Required efficacy for novel therapies in BCG-unresponsive non-muscle invasive bladder cancer: Do current recommendations really reflect clinically meaningful outcomes?

A Review on Calibration Methods of Cancer Simulation Models

Calibration, a critical step in the development of simulation models, involves adjusting unobservable parameters to ensure that the outcomes of the model closely align with observed target data. This process is particularly vital in cancer simulation models with a natural history component where direct data to inform natural history parameters are rarely available. This work reviews the literature of cancer simulation models with a natural history component and identifies the calibration approaches used in these models with respect to the following attributes: calibration target, goodness-of-fit (GOF) measure, parameter search algorithm, acceptance criteria, and stopping rules. After a comprehensive search of the PubMed database from 1981 to June 2023, 68 studies were included in the review. Nearly all (n=66) articles specified the calibration targets, and most articles (n=56) specified the parameter search algorithms they used, whereas goodness-of-fit metric (n=51) and acceptance criteria/stopping rule (n=45) were reported for fewer times. The most frequently used calibration targets were incidence, mortality, and prevalence, whose data sources primarily come from cancer registries and observational studies. The most used goodness-of-fit measure was weighted mean squared error. Random search has been the predominant method for parameter search, followed by grid search and Nelder-mead method. Machine learning-based algorithms, despite their fast advancement in the recent decade, has been underutilized in the cancer simulation models. More research is needed to compare different parameter search algorithms used for calibration.

Key points

This work reviewed the literature of cancer simulation models with a natural history component and identified the calibration approaches used in these models with respect to the following attributes: calibration target, goodness-of-fit (GOF) measure, parameter search algorithm, acceptance criteria, and stopping rules.Random search has been the predominant method for parameter search, followed by grid search and Nelder-mead method.Machine learning-based algorithms, despite their fast advancement in the recent decade, has been underutilized in the cancer simulation models. Furthermore, more research is needed to compare different parameter search algorithms used for calibration.

The UF-5000 Atyp.C parameter is an independent risk factor for bladder cancer

Bladder carcinoma (BC) accounts for > 90% of all urothelial cancers. Pathological diagnosis through cytoscopic biopsy is the gold standard, whereas non-invasive diagnostic tools remain lacking. The "Atyp.C" parameter of the Sysmex UF-5000 urine particle analyzer represents the ratio of nucleus to cytoplasm and can be employed to detect urinary atypical cells. The present study examined the association between urinary Atyp.C values and BC risk. This two-center, retrospective case-control study identified clinical primary or newly recurrent BC (study period, 2022-2023; n = 473) cases together with controls with urinary tract infection randomly matched by age and sex (1:1). Urinary sediment differences were compared using non-parametric tests. The correlations between urinary Atyp.C levels and BC grade or infiltration were analyzed using Spearman's rank correlation. The BC risk factor odds ratio of Atyp.C was calculated using conditional logistic regression, and potential confounder effects were adjusted using stepwise logistic regression (LR). Primary risk factors were identified by stratified analysis according to pathological histological diagnosis. The mean value of urinary Atyp.C in BC cases (1.30 ± 3.12) was 8.7 times higher than that in the controls (0.15 ± 0.68; P < 0.001). Urinary Atyp.C values were positively correlated with BC pathological grade and invasion (r = 0.360, P < 0.001; r = 0.367, P < 0.001). Urinary Atyp.C was an independent risk factor for BC and closely related with BC pathological grade and invasion. Elevated urinary Atyp.C values was an independent risk factor for BC. Our findings support the use of Atyp.C as a marker that will potentially aid in the early diagnosis and long-term surveillance of new and recurrent BC cases.

