scholarly journals Regulatory Effects of Cannabidiol on Mitochondrial Functions: A Review

Cells ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 1251
Author(s):  
John Zewen Chan ◽  
Robin Elaine Duncan
Keyword(s):  
Mitochondrial Fission ◽  
Plasma Concentrations ◽  
Current Data ◽  
Pharmacokinetic Studies ◽  
Specific Response ◽  
Neural Cells ◽  
Human Pharmacokinetics ◽  
Intrinsic Apoptosis ◽  
Ferritin Concentration ◽  
Mitochondrial Functions

Cannabidiol (CBD) is part of a group of phytocannabinoids derived from Cannabissativa. Initial work on CBD presumed the compound was inactive, but it was later found to exhibit antipsychotic, anti-depressive, anxiolytic, and antiepileptic effects. In recent decades, evidence has indicated a role for CBD in the modulation of mitochondrial processes, including respiration and bioenergetics, mitochondrial DNA epigenetics, intrinsic apoptosis, the regulation of mitochondrial and intracellular calcium concentrations, mitochondrial fission, fusion and biogenesis, and mitochondrial ferritin concentration and mitochondrial monoamine oxidase activity regulation. Despite these advances, current data demonstrate contradictory findings with regard to not only the magnitude of effects mediated by CBD, but also to the direction of effects. For example, there are data indicating that CBD treatment can increase, decrease, or have no significant effect on intrinsic apoptosis. Differences between studies in cell type, cell-specific response to CBD, and, in some cases, dose of CBD may help to explain differences in outcomes. Most studies on CBD and mitochondria have utilized treatment concentrations that exceed the highest recorded plasma concentrations in humans, suggesting that future studies should focus on CBD treatments within a range observed in pharmacokinetic studies. This review focuses on understanding the mechanisms of CBD-mediated regulation of mitochondrial functions, with an emphasis on findings in neural cells and tissues and therapeutic relevance based on human pharmacokinetics.

Pharmacokinetics of culture-directed antibiotics for the treatment of peritonitis in automated peritoneal dialysis: A systematic narrative review

2021 ◽  
Vol 41 (3) ◽  
pp. 261-272
Author(s):  
Chau Wei Ling ◽  
Kamal Sud ◽  
Connie Van ◽  
Syed Tabish Razi Zaidi ◽  
Rahul P. Patel ◽  
...  
Keyword(s):  
Peritoneal Dialysis ◽  
Case Reports ◽  
Plasma Concentrations ◽  
Case Series ◽  
Therapeutic Drug ◽  
Pharmacokinetic Studies ◽  
Pharmacokinetic Data ◽  
Automated Peritoneal Dialysis ◽  
Final Study ◽  
Drug Plasma

The objectives of this study were to provide a summary of the pharmacokinetic data of some intraperitoneal (IP) antibiotics that could be used for both empirical and culture-directed therapy, as per the ISPD recommendations, and examine factors to consider when using IP antibiotics for the management of automated peritoneal dialysis (APD)-associated peritonitis. A literature search of PubMed, EMBASE, Scopus, MEDLINE and Google Scholar for articles published between 1998 and 2020 was conducted. To be eligible, articles had to describe the use of antibiotics via the IP route in adult patients ≥18 years old on APD in the context of pharmacokinetic studies or case reports/series. Articles describing the use of IP antibiotics that had been recently reviewed (cefazolin, vancomycin, gentamicin and ceftazidime) or administered for non-APD-associated peritonitis were excluded. A total of 1119 articles were identified, of which 983 abstracts were screened. Seventy-three full-text articles were assessed for eligibility. Eight records were included in the final study. Three reports had pharmacokinetic data in patients on APD without peritonitis. Each of cefepime 15 mg/kg IP, meropenem 0.5 g IP and fosfomycin 4 g IP given in single doses achieved drug plasma concentrations above the minimum inhibitory concentration for treating the susceptible organisms. The remaining five records were case series or reports in patients on APD with peritonitis. While pharmacokinetic data support intermittent cefepime 15 mg/kg IP daily, only meropenem 0.5 g IP and fosfomycin 4 g IP are likely to be effective if given in APD exchanges with dwell times of 15 h. Higher doses may be required in APD with shorter dwell times. Information on therapeutic efficacy was derived from case reports/series in individual patients and without therapeutic drug monitoring. Until more pharmacokinetic data are available on these antibiotics, it would be prudent to shift patients who develop peritonitis on APD to continuous ambulatory peritoneal dialysis, where pharmacokinetic information is more readily available.

