No Waiting for BCG Failure: Durvalumab Approval in High-Risk Bladder Cancer
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FDA Approves Durvalumab + BCG for High-Risk Non-Muscle-Invasive Bladder Cancer: A 40-Year Standard Is Being Strengthened
BCG Was One of Bladder Cancer's Oldest and Most Effective Immunotherapies; It Is Now Being Combined with Modern Immunotherapy
Non-muscle-invasive bladder cancer accounts for a substantial proportion of bladder cancers. In this disease group, the tumor has not invaded the bladder's muscle layer, but the high-risk subgroup has a significant risk of recurrence and progression to muscle-invasive disease. The aim of treatment is therefore not only to remove the visible tumor, but to prevent new high-grade recurrences and muscle invasion within the bladder.
The conventional treatment for high-risk NMIBC is intravesical BCG induction and maintenance after transurethral resection of bladder tumor (TURBT). BCG is actually a live attenuated bacterial vaccine developed against tuberculosis; when administered into the bladder, it stimulates a local immune response and creates an immune-mediated attack on tumor cells. It has been one of the foundational standards in high-risk NMIBC for more than 40 years.
However, BCG is not perfect. Some patients develop early recurrence, some become unresponsive to BCG and others face radical cystectomy because of disease progression. The fundamental question for years has therefore been: Can the local immune response generated by BCG be strengthened with modern immune checkpoint inhibitors? The POTOMAC trial and FDA approval are among the first major phase 3 answers to say “yes” clinically.
Why Does Durvalumab + BCG Make Biological Sense?
BCG generates local immune activation within the bladder. This activation can bring tumor cells to the immune system's attention, but the tumor microenvironment may suppress the immune response through the PD-1/PD-L1 axis. Durvalumab is an immune checkpoint inhibitor that targets PD-L1. In theory, PD-L1 blockade can turn the immune inflammation initiated by BCG into a more effective and longer-lasting antitumor response.
The new approval therefore means more than adding a drug: it brings the concept of “local immunotherapy + systemic immune checkpoint blockade” into clinical practice in NMIBC.
Who Is It Approved For?
The FDA approval covers BCG-naiveadults, meaning those who have not previously received BCG treatment, with high-risk non-muscle-invasive bladder cancer . This is a very important distinction: durvalumab + BCG was approved not for use after BCG failure, but during the high-risk period when BCG is given for the first time.
In POTOMAC, high-risk NMIBC was defined by T1 tumors, grade 3 / high-grade tumors, carcinoma in situ (CIS), or the presence of multiple, recurrent and large tumors. All patients entered the trial after TURBT.
Patient group
BCG-naive adults with high-risk non-muscle-invasive bladder cancer.
Treatment backbone
Durvalumab 1.500 mg (one thousand five hundred milligrams) every 4 weeks for 13 cycles, together with BCG induction and maintenance.
Supporting trial
POTOMAC: a randomized, open-label, multicenter phase 3 trial with a total of 1.018 patients.
How Was POTOMAC Designed?
POTOMAC was a three-arm, 1:1:1 randomized, open-label, multicenter phase 3 trial. Patients were assigned to three strategies: durvalumab + BCG induction and maintenance, BCG induction and maintenance alone, or an additional investigational combination regimen. The comparison decisive for FDA approval was between durvalumab + BCG induction/maintenance and BCG induction/maintenance alone .
| Arm | Treatment | BCG use | Durvalumab use | Clinical meaning |
|---|---|---|---|---|
| Experimental arm | Durvalumab + BCG | Induction + maintenance | 1.500 mg (one thousand five hundred milligrams), every 4 weeks, 13 cycles | A strengthened combination of modern systemic immunotherapy and conventional intravesical BCG. |
| Control arm | BCG alone | Induction + maintenance | None | The longstanding standard approach in high-risk BCG-naive NMIBC. |
| Investigational arm | Additional investigational combination | According to the study design | According to the research protocol | This arm was not the main decisive comparison for FDA approval. |
Significant Improvement in Disease-Free Survival: HR 0,68
The main efficacy endpoint for FDA approval was investigator-assessed disease-free survival. It was defined as the time to the first recurrence of high-risk NMIBC, persistent CIS, muscle-invasive bladder cancer, metastatic disease or death.
Durvalumab + BCG induction and maintenance significantly improved disease-free survival compared with BCG induction and maintenance alone: HR 0,68; 95% confidence interval 0,50-0,93; two-sided P value 0,0154. Median disease-free survival had not yet been reached in either arm.
