Balversa (Erdafitinib)
FGFR tyrosine kinase inhibitor for advanced urothelial cancer
Quick Facts About Balversa
Key Takeaways About Balversa
- Targeted therapy: Balversa specifically targets cancer cells with FGFR3 gene alterations and is only used after genetic testing confirms these changes
- Regular eye exams required: Central serous retinopathy is a serious risk – monthly eye exams for the first 4 months, then every 3 months
- Phosphate monitoring essential: Blood phosphate levels must be checked regularly, and dietary phosphate intake may need to be limited
- Many drug interactions: Numerous medications can increase or decrease Balversa levels – always inform your doctor of all medicines you take
- Contraindicated in pregnancy: Balversa may harm the unborn child – effective contraception is mandatory during and for 1 month after treatment
What Is Balversa and What Is It Used For?
Balversa (erdafitinib) is a prescription cancer medicine used to treat adults with locally advanced or metastatic urothelial carcinoma (bladder and urinary tract cancer) that has FGFR3 gene alterations and has progressed after immunotherapy. It works by blocking FGFR tyrosine kinases to slow or stop cancer cell growth.
Balversa belongs to a class of medicines called tyrosine kinase inhibitors. Its active ingredient, erdafitinib, specifically targets proteins known as fibroblast growth factor receptor (FGFR) tyrosine kinases. These receptors play a crucial role in cell growth and division. In certain cancers, genetic alterations in the FGFR3 gene cause these receptors to become overactive, driving uncontrolled tumour growth.
Urothelial carcinoma is the most common type of bladder cancer. It arises from the urothelial cells that line the inner surface of the bladder, ureters, and renal pelvis. When this cancer is described as locally advanced, it means it has spread to tissues near the bladder but cannot be surgically removed. Metastatic disease means the cancer has spread to distant parts of the body, such as the lungs, bones, or liver.
Balversa is specifically indicated for patients whose cancer has certain alterations in the FGFR3 gene. Before treatment begins, your oncologist will order a validated genetic test to confirm the presence of these alterations. Only patients with confirmed FGFR3 gene changes are eligible for Balversa treatment. Additionally, Balversa is used when the cancer has worsened during or after at least one line of treatment that included immunotherapy (such as checkpoint inhibitors like pembrolizumab or atezolizumab).
How does erdafitinib work?
Erdafitinib works by selectively inhibiting FGFR1, FGFR2, FGFR3, and FGFR4 enzymes. By blocking these receptors, the drug interrupts the signalling pathways that cancer cells rely on to proliferate and survive. In tumours driven by FGFR3 alterations, this targeted blockade can help slow or halt cancer progression. The mechanism is distinct from chemotherapy, which kills rapidly dividing cells indiscriminately, and from immunotherapy, which enhances the immune system's ability to recognise and attack cancer.
Clinical evidence from the phase 3 THOR trial demonstrated that erdafitinib significantly improved overall survival compared with chemotherapy in patients with FGFR-altered locally advanced or metastatic urothelial carcinoma who had previously received immunotherapy. This landmark study led to the approval of Balversa by both the U.S. Food and Drug Administration (FDA) and the European Medicines Agency (EMA).
Balversa should only be prescribed after a validated test confirms FGFR3 gene alterations in the tumour. Your oncologist will arrange this test before starting treatment. Not all urothelial cancers have these alterations.
What Should You Know Before Taking Balversa?
Before taking Balversa, tell your doctor if you have high phosphate levels, eye problems, are pregnant or could become pregnant. Do not take Balversa if you are allergic to erdafitinib. Regular eye exams and blood tests are required throughout treatment.
Contraindications
Do not take Balversa if you are allergic to erdafitinib or any of the other ingredients in this medicine. The inactive ingredients include croscarmellose sodium, magnesium stearate, mannitol, meglumine, microcrystalline cellulose, and various film-coating agents. If you are unsure about any ingredient, consult your pharmacist.
