Activating adaptive cellular mechanisms of resistance following sublethal cytotoxic chemotherapy: implications for diagnostic microdosing.

As Phase 0 studies have proven to be reasonably predictive of therapeutic dose pharmacokinetics, the application of microdosing has expanded into metabolism, drug-drug interactions and now diagnostics. One potentially serious issue with this application of microdosing that has not been previously discussed is the possibility of activating cellular mechanisms of drug resistance. Here, we provide an overview of Phase 0 microdosing and drug resistance, with an emphasis on cisplatin resistance, followed by a discussion of the potential for inducing acquired resistance to platinum-based or other types of chemotherapy in cancer patients participating in Phase 0 diagnostic microdosing studies. A number of alternative approaches to diagnostic microdosing, such as the human tumor cloning assay and the use of peripheral blood mononuclear cells as a surrogate for measuring DNA adducts, are discussed that would avoid exposing cancer patients to low doses of first-line chemotherapy and the possible risk of triggering cellular mechanisms of acquired resistance. Until it has been established that diagnostic microdosing in cancer patients poses no risk of acquired drug resistance, such studies should be approached with caution.

Complexity of Translating Analytics to Recent Cannabis Use and Impairment.

While current analytical methodologies can readily identify cannabis use, definitively establishing recent use within the impairment window has proven to be far more complex, requiring a new approach. Recent studies have shown no direct relationship between impairment and Δ9-tetra-hydrocannabinol (Δ9-THC) concentrations in blood or saliva, making legal "per se" Δ9-THC limits scientifically unjustified. Current methods that focus on Δ9-THC and/or metabolite concentrations in blood, saliva, urine, or exhaled breath can lead to false-positive results for recent use due to the persistence of Δ9-THC well outside of the typical 3-4 h window of potential impairment following cannabis inhalation. There is also the issue of impairment due to other intoxicating substances-just because a subject exhibits signs of impairment and cannabis use is detected does not rule out the involvement of other drugs. Compounding the matter is the increasing popularity of hemp-derived cannabidiol (CBD) products following passage of the 2018 Farm Bill, which legalized industrial hemp in the United States. Many of these products contain varying levels of Δ9-THC, which can lead to false-positive tests for cannabis use. Furthermore, hemp-derived CBD is used to synthesize Δ8-THC, which possesses psychoactive properties similar to Δ9-THC and is surrounded by legal controversy. For accuracy, analytical methods must be able to distinguish the various THC isomers, which have identical masses and exhibit immunological cross-reactivity. A new testing approach has been developed based on exhaled breath and blood sampling that incorporates kinetic changes and the presence of key cannabinoids to detect recent cannabis use within the impairment window without the false-positive results seen with other methods. The complexity of determining recent cannabis use that may lead to impairment demands such a comprehensive method so that irresponsible users can be accurately detected without falsely accusing responsible users who may unjustly suffer harsh, life-changing consequences.

Antitumor effects of L-BLP25 antigen-specific tumor immunotherapy in a novel human MUC1 transgenic lung cancer mouse model.

