The role of topotecan for extending the platinum-free interval in recurrent ovarian cancer: an in vitro model

Structural and mechanistic basis of substrate transport by the multidrug transporter MRP4

Multidrug resistance-associated protein 4 (MRP4) is an ATP-binding cassette (ABC) transporter expressed at multiple tissue barriers where it actively extrudes a wide variety of drug compounds. Overexpression of MRP4 provides resistance to clinically used antineoplastic agents, making it a highly attractive therapeutic target for countering multidrug resistance. Here, we report cryo-EM structures of multiple physiologically relevant states of lipid bilayer-embedded human MRP4, including complexes between MRP4 and two widely used chemotherapeutic agents and a complex between MRP4 and its native substrate. The structures display clear similarities and distinct differences in the coordination of these chemically diverse substrates and, in combination with functional and mutational analysis, reveal molecular details of the transport mechanism. Our study provides key insights into the unusually broad substrate specificity of MRP4 and constitutes an important contribution toward a general understanding of multidrug transporters.

Pegylated liposomal doxorubicin in patients with epithelial ovarian cancer

OBJECTIVE

To evaluate the efficacy and safety of PLD in treating of in patients who experience epithelial ovarian, fallopian tubal, and peritoneal cancer progression within 12 months after the first-line platinum-based therapy.

METHODS

This was an open-label, single-arm and multicenter clinical trial. The ORR was the interim primary objective, and the DCR, AEs and QOL were the secondary objectives. The impact of factors on efficacy outcomes, the change trend of CA125 and the artificial platinum-free interval were exploratory endpoints.

RESULTS

Totally, 115 patients were enrolled in this study and included in the ITT population. Moreover, 101 patients were included in the safety population. The median follow-up time was 4 months (IQR 2-6). In the ITT population, the confirmed ORR was 37.4% (95% CI, 28.4-46.4%), and the DCR was 65.2% (95% CI, 56.4-74.1%). The previous response status to platinum-based chemotherapy and baseline CA125 levels were significantly correlated with the ORR. The ORR was significantly higher in patients with a CA125 decrease after the first cycle than in the patients with a CA125 increase. The most common grade 3 or higher AE was hand-foot syndrome (3 [3.0%] of 101 patients). No statistically significant differences existed between the baseline and the postbaseline questionnaires.

CONCLUSIONS

For patients who experience platinum-resistant and platinum-refractory relapse, the use of PLD may be acceptable because of the associated satisfactory efficacy, low frequency of AEs and high patient QOL. Moreover, a low CA125 level at baseline and a reduction in CA125 after the first cycle are predictive factors for satisfactory efficacy.

Management of recurrent ovarian cancer: when platinum-based regimens are not a therapeutic option

Ovarian cancer relapses have been traditionally classified according to the platinum-free interval, leading to an arbitrary categorization of possible scenarios and treatment options. Its relevance in assessing treatment strategies has been revised in the last several years, as the panorama is constantly changing in the era of personalized medicine and targeted therapies. Factors to be considered while defining the best management of recurrent disease, and, consequently, the available treatment alternatives are increasing. Platinum remains one of the milestones of ovarian cancer treatment, but for some patients it might not be an ideal choice for several reasons other than limited platinum sensitivity. This review aims to analyze the scenarios in which platinum is not considered suitable in the management of patients with recurrent ovarian cancer, and the currently available alternatives.

Extending the platinum-free interval: The impact of omitting 2nd line platinum chemotherapy in intermediate platinum-sensitive ovarian cancer

OBJECTIVES

Patients with epithelial ovarian cancer (EOC) recurring between 6 and 12 months after primary platinum chemotherapy have worse prognosis than those recurring in >12 months. Artificially prolonging the platinum-free interval (PFI) with cytotoxic chemotherapy was tested in MITO-8 with poor outcomes. This study aimed to determine the impact of using non-platinum or targeted therapy in 2nd line treatment of EOC patients recurring 6-12 months after completion of primary platinum-based chemotherapy.

METHODS

A multi-institutional retrospective review of 177 patients with recurrent EOC and PFI of 6-12 months following primary chemotherapy was performed comparing platinum versus non-platinum chemotherapy or targeted therapy for 2nd line treatment. PFI1 was defined as the date of last chemotherapy to date of recurrence. PFS2/3 were defined as start of 2nd or 3rd line chemotherapy to start of subsequent line.

