Balversa (erdafitinib)

Reviewed by: HU Medical Review Board | Last reviewed: April 2023

Balversa (erdafitinib) is a kinase inhibitor that may be a treatment option for adult patients with certain forms of locally advanced or metastatic bladder cancer. It is recommended for use in select cases that have:1

  • Susceptible fibroblast growth factor receptor FGFR3 or FGFR2 genetic alterations, and
  • Gotten worse during or after treatment with certain chemotherapy that contains platinum

What is an FGFR inhibitor?

Erdafitinib is an oral pan-fibroblast growth factor receptor (FGFR) tyrosine kinase inhibitor. FGFRs are a family of receptor tyrosine kinases which may be genetically altered in certain cases of bladder cancer, and treatments that target these genetic alterations can help treat bladder cancer in some patients.1

How does erdafitinib work?

FGFR, fibroblast growth factor receptors, are thought to have a role in cancer growth and development in some types of cancer cells. Erdafitinib, an FGFR kinase inhibitor, blocks the action of FGFR. This could slow down or stop tumor cells dependent on this growth factor to replicate. Around 20 percent of recurring or refractory bladder cancers have the FGFR mutation which may respond to treatment with an FGFR inhibitor.1,2

What are the possible side effects of erdafitinib?

The most common side effects of erdafitinib include:1

  • Fatigue
  • Change in kidney or liver function
  • Constipation or diarrhea
  • Dry mouth and/or mouth sores
  • Stomach pain, nausea, decreased appetite
  • Increased levels of phosphate or decreased levels of sodium in the blood
  • Changes in nail appearance
  • Dry skin, dry eyes
  • Low red blood cell counts (anemia)
  • Hair loss
  • Muscle pain
  • Hand-foot syndrome: the swelling, peeling, redness, or tenderness of the hands and feet
  • Taste changes

If you are pregnant, plan to become pregnant, or are breastfeeding or plan to breastfeed, talk with your doctor. Erdafitinib can cause harm to a developing fetus and should not be taken by people who are pregnant.1

While taking erdafitinib, if you or your partner can become pregnant, you should both use contraceptives during treatment and for a period of time after completing treatment (patients should discuss appropriate birth control methods, and how long they need to use them, with their doctor). Do not breastfeed during erdafitinib treatment and for a period of time following the final dose (patients should discuss breastfeeding considerations with their doctor).1

These are not all the possible side effects of erdafitinib. Talk to your doctor about what to expect when taking erdafitinib. You also should call your doctor if you have any changes that concern you when takingerdafitinib.

Things to know about erdafitinib

Erdafitinib is the first FGFR kinase inhibitor to receive approval from the US Food and Drug Administration (FDA). When the FDA approved erdafitinib, it simultaneously approved a companion diagnostic tool to help identify the subgroup of people most likely to benefit from the drug. That’s designed to create a more personalized treatment approach.3

The diagnostic kit is QIAGEN therascreen®. It detects the presence of FGFR in tumor tissue of people with metastatic urothelial cancer. If present, the patient may be a candidate for treatment with erdafitinib.1-3

Erdafitinib and eye problems

Erdafitinib can cause ocular disorders (problems with your eyes), including central serous retinopathy (CSR) that’s characterized by retinal pigment epithelial detachment (RPED) resulting in visual field defects. Monthly eye exams should be performed during the first 4 months of treatment with erdafitinib, and every 3 months afterward. Eye exams should include:1,3

  • Evaluation of visual acuity – how well you see at various distances
  • Slit lamp examination – a microscope with a bright light used to look at different structures at the front of and inside the eye
  • Fundoscopy – a magnifying lens and light used to examine the fundus of the eye, including the back of the inside of the eye, the retina, and the optic nerve
  • OCT optical coherence tomography – a non-invasive diagnostic technique to look at the retina

Talk to your healthcare provider immediately if you notice changes in vision.


Erdafitinib can also cause hyperphosphatemia, an abnormally high serum phosphate concentration (greater than 4.5 mg/dL). It can be caused by increased phosphate intake, decreased phosphate excretion, or associated with an underlying disease such as bladder cancer that can have increased phosphate values.1

Before beginning treatment for bladder cancer, tell your doctor about all your health conditions and any other drugs, vitamins, or supplements you are taking. This includes over-the-counter drugs.

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