Discovery and Preclinical Pharmacology of NX-2127, an Orally Bioavailable Degrader of Bruton's Tyrosine Kinase with Immunomodulatory Activity for the Treatment of Patients with B Cell Malignancies

Bruton's tyrosine kinase (BTK), a member of the TEC family of kinases, is an essential effector of B-cell receptor (BCR) signaling. Chronic activation of BTK-mediated BCR signaling is a hallmark of many hematological malignancies, which makes it an attractive therapeutic target. Pharmacological inhibition of BTK enzymatic function is now a well-proven strategy for the treatment of patients with these malignancies. We report the discovery and characterization of NX-2127, a BTK degrader with concomitant immunomodulatory activity. By design, NX-2127 mediates the degradation of transcription factors IKZF1 and IKZF3 through molecular glue interactions with the cereblon E3 ubiquitin ligase complex. NX-2127 degrades common BTK resistance mutants, including BTKC481S. NX-2127 is orally bioavailable, exhibits in vivo degradation across species, and demonstrates efficacy in preclinical oncology models. NX-2127 has advanced into first-in-human clinical trials and achieves deep and sustained degradation of BTK following daily oral dosing at 100 mg.

Tralesinidase alfa enzyme replacement therapy prevents disease manifestations in a canine model of mucopolysaccharidosis type IIIB

Mucopolysaccharidosis type IIIB (MPS IIIB; Sanfilippo syndrome B; OMIM #252920) is a lethal, pediatric, neuropathic, autosomal recessive, and lysosomal storage disease with no approved therapy. Patients are deficient in the activity of N-acetyl-alpha-glucosaminidase (NAGLU; EC 3.2.150), necessary for normal lysosomal degradation of the glycosaminoglycan heparan sulfate (HS). Tralesinidase alfa (TA), a fusion protein comprised of recombinant human NAGLU and a modified human insulin-like growth factor 2, is in development as an enzyme replacement therapy that is administered via intracerebroventricular (ICV) infusion, thus circumventing the blood brain barrier. Previous studies have confirmed ICV infusion results in widespread distribution of TA throughout the brains of mice and nonhuman primates. We assessed the long-term tolerability, pharmacology, and clinical efficacy of TA in a canine model of MPS IIIB over a 20-month study. Long-term administration of TA was well tolerated as compared with administration of vehicle. TA was widely distributed across brain regions, which was confirmed in a follow-up 8-week pharmacokinetic/pharmacodynamic study. MPS IIIB dogs treated for up to 20 months had near-normal levels of HS and nonreducing ends of HS in cerebrospinal fluid and central nervous system (CNS) tissues. TA-treated MPS IIIB dogs performed better on cognitive tests and had improved CNS pathology and decreased cerebellar volume loss relative to vehicle-treated MPS IIIB dogs. These findings demonstrate the ability of TA to prevent or limit the biochemical, pathologic, and cognitive manifestations of canine MPS IIIB disease, thus providing support of its potential long-term tolerability and efficacy in MPS IIIB subjects.

Ziritaxestat Drug-Drug Interaction with Oral Contraceptives: Role of SULT1E1 Inhibition

In vitro signals indicate that ziritaxestat is a weak cytochrome P450 (CYP) 3A4 inhibitor and inducer. Therefore, potential drug–drug interactions (DDIs) with oral contraceptives were examined at a time when ziritaxestat was under development for treatment of fibrotic diseases. This open‐label, crossover (fixed sequence) DDI study enrolled healthy, nonpregnant women aged 18–65 years (n = 15) who were using highly effective contraception, such as a nonhormonal intrauterine device, bilateral tubal occlusion, or sexual abstinence. A single dose of oral contraceptive (0.03 mg ethinyl estradiol (EE) and 3 mg drospirenone (DRSP)) was administered on days 1, 8, and 18, and ziritaxestat 600 mg once daily was administered from days 8 to 23. Co‐administration resulted in a 2.8‐fold and 2.4‐fold increase in EE maximum plasma concentration (C_max) and area under the plasma drug concentration–time curve from time zero to infinity (AUC_0–inf), respectively (day 18 vs. day 1). DRSP C_max and AUC_0–inf increased by 1.1‐fold and 1.2‐fold, respectively. DRSP is a CYP3A4 substrate, meaning increased EE exposure with ziritaxestat was not due to CYP3A4 inhibition. Ziritaxestat inhibition of EE glucuronidation and sulfation was quantified by liquid chromatography with tandem mass spectrometry in day 1 and day 18 plasma samples after EE conjugate hydrolysis. The ratio of EE AUC from time of administration up to the time of the last quantifiable concentration (AUC_last) with/without hydrolysis by arylsulfatase was substantially lower on day 18 vs. day 1, suggesting ziritaxestat is a potent inhibitor of sulfation; EE glucuronidation was largely unaffected by ziritaxestat. In vitro assessment confirmed ziritaxestat is a potent inhibitor of sulfotransferase family 1E member 1 (half‐maximal inhibitory concentration < 0.8 μM). These findings highlight the importance of assessing enzymes other than CYP3A4 when investigating potential DDIs with oral contraceptives.

Evaluation of the Potential for Pharmacokinetic Interaction Between Tirabrutinib and Levonorgestrel/Ethinyl Estradiol in Healthy Female Volunteers

Tirabrutinib (TIRA), a potent and nonreversible oral Bruton tyrosine kinase inhibitor, is evaluated for treatment of certain hematological malignancies and inflammatory diseases. A drug–drug interaction study to evaluate the effect of TIRA on the pharmacokinetics of the oral contraceptive levonorgestrel (LEVO)/ethinyl estradiol (EE) was conducted in healthy female participants (N = 26). Participants received a single dose of LEVO (150 mcg)/EE (30 mcg) alone (reference), and on day 12 of a 15‐day regimen of TIRA 160 mg once‐daily (test). Intensive blood sampling for determination of LEVO, EE, and TIRA plasma concentrations was conducted, and safety was assessed throughout the study. Pharmacokinetic interactions were evaluated using 90% confidence intervals (CIs) of the geometric least squares mean (GLSM) ratios of the test versus reference treatments. The GLSM (90% CI) ratios of area under the concentration‐time curve from zero to infinity (AUC_inf; LEVO: 0.95, 95% CI: 0.88–1.03, EE: 1.10, 95% CI: 1.05–1.16) and maximum plasma concentration (C_max; LEVO: 0.85, 95% CI: 0.74–0.98, EE: 1.07, 95% CI: 0.98–1.18) were within the prespecified 0.70 to 1.43 no effect bounds; and the AUC ratios met the stricter 0.80 to 1.25 equivalence bounds. Study treatments were generally well‐tolerated. In conclusion, co‐administration with TIRA did not alter the exposure of LEVO/EE, and accordingly LEVO/EE containing oral contraceptives can serve as a contraception method for participants on TIRA 160 mg (or lower) daily doses.

