Neoadjuvant paradigm for accelerated drug development: an ideal model in bladder cancer

Neoadjuvant Cisplatin-based Chemotherapy in Nonmetastatic Muscle-invasive Bladder Cancer: A Systematic Review and Pooled Meta-analysis to Determine the Preferred Regimen

OBJECTIVE

To determine whether neoadjuvant gemcitabine and cisplatin (GC) vs dose-dense methotrexate, vinblastine, doxorubicin, and cisplatin (ddMVAC) before radical cystectomy improves overall survival (OS), progression-free survival (PFS), and pathologic complete response (pCR) for patients with muscle-invasive bladder cancer with secondary analyses of pathological downstaging and toxicity.

MATERIALS AND METHODS

This systematic review and meta-analysis identified studies of patients with muscle-invasive bladder cancer treated with neoadjuvant GC compared to ddMVAC from PubMed, Web of Science, and EMBASE. Random-effect models for pooled log-transformed hazard ratios (HR) for OS and PFS and pooled odds ratios for pCR and downstaging were developed using the generic inverse variance method and Mantel-Haenszel method, respectively.

RESULTS

Ten studies were identified (4 OS, 2 PFS, and 6 pCR clinical endpoints). Neoadjuvant ddMVAC improved OS (HR 0.71 [95% confidence intervals 0.56; 0.90]), PFS (HR 0.76 [95% confidence intervals 0.60; 0.97]), and pathological downstaging (odds ratio 1.34 [95% confidence interval 1.01; 1.78]) as compared to GC. There was no significant difference between regimens for pCR rates (odds ratio 1.38 [95% confidence interval 0.90; 2.12]). Treatment toxicity was greater with ddMVAC. Limitations result from differences in number of ddMVAC cycles and patient selection between studies.

CONCLUSION

Neoadjuvant ddMVAC is associated with improved OS and PFS vs gemcitabine/cisplatin for patients with muscle-invasive bladder cancer before radical cystectomy. Although rates of pathological complete response were not significantly different, pathological downstaging correlated with OS. ddMVAC should be preferred over gemcitabine/cisplatin for patients with muscle-invasive bladder cancer who can tolerate its greater toxicity.

The past, present, and future of pT0 in bladder cancer clinical trials

PURPOSE OF REVIEW

Since the establishment of neoadjuvant chemotherapy as the standard of care for patients with muscle invasive bladder cancer, the pathologic absence of disease, denoted pT0, was found to be predictive of improved overall survival. Accordingly, it has been used in clinical trials as an optimal surrogate outcome measure, even in contemporary nonchemotherapeutic interventions. We review the role of pT0 as a catalyst for change in trial design and its suitability to facilitate more efficient and timely results. In addition, we explore the present and future of cT0, the clinical absence of disease, in defining treatment response and enabling bladder-sparing management options.

RECENT FINDINGS

The use of pT0 as a surrogate has provided initial results for the efficacy of immunotherapy in the neoadjuvant space. In combination with molecular markers, pT0 has improved our ability to identify treatment responders and its clinical counterpart, cT0, has been integrated into multiple trials to redefine postneoadjuvant chemotherapy management algorithms.

SUMMARY

The use of pT0 as a surrogate endpoint in bladder cancer trials has improved clinical trial design, defined efficacy of emerging therapeutics, and has the potential to redefine the postneoadjuvant treatment management for patients seeking bladder-sparing options.

The long-term efficacy of one-shot neoadjuvant intra-arterial chemotherapy combined with radical cystectomy versus radical cystectomy alone for bladder cancer: a propensity-score matching study

Background

Bladder cancer is a complex disease associated with high morbidity and mortality. Management of bladder cancer before radical cystectomy continues to be controversial. We compared the long-term efficacy of one-shot neoadjuvant intra-arterial chemotherapy (IAC) versus no IAC (NIAC) before radical cystectomy (RC) for bladder cancer.

Methods

We performed a retrospective review of patients who underwent either one-shot IAC or NIAC before RC between October 2006 and November 2015. A propensity-score matching (1:3) was performed based on key characters. The Kaplan-Meier method was utilized to estimate survival probabilities, and the log-rank test was used to compare survival outcomes between different groups. A multivariable Cox proportional hazard model was used to estimate survival outcomes.

Results

Twenty-six patients were treated using IAC before RC, and 123 NIAC patients also underwent RC. After matching, there was no significant difference between groups in baseline characteristics, perioperative variables, complication outcomes or tumor characteristics. Compared with clinical tumor stages, pathological tumor stages demonstrated a significant decrease (P = 0.002) in the IAC group. There was no significant difference in overall survival (OS, p = 0.354) or cancer-specific survival (CSS, p = 0.439) between the groups. Among all patients, BMI significantly affected OS (p = 0.004), and positive lymph nodes (PLN) significantly affected both OS (p<0.001) and CSS (p = 0.010).

Conclusions

One-shot neoadjuvant IAC before RC shows safety and tolerability and provides a significant advantage in pathological downstaging but not in OS or CSS. Further study of neoadjuvant combination therapeutic strategies with RC is needed.

