Balversa (Erdafitinib) for FGFR3 Bladder Cancer: What to Know

Has Anyone Tested Your Bladder Cancer for FGFR3?

Written By: Nitin Goswami, Senior Medical Content Writer  |  Medically Reviewed By: Shilpi Banerjee, Registered Pharmacist (M.Pharm)

Treatment for advanced bladder cancer often includes chemotherapy and an immunotherapy. But when those stop working, there's one question that can open a different door: has your tumor been tested for an FGFR3 change?

If the answer is yes, and the test found one, a tablet called Balversa (erdafitinib) may be an option. It's taken at home, it isn't chemotherapy, and it was built for tumors driven by FGFR3. It also comes with a few habits worth knowing about before day one, mostly around phosphate, your eyes, and your nails.

The U.S. FDA gave Balversa its current (traditional) approval on January 19, 2024, for adults with locally advanced or metastatic urothelial carcinoma, the most common type of bladder cancer, that has a susceptible FGFR3 alteration and has progressed after at least one earlier treatment. This guide covers the test, what the trials showed, what the first weeks look like, and the questions to bring to your oncologist.

Balversa at a Glance

First, the Test: Is Your Tumor FGFR3-Altered?

What FGFR3 Is

FGFR3 is a receptor on the surface of cells that helps control growth. In some bladder cancers the FGFR3 gene has a change, either a mutation or a fusion with another gene, that keeps the growth signal switched on. Balversa is designed to block that signal.

• In the main trial, among patients whose tumors carried a qualifying change, 81% had FGFR3 mutations, 17% had fusions, and 2% had both
• Only tumors with a susceptible FGFR3 change qualify, so the test result, not the type of bladder cancer alone, decides whether Balversa can be used

How the Testing Works

• The FGFR3 change has to be confirmed in a tumor specimen before treatment starts, using an FDA-approved companion diagnostic
• In the main trial, 75% of patients were tested with the QIAGEN therascreen FGFR RGQ RT-PCR kit, and the other 25% with local next-generation sequencing (NGS) tests
• If you've had a biopsy or surgery in the past, ask whether that tissue can be tested, so you don't need a new procedure just for this

Who Balversa Is For

Balversa is approved for adults with locally advanced or metastatic urothelial carcinoma who have a susceptible FGFR3 alteration and whose disease has progressed on or after at least one earlier line of systemic therapy.

One Important Limit

Balversa isn't recommended for people who are eligible for a PD-1 or PD-L1 immunotherapy but haven't yet received one. That limit comes from a second trial, which we'll explain below.

Bladder Cancer in Numbers

Statistics can't tell you what will happen to you. They do show how common this diagnosis is, and how much research sits behind the options you're being offered. Every figure names its source and year.

How Many People Are Affected?

• Worldwide (GLOBOCAN 2024, WHO/IARC): 635,264 new cases and 227,626 deaths in a year. It's the 8th most common cancer (3.1% of all cancers)
• India (GLOBOCAN 2024): 25,980 new cases and 9,687 deaths a year, which makes up 1.7% of the country's cancers
• United States (SEER, 2026 estimate): 84,530 new cases and 17,870 deaths, with an estimated 763,031 people living with bladder cancer in 2023
• The main type: urothelial carcinoma, also called transitional cell carcinoma, is by far the most common type of bladder cancer (American Cancer Society)

India's figures are modelled from regional cancer registries rather than counted nationwide, so treat them as a reliable ballpark, not an exact head-count.

Who Gets It?

• Bladder cancer is more common in men than in women. In the US the rate is 31.0 new cases per 100,000 men versus 7.6 per 100,000 women (SEER)
• The median age at diagnosis is 73 in the US, and about 2.1% of people will be diagnosed at some point in their lives (SEER)

Why Stage Matters

• Half of US bladder cancers (50%) are found at the very earliest, in situ stage, 34% are localized, 7% have reached nearby lymph nodes, and 6% have already spread to distant organs (SEER, 2016–2022)
• Five-year survival is about 98% for in situ disease, 73% when localized, 42% when regional, and 10% once it has spread to distant organs. Across all stages it's 79%

These are relative survival figures, which compare people with the cancer to the general population, and they describe large groups rather than any one person. The gap between early and distant disease is the main reason treatments for advanced bladder cancer are studied so closely.

How Erdafitinib Works

Balversa is a fibroblast growth factor receptor (FGFR) kinase inhibitor. In a tumor with an FGFR3 change, the receptor keeps telling the cell to grow and divide. Erdafitinib blocks that signal, which is why it's matched to tumors that carry the change and not used for every bladder cancer.