Inflammation Causes Resistance to Anti-CD20-Mediated B Cell Depletion

B cells play a central role in antibody-mediated rejection and certain autoimmune diseases. However, B cell-targeted therapy such as anti-CD20 B cell-depleting antibody (aCD20) has yielded mixed results in improving outcomes. In this study, we investigated whether an accelerated B cell reconstitution leading to aCD20 depletion resistance could account for these discrepancies. Using a transplantation model, we found that antigen-independent inflammation, likely through toll-like receptor (TLR) signaling, was sufficient to mitigate B cell depletion. Secondary lymphoid organs had a quicker recovery of B cells when compared to peripheral blood. Inflammation altered the pharmacokinetics (PK) and pharmacodynamics (PD) of aCD20 therapy by shortening drug half-life and accelerating the reconstitution of the peripheral B cell pool by bone marrow-derived B cell precursors. IVIG (intravenous immunoglobulin) coadministration also shortened aCD20 drug half-life and led to accelerated B cell recovery. Repeated aCD20 dosing restored B cell depletion and delayed allograft rejection, especially B cell-dependent, antibody-independent allograft rejection. These data demonstrate the importance of further clinical studies of the PK/PD of monoclonal antibody treatment in inflammatory conditions. The data also highlight the disconnect between B cell depletion on peripheral blood compared to secondary lymphoid organs, the deleterious effect of IVIG when given with aCD20 and the relevance of redosing of aCD20 for effective B cell depletion in alloimmunity.

Levonorgestrel butanoate intramuscular injection does not reliably suppress ovulation for 90 days in obese and normal-BMI women: a pilot study

BACKGROUND

We performed a pilot evaluation of a new formulation of levonorgestrel butanoate (LB) designed to be a long-acting injectable (6 months) contraceptive to determine pharmacodynamic end points in normal-body mass index (BMI) and obese women.

STUDY DESIGN

Obese (BMI ≥30 kg/m²) and normal-BMI, otherwise healthy, women received a single intramuscular injection of LB after ovulation was confirmed in a baseline cycle. The primary outcome was return of ovulation in days.

RESULTS

A total of 14 women enrolled and completed the study [normal BMI n=9, median BMI 22.7kg/m² (range 19.4-25.8); obese n=5, median BMI 35.7kg/m² (30.1-39.2)]. The first 6 subjects (normal BMI=4/9, obese BMI=2/5) received 40 mg of LB, and the remaining 8 received 20 mg. All women except one returned to ovulation prior to 6 months. Return to ovulation occurred earlier in the obese group; 3/5 obese and 0/9 normal BMI subjects returned to ovulation within 90 days (p=.03). No serious adverse events were reported during the study.

CONCLUSION

Return to ovulation was earlier than 6 months in both BMI groups but more so in the obese BMI group.

IMPLICATIONS

Since return of ovulation was earlier than expected for this LB injectable formulation, additional steps are needed to develop a preparation suitable as a longer-lasting product.

Furosemide Pharmacokinetics in Adult Rats become Abnormal with an Adverse Intrauterine Environment and Modulated by a Post-Weaning High-Fat Diet

Adult individuals born with intrauterine growth restriction (IUGR) have physiological maladaptations that significantly increase risk of chronic disease. We suggested that such abnormalities in organ function would alter pharmacokinetics throughout life, exacerbated by environmental mismatch. Pregnant and lactating rats were fed either a purified control diet (18% protein) or low-protein diet (9% protein) to produce IUGR offspring. Offspring were weaned onto either laboratory chow (11% fat) or high-fat diet (45% fat). Adult offspring (5 months old) were dosed with furosemide (10 mg/kg i.p.) and serum and urine collected. The overall exposure profile in IUGR males was significantly reduced due to a ~35% increase in both clearance and volume of distribution. Females appeared resistant to the IUGR phenotype. The effects of the high-fat diet trended in the opposite direction to that of IUGR, with increased drug exposure due to decreases in both clearance (31% males, 46% females) and volume of distribution (24% males, 44% females), with a 10% longer half-life in both genders. The alterations in furosemide pharmacokinetics and pharmacodynamics were explained by changes in the expression of renal organic anion transporters 1 and 3, and sodium-potassium-chloride cotransporter-2. In summary, this study suggests that IUGR and diet interact to produce subpopulations with similar body-weights but dissimilar pharmacokinetic profiles; this underlines the limitation of one-size-fits-all dosing which does not account for physiological differences in body composition resulting from IUGR and diet.

Theophylline Pharmacokinetics in Foetal Sheep: Maternal Metabolic Capacity is the Principal Driver

Understanding theophylline pharmacokinetics (PK) in the foetus is essential to prevent in utero toxicity and optimize prophylactic therapies. Previous studies in pregnancy have been obfuscated by maternal dosing and inadequate sampling in the foetus; both render modelling of foetal PK difficult. Six ewes carrying singleton foetuses received theophylline (60 mg) into the foetal jugular vein. Blood samples were drawn from the foetus and ewe over 36 hr. Serum concentrations were measured. Maternal and foetal pharmacokinetic parameters were estimated. Foetal non-compartmental pharmacokinetic parameters were as follows: half-life 7.37 ± 1.22 hr; volume of distribution 44.62 ± 11.45 L; area under the curve 14.82 ± 2.71 hr/(μg/mL); and clearance 4.15 ± 0.70 L/hr. Rapid theophylline distribution across the placenta was observed. Maternal non-compartmental pharmacokinetic parameters were as follows: half-life 6.54 ± 2.44 hr; volume of distribution 32.48 ± 9.99 L; area under the curve 16.28 ± 4.53 hr/(μg/mL); and clearance 3.69 ± 1.47 L/hr. Foetal and ewe serum concentration-time profiles were fit together into a 3-compartment population pharmacokinetic model, and parameters were as follows: central volume 1.38 ± 0.11 L; 2nd peripheral compartment volume 3.11 ± 0.29 L; 3rd peripheral compartment volume 60.14 ± 6.02 L; elimination clearance 9.89 ± 0.90 L/hr; distribution clearance between central and 2nd compartment 30.87 ± 2.31 L/hr; and distribution clearance between 2nd and 3rd compartments 13.89 ± 1.11 L/hr. Cytochrome P4501A expression was robust in maternal liver; negligible activities were observed in placenta, foetal liver and foetal kidney. In vitro protein binding of theophylline was 30% lower in foetal serum compared to maternal serum (29.7 ± 4.4 versus 42.0 ± 3.6%-bound). Free concentrations were lower in the foetus than in the ewe, suggesting active transport across placenta. In summary, foetal clearance of theophylline is attributable to rapid distribution into the maternal circulation across the placenta followed by greater maternal protein binding and metabolic activity.