Hyperthermic Intravesical Chemotherapy (HIVEC) Using Epirubicin in an Optimized Setting in Patients with NMIBC Recurrence after Failed BCG Therapy

To evaluate hyperthermic intravesical chemotherapy (HIVEC) using conductive heating and epirubicin in an optimized setting as an alternative to radical cystectomy in patients with recurrent non-muscle invasive bladder cancer (NMIBC) who have failed bacillus Calmette-Guérin (BCG) therapy. We retrospectively analyzed our prospectively recorded database of patients who underwent HIVEC between 11/2017 and 11/2022 at two Swiss University Centers. Cox regression analysis was used for univariate/multivariate analysis, and the Kaplan-Meier method for survival analysis. Of the 39 patients with NMIBC recurrence after failed BCG therapy, 25 (64%) did not recur within the bladder after a median follow-up of 28 months. The 12- and 24-month intravesical RFS were 94.8% and 80%, respectively. Extravesical recurrence developed in 14/39 (36%) of patients. Only 7/39 (18%) patients had to undergo radical cystectomy. Seven patients (18%) progressed to metastatic disease, with five of these (71%) having previously developed extravesical disease. No adverse events > grade 2 occurred during HIVEC. Device-assisted HIVEC using epirubicin in an optimized setting achieved excellent RFS rates in this recurrent NMIBC population at highest risk for recurrence after previously failed intravesical BCG therapy. Extravesical disease during or after HIVEC, however, was frequent and associated with metastatic disease and consecutively poor outcomes.

Patterns of treatment of high-risk BCG-unresponsive non-muscle invasive bladder cancer (NMIBC) patients among Arab urologists

PURPOSE

To understand the treatment plans suggested for BCG-unresponsive non-muscle invasive disease (NMIBC) patients in the Arab countries and therapeutic decisions applied for BCG-naive patients during BCG shortage time.

METHODS

A 10-minute online survey was distributed through the Arab Association of Urology (AAU) office to urologists in the Arab countries who treat patients with NMIBC.

RESULTS

One hundred six urologists responded to the survey. The majority of urologists had treated, in the past 6 months, > 10 patients with NMIBC who were considered BCG-unresponsive (55% of respondents). Radical cystectomy (RC) was the most popular treatment option (recommended by 50%) for these patients. This was followed by intravesical chemotherapy (30%), repeat BCG therapy (12%), resection with ongoing surveillance (8%). Clinical trials and intravenous checkpoint inhibitors were never selected. The most preferred intravesical chemotherapy was by ranking: 60% gemcitabine, 19% mitomycin C, 8% docetaxel, 8% gemcitabine/docetaxel, 4% sequential gemcitabine/mitomycin C, and 1% valrubicin. The use of intravesical chemotherapy appears limited by Arab urologists due to concerns regarding clinical efficacy (fear of progression) and the lack of clear recommendations by urology societies. Given the BCG shortage, which may vary per Arab country, Arab urologists have adjusted by prioritizing BCG for T1 and carcinoma in situ (CIS) patients over Ta, adapting intravesical chemotherapy, and reducing the dose/strength of BCG administered. Most physicians report an eagerness to utilize novel therapies to address the BCG deficit, especially to try intravesical chemotherapy.

CONCLUSIONS

Even though Arab urologists are in the majority of cases selecting RC for BCG-unresponsive cases, one-third of them are most recently initiating intravesical chemotherapy as an alternative option. To further assist Arab urologists in the appropriate selection of BCG unresponsive high risk NMIBC patient treatments, enhanced education and pathway protocols are needed.

Quality of Life and Anxiety in Patients with First Diagnosed Non-Muscle Invasive Bladder Cancer Who Receive Adjuvant Bladder Therapy

BACKGROUND

Bladder cancer (BC) is one of the most common malignancies (4.5%of all newly diagnosed cases worldwide). Most of the new BC cases are diagnosed as non-muscle invasive BC (NMIBC), needing continuous follow up after primary endoscopic therapy. Adjuvant bladder therapy with chemo- or immuno- agents, apart from the initial diagnosis, the strict surveillance program and the risk of recurrence, may have a major impact on the patients' physical and mental health.

OBJECTIVE

We evaluated anxiety and quality of life (QoL) in patients who underwent surgery for NMIBC and followed a bladder instillation programme.

METHODS

This is a prospective analysis of patients with histopathologically confirmed NMIBCs. Eligible were all adult patients with a single or multiple NMIBCs who underwent a transurethral tumor resection and followed a therapy with either BCG or Epirubicin instillations. The SF-36 questionnaire Physical and Mental health aspects were used for QoL assessment. Similarly, the STAI-Y was introduced for the state (STAI-Y1) and trait anxiety (STAI-Y2) evaluation.