scholarly journals Toxicity and Pharmacokinetic Studies of Lidocaine and Its Active Metabolite, Monoethylglycinexylidide, in Goat Kids

Animals ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 142
Author(s):  
Dinakaran Venkatachalam ◽  
Paul Chambers ◽  
Kavitha Kongara ◽  
Preet Singh
Keyword(s):  
Total Dose ◽  
Plasma Concentrations ◽  
Subcutaneous Administration ◽  
Lidocaine Hydrochloride ◽  
Pharmacokinetic Parameters ◽  
Pharmacokinetic Studies ◽  
Liquid Chromatography Mass Spectrometry ◽  
Elimination Half ◽  
The Mean ◽  
Safe Dose

This study determined the convulsant plasma concentrations and pharmacokinetic parameters following cornual nerve block and compared the results to recommend a safe dose of lidocaine hydrochloride for goat kids. The plasma concentrations of lidocaine and monoethylglycinexylidide (MGX) were quantified using liquid chromatography-mass spectrometry. A total dose of 7 mg/kg body weight (BW) was tolerated and should therefore be safe for local and regional anesthesia in goat kids. The mean plasma concentration and mean total dose that produced convulsions in goat kids were 13.59 ± 2.34 µg/mL and 12.31 ± 1.42 mg/kg BW (mean ± S.D.), respectively. The absorption of lidocaine following subcutaneous administration was rapid with Cmax and Tmax of 2.12 ± 0.81 µg/mL and 0.33 ± 0.11 h, respectively. The elimination half-lives (t½λz) of lidocaine hydrochloride and MGX were 1.71 ± 0.51 h and 3.19 ± 1.21 h, respectively. Injection of 1% lidocaine hydrochloride (0.5 mL/site) was safe and effective in blocking the nerves supplying horn buds in goat kids.

scholarly journals Improving glucocorticoid replacement therapy using a novel modified-release hydrocortisone tablet: a pharmacokinetic study

2009 ◽  
Vol 161 (1) ◽  
pp. 119-130 ◽  
Author(s):  
Gudmundur Johannsson ◽  
Ragnhildur Bergthorsdottir ◽  
Anna G Nilsson ◽  
Hans Lennernas ◽  
Thomas Hedner ◽  
...  
Keyword(s):  
Single Dose ◽  
Replacement Therapy ◽  
Plasma Cortisol ◽  
Plasma Concentrations ◽  
Pharmacokinetic Studies ◽  
Double Blind ◽  
Once Daily ◽  
Physiological Serum ◽  
Cortisol Levels ◽  
Dual Release

BackgroundEndogenous plasma cortisol levels have a well-defined circadian rhythm. The aim of this project is to develop a once daily oral dual-release formulation for cortisol replacement therapy that mimics the diurnal variation in the plasma cortisol profile.ObjectiveTo determine single-dose plasma pharmacokinetics and dose-proportionality of oral 5 and 20 mg dual-release hydrocortisone tablets in healthy volunteers. In addition, the effect of food intake was investigated for the 20 mg dose.DesignA randomised, controlled, two-way cross-over, double-blind, phase I study of oral hydrocortisone (modified (dual) release; 5 and 20 mg) with an open food-interaction arm.MethodsThe single dose pharmacokinetic studies were performed with betamethasone suppression. The two first study days were blinded and randomised between morning administration of 5 and 20 mg tablet in a fasting state. The third day was open with a 20 mg tablet taken 30 min after a high-calorie, high-fat meal. The plasma samples were assayed using both a validated LC–MS/MS and an immunoassay. The plasma pharmacokinetic variables were calculated using non-compartmental data analysis.ResultsThe time to reach a clinically significant plasma concentration of cortisol (>200 nmol/l) was within 20 min and a mean peak of 431 (s.d. 126) nmol/l was obtained within 50 min after administration of the 20 mg tablet. Plasma cortisol levels remained above 200 nmol/l for around 6 h thereafter and all plasma concentrations 18–24 h after intake were below 50 nmol/l. In the fed state the time to reach 200 nmol/l was delayed by 28 and 9 min based on LC–MS/MS and immunoassay, respectively. The 5 and 20 mg tablets produced an increase in plasma exposure of cortisol that was not fully dose proportional.ConclusionThe dual release hydrocortisone tablet with once-daily administration produced a diurnal plasma cortisol profile mimicking the physiological serum cortisol profile.