RESULTS

Of 177 patients, the majority of patients were Caucasian, had serous histology, and underwent primary cytoreductive surgery. Median PFI1 was 8.2 months (95% CI 8-9 months). Second line platinum was omitted in 28% of patients. Bevacizumab was used in 2nd line in 16% of patients; 19% received other targeted therapies. Median PFS2 for platinum chemotherapy was longer than non-platinum (7.1 vs 3 months, p = 0.0114). Median PFS2 was significantly longer for platinum vs. targeted therapy (7.1 vs. 3 months p = 0.0431). Median OS for platinum in 2nd line vs. no platinum was 43.6 vs. 37.6 months (p = 0.0174).

CONCLUSIONS

Use of non-platinum chemotherapy and even targeted therapy to prolong PFI in patients with EOC recurring between 6 and 12 months leads to worse survival.

Phase I/Ib study of olaparib and carboplatin in heavily pretreated recurrent high-grade serous ovarian cancer at low genetic risk

Purpose: To investigate maximum tolerated dose (MTD), activity and predictive biomarkers of olaparib with carboplatin in BRCA wild-type (BRCAwt) high grade serous ovarian carcinoma (HGSOC) patients. Methods: A 3+3 dose escalation study examined olaparib capsules (400 mg twice daily [BID], days 1-7) with carboplatin (AUC3-5 on day 1) every 21 days for 8 cycles, followed by olaparib 400 mg BID maintenance. Blood and tumor biopsy samples were collected pre- and on-treatment in the expansion cohort for PAR levels and proteomic endpoints. Results: 30 patients (median 7 prior regimens [2-12], 63% (19/30) platinum-resistant) were enrolled. Dose-limiting toxicity was thrombocytopenia/neutropenia, and infection with carboplatin AUC5 (2/6 patients). MTD was olaparib 400 mg BID + carboplatin AUC4. Grade 3/4 adverse events (>10%) included neutropenia (23%), thrombocytopenia (20%), and anemia (13%). Five of 25 (20%) evaluable patients had partial response (PR; median 4.5 months [3.3-9.5]). Clinical benefit rate (PR + stable disease ≥4 months) was 64% (16/25). A greater decrease in tissue PAR levels was seen in the clinical benefit group versus no benefit (median normalized linear change -1.84 [-3.39- -0.28] vs 0.51 [-0.27- 1.29], p = 0.001) and a DNA repair score by proteomics did not correlate with response. Conclusions: The olaparib and carboplatin combination is tolerable and has clinical benefit in subsets of heavily pretreated BRCAwt HGSOC, independent of platinum sensitivity.

Pegylated liposomal doxorubicin re-challenge in patients with ovarian cancer relapse: a multicenter retrospective study

Background

Pegylated liposomal doxorubicin (PLD) is an active and well-tolerable treatment in ovarian cancer relapse, either alone or in combination with other drugs. No data are available on the possibility to rechallenge PLD treatment in long survivor patients with recurrent ovarian cancer, as evaluated for platinum agent, paclitaxel and gemcitabine. The aim of the present study was to evaluate the anti-tumor activity and the toxicity profile of re-challenge of PLD in recurrent ovarian cancer patients.

Methods

Data on 27 patients with epithelial ovarian cancer treated in the last ten years (2007-2017) with palliative PLD rechallenge were included in this multicenter retrospective Italian study.

Results

The objective response rate to PLD re-treatment were complete response in 19%, partial response in 30% and stable disease in 37%. Only 1 case of G4 hematological toxicity was reported. No patient experienced severe cardiac impairment (G2-4).

Conclusion

PLD rechallenge represents an active and safe possibility of treatment for long survivor ovarian cancer patients.

Trabectedin for reversing platinum resistance and resensitization to platinum in patients with recurrent ovarian cancer

Aims: We evaluated trabectedin in patients with platinum-resistant/refractory and partially platinum-sensitive recurrent ovarian cancer and the outcomes after reintroduction of platinum. Methods: Twenty-seven patients (platinum-resistant/refractory n = 24/PPS; n = 3) treated with trabectedin were retrospectively analyzed. Results: Trabectedin resulted in an objective response rate (ORR) of 18.2% with a 59.1% of disease control rate (ORR plus stable disease). The median progression-free and overall survival were 3.0 and 21.3 months, respectively. Subsequently, 17 patients were retreated with platinum and yield an ORR of 41.2% and DCR of 47.0%. The median progression-free and overall survival after platinum rechallenge were 5.0 and 14.7 months, respectively. Conclusion: Our results suggest that trabectedin may contribute to resensitize tumor cells to platinum rechallenge.

