A rapid and systematic review of the clinical effectiveness and cost-effectiveness of topotecan for ovarian cancer

Synchronizing the release rates of topotecan and paclitaxel from a self-eroding crosslinked chitosan - PLGA platform

This study is a continuation of a previous study in which two model drugs, sodium salicylate (highly water-soluble) and indomethacin (low water-soluble) were loaded into an erodible hydrogel, made of ionically crosslinked chitosan (x-Ct). The erosion rate of the x-Ct matrix was controlled by its immersion in calcium chloride solutions (de-crosslinker) of different concentrations, leading to synchronization of the release rates of the two drugs over 2 h. In the present study, a modified platform was developed in order to (a) synchronize the release rates of the two cytotoxic drugs, topotecan (TT, highly water soluble) and paclitaxel (PTX, poorly water soluble); (b) prolong the erosion duration and the derived concomitant release of the two drugs to several days. TT was loaded into a PLGA sphere, which was co-loaded with calcium chloride (CaCl₂). The sphere was then placed in an aqueous solution of chitosan (Ct) in which PTX was dispersed. A PLGA core-containing hydrogel was then produced by ionically crosslinking the Ct. The formulation screening section of the study includes a statistically designed Fractional Factorial experiment. It was comprised of the following five experimental factors: (a) the type of Ct and (b) its relative amount in the formulation, (c) the type of ionic crosslinker (citric acid or oxalic acid), (d) the concentration of the ionic crosslinker and (e) the co-loaded amounts of CaCl₂ (the constitutional de-crosslinking agent). The difference factor, f1, and the similarity factor, f2, of the TT and PTX release profiles into water, were used as the experimental responses. The computerized prediction models were employed to assess the collective effects of the pre-determined experimental factors on the difference factor, f1, and the similarity factor, f2 (the response factors), by employing a fractional factorial design and multifactorial analysis, without the need to account for the exact mechanisms of the release processes involved. The final composite platform was capable of releasing TT and PTX, at similar (concomitant) rates, over a period of 7 days, a finding which suggests that the novel polymeric platform may serve as a multi-drug implant. An attractive medical application for such a device would be post-operative local treatment that could benefit from localized combination chemotherapy after the removal of malignant tissues, in the surgical treatment of breast cancer, ovarian cancer, glioma and peritoneal carcinomatosis.

Controlling the release rate of topotecan from PLGA spheres and increasing its cytotoxicity towards glioblastoma cells by co-loading with calcium chloride

It has been suggested that local administration of topotecan (TT) could increase its efficacy in the treatment of glioblastoma. In this context, a PLGA implant model in the form of spheres with a porous core and stiff surface, loaded with TT and CaCl₂ was developed. An array of formulations differing from each other by the type of PLGA used, the integrity of the surface, the concentrations of TT and CaCl₂ added during the preparation, and the volume of water in the PLGA mix, was prepared, screened and explored by computerized multifactorial analysis. This analysis enabled the simultaneous identification of the most influential experimental factors on the experimental responses, which were pre-determined as the efficiency of TT loading and the TT % cumulative release at 14 days. The multifactorial analysis also revealed how the interactions among the experimental factors affect the performance of the various formulations. Thus, TT concentration and its factorial interaction with the concentration of CaCl₂ added during the spheres' preparation were identified as most prominent on the loading efficiency, while the surface integrity (intact or punctured) and CaCl₂ amount in the spheres were identified as most prominent on the TT % cumulative release from the spheres. TT was found to be cytotoxic towards glioblastoma U87 MG cells, an activity which was enhanced, synergistically, in the presence of CaCl₂ (the relative viability was reduced from 36 to 28% with combination indices of 1.0, 0.37, 0.13 and 0.06 for EC₅₀, EC₇₅, EC₉₀ and EC₉₅, respectively). Interestingly, dividing the TT dose into 3 equal portions, replenished daily to the incubation medium, increased TT cytotoxicity. The relative viability was then reduced from 35 to 7% and in the presence of CaCl₂ - from 28 to 1.9%, suggesting that a local, slow input of TT could be effective in the treatment of glioblastoma by an adjacent TT implant. The increased effect of CaCl₂ on cytotoxicity was also observed when it was co-loaded into the TT spheres. In that case, the cells' viability was reduced from 72 to 27%. It is suggested that the PLGA spheres could be used for tunable local delivery of TT in post-resection adjuvant therapy of glioblastoma.

