Evaluation of toxicities for intravesical drugs in phase 1 bladder cancer trials.

BACKGROUND: Improving clinical trial design is important for optimizing approval of safe and effective drugs. Phase 1 clinical trials seek to determine phase 2 doses by investigating predefined dose-limiting toxicities. Traditional definitions of dose-limiting toxicity may not be applicable to intravesical therapies for bladder cancer. This study compared the frequency of dose-limiting toxicities and serious adverse events in bladder cancer trials for intravesical therapies to other routes of administration. METHODS: Studies were abstracted from ClinicalTrials.gov and reconciled with a PubMed search. Primary and secondary end points were predefined before data abstraction, and the primary end point was subject-level dose-limiting toxicity rate. Fisher exact tests were performed with p < .05 designated as significant. RESULTS: Eighteen intravesical studies and 24 studies with other routes of administration (the per os/intravenous/intramuscular [PO/IV/IM] group) were identified. Dose-limiting toxicities were reported in 38.9% of intravesical studies, affecting 3.29% of subjects, compared with 30.0% of PO/IV/IM studies representing 4.19% of subjects (p = .52 for study-level and p = .60 for subject-level comparisons). Serious adverse events occurred in 53.9% of intravesical studies in 10.3% of subjects versus 91.0% of studies reporting serious adverse events affecting 41.4% of subjects in the PO/IV/IM group (p = .03 for subject-level and p < .0001 for study-level comparisons). CONCLUSIONS: There was no difference in subject-level dose-limiting toxicity rate between intravesical and PO/IV/IM bladder cancer trials. The serious adverse event rate was lower in the intravesical group. Heterogeneity of dose-limiting toxicity definition may affect interpretation of toxicity in phase 1 bladder cancer clinical trials studying different routes of administration. LAY SUMMARY: Bladder cancer is a common cancer type that may be treated with therapies that are instilled into the bladder and act locally, called intravesical therapies. This study used publicly available regulatory data from early phase clinical trials to determine whether measures of tolerability used in clinical trials are applicable to intravesical therapies for bladder cancer.

Using Grade of Recurrent Tumor to Guide Further Therapy While on Bacillus Calmette-Guerin: Low-grade Recurrences Are not Benign.

BACKGROUND: Tumors that recur after bacillus Calmette-Guerin (BCG) therapy are considered to be of very high risk, and patients are often recommended to undergo radical cystectomy (RC). However, the nuances associated with the grade of tumor recurrence after BCG treatment are not well understood. OBJECTIVE: To characterize the pattern of bladder cancer progression and cancer-specific survival (CSS) in patients with recurrences dichotomized by low grade (LG) versus high grade (HG) after intravesical BCG treatment, and to assess the safety of continued bladder-sparing therapy in these patients. DESIGN, SETTING, AND PARTICIPANTS: We performed an Institutional Review Board-approved review of our bladder cancer database. Overall, 146 non-muscle-invasive bladder cancer (NMIBC) patients were found to have NMIBC recurrence while on BCG therapy; this recurrence was LG in 38 and HG in 108. Baseline clinicopathologic characteristics including age, gender, primary tumor grade, stage, size, multiplicity, and concurrent carcinoma in situ were also evaluated. The primary endpoint was progression-free survival (PFS), with progression defined as the development of muscle-invasive bladder cancer (MIBC)/distant metastasis. In addition, recurrence-free survival (RFS), HG RFS, cystectomy-free survival (CFS), and CSS were also compared. Multivariable analysis was performed using the Cox regression model. All tests were two sided, and p<0.05 was considered statistically significant. INTERVENTION: Further intravesical therapy versus salvage RC. RESULTS AND LIMITATIONS: Overall, estimated 5-yr PFS was 72.4% (95% confidence interval [CI] 60.4-81.3%). As dichotomized by grade of recurrent tumor, PFS was greater for patients with LG recurrences (85.6%, 95% CI 60.8-95.2%) than for those with HG recurrence (67.9%, 95% CI 54.1-78.4%; p=0.010). Furthermore, patients whose initial recurrence on BCG therapy was LG had improved subsequent RFS (median 62 vs 34mo, p=0.007), HG RFS (median 112 vs 36mo, p<0.001), and CFS (estimated 5-yr CFS 80.8% vs 49.8%, p<0.001) compared with those who had HG initial recurrence. On univariate and multivariate analyses, grade of tumor recurrence after BCG was an independent predictor of time to progression to MIBC/distant metastasis (hazard ratio 3.60, 95% CI 1.18-10.94, p=0.024). CONCLUSIONS: Grade of tumor recurrence after intravesical BCG is an important predictor of bladder cancer progression to MIBC/metastatic urothelial carcinoma. While, patients with LG recurrences have less than half the progression events compared with those with HG recurrences, their estimated 5-yr progression rate is still 14.4%. Hence all patients should be carefully counseled on bladder-sparing therapy. This also has implications for clinical trial design. PATIENT SUMMARY: If bladder cancer recurs after bacillus Calmette-Guerin treatment, there are many factors that determine the further clinical outcome. Although low-grade recurrent tumors confer a less aggressive course, disease progression can still occur, and hence continued vigilance is important.