The Clinical Meaning of This Result
- Relative risk reduction: Durvalumab + BCG reduced the risk of high-risk disease recurrence or a DFS event by approximately 32%.
- Median DFS was not reached: This shows that both arms included patients who remained event-free for a long time, but because there is no median value, the difference should be interpreted through the HR.
- Maintenance BCG is critical: Earlier POTOMAC data suggest that BCG induction alone is insufficient and that the combination's significant effect emerges with the BCG induction + maintenance backbone.
- Practical message: This approval is a strategy to strengthen BCG's immune effect with modern PD-L1 blockade, not to reduce BCG.
Adverse Effects and Monitoring Note
Durvalumab is a systemic immune checkpoint inhibitor. Immune-related adverse effects must therefore be considered in addition to intravesical BCG. The FDA prescribing information includes warnings for immune-mediated adverse events, infusion-related reactions, complications of allogeneic hematopoietic stem cell transplantation and embryo-fetal toxicity.
In clinical practice, this treatment should be delivered with awareness of immune-related adverse effect management not only in urology, but also in uro-oncology, medical oncology and, when needed, specialties such as endocrinology, gastroenterology, dermatology and pulmonology.
BCG Maintenance Once Changed the Standard; Modern Immunotherapy Is Now Being Added to BCG
The effect of BCG in high-risk NMIBC has been known for many years. Maintenance BCG added to induction has played a particularly important role in reducing recurrences. Historical studies such as SWOG 8507 showed that BCG maintenance improved recurrence control compared with induction alone. Considering BCG together with a maintenance program, rather than only short-term induction, therefore became a fundamental part of treatment in high-risk patients.
POTOMAC takes this historical trajectory a step further. Previously, the question was “Should we add maintenance to BCG induction?” Today, it has become “Should we add a modern immune checkpoint inhibitor to the BCG induction + maintenance backbone?”
| Period / strategy | Patient context | Main approach | Key result | Clinical meaning |
|---|---|---|---|---|
| TURBT alone | Removal of the visible tumor | Endoscopic resection | Recurrence risk remains high | Insufficient on its own in a high-risk patient. |
| BCG induction | High-risk NMIBC | Weekly intravesical BCG administrations | Local immune response reduces recurrence risk | The historical foundation of immunotherapy in NMIBC. |
| BCG induction + maintenance | High-risk NMIBC | Repeated maintenance administrations after induction | Maintenance BCG has historically strengthened recurrence control | Formed the longstanding standard treatment backbone. |
| Durvalumab + BCG | BCG-naive high-risk NMIBC | BCG induction/maintenance + 1 year of PD-L1 blockade | 32% reduction in DFS event risk; HR 0,68 | A newly approved approach that strengthens BCG with modern systemic immunotherapy. |
Compare Carefully: Durvalumab + BCG in the First Line, Most Others after BCG Failure
To understand this approval's true importance, durvalumab + BCG should be considered alongside not only BCG alone, but also other FDA-approved bladder-preserving treatments in high-risk NMIBC. However, there is a critical methodological warning: these treatments were not tested in the same treatment setting.
Durvalumab + BCG is approved for BCG-naive high-risk NMIBC and is therefore used at the start of BCG treatment. Nadofaragene firadenovec, nogapendekin alfa inbakicept + BCG, the gemcitabine intravesical system and valrubicin are generally used in BCG-unresponsive disease, meaning patients whose disease persists or recurs after adequate BCG. Pembrolizumab is also FDA-approved in this setting, but is a systemic intravenous treatment rather than an intravesical one.
Truecheck Note
The table below is not a direct head-to-head comparison of efficacy. Study designs, patient populations, treatment settings and endpoints differ. Nevertheless, viewing FDA-approved bladder-preserving options together within the same disease area is valuable for understanding the clinical decision tree.