The ovarian cancer oncobiome

Humans and other mammals are colonized by microbial agents across the kingdom which can represent a unique microbiome pattern. Dysbiosis of the microbiome has been associated with pathology including cancer. We have identified a microbiome signature unique to ovarian cancers, one of the most lethal malignancies of the female reproductive system, primarily because of its asymptomatic nature during the early stages in development. We screened ovarian cancer samples along with matched, and non-matched control samples using our pan-pathogen array (PathoChip), combined with capture-next generation sequencing. The results show a distinct group of viral, bacterial, fungal and parasitic signatures of high significance in ovarian cases. Further analysis shows specific viral integration sites within the host genome of tumor samples, which may contribute to the carcinogenic process. The ovarian cancer microbiome signature provides insights for the development of targeted therapeutics against ovarian cancers.

What is a rapid review? A methodological exploration of rapid reviews in Health Technology Assessments

AIM

Commissioners of Health Technology Assessments require timely reviews to attain efficacious decisions on healthcare and treatments. In recent years, there has been an emergence of 'rapid reviews' within Health Technology Assessments; however, there is no known published guidance or agreed methodology within recognised systematic review or Health Technology Assessment guidelines. In order to answer the research question 'What is a rapid review and is methodology consistent in rapid reviews of Health Technology Assessments?', a study was undertaken in a sample of rapid review Health Technology Assessments from the Health Technology Assessment database within the Cochrane Library and other specialised Health Technology Assessment databases to investigate similarities and/or differences in rapid review methodology utilised.

METHOD

In a targeted search to obtain a manageable sample of rapid reviews, the Health Technology Assessment database of The Cochrane Library and six international Health Technology Assessment databases were searched to locate rapid review Health Technology Assessments from 2000 onwards. Each rapid review was examined to investigate the individual methodology used for searching, inclusion screening, quality assessment, data extraction and synthesis. Methods of each rapid review were compared to investigate differences and/or similarities in methodologies used, in comparison with recognised methods for systematic reviews.

RESULTS

Forty-six full rapid reviews and three extractable summaries of rapid reviews were included. There was a wide diversity of methodology, with some reviews utilising well-established systematic review methods, but many others diversifying in one or more areas, that is searching, inclusion screening, quality assessment, data extraction, synthesis methods, report structure and number of reviewers. There was a significant positive correlation between the number of recommended review methodologies utilised and length of time taken in months.

CONCLUSIONS

Despite the number of rapid reviews published within Health Technology Assessments over recent years, there is no agreed and tested methodology and it is unclear how rapid reviews differ from systematic reviews. In a sample of Health Technology Assessment rapid reviews from 2000 to 2011, there was a wide diversity of methodology utilised in all aspects of rapid reviews. There is scope for wider research in this area to investigate the diversity of methods in more depth during each stage of the rapid review process, so that eventually recommendations could be made for clear and systematic methods for rapid reviews, thus facilitating equity and credibility of this type of important review methodology.

Subunit-dependent inhibition and potentiation of 5-HT3 receptor by the anticancer drug, topotecan

The 5-hydroxytryptamine (serotonin, 5-HT) type 3 (5-HT3) receptor belongs to the superfamily of Cys-loop ligand-gated ion channels, and can be either homopentameric (5-HT3A) or heteropentameric (5-HT3AB) receptor. Several modulators are known, which either inhibit or potentiate this channel, but few have any appreciable selectivity between the two subtypes or can modulate one receptor differently to the other. In this study, we show that the anticancer drug, topotecan, bidirectionally modulates the 5-HT3 receptor using a two-electrode voltage clamp technique. Topotecan inhibited 5-HT-gated current through homomeric 5-HT3A receptors. Interestingly, however, additional expression of the 5-HT3B subunit changed the response to topotecan dramatically from an inhibitory to a potentiatory one. This effect was dependent on the level of 5-HT3B subunit expression. Moreover, the effect was reduced in the receptors containing the 5-HT3B(Y129S) polymorphic variant. These finding could explain individual differences in the sensitivity to topotecan-induced nausea and vomiting.