BACKGROUND: L-BLP25 antigen-specific cancer immunotherapeutic agent is currently in phase III clinical trials for non-small cell lung cancer. Using a novel human MUC1 transgenic (hMUC1.Tg) lung cancer mouse model, we evaluated effects of L-BLP25 combined with low-dose cyclophosphamide (CPA) pretreatment on Th1/Th2 cytokine production and antitumor activity. METHODS: A chemically-induced lung tumor model was developed in hMUC1.Tg C57BL/6 mice by administering 10 weekly 0.75-mg/g doses of the chemical carcinogen urethane by intraperitoneal injection. Serum cytokines associated with Th1/Th2 polarization and inflammation were measured by multiplex cytokine assay during tumorigenesis. Antitumor activity of L-BLP25 (10 µg) with CPA (100 mg/kg) pretreatment was evaluated following either one or two eight-week cycles of treatment by preparing lung whole mounts and counting tumor foci, and assessing IFN-γ production by ELISpot assay. RESULTS: During the carcinogenesis phase, no detectable Th1- or Th2-associated cytokine responses were observed, but levels of pro-inflammatory cytokines were increased with distinctive kinetics. A single cycle of L-BLP25 consisting of eight weekly doses was ineffective, whereas adding a second cycle given during tumor progression showed a significant reduction in the incidence of tumor foci. Administering two cycles of L-BLP25 induced Th1 cytokines IL-12, IL-2 and IFNγ at 24 h after the last dose, while Th2 and inflammatory cytokines were elevated to a lesser extent. CONCLUSIONS: Urethane-induced lung tumors in hMUC1.Tg mice can be used as a model to assess the efficacy of the MUC1 antigen-specific cancer immunotherapeutic agent L-BLP25. The results indicate that the antitumor response to L-BLP25 requires at least two cycles and pre-treatment with CPA. In addition, monitoring pro-inflammatory serum cytokines may be useful as a biomarker of L-BLP25 response. Taken together, the preclinical lung tumor model can be utilized for determining effective combinations of L-BLP25 with chemotherapy and/or other immunotherapies.

Indeterminacy of cannabis impairment and ∆9-tetrahydrocannabinol (∆9-THC) levels in blood and breath.

Previous investigators have found no clear relationship between specific blood concentrations of ∆9-tetrahydrocannabinol (∆9-THC) and impairment, and thus no scientific justification for use of legal "per se" ∆9-THC blood concentration limits. Analyzing blood from 30 subjects showed ∆9-THC concentrations that exceeded 5 ng/mL in 16 of the 30 subjects following a 12-h period of abstinence in the absence of any impairment. In blood and exhaled breath samples collected from a group of 34 subjects at baseline prior to smoking, increasing breath ∆9-THC levels were correlated with increasing blood levels (P < 0.0001) in the absence of impairment, suggesting that single measurements of ∆9-THC in breath, as in blood, are not related to impairment. When post-smoking duration of impairment was compared to baseline ∆9-THC blood concentrations, subjects with the highest baseline ∆9-THC levels tended to have the shortest duration of impairment. It was further shown that subjects with the shortest duration of impairment also had the lowest incidence of horizontal gaze nystagmus at 3 h post-smoking compared to subjects with the longest duration of impairment (P < 0.05). Finally, analysis of breath samples from a group of 44 subjects revealed the presence of transient cannabinoids such as cannabigerol, cannabichromene, and ∆9-tetrahydrocannabivarin during the peak impairment window, suggesting that these compounds may be key indicators of recent cannabis use through inhalation. In conclusion, these results provide further evidence that single measurements of ∆9-THC in blood, and now in exhaled breath, do not correlate with impairment following inhalation, and that other cannabinoids may be key indicators of recent cannabis inhalation.

Examining impairment and kinetic patterns associated with recent use of hemp-derived Δ8-tetrahydrocannabinol: case studies.