scholarly journals Clinical Validation of a Volumetric Absorptive Micro-Sampling Device for Pharmacokinetic Studies With Tranexamic Acid

2021 ◽  
Vol 12 ◽  
Author(s):  
Stanislas Grassin-Delyle ◽  
Elodie Lamy ◽  
Michaela Semeraro ◽  
Iléana Runge ◽  
Jean-Marc Treluyer ◽  
...  
Keyword(s):  
Tranexamic Acid ◽  
Whole Blood ◽  
Plasma Concentrations ◽  
High Sensitivity ◽  
Pharmacokinetic Studies ◽  
Limits Of Agreement ◽  
Sampling Device ◽  
Average Bias ◽  
Alternative Routes ◽  
Matched Samples

We assessed the accuracy of tranexamic acid (TXA) concentrations measured in capillary whole blood using volumetric absorptive micro-sampling (VAMS) devices. Paired venous and VAMS capillary blood samples were collected from 15 healthy volunteers participating in a pharmacokinetic study of alternative routes (oral, IM and IV) of administering TXA. To assess accuracy across a range of concentrations, blood was drawn at different times after TXA administration. We measured TXA concentrations in plasma, whole blood from samples collected by venepuncture and whole blood from venous and capillary samples collected using VAMS devices. TXA was measured using a validated high sensitivity liquid chromatography - mass spectrometry method. We used Bland-Altman plots to describe the agreement between the TXA concentrations obtained with the different methods. In the 42 matched samples, the mean plasma TXA concentration was 14.0 mg/L (range 2.6–36.5 mg/L) whereas the corresponding whole blood TXA concentration was 7.7 mg/L (range 1.6–17.5 mg/L). When comparing TXA concentrations in VAMS samples of venous and capillary whole blood, the average bias was 0.07 mg/L (lower and upper 95% limits of agreement: −2.1 and 2.2 mg/L respectively). When comparing TXA concentrations in venous whole blood and VAMS capillary whole blood, the average bias was 0.7 mg/L (limits of agreement: −2.7 and 4.0 mg/L). Volumetric absorptive micro-sampling devices are sufficiently accurate for use in pharmacokinetic studies of tranexamic acid treatment in the range of plasma concentrations relevant for the assessment of fibrinolysis inhibition.

scholarly journals Pharmacodynamics of Five Anthraquinones (Aloe-emodin, Emodin, Rhein, Chysophanol, and Physcion) and Reciprocal Pharmacokinetic Interaction in Rats with Cerebral Ischemia

Molecules ◽  
2019 ◽  
Vol 24 (10) ◽  
pp. 1898 ◽  
Author(s):  
Rong-Rong Li ◽  
Xue-Fang Liu ◽  
Su-Xiang Feng ◽  
Sheng-Nan Shu ◽  
Pei-Yang Wang ◽  
...  
Keyword(s):  
Cerebral Ischemia ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Plasma Concentrations ◽  
Pharmacokinetic Parameters ◽  
Pharmacokinetic Studies ◽  
Plasma Exposure ◽  
Significant Difference ◽  
Aloe Emodin ◽  
Exposure Levels

(1) Background: Rhubarb anthraquinones—a class of components with neuroprotective function—can be used to alleviate cerebral ischemia reperfusion injury. (2) Methods: The three pharmacodynamic indicators are neurological function score, brain water content, and cerebral infarction area; UPLC-MS/MS was used in pharmacokinetic studies to detect plasma concentrations at different time points, and DAS software was used to calculate pharmacokinetic parameters in a noncompartmental model. (3) Results: The results showed that the pharmacodynamics and pharmacokinetics of one of the five anthraquinone aglycones could be modified by the other four anthraquinones, and the degree of interaction between different anthraquinones was different. The chrysophanol group showed the greatest reduction in pharmacodynamic indicators comparing with other four groups where the rats were administered one of the five anthraquinones, and there was no significant difference between the nimodipine group. While the Aloe-emodin + Physcion group showed the most obvious anti-ischemic effect among the groups where the subjects were administered two of the five anthraquinones simultaneously. Emodin, rhein, chrysophanol, and physcion all increase plasma exposure levels of aloe-emodin, while aloe-emodin lower their plasma exposure levels. (4) Conclusions: This experiment provides a certain preclinical basis for the study of anthraquinone aglycones against cerebral ischemia and a theoretical basis for the study of the mechanism of interaction between anthraquinones.