Structural characterization of an anhydrous polymorph of paclitaxel by solid-state NMR

The three-dimensional structure of a unique polymorph of the anticancer drug paclitaxel (Taxol) is established using solid state NMR (SSNMR) tensor ((13)C & (15)N) and heteronuclear correlation ((1)H-(13)C) data. The polymorph has two molecules per asymmetric unit (Z' = 2) and is thus the first conformational characterization with Z' > 1 established solely by SSNMR. Experimental data are correlated with structure through a series of computational models that extensively sample all conformations. For each computational model, corresponding tensor values are computed to supply comparisons with experimental information which, in turn, establishes paclitaxel's structure. Heteronuclear correlation data at thirteen key positions provide shift assignments to the asymmetric unit for each comparison. The two distinct molecules of the asymmetric unit possess nearly identical baccatin III moieties with matching conformations of the C10 acetyl moiety and, specifically, the torsion angle formed by C30-O-C10-C9. Additionally, both are found to exhibit an extended conformation of the phenylisoserine sidechain at C13 with notable differences in the dihedral angles centered around the rotation axes of O-C13, C2'-C1' and C3'-C2'.

Cost-effectiveness of omalizumab in patients with severe persistent allergic asthma

BACKGROUND

The health, economic and societal burden of asthma is considerable, and is greatest in patients with severe asthma, particularly when inadequately controlled. Real-life studies that assess the effectiveness of treatment are of particular interest.

METHODS

We determined the incremental cost-effectiveness ratio (ICER) of adding omalizumab to standard therapy using data from the real-life 1-year randomized open-label study (ETOPA) and using Canada as a reference country. Only patients receiving high-dose ICS plus LABA were included in the analysis, reflecting the EU label for omalizumab. Costs and quality-adjusted life years (QALYs) gained were used to calculate the ICER for omalizumab (cost/QALY). Probabilistic sensitivity analysis was performed to determine the 95% confidence interval and one-sided sensitivity analyses were performed.

RESULTS

The base case lifetime analysis of standard therapy vs standard therapy plus add-on omalizumab for the first 5 years, gave an ICER of 31,209 Euro. Probabilistic sensitivity analysis indicated that the 95% confidence interval around the ICER was 27,739-40,840 Euro. The ICER range for one-way sensitivity analyses was 23,762 Euro without discounting to 66,443 Euro without inclusion of asthma-related mortality.

CONCLUSIONS

This study demonstrates that add-on omalizumab therapy is cost-effective in patients with severe persistent allergic asthma.

Case study of the comparison of data from conference abstracts and full-text articles in health technology assessment of rapidly evolving technologies: does it make a difference?

OBJECTIVES

The aim of this study was to examine (i) the consistency of reporting research findings presented in conference abstracts and presentations and subsequent full publications, (ii) the ability to judge methodological quality of trials from conference abstracts and presentations, and (iii) the effect of inclusion or exclusion of data from these sources on the pooled effect estimates in a meta-analysis.

METHODS

This report is a case study of a selected health technology assessment review (TAR) of a rapidly evolving technology that had identified and included a meta-analysis of trial data from conference abstracts and presentations.

RESULTS

The overall quality of reporting in abstracts and presentations was poor, especially in abstracts. There was incomplete or inconsistent reporting of data in the abstract/presentations. Most often inconsistencies were between conference slide presentations and data reported in published full-text articles. Sensitivity analyses indicated that using data only from published papers would not have altered the direction of any of the results when compared with those using published and abstract data. However, the statistical significance of three of ten results would have changed. If conference abstracts and presentations were excluded from the early analysis, the direction of effect and statistical significance would have changed in one result. The overall conclusions of the original analysis would not have been altered.

CONCLUSIONS

There are inconsistencies in data presented as conference abstracts/presentations and those reported in subsequent published reports. These inconsistencies could impact the final assessment results. Data discrepancies identified across sources included in TARs should be highlighted and their impact assessed and discussed. Sensitivity analyses should be carried out with and without abstract/presentation data included in the analysis. Incomplete reporting in conference abstracts and presentations limits the ability of reviewers to assess confidently the methodological quality of trials.

Incorporating direct and indirect evidence using bayesian methods: an applied case study in ovarian cancer

OBJECTIVE

To demonstrate the application of a Bayesian mixed treatment comparison (MTC) model to synthesize data from clinical trials to inform decisions based on all relevant evidence.