BACKGROUND: As a result of the legalization of U.S. industrial hemp production in late 2018, products containing hemp-derived Δ8-tetrahydrocannabinol (Δ8-THC) are increasing in popularity. Little, however, is known regarding Δ8-THC's impairment potential and the associated impacts on roadway and workplace safety, and testing for Δ8-THC is not yet common. The present study explored impairment patterns and cannabinoid kinetics associated with recent use of Δ8-THC. METHODS: Hemp-derived Δ8-THC concentrate was administered by vaporization ad libitum to three male frequent cannabis users aged 23-25 years. In addition to self-assessments of impairment using a 10-point scale, horizontal gaze nystagmus (HGN) was evaluated in each subject as a physical means of assessing impairment before and after vaporization. To examine cannabinoid kinetic patterns, exhaled breath and capillary blood samples were collected prior to vaporization up to 180 min post-vaporization and analyzed by liquid chromatography high-resolution mass spectrometry for cannabinoid content using validated methods. The impairment and cannabinoid kinetic results were then compared to analogous results obtained from the same three subjects after they had smoked a ∆9-THC cannabis cigarette ad libitum in a previous study to determine whether any similarities existed. RESULTS: Patterns of impairment after vaporizing Δ8-THC were similar to those observed after smoking cannabis, with self-assessed impairment peaking within the first hour after use, and then declining to zero by 3 h post-use. Likewise, HGN was observed only after vaporizing, and by 3 h post-vaporization, evidence of HGN had dissipated. Cannabinoid kinetic patterns observed after vaporizing Δ8-THC (short ∆8-THC half-lives of 5.2 to 11.2 min at 20 min post-vaporization, presence of key cannabinoids cannabichromene, cannabigerol, and tetrahydrocannabivarin, and breath/blood Δ8-THC ratios > 2 within the first hour post-vaporization) were also analogous to those observed for ∆9-THC and the same key cannabinoids within the first hour after the same subjects had smoked cannabis in the previous study. CONCLUSIONS: Hemp-derived Δ8-THC and Δ9-THC from cannabis display similar impairment profiles, suggesting that recent use of Δ8-THC products may carry the same risks as cannabis products. Standard testing methods need to incorporate this emerging, hemp-derived cannabinoid.

A comprehensive breath test that confirms recent use of inhaled cannabis within the impairment window.

Legalization of cannabis for medicinal and/or recreational use is expanding globally. Although cannabis is being regulated country by country, an accurate recent use test with indisputable results correlated with impairment has yet to be discovered. In the present study, a new approach for determining recent cannabis use within the impairment window after smoking was developed by studying 74 subjects with a mean age of 25 years and average use history of 9 years. Horizontal gaze nystagmus was evaluated along with subject self-assessments of impairment, and blood and breath samples were collected before and after smoking cannabis. Breath and blood pharmacokinetic parameters and cannabinoid profiles determined recent use within the impairment window. No subjects were positive for recent use pre-smoking, although all subjects had detectable cannabinoids in breath samples. We describe an inhaled cannabis recent use test that correlates with impairment and helps protect against wrongful prosecution and workplace discrimination.

Development and Validation of a Liquid Chromatography High-Resolution Mass Spectrometry (LC-HRMS) Bioanalytical Method for Quantifying Cannabinoids in Whole Blood: Application for Determining Recent Cannabis Use.

BACKGROUND: Cannabis legalization is expanding rapidly throughout the United States, but there is no reliable means of establishing recent use. OBJECTIVE: To develop and validate a bioanalytical method for determination of Δ9-tetrahydrocannabinol (Δ9-THC), cannabinol, 11-hydroxy-Δ9-THC, 11-nor-9-carboxy-Δ9-THC, and 8ß,11-dihydroxy-Δ9-THC in whole blood microsamples by liquid chromatography high-resolution mass spectrometry (LC-HRMS). METHODS: Cannabinoid extraction from whole blood was performed using a mixture of n-hexane/ethyl acetate (90:10, v/v). Chromatographic separation was performed with a C18 column using a binary mobile phase gradient of water and acetonitrile, each with 0.1% formic acid. Detection was performed by positive ion mode heated electrospray ionization with full scan MS on an Orbitrap mass spectrometer. A clinical study was performed in 30 subjects to identify recent cannabis use based on analysis of cannabinoids in blood samples up to 200 min post-smoking. RESULTS: Acceptable linearity of all calibration curves was observed (r2>0.99) for all analytes over a 1-100 ng/mL concentration range, with acceptable accuracy. Limit of detection (LOD) was 0.5 ng/mL. Accuracy and precision met acceptance criteria for all analytes. Repeatability (CV) was <5% at low (3 ng/mL) and high (90 ng/mL) concentrations. In the clinical study, the ratios between 11-nor-9-carboxy-Δ9-THC and Δ9-THC fell immediately after smoking and returned to near baseline levels by 200 min post-smoking, which is consistent with recent use. CONCLUSIONS AND HIGHLIGHTS: The developed LC-HRMS bioanalytical method is suitable for quantification of five key cannabinoids in whole capillary blood microsamples and can be used in conjunction with a test for determining recent cannabis use.