RESULTS

117 eligible patients were screened, with 108 entering finally the study; 9 patients were excluded due to disease recurrence. 17 patients (15.7%) received Epirubicin (Ta-T1, Low Grade tumors), whereas 91 patients (84.3%) received BCG (T1, High Grade). Regarding SF-36 Physical a 6 months decrease was followed by an improvement at 12 months (p = 0.008). Similarly, an increase of the SF-36 Mental health score was identified (p = 0.03). In contrast to STAI-Y2 scores (p = 0.945), a long-term reduction of the state anxiety was identified (p = 0.001). Preoperative SF-36 Physical was inversely correlated with age (p = 0.029), while absence of alcohol was associated with lower mental health (p = 0.003). Overall, patient characteristics, habits and the administered treatment did not affect the postoperative QoL and anxiety.

CONCLUSION

Patient QoL and anxiety improved during follow up. Still, further larger scale studies are required to support our findings.

Secondary metabolites from Bacillus sp. MERNA97 extract attenuates the oxidative stress, genotoxicity and cytotoxicity of aflatoxin B1 in rats

This study aimed to determine the bioactive compounds of Bacillus sp. MERNA97 extract and to evaluate their efficacy against the oxidative damage, genotoxicity, chromosomal aberration and DNA fragmentation in rats treated with AFB₁. Sixty male Sprague-Dawley rats were divided into 6 groups and treated for 6 weeks and included the control group, AFB₁-treated group (80 μg/kg b. w), the groups treated with Bacillus extract (BE) at low (2 mg/kg b.w) or high (4 mg/kg b.w) dose and the groups treated with AFB₁ plus BE at the two doses. Blood and tissues samples were collected for different assays. The GC-MS results revealed the isolation of 44 compounds belong to different classes. The in vivo results showed that AFB₁ disturbs all the biochemical parameters, oxidative stress markers, cytokines gene expression chromosomal aberration and DNA fragmentation along with the histological changes in the liver tissue. BE at the two tested doses induced a significant improvement in all parameters tested and the histological picture in a dose dependent manner. It could be concluded that the extract of Bacillus sp. MERNA97 isolated from the marine environment in the Red Sea is a promise as a source of novel compounds with therapeutically benefits.

Required efficacy for novel therapies in BCG-unresponsive non-muscle invasive bladder cancer: Do current recommendations really reflect clinically meaningful outcomes?

Background

Single‐arm trials are currently an accepted study design to investigate the efficacy of novel therapies (NT) in non‐muscle invasive bladder cancer (NMIBC) unresponsive to intravesical Bacillus Calmette‐Guérin (BCG) immunotherapy as randomized controlled trials are either unfeasible (comparator: early radical cystectomy; ERC), or unethical (comparator: placebo). To guide the design of such single‐arm trials, expert groups published recommendations for clinically meaningful outcomes. The aim of this study was to quantitatively verify the appropriateness of these recommendations.

Methods

We used a discrete event simulation framework in combination with a supercomputer to find the required efficacy at which a NT can compete with ERC when it comes to quality‐adjusted life expectancy (QALE). In total, 24 different efficacy thresholds (including the recommendations) were investigated.

Results

After ascertaining face validity with content experts, repeated verification, external validation, and calibration we considered our model valid. Both recommendations rarely showed an incremental benefit of the NT over ERC. In the most optimistic scenario, an increase in the IBCG recommendation by 10% and an increase in the FDA/AUA recommendation by 5% would yield results at which a NT could compete with ERC from a QALE perspective.

Conclusions

This simulation study demonstrated that the current recommendations regarding clinically meaningful outcomes for single‐arm trials evaluating the efficacy of NT in BCG‐unresponsive NMIBC may be too low. Based on our quantitative approach, we propose increasing these thresholds to at least 45%‐55% at 6 months and 35% at 18‐24 months (complete response rates/recurrence‐free survival) to promote the development of clinically truly meaningful NT.