Prognostic Implication of the United States Food and Drug Administration-defined BCG-unresponsive Disease.

The category "BCG-unresponsive disease", formulated by experts at the request of the United States Food and Drug Administration, denotes a group of patients with recurrent non-muscle-invasive bladder cancer for whom continued BCG treatment is unlikely to provide benefit. Although quickly adopted for trial design, many of the nuances within the definition lack validation. In this study, we evaluated the prognostic value of BCG unresponsive designation (i.e. recurrence after induction plus at least 1 maintenance course of BCG) by comparing the oncologic outcomes of these patients with those recurring after induction BCG alone. We confirm that appropriately defined, BCG-unresponsive patients are more likely to require salvage radical cystectomy (54.5% vs 17.9%, p=0.002). Moreover, those opting for second-line bladder-sparing therapies are less likely to remain free of tumor recurrence (23% vs 69.2%, p=0.003). On multivariate analysis, BCG-unresponsive disease independently predicts inferior high-grade recurrence-free survival (hazard ratio [HR]: 6.25, 95% confidence interval [CI]: 2.27-16.67; p<0.001) and cystectomy-free survival (HR: 3.85, 95% CI: 1.49-10.0; p=0.006). Our data confirm the prognostic implication of the BCG unresponsive definition i.e. recurrence of high grade disease after induction and one course of maintenance BCG, and support its use in counseling and risk stratification of patients with tumor recurrence after BCG. Patient summary: Patients who have BCG-unresponsive disease, that is, high-grade non-muscle-invasive bladder cancer recurring after BCG induction and maintenance, have a low likelihood to respond to further BCG treatment and should consider radical cystectomy or clinical trial enrollment.

Systematic Review on the Utilization of Maintenance Intravesical Chemotherapy in the Management of Non-muscle-invasive Bladder Cancer.

