Research Progress on Spike-Dependent SARS-CoV-2 Fusion Inhibitors and Small Molecules Targeting the S2 Subunit of Spike.

Since the beginning of the COVID-19 pandemic, extensive drug repurposing efforts have sought to identify small-molecule antivirals with various mechanisms of action. Here, we aim to review research progress on small-molecule viral entry and fusion inhibitors that directly bind to the SARS-CoV-2 Spike protein. Early in the pandemic, numerous small molecules were identified in drug repurposing screens and reported to be effective in in vitro SARS-CoV-2 viral entry or fusion inhibitors. However, given minimal experimental information regarding the exact location of small-molecule binding sites on Spike, it was unclear what the specific mechanism of action was or where the exact binding sites were on Spike for some inhibitor candidates. The work of countless researchers has yielded great progress, with the identification of many viral entry inhibitors that target elements on the S1 receptor-binding domain (RBD) or N-terminal domain (NTD) and disrupt the S1 receptor-binding function. In this review, we will also focus on highlighting fusion inhibitors that target inhibition of the S2 fusion function, either by disrupting the formation of the postfusion S2 conformation or alternatively by stabilizing structural elements of the prefusion S2 conformation to prevent conformational changes associated with S2 function. We highlight experimentally validated binding sites on the S1/S2 interface and on the S2 subunit. While most substitutions to the Spike protein to date in variants of concern (VOCs) have been localized to the S1 subunit, the S2 subunit sequence is more conserved, with only a few observed substitutions in proximity to S2 binding sites. Several recent small molecules targeting S2 have been shown to have robust activity over recent VOC mutant strains and/or greater broad-spectrum antiviral activity for other more distantly related coronaviruses.

The Dual-Targeted Fusion Inhibitor Clofazimine Binds to the S2 Segment of the SARS-CoV-2 Spike Protein.

Clofazimine and Arbidol have both been reported to be effective in vitro SARS-CoV-2 fusion inhibitors. Both are promising drugs that have been repurposed for the treatment of COVID-19 and have been used in several previous and ongoing clinical trials. Small-molecule bindings to expressed constructs of the trimeric S2 segment of Spike and the full-length SARS-CoV-2 Spike protein were measured using a Surface Plasmon Resonance (SPR) binding assay. We demonstrate that Clofazimine, Toremifene, Arbidol and its derivatives bind to the S2 segment of the Spike protein. Clofazimine provided the most reliable and highest-quality SPR data for binding with S2 over the conditions explored. A molecular docking approach was used to identify the most favorable binding sites on the S2 segment in the prefusion conformation, highlighting two possible small-molecule binding sites for fusion inhibitors. Results related to molecular docking and modeling of the structure-activity relationship (SAR) of a newly reported series of Clofazimine derivatives support the proposed Clofazimine binding site on the S2 segment. When the proposed Clofazimine binding site is superimposed with other experimentally determined coronavirus structures in structure-sequence alignments, the changes in sequence and structure may rationalize the broad-spectrum antiviral activity of Clofazimine in closely related coronaviruses such as SARS-CoV, MERS, hCoV-229E, and hCoV-OC43.

Lipid changes during endocrine therapy in early-stage breast cancer patients: A real-world study.

BACKGROUND: Endocrine drugs may affect lipid metabolism in breast cancer (BC) patients. This study explores lipid changes in early-stage BC patients taking different endocrine drugs. METHODS: The changing trend of blood lipid during endocrine therapy in 2756 BC patients from January 2013 to December 2021 was retrospectively analyzed. The changes in four lipid parameters were assessed by the Generalized Linear Mixed Model, including total cholesterol (TC), triglycerides (TG), low-density lipoprotein (LDL-C), and high-density lipoprotein (HDL-C). These parameters were quantified at baseline and at 6, 12, 18, 24, 36, 48, 60, and 72 months after endocrine therapy initiation. Furthermore, a subgroup analysis according to menopausal status or medication types was conducted. RESULTS: A total of 1201 patients taking aromatase inhibitors (AIs), including anastrozole (ANA), letrozole (LET), or exemestane (EXE), and 1555 patients taking toremifene (TOR) were enrolled. TC and TG levels showed a significantly elevated trend during 5 years of treatment (P < 0.05). HDL-C levels increased from baseline in the TOR group (P < 0.05). Compared with the postmenopausal AI group, the increasing trends of TC, TG, and LDL-C in the premenopausal AI group were more evident with the extension of time (ß = 0.105, 0.027, 0.086, respectively). Within 3 years, TC, TG, and LDL-C levels in the ANA and LET groups were significantly higher than baseline (P < 0.05). Moreover, the levels of TG in the EXE group were significantly lower than that in the ANA or LET group (P < 0.05), but this significant difference disappeared after 3 years. CONCLUSIONS: AIs significantly influenced lipid profiles more than TOR. AIs had a greater effect on blood lipids in premenopausal patients. Steroidal AIs (EXE) may affect lipid levels less than nonsteroidal AIs (ANA and LET).

