Pegloticase (Krystexxa®)
Pegloticase (Krystexxa®) is used to treat the high uric acid levels in gout patients, as well as to improve other manifestations of gout including tophi. It does not treat gout attacks or ease their symptoms.
How does Pegloticase work?
Pegloticase (Krystexxa®) is part of a new class of drugs called PEGylated uric acid-specific enzymes. It treats hyperuricemia that can cause gout by turning uric acid into a substance that your kidneys can more easily eliminate in urine. Pegloticase helps your body dissolve the buildup of uric acid crystals from gout over time. It can work rapidly. In clinical trials, pegloticase lowered uric acid levels to as low as 1 mg/dL (or less) within 24 hours.
Pegloticase is a drug you take to manage your gout and prevent flares, but it will not treat a gout flare or its symptoms.
Pegloticase is given intravenously (IV), administered into a vein after a catheter is inserted by your doctor or nurse. You will get your pegloticase infusion at your doctor’s office or other health care setting. A healthcare professional will watch you while you receive pegloticase. It takes about two hours total to complete the treatment, and while you’re on therapy you’ll need an infusion every two weeks. Because of the fast onset and high effectiveness of pegloticase in lowering uric acid levels and shrinking tophi, it is usually given only for a matter of months in most patients. Your doctor may also want you to come in early to prepare you for the treatment, and watch you for an hour afterward, so plan on spending three to four hours at the doctor’s office.
If you just have hyperuricemia but have not been diagnosed with gout (called asymptomatic hyperuricemia), pegloticase is not recommended. At this time, the FDA has not approved any of the medications that are used to lower urate to be used in patients with high uric acid levels, but without gout.
It may take several months to feel the full effects of pegloticase, and you may still have gout flares early in your treatment. Don’t stop taking pegloticase if you have a gout flare, in fact in some patients gout flares mean pegloticase is working well to remove uric acid from the body. Your doctor can prescribe colchicine, an NSAID or a corticosteroid for you to prevent and treat the gout flares and ease your symptoms.
Your doctor will monitor your urate levels while you take pegloticase to see if the medicine is working. If your uric acid levels increase while you are still receiving infusions, pegloticase may not continue to work for you, or it may work for a while and then stop being effective. If your uric acidrises to above 6.0 mg/dL while on pegloticase, the doctor will discuss the therapy plan with you and may decide to stop your pegloticase infusions. Even patients who stop pegloticase therapy after a few months had important decreases in their uric acid and some resolved tophi as well.
Let your doctor know if you are already taking allopurinol or febuxostat before you start pegloticase, since they should not be taken while on pegloticase. You should also tell your doctor if you have or have ever been diagnosed with heart disease, heart failure or high blood pressure. Females should tell their doctors if they are pregnant, plan to get pregnant or are breastfeeding before starting pegloticase.
Side Effects of Pegloticase
Possible side effects of pegloticase (Krystexxa®) include gout flares and possible allergic reactions. While on pegloticase gout flares can occur in the first few months on therapy, and then tend to become less common after that. The allergic reactions that occur while pegloticase is given tend to occur in patients who have a high uric acid levels (above 6 mg/dL) right before infusions. This is why your doctor will check your uric acid levels before each infusion after the first, and consider stopping therapy if your uric acid levels rise to above 6 mg/dL. Common symptoms of these allergic reactions include hives, chest discomfort or pain, itching, rash, or trouble breathing. Other less common side effects seen with pegloticase include bruising, chest pain, constipation, nausea, sore throat or vomiting.
Let your doctor know right away if you experience any side effects while taking this drug. Your doctor or nurse can monitor you for an allergic reaction when you are getting your treatment, and for an hour or so after to ensure each infusion goes well.