Trabectedin mechanism of action and platinum resistance: molecular rationale

Trabectedin presents a complex mode of action affecting key cell biology processes in tumor cells and in the tumor microenvironment. In ovarian cancer patients with a platinum treatment-free interval of 6–12 months treated with trabectedin + pegylated liposomal doxorubicin (PLD) or single-agent PLD, and retreated with platinum after relapse, overall survival was significantly prolonged in the trabectedin + PLD group. Mechanisms by which trabectedin restores tumor sensitivity to platinum include its interaction with components of the nucleotide excision repair machinery in tumor cells and inhibition of inflammatory mediators such as IL-6 in the tumor microenvironment. Additionally, BRCA mutations and associated homologous recombination repair deficiency may contribute to enhanced sensitivity to trabectedin observed in BRCA-mutated patients with ovarian cancer.

When nonplatinum is the answer: the role of trabectedin plus pegylated liposomal doxorubicin in recurrent ovarian cancer

Trabectedin + pegylated liposomal doxorubicin (PLD) offers a well tolerated and effective nonplatinum, nontaxane alternative for treatment of ovarian cancer patients with a treatment-free interval after platinum beyond 6 months, especially for those relapsing between 6 and 12 months and those who are not candidates to receive platinum-based therapy. Using the nonplatinum trabectedin + PLD combination gives patients time to recover from platinum-related toxicities and may restore platinum sensitivity in tumor cells. The sequence effect, by which intercalation of trabectedin + PLD between platinum regimens may enhance the activity of next platinum and improve survival, is currently under investigation in the Phase III prospective INternational OVArian cancer patients Trial with YONdelis.

The HDACi Panobinostat Shows Growth Inhibition Both In Vitro and in a Bioluminescent Orthotopic Surgical Xenograft Model of Ovarian Cancer

Background

In most epithelial ovarian carcinomas (EOC), epigenetic changes are evident, and overexpression of histone deacetylases (HDACs) represents an important manifestation. In this study, we wanted to evaluate the effects of the novel HDAC inhibitor (HDACi) panobinostat, both alone and in combination with carboplatin, on ovarian cancer cell lines and in a murine bioluminescent orthotopic surgical xenograft model for EOC.

Methods

The effects of panobinostat, both alone and in combination with carboplatin, on proliferation and apoptosis in ovarian cancer cell lines, were evaluated using colony and WST-1 assays, Hoechst staining and flow cytometry analysis. In addition, mechanisms were characterised by western blotting and phosphoflow analysis. Immuno-deficient mice were engrafted orthotopically with SKOV-3^luc+ cells and serial bioluminescence imaging monitored the effects of treatment with panobinostat and/or carboplatin and/or surgery. Survival parameters were also measured.

Results

Panobinostat treatment reduced cell growth and diminished cell viability, as shown by the induced cell cycle arrest and apoptosis in vitro. We observed increased levels of cleaved PARP and caspase-3, downregulation of cdc2 protein kinase, acetylation of H2B and higher pH2AX expression. The combined administration of carboplatin and panobinostat synergistically increased the anti-tumour effects compared to panobinostat or carboplatin treatment alone. In our novel ovarian cancer model, the mice showed significantly higher rates of survival when treated with panobinostat, carboplatin or a combination of both, compared to the controls. Panobinostat was as efficient as carboplatin regarding prolongation of survival. No significant additional effect on survival was observed when surgery was combined with carboplatin/panobinostat treatment.

Conclusions

Panobinostat demonstrates effective in vitro growth inhibition in ovarian cancer cells. The efficacy of panobinostat and carboplatin was equal in the orthotopic EOC model used. We conclude that panobinostat is a promising therapeutic alternative that needs to be further assessed for the treatment of EOC.

Treatment options in recurrent ovarian cancer: latest evidence and clinical potential

Ovarian cancer (OC) is the fifth most common cause of cancer death in women. Although significant progress has been made in the treatment of OC, the majority of patients experience disease recurrence and receive second-line and sometimes several lines of treatment. Here we review the options available for the treatment of recurrent disease and discuss how different agents are selected, combined and offered in a rationale sequence in the context of multidisciplinary care. We reviewed published work between 1990 and 2013 and meeting abstracts related to the use of chemotherapy and surgery in patients with recurrent ovarian cancer. We discuss treatment regimens, efficacy endpoints and safety profiles of the different therapies. Platinum-based drugs are the most active agents and are selected on the basis of a probability of response to retreatment. Nonplatinum-based chemotherapy regimens are usually given in the 'platinum-resistant' setting and have a modest effect on outcome. Molecular targeted therapy of ovarian cancer given alone or integrated with chemotherapy is showing promising results. Many patients are now receiving more than one line of therapy for recurrent disease, usually platinum based until platinum resistance emerges. The sequential use of chemotherapy regimens and the incorporation of molecularly targeted treatments, either alone or in combination with chemotherapy, have over the last decade significantly extended the median survival of patients with ovarian cancer.

