Desvenlafaxina para el tratamiento de la depresión moderada a severa en pacientes con cáncer de mama usuarias de Tamoxifeno / Desvenlafaxine for the treatment of moderate to severe depression in patients with breast cancer who use Tamoxifen

INTRODUCCIÓN: En Perú, la prevalencia de la depresión en mujeres con cáncer de mama (estadío I o II) ha sido reportada en un rango de 21.9% a 25.6%, y por niveles en un 16.9% para síntomas leves, 6.3% moderado y 2.4% severo. El tratamiento antidepresivo usado en primera línea, como los Inhibidores selectivos de la recaptación de serotonina, inhiben la CYP2D6 en diferentes grados. Los nuevos agentes antidepresivos han mostrado un mejor perfil en su prescripción conjunta. Algunos recomiendan evitar fármacos como la paroxetina y fluoxetina para el tratamiento conjunto. La literatura sugiere que los antidepresivos más seguros son la Venlafaxina, Desvenlafaxina y Mirtazapina. CUADRO CLÍNICO: El tratamiento de la depresión, preferentemente moderada a severa, de primera línea es el uso de IRSS, así como nuevos agentes que han mostrado menor efecto adverso y mayor eficacia. En mujeres, el uso del Tamoxifeno puede inducir síntomas propios de la menopausia y se ha reportado eficacia de antidepresivos como la Venlafaxina para el tratamiento de los sofocos en conjunto con el Tamoxifeno. La coprescripción de la Desvenlafaxina y el Tamoxifeno se ha sugerido por su baja concentración en el plasma, aunque la evidencia no sea suficiente. TECNOLOGÍA SANITARIA: La Desvenlafaxina es el principal metabolito activo de la Venlafaxina, es un antidepresivo de la clase de los inhibidores de la recaptación de serotonina y norepinefrina. La desvenlafaxina inhibe la recaptación de neurotransmisores en los transportadores de serotonina, noradrenalina y dopamina. La Desvenlafaxina inhibe los transportadores de serotonina y con una afinidad 10 veces superior a la de los transportadores de noradrenalina y los transportadores de dopamina con la menor afinidad. Se puede utilizar para el tratamiento de depresión mayor en adultos y síntomas como el sofoco en mujeres pre y pos menopáusicas. Está formulado como un comprimido de liberación prolongada. OBJETIVO: Evaluar la eficacia y seguridad, así como documentos relacionados a la decisión de cobertura de la Desvenlafaxina en pacientes con cáncer de mama comparado a otros antidepresivos. METODOLOGÍA: Se realizó una búsqueda sistemática en las bases de datos bibliográficas: MEDLINE (PubMed), LILACS, Cochrane Library, así como en buscadores genéricos de Internet incluyendo Google Scholar. Así también, se hizo una búsqueda en agencias que realizan evaluación de tecnologías sanitarias (ETS) y guías de práctica clínica (GPC). RESULTADOS: Se identificó un ensayo clínico abierto y dos GPC. No se encontraron ETS o Evaluaciones económicas en la región. CONCLUSIONES: La evidencia en relación a la interacción de la Desvenlafaxina y el uso del Tamoxifeno concomitante es insuficiente. Un único estudio de tipo farmacocinético, con el uso concomitante, no alteró la concentración minima, reciente y máxima de la Desvenlafaxina. Las guías de práctica clínica identificadas, en general, recomiendan el uso (o coprescripción) de la Desvenlafaxina en mujeres con cáncer de mama usuarias de Tamoxifeno por su nivel de eficacia semejante a otros Inhibidores de Recaptación de Noradrenalina y la baja concentración en plasma del endoxifeno. El nivel de concentración mínima reportada se sugiere como un parámetro, farmacocinético y farmacodinámico, a favor al momento de tomar la decisión de la elección del fármaco y su posología. Las guías de práctica clínica identificadas, en general, recomiendan el uso (o coprescripción) de la Desvenlafaxina en mujeres con cáncer de mama usuarias de Tamoxifeno por su nivel de eficacia semejante a otros Inhibidores de recaptación de Noradrenalina y la baja concentración en plasma del endoxifeno. Cuando sea posible, se recomienda el uso de Citalopram, Escitalopram, Venlafaxina y Desvenlafaxina, dosis bajas de Sertralina o Mirtazapina como antidepresivos de primera línea. Finalmente y de modo general, se recomienda no usar antidepresivos de forma rutinaria para el tratamiento de depresión leve o subclínica, más bien considerar el nivel de severidad, principalmente en el tratamiento de la depresión severa.

