Development of a syngeneic mouse model of epithelial ovarian cancer

Background Most cases of ovarian cancer are epithelial in origin and diagnosed at advanced stage when the cancer is widely disseminated in the peritoneal cavity. The objective of this study was to establish an immunocompetent syngeneic mouse model of disseminated epithelial ovarian cancer (EOC) to facilitate laboratory-based studies of ovarian tumor biology and preclinical therapeutic strategies. Methods Individual lines of TgMISIIR-TAg transgenic mice were phenotypically characterized and backcrossed to inbred C57BL/6 mice. In addition to a previously described line of EOC-prone mice, two lines (TgMISIIR-TAg-Low) were isolated that express the oncogenic transgene, but have little or no susceptibility to tumor development. Independent murine ovarian carcinoma (MOVCAR) cell lines were established from the ascites of tumor-bearing C57BL/6 TgMISIIR-TAg transgenic mice, characterized and tested for engraftment in the following recipient mice: 1) severe immunocompromised immunodeficient (SCID), 2) wild type C57BL/6, 3) oophorectomized tumor-prone C57BL/6 TgMISIIR-TAg transgenic and 4) non-tumor prone C57BL/6 TgMISIIR-TAg-Lowtransgenic. Lastly, MOVCAR cells transduced with a luciferase reporter were implanted in TgMISIIR-TAg-Low mice and in vivo tumor growth monitored by non-invasive optical imaging. Results Engraftment of MOVCAR cells by i.p. injection resulted in the development of disseminated peritoneal carcinomatosis in SCID, but not wild type C57BL/6 mice. Oophorectomized tumor-prone TgMISIIR-TAg mice developed peritoneal carcinomas with high frequency, rendering them unsuitable as allograft recipients. Orthotopic or pseudo-orthotopic implantation of MOVCAR cells in TgMISIIR-TAg-Low mice resulted in the development of disseminated peritoneal tumors, frequently accompanied by the production of malignant ascites. Tumors arising in the engrafted mice bore histopathological resemblance to human high-grade serous EOC and exhibited a similar pattern of peritoneal disease spread. Conclusions A syngeneic mouse model of human EOC was created by pseudo-orthotopic and orthotopic implantation of MOVCAR cells in a susceptible inbred transgenic host. This immunocompetent syngeneic mouse model presents a flexible system that can be used to study the consequences of altered gene expression (e.g., by ectopic expression or RNA interference strategies) in an established MOVCAR tumor cell line within the ovarian tumor microenvironment and for the development and analysis of preclinical therapeutic agents including EOC vaccines and immunotherapeutic agents

Weekly vs. Every-3-Week Paclitaxel and Carboplatin for Ovarian Cancer

BACKGROUND A dose-dense weekly schedule of paclitaxel (resulting in a greater frequency of drug delivery) plus carboplatin every 3 weeks or the addition of bevacizumab to paclitaxel and carboplatin administered every 3 weeks has shown efficacy in ovarian cancer. We proposed to determine whether dose-dense weekly paclitaxel and carboplatin would prolong progression-free survival as compared with paclitaxel and carboplatin administered every 3 weeks among patients receiving and those not receiving bevacizumab. METHODS We prospectively stratified patients according to whether they elected to receive bevacizumab and then randomly assigned them to receive either paclitaxel, administered intravenously at a dose of 175 mg per square meter of body-surface area every 3 weeks, plus carboplatin (dose equivalent to an area under the curve [AUC] of 6) for six cycles or paclitaxel, administered weekly at a dose of 80 mg per square meter, plus carboplatin (AUC, 6) for six cycles. The primary end point was progression-free survival. RESULTS A total of 692 patients were enrolled, 84% of whom opted to receive bevacizumab. In the intention-to-treat analysis, weekly paclitaxel was not associated with longer progression-free survival than paclitaxel administered every 3 weeks (14.7 months and 14.0 months, respectively; hazard ratio for disease progression or death, 0.89; 95% confidence interval [CI], 0.74 to 1.06; P=0.18). Among patients who did not receive bevacizumab, weekly paclitaxel was associated with progression-free survival that was 3.9 months longer than that observed with paclitaxel administered every 3 weeks (14.2 vs. 10.3 months; hazard ratio, 0.62; 95% CI, 0.40 to 0.95; P=0.03). However, among patients who received bevacizumab, weekly paclitaxel did not significantly prolong progression-free survival, as compared with paclitaxel administered every 3 weeks (14.9 months and 14.7 months, respectively; hazard ratio, 0.99; 95% CI, 0.83 to 1.20; P=0.60). A test for interaction that assessed homogeneity of the treatment effect showed a significant difference between treatment with bevacizumab and without bevacizumab (P=0.047). Patients who received weekly paclitaxel had a higher rate of grade 3 or 4 anemia than did those who received paclitaxel every 3 weeks (36% vs. 16%), as well as a higher rate of grade 2 to 4 sensory neuropathy (26% vs. 18%); however, they had a lower rate of grade 3 or 4 neutropenia (72% vs. 83%). CONCLUSIONS Overall, weekly paclitaxel, as compared with paclitaxel administered every 3 weeks, did not prolong progression-free survival among patients with ovarian cancer

Adjuvant Chemotherapy in Uterine Leiomyosarcoma: Trends and Factors Impacting Usage

