 15 and older, and chronic inflammatory demyelinating polyneuropathy (CIDP) in adults.
Primary Immunodeficiency
Primary immunodeficiency refers to a group of inherited conditions where the body doesn’t produce enough protective antibodies on its own. People with PI get frequent, severe, or unusual infections because their immune systems can’t fight off bacteria and viruses the way a healthy immune system would. Privigen essentially replaces what’s missing. Each infusion floods the bloodstream with a broad range of antibodies collected from thousands of plasma donors, giving the immune system the tools it lacks to recognize and neutralize common pathogens.
For PI, Privigen is typically given as a recurring infusion every three to four weeks. The goal isn’t to cure the underlying condition but to keep antibody levels high enough to prevent infections over the long term. Most people with PI stay on IVIg therapy indefinitely.
Chronic Immune Thrombocytopenic Purpura (ITP)
ITP is an autoimmune condition in which the body’s immune system mistakenly attacks and destroys its own platelets, the blood cells responsible for clotting. Platelet counts drop dangerously low, leading to easy bruising, bleeding gums, nosebleeds, and in severe cases, internal bleeding.
For ITP, Privigen is given at a higher dose than for PI: one infusion per day on two consecutive days. In a clinical trial of 57 adolescents and adults with chronic ITP whose platelet counts had fallen below 20,000 per microliter (healthy counts range from 150,000 to 400,000), this two-day regimen raised platelet counts above 50,000 in about 81% of patients within seven days. The response also reduced bleeding events. Unlike its role in PI, where it replaces missing antibodies, in ITP the infused antibodies are thought to temporarily distract the immune system from destroying platelets, giving the body time to rebuild its supply.
Chronic Inflammatory Demyelinating Polyneuropathy (CIDP)
CIDP is a rare neurological condition where the immune system damages the protective coating (myelin) around peripheral nerves, the nerves that carry signals between the brain, spinal cord, and the rest of the body. This leads to progressive weakness and impaired sensation in the legs and arms, often developing over weeks to months. Walking, gripping objects, and climbing stairs become increasingly difficult.
Privigen works in CIDP by modulating the overactive immune response that’s stripping myelin from nerves. Treatment typically starts with a larger loading dose, followed by smaller maintenance infusions every three weeks. In the PRIMA study, patients received an initial dose of 2 grams per kilogram of body weight, then maintenance doses of 1 gram per kilogram at three-week intervals for up to seven cycles. The aim is to slow or halt nerve damage and, in many cases, improve strength and sensation over time.
What the Infusion Is Like
Privigen is a 10% liquid solution that comes ready to use, with no mixing or reconstitution required. It’s given through an IV, usually in an infusion center or clinic, though some patients eventually receive infusions at home with training. Each session starts slowly. The initial infusion rate is deliberately low, then gradually increased if you tolerate it well. For PI and CIDP, the rate can be increased up to a maximum of 8 mg/kg/min. For ITP, the maximum is capped lower at 4 mg/kg/min.
If you’ve never had an IVIg infusion before, or if you’re switching from a different IVIg product, or if it’s been more than eight weeks since your last infusion, the rate will be kept particularly slow at first. This is because first-time or returning patients are more likely to experience reactions that mimic flu-like symptoms: headache, chills, nausea, or fever. These reactions are generally tied to how fast the infusion runs, not the medication itself, so slowing the drip usually helps.
Who Should Not Receive Privigen
Privigen is contraindicated in people with a selective IgA deficiency. IgA is one of several types of antibodies the body produces, and people who lack it can develop their own antibodies against IgA. Because Privigen contains trace amounts of IgA (25 micrograms per milliliter or less), these patients can have severe allergic reactions, including anaphylaxis, if it enters their bloodstream.
People who have had a previous severe reaction to any human immunoglobulin product should also avoid Privigen. Additionally, anyone with an allergy to the amino acid L-proline, which Privigen uses as a stabilizer, cannot receive it.
Serious Safety Considerations
Privigen carries a boxed warning for kidney problems. IVIg products have been linked to acute kidney dysfunction and, in rare cases, kidney failure. Patients most at risk include those who already have some degree of kidney impairment, people with diabetes, adults over 65, and anyone who is dehydrated or taking medications that stress the kidneys. Notably, Privigen does not contain sucrose, an ingredient in some other IVIg products that has been specifically associated with kidney damage. Still, for anyone at elevated risk, the infusion is run at the slowest practical rate.
Blood clots are another serious concern. IVIg products, including Privigen, can increase the thickness (viscosity) of blood, raising the risk of stroke, heart attack, deep vein thrombosis, or pulmonary embolism. This risk is higher in people with a history of cardiovascular disease, clotting disorders, prolonged immobility, or advanced age. If you fall into any of these categories, your medical team will typically use a slower infusion rate and monitor you closely.
Storage and Handling
Privigen is stable at room temperature (up to 77°F or 25°C) for up to 36 months, which makes it relatively convenient compared to products that require refrigeration. It should be kept in its original carton to protect it from light and should never be frozen. These storage characteristics are mainly relevant if you receive infusions at home and need to store the product between treatments.