Quantum biochemical analysis of the binding interactions between a potential inhibitory drug and the Ebola viral glycoprotein.

Ebola virus disease (EVD) causes outbreaks and epidemics in West Africa that persist until today. The envelope glycoprotein of Ebola virus (GP) consists of two subunits, GP1 and GP2, and plays a key role in anchoring or fusing the virus to the host cell in its active form on the virion surface. Toremifene (TOR) is a ligand that mainly acts as an estrogen receptor antagonist; however, a recent study showed a strong and efficient interaction with GP. In this context, we aimed to evaluate the energetic affinity features involved in the interaction between GP and toremifene by computer simulation techniques using the Molecular Fractionation Method with Conjugate Caps (MFCC) scheme and quantum-mechanical (QM) calculations, as well as missense mutations to assess protein stability. We identified ASP522, GLU100, TYR517, THR519, LEU186, LEU515 as the most attractive residues in the EBOV glycoprotein structure that form the binding pocket. We divided toremifene into three regions and evaluated that region i was more important than region iii and region ii for the formation of the TOR-GP1/GP2 complex, which might control the molecular remodeling process of TOR. The mutations that caused more destabilization were ARG134, LEU515, TYR517 and ARG559, while those that caused stabilization were GLU523 and ASP522. TYR517 is a critical residue for the binding of TOR, and is highly conserved among EBOV species. Our results may help to elucidate the mechanism of drug action on the GP protein of the Ebola virus and subsequently develop new pharmacological approaches against EVD.Communicated by Ramaswamy H. Sarma.

Toremifene, an Alternative Adjuvant Endocrine Therapy, Is Better Than Tamoxifen in Breast Cancer Patients with CYP2D6*10 Mutant Genotypes.

PURPOSE: Tamoxifen showed individual differences in efficacy under different CYP2D6*10 genotypes. Our study evaluated the prognosis of tamoxifen or toremifene in hormone receptor (HR)-positive breast cancer patients under different genotypes. MATERIALS AND METHODS: CYP2D6*10 genotypes of HR-positive breast cancer patients were determined by Sanger sequencing, and all the patients were divided into tamoxifen group or toremifene group. RESULTS: A total of 268 patients with HR-positive breast cancer were studied. The median follow-up time was 72.0 months (range, 5.0 to 88.0 months). Of these, 88 (32.9%), 114 (42.5%), and 66 (24.6%) patients had C/C, C/T, and T/T genotypes, respectively. Among patients who received tamoxifen (n=176), the 5-year disease-free survival (DFS) rate in patients with C/C and C/T genotype was better than that in patients with T/T genotype, and the difference was statistically significant (p < 0.001 and p=0.030, respectively). In patients receiving toremifene, CYP2D6*10 genotype was not significantly associated with DFS (p=0.325). Regardless of genotypes, the 5-year DFS rate was higher in patients treated with toremifene than in patients with tamoxifen (91.3% vs. 80.0%, p=0.011). Compared with tamoxifen, toremifene remained an independent prognostic marker of DFS in multivariate analysis (hazard ratio, 0.422; p=0.021). For all the 180 patients with CYP2D6*10 C/T and T/T genotypes, the 5-year DFS rate was significantly higher in the toremifene group than in the tamoxifen group (90.8% vs. 70.1%, p=0.003). CONCLUSION: Toremifene may be an alternative adjuvant endocrine therapy for patients with CYP2D6*10 mutant genotypes.