CONTEXT: Current guidelines remain ill-defined regarding the optimal intravesical chemotherapy type and regimen for the treatment of non-muscle-invasive bladder cancer (NMIBC). Although maintenance therapy is a standard part of bacillus Calmette-Guerin (BCG) therapy, its role in the context of chemotherapy remains debatable. OBJECTIVE: We reviewed the literature regarding the utilization of intravesical maintenance chemotherapy in the treatment of NMIBC to determine its impact on recurrence, progression, and survival. EVIDENCE ACQUISITION: A systematic search was conducted using Ovid and Medline according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines to identify studies between 1970 and 2018 reporting on the utilization of maintenance intravesical chemotherapy. Only randomized controlled trials (RCTs) that included a comparison between an induction regimen and an induction plus maintenance regimen were included. EVIDENCE SYNTHESIS: Sixteen RCTs were included in the final analysis. The most commonly studied intravesical chemotherapy agents used in maintenance regimens were epirubicin, doxorubicin, and mitomycin C. Several maintenance schedules were utilized, some as short as 3mo and others as long as 3 yr, while the most common maintenance regimen utilized was monthly instillation for 1 yr. Of the 16 trials, 13 reported no significant improvement in recurrence for patients receiving maintenance compared with no maintenance, and none of the trials demonstrated a significant impact on progression or survival. CONCLUSIONS: Intermediate length maintenance regimens lasting 7-12mo were the most common maintenance regimens utilized. There was considerable heterogeneity between trial design and duration of follow-up, making direct comparisons for recurrence, progression, and survival outcomes between trials challenging. Although maintenance intravesical chemotherapy is suggested as a treatment option for patients with NMIBC by some guidelines, the majority of evidence suggested that it provided no significant advantage over induction therapy alone with respect to recurrence, progression, or survival. PATIENT SUMMARY: In this review, we reviewed prior clinical trials to determine whether prolonged intravesical chemotherapy ("maintenance therapy") improved the rates of recurrence, progression, and survival. Where differences were found in favor of maintenance therapy, there was no statistical significance demonstrated, possibly due to the underpowered nature of the study design. While there was no consensus on an optimal agent or maintenance schedule, we found no evidence to suggest that maintenance therapy would improve recurrence, progression, or survival.

HOXB4-transduced embryonic stem cell-derived Lin-c-kit+ and Lin-Sca-1+ hematopoietic progenitors express H60 and are targeted by NK cells.

Embryonic stem (ES) cells are a novel source of cells, especially hematopoietic progenitor cells that can be used to treat degenerative diseases in humans. However, there is a need to determine how ES cell-derived progenitors are regulated by both the adaptive and innate immune systems post transplantation. In this study, we demonstrate that hematopoietic progenitor cells (HPCs) derived from mouse ES cells ectopically expressing HOXB4 fail to engraft long-term in the presence of NK cells. In particular, the H60-expressing Lin(-)c-kit(+) and Lin(-)Sca-1(+) subpopulations were preferentially deleted in Rag2(-/-), but not in Rag2(-/-)gamma(c)(-/-) mice. Up-regulation of class I expression on HPCs prevented their lysis by NK cells, and Ab-mediated depletion of NK cells restored long-term HPC engraftment. In contrast to the notion that ES-derived cells are immune-privileged, we show in this study that NK cells form a formidable barrier to the long-term engraftment of ES cell-derived hematopoietic progenitors.

HOXB4 but not BMP4 confers self-renewal properties to ES-derived hematopoietic progenitor cells.

BACKGROUND: Achieving transplantation tolerance remains an unresolved clinical challenge. Although bone marrow transplantation (BMT) induces mixed chimerism that establishes transplantation tolerance, the preconditioning regimens required for BMT to succeed are too prohibitive for routine use. Recently, embryonic stem (ES) cells have emerged as a potential alternative cell source to bone marrow cells. However, it remains difficult to efficiently differentiate these cells into hematopoietic cells. Here, we tested whether bone morphogenetic protein-4 (BMP-4)-treated or HOXB4-transduced ES-derived hematopoietic cells engraft permanently inducing long-term mixed chimerism. METHODS: Initially, 129 SvJ R1 ES cells (H-2) were treated with BMP-4 for 36 hr. The cells were phenotyped and polymerase chain reaction studies were performed. The robustness of mixed chimerism was tested using mixed lymphocyte cultures and skin grafts. Chimeric MRL (H-2) animals received grafts from 129SvJ (H-2), Balb/c (H-2) or class II (H-2) donor mice, and graft survival was monitored. Additionally, HOXB4-transduced ES cells were shown to more efficiently differentiate into hematopoietic progenitor cells that engrafted in allogenic and syngeneic recipient mice. RESULTS: BMP-4 treatment induced Sca-1 expression and up-regulated HOXB4, BMP-4, and BMP receptor gene expressions. The cells induced transient mixed chimerism, whereas cells derived from HOXB4-transduced ES cells engrafted long term (>100 days). CONCLUSIONS: Although BMP-4 promotes hematopoiesis of ES cells, its impact is only transient, whereas permanent ectopic expression of HOXB4 significantly confers self-renewal and long-term engraftment of ES-derived hematopoietic cells. This strategy could facilitate the establishment of an alternative source of hematopoietic cells that could induce transplantation tolerance.