A phase II study of sulforaphane-rich broccoli sprout extracts in men with recurrent prostate cancer

INTRODUCTION

Diets high in cruciferous vegetables are associated with lower risk of incidence of prostate cancer, including aggressive forms of this disease. Human intervention studies with cruciferous vegetable-rich diets also demonstrate modulation of gene expression in important pathways in prostate cells.

PURPOSE

Sulforaphane is a constituent of these foods postulated to harbor the anti-neoplastic activity based on multiple tumor models. Our own work demonstrates that sulforaphane inhibits AR signaling in prostate cancer cells. Here, we report results from the first clinical trial of sulforaphane-rich extracts in men with prostate cancer.

METHODS

We treated 20 patients who had recurrent prostate cancer with 200 μmoles/day of sulforaphane-rich extracts for a maximum period of 20 weeks and determined the proportion of patients with ≥50% PSA declines, the primary endpoint. Only one subject experienced a ≥50% PSA decline. Thus, the primary endpoint was not achieved. Seven patients experienced smaller PSA declines (<50%). There was also a significant lengthening of the on-treatment PSA doubling time (PSADT) compared with the pre-treatment PSADT [6.1 months pre-treatment vs. 9.6 months on-treatment (p = 0.044)]. Finally, treatment with sulforaphane-rich extracts was safe with no Grade 3 adverse events.

CONCLUSIONS

Treatment with 200 μmoles/day of sulforaphane-rich extracts did not lead to ≥50% PSA declines in the majority of patients. However, because of the safety of treatment and the effects on PSADT modulation, further studies, including those with higher doses, may be warranted to clarify the role of sulforaphane as a prevention agent or treatment agent.

How can we improve oral contraceptive success in obese women?

A rapid increase in obesity rates worldwide further underscores the importance of better understanding the pharmacokinetic alterations in this sub-population and the subsequent effects on pharmacotherapeutics. Pharmacokinetics of contraceptive steroids is altered in obese oral contraceptive users, which may in turn impact efficacy. Our study has identified several dosing strategies that offset these pharmacokinetic changes and may improve effectiveness for obese oral contraception users.

Increased exposure of norethindrone in HIV+ women treated with ritonavir-boosted atazanavir therapy

OBJECTIVE

Pharmacokinetics of norethindrone in combination oral contraceptive regimen are well described among HIV+ women treated with ritonavir-boosted protease inhibitor therapies; however, such characterization is lacking in women using progestin-only contraception. Our objective is to characterize pharmacokinetics of norethindrone in HIV+ women using ritonavir-boosted atazanavir treatment during progestin-only contraceptive regimens.

STUDY DESIGN

An open-label, prospective, nonrandomized trial to characterize the pharmacokinetics of norethindrone in HIV+ women receiving ritonavir-boosted atazanavir (n=10; treatment group) and other antiretroviral therapy known to not alter norethindrone levels (n=17; control group) was conducted. Following informed consent, women were instructed to take a single daily fixed oral dose of 0.35 mg norethindrone and 300 mg/100 mg atazanavir/ritonavir for 22 days. On day 22, serial blood samples were collected by venous catheter at 0, 1, 2, 3, 4, 6, 8, 12, 24, 48 and 72 h. Whole blood was processed to collect serum and stored at -20°C until later analysis using radioimmunoassay. Pharmacokinetic parameters were estimated using noncompartmental method.

RESULTS

In the treatment group, compared to the control group, an increase in area under the curve₀₋₂₄ (16.69 h*ng/mL vs. 25.20 h*ng/mL; p<.05) and maximum serum concentration (2.09 ng/mL vs. 3.19 ng/mL; p<.05), decrease (25%-40%) in apparent volume of distribution and apparent clearance, and unaltered half-life were observed.

CONCLUSION(S)

Our findings suggest that progestin-only contraceptives, unlike combination oral contraceptives, benefit from drug-drug interaction and achieve higher levels of exposure. Further studies are needed to establish whether pharmacokinetic interaction leads to favorable clinical outcomes.

IMPLICATIONS

Norethindrone-based progestin-only contraceptives, unlike combination oral contraceptives, exhibit greater drug exposure when co-administered with ritonavir-boosted atazanavir regimen and thus may not warrant a category 3 designation by the World Health Organization. Prospective studies are needed to confirm whether pharmacokinetic interaction results in favorable clinical outcomes.

Correcting oral contraceptive pharmacokinetic alterations due to obesity: a randomized controlled trial

OBJECTIVE

To determine if increasing the hormone dose or eliminating the hormone-free interval improves key pharmacokinetic (PK) alterations caused by obesity during oral contraceptive (OC) use.

STUDY DESIGN

Obese [body mass index (BMI)≥30 kg/m(2)], ovulatory, otherwise healthy, women received an OC containing 20 mcg ethinyl estradiol (EE)/100 mcg levonorgestrel (LNG) dosed cyclically (21 days active pills with 7-day placebo week) for two cycles and then were randomized for two additional cycles to the following: continuous cycling (CC, a dose neutral arm using the same OC with no hormone-free interval) or increased dose (ID, a dose escalation arm using an OC containing 30 mcg EE/150 mcg LNG cyclically). During Cycles 2, 3 and 4, outpatient visits were performed to assess maximum serum concentration (Cmax), area under the curve (AUC0-∞) and time to steady state as well as pharmacodynamics. These key PK parameters were calculated and compared within groups between baseline and treatment cycles.