METHODS

The value of an MTC model is demonstrated using a probabilistic decision-analytic model developed to assess the cost-effectiveness of second-line chemotherapy in ovarian cancer. Three clinical trials were found that each made a different pair-wise comparison of three treatments of interest in the overall patient population. As no common comparator existed between the three trials, an MTC model was used to assess the combined weight of evidence on survival from all three trials simultaneously. This analysis was compared to an alternative approach that combined two of the trials to make the same comparison of all three treatments using a common comparator, and an informal approach that did not synthesize the available evidence.

RESULTS

By including all three trials using an MTC model, the credible intervals around estimated overall survival were reduced compared with making the same comparison using only two trials and a common comparator. Nevertheless, the survival estimates from the MTC model result in greater uncertainty around the optimal treatment strategy at a cost-effectiveness threshold of 30,000 pounds per quality-adjusted life-year.

CONCLUSIONS

MTC models can be used to combine more data than would typically be included in a traditional meta-analysis that relies on a common comparator. They can formally quantify the combined uncertainty from all available evidence, and can be conducted using the same analytical approaches as standard meta-analyses.

Palliative care treatment patterns and associated costs of healthcare resource use for specific advanced cancer patients in the UK

The purpose of this paper is to identify the treatment patterns and corresponding costs of healthcare resource use associated with palliative care for different types of advanced cancer patients, from the time they started strong opioid treatment until death. This was a modelling study performed from the perspective of the UK's National Health Service (NHS). A data set was created comprising 547 patients in the DIN-Link database who had a Read code for malignant neoplasms with a specific tumour-type diagnosis and who received their first strong opioid between 1 January 1998 and 30 September 2000 and died during that period. Palliative care-related resource utilization data were obtained from the DIN-Link database. Unit costs at 2000/2001 prices were applied to the resource use estimates to determine the mean cost of palliative care from the start of treatment until death. There were significant differences in age between patients with different cancer types and in patients' survival from diagnosis, time to the start of palliative care and duration of palliative care. The mean duration from cancer diagnosis to the start of strong opioid treatment ranged from 0.7 to 5.4 years in patients with lung and breast cancer respectively. Moreover, the length of palliative care ranged from 180 to 372 days in patients with these cancer types respectively. There were also statistically significant differences in resource use between patients with different cancer types, but this reflected, in part, the varying durations of palliative care. Nevertheless, there were also differences in the monthly number of primary care visits reflecting the different number of monthly prescriptions. There was no apparent relationship between the length and corresponding cost of palliative care which ranged from 1816 pounds sterling for colon cancer to 4789 pounds sterling for ovarian cancer. Additionally, on average, only a third of all patients also received 4-hourly morphine as part of their initial strong opioid treatment. The total cost of palliative care varied between cancer type and reflects, at least in part, the distinct clinical features associated with different tumours and the varying lengths of survival following the start of strong opioid treatment. Nevertheless, no apparent relationship was found between length of palliative care and corresponding costs. This analysis provides data on palliative care resource use for a variety of cancers and could provide useful input when planning local healthcare strategies and building service commissioning models.

Assessing economics of treatments for gynecological cancer where clinical effectiveness meets value for money

During the last 10 years, the management of gynecological cancer has been undergoing a great deal of change. This is due to a drive to reduce ineffective treatment and associated morbidity while at the same time maximizing the benefits of currently available treatment. The foundation for this approach has been high-quality clinical trials which have been performed in increasing numbers. These trials can provide strong evidence that treatments are equivalent or that a new drug adds superiority to previous treatment. The access that women have to the most effective forms of treatment often depends on the availability of healthcare resources and their affordability within the healthcare system. Healthcare decision makers increasingly require not just clinical effectiveness of treatments but also cost-effectiveness to be demonstrated. While health economic methods have been applied to many forms of cancer treatment and screening, there have been very few rigorous economic studies performed in gynecological cancer. This article discusses how economic analysis can be incorporated into clinical trials and how it can provide the sort of value for money determination that payers of healthcare are now requiring. Economic analysis may add a little to the cost of trials, but in the end, it may increase access to treatment by convincing decision makers of cost-effectiveness.

Cross-national comparison of technology assessment processes

Objectives:To compare methods and results among four health technology assessment organizations in different countries.