Pegylated liposomal doxorubicin in the management of ovarian cancer: a systematic review and metaanalysis of randomized trials

Ovarian cancer is the leading cause of death among gynecological tumors. Carboplatin/paclitaxel represents the cornerstone of front-line treatment. Instead, there is no consensus for management of recurrent/progressive disease, in which pegylated liposomal doxorubicin (PLD) ± carboplatin is widely used. We performed a systematic review and metaanalysis to evaluate impact of PLD-based compared with no-PLD-based regimens in the ovarian cancer treatment. Data were extracted from randomized trials comparing PLD-based treatment to any other regimens in the January 2000-January 2013 time-frame. Study end-points were overall survival (OS), progression free survival (PFS), response rate (RR), CA125 response, and toxicity. Hazard ratios (HRs) of OS and PFS, with 95% CI, odds ratios (ORs) of RR and risk ratios of CA125 response and grade 3-4 toxicity, were extracted. Data were pooled using fixed and random effect models for selected endpoints. Fourteen randomized trials for a total of 5760 patients were selected and included for the final analysis, which showed no OS differences for PLD-based compared with other regimens (pooled HR: 0.94; 95% CI: 0.88-1.02; P = 0.132) and a significant PFS benefit of PLD-based schedule (HR: 0.91; 95% CI: 0.86-0.96; P = 0.001), particularly in second-line (HR: 0.85; 95% CI: 0.75-0.91) and in platinum-sensitive (HR: 0.83; 95% CI: 0.74-0.94) subgroups. This work confirmed the peculiar tolerability profile of this drug, moreover no difference was observed for common hematological toxicities and for RR, CA125 response. PLD-containing regimens do not improve OS when compared with any other schedule in all phases of disease. A marginal PFS advantage is observed only in platinum-sensitive setting and second-line treatment.

In vitro moxifloxacin drug interaction with chemotherapeutics: implications for retinoblastoma management

Retinoblastoma (RB) is a common malignant intraocular tumor primarily affecting children. Multidrug resistance (MDR) proteins (P-gp and MRPs) mediated chemoresistance have been considered as a major cause of treatment failure in treatment of RB. Ocular cells have shown good tolerability against moxifloxacin (MFX). Hence, the aim of present study was to investigate the effect of moxifloxacin on the functionality of MDR proteins. Furthermore, we have also examined an interaction of MFX with anticancer agents (Topotecan, etoposide and vinblastine) for RB treatment. For interaction of MFX with efflux transporter, model cell lines transfected with the efflux transporters (MDCK-MDR1 and MDCK-MRP2) were used to perform uptake and bi-directional transport experiments. Modulation of anticancer induced cell cytotoxicity, pro-inflammatory cytokines (IL-6 and IL-8) release and caspase-3 enzyme activity in presence of MFX was also evaluated. Result indicates that MFX is a substrate of both MDR1 and MRP2 efflux transporters. Furthermore elevation of anticancer uptake and bi-directional transport, reduction in IC50 cytotoxic value and modulation of antiproliferative and cytokines release in presence of MFX by anticancer agents was observed. Our results demonstrate that MFX may not only modulate the permeability of anticancer agents at efflux sites but it may also potentiate antiproliferative activity of anticancer agents in retinoblastoma cells. This study may be further extended to explore in vivo outcome of this finding.

Trabectedin plus pegylated liposomal doxorubicin in the treatment of patients with partially platinum-sensitive ovarian cancer: current evidence and future perspectives

The effectiveness of platinum re-treatment in relapsed ovarian cancer depends on relapse-free/treatment-free intervals. Platinum agents can be effectively readministered to platinum-sensitive patients (relapsing >12 months after platinum), but efficacy is lower in partially platinum-sensitive (PPS) disease (relapsing 6-12 months after platinum). There is no clear standard treatment challenging PPS patients. Survival data in this subset with chemotherapy combinations such as pegylated liposomal doxorubicin (PLD) plus carboplatin or gemcitabine plus PLD are available from phase II trials ranging from 16 to 21 months. Recent results from OVA-301 phase III randomized trial evaluating trabectedin plus PLD showed the longest median overall survival ever reported in PPS patients (23 months). Subsequent chemotherapy (including platinum-based regimens) was administered later and survival in patients receiving third-line platinum was longer in patients treated with trabectedin plus PLD compared with those treated with PLD alone. These results suggest that prolonging platinum-free interval (PFI) with an effective non-platinum regimen improves outcome with subsequent third-line platinum treatment. An ongoing phase III trial (INOVATYON) aims to demonstrate if the results observed with trabectedin plus PLD in PPS patients are due to PFI extension, and if PFI extension with non-platinum combination prolongs response to subsequent platinum and survival in this population.