RESULTS

A total of 31 women enrolled and completed the study (CC group, n=16; ID group, n=15). Demographics were similar between groups [mean BMI: CC, 38 kg/m(2) (S.D. 5.1); ID, 41 kg/m(2) (S.D. 7.6)]. At baseline, the key LNG PK parameters were no different between groups; average time to reach steady state was 12 days in both groups; Cmax were CC: 3.82±1.28 ng/mL and ID: 3.13±0.87 ng/mL; and AUC0-∞ were CC: 267±115 h ng/mL and ID: 199±75 h ng/mL. Following randomization, the CC group maintained steady-state serum levels whereas the ID group had a significantly higher Cmax (p<.001) but again required 12 days to achieve steady state. However, AUC was not significantly different between CC (412±255 h ng/mL) and ID (283±130 h ng/mL). Forty-five percent (14/31) of the study population had evidence of an active follicle-like structure prior to randomization and afterwards this decreased to 9% (3/31).

CONCLUSION

Both increasing the OC dose and continuous dosing appear to counteract the impact of obesity on key OC PK parameters.

IMPLICATIONS

Obesity adversely affects the pharmacokinetics of very low dose OC pills. Although the impact of these changes on OC efficacy is still under debate, PK parameters can be normalized in obese users by continuous dosing or increasing to a low-dose pill.

Perinatal growth restriction decreases diuretic action of furosemide in adult rats

Perinatal growth restriction programs higher risk for chronic disease during adulthood via morphological and physiological changes in organ systems. Perinatal growth restriction is highly correlated with a decreased nephron number, altered renal function and subsequent hypertension. We hypothesize that such renal maladaptations result in altered pharmacologic patterns for life. Maternal protein restriction during gestation and lactation was used to induce perinatal growth restriction in the current study. The diuretic response of furosemide (2mg/kg single i.p. dose) in perinatally growth restricted rats during adulthood was investigated. Diuresis, natriuresis and renal excretion of furosemide were significantly reduced relative to controls, indicative of decreased efficacy. While a modest 12% decrease in diuresis was observed in males, females experienced 26% reduction. It is important to note that the baseline urine output and natriuresis were similar between treatment groups. The in vitro renal and hepatic metabolism of furosemide, the in vivo urinary excretion of the metabolite, and the expression of renal drug transporters were unaltered. Creatinine clearance was significantly reduced by 15% and 19% in perinatally growth restricted male and female rats, respectively. Further evidence of renal insufficiency was suggested by decreased uric acid clearance. Renal protein expression of sodium-potassium-chloride cotransporter, a pharmacodynamic target, was unaltered. In summary, perinatal growth restriction could permanently imprint pharmacokinetic processes affecting drug response.

Clopidogrel variability: role of plasma protein binding alterations

AIM

The large inter-individual variability in clopidogrel response is attributed to pharmacokinetics. Although, it has been used since the late 1990s the pharmacokinetic fate of clopidogrel and its metabolites are poorly explained. The variable response to clopidogrel is believed to be multi-factorial, caused both by genetic and non-genetic factors. In this study, we examined whether the inactive metabolite can alter the plasma protein binding of the active metabolite, thus explaining the large inter-individual variability associated with clopidogrel response.

METHODS

Female subjects (n = 28) with stable coronary disease who were not taking clopidogrel were recruited. Serial blood samples were collected following 300 mg oral dose of clopidogrel, plasma was isolated and quantified for total and free concentrations of active and inactive metabolites. Inhibition of platelet aggregation was measured using the phosphorylated vasodilator stimulated phosphoprotein (VASP) assay.

RESULTS

A significant correlation was observed between VASP and both free (r = 0.49, P < 0.05) and total (r = 0.49, P < 0.05) concentrations of the active metabolite. Surprisingly, we observed a significant correlation with both free (r = 0.42, P < 0.05) and total (r = 0.67, P < 0.001) concentrations of the inactive metabolite as well. Free fractions of the active metabolite rose with increasing protein binding of the inactive metabolite (P < 0.05).

CONCLUSIONS

The above in vivo data suggest that the inactive metabolite displaces the active metabolite from binding sites. Thus, the inactive metabolite might increase the free concentration of the active metabolite leading to enhanced inhibition of platelet aggregation. The plasma protein binding mechanism would offer an additional therapeutic strategy to optimize clopidogrel pharmacotherapy.

Are children undergoing cardiac surgery receiving antibiotics at subtherapeutic levels?

OBJECTIVES

Perioperative antibiotics have decreased-but not eradicated-postoperative infections. In patients undergoing cardiac surgery with cardiopulmonary bypass, the dilutional effect of the priming and any additional volume given during the procedure may lead to subtherapeutic antibiotic levels. Our aim was to determine if children undergoing cardiac surgery with cardiopulmonary bypass receive perioperative antibiotics at subtherapeutic levels.

METHODS

Using published pharmacokinetic data on cefuroxime, we developed a computer simulation model to generate a nomogram predicting patients at risk for subtherapeutic cefuroxime levels based on time from initial dosing and additional volume given.

RESULTS

A computer-generated 1-compartment pharmacokinetic model was created to predict cefuroxime plasma levels over time for patients of all weights and additional volumes given for both a 25- and 50-mg/kg intravenous dose. For example, following a 25-mg/kg dose, a patient receiving an additional volume of 275 mL/kg is predicted to be subtherapeutic (<16 mg/L=4×minimum inhibitory concentration) at 4 hours. Our nomogram predicts all patients will be subtherapeutic at 8 hours, consistent with general pediatrics dosing schemes. Following a 50-mg/kg dose, levels are predicted to be subtherapeutic after an additional volume of 315 mL/kg at 5.5 hours.

CONCLUSIONS

Our model predicts which patients undergoing cardiac surgery with cardiopulmonary will have subtherapeutic cefuroxime levels. This nomogram enables providers to determine when to administer additional antibiotics in patients receiving large additional volumes during cardiac surgeries. This rational approach to perioperative antibiotic dosing may result in a reduction in postoperative infection in this vulnerable patient population.