Warnings and Precautions
Talk to your doctor before using Balversa if you have any of the following conditions or risk factors. Your healthcare team will monitor you closely throughout treatment and may need to adjust your dose or temporarily pause treatment if certain side effects develop.
Eye problems (central serous retinopathy)
Balversa increases the risk of central serous retinopathy (CSR), a condition where fluid accumulates beneath the macula (the central part of the retina at the back of the eye), leading to blurred and distorted vision. The risk of CSR is higher in patients aged 65 years or older.
Before starting treatment, you will undergo a comprehensive eye examination including assessment of your vision, retina, and eye structures. Your doctor will continue to monitor your eyes with examinations monthly for the first 4 months and every 3 months thereafter. If you experience any visual symptoms, an urgent eye examination will be arranged.
- Blurred vision or reduced peripheral (side) vision
- A dark spot in the centre of your visual field
- Distorted central vision where straight lines appear wavy or bent
- Objects appear smaller or farther away than they really are
- Colours appear washed out
- Spots or dots passing through your visual field
- Light flashes or a sensation of looking through a curtain
If CSR develops, your doctor may temporarily pause treatment. Treatment will be permanently discontinued if symptoms do not resolve within 4 weeks or are very severe. Use eye drops or eye gel regularly during treatment to prevent and treat dry eyes.
High phosphate levels (hyperphosphataemia)
Balversa commonly causes elevated blood phosphate levels (hyperphosphataemia), typically occurring within the first few weeks of treatment. Prolonged high phosphate levels can lead to calcification of soft tissues, cutaneous calcinosis (hard lumps or nodules in the skin due to calcium deposits), and calciphylaxis (a rare but serious condition causing painful skin wounds from calcium build-up in blood vessels).
Your doctor will monitor your blood phosphate levels regularly throughout treatment. You may be advised to limit phosphate-rich foods (such as dairy products, nuts, seeds, and processed foods) and avoid medications that could further elevate phosphate levels. Vitamin D supplements are not recommended during Balversa treatment, as they can increase both phosphate and calcium levels. If phosphate levels become too high, your doctor may prescribe phosphate binders or adjust your Balversa dose.
Tell your healthcare provider immediately if you experience painful skin changes, muscle cramps, numbness, or tingling around the mouth – these may be signs of hyperphosphataemia.
Skin changes
You may experience itching, dry or red skin, swelling, peeling or tender skin – particularly on the hands and feet (hand-foot syndrome) – while taking Balversa. To minimise skin problems, check your skin regularly, avoid unnecessary sun exposure, limit excessive use of soap and bathing, use moisturiser regularly, and avoid perfumed products.
Photosensitivity
Balversa can make your skin more sensitive to sunlight, potentially leading to sunburn or skin damage. Take preventive measures when spending time outdoors, including wearing protective clothing and applying broad-spectrum sunscreen.
Nail changes
Nails may separate from the nail bed, surrounding skin may become infected, or nails may become discoloured during treatment. Monitor your nails for signs of infection and practise good nail hygiene. Over-the-counter nail-strengthening treatments may be helpful.
Mucous membrane changes
Dry mouth and mouth sores (stomatitis) are common during Balversa treatment. Maintain good oral hygiene throughout treatment and avoid spicy or acidic foods that may irritate the mouth.
Pregnancy and Breastfeeding
Balversa may harm the unborn child. This medicine should not be used during pregnancy unless your doctor determines it is absolutely necessary. If you are a woman of childbearing potential, your doctor will require a pregnancy test before starting treatment.
Contraception for women: Balversa may reduce the effectiveness of certain hormonal contraceptives. Discuss suitable contraceptive methods with your doctor. Women who could become pregnant must use a highly effective non-hormonal method of contraception during treatment and for at least 1 month after the last dose.
Breastfeeding: Do not breastfeed during treatment with Balversa and for 1 month after the last dose.