Formulation, characterization, and cellular toxicity assessment of tamoxifen-loaded silk fibroin nanoparticles in breast cancer.

Silk fibroin (SF) is a natural polymeric biomaterial that is widely adopted for the preparation of drug delivery systems. Herein, we aimed to fabricate and characterize SF nanoparticles loaded with the selective estrogen receptor modulator; tamoxifen citrate (TC-SF-NPs) and to assess their in vitro efficacy against breast cancer cell lines (MCF-7 and MDA-MB-231). TC-loaded SF-NPs were characterized for particle size, morphology, entrapment efficiency, and release profile. In addition, we examined the in vitro cytotoxicity of TC-SF-NPs against human breast cancer cell lines and evaluated the anticancer potential of TC-SF-NPs through apoptosis assay and cell cycle analysis. Drug-loaded SF-NPs showed an average particle size of 186.1 ± 5.9 nm and entrapment efficiency of 79.08%. Scanning electron microscopy (SEM) showed the nanoparticles had a spherical morphology with smooth surface. Tamoxifen release from SF-NPs exhibited a biphasic release profile with an initial burst release within the first 6 h and sustained release for 48 h. TC-SF-NPs exerted a dose-dependent cytotoxic effect against breast cancer cell lines. In addition, flow cytometry analysis revealed that cells accumulate in G0/G1 phase, with a concomitant reduction of S- and G2-M-phase cells upon treatment with TC-SF-NPs. Consequently, the potent anticancer activities of TC-SF-NPs against breast cancer cells were mainly attributed to the induction of apoptosis and cell cycle arrest. Our results indicate that SF nanoparticles may represent an attractive nontoxic nanocarrier for the delivery of anticancer drugs.

Antimicrobial, Antitumor and Side Effects Assessment of a Newly Synthesized Tamoxifen Analog.

BACKGROUND: Tamoxifen citrate is a very prevalent drug marketed under several trade names like Apo-Tamox, Nolvadex, Tamec, Tamizam, and Tamoplex. This molecule is approved by the FDA for breast cancer treatment. Some studies have shown that tamoxifen has anti-tuberculosis and antiparasitic activities. Like any drug, tamoxifen possesses side effects, more or less dangerous. AIMS: Basically, this work is a comparative study that aims to: primarily compare the antimicrobial and antitumor activities of tamoxifen and a newly synthesized tamoxifen analog; and to determine the molecule with lesser side effects. METHODS: Three groups of mice were injected with tamoxifen citrate and compound 2(1,1-bis[4-(3- dimethylaminopropoxy)phenyl]-2-phenyl-but-1-ene dihydrochloride) at doses corresponding to C1 (1/10), C2 (1/50), and C3 (1/100) to compound 2 lethal dose (LD50 = 75 mg/kg) administered to adult mice. A group of noninjected mice served as a study control. RESULTS: Experimental results suggest that compound 2 has better antitumor and antimicrobial activity than tamoxifen citrate besides its lower toxicity effects. CONCLUSION: The results obtained from the present study confirmed the antitumor and antimicrobial effect of tamoxifen citrate and its hematological side effects. Compound 2 seems to be more effective than tamoxifen citrate for antitumor and antimicrobial treatment while having less hematological side effects and less disruption of the blood biochemical parameters. These findings encourage us to perform further studies on compound 2 and test it for other therapeutic uses for which tamoxifen was found effective.

Pharmacological, Mechanistic, and Pharmacokinetic Assessment of Novel Melatonin-Tamoxifen Drug Conjugates as Breast Cancer Drugs.

