Chemotherapy is of Value in Second Line and Beyond, Relapsed High-grade, Serous Epithelial Ovarian Cancer: An Analysis of Outcomes Obtained With Oral Etoposide

Effectiveness of oral etoposide in recurrent or refractory epithelial ovarian cancer, primary peritoneal cancer and fallopian tube cancer

The aim of treatment in recurrent or refractory epithelial ovarian cancer is palliation. In a patient with platinum-resistant status, several chemotherapy regimens have been reported with similar response rates. Among these agents, the oral etoposide holds an advantage of the route of administration and management in the out-patient setting. This retrospective study was conducted to evaluate the effectiveness of oral etoposide. Data of patients with recurrent or refractory epithelial ovarian, primary peritoneal and fallopian tube cancer who received oral etoposide treatment in Ramathibodi Hospital, Mahidol University from January 1997 to December 2017 were collected. Progression-free survival (PFS) and overall survival (OS) were primary and secondary outcomes, respectively. The oral etoposide at a dose of 50 mg/m² was prescribed. Sixty-six records were analysed. Median OS and median PFS were 8.3 months (95% confidence interval (CI): 6.8, 10.4) and 3.1 months (95%CI: 2.3, 3.9), respectively. Other factors including age, body mass index (BMI), histopathology subtype, primary treatment, result of the primary surgery, platinum status, site and size of recurrent cancer, treatment after discontinuation of oral etoposide and the line of chemotherapy regimen were not associated with the prognosis. The initial cancer stage was the only independent poor prognostic factor. The main toxicity was neutropenia. Impact StatementWhat is already known on this subject? After the recurrence of epithelial ovarian cancer, peritoneal cancer or fallopian tube cancer, the aim of treatment in this setting is palliation with accentuating on symptomatic control and enhancing the quality of life. According to previous clinical trials, the chemotherapy regimens which were considered as a second-line or beyond the second-line therapy have been reported with similar response rates. Among these agents, the oral etoposide could be administrated by oral route. There were several articles reported the effectiveness of oral etoposide in different dosage.What do the results of this study add? This study adds that administration of oral etoposide at a dose of 50 mg/m² showed fairish oncologic outcomes with manageable toxicity.What are the implications of these findings for clinical practice and/or further research? The results will provide evidence that the oral etoposide can be considerate as a choice of palliative chemotherapy because of an advantage of the route of administration and management in the out-patient setting.

Combination of paclitaxel, bevacizumab and MEK162 in second line treatment in platinum-relapsing patient derived ovarian cancer xenografts

Advanced ovarian cancer is very responsive to first line platinum therapy, however almost invariably it relapses with a resistant disease. We have reported that patient derived ovarian xenografts (PDXs), independently from the degree of the initial response to cisplatin (DDP), show a significantly lower response to a second DDP cycle. We here report the effect of new combination regimens containing a MEK inhibitor (MEK), bevacizumab (BEV) and paclitaxel (PTX) as second line therapy in platinum-relapsing PDXs.

We selected three DDP-relapsing PDX models based on the presence of activation of the RAS/RAF/MEK/ERK axis, mutated p53, lack of PTEN expression and activation of the PI3K pathway. In all the selected xenograft models, the antitumor efficacy of the doublets can be summarized as PTX/BEV > BEV/MEK > PTX/MEK and the antitumor activity of the triple combination was higher than any double combination. All the different combinations were well tolerated. The present data corroborate the activity of bevacizumab in combination with chemotherapy for the treatment of relapsing ovarian tumors and suggest that the addition of another targeted agents (MEK inhibitor) can further increase the antitumor activity without any increase in toxicity. PDX models represent a useful model to test second line therapy after failure of DDP first line.

Targeting multidrug-resistant ovarian cancer through estrogen receptor α dependent ATP depletion caused by hyperactivation of the unfolded protein response

Ovarian cancers often recur and tumors acquire resistance to chemotherapy due to overexpression of the ATP-dependent efflux pump, multidrug resistance protein 1 (MDR1/P-glycoprotein/ABCB1). Nontoxic small molecule inhibitors targeting MDR1 have remained largely elusive. Instead, in a novel application of our recently described estrogen receptor α (ERα) biomodulator, BHPI, we targeted MDR1’s substrate, ATP. BHPI depletes intracellular ATP and nearly blocks MDR1-mediated drug efflux in ovarian cancer cells by inducing toxic hyperactivation of the endoplasmic reticulum stress sensor, the unfolded protein response (UPR). BHPI increased sensitivity of MDR1 overexpressing multidrug resistant OVCAR-3 ovarian cancer cells to killing by paclitaxel by >1,000 fold. BHPI also restored doxorubicin sensitivity in OVCAR-3 cells and in MDR1 overexpressing breast cancer cells. In an orthotopic OVCAR-3 xenograft model, paclitaxel was ineffective and the paclitaxel-treated group was uniquely prone to form large secondary tumors in adjacent tissue. BHPI alone strongly reduced tumor growth. Notably, tumors were undetectable in mice treated with BHPI plus paclitaxel. Compared to control ovarian tumors, after the combination therapy, levels of the plasma ovarian cancer biomarker CA125 were at least several hundred folds lower; moreover, CA125 levels progressively declined to undetectable. Targeting MDR1 through UPR-dependent ATP depletion represents a promising therapeutic strategy.