A multicenter, randomized, phase 2 clinical trial to evaluate the efficacy and safety of combination docetaxel and carboplatin and sequential therapy with docetaxel then carboplatin in patients with recurrent platinum-sensitive ovarian cancer

BACKGROUND

The aim of this randomized clinical trial was to evaluate the efficacy and safety of combination (cDC) and sequential (sDC) weekly docetaxel and carboplatin in women with recurrent platinum-sensitive epithelial ovarian cancer (EOC).

METHODS

Participants were randomized to either weekly docetaxel 30 mg/m(2) on days 1 and 8 and carboplatin area under the curve (AUC) = 6 on day 1, every 3 weeks or docetaxel 30 mg/m(2) on days 1 and 8, every 3 weeks for 6 cycles followed by carboplatin AUC = 6 on day 1, every 3 weeks for 6 cycles or until disease progression. The primary endpoint was measurable progression-free survival (PFS).

RESULTS

Between January 2004 and March 2007, 150 participants were enrolled. The response rate was 55.4% and 43.2% for those treated with cDC and sDC, respectively. The median PFS was 13.7 months (95% confidence interval [CI], 9.9-16.8) for cDC and 8.4 months (95% CI, 7.1-11.0) for sDC. On the basis of an exploratory analysis, patients treated with sDC were at a 62% increased risk of disease progression compared to those treated with cDC (hazard ratio = 1.62; 95% CI, 1.08-2.45; P = .02). The median overall survival time was similar in both groups (33.2 and 30.1 months, P = .2). The incidence of grade 2 or 3 neurotoxicity and grade 3 or 4 neutropenia was higher with cDC than with sDC (11.7% vs 8.5%; 36.8% vs 11.3%). The sDC group demonstrated significant improvements in the Functional Assessment for Cancer Therapy-Ovarian, Quality of Life Trial Outcome Index scores compared with the combination cohort (P = .013).

CONCLUSIONS

Both cDC and sDC regimens have activity in recurrent platinum-sensitive EOC with acceptable toxicity profiles. The cDC regimen may provide a PFS advantage over sDC.

Benefits of enhancing the platinum-free interval in the treatment of relapsed ovarian cancer: more than just a hypothesis?

There is some evidence from in vitro studies as well as case series that patients with documented platinum resistance will respond to platinum after a nonplatinum drug. In addition, retrospective case studies have demonstrated the difficulty in determining if delaying second platinum is detrimental or beneficial. For that reason, a prospective Italian randomized trial conducted by the Multicenter Italian Trials in Ovarian Cancer (MITO) Group (MITO-8), comparing nonplatinum with platinum-based therapy is being performed to assess the effects of delaying platinum on survival.

Trabectedin plus pegylated liposomal doxorubicin in relapsed ovarian cancer delays third-line chemotherapy and prolongs the platinum-free interval

BACKGROUND

OVA-301 is a large randomized trial that showed superiority of trabectedin plus pegylated liposomal doxorubicin (PLD; CentoCor Ortho Biotech Products L.P., Raritan, NJ, USA). over single-agent PLD in 672 patients with relapsed ovarian cancer, particularly in the partially platinum-sensitive subgroup [platinum-free interval (PFI) of 6-12 months]. This superiority has been suggested to be due to the differential impact of subsequent (platinum) therapy.

PATIENTS AND METHODS

a detailed analysis of subsequent therapies and survival outcomes in the overall population and in the subsets according to platinum sensitivity was therefore conducted.

RESULTS

similar proportions of patients received subsequent therapy in each arm (76% versus 77%), including further platinum-based regimens (49% versus 55%). Patients in the trabectedin/PLD arm received subsequent chemotherapy at a later time (median delay 2.5 months versus PLD arm). Overall survival from subsequent platinum was significantly prolonged in the partially platinum-sensitive disease subset (hazard ratio = 0.63; P = 0.0357).

CONCLUSION

the superiority of trabectedin/PLD over single-agent PLD in OVA-301 cannot be explained by differences in the extent or nature of subsequent therapies administered to these patients. On the other hand, these exploratory analyses support the hypothesis that the enhanced survival benefits in the partially platinum-sensitive subset might be due to an extended PFI leading to longer survival with subsequent platinum.

Trabectedin plus pegylated liposomal doxorubicin in relapsed ovarian cancer: outcomes in the partially platinum-sensitive (platinum-free interval 6-12 months) subpopulation of OVA-301 phase III randomized trial

BACKGROUND

OVA-301 is a large randomized trial that showed superiority of trabectedin plus pegylated liposomal doxorubicin (PLD) over PLD alone in relapsed ovarian cancer. The optimal management of patients with partially platinum-sensitive relapse [6-12 months platinum-free interval (PFI)] is unclear.