Tamoxifen is used to prevent and treat estrogen receptor-positive (ER+) breast cancer (BC); however, its chronic use can increase uterine cancer risk and induce tamoxifen resistance. Novel melatonin-tamoxifen drug conjugates may be promising to treat BC and may help offset the adverse effects of tamoxifen usage alone due to the presence of melatonin. We synthesized and screened five drug conjugates (C2, C4, C5, C9, and C15 linked) for their effects on BC cell (MCF-7, tamoxifen-resistant MCF-7, mouse mammary carcinoma, MDA-MB-231, and BT-549) viability, migration, and binding affinity to melatonin receptor 1 (MT1R) and estrogen receptor 1 (ESR1). C4 and C5 demonstrated the most favorable pharmacological characteristics with respect to binding profiles (affinity for ESR1 and MT1R) and their potency/efficacy to inhibit BC cell viability and migration in four phenotypically diverse invasive ductal BC cell lines. C4 and C5 were further assessed for their actions against tamoxifen-resistant MCF-7 cells and a patient-derived xenograft triple-negative BC cell line (TU-BcX-4IC) and for their mechanisms of action using selective mitogen-activated protein kinase kinase MEK1/2, MEK5, and phosphoinositide 3-kinase (PI3K) inhibitors. C4 and C5 inhibited tamoxifen-resistant MCF-7 cells with equal potency (IC50 = 4-8 µM) and efficacy (∼90% inhibition of viability and migration) but demonstrated increased potency (IC50 = 80-211 µM) and efficacy (∼140% inhibition) to inhibit migration versus cell viability (IC50 = 181-304 mM; efficacy ∼80% inhibition) in TU-BcX-4IC cells. Unique pharmacokinetic profiles were observed, with C4 having greater bioavailability than C5. Further assessment of C4 and C5 demonstrates that they create novel pharmacophores within each BC cell that is context specific and involves MEK1/2/pERK1/2, MEK5/pERK5, PI3K, and nuclear factor κB. These melatonin-tamoxifen drug conjugates show promise as novel anticancer drugs and further preclinical and clinical evaluation is warranted.

DNA Adduct Assessment During Antihormonal Treatment of Perianal Gland Tumors With Tamoxifen in Male Dogs.

BACKGROUND/AIM: Determination of DNA adduct count was performed in mononuclear cells during antihormonal treatment of perianal gland tumors. MATERIALS AND METHODS: Eight- to fifteen-year-old dogs with carcinoma (CAR Group; N=5), epithelioma (EPI Group; N=16) or adenoma (ADE Group; N=24) were used. The control group suffered from perineal hernia or rectal diverticulum (CTR Group; N=25). Blood was collected at baseline, and at one and six months after the beginning of the anti-hormonal treatment with tamoxifen (1 mg/kg of body weight). DNA adduct count was determined using autoradiography. RESULTS: At baseline, DNA adduct count reached the highest value in the CTR Group, and the lowest in the EPI Group (p<0.05). Six-month-long therapy with tamoxifen resulted in a significant increase in the DNA adduct count by 78.7%, 221.5% and 198.3% in the ADE, EPI and CAR groups, respectively (p<0.05). CONCLUSION: Increased DNA adduct formation after long-term administration of tamoxifen shows its genotoxicity.

N-terminal transactivation function, AF-1, of estrogen receptor alpha controls obesity through enhancement of energy expenditure.

OBJECTIVE: Studies using the estrogen receptor alpha (ERα) knock-out (αERKO) mice have demonstrated that ERα plays a crucial role in various estrogen-mediated metabolic regulations. ERα is a ligand dependent transcription regulator and its activity is regulated by estrogenic compounds. ERα consists of two transcriptional activation domains, AF-1 and AF-2. The activities of these domains are regulated through different mechanisms; however, the specific physiological role in metabolic regulation by these domains is still unclear. METHODS: We utilized an ERα AF-2 mutant knock-in mouse (AF2ERKI) to evaluate the physiological functionality of ERα transactivation domains. Due to the estrogen insensitive AF-2 mutation, the phenotypes of AF2ERKI mice are seemingly identical to the global αERKO including obesity in the females. Distinct from the αERKO, the AF-1 function of AF2ERKI mice can be activated by tamoxifen (Tam). Ovariectomized (OVX) AF2ERKI and WT females were treated with Tam and fed a high-fat diet (HFD) for 10 weeks. Additionally, indirect calorimetric analysis was performed using metabolic chambers with food intake and locomotor activity recorded for Tam-treated AF2ERKI and αERKO females. RESULTS: Obesity in HFD-fed AF2ERKI females was prevented by Tam treatment; particularly, inguinal fat accumulation was strongly blocked by Tam treatment. Alterations in fat metabolism genes, however, were not found in either inguinal fat nor visceral fat to be Tam-regulated, even though fat accumulation was strongly reduced by Tam treatment. Indirect calorimetric analysis revealed that without alteration of food intake and locomotor activity Tam treatment increased energy expenditure in AF2ERKI but not αERKO females. CONCLUSIONS: These results suggest that the activation of ERα AF-1 prevents fat accumulation. The prevention of obesity through AF-1 is mediated by induction of energy expenditure rather than ERα AF-1 functionality of lipid metabolism gene regulation in fat tissues.

Co-clinical assessment identifies patterns of BRAF inhibitor resistance in melanoma.