Repurposing ospemifene for potentiating an antigen-specific immune response.

OBJECTIVE: Ospemifene, an estrogen receptor agonist/antagonist approved for the treatment of dyspareunia and vaginal dryness in postmenopausal women, has potential new indications as an immune modulator. The overall objective of the present series of preclinical studies was to evaluate the immunomodulatory activity of ospemifene in combination with a peptide cancer vaccine. METHODS: Immune regulating effects, mechanism of action and structure activity relationships of ospemifene and related compounds were evaluated by examining expression of T-cell activating cytokines in vitro, and antigen-specific immune response and cytotoxic T-lymphocyte activity in vivo. The effects of ospemifene (OSP) on the immune response to a peptide cancer vaccine (PV) were evaluated after chronic [control (n = 22); OSP 50 mg/kg (n = 16); PV (n = 6); OSP+PV (n = 11)], intermittent [control (n = 10); OSP 10 and 50 mg/kg (n = 11); PV (n = 11); combination treatment (n = 11 each dose)] and pretreatment [control; OSP 100 mg/kg; PV 100 µg; combination treatment (n = 8 all groups)] ospemifene oral dosing schedules in a total of 317 mixed-sex tumor-bearing and nontumor-bearing mice. RESULTS: The results showed that ospemifene induced expression of the key TH1 cytokines interferon gamma and interleukin-2 in vitro, which may be mediated by stimulating T-cells through phosphoinositide 3-kinase and calmodulin signaling pathways. In combination with an antigen-specific peptide cancer vaccine, ospemifene increased antigen-specific immune response and increased cytotoxic T-lymphocyte activity in tumor-bearing and nontumor-bearing mice. The pretreatment, intermittent, and chronic dosing schedules of ospemifene activate naive T-cells, modulate antigen-induced tolerance and reduce tumor-associated, pro-inflammatory cytokines, respectively. CONCLUSIONS: Taken together, ospemifene's dose response and schedule-dependent immune modulating activity offers a method of tailoring and augmenting the efficacy of previously failed antigen-specific cancer vaccines for a wide range of malignancies.

Ineffectiveness of American ginseng in the prevention of dimethylbenzanthracene-induced mammary tumors in mice.

The potential of American ginseng (AG) ( Panax quinquefolium), a commonly used herbal remedy believed to have anticarcinogenic effects, to prevent the development of mammary tumors was evaluated in a mouse model of dimethylbenzanthracene (DMBA)-induced mammary carcinoma. Ginsenosides, believed to be the active components of ginseng and that have a chemical structure similar to estradiol, have previously been shown to possess phytoestrogen-like qualities similar to the soy isoflavone genistein. The effects of AG, administered as powdered root, were compared to the selective estrogen receptor modulators tamoxifen and ospemifene. Eighty-three female SENCAR mice were divided into four treatment groups: control (N = 23), AG (N = 20), ospemifene (N = 20), and tamoxifen (N = 20). American ginseng, ospemifene, and tamoxifen were administered at a dose of 50 mg/kg/day orally by gavage, with the control mice receiving vehicle only. For the first 6 weeks, all mice received 20 microg/day DMBA in combination with their respective treatments. DMBA was then withdrawn, and daily treatments continued for a total of approximately 52 weeks. As expected, ospemifene (p = 0.01) and tamoxifen (p = 0.004) significantly reduced the incidence of mammary tumors compared to the control mice, which had a mammary tumor incidence of approximately 57%. The incidence of mammary carcinomas in the AG group was 40%, a reduction of approximately 29% compared to control. These results suggest that AG may still have the potential to prevent the development of mammary tumors in a chemically induced breast cancer mouse model, although the present study showed no significant difference between control and AG-treated mice.

Novel cancer antigens for personalized immunotherapies: latest evidence and clinical potential.