Endometrial Adenofibroma in a Patient Receiving Toremifene: A Case Report

INTRODUCTION: Adenofibroma is a rare benign Müllerian mixed tumor composed of epithelial and mesenchymal cells. This tumor may occasionally be associated with toremifene therapy which is used as an adjuvant drug for breast cancer. CASE PRESENTATION: We describe a case of a 55-year-old woman with adenofibroma of the endometrium. This patient was receiving toremifene after surgery and neoadjuvant chemotherapy for breast cancer. She underwent a total abdominal hysterectomy and bilateral salpingectomy. There was no evidence of tumor residual or recurrence at 32 months of MRI follow-up. CONCLUSION: In conclusion, we report a rare case of endometrial adenofibroma in a patient receiving toremifene. It must be borne in mind that long-term toremifene therapy may increase the frequency of endometrial neoplasms.

The adverse effect of anticancer drug toremifene on vascular smooth muscle cells is an important aspect of its tumor growth inhibition.

PURPOSE: Toremifene (TOR) is widely used as an antineoplastic drug and has an inhibitory effect on angiogenesis in mesenteric desmoid tumors and vascular intracranial solitary fibrous tumors. However, no study has investigated the direct effect of TOR on vascular cells. This study aimed at exploring the effect of TOR on the behaviors of vascular smooth muscle cells (VSMCs). METHODS: Human aortic umbilical vascular smooth muscle cells (HAVSMCs) were treated by TOR. Cell morphology, migration, adhesion, and proliferation assay were investigated. The cell cycle, apoptosis, mitochondrial membrane potential, and reactive oxygen species were assessed using flow cytometry. Caspase-3 and 9 activities were assayed using Caspase-3 and Caspase-9 Activity Assay kits, respectively. Immunofluorescence and Western blot assays were carried out to characterize protein expressions of PCNA, p53, and Rho/ROCK signaling pathway. RESULTS: TOR damaged cytoskeleton, inhibited VSMC proliferation, migration, and adhesion, and induced abnormal cell morphology and apoptosis. The antiproliferative activity of TOR was associated with the induction of G0/G1 phase arrest, blocking the cell cycle. TOR disrupted intracellular reactive oxygen species and mitochondrial membrane potential, and enhanced p53 expression and the activities of caspase-3 and caspase-9. Thus, TOR-induced apoptosis by the mitochondrial signaling pathway. Additionally, TOR induced decreased Rho, ROCK, MLC, and pMLC proteins. Collectively, TOR may affect multiple behaviors of VSMCs by damaging cytoskeleton through the Rho/ROCK pathway. CONCLUSION: The adverse effect of TOR on VSMCs could be considered as an important aspect of tumor growth inhibition.

Concomitant administration of warfarin and toremifene: A case report.

WHAT IS KNOWN AND OBJECTIVE: Antiestrogen agents have been reported to enhance the anticoagulant activity of warfarin. The use of tamoxifen with warfarin has been contraindicated. However, warfarin in combination with toremifene has not been reported. We report a case in which warfarin was combined with toremifene and applied warfarin dose prediction models to predict the dose of warfarin. CASE SUMMARY: We report the case of a 50-year-old woman with a history of breast cancer, who underwent long-term toremifene therapy after mastectomy. The patient was treated with warfarin after prosthetic valve replacement and had a fluctuating international normalized ratio (INR) following the concomitant administration of toremifene. We applied the warfarin dose prediction model to adjust the warfarin dose during treatment. Finally, her INR stabilized with a lower dose of warfarin, and there was no serious bleeding during the 1-year follow-up. WHAT IS NEW AND CONCLUSION: Warfarin does not have a serious interaction with toremifene in this case, but it needed about 37.5% dose reduction which was comparable to the interaction of some common antibiotics with warfarin.

Comparison of adverse drug reactions between tamoxifen and toremifene in breast cancer patients with different CYP2D6 genotypes: A propensity-score matched cohort study.