What the Trials Found

THOR Cohort 1: Erdafitinib Versus Chemotherapy

This trial enrolled 266 people with advanced urothelial carcinoma and an FGFR3 change whose cancer had progressed after one or two earlier treatments, including a PD-1 or PD-L1 immunotherapy. Half received Balversa (136 patients) and half received chemotherapy, either docetaxel or vinflunine (130 patients) (New England Journal of Medicine, 2023).

How Long People Lived

• Median overall survival was 12.1 months with Balversa versus 7.8 months with chemotherapy, a hazard ratio for death of 0.64, or roughly a third lower risk of death
• Median progression-free survival was 5.6 months versus 2.7 months (hazard ratio 0.58)

How Many Tumors Shrank

• A confirmed response occurred in 35.3% of people on Balversa versus 8.5% on chemotherapy
• Complete responses were seen in 5.1% versus 0.8%

How Well People Tolerated It

• Grade 3 or 4 treatment-related side effects were about equally common in both groups: 45.9% with Balversa and 46.4% with chemotherapy
• Even so, the side effects are different and need active management. According to the FDA label, 72% of patients on Balversa had a dose interruption, 69% had a dose reduction, and 14% stopped it permanently

THOR Cohort 2: Why the Limit Exists

A second group in the same trial looked at people who had had one earlier treatment but had never received a PD-1 or PD-L1 immunotherapy. Balversa was compared with pembrolizumab in 351 patients (Annals of Oncology, 2024).

• Overall survival was about the same: 10.9 months with Balversa versus 11.1 months with pembrolizumab (hazard ratio 1.18, which was not a statistically significant difference)
• Tumors responded more often with Balversa (40.0% versus 21.6%), but responses lasted a median of 4.3 months versus 14.4 months
• Grade 3 or 4 side effects occurred in 64.7% versus 50.9%

Because Balversa didn't extend survival compared with pembrolizumab in this group, the FDA added the limit that it isn't recommended for people who are eligible for a PD-1 or PD-L1 immunotherapy and haven't had one.

So How Much Does It Help?

In people whose cancer had already progressed on immunotherapy, Balversa gave a median of about 4.3 extra months of survival compared with chemotherapy. That's a meaningful gain for a difficult situation, and it isn't a cure. Medians are midpoints, so some people do better and some do worse. Whether it's the right choice for you depends on your health, your earlier treatments, and how you feel about the side effects, and that's a decision to make with your oncologist.

Starting Balversa: The First Three Weeks Matter

The Starting Dose and the Day 14 to 21 Check

• You start at 8 mg once a day (two 4 mg tablets)
• Between day 14 and day 21, your blood phosphate level is checked
• If your phosphate is below 9.0 mg/dL and you haven't had eye problems or side effects of grade 2 or higher, the dose goes up to 9 mg once a day (three 3 mg tablets)
• After that, phosphate is monitored monthly

The Everyday Basics

• Swallow the tablets whole, with or without food
• Missed a dose? Take it as soon as you can the same day, then go back to your usual schedule the next day. Don't take extra tablets to make up for it
• Vomited after a dose? Skip it and take your next dose the next day
• Storage: at room temperature, 20°C to 25°C (68°F to 77°F)
• Treatment length: until the disease progresses or side effects become unacceptable. In the trials, the median treatment time was 4.8 months

If You Need a Lower Dose

• From 9 mg, the steps down are 8 mg, 6 mg, 5 mg, then 4 mg
• From 8 mg, the steps down are 6 mg, 5 mg, then 4 mg
• If you can't tolerate 4 mg, Balversa is stopped

Living With Balversa: Phosphate, Eyes, Nails and More

Phosphate

High phosphate in the blood is expected with this medicine. It's a direct effect of how erdafitinib works, so it's monitored closely and managed rather than avoided.

How Common Is It?

• Raised phosphate occurred in 73% of patients, and the median time to onset was 16 days after starting
• 24% of patients received a phosphate binder
• In rare cases, long-term high phosphate can lead to calcium deposits in soft tissues. Vascular calcification was seen in 0.2% of patients

What You Can Do

Watch Your Phosphate Intake

The label advises limiting dietary phosphate to 600 to 800 mg a day. Ask your care team or a dietitian to help you translate that into meals, since phosphate hides in many foods.