Contraception for men: Men must use effective contraception (condoms) during treatment and for 1 month after the last dose. Do not donate or store sperm during treatment and for 1 month after the last dose.
Children and adolescents
Balversa should not be used in children or adolescents, as there is no experience with this medicine in patients under 18 years of age.
Driving and operating machinery
Eye problems have been reported in patients taking Balversa. If your vision is affected, do not drive or use tools or machinery until your vision returns to normal.
How Does Balversa Interact with Other Drugs?
Balversa has significant interactions with many medications. Some drugs reduce its effectiveness (e.g. carbamazepine, rifampicin, phenytoin), while others increase the risk of side effects (e.g. azole antifungals, certain antibiotics). Balversa can also increase levels of other medicines in the body, including blood thinners and digoxin.
Always tell your doctor, pharmacist, or nurse about all medicines you are taking, have recently taken, or might take. Taking Balversa together with certain other medicines can affect how Balversa works and may cause side effects. The interactions below are clinically significant and require careful management by your healthcare team.
Drugs That Reduce Balversa's Effectiveness
The following medicines can decrease the amount of Balversa in your blood, potentially reducing its anti-cancer effect. These are strong CYP3A4 inducers that speed up the breakdown of erdafitinib in the liver:
| Medicine | Common Use | Interaction Type |
|---|---|---|
| Carbamazepine | Epilepsy | Strong CYP3A4 inducer |
| Rifampicin | Tuberculosis | Strong CYP3A4 inducer |
| Phenytoin | Epilepsy | Strong CYP3A4 inducer |
| St. John's Wort | Depression (herbal) | Strong CYP3A4 inducer |
Drugs That Increase Balversa Side Effects
The following medicines can increase the amount of Balversa in your blood, raising the risk of side effects. These are CYP3A4 and CYP2C9 inhibitors that slow the breakdown of erdafitinib:
| Medicine | Common Use | Interaction Type |
|---|---|---|
| Fluconazole | Fungal infections | CYP2C9/CYP3A4 inhibitor |
| Itraconazole | Fungal infections | Strong CYP3A4 inhibitor |
| Ketoconazole | Fungal infections | Strong CYP3A4 inhibitor |
| Posaconazole | Fungal infections | Strong CYP3A4 inhibitor |
| Voriconazole | Fungal infections | Strong CYP3A4 inhibitor |
| Clarithromycin | Bacterial infections | Strong CYP3A4 inhibitor |
| Ritonavir | HIV treatment | Strong CYP3A4 inhibitor |
| Amiodarone | Heart rhythm disorders | CYP3A4 inhibitor |
| Piperine | Dietary supplement | CYP3A4 inhibitor |
Drugs Whose Levels Are Increased by Balversa
Balversa can increase the amount of the following medicines in your blood, raising the risk of their side effects. Your doctor may need to adjust dosages of these medications if you are taking them concurrently:
| Medicine | Common Use | Risk |
|---|---|---|
| Midazolam | Seizures, sedation | Increased sedation |
| Hormonal contraceptives | Birth control | Altered effectiveness |
| Colchicine | Gout | Increased toxicity |
| Digoxin | Heart conditions | Increased cardiac effects |
| Dabigatran | Blood thinner | Increased bleeding risk |
| Apixaban | Blood thinner | Increased bleeding risk |
Do not take Balversa with grapefruit or Seville oranges – whether eating the fruit, drinking juice, or taking supplements containing their extracts. These can increase the amount of erdafitinib in your blood, raising the risk of serious side effects.
What Is the Correct Dosage of Balversa?
The recommended starting dose of Balversa is 8 mg once daily by mouth. After approximately 2 weeks, based on blood phosphate levels and tolerability, the dose may be increased to 9 mg daily or reduced depending on side effects. Tablets should be swallowed whole, with or without food, at the same time each day.