Multiple mechanisms have been described that confer BRAF inhibitor resistance to melanomas, yet the basis of this resistance remains undefined in a sizable portion of patient samples. Here, we characterized samples from a set of patients with melanoma that included individuals at baseline diagnosis, on BRAF inhibitor treatment, and with resistant tumors at both the protein and RNA levels. Using RNA and DNA sequencing, we identified known resistance-conferring mutations in 50% (6 of 12) of the resistant samples. In parallel, targeted proteomic analysis by protein array categorized the resistant samples into 3 stable groups, 2 of which were characterized by reactivation of MAPK signaling to different levels and 1 that was MAPK independent. The molecular relevance of these classifications identified in patients was supported by both mutation data and the similarity of resistance patterns that emerged during a co-clinical trial in a genetically engineered mouse (GEM) model of melanoma that recapitulates the development of BRAF inhibitor resistance. Additionally, we defined candidate biomarkers in pre- and early-treatment patient samples that have potential for predicting clinical responses. On the basis of these observations, we suggest that BRAF inhibitor-resistant melanomas can be actionably classified using protein expression patterns, even without identification of the underlying genetic alteration.

Bayesian approach for flexible modeling of semicompeting risks data.

Semicompeting risks data arise when two types of events, non-terminal and terminal, are observed. When the terminal event occurs first, it censors the non-terminal event, but not vice versa. To account for possible dependent censoring of the non-terminal event by the terminal event and to improve prediction of the terminal event using the non-terminal event information, it is crucial to model their association properly. Motivated by a breast cancer clinical trial data analysis, we extend the well-known illness-death models to allow flexible random effects to capture heterogeneous association structures in the data. Our extension also represents a generalization of the popular shared frailty models that usually assume that the non-terminal event does not affect the hazards of the terminal event beyond a frailty term. We propose a unified Bayesian modeling approach that can utilize existing software packages for both model fitting and individual-specific event prediction. The approach is demonstrated via both simulation studies and a breast cancer data set analysis.

A hidden Markov model to identify combinatorial epigenetic regulation patterns for estrogen receptor α target genes.

MOTIVATION: Many studies have shown that epigenetic changes, such as altered DNA methylation and histone modifications, are linked to estrogen receptor α (ERα)-positive tumors and disease prognoses. Several recent studies have applied high-throughput technologies such as ChIP-seq and MBD-seq to interrogate the altered architectures of ERα regulation in tamoxifen (Tam)-resistant breast cancer cells. However, the details of combinatorial epigenetic regulation of ERα target genes in breast cancers with acquired Tam resistance have not yet been fully examined. RESULTS: We developed a computational approach to identify and analyze epigenetic patterns associated with Tam resistance in the MCF7-T cell line as opposed to the Tam-sensitive MCF7 cell line, with the goal of understanding the underlying mechanisms of epigenetic regulatory influence on resistance to Tam treatment in breast cancer. In this study, we used ChIP-seq of ERα, RNA polymerase II, three histone modifications and MBD-seq data of DNA methylation in MCF7 and MCF7-T cells to train hidden Markov models (HMMs). We applied the Bayesian information criterion to determine that a 20-state HMM was best, which was reduced to a 14-state HMM with a Bayesian information criterion score of 1.21291 × 10(7). We further identified four classes of biologically meaningful states in this breast cancer cell model system, and a set of ERα combinatorial epigenetic regulated target genes. The correlated gene expression level and gene ontology analyses showed that different gene ontology terms were enriched with Tam-resistant versus sensitive breast cancer cells. Our study illustrates the applicability of HMM-based analysis of genome-wide high-throughput genomic data to study epigenetic influences on E2/ERα regulation in breast cancer.

Genetic Cre-loxP assessment of epicardial cell fate using Wt1-driven Cre alleles.

RATIONALE: Wt1-Cre-based tools are important reagents for studying epicardial cell fate and gene function. OBJECTIVE: To better describe the properties of Wt1-Cre-based tools to enhance their use in Cre-loxP-based experiments. METHODS AND RESULTS: In contrast to recently reported results, we show that constitutive Wt1(GFPCre) in combination with certain Cre-activated reporters can be used to trace (pro) epicardial cell fate. Wt1(CreERT2) can be efficiently induced by tamoxifen administration. We show substantial labeling of coronary endothelial cells when induction is performed at late but not early stages of heart development. CONCLUSIONS: Wt1-based Cre alleles are useful tools for genetic lineage tracing of epicardial cells and mesothelium of other organs. Using these tools with proper understanding of their properties and limitations enables genetic labeling of epicardial cells and their derivatives.