The clinical success of monoclonal antibody immune checkpoint modulators such as ipilimumab, which targets cytotoxic T lymphocyte-associated antigen 4 (CTLA-4), and the recently approved agents nivolumab and pembrolizumab, which target programmed cell death receptor 1 (PD-1), has stimulated renewed enthusiasm for anticancer immunotherapy, which was heralded by Science as 'Breakthrough of the Year' in 2013. As the potential of cancer immunotherapy has been recognized since the 1890s when William Coley showed that bacterial products could be beneficial in cancer patients, leveraging the immune system in the treatment of cancer is certainly not a new concept; however, earlier attempts to develop effective therapeutic vaccines and antibodies against solid tumors, for example, melanoma, frequently met with failure due in part to self-tolerance and the development of an immunosuppressive tumor microenvironment. Increased knowledge of the mechanisms through which cancer evades the immune system and the identification of tumor-associated antigens (TAAs) and negative immune checkpoint regulators have led to the development of vaccines and monoclonal antibodies targeting specific tumor antigens and immune checkpoints such as CTLA-4 and PD-1. This review first discusses the established targets of currently approved cancer immunotherapies and then focuses on investigational cancer antigens and their clinical potential. Because of the highly heterogeneous nature of tumors, effective anticancer immunotherapy-based treatment regimens will likely require a personalized combination of therapeutic vaccines, antibodies and chemotherapy that fit the specific biology of a patient's disease.

Selective estrogen receptor modulators inhibit growth and progression of premalignant lesions in a mouse model of ductal carcinoma in situ.

INTRODUCTION: Ductal carcinoma in situ (DCIS) is a noninvasive premalignant lesion and is considered a precursor to invasive carcinoma. DCIS accounts for nearly 20% of newly diagnosed breast cancer, but the lack of experimentally amenable in vivo DCIS models hinders the development of treatment strategies. Here, we demonstrate the utility of a mouse transplantation model of DCIS for chemoprevention studies using selective estrogen receptor modulators (SERMs). This model consists of a set of serially transplanted lines of genetically engineered mouse mammary intraepithelial neoplasia (MIN) outgrowth (MIN-O) tissue that have stable characteristics. We studied the ovarian-hormone-responsiveness of one of the lines with a particular focus on the effects of two related SERMs, tamoxifen and ospemifene. METHODS: The estrogen receptor (ER) status and ovarian-hormone-dependence of the mouse MIN outgrowth tissue were determined by immunohistochemistry and ovarian ablation. The effects of tamoxifen and ospemifene on the growth and tumorigenesis of MIN outgrowth were assessed at 3 and 10 weeks after transplantation. The effects on ER status, cell proliferation, and apoptosis were studied with immunohistochemistry. RESULTS: The MIN-O was ER-positive and ovarian ablation resulted in reduced MIN-O growth and tumor development. Likewise, tamoxifen and ospemifene treatments decreased the MIN growth and tumor incidence in comparison with the control (P < 0.01). Both SERMs significantly decreased cell proliferation. Between the two SERM treatment groups, there were no statistically significant differences in MIN-O size, tumor latency, or proliferation rate. In contrast, the ospemifene treatment significantly increased ER levels while tamoxifen significantly decreased them. CONCLUSION: Tamoxifen and ospemifene inhibit the growth of premalignant mammary lesions and the progression to invasive carcinoma in a transplantable mouse model of DCIS. The inhibitory effects of these two SERMs are similar except for their effects on ER modulation. These differences in ER modulation may suggest different mechanisms of action between the two related SERMs and may portend different long-term outcomes. These data demonstrate the value of this model system for preclinical testing of antiestrogen or other therapies designed to prevent or delay the malignant transformation of premalignant mammary lesions in chemoprevention.

Effects of ospemifene and raloxifene on hormonal status, lipids, genital tract, and tolerability in postmenopausal women.