Always take Balversa exactly as your doctor or pharmacist has told you. Your oncologist will determine the appropriate dose based on your individual response and any side effects you experience.
Adults
Starting Dose
The recommended starting dose is 8 mg once daily taken by mouth. You may need to take a combination of tablets to achieve this dose (for example, one 5 mg tablet and one 3 mg tablet, or two 4 mg tablets).
Dose Adjustment After 2 Weeks
After approximately 2 weeks of treatment, your doctor will take a blood test to check your phosphate levels. Based on these results and your tolerability:
- The dose may be increased to 9 mg daily if tolerated
- The dose may be reduced if you experience significant side effects such as mouth sores, hand-foot syndrome, nail separation, or high phosphate levels
- Treatment may be temporarily paused or permanently stopped depending on the severity of adverse effects
How to Take Balversa
- Swallow the tablets whole – do not crush, break, or chew them
- You can take this medicine with or without food
- Try to take it at the same time each day to help you remember
- If you vomit after taking a dose, do not take a replacement dose. Take your next dose at the usual time the following day
Children
Balversa is not indicated for use in children and adolescents under 18 years of age. There are no clinical data on the safety or efficacy of erdafitinib in paediatric patients.
Elderly Patients
No specific dose adjustments are required for elderly patients based on age alone. However, patients aged 65 and older have a higher risk of developing central serous retinopathy (CSR) and may require more frequent monitoring. Dose adjustments are based on individual tolerability, side effects, and blood test results rather than age.
Missed Dose
If you forget to take a dose, take it as soon as you remember on the same day. Take your normal dose the next day as usual. Do not take a double dose to make up for a forgotten one.
Overdose
If you take too much Balversa, contact your doctor or seek emergency medical attention immediately. There is no specific antidote for erdafitinib overdose. Treatment is supportive and based on the symptoms experienced.
Do not stop taking Balversa unless your doctor tells you to. Discontinuing treatment without medical supervision could allow the cancer to progress. If you have concerns about side effects or the treatment, discuss them with your oncologist who can advise on the best course of action.
What Are the Side Effects of Balversa?
The most common side effects of Balversa include high blood phosphate levels, eye problems (central serous retinopathy), nail and skin changes, mouth sores, diarrhoea, decreased appetite, taste changes, weight loss, fatigue, and dry eyes. Tell your doctor immediately about any vision changes, painful skin changes, or unusual symptoms.
Like all medicines, Balversa can cause side effects, although not everybody gets them. Some side effects can be serious and require immediate medical attention. Below is a comprehensive overview of reported side effects, organised by frequency.
Most Important Side Effects
The following side effects are considered the most clinically significant and require prompt attention:
Central Serous Retinopathy (CSR)
- Blurred vision or reduced peripheral vision
- Dark spot in the centre of your visual field
- Distorted vision (straight lines appear wavy)
- Objects appear smaller or farther away
- Washed-out colours, floaters, or light flashes
Hyperphosphataemia (High Blood Phosphate)
- Elevated phosphate levels detected in blood tests
- May cause calcium deposits in soft tissues
- Painful skin changes, muscle cramps
- Numbness or tingling around the mouth
Nail Changes
- Nails separating from the nail bed (onycholysis)
- Infection of skin around the nail (paronychia)
- Poor nail growth or nail discolouration
Skin Changes
- Redness, swelling, peeling or tender skin on hands and feet (hand-foot syndrome)
- Hair loss (alopecia)
- Dry skin
Mucous Membrane Changes