An ethinyl estradiol-levonorgestrel containing oral contraceptive does not alter cytochrome P4502C9 in vivo activity

Oral contraceptives have been in wide use for more than 50 years. Levonorgestrel, a commonly employed progestin component of combined oral contraceptives, was implicated in drug-drug interactions mediated via CYP2C9. Although in vitro studies refuted this interaction, there are no confirmatory in vivo studies. In the current study, we examined the phenotypic status of CYP2C9 using low-dose (125 mg) tolbutamide before and after oral contraceptive use in reproductive age women. Blood was collected 24 hours after the tolbutamide oral dose was administered, plasma was isolated, and tolbutamide concentration (C24) was measured using liquid chromatography-mass spectrometry. The natural logarithm of tolbutamide C24, a metric for CYP2C9 phenotype, was found to be equivalent (within 80%-125% equivalency boundaries) before and after oral contraceptive use. In conclusion, levonorgestrel-containing oral contraceptives, the most commonly used form of oral contraception, do not affect the status of the CYP2C9 enzyme. This suggests that it is safe to co-administer levonorgestrel-containing oral contraceptives and CYP2C9 substrates, which include a wide array of drugs.

Sulforaphane treatment in men with recurrent prostate cancer

5017

Background: Diets high in cruciferous vegetables are strongly associated with lower prostate cancer risk. Sulforaphane is a constituent of these foods postulated to harbor the anti-neoplastic activity based on pre-clinical evidence in multiple tumor models. Our own work demonstrates that sulforaphane inhibits HDAC function and suppresses AR signaling in prostate cancer cells (Gibbs, et al PNAS 2009). However, the anti-tumor efficacy and safety of sulforaphane in men with prostate cancer was unknown. Methods: In this single arm study, we treated patients with biochemical (PSA)-recurrence of prostate cancer with 200 µmol of sulforaphane extracts for up to 20 weeks. The primary endpoint was PSA response rate (>50% decline in PSA). Other efficacy endpoints included: maximal PSA decline and percent change in PSA from baseline to end of study. We also analyzed PSA doubling time changes using a mixed effects model. Genotyping for GSTM1 that contributes to sulforaphane metabolism, sulforaphane pharmacokinetics (PK), and pharmacodynamic (PD) measurements of HDAC inhibition in mononuclear cells (MCs) were also performed. Results: Twenty patients were enrolled, and 16/20 (80%) completed the pre-planned 20 weeks of treatment. One patient experienced a PSA decline >50%. Thirty-five percent of patients had lesser PSA declines (3% to 20%), and 15% of patients had a final PSA lower than baseline. There was a significant reduction in PSA doubling time (6 months pre-study vs. 9.4 months on-study, p=.013). Of note, testosterone levels remained non-castrate in all subjects. PK analysis demonstrated that GSTM1 null genotype correlated with longer sulforaphane T1/2 (half-life) (2.6 hours for GSTM1 null vs. 2.1 hours for GSTM1 intact, p=0.04). Sulforaphane treatment also increased histone acetylation in PD assays in MCs. Finally, no grade three adverse events were seen, and only one patient discontinued study treatment for toxicity (grade one GI discomfort). Conclusions: Treatment with 200 µmol per day of sulforaphane is feasible, safe, and inhibits HDAC function. This combined with the preliminary observation of PSA modulation, which may indicate biologic activity, provides the basis for dose escalation studies of sulforaphane in men with prostate cancer. Clinical trial information: NCT01228084.

Analysis of tacrolimus and creatinine from a single dried blood spot using liquid chromatography tandem mass spectrometry

Long term therapeutic drug monitoring and assessment of renal function are required in renal transplant recipients on immunosuppressant therapy such as tacrolimus. Dry blood spots (DBS) have been used successfully in the clinic for many years and offers a convenient, simple and non-invasive method for repeated blood tests. We developed and performed a preliminary validation of a method for the analysis of tacrolimus and creatinine from a single DBS using liquid chromatography-tandem mass spectrometric (LC-MS/MS). Tacrolimus and creatinine were extracted from a 6mm punch with a mixture of methanol/acetonitrile containing ascomycin and deuterated creatinine as internal standards. A 10 μl aliquot of the extract was analyzed directly after dilution for creatinine with normal phase high performance liquid chromatography and multiple reaction monitoring. The remainder of the extract was processed and analyzed for tacrolimus. The lower limit of quantification for tacrolimus was 1 ng/ml with accuracy of 0.34% bias and precision (CV) of 11.1%. The precision ranged from 1.33% to 7.68% and accuracy from -4.44% to 11.6% bias for the intra- and inter-day analysis. The lower limit of quantification of creatinine was 0.01 mg/dL with precision of 7.94%. Accuracy was based on recovery of additional creatinine spiked into whole blood samples and ranged from -2.45% bias at 5 mg/dL to 3.75% bias at 0.5 mg/dL. Intra- and inter-day precision was from 3.48 to 4.11%. The assay was further validated with DBS prepared from pediatric renal transplant recipients. There was excellent correlation between the levels of tacrolimus and creatinine obtained from the clinical laboratory and the DBS method developed. After additional validation, this assay may have a significant impact on compliance with medication intake as well as potentially lowering the cost associated with intravenous blood draws in clinical laboratories.

Maternal low-protein diet alters the expression of real-time quantitative polymerase chain reaction reference genes in an age-, sex-, and organ-dependent manner in rat offspring

Altered perinatal environment, often manifested as low birth weight, is thought to contribute to greater susceptibility for hypertension, hyperlipidemia, and diabetes as a result of epigenetic modifications and alteration of transcriptional activity for key genes. Real-time polymerase chain reaction is a useful technique for the quantitative determination of differences in transcriptional activity. Real-time quantitative polymerase chain reaction data analyses require normalization of transcriptional activity of target genes to an endogenous control, usually a reference gene. In response to reports of altered expression of reference genes in various experimental models, we hypothesized that adverse perinatal environment alters reference gene expression. We examined the expression of the following reference genes in the offspring of a rodent maternal low-protein diet model: β-actin, hypoxanthine phosphoribosyltransferase 1, TATA-box-binding protein, glyceraldehyde-3-phosphate dehydrogenase, and glucuronidase-β in brain, heart, kidneys, and intestines. We found altered expression in brain, heart, and kidneys for each of the reference genes measured; these effects were age, organ, and sex dependent. Glyceraldehyde-3-phosphate dehydrogenase and glucuronidase-β were found to be the least affected by these variables, whereas hypoxanthine phosphoribosyltransferase 1 was the most inconsistent. Our findings underscore the importance of empirical determination of a reliable reference gene for real-time polymerase chain reaction studies in the low-protein diet model.

Prolonged monitoring of ethinyl estradiol and levonorgestrel levels confirms an altered pharmacokinetic profile in obese oral contraceptives users

BACKGROUND

Pharmacokinetic (PK) parameters based on short sampling times (48 h or less) may contain inaccuracies due to their dependency on extrapolated values. This study was designed to measure PK parameters with greater accuracy in obese users of a low-dose oral contraceptive (OC) and to correlate drug levels with assessments of end-organ activity.