Objectives. The benefit of adjuvant chemotherapy in patients with localized uterine leiomyosarcoma (LMS) remains unclear due to a lack of randomized studies and data only from small retrospective series to rely on. We sought to identify factors associated with the administration of chemotherapy and to determine the trends in the usage of adjuvant chemotherapy in patients with nonmetastatic uterine LMS. Methods. Patients diagnosed with nonmetastatic uterine LMS between 2004 and 2014 were identified from the National Cancer Database (NCDB). Multiple regression was used to determine factors with a significant impact on patient receipt of chemotherapy. Kaplan–Meier curves and the Cox model were used to determine the effect of adjuvant chemotherapy on overall survival (OS). Results. 2,732 uterine LMS patients were identified. Patients older than 65 were less likely to receive chemotherapy than their younger counterparts. Patients with stage I or stage II cancer were less likely to receive chemotherapy, whereas individuals with positive regional lymph nodes and those who had received radiation were more likely. In this cohort, adjuvant chemotherapy had no significant impact on OS (HR, 1.04; 95% CI, 0.90–1.22; P=0.5768). However, administration of chemotherapy significantly increased from 2004 to 2014 (P<0.0001). Conclusions. Expected tumor characteristics such as higher stage of tumor were associated with receipt of chemotherapy. Although adjuvant chemotherapy demonstrated no benefit over observation on OS in patients with nonmetastatic LMS, the number of patients being treated with chemotherapy continued to increase from 2004 to 2014

Safety and activity findings from a phase 1b escalation study of mirvetuximab soravtansine, a folate receptor alpha (FR alpha)-targeting antibody-drug conjugate (ADC), in combination with carboplatin in patients with platinum-sensitive ovarian cancer

PURPOSE: To evaluate the safety profile and preliminary antitumor activity of mirvetuximab soravtansine when administered in combination with carboplatin to relapsed ovarian cancer patients. METHODS: Patients with recurrent, platinum-sensitive epithelial ovarian or fallopian tube cancer were enrolled. Eligibility included a minimum requirement of tumor FRα positivity (≥25% of cells with ≥2+ staining intensity). Patients received escalating doses of mirvetuximab soravtansine and carboplatin on day 1 of a 21-day cycle (once every 3 weeks). Mirvetuximab soravtansine maintenance therapy was permitted, at the investigators discretion, following cessation of carboplatin treatment. Adverse events, tumor response, and progression-free survival (PFS) were determined. RESULTS: Eighteen patients were enrolled and dosed with combination therapy; thirteen continued with mirvetuximab soravtansine maintenance following carboplatin discontinuation. Mirvetuximab soravtansine dosing was escalated from 5 to 6 mg/kg (adjusted ideal body weight) and carboplatin from AUC4 to AUC5. Adverse events were generally mild (≤ grade 2) with nausea, diarrhea, thrombocytopenia, blurred vision, and fatigue being the most common treatment-emergent toxicities. For all evaluable patients (n = 17), the confirmed objective response rate (ORR) was 71%, including three complete responses and nine partial responses, and the median PFS was 15 months. A median duration of response was not reached. CONCLUSION: These data demonstrate that mirvetuximab soravtansine combined with carboplatin is a well-tolerated and highly active regimen in recurrent, platinum-sensitive ovarian cancer. Further evaluation of this combination in a randomized fashion is warranted.status: publishe

Development of a syngeneic mouse model of epithelial ovarian cancer

Abstract Background Most cases of ovarian cancer are epithelial in origin and diagnosed at advanced stage when the cancer is widely disseminated in the peritoneal cavity. The objective of this study was to establish an immunocompetent syngeneic mouse model of disseminated epithelial ovarian cancer (EOC) to facilitate laboratory-based studies of ovarian tumor biology and preclinical therapeutic strategies. Methods Individual lines of TgMISIIR-TAg transgenic mice were phenotypically characterized and backcrossed to inbred C57BL/6 mice. In addition to a previously described line of EOC-prone mice, two lines (TgMISIIR-TAg-Low) were isolated that express the oncogenic transgene, but have little or no susceptibility to tumor development. Independent murine ovarian carcinoma (MOVCAR) cell lines were established from the ascites of tumor-bearing C57BL/6 TgMISIIR-TAg transgenic mice, characterized and tested for engraftment in the following recipient mice: 1) severe immunocompromised immunodeficient (SCID), 2) wild type C57BL/6, 3) oophorectomized tumor-prone C57BL/6 TgMISIIR-TAg transgenic and 4) non-tumor prone C57BL/6 TgMISIIR-TAg-Low transgenic. Lastly, MOVCAR cells transduced with a luciferase reporter were implanted in TgMISIIR-TAg-Low mice and in vivo tumor growth monitored by non-invasive optical imaging. Results Engraftment of MOVCAR cells by i.p. injection resulted in the development of disseminated peritoneal carcinomatosis in SCID, but not wild type C57BL/6 mice. Oophorectomized tumor-prone TgMISIIR-TAg mice developed peritoneal carcinomas with high frequency, rendering them unsuitable as allograft recipients. Orthotopic or pseudo-orthotopic implantation of MOVCAR cells in TgMISIIR-TAg-Low mice resulted in the development of disseminated peritoneal tumors, frequently accompanied by the production of malignant ascites. Tumors arising in the engrafted mice bore histopathological resemblance to human high-grade serous EOC and exhibited a similar pattern of peritoneal disease spread. Conclusions A syngeneic mouse model of human EOC was created by pseudo-orthotopic and orthotopic implantation of MOVCAR cells in a susceptible inbred transgenic host. This immunocompetent syngeneic mouse model presents a flexible system that can be used to study the consequences of altered gene expression (e.g., by ectopic expression or RNA interference strategies) in an established MOVCAR tumor cell line within the ovarian tumor microenvironment and for the development and analysis of preclinical therapeutic agents including EOC vaccines and immunotherapeutic agents.</p