Assessment of micronucleus frequency in the peripheral blood of female rats in persistent estrus treated with selective estrogen receptor modulators.

The aim of this study was to evaluate micronucleus (MN) frequency in polychromatic erythrocytes (PCE) of female rats in persistent estrus (a model developed to mimic polycystic ovary syndrome) treated with selective estrogen receptor modulators (SERMs, tamoxifen, and raloxifene). Forty female Wistar-Hannover rats were divided into four groups of 10 animals each: Group I (normally cycling rats) and Group II (persistent estrus) both received only vehicle, while Group III (persistent estrus) was treated with tamoxifen (250 µg/animal/day) and Group IV (persistent estrus) was treated with raloxifene (750 µg/animal/day). Tamoxifen and raloxifene were given by oral gavage beginning on postnatal day 90 and continuing for 30 consecutive days. Peripheral blood samples were collected from tails 1 day following the last exposure. Blood smears were made on glass slides and stained with 10% Giemsa solution. ANOVA and a Tukey post-hoc test were used for data analysis. Mean percentages of MN were 1.82 ± 0.13, 5.20 ± 0.24, 3.32 ± 0.13, and 3.04 ± 0.12 in Groups I, II, III, and IV, respectively. The results indicate that tamoxifen and raloxifene similarly reduced the formation of MNPCE of female rats in persistent estrus (P < 0.0001 for Groups III and IV vs. Group II), using the dosages and time periods applied in the present study. The data suggest possibly antimutagenic effects of SERMs under high levels of estrogens. The findings also suggest that this is an interesting animal model for studying the genotoxicity of estrogens.

The clinical effectiveness and cost-effectiveness of genotyping for CYP2D6 for the management of women with breast cancer treated with tamoxifen: a systematic review.

BACKGROUND: Breast cancer is the most common cancer affecting women in the UK. Tamoxifen (TAM) is considered as the standard of care for many women with oestrogen receptor positive breast cancer. However, wide variability in the response of individuals to drugs at the same doses may occur, which may be a result of interindividual genetic differences (pharmacogenetics). TAM is known to be metabolised to its active metabolites N-desmethyl TAM and 4-hydroxytamoxifen by a number of CYP450 enzymes, including CYP2D6, CYP3A4, CYP2C9, CYP2C19 and CYP2B6. N-desmethyl TAM is further metabolised to endoxifen by CYP2D6. Endoxifen, which is also formed via the action of CYP2D6, is 30- to 100-fold more potent than TAM in suppressing oestrogen-dependent cell proliferation, and is considered an entity responsible for significant pharmacological effects of TAM. Thus, an association between the cytochrome P450 2D6 (CYP2D6) genotype and phenotype (expected drug effects) is believed to exist and it has been postulated that CYP2D6 testing may play a role in optimising an individual's adjuvant hormonal treatment. OBJECTIVES: To determine whether or not testing for cytochrome P450 2D6 (CYP2D6) polymorphisms in women with early hormone receptor positive breast cancer leads to improvement in outcomes, is useful for health decision-making and is a cost-effective use of health-care resources. DATA SOURCES: Relevant electronic databases and websites including MEDLINE, EMBASE and HuGENet [Centers for Disease Control and Prevention (Office of Public Health Genomics), Human Genome Epidemiology Network] were searched until July 2009. Further studies that became known to the authors via relevant conferences or e-mail alerts from an automatically updated search of the Scopus database were also included as the review progressed, up to March 2010. REVIEW METHODS: A systematic review of the clinical effectiveness and cost-effectiveness of CYP2D6 testing was undertaken. As it was not possible to conduct meta-analyses, data were extracted into structured tables and narratively discussed. An exploratory analysis of sensitivity and specificity was undertaken. A review of economic evaluations and models of CYP2D6 testing for patients treated with TAM was also carried out. RESULTS: A total of 25 cohorts were identified which examined clinical efficacy (overall survival and relapse/recurrence), adverse events and endoxifen plasma concentrations by genotype/phenotype. Significantly, six cohorts suggest extensive metabolisers (Ems) appear to have better outcomes than either poor metabolisers (PMs) or PMs + intermediate metabolisers in terms of relapse/recurrence; however, three cohorts report apparently poorer outcomes for EMs (albeit not statistically significant). There was heterogeneity across the studies in terms of the patient population, alleles tested and outcomes used and defined. One decision model proposing a strategy for CYP2D6 testing for TAM was identified, but this was not suitable for developing a model to examine the cost-effectiveness of CYP2D6 testing. It was not possible to produce a de novo model because of a lack of data to populate it. CONCLUSION: This is a relatively new area of research that is evolving rapidly and, although international consortia are collaborating, the data are limited and conflicting. Therefore, it is not possible to recommend pharmacogenetic testing in this patient population. Future research needs to focus on which alleles (including, or in addition to, those related to CYP2D6) reflect patient response, the link between endoxifen levels and clinical outcomes, and the appropriate pathways for implementation of such pharmacogenetic testing in patient care pathways.