PATIENTS AND METHODS

within OVA-301, we therefore now report on the outcomes for the 214 cases in this subgroup.

RESULTS

Trabectedin/PLD resulted in a 35% risk reduction of disease progression (DP) or death [hazard ratio (HR) = 0.65, 95% confidence interval (CI), 0.45-0.92; P = 0.0152; median progression-free survival (PFS) 7.4 versus 5.5 months], and a significant 41% decrease in the risk of death (HR = 0.59; 95% CI, 0.43-0.82; P = 0.0015; median survival 23.0 versus 17.1 months). The safety of trabectedin/PLD in this subset mimicked that of the overall population. Similar proportions of patients received subsequent therapy in each arm (76% versus 77%), although patients in the trabectedin/PLD arm had a slightly lower proportion of further platinum (49% versus 55%). Importantly, patients in the trabectedin/PLD arm survived significantly longer after subsequent platinum (HR = 0.63; P = 0.0357; median 13.3 versus 9.8 months).

CONCLUSION

This hypothesis-generating analysis demonstrates that superior benefits with trabectedin/PLD in terms of PFS and survival in the overall population appear particularly enhanced in patients with partially sensitive disease (PFI 6-12 months).

Feasibility of extension of platinum-free interval with weekly bolus topotecan and subsequent platinum retreatment outcomes in recurrent ovarian cancer

PURPOSE

The goal of this study was to evaluate the outcomes and response in a cohort of patients with presumed platinum-sensitive disease who were subsequently retreated with platinum after receiving weekly bolus topotecan at the time of initial recurrence.

METHODS

A retrospective review of our institutional databases identified a cohort of platinum-sensitive women with recurrent ovarian and peritoneal carcinoma. Antitumor responses and toxicities were assessed for patients retreated with platinum-based chemotherapy following weekly bolus topotecan (4 mg/m²).

RESULTS

Twenty-six patients (median age 63 years, range 45-80 years) were identified. Advanced stage (III/IV) ovarian carcinoma was most common (96%). Residual disease after primary cytoreductive surgery was less than 1 cm in 65% of the cohort. Platinum retreatment was well tolerated. Grade 3 neutropenia occurred most commonly (8%) without any episodes of grade 4 myelotoxicity. Fatigue (12%) and hypersensitivity reaction (15%) were the most common non-hematologic toxicities during platinum retreatment. Of the 26 patients, 5 (19%) had a complete response, 5 (19%) had a partial response, 10 (39%) had stable disease, and 6 (23%) had progressive disease. Thirty-nine percent of patients with stable or progressive disease during weekly bolus topotecan responded to subsequent platinum retreatment. Response to platinum retreatment, treatment-free interval, and platinum-free interval was significant prognosticators for survival (P < 0.05).

CONCLUSION(S)

The results of this retrospective analysis suggest that weekly bolus topotecan, as intervening non-platinum, may result in acceptable toxicities and response rates during platinum retreatment in platinum-sensitive relapsed ovarian or peritoneal carcinoma.

Apoptotic and chemotherapeutic properties of iron (III)-salophene in an ovarian cancer animal model

The cytotoxicity of organometallic compounds iron(III)-, cobalt(III)-, manganese(II)-, and copper(II)-salophene (-SP) on platinum-resistant ovarian cancer cell lines was compared. Fe-SP displayed selective cytotoxicity (IC(50) at ~1 muM) against SKOV-3 and OVCAR-3 cell lines while Co-SP caused cytotoxic effects only at higher concentrations (IC(50) at 60 muM) and Cu-SP effects were negligible. High cytotoxicity of Mn-SP (30-60 muM) appeared to be nonspecific because the Mn-chloride salt reduced cell viability similarly. The effect of Fe-SP at 1 muM proved to be ovarian cancer cell selective when compared to a panel of cell lines derived from different tumors. The first irreversible step in the induction of cell death by Fe-SP occurred after 3 hrs as indicated by the mitochondrial transmembrane potential (DeltaPsim) and was mainly linked to apoptotic, not necrotic events. To evaluate the toxicity of Fe-SP in vivo we conducted an acute toxicity study in rats. The LD(50) of Fe-SP is >2000 mg/kg orally and >5.5 mg/kg body weight by intraperitoneal injection. An ovarian cancer animal model showed that the chemotherapeutic relevant dose of Fe-SP in rats is 0.5-1 mg/kg body weight. The present report suggests that Fe-SP is a potential therapeutic drug to treat ovarian cancer.