STUDY DESIGN

Obese [body mass index (BMI) ≥30 kg/m2], ovulatory, otherwise healthy women (n=32) received an OC containing 20 mcg ethinyl estradiol (EE)/100 mcg levonorgestrel (LNG) for two cycles. EE and LNG PK parameters were characterized for 168 h at the end of Cycle 1. During cycle 2, biweekly outpatient visits were performed to assess cervical mucus, monitor ovarian activity with transvaginal ultrasound and obtain serum samples to measure EE, LNG, estradiol and progesterone levels. PK parameters were calculated and correlated with end-organ activity and compared against control samples obtained from normal and obese women sampled up to 48 h in a previous study. Standard determination of PK accuracy was performed, defined by the dependency on extrapolated values ('excess' area under the curve of 25% or less).

RESULTS

The mean BMI was 39.4 kg/m2 (SD 6.6) with a range of 30-64 kg/m2. Key LNG PK parameters were as follows: clearance, 0.52 L/h (SD 0.24); half-life, 65 h (SD 40); area under the curve (AUC), 232 h*ng/mL (SD 102); and time to reach steady state, 13.6 days (SD 8.4). The majority of subjects had increased ovarian activity with diameter of follicles ≥8 mm (n=25), but only seven women had follicles ≥10 mm plus cervical mucus scores ≥5. Evidence of poor end-organ suppression did not correlate with the severity of the alterations in PK. As compared to historical normal and obese controls (48-h PK sampling), clearance, half-life, AUC and time to reach steady state were found to be significantly different (p≤.05) in obese women undergoing a longer duration of PK sampling (168 h). Longer sampling also improved PK accuracy for obese women (excess AUC 20%) as compared to both normal and obese controls undergoing shorter sampling times (48 h) with excess AUCs of 25% and 50%, respectively.

CONCLUSIONS

Obesity results in significant alterations in OC steroid PK parameters, but the severity of these alterations did not correlate with end-organ suppression. A longer PK sampling interval (168 h vs. 48 h) improved the accuracy of PK testing.

Maternal obesity alters feto-placental cytochrome P4501A1 activity

Cytochrome P4501A1 (CYP1A1), an important drug metabolizing enzyme, is expressed in human placenta throughout gestation as well as in fetal liver. Obesity, a chronic inflammatory condition, is known to alter CYP enzyme expression in non-placental tissues. In the present study, we test the hypothesis that maternal obesity alters the distribution of CYP1A1 activity in feto-placental unit. Placentas were collected from non-obese (BMI < 30) and obese (BMI > 30) women at term. Livers were collected from gestation day 130 fetuses of non-human primates fed either control diet or high-fat diet (HFD). Cytosol and microsomes were collected using differential centrifugation, and incubated with 7-ethoxyresorufin. The CYP1A1 specific activity (pmoles of resorufin formed/min/mg of protein) was measured at excitation/emission wavelength of 530/590 nm. Placentas of obese women had significantly reduced microsomal CYP1A1 activity compared to non-obese women (0.046 vs. 0.082; p < 0.05); however no such effect was observed on cytosolic activity. Similarly, fetal liver from HFD fed mothers had significantly reduced microsomal CYP1A1 activity (0.44 ± 0.04 vs. 0.20 ± 0.10; p < 0.05), with no significant difference in cytosolic CYP1A1 activity (control, 1.23 ± 0.20; HFD, 0.80 ± 0.40). Interestingly, multiple linear regression analyses of placental efficiency indicate cytosolic CYP1A1 activity is a main effect (5.67 ± 2.32 (β ± SEM); p = 0.022) along with BMI (-0.57 ± 0.26; p = 0.037), fetal gender (1.07 ± 0.26; p < 0.001), and maternal age (0.07 ± 0.03; p = 0.011). In summary, while maternal obesity affects microsomal CYP1A1 activity alone, cytosolic activity along with maternal BMI is an important determinant of placental efficiency. Together, these data suggest that maternal lifestyle could have a significant impact on CYP1A1 activity, and hints at a possible role for CYP1A1 in feto-placental growth and thereby well-being of fetus.

Effect of the ethinylestradiol/levonorgestrel combined oral contraceptive on the activity of cytochrome P4503A in obese women

AIM(S)

While it is known that CYP3A4/5 activity is decreased with combined oral contraceptive (COC) use and obesity suppresses CYP expression, the combined effects of obesity and COC use on CYP3A4/5 activity are unclear. Therefore, our aim was to examine the effect of COC usage on CYP3A4/5 activity in obese women.

METHODS

Thirty-four, obese (body mass index, BMI > 30 kg m(-2)) women of reproductive age (18-35 years old) were placed on a COC pill containing 20 µg ethinylestradiol/100 µg levonorgestrel for 21 days starting at the onset of menses. A midazolam pharmacokinetic study was conducted prior to initiation and after 21 days of COC treatment. Serial blood samples were collected and plasma concentrations of midazolam were measured using liquid chromatography tandem mass spectrometry. Pharmacokinetic parameters were estimated using a non-compartmental method.

RESULTS

Midazolam clearance, a surrogate measure of CYP3A4/5 activity, was significantly decreased upon COC use (63.3 l h(-1) vs. 53.9 l h(-1), P < 0.05). A median decrease of 5.6 l h(-1) (95% CI -4.1, 13.3 l h(-1)) was observed. However, the magnitude of change was similar to that reported in women with normal BMI.

CONCLUSIONS

Although we hypothesized that obesity might amplify the impact on CYP3A4/5 activity in COC users, we found that this was not the case. This finding is reassuring regarding potential additional drug-drug interactions in obese COC users as CYP3A4/5 is a major enzyme in the metabolism of many marketed drugs.