| Treatment | Route of administration | FDA approval setting | Key trial / evidence | Main efficacy result | Clinical interpretation |
|---|---|---|---|---|---|
| Durvalumab + BCG | IV durvalumab + intravesical BCG | BCG-naive high-risk NMIBC | POTOMAC phase 3, randomized; 1.018 patients | HR 0,68 for DFS; P=0,0154; median DFS not reached in either arm | A new approval supported by randomized phase 3 data that strengthens the first-line BCG standard. |
| BCG induction + maintenance | Intravesical | Standard backbone in high-risk NMIBC | Historical randomized studies and long-term clinical experience | Reduces recurrence risk, but some patients develop recurrence/progression | The durvalumab approval does not replace this backbone; it strengthens it with immunotherapy. |
| Nadofaragene firadenovec-vncg (Adstiladrin) | Intravesical gene therapy | BCG-unresponsive high-risk NMIBC, CIS ± papillary tumor | CS-003 single-arm study | CR 51%; median response duration 9,7 months; 46% of responders maintained CR for at least 1 year | An intravesical gene therapy option for patients seeking bladder preservation after BCG. |
| Nogapendekin alfa inbakicept-pmln + BCG (Anktiva + BCG) | Intravesical immunotherapy + BCG | BCG-unresponsive NMIBC, CIS ± Ta/T1 papillary disease | QUILT-3.032 single-arm study; 77 patients | CR 62%; response lasted ≥12 months in 58% and ≥24 months in 40% of patients achieving CR | An option after BCG failure that strengthens the immune response through the IL-15 axis together with BCG. |
| Gemcitabine intravesical system (Inlexzo / TAR-200) | Intravesical drug delivery system | BCG-unresponsive NMIBC, CIS ± papillary tumor | SunRISe-1 Cohort 2; single-arm study; 83 patients | CR 82%; response lasted ≥12 months in 51% of patients achieving CR | A new bladder-preserving approach showing a very strong CR rate through continuous intravesical gemcitabine delivery. |
| Valrubicin | Intravesical chemotherapy | BCG-refractory / post-BCG-failure CIS; patients unable or unwilling to undergo cystectomy | Historical single-arm studies | Low CR rates; historical results reported approximately 21% at 6 months and 8% at 1 year | An older FDA-approved option, now rarely preferred because of limited long-term efficacy. |
| Pembrolizumab | Systemic intravenous immunotherapy | BCG-unresponsive high-risk NMIBC, CIS ± papillary tumor; patients unable or unwilling to undergo cystectomy | KEYNOTE-057 single-arm phase 2 | CR 41%; median response duration 16,2 months; 46% of responders maintained a response for at least 12 months | Not intravesical, but an important FDA-approved systemic bladder-preserving option in BCG-unresponsive NMIBC. |
What Does This Table Tell Us?
Durvalumab + BCG differs by targeting the high-risk period when BCG is first used, rather than the period after BCG failure. This is very important for the treatment paradigm. Many other bladder-preserving treatments come into play after the patient becomes unresponsive to BCG. Durvalumab + BCG, by contrast, aims to reduce recurrence risk from the outset and protect the patient before entering the BCG-unresponsive stage.
The clinical value of this new approval should therefore not be interpreted merely as “another drug has been added to BCG.” The main message is: Treatment of high-risk NMIBC is shifting from salvage treatment after failure toward proactive combination strategies that strengthen the immune response from the outset.
How Should We Discuss This with the Patient?
“Although your disease has not invaded the bladder muscle, it carries a risk of recurrence or progression because it is high-risk. Our standard treatment is BCG administered into the bladder. The new FDA approval shows that adding an immunotherapy called durvalumab to BCG may reduce recurrence or progression risk in some high-risk patients. However, this treatment can carry systemic immunotherapy adverse effects, so we should assess the benefits and risks together.”
Automatically for Every High-Risk Patient? No, but a Strong Option in Very High-Risk Patients
Although durvalumab + BCG approval covers a broad patient group, selection will be critical in practice. Combination treatment means more intense immune activation than BCG alone. This may provide better disease control, but also requires careful monitoring of immune-related adverse effects.
This approach will be discussed more extensively particularly in patients with very high-risk T1 high-grade tumors, CIS, multifocality, a large tumor burden, biology suggesting a high risk of early recurrence, or a potential substantial loss of quality of life if cystectomy becomes necessary. Conversely, greater caution is needed in patients with autoimmune disease, severe immunosuppression, uncontrolled comorbidities or a high risk of immunotherapy adverse effects.
Practical Patient Selection Questions
- What is the risk level? The value of additional treatment may increase with T1 high-grade disease, CIS, multifocality and a large tumor burden.
- Can maintenance BCG be delivered? The POTOMAC message suggests that BCG maintenance is important for the combination's effect.
- What is the risk of immunotherapy adverse effects? Autoimmune disease, organ transplantation and serious lung/liver/endocrine risks should be assessed.