OBJECTIVE: To compare ospemifene and raloxifene regarding their effects on hormones, lipids, genital tract, and tolerability in postmenopausal women. DESIGN: A randomized, double-blind study in which 118 healthy postmenopausal women received 30 (n = 29), 60 (n = 30), or 90 mg (n = 30) of ospemifene or 60 mg (n = 29) of raloxifene for 3 months. RESULTS: There were no significant differences in the baseline characteristics between study groups. In comparison with raloxifene, follicle-stimulating hormone levels decreased significantly more in the 90-mg ospemifene group and sex hormone-binding globulin levels increased more in all ospemifene groups. Total cholesterol and low-density lipoprotein cholesterol levels decreased more in raloxifene than in ospemifene groups, although the difference in low-density lipoprotein cholesterol between 90-mg ospemifene and raloxifene was not significant. Endometrial thickness did not change in any study group and endometrial biopsies showed atrophy in the majority of subjects at 3 months. All ospemifene groups demonstrated a clear estrogenic effect on the vaginal epithelium, as seen in Pap smears. This was in sharp contrast to the raloxifene group, which had no effect on the vaginal epithelium. Kupperman index decreased in all study groups during treatment. The adverse events were mild, mainly single cases, and no clustering of events was observed. There were no clinically significant abnormal findings in laboratory safety parameters. CONCLUSIONS: Ospemifene, at the dose of 90 mg/day, was more estrogenic than raloxifene, as shown by changes in serum follicle-stimulating hormone and sex hormone-binding globulin levels. Neither agent stimulated endometrium, but in contrast to raloxifene, ospemifene had a clear estrogenic effect in the vagina. Further studies with ospemifene are needed in subjects with vaginal atrophy.

Ospemifene inhibits the growth of dimethylbenzanthracene-induced mammary tumors in Sencar mice.

Ospemifene is a new selective estrogen receptor modulator (SERM) that is being developed for the treatment of urogenital atrophy and osteoporosis. Similarly to other SERMs, ospemifene exhibits antiestrogenic effects in breast tissue, which led to the hypothesis that it may be a potential breast cancer chemopreventive agent. We first assessed the ability of ospemifene, compared to tamoxifen and raloxifene, to prevent dimethylbenzanthracene (DMBA)-induced mammary tumors in female Sencar mice. Ospemifene (N = 18), tamoxifen (N = 20) and raloxifene (N = 17), each dosed at 50 mg/kg, were administered daily by oral gavage, in combination with 20 microg DMBA for the first 6 weeks. Control mice (N = 21) received vehicle plus DMBA only for the first 6 weeks. Daily treatment then continued for 37 weeks. As hypothesized, ospemifene greatly reduced the incidence of mammary carcinomas compared to control mice (p = 0.003), similar to tamoxifen (p = 0.0004); however, in the raloxifene group, no significant effect was seen in mammary tumor prevention (p = 0.20). A follow-up study comparing ospemifene (N = 20) to tamoxifen (N = 20) in the same model was then performed to confirm the results of the first study. The results of the follow-up study, which extended the treatment to 52 weeks, confirmed the results of our previous study, with ospemifene (p = 0.01) and tamoxifen (p = 0.004) significantly decreasing mammary carcinomas compared to controls. The results of these two studies suggest that women taking ospemifene for osteoporosis and/or urogenital atrophy may further benefit from ospemifene's breast cancer chemopreventive effects.

Assessing the Effects of Concurrent versus Sequential Cisplatin/Radiotherapy on Immune Status in Lung Tumor-Bearing C57BL/6 Mice.

