Oral bropirimine immunotherapy of bladder carcinoma in situ after prior intravesical bacille Calmette-Guérin

BCG-Unresponsive Non-Muscle-Invasive Bladder Cancer: Current Treatment Landscape and Novel Emerging Molecular Targets

Urothelial carcinoma (UC), the sixth most common cancer in Western countries, includes upper tract urothelial carcinoma (UTUC) and bladder carcinoma (BC) as the most common cancers among UCs (90-95%). BC is the most common cancer and can be a highly heterogeneous disease, including both non-muscle-invasive (NMIBC) and muscle-invasive (MIBC) forms with different oncologic outcomes. Approximately 80% of new BC diagnoses are classified as NMIBC after the initial transurethral resection of the bladder tumor (TURBt). In this setting, intravesical instillation of Bacillus Calmette-Guerin (BCG) is the current standard treatment for intermediate- and high-risk patients. Unfortunately, recurrence occurs in 30% to 40% of patients despite adequate BCG treatment. Radical cystectomy (RC) is currently considered the standard treatment for NMIBC that does not respond to BCG. However, RC is a complex surgical procedure with a recognized high perioperative morbidity that is dependent on the patient, disease behaviors, and surgical factors and is associated with a significant impact on quality of life. Therefore, there is an unmet clinical need for alternative bladder-preserving treatments for patients who desire a bladder-sparing approach or are too frail for major surgery. In this review, we aim to present the strategies in BCG-unresponsive NMIBC, focusing on novel molecular therapeutic targets.

Systematic Review of the Therapeutic Efficacy of Bladder-preserving Treatments for Non-muscle-invasive Bladder Cancer Following Intravesical Bacillus Calmette-Guérin

CONTEXT

There is a critical need for effective bladder-sparing therapies for bacillus Calmette-Guérin (BCG)-unresponsive non-muscle-invasive bladder cancer (NMIBC). Owing to the current lack of effective agents that can be used as a control, the US Food and Drug Administration began to accept single-arm trials for patients with carcinoma in situ (CIS), using complete response rate (CRR) and duration of response as the primary endpoints to support marketing applications. Despite the ensuing growth of clinical trials in this space, no consensus exists on a clinically relevant benchmark for CRR.

OBJECTIVE

To elucidate the CRR and recurrence-free rate (RFR) using bladder-sparing agents after BCG failure in order to provide a frame of reference for future clinical trial results.

EVIDENCE ACQUISITION

We performed a systematic review of clinical trials utilizing bladder-sparing therapeutics for NMIBC recurring after intravesical BCG (PROSPERO CRD42019130553). The search was performed in MEDLINE, EMBASE, and Cochrane Library. Relevant studies identified from bibliography search and conference abstracts were searched to complement the systematic review. A total of 42 studies utilizing 24 treatment options and consisting of 2254 patients were included for final analysis.

EVIDENCE SYNTHESIS

Median CRRs in the treatment of CIS-containing tumors were 26% at 6 mo, 17% at 12 mo, and 8% at 24 mo after treatment. In comparison, median RFRs in the papillary-only studies were 67% at 6 mo, 44% at 12 mo, and 10% at 24 mo. Specifically in the BCG-unresponsive population, 6- and 12-mo CRRs in CIS-containing patients treated with Mycobacterium phlei cell wall-nucleic acid complex were 45% and 27%, respectively, and the median 6-, 12-, and 24-mo disease-free rates in the other studies were 43%, 35%, and 18%, respectively. The median progression-free rate was 91%: 95% in the CIS-containing studies and 89% in studies restricted to papillary-only recurrences. Toxicities of intravesical agents were generally mild, with very few dose limiting toxicities.

CONCLUSIONS

We demonstrate that, to date, bladder-sparing therapies achieved modest efficacy in patients with NMIBC after BCG. Results from the current study will serve as a frame of reference for emerging trial results in the BCG-unresponsive space.

PATIENT SUMMARY

In this study, we found that bladder-sparing therapies achieved modest efficacy in patients with non-muscle-invasive bladder cancer after bacillus Calmette-Guérin (BCG). These results will serve to inform future clinical trial results for salvage agents used to treat BCG-unresponsive bladder cancer.