Sensitivity and proportionality assessment of metabolites from microdose to high dose in rats using LC-MS/MS.

BACKGROUND: The objective of this study was to evaluate the sensitivity requirement for LC-MS/MS as an analytical tool to characterize metabolites in plasma and urine at microdoses in rats and to investigate proportionality of metabolite exposure from a microdose of 1.67 µg/kg to a high dose of 5000 µg/kg for atorvastatin, ofloxacin, omeprazole and tamoxifen. RESULTS: Only the glucuronide metabolite of ofloxacin, the hydroxylation metabolite of omeprazole and the hydration metabolite of tamoxifen were characterized in rat plasma at microdose by LC-MS/MS. The exposure of detected metabolites of omeprazole and tamoxifen appeared to increase in a nonproportional manner with increasing doses. Exposure of ortho- and para-hydroxyatorvastatin, but not atorvastatin and lactone, increased proportionally with increasing doses. CONCLUSION: LC-MS/MS has demonstrated its usefulness for detecting and characterizing the major metabolites in plasma and urine at microdosing levels in rats. The exposure of metabolites at microdose could not simply be used to predict their exposure at higher doses.

Assessment of vascular effects of tamoxifen and its metabolites on the rat perfused hindquarter vascular bed.

Tamoxifen has been suggested to produce beneficial cardiovascular effects, although the mechanisms for these effects are not fully known. Moreover, although tamoxifen metabolites may exhibit 30-100 times higher potency than the parent drug, no previous study has compared the effects produced by tamoxifen and its metabolites on vascular function. Here, we assessed the vascular responses to acetylcholine and sodium nitroprusside on perfused hindquarter vascular bed of rats treated with tamoxifen or its main metabolites (N-desmethyl-tamoxifen, 4-hydroxy-tamoxifen, and endoxifen) for 2 weeks. Plasma and whole-blood thiobarbituric acid reactive substances (TBARS) concentrations were determined using a fluorometric method. Plasma nitrite and NOx (nitrite + nitrate) concentrations were determined using an ozone-based chemiluminescence assay and Griess reaction, respectively. Treatment with tamoxifen reduced the responses to acetylcholine (pD(2) = 2.2 +/- 0.06 and 1.9 +/- 0.05 after vehicle and tamoxifen, respectively; P < 0.05), while its metabolites improved these responses (pD(2) = 2.5 +/- 0.04 after N-desmethyl-tamoxifen, 2.5 +/- 0.03 after 4-hydroxy-tamoxifen, and 2.6 +/- 0.08 after endoxifen; P < 0.01). Tamoxifen and its metabolites showed no effect on endothelial-independent responses to sodium nitroprusside (P > 0.05). While tamoxifen treatment resulted in significantly higher plasma and whole blood lipid peroxide levels (37% and 62%, respectively; both P < 0.05), its metabolites significantly decreased lipid peroxide levels (by approximately 50%; P < 0.05). While treatment with tamoxifen decreased the concentrations of markers of nitric oxide formation by approximately 50% (P < 0.05), tamoxifen metabolites had no effect on these parameters (P > 0.05). These results suggest that while tamoxifen produces detrimental effects, its metabolites produce counteracting beneficial effects on the vascular system and on nitric oxide/reactive oxygen species formation.

Antitumor efficacy testing in rodents.

The preclinical research and human clinical trials necessary for developing anticancer therapeutics are costly. One contributor to these costs is preclinical rodent efficacy studies, which, in addition to the costs associated with conducting them, often guide the selection of agents for clinical development. If inappropriate or inaccurate recommendations are made on the basis of these preclinical studies, then additional costs are incurred. In this commentary, I discuss the issues associated with preclinical rodent efficacy studies. These include the identification of proper preclinical efficacy models, the selection of appropriate experimental endpoints, and the correct statistical evaluation of the resulting data. I also describe important experimental design considerations, such as selecting the drug vehicle, optimizing the therapeutic treatment plan, properly powering the experiment by defining appropriate numbers of replicates in each treatment arm, and proper randomization. Improved preclinical selection criteria can aid in reducing unnecessary human studies, thus reducing the overall costs of anticancer drug development.