Avoid Anything That Shifts Phosphate Early On

During the first weeks, until the day 14 to 21 check, avoid medicines that can change your phosphate level, so the check reflects Balversa alone.

If Your Level Goes High

• Above 7.0 mg/dL: your doctor may add a phosphate binder, taken with food
• 9 to 10 mg/dL: Balversa is paused and your level is rechecked weekly until it falls below 7, then it's restarted at the same dose
• Above 10 mg/dL: it's paused until it falls below 7, then may restart at the next lower dose. If it stays that high for more than 2 weeks, Balversa is stopped permanently

Know the Warning Signs

Tell your team right away about painful skin lesions, muscle cramps, or numbness or tingling around the mouth.

Your Eyes

How Common Is It?

• A retinal problem called central serous retinopathy (CSR), a buildup of fluid under the retina, occurred in 22% of patients, with a median onset of 46 days
• Dry eye symptoms occurred in 26% of patients
• Among patients who developed CSR, 40% needed a dose interruption, 56% needed a dose reduction, and 2.9% of all patients stopped Balversa because of it. In 41% of these patients the problem was still present at the last evaluation

What the Monitoring Looks Like

• You'll have an eye examination every month for the first 4 months, then every 3 months after that, and urgently at any time you notice vision changes
• The exam covers visual acuity, a slit lamp exam, a look at the back of the eye, and optical coherence tomography (OCT)
• To prevent dry eyes, the label advises artificial tears or lubricating eye gels or ointments frequently, at least every 2 hours while you're awake

If Your Vision Changes

Contact your care team immediately. If CSR is found, Balversa is paused and you have an eye evaluation within 2 weeks. If it improves within 14 days, treatment can restart at the same dose. If not, it stays paused until it improves and may restart at a lower dose. Permanent discontinuation is considered if the problem recurs or hasn't improved after 4 weeks of pausing treatment.

Nails, Skin and Mouth

• Nail changes affected 70% of patients on Balversa in the trial (12% at grade 3 or 4), compared with 5% on chemotherapy
• Hand-foot skin reaction affected 30% (10% at grade 3 or 4), dry skin 27%, and hair thinning 25%
• Mouth sores (stomatitis) affected 56% (10% at grade 3 or 4), and dry mouth 39%
• Tell your team if skin, mouth, or nail problems get worse or become hard to live with. Nail problems and mouth sores were among the most common reasons for dose changes

The Other Common Side Effects

• Diarrhea: 63%
• Altered taste (dysgeusia): 30%
• Fatigue: 29%
• Decreased appetite: 27%
• Constipation: 27%
• Weight loss: 22%

Overall, serious side effects occurred in 41% of patients on Balversa, and 4.4% had fatal adverse reactions.

Medicines That Interact

• Moderate CYP2C9 inhibitors or strong CYP3A4 inhibitors can raise Balversa levels, so alternatives are considered or you're monitored closely
• Strong CYP3A4 inducers should be avoided, and if a moderate CYP3A4 inducer is needed at the start of treatment, the dose is 9 mg
• If you take a medicine with a narrow safety margin that moves through the body via P-gp, it should be taken at least 6 hours before or after Balversa
• Tell your oncologist about everything you take, including supplements and herbal products

Pregnancy and Breastfeeding

• Balversa can cause fetal harm. Women who could become pregnant, and men whose partners could become pregnant, should use effective contraception during treatment and for one month after the last dose
• Breastfeeding isn't advised during treatment and for one month after the last dose
• The label also notes that Balversa may impair fertility in females of reproductive potential

Questions Worth Taking to Your Next Appointment

You don't have to remember everything here. A few questions to start the conversation:

• Has my tumor been tested for FGFR3, and which kind of change did it find?
• Have I already had a PD-1 or PD-L1 immunotherapy, and how does that affect my options?
• When is my day 14 to 21 phosphate check, and who will manage my diet?
• Who will do my regular eye examinations?
• Which side effects should make me call you the same day?
• What happens if I need a lower dose?

Getting Balversa in India

As of currently available public information, Balversa is not commercially marketed in India. It's a prescription-only medicine, but it can be imported legally for an individual patient through a Named Patient Program, which brings in a medicine not yet registered in India for a specific patient, in that patient's name. In practice you'll need:

• A valid prescription from a qualified doctor
• Your diagnostic reports, including confirmation of the FGFR3 alteration
• Patient ID proof issued by the Government of India

The Balversa product page explains the process, and our oncology access program covers other cancer medicines on the same pathway.