scholarly journals Impact of Obesity on the Rate of Recurrent Spontaneous Preterm Birth in Women Treated with 17-alpha Hydroxyprogesterone Caproate

2018 ◽  
Vol 35 (09) ◽  
pp. 809-814 ◽  
Author(s):  
Lara Lemon ◽  
Allison Serra ◽  
Shringi Sharma ◽  
Raman Venkataramanan ◽  
Steve Caritis ◽  
...  
Keyword(s):  
Preterm Birth ◽  
Controlled Trial ◽  
Plasma Concentrations ◽  
Pharmacokinetic Studies ◽  
Maternal Body Mass Index ◽  
Omega 3 ◽  
Spontaneous Preterm Birth ◽  
Obesity Class ◽  
Hydroxyprogesterone Caproate ◽  
The Impact

Objective We sought to determine if the rate of recurrent spontaneous preterm birth (PTB) in women treated with 17-α hydroxyprogesterone caproate (17-OHPC) is modified by maternal body mass index (BMI). Study Design We performed a secondary analysis of the Maternal-Fetal Medicine Units Network omega-3 fatty acid supplementation to prevent recurrent PTB randomized controlled trial. All women received 17-OHPC. Results A total of 708 women were included. Rates of spontaneous PTB did not vary significantly by BMI category. With stratification by obesity class and gestational age at delivery, the unadjusted risk for PTB using earlier gestational cutoffs (< 35, 32, and 28 weeks) demonstrated an association between preterm delivery and increasing severity of obesity. With adjustment for potential confounders, there was no statistically significant relationship between BMI and spontaneous PTB. Conclusion We demonstrated that the risk of PTB in women receiving 250 mg 17-OHPC is not dependent on maternal BMI after adjustment for confounding variables. Pharmacokinetic studies have demonstrated a wide variation in plasma concentration of 17-OHPC across the population with likely considerable overlap in plasma concentrations among the obese and nonobese population. Further studies are needed to evaluate the impact of BMI on efficacy of 17-OHPC prior to any dose adjustment in this population.

scholarly journals Simultaneous Determination and Pharmacokinetic Characterization of Glycyrrhizin, Isoliquiritigenin, Liquiritigenin, and Liquiritin in Rat Plasma Following Oral Administration of Glycyrrhizae Radix Extract

Molecules ◽  
2019 ◽  
Vol 24 (9) ◽  
pp. 1816 ◽  
Author(s):  
You Jin Han ◽  
Bitna Kang ◽  
Eun-Ju Yang ◽  
Min-Koo Choi ◽  
Im-Sook Song
Keyword(s):  
Oral Administration ◽  
Analytical Method ◽  
Plasma Concentrations ◽  
Rat Plasma ◽  
Pharmacokinetic Studies ◽  
Elution Time ◽  
Glycyrrhizae Radix ◽  
Single Oral Administration ◽  
Limit Of Quantitation ◽  
Liquid Chromatography Tandem Mass