- Mouth sores (stomatitis)
- Dry mouth
Complete Side Effects by Frequency
Very Common
- Diarrhoea
- Decreased appetite
- Taste changes (metallic, sour, or bitter taste – dysgeusia)
- Weight loss
- Constipation
- Nausea and vomiting
- Abdominal pain
- Dry eyes
- Weakness and severe fatigue
- Low blood sodium (hyponatraemia)
- Elevated blood creatinine
- Elevated liver enzymes (ALT and AST)
- Low red blood cell count (anaemia)
- Nosebleeds
Common
- Painful nails, cracked or broken nails
- Very dry, cracked, thickened, or flaking skin
- Itchy skin or eczema-like rash
- Abnormal skin growth or appearance
- Rash
- Dry or inflamed eyes (conjunctivitis)
- Corneal ulcers or inflammation
- Cloudy lens (cataract)
- Red and swollen eyelids, watery eyes
- High blood calcium, low blood phosphate
- Nasal dryness
- Indigestion (dyspepsia)
- Sudden decrease in kidney function
- High parathyroid hormone levels
- Kidney failure or impaired kidney function
- Liver damage (hepatic cytolysis)
- Abnormal liver function, high bilirubin
Uncommon
- Bleeding under the nail
- Nail discomfort or pain
- Skin thinning
- Redness of the palms
- Dryness of mucous membranes (nose, mouth, eyes, vagina)
- Calciphylaxis (calcium build-up in blood vessels causing ulcers and serious infections)
Contact your doctor or seek emergency care immediately if you experience any of the following while taking Balversa:
- Any changes in your vision (blurred vision, dark spots, distorted lines)
- Painful skin changes, sores, or hard lumps under the skin
- Muscle cramps, numbness, or tingling around the mouth
- Signs of severe infection (high fever, chills, difficulty breathing)
- Signs of liver problems (yellowing of skin or eyes, dark urine, severe fatigue)
How Should You Store Balversa?
Store Balversa out of sight and reach of children. No special storage conditions are required. Do not use after the expiry date printed on the carton and bottle. Do not use if the packaging is damaged or shows signs of tampering.
Balversa film-coated tablets are supplied in child-resistant plastic bottles. Each carton contains one bottle with either 28, 56, or 84 tablets depending on the strength. Follow these storage guidelines to ensure the medicine remains effective:
- Keep out of sight and reach of children at all times
- No special storage conditions – store at room temperature
- Do not use after the expiry date ("EXP") printed on the carton and bottle – the expiry date refers to the last day of that month
- Do not use if the packaging is damaged or shows signs of tampering
- Do not dispose of medicines via wastewater or household waste – ask your pharmacist how to dispose of medicines no longer required, to help protect the environment
What Does Balversa Contain?
Balversa tablets contain erdafitinib as the active ingredient (3 mg, 4 mg, or 5 mg per tablet). Inactive ingredients include croscarmellose sodium, magnesium stearate, mannitol, meglumine, microcrystalline cellulose, and film-coating agents. The tablets contain less than 1 mmol sodium per dose.
Active ingredient
Each film-coated tablet contains either 3 mg, 4 mg, or 5 mg of erdafitinib.
Inactive ingredients
Tablet core: Croscarmellose sodium, magnesium stearate (E572), mannitol (E421), meglumine, and microcrystalline cellulose (E460).
Film coating (Opadry amb II): Glycerol monocaprylocaprate type I, partially hydrolysed poly(vinyl alcohol), sodium lauryl sulfate, talc, titanium dioxide (E171), yellow iron oxide (E172), red iron oxide (E172) (4 mg and 5 mg tablets only), black iron oxide (E172) (5 mg tablets only).
Tablet appearance
| Strength | Colour | Shape | Markings |
|---|---|---|---|
| 3 mg | Yellow | Round, biconvex | "3" on one side, "EF" on the other |
| 4 mg | Orange | Round, biconvex | "4" on one side, "EF" on the other |
| 5 mg | Brown | Round, biconvex | "5" on one side, "EF" on the other |
Balversa contains less than 1 mmol (23 mg) sodium per dose, meaning it is essentially sodium-free. This is relevant for patients on a controlled sodium diet.