CYP2D6 gene polymorphism has a profound impact upon the effect of tamoxifen as adjuvant endocrine therapy in breast cancer. However, it had never been reported whether the adverse drug reactions vary by CYP2D6 metabolic status for patients treated with tamoxifen or toremifene. We conducted a retrospective study in breast cancer patients to investigate the impact of CYP2D6 metabolic status on liver dysfunction events, gynecological events and dyslipidemia events. According to CYP2D6*10 (100C → T) genotype, the enrolled patients were further categorized into four cohorts (extensive metabolizers taking tamoxifen [EM + TAM], extensive metabolizers taking toremifene [EM + TOR], intermediate metabolizers taking tamoxifen [IM + TAM], and intermediate metabolizers taking toremifene [IM + TOR]). A total of 192 patients were included in the study, with a median follow-up time of 26.2 months. In EM + TAM cohort, the risks of liver dysfunction events (P = .004) and gynecological events (P = .004) were significantly higher compared to EM + TOR cohort. In IM + TAM cohort, the risks of liver dysfunction events (P = .14) and gynecological events (P = .99) were not significantly different from IM + TOR cohort. A significant decrease of total cholesterol was observed in EM + TAM cohort around 1 year after taking tamoxifen (P < .001). Significant interactions between CYP2D6 metabolic status and endocrine agents were observed in terms of liver dysfunction events (P-interaction = .007) and gynecological events (P-interaction = .026). These findings suggested that CYP2D6 gene polymorphism played a significant role in predicting liver dysfunction, gynecological diseases and lipid metabolism changes among patients taking tamoxifen or toremifene.

Chinese breast cancer patients with CYP2D6*10 mutant genotypes have a better prognosis with toremifene than with tamoxifen.

PURPOSE: To evaluate the prognosis of estrogen receptor-positive breast cancer patients with CYP2D6*10 mutant genotypes under tamoxifen or toremifen therapy. METHODS: Estrogen receptor-positive breast cancer patients were selected and CYP2D6*10 genotypes (C/C, C/T, and T/T) were determined by Sanger sequencing. Patients were divided into tamoxifen, toremifene, or tamoxifen + toremifene groups according to prior therapy. The correlation between CYP2D6*10 genotype and disease-free survival was analyzed. RESULTS: In total, 293 estrogen receptor-positive breast cancer patients treated with tamoxifen or toremifene between 2008 and 2017 were studied. Median follow-up was 39 months (10-141). Of these, 107 (36.52%), 112 (38.23%), and 74 (25.26%) patients had C/C, C/T, and T/T genotypes, respectively. Genotype was significantly associated with disease-free survival in tamoxifen patients. Patients with C/T and T/T genotypes showed worse disease-free survival than patients with a C/C genotype. Genotype and disease-free survival in toremifene and tamoxifen+toremifene patients were not correlated. Of patients with a C/T genotype, toremifene or tamoxifen+toremifene groups showed better disease-free survival than tamoxifen patients. Although disease-free survival of patients with a T/T genotype in the three groups was not statistically different, tamoxifen patients showed worse disease-free survival. There was no correlation between different treatments and disease-free survival in patients with a C/C genotype. Cox proportional hazard analysis revealed toremifene patients had a better prognosis than tamoxifen patients; toremifene was an independent protective factoremifene for disease-free survival. CONCLUSIONS: Tamoxifen was less effective in patients with CYP2D6*10 C/T and T/T genotypes. Estrogen receptor-positive breast cancer patients with a CYP2D6*10 mutation genotype have a better prognosis with toremifen than tamoxifen.

Effects of Tamoxifen vs. Toremifene on fatty liver development and lipid profiles in breast Cancer.

