Xtrenbo (Denosumab-Qbde) for Multiple Myeloma

Xtrenbo (denosumab-qbde) is a prescription medication approved by the U.S. Food and Drug Administration (FDA) to prevent bone problems, also called skeletal-related events, in people with multiple myeloma.

How Xtrenbo Works and How It’s Taken

Xtrenbo is a type of medicine called a RANK ligand (RANKL) inhibitor. It works by blocking RANKL, a protein that helps activate cells that break down bone. In multiple myeloma, this may help lower bone damage and other bone problems.

Doctors prescribe Xtrenbo to help prevent skeletal-related events, which are serious bone problems linked to multiple myeloma. These serious bone problems can include broken bones, radiation treatment to bone, surgery to bone, and spinal cord compression.

Xtrenbo is given as an injection under the skin by a healthcare provider. It is given every four weeks. It may be given in the upper arm, upper thigh, or abdomen.

Typical Dosing for Multiple Myeloma

The recommended dose of Xtrenbo for multiple myeloma is 120 milligrams given as an injection under the skin every four weeks.

This information is based on the prescribing information, but your healthcare provider may tailor your treatment plan. Always follow their guidance.

Xtrenbo Side Effects

In clinical studies of Xtrenbo for preventing skeletal-related events in people with multiple myeloma, the most common side effects occurred in about 11 percent to 34 percent of people. These include:

Diarrhea
Nausea
Anemia (low red blood cell count)
Back pain
Thrombocytopenia (low platelet count)
Peripheral edema (swelling, usually in the legs, ankles, or feet)
Low calcium levels
Upper respiratory tract infection
Rash
Headache

Serious Side Effects and Warnings

Xtrenbo can cause serious side effects that may require immediate medical attention. These include:

Hypersensitivity — Severe allergic reactions, including anaphylaxis, can cause trouble breathing, swelling of the face or throat, hives, or a sudden drop in blood pressure.
Hypocalcemia — Low calcium levels in the blood can be severe and cause symptoms.
Osteonecrosis of the jaw — Jawbone damage can cause jaw pain, tooth or gum infections, or sores in the mouth that do not heal.
Atypical femur fracture — A rare thigh bone fracture may cause new or unusual thigh, hip, or groin pain.
Multiple vertebral fractures after stopping treatment — More than one broken bone in the spine after Xtrenbo is discontinued.
Embryo-fetal toxicity — This medication can harm a fetus if used during pregnancy.

Get medical help right away if you think you are having a serious reaction.

What To Know Before Taking Xtrenbo

Before you start Xtrenbo, your doctor will check your calcium level. Low calcium must be corrected before treatment starts. Your doctor may also recommend calcium and vitamin D to help treat or prevent low calcium levels.

Tell your doctor if you have any allergies to denosumab-qbde or any ingredients in Xtrenbo. Do not take Xtrenbo if you have had a serious allergic reaction to Xtrenbo or any of its ingredients.

Tell your doctor if you have kidney problems or are on dialysis. You may have a higher risk of low calcium.

Tell your doctor about all medicines you take, including prescription drugs, over-the-counter medicines, vitamins, and herbal supplements.

Your doctor should check your mouth and teeth before you start Xtrenbo. Keep your mouth clean, and tell your dentist you are taking Xtrenbo. Avoid invasive dental procedures during treatment when possible.

Xtrenbo is also FDA approved to treat adults and skeletally mature adolescents with giant cell tumor of bone that cannot be removed by surgery or where surgery may cause serious problems. It is also approved to treat hypercalcemia of malignancy that did not respond to bisphosphonate therapy.

If you are pregnant, planning to become pregnant, or breastfeeding while taking Xtrenbo, talk with your doctor about the risks and benefits.

Xtrenbo can harm a fetus. If you can become pregnant, your doctor will check that you are not pregnant before treatment. Use effective birth control during treatment and for at least five months after your last dose.

Community FAQs

These answers are fact-checked by our editorial staff.

How effective is Xtrenbo?

In a clinical study of 1,718 people with newly diagnosed multiple myeloma and bone lesions, Xtrenbo was shown to be similar to zoledronic acid in delaying the first skeletal-related event. A skeletal-related event is a serious bone problem, such as a broken bone, radiation therapy to bone, surgery to bone, or spinal cord compression.

Overall survival was similar between the two treatment groups.

Xtrenbo also reduced levels of a marker of bone breakdown called uNTx/Cr by about 75 percent by week 5. These reductions were maintained throughout the study, with levels remaining about 74 percent to 79 percent below baseline from weeks 9 through 49 when Xtrenbo was given every four weeks.

How long does Xtrenbo take to work for multiple myeloma?

In clinical studies of people with newly diagnosed multiple myeloma, Xtrenbo reduced levels of a marker of bone breakdown called uNTx/Cr by about 75 percent within five weeks of treatment. These reductions were maintained through at least 49 weeks of treatment.

Because people respond differently to treatment, there is no set time frame for when someone may notice a difference. Xtrenbo is used to help prevent serious bone problems, such as fractures and other skeletal-related events, in people with multiple myeloma.

What tests or monitoring are needed with Xtrenbo for multiple myeloma?

Your doctor should check your calcium levels during treatment, especially during the first weeks after starting Xtrenbo. Low calcium must be corrected before treatment begins. Calcium, magnesium, and vitamin D may be given as needed.

Before starting Xtrenbo, your doctor should perform an oral exam and may recommend preventive dental care. Your mouth and jaw should be monitored during treatment because a serious jawbone problem called osteonecrosis of the jaw has been reported.

If you can become pregnant, your doctor should check your pregnancy status before starting treatment.