Glycyrrhizae Radix is widely used as herbal medicine and is effective against inflammation, various cancers, and digestive disorders. We aimed to develop a sensitive and simultaneous analytical method for detecting glycyrrhizin, isoliquiritigenin, liquiritigenin, and liquiritin, the four marker components of Glycyrrhizae Radix extract (GRE), in rat plasma using liquid chromatography-tandem mass spectrometry and to apply this analytical method to pharmacokinetic studies. Retention times for glycyrrhizin, isoliquiritigenin, liquiritigenin, and liquiritin were 7.8 min, 4.1 min, 3.1 min, and 2.0 min, respectively, suggesting that the four analytes were well separated without any interfering peaks around the peak elution time. The lower limit of quantitation was 2 ng/mL for glycyrrhizin and 0.2 ng/mL for isoliquiritigenin, liquiritigenin, and liquiritin; the inter- and intra-day accuracy, precision, and stability were less than 15%. Plasma concentrations of glycyrrhizin, isoliquiritigenin, liquiritigenin, and liquiritin were quantified for 24 h after a single oral administration of 1 g/kg GRE to four rats. Among the four components, plasma concentration of glycyrrhizin was the highest and exhibited a long half-life (23.1 ± 15.5 h). Interestingly, plasma concentrations of isoliquiritigenin and liquiritigenin were restored to the initial concentration at 4–10 h after the GRE administration, as evidenced by liquiritin biotransformation into isoliquiritigenin and liquiritigenin, catalyzed by fecal lysate and gut wall enzymes. In conclusion, our analytical method developed for detecting glycyrrhizin, isoliquiritigenin, liquiritigenin, and liquiritin could be successfully applied to investigate their pharmacokinetic properties in rats and would be useful for conducting further studies on the efficacy, toxicity, and biopharmaceutics of GREs and their marker components.

Phase I and Pharmacologic Study of the Tyrosine Kinase Inhibitor SU101 in Patients With Advanced Solid Tumors

1999 ◽  
Vol 17 (4) ◽  
pp. 1095-1095 ◽  
Author(s):  
S. Gail Eckhardt ◽  
Jinee Rizzo ◽  
Kevin R. Sweeney ◽  
Gillian Cropp ◽  
Sharyn D. Baker ◽  
...  
Keyword(s):  
Tyrosine Kinase ◽  
Tyrosine Kinase Inhibitor ◽  
Dose Escalation ◽  
Kinase Inhibitor ◽  
Plasma Concentrations ◽  
Dose Schedule ◽  
Malignant Neoplasms ◽  
Pharmacokinetic Studies ◽  
Entire Treatment Period ◽  
Moderate Nausea

PURPOSE: To evaluate the clinical feasibility and pharmacologic behavior of the platelet-derived growth factor (PDGF) tyrosine kinase inhibitor SU101, administered on a prolonged, intermittent dosing schedule to patients with advanced solid malignancies. PATIENTS AND METHODS: Twenty-six patients were treated with SU101 doses ranging from 15 to 443 mg/m2 as a 24-hour continuous intravenous (IV) infusion weekly for 4 weeks, repeated every 6 weeks. Pharmacokinetic studies were performed to characterize the disposition of SU101 and its major active metabolite, SU0020. Immunohistochemical staining of PDGF-α and -β receptors was performed on malignant tumor specimens obtained at diagnosis. RESULTS: Twenty-six patients were treated with 52 courses (187 infusions) of SU101. The most common toxicities were mild to moderate nausea, vomiting, and fever. Two patients experienced one episode each of grade 3 neutropenia at the 333 and 443 mg/m2 dose levels. Dose escalation of SU101 above 443 mg/m2/wk was precluded by the total volume of infusate required, 2.5 to 3.0 L. Individual plasma SU101 and SU0020 concentrations were described by a one-compartment model that incorporates both first-order formation and elimination of SU0020. SU101 was rapidly converted to SU0020, which exhibited a long elimination half-life averaging 19 ± 12 days. At the 443 mg/m2/wk dose level, trough plasma SU0020 concentrations during weeks 2 and 4 ranged from 54 to 522 μmol/L. Immunohistochemical studies revealed PDGF-α and -β receptor staining in the majority (15 of 19) of malignant neoplasms. CONCLUSION: SU101 was well tolerated as a 24-hour continuous IV infusion at doses of up to 443 mg/m2/wk for 4 consecutive weeks every 6 weeks. Although further dose escalation was precluded by infusate volume constraints, this SU101 dose schedule resulted in the achievement and maintenance of substantial plasma concentrations of the major metabolite, SU0020, for the entire treatment period.