Bacillus Calmette-Guérin (BCG) Treatment Failures with Non-Muscle Invasive Bladder Cancer: A Data-Driven Definition for BCG Unresponsive Disease

Objective: To create the first data-driven definition for those unlikely to benefit from further BCG treatment.

Materials and Methods: The database created for the Phase 2 BCG-Interferon-α 2B (IFN) study was queried and BCG failure patients were identified (n = 334). Full study protocols have previously been published. Separate models were constructed for analysis of patients with any CIS (pure or concomitant) and pure papillary disease. Variables considered included age, gender, stage, grade, tumor size and focality (for papillary only), number of prior BCG courses, and prior BCG failure interval.

Results: Patients with recurrent CIS within 6 months of their most recent prior BCG course (HR 2.56, p <  0.01) and ≥2 prior BCG failures (HR 1.54, p <  0.01) responded worst to repeat intravesical therapy. Those with CIS recurrence at 6–12 months did not differ from those recurring within 6 months (HR = 0.88, p = 0.71). Patients with recurrent papillary disease within 6 months (HR 1.82, p = 0.02), ≥2 BCG failures (HR 1.54, p = 0.03), and multifocal disease (HR 2.05, p <  0.01) responded worst to therapy. Patients with T1 disease remained disease free in 38% of cases (24–51% 95% CI) at 2 years with low rates of progression.

Conclusions: Patients who fail two courses of BCG with either persistent or recurrent multifocal papillary disease within 6 months or CIS within 12 months of their prior BCG should be considered BCG unresponsive. Recurrent T1 disease respond reasonably well to another course with low progression rates but further investigation is warranted.

Bacillus Calmette-Guérin (BCG) Treatment Failures in Non-Muscle Invasive Bladder Cancer: What Truly Constitutes Unresponsive Disease

Bacillus Calmette-Guérin (BCG) remains the most effective intravesical therapy for non-muscle invasive bladder cancer but will fail in up to 40% of patients. The ability to identify patients who are least likely to respond to further BCG therapy allows urologists to pursue secondary treatments more likely to convey a recurrence or survival benefit to the patient. We examined the literature to determine what constitutes BCG unresponsive disease. After review, we believe that BCG unresponsive disease should be defined as (1) patients with recurrent high grade T1 disease within 6 months of their primary tumor after at least one course of BCG or patients who have failed at least 2 courses of BCG with either (2) persistent or recurrent pure papillary (Ta) disease within 6 months or (3) persistent or recurrent carcinoma in situ (CIS) within 12 months.

Investigational therapies for non-muscle invasive bladder cancer

IMPORTANCE OF THE FIELD

Bacillus Calmette-Guérin (BCG) is currently the most effective adjuvant intravesical agent at preventing disease recurrence and the only therapy shown to inhibit disease progression in non-muscle invasive bladder cancer (NMIBC). However, recurrence rates as high as 30% and significant local/systemic toxicity have resulted in an increased interest in the use of alternative intravesical agents.

AREAS COVERED IN THE REVIEW

Our aim is to discuss recent clinical trial evidence utilizing novel intravesical agents for treatment of NMIBC. A systematic literature review was performed via the National Center for Biotechnology Information databases to identify pertinent studies from 2000-2009.

WHAT THE READER WILL GAIN

A durable response has been demonstrated with alternative agents in patients refractory to or intolerant of BCG. This review compares the merits and shortcomings of these emerging agents, focusing on clinical trial safety and efficacy results.

TAKE HOME MESSAGE

Despite recent enthusiasm for novel agents, radical cystectomy remains the treatment of choice for patients with NMIBC who have failed intravesical therapy. However, evidence is accumulating that novel agents provide an efficacious alternative in patients refractory or intolerable to BCG or unfit for cystectomy. Further randomized prospective data are required to demonstrate a recurrence- and progression-free benefit compared with BCG.

Definition and management of patients with bladder cancer who fail BCG therapy

Intravesical administration of bacillus Calmette-Guérin (BCG) following resection of non-muscle-invasive bladder tumor is the current 'gold standard'. However, up to 40% of patients will fail therapy within the first year and response rates to salvage intravesical therapy after appropriate trial of BCG (i.e., after induction and one maintenance course) average 15-20% at 1 year. Radical cystectomy remains the only treatment with proven long-term benefit after BCG failure. Nonetheless, with appropriate selection, certain patients who 'fail' BCG (but have other favorable risk factors, e.g., a long interval between BCG and recurrence) can be managed with intravesical regimens including repeated BCG, BCG plus cytokines and/or intravesical chemotherapy. In this review, optimal risk stratification, appropriate definitions and management of BCG failures are discussed.