Soluble HLA revisited.

The goal of this editorial is to revisit soluble human leukocyte antigens (sHLA) and to highlight the findings reported by Albitar et al. in this issue on the relation between sHLA levels in Non-Hodgkin's Lymphoma (NHL) and Hodgkin's Disease (HD). We will review key aspects of sHLA including soluble HLA-G, which has received a lot of attention in recent publications. We will then address the role of sHLA in lymphoproliferative diseases and in solid organ tumors. Lastly, we will comment on the results of Albitar et al. and their relevance to clinical application in NHL.

Suppression of tumor metastasis by blockade of transforming growth factor beta signaling in bone marrow cells through a retroviral-mediated gene therapy in mice.

Transforming growth factor B (TGF-beta) is a potent immunosuppressive cytokine that is frequently associated with mechanisms of tumor escape from immunosurveillance. We report that transplantation of murine bone marrow (BM) expressing a dominant-negative TGF-beta type II receptor (TbetaRIIDN) leads to the generation of mature leukocytes capable of a potent antitumor response in vivo. Hematopoietic precursors in murine BM from donor mice were rendered insensitive to TGF-beta via retroviral expression of the TbetaRIIDN construct and were transplanted in C57BL/6 mice before tumor challenge. After i.v. administration of 5 x 10(5) B16-F10 murine melanoma cells into TbetaRIIDN-BM transplanted recipients, survival of challenged mice at 45 days was 70% (7 of 10) versus 0% (0 of 10) for vector-control treated mice, and surviving TbetaRIIDN-BM mice showed a virtual absence of metastatic lesions in the lung. We also investigated the utility of the TGF-beta-targeted approach in a mouse metastatic model of prostate cancer, TRAMP-C2. Treatment of male C57BL/6 mice with TbetaRIIDN-BM resulted in the survival of 80% (4 of 5) of recipients versus 0% (0 of 5) in green fluorescent protein-BM recipients or wild-type controls. Cytolytic T-cell assays indicate that a specific T-cell response against B16-F10 cells was generated in the TbetaRIIDN-BM-treated mice, suggesting that a gene therapy approach to inducing TGF-beta insensitivity in transplanted BM cells may be a potent anticancer therapy.

Reconstitution of lethally irradiated adult mice with dominant negative TGF-beta type II receptor-transduced bone marrow leads to myeloid expansion and inflammatory disease.

TGF-beta regulation of immune homeostasis has been investigated in the context of cytokine knockout (TGF-beta null) mice, in which particular TGF-beta isoforms are disrupted throughout the entire organism, as well as in B and T cell-specific transgenic models, but to date the immunoregulatory effects of TGF-beta have not been addressed in the context of an in vivo mouse model in which multi-isoform TGF-beta signaling is abrogated in multiple leukocyte lineages while leaving nonhemopoietic tissue unaffected. Here we report the development of a murine model of TGF-beta insensitivity limited to the hemopoietic tissue of adult wild-type C57BL/6 mice based on retroviral-mediated gene transfer of a dominant negative TGF-beta type II receptor targeting murine bone marrow. Unlike the lymphoproliferative syndrome observed in TGF-beta1-deficient mice, the disruption of TGF-beta signaling in bone marrow-derived cells leads to dramatic expansion of myeloid cells, primarily monocytes/macrophages, and is associated with cachexia and mortality in lethally irradiated mice reconstituted with dominant negative receptor-transduced bone marrow. Surprisingly, there was a notable absence of T cell expansion in affected animals despite the observed differentiation of most cells in the T cell compartment to a memory phenotype. These results indicate not only that TGF-beta acts as a negative regulator of immune function, but that lack of functional TGF-beta signaling in the myeloid compartment of adult mice may trigger suppression of lymphocytes, which would otherwise proliferate when rendered insensitive to TGF-beta.