Predicting the response of patients with advanced urothelial cancer to methotrexate, vinblastine, Adriamycin, and cisplatin (MVAC) after the failure of gemcitabine and platinum (GP)

[Care of advanced or metastatic bladder cancer in second line: A specific place for vinflunine]

Urothelial carcinoma of the bladder are rare but aggressive tumors with a high metastatic potential. The prognosis of these tumors has not drastically changed over the past 30 years, with an overall survival of less than two years in advanced or metastatic situations. Even though immune checkpoints inhibitors have changed this picture, it is beneficial for less than 30% of patients and there is no reliable biomarkers to identify this specific population of responders. Vinflunine is a vinca-alkaloid that was specifically developed as second line treatment post-platinum. As of today, it is the sole anticancer agent for which clinical trials have been pushed to phase III and that was approved for patients in good conditions. Unfortunately, it has been withdrawn from the list of reimbursed drugs, which impairs its prescription. Based on the results of phase III clinical trials with immunotherapies, this review provides the reader with argumentations in favor of patients' and clinicians' request to reimburse vinflunine for the treatment of advanced or metastatic urothelial carcinoma of the bladder.

Applying dynamic contrast enhanced MSOT imaging to intratumoral pharmacokinetic modeling

Examining the dynamics of an agent in the tumor microenvironment can offer critical insights to the influx rate and accumulation of the agent. Intratumoral kinetic characterization in the in vivo setting can further elicudate distribution patterns and tumor microenvironment. Dynamic contrast-enhanced Multispectral Optoacoustic Tomographic imaging (DCE-MSOT) acquires serial MSOT images with the administration of an exogenous contrast agent over time. We tracked the dynamics of a tumor-targeted contrast agent, HypoxiSense 680 (HS680), in breast xenograft mouse models using MSOT. Arterial input function (AIF) approach with MSOT imaging allowed for tracking HS680 dynamics within the mouse. The optoacoustic signal for HS680 was quantified using the ROI function in the ViewMSOT software. A two-compartment pharmacokinetics (PK) model constructed in MATLAB to fit rate parameters. The contrast influx (k_in) and outflux (k_out) rate constants predicted are k_in = 1.96 × 10^-2 s^-1 and k_out = 9.5 × 10^-3 s^-1 (R = 0.9945).

Resistance to nanoparticle albumin-bound paclitaxel is mediated by ABCB1 in urothelial cancer cells

Nanoparticle albumin-bound (nab)-paclitaxel appears to exhibit better response rates in patients with metastatic urothelial cancer of the bladder whom are pretreated with nab-paclitaxel compared with conventional paclitaxel. Paclitaxel may induce multidrug resistance in patients with cancer, while the mechanisms of resistance against paclitaxel are manifold. These include reduced function of pro-apoptotic proteins, mutations of tubulin and overexpression of the drug transporter adenosine 5′-triphosphate-binding cassette transporter subfamily B, member 1 (ABCB1). To evaluate the role of ABCB1 in nab-paclitaxel resistance in urothelial cancer cells, the bladder cancer cell lines T24 and TCC-SUP, as well as sub-lines with acquired resistance against gemcitabine (T24^rGEMCI²⁰ and TCC-SUP^rGEMCI²⁰) and vinblastine (T24^rVBL²⁰ and TCC-SUP^rVBL²⁰) were examined. For the functional inhibition of ABCB1, multi-tyrosine kinase inhibitors with ABCB1-inhibiting properties, including cabozantinib and crizotinib, were used. Additional functional assessment was performed with cell lines stably transduced with a lentiviral vector encoding for ABCB1, and protein expression was determined by western blotting. It was indicated that cell lines overexpressing ABCB1 exhibited similar resistance profiles to nab-paclitaxel and paclitaxel. Cabozantinib and crizotinib sensitized tumor cells to nab-paclitaxel and paclitaxel in the same dose-dependent manner in cell lines overexpressing ABCB1, without altering the downstream signaling of tyrosine kinases. These results suggest that the overexpression of ABCB1 confers resistance to nab-paclitaxel in urothelial cancer cells. Additionally, small molecules may overcome resistance to anticancer drugs that are substrates of ABCB1.

Second-line Chemotherapy in Older Patients With Metastatic Urothelial Carcinoma: Pooled Analysis of 10 Second-line Studies

BACKGROUND

Older patients with metastatic urothelial carcinoma (UC) are under-represented in clinical trials, and data regarding outcomes for second-line therapy is limited.

MATERIALS AND METHODS

Individual data for patients with metastatic UC, aged ≥ 70 years, were pooled from 10 second-line studies. The influence of potential prognostic factors on overall survival (OS) was assessed via univariate and multivariate Cox regression analysis.

RESULTS

In total, 102 patients were included; the median age was 74.0 years (range, 70-88 years). Second-line chemotherapy was single-agent in 42 (41%) patients and combination regimens in 60 (59%) patients. Median progression-free and OS were 4.3 and 9.7 months, respectively. In multivariate analysis, age > 75 years, Eastern Cooperative Oncology Group performance status ≥ 1, serum hemoglobin < 10 g/dL, and non-lymph node only metastasis predicted inferior OS. Median OS for patients with 0, 1, 2, and ≥ 3 adverse factors was unreached, 15.5, 9.8, and 4.8 months, respectively (P < .001). There was no difference in OS between patients treated with single-agent or combination chemotherapy. Combination regimens were associated with higher occurrences of any ≥ grade 2 toxicity (80% vs. 38%; P < .001), ≥ grade 2 hematologic (78% vs. 12%; P < .001), and ≥ grade 2 gastrointestinal toxicity (36% vs. 7%; P < .001).

CONCLUSION

In this pooled analysis of older patients with metastatic UC, combination chemotherapy for second-line treatment was associated with greater toxicity without improvement in OS. Eastern Cooperative Oncology Group performance status ≥1, serum hemoglobin < 10 g/dL, and age > 75 years predicted worse survival, whereas isolated lymph node metastasis predicted a favorable outcome.