Intravesical hyperthermia and mitomycin-C for carcinoma in situ of the urinary bladder: experience of the European Synergo working party

Objectives

To study the results of chemotherapy combined with intravesical hyperthermia in patients with mainly BCG-failing carcinoma in situ (CIS).

Methods

Patients with histologically confirmed CIS were included retrospectively. Outpatient thermochemotherapy treatment was done with mitomycin-C (MMC) and the Synergo^® system SB-TS 101 (temperature range between 41 and 44°C), weekly for 6–8 weeks, followed by 4–6 sessions every 6–8 weeks.

Results

Fifty-one patients were treated between 1997 and 2005 from 15 European centers. Thirty-four were pre-treated with BCG. Mean age was 69.9 years. Twenty-four patients had concomitant papillary tumors. The mean number of hyperthermia/MMC treatments per patient was 10.0. Of the 49 evaluable patients 45 had a biopsy and cytology proven complete response. In two patients CIS disappeared, but they had persistent papillary tumors. Follow-up of 45 complete responders showed 22 recurrences after a mean of 27 months (median 22): T2 (4), T1 (4), T1/CIS (1), CIS (5), Ta/CIS (2), Ta (5) and Tx (1). Side effects (bladder complaints) were generally mild and transient.

Conclusions

In patients with primary or BCG-failing CIS, treatment with intravesical hyperthermia and MMC appears a safe and effective treatment. The initial complete response rate is 92%, which remains approximately 50% after 2 years.

Phase II trial of intravesical gemcitabine in bacille Calmette-Guérin-refractory transitional cell carcinoma of the bladder

PURPOSE

The aim of this phase II study was to determine the efficacy of gemcitabine administered as an intravesical agent in patients with bacille Calmette-Guérin (BCG) -refractory transitional cell carcinoma of the bladder.

PATIENTS AND METHODS

Patients with superficial bladder cancer refractory or intolerant to intravesical BCG therapy and refusing a cystectomy were considered eligible for the trial. Eligible patients received two courses of intravesical gemcitabine twice weekly at a dose of 2,000 mg/100 mL for 3 consecutive weeks, with each course separated by 1 week of rest. Patients were evaluated for response at 8 weeks, then every 3 months to 1 year.

RESULTS

Thirty eligible patients were included on study. The median follow-up for all the patients was 19 months (range, 0 to 35 months). Of the 30 patients, 15 (50%; 95% CI, 32% to 68%) achieved a complete response (CR). Twelve patients had tumor recurrence with a median recurrence-free survival time of 3.6 months (95% CI, 2.9 to 11.0 months). Two patients maintained a CR at 23 and 29 months, respectively. The 1-year recurrence-free survival rate for patients with a CR was 21% (95% CI, 0% to 43%). Two patients progressed to a higher stage while receiving gemcitabine treatment. The median follow-up for patients who did not have a progression or a cystectomy was 19 months (range, 2 to 35 months). Eleven patients (37%) underwent a cystectomy subsequent to gemcitabine therapy.

CONCLUSION

Gemcitabine has activity in a high-risk patient population and remains a viable option for some patients who refuse cystectomy.

Management of BCG Failures in Superficial Bladder Cancer: A Review

OBJECTIVE

Review management of bacillus Calmette-Guérin (BCG) failures in superficial bladder cancer.

METHOD

Search of published literature and meeting abstracts.

RESULTS

Patients in whom BCG fails are not a uniform group. Failure cannot be predicted but high-risk patients can be identified. In case of failure and progression the outcome is bad. Conservative but investigative alternatives are BCG/interferon-alpha, intravesical hyperthermia/chemotherapy, or photodynamic therapy. Standard treatment in failing patients remains cystoprostatectomy.

CONCLUSION

BCG failures need careful and individualized therapy in experienced hands.