Tacrolimus pharmacokinetics in Hispanic children after kidney transplantation

Ethnic differences in drug pharmacokinetics are well recognized including that for tacrolimus (TAC) in adult subjects. However, similar knowledge among pediatric populations is missing. Our limited retrospective study compares steady-state pharmacokinetics of TAC in Hispanic versus non-Hispanic children. Serial blood samples were collected and whole blood concentrations of TAC were measured using radioimmunoassay. Compared with non-Hispanic children, Hispanic children had lower measures of drug exposure (maximum drug concentration [Cmax] and area under the drug concentration-time curve [AUC0-∞]), higher volume of distribution, and faster clearance. Interestingly, only in Hispanic children, significant correlations were found between body weight and clearance, age and volume of distribution, and Schwartz estimated glomerular filtration rate and half-life. In conclusion, our study suggests that ethnic differences exist between Hispanic and non-Hispanic children in TAC PK, and based on our preliminary findings, either a higher or more frequent TAC dosing may be required for effective immunosuppression therapy in Hispanic children.

Maternal protein restriction during pregnancy and lactation in rats imprints long-term reduction in hepatic lipid content selectively in the male offspring

Maternal protein restriction during pregnancy and lactation reduces whole body lipid stores and alters lipid homeostasis in the adult offspring. Lipid homeostasis in the body is regulated, in part, by the liver via the metabolic processes of synthesis and utilization of lipids. The present study tested the hypothesis that maternal protein restriction will imprint changes in hepatic lipid metabolism and thereby alter the hepatic lipid content of the adult offspring. Pregnant rats were fed purified diets containing 19% protein (control group) or 8% protein (low-protein group) throughout pregnancy and lactation. On day 28, pups from both groups were weaned onto regular laboratory chow. On days 65 and 150, male and female pups from each litter in both groups were killed and blood and liver collected. Maternal protein restriction was found to reduce birth weight and produce long-term reduction in the body weight of the offspring. On day 65, liver triglyceride content was decreased by 40% in the male offspring that were fed a low-protein diet. The reduction in liver triglyceride content persisted until day 150, at which time it was accompanied by decreases in hepatic cholesterol content. No such changes were observed in the female offspring. To determine if the alterations in liver lipid content resulted in compensatory changes in liver carbohydrate stores, hepatic glycogen content was measured in male offspring. Hepatic glycogen content was similar between the 2 groups on days 65 and 150. In conclusion, the present study in rats showed that maternal protein restriction during pregnancy and lactation imprints long-term changes in hepatic lipid content selectively in the male offspring.

Pharmacokinetic study of lipoic acid in multiple sclerosis: comparing mice and human pharmacokinetic parameters

Lipoic acid is a natural antioxidant available as an oral supplement from a number of different manufacturers. Lipoic acid administered subcutaneously is an effective therapy for murine experimental autoimmune encephalomyelitis, a model of multiple sclerosis. The aim of this study was to compare serum lipoic acid levels with oral dosing in patients with multiple sclerosis with serum levels in mice receiving subcutaneous doses of lipoic acid. We performed serum pharmacokinetic studies in patients with multiple sclerosis after a single oral dose of 1200 mg lipoic acid. Patients received one of the three different racemic formulations randomly: tablet (Formulation A) and capsules (Formulations B and C). Mice pharmacokinetic studies were performed with three different subcutaneous doses (20, 50 and 100 mg/kg racemic lipoic acid). The pharmacokinetic parameters included Maximum Serum Concentrations (C(max) in microg/ml) and area under the curve (0-infinity) (AUC ( 0-infinity) in microg*min/ml). We found mean C(max) and AUC (0-infinity) in patients with multiple sclerosis as follows: group A (N = 7) 3.8 +/- 2.6 and 443.1 +/- 283.9; group B (N = 8) 9.9 +/- 4.5 and 745.2 +/- 308.7 and group C (N = 8) 10.3 +/- 3.8 and 848.8 +/- 360.5, respectively. Mean C(max) and AUC (0-infinity) in the mice were: 100 mg/kg lipoic acid: 30.9 +/- 2.9 and 998 +/- 245; 50 mg/kg lipoic acid: 7.6 +/- 1.4 and 223 +/- 20; 20 mg/kg lipoic acid: 2.7 +/- 0.7 and 119 +/- 33. We conclude that patients taking 1200 mg of lipoic acid from two of the three oral formulations achieved serum C(max) and AUC levels comparable to that observed in mice receiving 50 mg/kg subcutaneous dose of lipoic acid, which is a highly therapeutic dose in experimental autoimmune encephalomyelitis. A dose of 1200 mg oral lipoic acid can achieve therapeutic serum levels in patients with multiple sclerosis.

Association of platelet responsiveness with clopidogrel metabolism: role of compliance in the assessment of "resistance"

BACKGROUND

Noncompliance is probably the major cause of clopidogrel "resistance." However, noncompliance is difficult to prove without confirming that the drug has been administered. Therefore, detection of plasma clopidogrel and/or metabolite(s) as the reliable objective method to confirm compliance is important.

METHODS

We sought to correlate the inhibition of platelet aggregation (IPA) with plasma levels of unchanged clopidogrel (UC), active thiol metabolite (ATM), and inactive carboxyl metabolite (ICM) in a large cohort of patients with coronary artery disease and ischemic stroke treated with clopidogrel. We conducted secondary post-hoc analyses of IPA and plasma UC, ATM, and ICM in a dataset consisting of presumably compliant patients with coronary disease (n = 422) and post-stroke (n = 209).

RESULTS

Overall noncompliance rate was 22% (n = 138), while such risks were significantly higher in stroke survivors (n = 79, or 38%) when compared to patients with coronary disease (14%; n = 59; P = .001). Only ICM (19,154 +/- 7,228 ng/ml) was suitable for detecting compliance, while UC (15.2 +/- 9.4 ng/ml), and ATM (8.1 +/- 3.7 ng/ml) in most cases are barely detectable, and diminish over time in the stored samples. The best correlation with IPA (r2 = 0.847) was observed for active metabolite, followed by unchanged clopidogrel (r2 = 0.602), and finally inactive metabolite (r2 = 0.529). The predictive value for noncompliance was also high for inactive metabolite (c-statistic = 0.911).

CONCLUSIONS

Therapy with clopidogrel is associated with double-digit underestimated risks for noncompliance, especially in stroke survivors, supporting the hypothesis that lack of IPA, and clopidogrel "resistance" are attributed to hidden noncompliance. Plasma ICM, but not UC, or ATM is a useful marker to monitor compliance to clopidogrel in registries and clinical trials.

Application of platelet function testing to the bedside

The ability to test platelet reactivity in clinical practice could help in making informed decisions on both initiation and titration of anti-platelet drug therapies. However, many barriers still remain to the effective implementation of such techniques. Many tests used in the research literature are not yet available for practical, clinical use. Platelet aggregometry, while informative and currently available for bedside use, needs additional research before routine clinical use can be recommended. This review will highlight and update contemporary issues of bedside platelet testing for the clinician and comment on future areas of clinical research.