Have Your Reports Handy? Let's Look at Your Options Together

Whether Balversa fits comes down to your FGFR3 result and your treatment history. Send our team your test report and your oncologist's recommendation, and we'll explain what the access process would involve. There's no cost and no obligation. Start the conversation here.

The Short Version

• Balversa (erdafitinib) is a once-daily FGFR kinase inhibitor tablet, approved by the FDA on January 19, 2024 for advanced urothelial carcinoma with a susceptible FGFR3 alteration after at least one earlier treatment.
• Your tumor has to be tested for FGFR3 with an FDA-approved test, and it isn't recommended for people who are eligible for a PD-1 or PD-L1 immunotherapy and haven't had one.
• In the THOR trial, median survival was 12.1 months versus 7.8 months with chemotherapy, and 35.3% of tumors responded versus 8.5%.
• Phosphate is checked between day 14 and 21, and a phosphate-limited diet is part of the plan. Eye exams are monthly for 4 months, then every 3 months.
• Nail problems (70%), mouth sores (56%), and diarrhea (63%) are common, and most people need a dose adjustment along the way.
• Contraception is needed during treatment and for one month after the last dose.
• Balversa can be accessed through a Named Patient Program with a doctor's prescription and your FGFR3 report.

Frequently Asked Questions

Is Balversa chemotherapy?

No. Chemotherapy attacks fast-dividing cells throughout the body. Balversa is a targeted tablet that blocks the FGFR signal in tumors that carry a specific FGFR3 change.

Do I need to be tested before I can take it?

Yes. A susceptible FGFR3 alteration has to be confirmed in a tumor specimen using an FDA-approved test. Without that result, Balversa isn't the right medicine.

Why is phosphate such a big deal?

Rising phosphate is a direct effect of how erdafitinib works. It occurred in 73% of patients, and it can lead to calcium deposits in tissues if it stays high. That's why your level is checked between day 14 and 21 and every month afterward, and why the dose is adjusted by it.

Can I still wear contact lenses?

Ask your ophthalmologist. Eye problems are common with Balversa, so regular exams are built into treatment. Follow your eye specialist's advice on lenses, especially if you notice any eye symptoms.

What if my vision suddenly changes?

Call your care team straight away and arrange an eye evaluation. Central serous retinopathy is a known side effect, and treatment is paused while it's assessed.

How long will I be on treatment?

Until the disease progresses or side effects become unacceptable. In the studies, the median treatment time was 4.8 months, though some people stayed on much longer.

How do I get Balversa in India?

Through a regulated Named Patient Program, which imports the medicine in the patient's own name with a valid prescription from a qualified doctor, your diagnostic reports including the FGFR3 result, and Government of India ID proof.

Is it safe to order it from an online pharmacy or a seller abroad?

Please be careful. Cancer medicines sold outside regulated channels can be counterfeit, expired, or stored badly, and a tablet that looks right tells you nothing about what's inside it. Named Patient Program sources Balversa from reliable global channels against a valid doctor's prescription, with pharmacist checks, temperature-controlled shipping, and batch traceability, so what reaches you can be traced back to its source.

Every bladder cancer journey looks a little different, and the right next step depends on your test results, your earlier treatments, and how you're feeling. Use this page to prepare better questions, and let your oncologist make the final call.

References

1. U.S. Food and Drug Administration. FDA Approves Erdafitinib for Locally Advanced or Metastatic Urothelial Carcinoma, January 19, 2024.
2. DailyMed (National Library of Medicine). BALVERSA (erdafitinib) Prescribing Information.
3. Loriot Y, et al. Erdafitinib or Chemotherapy in Advanced or Metastatic Urothelial Carcinoma (THOR), New England Journal of Medicine 2023;389.
4. Siefker-Radtke AO, et al. Erdafitinib versus Pembrolizumab in Pretreated Patients with Advanced or Metastatic Urothelial Cancer with Select FGFR Alterations: Cohort 2 of the Randomized Phase III THOR Trial, Annals of Oncology 2024;35.
5. Maguire WF, et al. FDA Approval Summary: Erdafitinib for FGFR3-Altered Locally Advanced or Metastatic Urothelial Carcinoma, Clinical Cancer Research 2026.
6. National Cancer Institute SEER Program. Cancer Stat Facts: Bladder Cancer.
7. American Cancer Society. What Is Bladder Cancer?
8. International Agency for Research on Cancer (WHO). GLOBOCAN 2024: World Fact Sheet.
9. International Agency for Research on Cancer (WHO). GLOBOCAN 2024: India Fact Sheet.