Concurrent and sequential cisplatin-based chemoradiotherapy regimens are standard therapeutic approaches in cancer treatment. Recent clinical data suggest that these different dosing schedules may adversely affect antigen-specific immunotherapy. The goal of the present preclinical study was to explore the effects of concurrent and sequential cisplatin/radiotherapy on immune status in a lung cancer mouse model. A total of 150 C57BL/6 mice were randomized into six treatment groups: control; 8 Gy thoracic radiotherapy (dose schedules 1 and 2); cisplatin 2.5 mg/kg i.p.; cisplatin + radiotherapy (concurrent); and cisplatin + radiotherapy (sequential; n = 25, all groups). At the end of the study (week 41), serum cytokines were assessed by multiplex immunoassay, surface markers of spleen-derived lymphocytes were assessed by immunostaining and flow cytometry, lung tumor expression of programmed death ligands 1 and 2 (PD-L1/2) was evaluated by immunohistochemistry, and miRNA profiling was performed in serum and lymphocytes by quantitative real-time PCR. Lung whole mounts were prepared to assess treatment effects on lung tumor foci formation. The results showed that sequential chemoradiotherapy (two cycles of cisplatin followed by 8 Gy radiotherapy) had equivalent antitumor activity as concurrent therapy. However, sequential cisplatin/radiotherapy resulted in significant differences in several immune response biomarkers, including regulatory T cells, miR-29c, expression of costimulatory molecule CD28, and serum IFNγ. PD-L1 and PD-L2 were strongly expressed in tumor foci, but no trend was seen between groups. These results suggest that monitoring immune status may be necessary when designing treatment regimens combining immunotherapy with chemoradiotherapy.

SERMs: current status and future trends.

Selective estrogen receptor modulators, or SERMs, are a class of compounds that can act as estrogen receptor (ER) agonists in some tissues while acting as ER antagonists in others. SERMs are being evaluated and used to treat and prevent such diseases as breast cancer, osteoporosis, and cardiovascular disease. Currently, three primary SERMs are used clinically, which include tamoxifen, toremifene (triphenylethylenes), and raloxifene (a benzothiophene). Tamoxifen and toremifene have beneficial effects on bone and serum lipids, and are currently used to treat breast cancer. Both have stimulatory effects on the uterus. Raloxifene, indicated for the treatment and prevention of osteoporosis, also has beneficial effects on bone and serum lipids, but does not stimulate the uterus. All three are associated with venous thromboembolism and hot flashes. New SERMs to treat and prevent breast cancer, osteoporosis, and cardiovascular disease are undergoing clinical development, including idoxifene, droloxifene, ospemifene, lasofoxifene, arzoxifene, and MDL 103,323.

Pharmacokinetics of selective estrogen receptor modulators.

Selective estrogen receptor modulators (SERMs) are a class of compounds used to treat and prevent breast cancer and osteoporosis. SERMs currently approved for use in patients include tamoxifen, toremifene and raloxifene. These compounds are well tolerated in patients, and the most common adverse effects experienced in patients undergoing SERM therapy include vasomotor symptoms such as hot flashes and vaginal discharge. New SERMs currently under development for use in the treatment and prevention of osteoporosis and breast cancer include ospemifene, a derivative of toremifene, and arzoxifene, a compound very similar in structure to raloxifene. SERMs are administered orally at doses ranging from 20 to 60 mg/day. Tamoxifen and toremifene have a bioavailability of approximately 100%, whereas that of raloxifene is only 2%. SERMs are very highly bound to plasma proteins (>95%). Tamoxifen and toremifene are metabolised by the cytochrome p450 enzyme system, and raloxifene is metabolised by glucuronide conjugation. The terminal elimination half-lives of these drugs range from 27.7 hours to 7 days. The pharmacokinetics of these compounds are affected in hepatically impaired patients, but not in renally impaired patients. SERMs have several potential drug interactions with other agents, such as warfarin, rifampicin (rifampin), cholestyramine and aromatase inhibitors.

Safety and efficacy of ospemifene for the treatment of dyspareunia associated with vulvar and vaginal atrophy due to menopause.