BACKGROUND: Tamoxifen (TAM) and Toremifene (TOR), two kinds of selective estrogen receptor modulators (SERMs), have equal efficacy in breast cancer patients. However, TAM has been proved to affect serum lipid profiles and cause fatty liver disease. The study aimed to compare the effects of TAM and TOR on fatty liver development and lipid profiles. METHODS: This study performed a retrospective analysis of 308 SERMs-treated early breast cancer patients who were matched 1:1 based on propensity scores. The follow-up period was 3 years. The primary outcomes were fatty liver detected by ultrasonography or computed tomography (CT), variation in fibrosis indexes, and serum lipid profiles change. RESULTS: The cumulative incidence rate of new-onset fatty liver was higher in the TAM group than in the TOR group (113.2 vs. 67.2 per 1000 person-years, p < 0.001), and more severe fatty livers occurred in the TAM group (25.5 vs. 7.5 per 1000 person-years, p = 0.003). According to the Kaplan-Meier curves, TAM significantly increased the risk of new-onset fatty liver (25.97% vs. 17.53%, p = 0.0243) and the severe fatty liver (5.84% vs. 1.95%, p = 0.0429). TOR decreased the risk of new-onset fatty liver by 45% (hazard ratio = 0.55, p = 0.020) and showed lower fibrotic burden, independent of obesity, lipid, and liver enzyme levels. TOR increased triglycerides less than TAM, and TOR increased high-density lipoprotein cholesterol, while TAM did the opposite. No significant differences in total cholesterol and low-density lipoprotein cholesterol are observed between the two groups. CONCLUSIONS: TAM treatment is significantly associated with more severe fatty liver disease and liver fibrosis, while TOR is associated with an overall improvement in lipid profiles, which supports continuous monitoring of liver imaging and serum lipid levels during SERM treatment.

Selective estrogen receptor modulators (SERMs) affect cholesterol homeostasis through the master regulators SREBP and LXR.

Selective estrogen receptor modulators (SERMs) are nonsteroidal drugs that display an estrogen-agonist or estrogen-antagonist effect depending on the tissue targeted. SERMs have attracted great clinical interest for the treatment of several pathologies, most notably breast cancer and osteoporosis. There is strong evidence that SERMs secondarily affect cholesterol metabolism, although the mechanism has not been fully elucidated. In this study, we analysed the effect of the SERMs tamoxifen, raloxifene, and toremifene on the expression of lipid metabolism genes by microarrays and quantitative PCR in different cell types, and ascertained the main mechanisms involved. The three SERMs increased the expression of sterol regulatory element-binding protein (SREBP) target genes, especially those targeted by SREBP-2. In consonance, SERMs increased SREBP-2 processing. These effects were associated to the interference with intracellular LDL-derived cholesterol trafficking. When the cells were exposed to LDL, but not to cholesterol/methyl-cyclodextrin complexes, the SERM-induced increases in gene expression were synergistic with those induced by lovastatin. Furthermore, the SERMs reduced the stimulation of the transcriptional activity of the liver X receptor (LXR) by exogenous cholesterol. However, their impact on the expression of the LXR canonical target ABCA1 in the presence of LDL was cell-type dependent. These actions of SERMs were independent of estrogen receptors. We conclude that, by inhibiting the intracellular trafficking of LDL-derived cholesterol, SERMs promote the activation of SREBP-2 and prevent the activation of LXR, two master regulators of cellular cholesterol metabolism. This study highlights the impact of SERMs on lipid homeostasis regulation beyond their actions as estrogen receptor modulators.

Formulation, Stability, Pharmacokinetic, and Modeling Studies for Tests of Synergistic Combinations of Orally Available Approved Drugs against Ebola Virus In Vivo.

Outbreaks of Ebola ebolavirus (EBOV) have been associated with high morbidity and mortality. Milestones have been reached recently in the management of EBOV disease (EVD) with licensure of an EBOV vaccine and two monoclonal antibody therapies. However, neither vaccines nor therapies are available for other disease-causing filoviruses. In preparation for such outbreaks, and for more facile and cost-effective management of EVD, we seek a cocktail containing orally available and room temperature stable drugs with strong activity against multiple filoviruses. We previously showed that (bepridil + sertraline) and (sertraline + toremifene) synergistically suppress EBOV in cell cultures. Here, we describe steps towards testing these combinations in a mouse model of EVD. We identified a vehicle suitable for oral delivery of the component drugs and determined that, thus formulated the drugs are equally active against EBOV as preparations in DMSO, and they maintain activity upon storage in solution for up to seven days. Pharmacokinetic (PK) studies indicated that the drugs in the oral delivery vehicle are well tolerated in mice at the highest doses tested. Collectively the data support advancement of these combinations to tests for synergy in a mouse model of EVD. Moreover, mathematical modeling based on human oral PK projects that the combinations would be more active in humans than their component single drugs.