Methods:All assessment reports published between 1999 and 2001 by VATAP (United States), NICE (United Kingdom), CCOHTA (Canada), and AETS (Spain), were reviewed. Detailed information about the organization, the technology assessed, the methods used, and the recommendations made were collected. A descriptive analysis of the variables, as well as comparisons of means and proportions, was performed.

Results:Sixty-one reports assessing seventy-six technologies were published: nine (11.8 percent) by VATAP, thirty-nine (51.3 percent) by NICE, twenty (26.3 percent) by CCOHTA, and eight (10.5 percent) by AETS. A total of 64.5 percent of the technologies assessed were related to a high prevalence disease in the corresponding country. Most of the assessments addressed treatments (73.7 percent) and were mostly drugs (56.6 percent) and devices (23.7 percent). Most organizations used reviews of effectiveness and economic evaluations (64.5 percent), systematic reviews (21.1 percent), and original economic evaluations (36.7 percent). In 38.1 percent, the technology was recommended; the rest of the cases had no formal recommendations.

Conclusions:Critical issues for future technology assessment efforts are making assessment processes more consistent, transparent, and evidence-based; formalizing the inclusion of economic and ethical considerations; and making more explicit the prioritization process for selecting technologies for assessment and reassessment.

Topotecan is an active agent in the first-line treatment of metastatic or recurrent endometrial carcinoma: Eastern Cooperative Oncology Group Study E3E93

PURPOSE

To determine the clinical activity and the toxicity profile of the topoisomerase-I inhibitor, topotecan, in women with recurrent or advanced endometrial carcinoma.

PATIENTS AND METHODS

A prospective, phase II clinical trial was initiated by the Eastern Cooperative Oncology Group (ECOG). Patients had histologically confirmed advanced or recurrent endometrial carcinoma, measurable disease, no prior cytotoxic therapy, an ECOG performance status of 0 to 2, and evidence of disease progression while on progestins or after radiation therapy. Topotecan was administered at 1.5 mg/m(2) (or 1.2 mg/m(2) for patients with prior pelvic radiation) intravenously daily for 5 days every 3 weeks.

RESULTS

A total of 44 patients were enrolled; 42 were eligible. The study was suspended because of unexpected toxicities, primarily sepsis and bleeding. After toxicity review, the study was reopened using lower doses of topotecan (1.0 mg/m(2) or 0.8 mg/m(2) for patients with prior radiation therapy). In addition, prophylactic use of growth factors was allowed after the first cycle, and patients with performance status of 2 were excluded. The major toxicities were hematologic and gastrointestinal. Among the 40 assessable patients, there were three (7.5%) complete responders and five partial responders (12.5%), for an overall response rate of 20%. The median duration of response was 8.0 months and of overall survival was 6.5 months.

CONCLUSION

Topotecan is an active agent for the treatment of advanced endometrial carcinoma. At the doses and schedules initially used, toxicities were unacceptable; however, at the modified doses, toxicities were acceptable and clinical activity was preserved.

Management of treatment-related toxicity in advanced ovarian cancer

Recognition of recurrent ovarian cancer as a disease with significant secondary responses and remissions has led to an increase in the need for oncologists to plan for the long-term therapy of patients. However, many of the currently available front-line and salvage agents used in advanced ovarian cancer are associated with cumulative and/or irreversible toxicities that pose challenges in long-term planning. The irreversible effects associated with some of these therapies may render patients less tolerant to subsequent treatments and lead to a cycle of diminishing treatment options with each remission and disease relapse. Additionally, the potential for patients to experience cumulative toxicity must be carefully weighed against the goals of prolonging the disease-free interval and improving patient quality of life. A number of agents are available in the treatment armamentarium (platinum, paclitaxel, gemcitabine, etoposide, liposomal doxorubicin, and topotecan), many, but not all of which are associated with cumulative toxicity. For instance, cumulative neurotoxicity associated with cisplatin as first-line therapy may diminish the option for retreatment with platinum at first relapse. In contrast, the main toxicity associated with topotecan is noncumulative, manageable myelosuppression. In this review, the major toxicities associated with the predominant chemotherapy agents used in advanced ovarian cancer are discussed along with selected management approaches in the context of long-term treatment planning and sequencing.