Treatment of recurrent epithelial ovarian cancer

Epidemiologic analysis reveals that the mortality rate from ovarian cancer is continuously decreasing due to the improvement of surgery and chemotherapy. However, the prognosis of ovarian cancer patients is still unsatisfactory overall considering that only 30% of patients are alive after five years. In fact, although surgery and first-line systemic chemotherapy induces complete and partial response in up to 80% of patients with about a 25% pathological complete remission rate, recurrences occur in the majority of patients. The role of surgery in recurrent disease has been recently studied and many patients can receive an optimal secondary cytoreduction. Most of the recurrent patients are subject to a number of treatment regimens that, although palliative in nature, are also able to prolong survival. Important results have been obtained in particular in platinum-sensitive recurrent disease where a platinum-based chemotherapy is able to prolong progression-free survival and overall survival. Overall, our armamentarium for the treatment of progressive or recurrent ovarian cancer is significantly richer than in the past, and in many patients it is possible to achieve our goal of controlling the chronic behavior of the disease.

Prognostic factors associated with response in platinum retreatment of platinum-resistant ovarian cancer

The goal of this study was to determine the factors associated with response to platinum retreatment in patients with platinum-resistant ovarian cancer. A review of patients with epithelial ovarian cancer retreated with cisplatin or carboplatin between 2002 and 2004 was performed. The platinum-free interval (PFI) and treatment-free interval (TFI) were determined for each patient. Response was based on serial CA125 levels using a modification of the Rustin criteria. Patients with clinical benefit ([CB] those who attained at least stable disease) were compared to patients with disease progression (PD). An analysis was performed to determine factors associated with CB in platinum-resistant patients retreated with platinum. Of 48 patients identified, 37 were evaluable included in this analysis. CB was observed in 27 (73%) while disease progression was noted in 10 (27%) women. The PFI was longer in those women who achieved CB (12.3 vs 6.9 months; P = 0.02). The TFI was 7.1 months for patients benefited from platinum retreatment vs 3.5 months for those with disease progression (P = 0.06). There was no statistically significant difference in the number of cytotoxic agents between the time of platinum retreatment and the prior platinum regimen (2 vs 1.5 months; P = 0.61). A prolonged PFI was associated with an improved chance of achieving CB with platinum retreatment. There was no association between the response to platinum retreatment and the number of intervening cytotoxic agents utilized. Further prospective study is warranted to define the optimal timing of platinum retreatment.

Update in the management of ovarian and cervical carcinoma

Ovarian and cervical cancers are significant health problems. This article provides an update in selected management topics. Paclitaxel and platinum derivatives are the first-line treatment for patients with advanced disease. In selected patients, intraperitoneal chemotherapy has been associated with improved survival but the broad applicability of this strategy is limited by issues of toxicity and feasibility. Management of patients with recurrent disease is based on a number of factors and includes surgery in selected cases, platinum-based chemotherapy for patients with platinum-sensitive disease and other agents such as topotecan and pegylated liposomal formulation of doxorubicin for patients with platinum-resistant disease. In cervical cancer, the most significant issue/event is the demonstration of superior survival with topotecan and cisplatin compared to cisplatin alone. Finally, new agents such as epidermal growth factor receptor inhibitors and antiangiogenic agents are being currently tested in these settings.

Anticancer drugs induce mdr1 gene expression in recurrent ovarian cancer

Ovarian cancer is currently the most lethal gynecologic malignancy in Europe and the US. Platin analogues and paclitaxel demonstrate high remission rates, but unfortunately the efficacy of cytostatic agents is limited by the development of multidrug resistance (mdr). Clinical paclitaxel resistance is often associated with mdr1 overexpression. In a recent study, we introduced a highly specific quantitative real-time reverse transcriptase polymerase chain reaction for the quantification of mdr1 transcripts. In the present study, we demonstrate that primary tumor cells from patients with recurrent ovarian cancer overexpress mdr1. To evaluate mdr1 expression, we collected tumor cells from 77 ovarian cancer patients (13 chemotherapy-naive ovarian cancer, 64 recurrent ovarian cancer). Cancer cells were aspirated from 49 solid specimens (63%) and 28 ascitic fluids (37%). Subsequently, cancer cells were exposed in 221 short-term cultures either to blank medium (control) or to a single anticancer drug, cisplatin, doxorubicin or paclitaxel. The drug concentrations applied referred to clinical relevant doses. mdr1 mRNA expression was significantly higher in specimens from recurrent ovarian cancer incubated in paclitaxel than in specimens from chemotherapy-naive ovarian cancer. No significant differences were detectable between the mean value of mdr1 mRNA expression in tumor specimens from recurrent ovarian cancer incubated in cisplatin or doxorubicin. Differences within the untreated patients group were also not statistically significant. The result of this study confirms clinical observations, as well as in-vitro studies based on tumor cell lines, that paclitaxel resistance is correlated with mdr1 overexpression.