During the menopausal transition, women experience a number of symptoms due to declining estrogen levels, including vasomotor symptoms and vulvar and vaginal atrophy (VVA). Unlike vasomotor symptoms, vaginal dryness and dyspareunia, the main symptoms of VVA, typically worsen without treatment and can significantly impact the quality of life. Up to 60% of postmenopausal women may be affected by VVA, but many women unfortunately do not seek treatment due to embarrassment or other factors. After 20+ years in development, ospemifene (Osphena™) was approved by the US Food and Drug Administration in 2013 for treatment of moderate-to-severe dyspareunia associated with VVA due to menopause. As the first non-hormonal alternative to estrogen-based products for this indication, the approval of ospemifene represents a significant milestone in postmenopausal women's health. Ospemifene is a non-steroidal estrogen receptor agonist/antagonist, also known as a selective estrogen receptor modulator (SERM), from the same chemical class as the breast cancer drugs tamoxifen and toremifene. Unlike other selective estrogen receptor modulators, ospemifene exerts a strong, nearly full estrogen agonist effect in the vaginal epithelium, making it well suited for the treatment of dyspareunia in postmenopausal women. Results of Phase III clinical trials showed that ospemifene significantly improved the vaginal maturation index (decreased parabasal cells and increased superficial cells), decreased vaginal pH, and decreased severity of the self-identified most bothersome symptom (dyspareunia or vaginal dryness) compared to placebo. Long-term safety studies revealed that 60 mg ospemifene given daily for 52 weeks was well tolerated and was not associated with any endometrium or breast-related safety concerns. This review discusses the preclinical and clinical data supporting the use of ospemifene for the treatment of dyspareunia associated with VVA due to menopause and provides an overview of its clinical safety.

Ospemifene: a first-in-class, non-hormonal selective estrogen receptor modulator approved for the treatment of dyspareunia associated with vulvar and vaginal atrophy.

Ospemifene is a selective estrogen receptor modulator (SERM) approved for the treatment of dyspareunia associated with vulvar and vaginal atrophy (VVA) due to menopause. As the first non-hormonal treatment for this indication, the approval of ospemifene represents a significant milestone in postmenopausal women's health. Ospemifene is a triphenylethylene similar in chemical structure to tamoxifen and toremifene. Consistent with other SERMs such as tamoxifen, toremifene, and raloxifene, ospemifene possesses a distinctive mix of estrogenic and antiestrogenic tissue-specific effects in bone, breast tissue, serum lipids, and the vagina. Among the approved SERMs, ospemifene is the only agent with a nearly full estrogen agonist effect on the vaginal epithelium while having neutral to slight estrogenic effects in the endometrium, making ospemifene uniquely suited for the treatment of dyspareunia associated with VVA, also known as atrophic vaginitis, which affects up to 50% of postmenopausal women. This review begins with a brief history of the discovery of ospemifene, its mechanism of action, and its preclinical development, with an emphasis on its tissue-specific effects on bone, breast, uterus and endometrium, serum lipids and vagina. A brief discussion on the genotoxicity of ospemifene compared to tamoxifen and toremifene is included. The focus then shifts to the clinical development of ospemifene from Phase I through Phase III. We will close with the FDA approval of ospemifene and a justification of the future clinical evaluation of ospemifene as a potential breast cancer chemopreventive agent, where several preclinical studies in different rodent breast cancer models strongly suggest ospemifene is as effective as tamoxifen.

Tecemotide: an antigen-specific cancer immunotherapy.

The identification of tumor-associated antigens (TAA) has made possible the development of antigen-specific cancer immunotherapies such as tecemotide. One of those is mucin 1 (MUC1), a cell membrane glycoprotein expressed on some epithelial tissues such as breast and lung. In cancer, MUC1 becomes overexpressed and aberrantly glycosylated, exposing the immunogenic tandem repeat units in the extracellular domain of MUC1. Designed to target tumor associated MUC1, tecemotide is being evaluated in Phase III clinical trials for treatment of unresectable stage IIIA/IIIB non-small cell lung cancer (NSCLC) as maintenance therapy following chemoradiotherapy. Additional Phase II studies in other indications are ongoing. This review discusses the preclinical and clinical development of tecemotide, ongoing preclinical studies of tecemotide in human MUC1 transgenic mouse models of breast and lung cancer, and the potential application of these models for optimizing the timing of chemoradiotherapy and tecemotide immunotherapy to achieve the best treatment outcome for patients.