SERMs: meeting the promise of multifunctional medicines.

The successful development and clinical evaluation of the selective estrogen receptor modulators in the Study of Tamoxifen and Raloxifene trial provides an occasion to reflect on the milestone that has been achieved and the potential for further progress in the chemoprevention of breast cancer. The evolution of tamoxifen from a successful treatment for breast cancer to the first chemopreventive for any cancer took two decades. Clinicians gained an enormous amount of experience with the use of tamoxifen as a treatment, and, as a result, there were few surprises in terms of efficacy or the side effect profile when the medicine was used to prevent breast cancer in high-risk women. In contrast, raloxifene emerged via the novel path of the evidence-based hypothesis that a drug targeted at one disease, osteoporosis, could also prevent breast cancer. Changes in health care strategies to implement chemoprevention take time, but the evidence now suggests that chemoprevention has become a reality in clinical practice.

Pretreatment and prospective assessment of endometrium in menopausal women taking tamoxifen for breast cancer.

OBJECTIVES: To estimate the pretreatment incidence of endometrial pathology and to prospectively assess the endometrial morbidity emerging during tamoxifen intake for breast cancer. STUDY DESIGN: One-hundred and forty-six menopausal breast cancer patients, candidate to receive tamoxifen underwent endometrial assessment by Transvaginal Ultrasonography (TU) before the start of therapy. A double-layered endometrial stripe measuring more than 4mm indicated hysteroscopy and endometrial biopsy. Endometrial abnormalities detected before the start of tamoxifen were treated by operative hysteroscopy or by hysterectomy; no therapy and yearly hysteroscopic follow-up was scheduled for patients showing non-atypical hyperplasias. All women were asked to undergo TU on a yearly basis; during the follow-up period, indication for hysteroscopy and endometrial biopsy were the following: (i) an endometrial lining measured above 4mm at the first time, (ii) at least a 50% increase of endometrial thickness since the last finding in patients previously assessed by hysteroscopy, (iii) a recorded vaginal bleeding, and (iv) previous findings of endometrial hyperplasia. Histopathologic result from biopsy or hysterectomy was the reference test to establish the baseline prevalence of endometrial pathology and the emerging prevalences of morbidity after 12, 24, 36, 48 and 60 months of tamoxifen therapy. RESULTS: One-hundred and five patients were followed for 60 months, whereas 113, 126, 137 and 141 patients were evaluated up to 48, 36, 24 and 12 months, respectively. In 44 out of 146 patients, pretreatment TU showed an endometrium thicker than 4mm and in 31 (21.2%) of these patients abnormalities consisting of 16 endometrial polyps, seven polyps harboring simple hyperplasia, four simple hyperplasias, three atypical hyperplasias and one adenocarcinoma were found. During tamoxifen intake benign endometrial abnormalities were detected in 36 out of 114 assessable patients showing normal endometrium before the start of tamoxifen therapy (31.5%) and in seven out of 27 patients with baseline endometrial abnormalities (25.9%). Overall, an endometrial pathology emerged in 30.4% of patients during tamoxifen administration and in no patients we found an atypical lesion. CONCLUSIONS: In menopausal breast cancer patients the incidence of endometrial abnormalities before the start of tamoxifen therapy is high and includes 2.7% of atypical pathology. After the diagnosis and treatment of baseline atypical lesions were accomplished, no atypical endometrial lesion emerged after the start of tamoxifen administration. Based on these findings, we believe that pretreatment assessment of endometrium is recommended in all menopausal women candidate to receive tamoxifen therapy.

Incidence and management of side effects associated with aromatase inhibitors in the adjuvant treatment of breast cancer in postmenopausal women.