Population Pharmacokinetic-Pharmacodynamic Model for Neutropenia with Patient Subgroup Identification: Comparison across Anticancer Drugs

PURPOSE

Cancer chemotherapy, although based on body surface area, often causes unpredictable myelosuppression, especially severe neutropenia. The aim of this study was to evaluate qualitatively and quantitatively the influence of patient-specific characteristics on the neutrophil concentration-time course, to identify patient subgroups, and to compare covariates on system-related pharmacodynamic variable between drugs.

EXPERIMENTAL DESIGN

Drug and neutrophil concentration, demographic, and clinical chemistry data of several trials with docetaxel (637 patients), paclitaxel (45 patients), etoposide (71 patients), or topotecan (191 patients) were included in the covariate analysis of a physiology-based pharmacokinetic-pharmacodynamic neutropenia model. Comparisons of covariate relations across drugs were made.

RESULTS

A population model incorporating four to five relevant patient factors for each drug to explain variability in the degree and duration of neutropenia has been developed. Sex, previous anticancer therapy, performance status, height, binding partners, or liver enzymes influenced system-related variables and alpha1-acid glycoprotein, albumin, bilirubin, concomitant cytotoxic agents, or administration route changed drug-specific variables. Overall, female and pretreated patients had a lower baseline neutrophil concentration. Across-drug comparison revealed that several covariates (e.g., age) had minor (clinically irrelevant) influences but consistently shifted the pharmacodynamic variable in the same direction.

CONCLUSIONS

These mechanistic models, including patient characteristics that influence drug-specific parameters, form the rationale basis for more tailored dosing of individual patients or subgroups to minimize the risk of infection and thus might contribute to a more successful therapy. In addition, nonsignificant or clinically irrelevant relations on system-related parameters suggest that these covariates could be negligible in clinical trails and daily use.

Paclitaxel modifies the accumulation of tumor-diagnostic tracers in different ways in P-glycoprotein-positive and negative cancer cells

AIM

To study how paclitaxel treatment modifies the accumulation of tumor-diagnostic radiotracers in P-glycoprotein (P-gp) positive and negative cancer cells.

METHODS

The accumulations of different P-gp substrates, including rhodamine 123, daunorubicin and [(99m)Tc]hexakis-2-methoxybutyl isonitrile ((99m)Tc-MIBI), were measured in P-gp-positive (A2780AD) and P-gp-negative human ovarian carcinoma cells (A2780) and JY human lymphoid B cells. The uptakes of the tumor-diagnostic tracers (11)C-choline and 2-[(18)F]fluoro-2-deoxy-d-glucose ((18)FDG) were measured in the same cell lines. The P-gp expression and function were demonstrated by flow-cytometry.

RESULTS

The (18)FDG measurements revealed that the glucose metabolic rate was significantly higher (p<0.01) in the P-gp-positive A2780AD cells than in the P-gp-negative cells. Paclitaxel (1-70microM) increased the (18)FDG uptake (up to 200%) of both P-gp-positive and P-gp-negative cells, whereas it did not modulate their (11)C-choline uptake. Paclitaxel reinstated the (99m)Tc-MIBI accumulation of the A2780AD cells (to 1500% of the control) in a concentration-dependent manner, while it increased the uptake of the P-gp-negative cells to a lesser extent (to a maximum of 200% of the control).

CONCLUSION

Paclitaxel modifies the uptake of tumor-diagnostic tracers in both P-gp-dependent and independent manners. Interpretation of the multifactorial effects of paclitaxel may promote a correct in vivo diagnosis of P-gp-positive and P-gp-negative tumors.

Psychological stress induces chemoresistance in breast cancer by upregulating mdr1

Psychological distress reduces the efficacy of chemotherapy in breast cancer patients. The mechanism may be related to the altered neuronal or hormonal secretions during stress. Here, we reported that adrenaline, a hormone mediating the biological activities of stress, upregulates mdr1 gene expression in MCF-7 breast cancer cells via alpha(2)-adrenergic receptors in a dose-dependent manner. Mdr1 upregulation can be specifically inhibited by pretreatment with mdr1-siRNA. Consequently, adrenergic stimulation enhances the pump function of P-glycoprotein and confers resistance of MCF-7 cells to paclitaxel. In vivo, restraint stress increases mdr1 gene expression in the MCF-7 cancers that are inoculated subcutaneously into the SCID mice and provokes resistance to doxorubicin in the implanted tumors. The effect can be blocked by injection of yohimbine, an alpha(2)-adrenergic inhibitor, but not by metyrapone, a corticosterone synthesis blocker. Therefore, we conclude that breast cancers may develop resistance against chemotherapeutic drugs under psychological distress by over-expressing mdr1 via adrenergic stimulation.