Frequently Asked Questions About Balversa
Balversa (erdafitinib) is used to treat adults with locally advanced or metastatic urothelial carcinoma (bladder and urinary tract cancer) that has specific FGFR3 gene alterations and has progressed after prior immunotherapy treatment. It belongs to the class of FGFR tyrosine kinase inhibitors and works by blocking the growth signals that cancer cells rely on. A genetic test must confirm FGFR3 alterations before treatment can begin.
The most serious side effects include central serous retinopathy (CSR), which can cause vision problems including blurred vision, dark spots, and distorted vision. Hyperphosphataemia (high blood phosphate) is very common and can lead to calciphylaxis, a rare but potentially life-threatening condition. Other serious effects include severe skin reactions (hand-foot syndrome), nail changes, kidney problems, and liver damage. Regular monitoring with eye exams and blood tests is essential throughout treatment.
Yes, Balversa can be taken with or without food. However, you must avoid grapefruit and Seville oranges (including juice and supplements containing their extracts) as these can significantly increase the amount of erdafitinib in your blood. Swallow the tablets whole without crushing or chewing. Try to take your dose at the same time each day to maintain consistent blood levels.
The duration of Balversa treatment depends on how well the cancer responds and how well you tolerate the medicine. Treatment typically continues for as long as it provides clinical benefit and the side effects remain manageable. Your oncologist will regularly assess your response through imaging scans and blood tests. Do not stop taking Balversa without discussing it with your doctor first, even if you feel well, as this could allow the cancer to progress.
No. Balversa may harm the unborn child and should not be used during pregnancy. Women of childbearing potential must take a pregnancy test before starting treatment and use highly effective non-hormonal contraception during treatment and for at least 1 month after the last dose. Note that Balversa may reduce the effectiveness of hormonal contraceptives. Men must also use condoms during treatment and for 1 month after the last dose, and should not donate or store sperm during this period. Breastfeeding is not recommended during treatment and for 1 month after the last dose.
All information is based on the approved Summary of Product Characteristics (SmPC) from the European Medicines Agency (EMA), FDA prescribing information, clinical trial data from the THOR phase 3 study published in the New England Journal of Medicine (2023), NCCN Clinical Practice Guidelines for Bladder Cancer, and ESMO Clinical Practice Guidelines. All medical claims are evidence-based and reviewed by board-certified oncology specialists.
References
- Loriot Y, Necchi A, Park SH, et al. Erdafitinib in Locally Advanced or Metastatic Urothelial Carcinoma. N Engl J Med. 2023;389(15):1355-1366. doi:10.1056/NEJMoa2308849
- European Medicines Agency. Balversa (erdafitinib) – Summary of Product Characteristics. EMA/2024. Available at: ema.europa.eu/balversa
- U.S. Food and Drug Administration. BALVERSA (erdafitinib) prescribing information. FDA/2024.
- National Comprehensive Cancer Network (NCCN). Clinical Practice Guidelines in Oncology: Bladder Cancer. Version 3.2025.
- Powles T, Bellmunt J, Comperat E, et al. Bladder cancer: ESMO Clinical Practice Guideline for diagnosis, treatment and follow-up. Ann Oncol. 2024;35(2):159-174.
- Siefker-Radtke AO, Necchi A, Park SH, et al. Erdafitinib in locally advanced or metastatic urothelial carcinoma (LUC): Results from the phase 2 BLC2001 study. J Clin Oncol. 2022;40(4_suppl):435.
- World Health Organization. WHO Model List of Essential Medicines – 23rd List. Geneva: WHO; 2023.
Medical Editorial Team
This article has been written, fact-checked, and medically reviewed by the iMedic Medical Editorial Team in accordance with our editorial standards.
iMedic Medical Content Team
Specialists in oncology and clinical pharmacology
iMedic Medical Review Board
Board-certified physicians
Level 1A – Based on systematic reviews and meta-analyses of RCTs
EMA SmPC, FDA PI, NCCN, ESMO Clinical Practice Guidelines
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