Effect of Toremifene on Endometrium and Neurocognitive Function in Patients with Breast Cancer Based on Resting-State Functional Magnetic Resonance Imaging.

In this study, the characteristics of hemodynamic changes with use of toremifene before and after neoadjuvant chemotherapy in breast cancer treatment were analyzed using resting-state functional magnetic resonance imaging. Also, the effect of toremifene on the quality of life of patients with advanced breast cancer was analyzed. The study population comprised 100 patients who received endocrine therapy after breast cancer surgery in our hospital from January 2016 to January 2019. Patients were randomly divided into an observation group and a control group, with 50 cases in each group. The observation group was treated with tamoxifen combined with toremifene treatment; the control group was treated with toremifene. Before and after chemotherapy, the same scheme was used to perform dynamic contrast-enhanced imaging of the breast using a 1.5T superconducting scanner with 3 mL/second bolus injection of adiphenine meglumine 0.2 mmol/kg. Semiquantitative blood flow measurement was completed on the workstation and before and after chemotherapy to compare results. The patient's quality of life, progesterone and estrogen levels, social function, physical function, mental function, and material function were analyzed. The mean values of the early enhancement parameters Efirst, Vfirst, Ee, and Ve before chemotherapy were greater than in the residual lesions after chemotherapy (P < 0.5). The semiquantitative study of resting brain function before and after breast cancer neoadjuvant chemotherapy showed that the hemodynamics of the residual lesions were significantly reduced, and the blood flow rate was significantly reduced. Compared with the clinical effect of tamoxifen in the treatment of breast cancer after surgery, tamoxifen combined with toremifene has more advantages in improving quality of life, improving progesterone levels, and reducing estrogen levels, and it has no detrimental effects on the endometrium.

Repurposing of FDA-Approved Toremifene to Treat COVID-19 by Blocking the Spike Glycoprotein and NSP14 of SARS-CoV-2.

The global pandemic of Coronavirus Disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has led to the death of more than 675,000 worldwide and over 150,000 in the United States alone. However, there are currently no approved effective pharmacotherapies for COVID-19. Here, we combine homology modeling, molecular docking, molecular dynamics simulation, and binding affinity calculations to determine potential targets for toremifene, a selective estrogen receptor modulator which we have previously identified as a SARS-CoV-2 inhibitor. Our results indicate the possibility of inhibition of the spike glycoprotein by toremifene, responsible for aiding in fusion of the viral membrane with the cell membrane, via a perturbation to the fusion core. An interaction between the dimethylamine end of toremifene and residues Q954 and N955 in heptad repeat 1 (HR1) perturbs the structure, causing a shift from what is normally a long, helical region to short helices connected by unstructured regions. Additionally, we found a strong interaction between toremifene and the methyltransferase nonstructural protein (NSP) 14, which could be inhibitory to viral replication via its active site. These results suggest potential structural mechanisms for toremifene by blocking the spike protein and NSP14 of SARS-CoV-2, offering a drug candidate for COVID-19.

A prospective, randomized study of Toremifene vs. tamoxifen for the treatment of premenopausal breast cancer: safety and genital symptom analysis.

BACKGROUND: Toremifene (TOR) is a selective oestrogen receptor modulator (SERM) and has comparable efficacy to that of tamoxifen (TAM) in breast cancer patients. Herein, we compared the safety of TOR to that of TAM in the adjuvant treatment of premenopausal breast cancer. METHODS: This was a prospective randomized and open-label clinical study. Premenopausal patients with hormonal receptor (HR)-positive early breast cancer were randomly assigned (1:1) to receive TOR) or TAM treatment. The follow-up period was 1 year. The primary end point was the incidence of ovarian cysts, and secondary end points were the incidence of endometrial thickening, changes in female hormones, the incidence of fatty liver, changes in the modified Kupperman index (mKMI) and changes in quality of life. RESULTS: There were 92 patients in the final analysis. The incidences of ovarian cysts were 42.6% in the TOR group and 51.1% in the TAM group (p = 0.441). Forty-one patients (87.2%) in the TOR group and 36 patients (80.0%) in the TAM group experienced endometrial thickening (p = 0.348). The proportions of patients with fatty liver were 31.9% in the TOR group and 26.7% in the TAM group (p = 0.581). No significant differences in the mKMI or quality of life were observed between the two groups. CONCLUSIONS: TOR and TAM have similar side effects on the female genital system and quality of life in premenopausal early breast cancer patients. TRIAL REGISTRATION: ClinicalTrials.gov NCT02344940. Registered 26 January 2015 (retrospectively registered).