High-grade Ta urothelial carcinoma and carcinoma in situ of the bladder

We sought to review the definition, diagnosis, prognosis, and treatment of high-grade Ta urothelioma carcinoma and carcinomas in situ (CIS) in order to provide evidence-based guidelines for their diagnosis and treatment. The English-language literature on high-grade Ta urothelial carcinoma and CIS was identified and critically reviewed by a panel of 9 international experts. The panel then met at a consensus conference to present their conclusions. Levels of evidence and grades of recommendation were assessed. Findings from approximately 100 publications appearing prior to February 2005 were reviewed and summarized. High-grade Ta urothelial carcinoma and CIS are relatively rare tumors; thus results are often based on small nonrandomized studies. Their assessment is made more difficult owing to inaccuracies in staging and grading. Although there were similar numbers of level 1, level 2, and level 3 evidence citations, guidelines have been developed based only on levels of evidence supporting grade A and grade B recommendations. These evidence-based guidelines have been developed to aid clinicians in the diagnosis and treatment of patients with high-grade Ta urothelial carcinoma and CIS.

Management of stage T1 tumors of the bladder: International Consensus Panel

The International Consensus Panel on T1 bladder tumors markers reviewed the subject from a clinical perspective. From diagnosis to treatment decisions, what are the important issues in the management of a new patient? The assessment of prognostic factors for progression requires optimal resection and documentation. The role of immediate adjuvant intravesical chemotherapy after resection remains controversial. How often should the upper tract be assessed for tumor recurrence? The decision on whether to attempt bladder conservation with intravesical therapy or to perform a cystectomy is the most difficult issue in the management of superficial bladder cancer today. Finally, what therapies exist if initial intravesical bacille Calmette-Guérin fails to eradicate the disease or prevent recurrence? The panel thoroughly explored all these subjects and has made recommendations with supporting evidence.

EAU Guidelines on the Diagnosis and Treatment of Urothelial Carcinoma in Situ

OBJECTIVES

On behalf of the European Association of Urology (EAU), guidelines for the diagnosis, therapy and follow-up of patients with urothelial carcinoma in situ (CIS) have been established.

METHOD

The recommendations in these guidelines are based on a recent comprehensive overview and meta-analysis in which two panel members have been involved (RS and AVDM). A systematic literature search was conducted using Medline, the US Physicians' Data Query (PDQ), the Cochrane Central Register of Controlled Trials, and reference lists in trial publications and review articles.

RESULTS

Recommendations are provided for the diagnosis, conservative and radical surgical treatment, and follow-up of patients with CIS. Levels of evidence are influenced by the lack of large randomized trials in the treatment of CIS.

Defining bacillus Calmette-Guerin refractory superficial bladder tumors

PURPOSE

We define bacillus Calmette-Guerin (BCG) refractory, high risk, superficial bladder cancer.

MATERIALS AND METHODS

A total of 93 patients received a 6-week induction course of BCG. They were evaluated for response after 3 and 6 months. Half of the patients received monthly maintenance BCG for 2 years and half did not. In both groups the initial responses to BCG at 3 and 6 months were correlated with subsequent tumor recurrence and progression.

RESULTS

Of the 93 cases 57% were negative for tumor at 3 months and 43% had residual tumor resected. At 6 months 80% of the patients were tumor-free and 20% had persistent or recurrent tumor. Maintenance BCG did not decrease tumor recurrence further than induction BCG. Subsequent tumor-free interval during 24 months of followup were best predicted by response to BCG after 6 months.

CONCLUSIONS

A minimum treatment and followup time of 6 months is required to identify high risk, superficial bladder tumors as truly BCG refractory.

Bladder cancer: a current update

In the UK, 10,000 new cases of bladder cancer are reported per annum. Earlier diagnosis and better care have improved survival rates, but the incidence is still rising. This article updates the current understanding of bladder cancer diagnosis and management.