Impact of obesity on oral contraceptive pharmacokinetics and hypothalamic-pituitary-ovarian activity

BACKGROUND

This study was conducted to determine whether increased body mass index (BMI) affects oral contraceptive (OC) pharmacokinetics and suppression of hypothalamic-pituitary-ovarian (HPO) axis activity.

STUDY DESIGN

Ovulatory reproductive-age women with normal weight (BMI <25 kg/m(2); n=10) and with obesity (BMI >30 kg/m(2); n=10) received OCs for two cycles (prospective cohort). Subjects were admitted for two 48-h inpatient stays at the beginning and end of the hormone-free interval. Ethinyl estradiol and levonorgestrel (LNG) levels were evaluated during both inpatient stays. Gonadotropin pulsatility (follicle-stimulating hormone and luteinizing hormone) was measured during the second inpatient stay. Estradiol (E(2)) and progesterone (P) were measured daily during inpatient stays and twice per week in Cycle 2.

RESULTS

BMI was greater in the obese compared to the normal-BMI group [37.3 kg/m(2) (SD, 6.0) vs. 21.9 kg/m(2) (SD, 1.6); p<.05]. The LNG half-life was significantly longer in the obese group (52.1+/-29.4 vs. 25.6+/-9.3 h, p<.05), which correlated with a lower maximum LNG concentration on Cycle 2, Day 1 [1.9 ng/mL (SD, 0.5) vs. 2.5 ng/mL (SD, 0.7)] and a longer time to reach steady state (10 vs. 5 days) in obese women. There were no significant differences in volume of distribution between groups. LH pulse parameters did not differ statistically between groups but trended toward greater HPO activity in the obese group. Additionally, more obese (6/10 vs. 3/10 normal BMI, p>.05) women exhibited E(2) levels consistent with development of a dominant follicle and P levels consistent with ovulation (2/10 vs. 1/10) during Cycle 2.

CONCLUSIONS

Compared to women with normal BMI, obese women exhibit differences in OC pharmacokinetics that are associated with greater HPO activity.

Effect of Perinatal Low Protein Diets on the Ontogeny of Select Hepatic Cytochrome P450 Enzymes and Cytochrome P450 Reductase in the Rat

In the present study, we administered two low protein diets (LPDs) to rats during pregnancy and lactation and determined their effect on the ontogeny of select hepatic cytochrome P450 (P450) isoforms in their offspring. The L93 and LM76 LPDs were derived from the American Society of Nutrition recommended AIN93G and a modified version of the AIN76A purified control diets, respectively. The LPDs contained 8% crude protein in the form of casein, whereas the purified control diets contained 19% casein. A regular cereal-based diet (NP) was also included, and, therefore, a total of five groups were tested. Pups in all five groups were weaned onto a regular NP diet on postnatal day 28. Perinatal LPD altered the activities of a number of P450 isoforms in 28-day-old male and female offspring. However, nutritional rehabilitation abolished most of these changes as evidenced by lack of differences between the five groups in the activities of P450 isoforms in either 65- or 150-day-old offspring. Interestingly, 58-day-old female offspring in the LM76 group but not those in the L93 group exhibited shorter hexobarbital sleep time than the purified control group. However, hexobarbital hydroxylase activity and the amount of CYP2C12 protein, an important P450 isoform involved in hexobarbital metabolism in females, were unchanged. This suggests that the decrease in hexobarbital sleep time in this group is not due to an increase in the activity of hexobarbital-metabolizing enzymes. In summary, perinatal LPDs produced transient alterations in activities of select hepatic P450s and resulted in a gender- and diet-dependent long-term alteration in hexobarbital pharmacodynamics.

Two low protein diets differentially affect food consumption and reproductive performance in pregnant and lactating rats and long-term growth in their offspring

We fed 2 low protein diets (LPD) to rats during pregnancy and lactation, and compared food intake and reproductive performance in the dams, and long-term growth in their offspring. The L93 and LM76 LPDs were derived from the American Society of Nutrition's recommended AIN93G and a modified version of the AIN76A purified control diets, respectively. The LPDs contained 8% crude protein in the form of casein and differed in their fat and carbohydrate sources. The purified control diets contained 19% crude protein. A regular cereal-based diet was also included, therefore, a total of 5 groups were tested. Blood urea nitrogen concentrations in dams of both LPD groups were lower than their respective controls, confirming decreased protein intake. The LM76 diet lowered food consumption of dams and produced energy malnourishment during pregnancy that persisted throughout lactation. In contrast, the L93 diet produced energy malnourishment only during lactation. Offspring of both LPD groups exhibited lower birth weights than their respective controls. Despite initiating nutritional rehabilitation at weaning (d 28), perinatal administration of both low protein diets produced long-term reductions in the body weight of male offspring. Interestingly, in the female offspring, the LM76 diet reduced birth weight for the entire duration of the study (180 d), whereas the L93 diet produced a relatively short-term (up to 58 d) reduction in body weight. This suggests that the imprinting effect of the perinatal nutritional environment on body weight is diet and gender dependent. The performance of the purified control diet groups were similar to the nonpurified diet group in most measured biochemical indices, with the notable exception of a decrease in the body-weight normalized kidney weight of the dams.

Cytosolic sulfotransferases

Sulfoconjugation (Sulfation or Sulfonation) is an important reaction in the phase II biotransformation of a wide number of endogenous and foreign chemicals, including: drugs, toxic chemicals, hormones, and neurotransmitters. The reaction is catalyzed by the members of the cytosolic sulfotransferase (SULT) superfamily, consisting of ten functional genes in humans. Sulfation reaction in living cells is reversed by sulfatase, which hydrolyses the sulfonated conjugates. It has a major role in regulating the endocrine status of an individual by modulating the activity of steroid hormones, their biosynthesis, and the metabolism of catecholamines. Sulfonation is a key reaction in the body's 'chemical' defense against xenobiotics. Although the primary function of sulfoconjugation is to permit detoxification of the compound, it also results in the activation of chemical procarcinogens, such as certain dietary and environmental agents into carcinogens. In this review, we summarize our current understanding of the structure of mammalian cytosolic sulfotransferases and their role in human steroid associated cancers and in the bioactivation of chemical carcinogens.