Prediction of drug dissolution from Toremifene 80 mg tablets by NIR spectroscopy.

The aim of our study was to justify substitution of dissolution analysis for NIR measurement of Toremifene 80 mg tablets. We studied implementation of a NIRS method by integrating the method development to discrimination power of the dissolution method. Hence, we analyzed 20 DoE tablet batches and studied which of the critical formulation factors affecting dissolution were statistically significant. To study if these factors can be detected by NIRS, PLS calibration models were developed. Finally, PLS model was built to correlate NIR data with the actual dissolution results to predict the released amount of toremifene in 30 min. To obtain the data the tablet batches were measured by NIR using diffuse reflectance technique and multivariate analysis tool was used to calibrate the NIRS models. Correlations between the critical formulation factors and the NIR spectra of Toremifene 80 mg tablet were shown and it was thus justified to develop a NIRS prediction model for dissolution. Variance (R2), standard error of estimate (SEE) and standard error of prediction (SEP) of the model were 90.0%, 4.3% and 5.9%, respectively. It was thus shown that multi-phased and time consuming dissolution procedure could be substituted for fast non-invasive NIRS method.

Pharmacogenomic-pharmacokinetic study of selective estrogen-receptor modulators with intra-patient dose escalation in breast cancer.

BACKGROUND: An association between CYP2D6 polymorphisms and tamoxifen (TAM) efficacy has not been confirmed, partly due to unreliable prediction of active metabolite exposure solely by CYP2D6 activity. The efficacy of TAM dose escalation appears limited in poor TAM metabolizers. Since the chlorine atom on the side chain of toremifene (TOR) prevents 4-hydroxylation by CYP2D6, its contribution to active conversion of TOR is minor. We examined the role of TOR and its dose escalation among poor TAM metabolizers. METHODS: The pharmacokinetics (PK) and pharmacogenomics (PGx) of TAM and TOR were studied. Correlation between PK and CYP2D6 inhibitor use, smoking status, and PGx were examined by regression analysis. For patients showing low endoxifen levels, an intra-patient dose escalation of TOR was conducted, and TOR was increased from 40 to 120 mg for ≥ 24 weeks with PK sampling. Total activity was calculated as the sum of the concentration of each active metabolite adjusted by their respective in vitro activities. RESULTS: Fifty and 11 of the 273 participating patients had endoxifen levels < 15 and < 7.5 ng/mL, respectively. The CYP2D6 genotype was the major determinant for TAM activity (p < 0.01). Smoking status (p = 0.07) and the CYP2C19 phenotype (p = 0.07), but not the CYP2D6 genotype (p = 0.61), showed marginally significant effects on TOR activity. TOR activity increased significantly with dose escalation, even among poor TAM metabolizers, and was maintained for ≥ 24 weeks. CONCLUSION: TOR might be a valid alternative to TAM in patients predicted to be poor TAM metabolizers.

The use of selective estrogen receptor modulators on bone health in men.

Selective estrogen receptor modulators (SERMs) represent a class of drugs that act as agonist or antagonist for estrogen receptor in a tissue-specific manner. The SERMs drugs are initially used for the prevention and treatment of osteoporosis in postmenopausal women. Bone health in prostate cancer patients has become a significant concern, whereby patients undergo androgen deprivation therapy is often associated with deleterious effects on bone. Previous preclinical and epidemiological findings showed that estrogens play a dominant role in improving bone health as compared to testosterone in men. Therefore, this evidence-based review aims to assess the available evidence derived from animal and human studies on the effects of SERMs on the male skeletal system. The effects of SERMs on bone mineral density (BMD)/content (BMC), bone histomorphometry, bone turnover, bone strength and fracture risk have been summarized in this review.