OBJECTIVE: Third-generation aromatase inhibitors (AIs) are effective and generally well-tolerated as adjuvant therapy. These AIs are now being introduced for the adjuvant treatment of postmenopausal patients with estrogen-receptor-positive early-stage breast cancer. However, questions remain about their long-term safety. This paper summarizes the adverse events reported in third-generation AI trials and comments on the appropriate management of these drug-induced adverse events in patients. METHODS: Papers relating to anastrozole, exemestane, and letrozole were identified through Medline searches, and proceedings of recent oncology meetings were also reviewed to capture relevant emerging data. RESULTS: The most commonly reported adverse events associated with adjuvant AI therapy include hot flushes and musculoskeletal complaints/arthralgia. The incidence of endometrial cancer and thromboembolic events is significantly lower with an AI than with tamoxifen. However, there is a small but significant increase in the risk of osteoporosis and fractures with AI therapy. A potential negative effect on the cardiovascular system, specifically on lipid metabolism, has not been conclusively demonstrated. No significant differences in overall quality of life were observed in studies comparing AIs with tamoxifen or placebo. CONCLUSION: AIs alone and sequenced after tamoxifen are an appropriate option for adjuvant endocrine therapy for most postmenopausal patients with hormone-responsive breast cancer. The incidence of some side effects such as endometrial cancer, stroke, or pulmonary embolism associated with tamoxifen is decreased. Monitoring and management of bone loss associated with AI treatment are essential and are being addressed in ongoing trials. Further studies with longer follow-up are required to clarify the effects of AIs on lipid metabolism and cardiovascular health.

Letrozole: a pharmacoeconomic review of its use in postmenopausal women with breast cancer.

Letrozole (Femara), an aromatase inhibitor that blocks estrogen synthesis by inhibiting the final step of the estrogen biosynthetic pathway, is approved for use in a wide range of breast cancer settings. Randomised clinical trials in postmenopausal women with hormone-responsive early-stage breast cancer have demonstrated that, as adjuvant therapy, letrozole has greater efficacy than tamoxifen. It is also more effective than placebo as extended adjuvant therapy after completion of tamoxifen therapy in these patients. In women with hormone-responsive advanced breast cancer, letrozole is superior to tamoxifen in prolonging the time to disease progression and time to treatment failure in a first-line setting, and is at least as effective as anastrozole and more effective than megestrol for some endpoints (in one of two trials) in a second-line setting. Letrozole is generally well tolerated, and in a health-related quality-of-life analysis from a large clinical trial, patient well-being with letrozole as extended adjuvant therapy did not differ from that with placebo. Modelled analyses from the UK and the US suggest that, in postmenopausal women with hormone-receptor-positive early-stage breast cancer, letrozole is likely to be a cost-effective alternative to tamoxifen as adjuvant therapy; moreover, using letrozole as extended adjuvant therapy after tamoxifen, rather than no further treatment, is also a cost-effective treatment strategy. Sensitivity analyses have shown these results to be robust. In terms of direct healthcare costs, pharmacoeconomic models suggest that letrozole is a cost-effective alternative to tamoxifen as first-line therapy in postmenopausal women with hormone-responsive advanced breast cancer from the perspectives of the UK NHS, the Canadian and Italian public healthcare systems and the Japanese national health insurance system. Incremental costs per QALY or progression-free year gained over tamoxifen were well within the recommended limits for acceptability of new agents that are more effective and more expensive than existing therapies in the UK, Japan and Canada. Modelled analyses from the UK and Canada have also suggested that letrozole is cost effective as second-line therapy for advanced breast cancer in postmenopausal women who have disease progression following anti-estrogen therapy. In conclusion, letrozole is an effective and well tolerated treatment for postmenopausal women with early-stage or advanced hormone-responsive breast cancer. Pharmacoeconomic analyses from UK and North American perspectives support the use of letrozole in hormone-responsive early-stage breast cancer in both the adjuvant and extended adjuvant settings. In addition, other modelled analyses conducted in a variety of healthcare systems across different countries consistently suggest that letrozole is cost effective in advanced treatment settings.

Endometrial cells in cervical cytology: review of cytological features and clinical assessment.

The 2001 Bethesda System for Reporting Cervical Cytology recommends reporting benign exfoliated endometrial cells in women age 40 and older, and a review of the literature supports this recommendation. Stromal cells and histiocytes do not need to be reported. The effect of hormonal therapy on endometrial shedding is reviewed. Clinical information should be provided to the laboratory so that appropriate educational notes can be appended to the cytology report. Benign endometrial cells in premenopausal women in the first half of the cycle are not associated with significant pathology and such women do not need additional evaluation. Significant pathology is also unlikely in the second half of the cycle and evaluation may not be required unless clinically indicated. Initial evaluation of other women with benign endometrial cells may include either endometrial sampling or transvaginal ultrasound. Atypical endometrial cells are associated with a higher rate of significant pathology and should lead to additional evaluation. Additional prospective studies on the management of patients with endometrial cells on Pap tests are needed.