Pembrolizumab as Neoadjuvant Therapy Before Radical Cystectomy in Patients With Muscle-Invasive Urothelial Bladder Carcinoma (PURE-01): An Open-Label, Single-Arm, Phase II Study

PURPOSE

To determine the activity of pembrolizumab as neoadjuvant immunotherapy before radical cystectomy (RC) for muscle-invasive bladder carcinoma (MIBC) for which standard cisplatin-based chemotherapy is poorly used.

PATIENTS AND METHODS

In the PURE-01 study, patients had a predominant urothelial carcinoma histology and clinical (c)T≤3bN0 stage tumor. They received three cycles of pembrolizumab 200 mg every 3 weeks before RC. The primary end point in the intention-to-treat population was pathologic complete response (pT0). Biomarker analyses included programmed death-ligand 1 (PD-L1) expression using the combined positive score (CPS; Dako 22C3 pharmDx assay), genomic sequencing (FoundationONE assay), and an immune gene expression assay.

RESULTS

Fifty patients were enrolled from February 2017 to March 2018. Twenty-seven patients (54%) had cT3 tumor, 21 (42%) cT2 tumor, and two (4%) cT2-3N1 tumor. One patient (2%) experienced a grade 3 transaminase increase and discontinued pembrolizumab. All patients underwent RC; there were 21 patients with pT0 (42%; 95% CI, 28.2% to 56.8%). As a secondary end point, downstaging to pT<2 was achieved in 27 patients (54%; 95% CI, 39.3% to 68.2%). In 54.3% of patients with PD-L1 CPS ≥ 10% (n = 35), RC indicated pT0, whereas RC indicated pT0 in only 13.3% of those with CPS < 10% (n = 15). A significant nonlinear association between tumor mutation burden (TMB) and pT0 was observed, with a cutoff at 15 mutations/Mb. Expression of several genes in pretherapy lesions was significantly different between pT0 and non-pT0 cohorts. Significant post-therapy changes in the TMB and evidence of adaptive mechanisms of immune resistance were observed in residual tumors.

CONCLUSION

Neoadjuvant pembrolizumab resulted in 42% of patients with pT0 and was safely administered in patients with MIBC. This study indicates that pembrolizumab could be a worthwhile neoadjuvant therapy for the treatment of MIBC when limited to patients with PD-L1-positive or high-TMB tumors.

Systemic, perioperative management of muscle-invasive bladder cancer and future horizons

Many patients diagnosed with muscle-invasive bladder cancer (MIBC) will develop distant metastatic disease. Over the past three decades, perioperative cisplatin-based chemotherapy has been investigated for its ability to reduce the number of deaths from bladder cancer. Insufficient evidence is available to fully support the use of such chemotherapy in the adjuvant setting; however, neoadjuvant cisplatin-based combination chemotherapy has become a standard of care for eligible patients based on the improved disease-specific and overall survival demonstrated in two randomized phase III trials, compared with surgery alone. For patients with disease downstaging to non-MIBC at the time of radical cystectomy as a result of neoadjuvant chemotherapy, outcomes are outstanding, with 5-year overall survival of 80-90%. Nevertheless, the inability to define before treatment the patients who will and those who will not achieve such a response has impeded the achievement of better outcomes for patients with MIBC. High-throughput DNA and RNA profiling technologies might help to overcome this barrier and enable a more-personalized approach to the use of cytotoxic neoadjuvant chemotherapy. In the past 2 years, trial results have demonstrated the unprecedented ability of immune- checkpoint blockade to induce durable remissions in patients with metastatic disease that has progressed after chemotherapy; studies are now urgently needed to determine how best to incorporate this powerful therapeutic modality into the care of patients with MIBC. Herein, we review the evolution of chemotherapy and immunotherapy for muscle-invasive bladder cancer.

Management of muscle-invasive bladder cancer in the elderly

PURPOSE OF REVIEW

The number of cases of muscle-invasive bladder cancer is increasing along with the age of the population. Management of muscle-invasive bladder cancer in the elderly is complex, requiring a multidisciplinary team approach and a comprehensive assessment of each individual patient.

RECENT FINDINGS

A geriatric assessment should be used to inform treatment decisions in elderly patients with bladder cancer. There is increasing evidence to support aggressive therapy in appropriate elderly patients, including radical cystectomy and neoadjuvant chemotherapy. Adjuvant chemotherapy also has a role in patients with high-risk disease after cystectomy. A bladder preservation approach with trimodality therapy is a well tolerated and effective alternative to cystectomy in appropriately selected patients.

SUMMARY

Treatment decisions should not be based on chronologic age alone and advanced age should not preclude aggressive or curative therapy. The recent molecular characterization of bladder cancer and several recent immunotherapy trials provide hope of a more targeted approach to treatment of bladder, potentially improving both effectiveness and tolerability of treatment regimens in the elderly.

Perioperative and Maintenance Therapy After First-Line Therapy as Paradigms for Drug Discovery in Urothelial Carcinoma

Perioperative chemotherapy provided to increase the chance of cure for localized disease and maintenance therapy for metastatic disease represent 2 distinct aspects of the urothelial cancer disease treatment spectrum. The ability to access both pre- and postchemotherapy tissue in the neoadjuvant setting provides important opportunities for translational research to test novel therapies and identify predictors of response to therapy. The maintenance setting may be more complex, and study design and endpoints need to be determined on the basis of the candidate drugs' mechanisms of action and toxicity.