Medical management of patients with refractory carcinoma in situ of the bladder

Bladder cancer is a common genitourinary malignancy and carcinoma in situ (CIS) of the bladder exists as a potentially aggressive variant of the superficial form of the disease. Treatment must reflect the unpredictable nature of this disease entity. In 1976, the use of intravesical Bacillus Calmette-Guerin (BCG) was described for the management of early stage bladder cancer. A subsequent report demonstrated efficacy in a cohort of patients with CIS of the bladder. Since this time, intravesical BCG has been recognised as the initial therapy for CIS of the bladder. Although a 6-week treatment with intravesical BCG has been established as standard therapy in patients with CIS, there has been no consensus as to the subsequent treatment for patients in the setting of failure to initial management with BCG. In addition, a number of reports have demonstrated an increased potential of adverse effects after repeated treatment with intravesical BCG. A variety of alternative immunological and chemotherapeutic agents have been developed in response to the limitations of BCG for patients with refractory CIS of the bladder. At present, valrubicin remains the only agent that is approved by the US Food and Drug Administration for the specific indication of CIS of the bladder unresponsive to intravesical BCG. Although these agents appear promising, the most efficacious therapy remains to be determined. The specific treatment protocol for refractory CIS of the bladder remains elusive. It is ultimately the combined decision of the clinician and patient to determine which course of management is most beneficial.

[Progression and prognosis of in situ carcinoma of the bladder treated with BCG]

OBJECTIVES

In situ carcinoma (isT) of the bladder is a poor prognostic tumour with a natural progressive evolution. Treatment with BCG achieves a significant improvement in survival. This paper analyses our experience in the management of isT patients with endovesical BCG.

MATERIAL AND METHODS

Between 1983 and 1997 the Urology Unit in the Móstoles Hospital saw 636 patients with transitional carcinoma of the bladder. Of these, 498 (78%) were surface tumours, and 138 (22%) were infiltrant. isT: 80 patients (13%), 14 of which were primary (17%), 37 associated to a surface tumour (46%), and 29 to infiltrant tumours (36%). All surface tumours: isT was present in 51 patients (10%) 44 of which were managed with 2 courses of BCG Connaught (81 mg), for 6 weeks each followed by vesical reassessment. Quarterly follow-up was conducted during a 2-year period. Patients not managed with BCG were treated with radical cystectomy. An analysis was made of patients without complete response to BCG, as well as actuarial analysis of disease-free survival (DFS), survival until progression (SUP) and specific survival (SS). All possible prognostic factors are analyzed: sex, focal isT (a single focus) or diffuse isT (more than one focus). Primary or secondary isT and association to G1, G2 or G3 tumours.

RESULTS

In all 44 patients managed with BCG: males 37 (84%), females 7 (16%), primary 14 (32%), focal 22 (50%), diffuse 22 (50%). Six patients died (5 because of the tumour). Mean follow-up of living patients: 3.7 years (0.5-7.5 years). After the 2 BCG courses, 36 (82%) showed complete response. Thirteen patients (30%) had no complete response during follow-up, and 11 (85%) continued to progression. In total 7 patients underwent cystectomy. Of 5 patients directly cystectomized due to persistence of isT or T1G3 tumour at monitoring after BCG, 2 (40%) had infiltrant tumour and one (20%) nodular metastasis. Three patients with persistent isT or T1G3 after BCG were not initially cystectomized: two that were treated with other endovesical therapies because of their age progressed, and the third one underwent a third BCG course and required cystectomy due to tumour persistency. 5-year DFS: 56%, being diffuse isT vs. focal isT (p = 0.0206) was an unfavourable prognostic factor. 5-year SUP: 63%, no significant prognostic factor. 5-year SS: 79%, being a female was an unfavourable prognostic factor (p = 0.0201).

CONCLUSIONS

Based on our results and the analysis of the literature we recommend treatment with 2 BCG courses of all isTs of the bladder that present some of the following factors: Diffuse cancer associated to T1G3, involvement of prostatic urethra or overexpression of p53 over 20%. In the rest of vesical tumours, one BCG course followed by a second one if lack of response to the first. After failure of both BCG courses, cystectomy must be performed in both groups.

Recent perspectives in topical therapy in superficial bladder cancer

With regard to side-effects in intravesical bacillus Calmette-Guérin instillation therapy and the limited efficacy of intravesical chemotherapy, there is still a need for improvement of these standard therapies. Recently, technical adjuvant means or the modification of cytostatic drugs have been undertaken to improve the efficacy of intravesical chemotherapy. Prognostic indicators of the response to bacillus Calmette-Guérin immunotherapy have been identified, but indicators of side-effects are needed in order to improve the benefit-to-risk ratio of bacillus Calmette-Guérin instillation therapy. Many innovative treatment options, however, still require a definition of their clinical value.