- How does the patient view cystectomy? The wish to preserve the bladder must be balanced against oncological safety in high-risk NMIBC.
- Is disciplined follow-up feasible? Patient adherence is critical for cystoscopy, cytology, any necessary biopsy and monitoring immune-related adverse effects.
Radical Cystectomy Is Still on the Agenda
Although new bladder-preserving treatments are very valuable, early radical cystectomy may still be the safest oncological option for some high-risk NMIBC patients. Cystectomy should not be delayed, particularly if very high-risk biology, repeated high-grade recurrence, an inadequate response in T1 high-grade disease or BCG-unresponsive disease develops.
Strengthening the Immune Response at the First Treatment Rather than Waiting for BCG Failure
Academic Assessment
Durvalumab + BCG approval marks an important threshold in high-risk non-muscle-invasive bladder cancer. Until now, many new treatments entered the picture after BCG failure, when the disease had become more resistant and higher-risk. POTOMAC offers a different strategy: strengthening the local immune response with systemic PD-L1 blockade when BCG is first administered.
This approach makes particular sense in high-risk patients because the aim is not only to treat the visible tumor, but also to reduce early recurrence, persistent CIS, muscle invasion and ultimately progression toward cystectomy. The 32% reduction in DFS event risk is clinically meaningful in this respect.
However, this approval should not be read as “durvalumab should be added for every BCG-naive NMIBC patient.” The most appropriate approach is an explicit discussion of the benefit-risk balance in high-risk patients who can receive maintenance BCG, are suitable with regard to immunotherapy adverse effects and can be followed closely.
A New Era in High-Risk NMIBC: From Salvage Treatment to Proactive Combination
The FDA's approval of durvalumab + BCG on 28 May 2026 has the potential to change the standard significantly in high-risk BCG-naive non-muscle-invasive bladder cancer. POTOMAC showed that adding durvalumab to BCG induction and maintenance significantly improved disease-free survival compared with BCG alone. HR 0,68 and a 32% relative risk reduction represent a clinically notable gain in this patient group.
The key distinction from other FDA-approved intravesical NMIBC treatments is the treatment setting. Treatments such as nadofaragene firadenovec, Anktiva + BCG, Inlexzo/TAR-200 and valrubicin are generally used in the BCG-unresponsive period, after BCG failure. Durvalumab + BCG comes into play during the high-risk period when BCG is first used and aims to protect the patient before BCG failure.
The new approval's main message is therefore this: NMIBC treatment is no longer solely the domain of local agents administered into the bladder; it is entering a new immuno-oncological era combining local intravesical immunotherapy with systemic immune checkpoint blockade. Patient selection, immune-related adverse effect management, cost-effectiveness, BCG access and cystectomy timing will determine this new standard's place in real-world practice.
Sources
- U.S. FDA. FDA approves durvalumab in combination with Bacillus Calmette-Guerin for high-risk non-muscle invasive bladder cancer. 28 May 2026.
- drozdogan.com. Adding Durvalumab to BCG Prevents Recurrence in High-Risk Bladder Cancer. 24 January 2026.
- De Santis M, Palou Redorta J, Nishiyama H et al. Durvalumab in combination with BCG for BCG-naive, high-risk, non-muscle-invasive bladder cancer (POTOMAC): final analysis of a randomised, open-label, phase 3 trial. The Lancet. 2025;406:2221-2234.
- ClinicalTrials.gov. POTOMAC study: Durvalumab + BCG in non-muscle-invasive bladder cancer. NCT03528694.
- U.S. FDA. FDA approval of Adstiladrin (nadofaragene firadenovec-vncg) for high-risk BCG-unresponsive NMIBC with CIS with or without papillary tumors. 16 December 2022.
- U.S. FDA. FDA approves nogapendekin alfa inbakicept-pmln with BCG for BCG-unresponsive NMIBC. 22 April 2024.
- U.S. FDA. FDA approves gemcitabine intravesical system (Inlexzo/TAR-200) for BCG-unresponsive NMIBC. 9 September 2025.
- KEYNOTE-057. Pembrolizumab monotherapy in BCG-unresponsive high-risk NMIBC with CIS with or without papillary tumors.
- Urology Times. Management of BCG-unresponsive NMIBC: valrubicin and other FDA-approved options.
- Cancer Network. Efficacy of BCG maintenance in bladder cancer is confirmed: SWOG 8507 historical data.
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