Pharmacokinetics of L-arginine during chronic administration to patients with hypercholesterolaemia

1999 ◽  
Vol 96 (2) ◽  
pp. 199-207 ◽  
Author(s):  
Oranee TANGPHAO ◽  
Stephan CHALON ◽  
Heitor MORENO ◽  
Brian B. HOFFMAN ◽  
Terrence F. BLASCHKE
Keyword(s):  
Nitric Oxide ◽  
Animal Studies ◽  
Peak Plasma ◽  
Plasma Concentrations ◽  
Area Under The Curve ◽  
Chronic Administration ◽  
Pharmacokinetic Studies ◽  
Acute Administration ◽  
Term Administration ◽  
Endothelial Nitric Oxide

Acute administration of L-arginine, the precursor of endothelial nitric oxide, has been shown to improve endothelial function in hypercholesterolaemic rabbits and humans. Animal studies suggest that this beneficial effect, which is thought to be related to the increased availability of nitric oxide, may not be sustained during chronic oral administration. Pharmacokinetic alterations may contribute to this observation. The present study was designed to examine the disposition of L-arginine in hypercholesterolaemic subjects during long-term administration. Plasma L-arginine concentrations were determined by HPLC in 10 patients (eight women and two men; mean age 46±16 years) after an intravenous dose of 10 or 30 g and an oral dose of 5 or 7 g. Pharmacokinetic studies were performed at regular intervals (4 weeks) during a 12-week period of oral L-arginine administration (14–21 g/day). The average plasma L-arginine concentrations before (baseline) and during administration were 16.1±1.2 and 22.5±1.3 μg/ml respectively (P< 0.05). Plasma concentrations of L-arginine remained above baseline throughout weeks 2–12. The L-arginine exposure, expressed as a normalized area-under-the-curve for 8 h (AUC0–8) after oral or intravenous doses during the first visit, was 894.4±118.7 and 1837.8±157.0 units respectively. There were no significant changes in peak plasma L-arginine concentrations or in the AUC0–8 after oral and intravenous doses during subsequent visits (P> 0.05). The mean non-renal clearance of L-arginine during the four visits remained constant. Knowledge of the pharmacokinetics of L-arginine may be useful in the design of clinical trials involving this agent, as well as in the interpretation of the pharmacodynamics of this important precursor of nitric oxide.

A Phase II, Open Label Study of AT-101 in Combination with Rituximab in Patients with Relapsed or Refractory Chronic Lymphocytic Leukemia.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 2838-2838 ◽  
Author(s):  
Januario E. Castro ◽  
Loria J. Olivier ◽  
Aguillon A. Robier ◽  
James Danelle ◽  
Suarez J. Carlos ◽  
...  
Keyword(s):  
High Risk ◽  
Chronic Lymphocytic Leukemia ◽  
Adverse Events ◽  
Plasma Concentrations ◽  
Leukemia Cell ◽  
Lymphocytic Leukemia ◽  
Leukemia Cells ◽  
Pharmacokinetic Studies ◽  
Cell Counts ◽  
Grade 3

Abstract Chronic lymphocytic leukemia (CLL) cells express high-levels of Bcl-2 and related anti-apoptotic proteins that collectively can enhance leukemia-cell survival and drug-resistance. AT-101 is an orally active BH3-mimetic that can inhibit the anti-apoptotic activity of Bcl-2-family-member proteins (e.g. Bcl-2, Bcl-XL, Mcl-1) and induce CLL cells to undergo apoptosis. Furthermore, we found that AT-101 also can enhance the cytotoxicity of rituximab for CLL cells in vitro. As such we conducted a phase 2 trial to evaluate the safety and activity of AT-101 when used together with rituximab to treat 12 patients who had relapsed/refractory CLL. Patients received AT-101, at 30 mg/d, for 21 or 28 days during each of three 28-day cycles. Rituximab was administered at 375 mg/m2 for 12 doses (total dose = 4,500 mg/m2) on days 1, 3, 5, 8, 15, 22, 29, 31, 33, 40, 57, 59, 61. The first dose of rituximab was given over two days to minimize infusion-related adverse events. The patients’ median age was 61.5 years (range 43–81). Nine patients were high risk and 3 were intermediate risk based on the modified Rai classification and had received a median of 2 prior regimens (range 1–8). Six patients had leukemia cells that expressed ZAP-70 and/or unmutated immunoglobulin variable region genes and 4 patients had either 11q deletions or complex cytogenetics. Six patients interrupted treatment due to adverse events, most of which were transient and without residual complications. Grade 1–2 gastrointestinal effects (e.g., nausea, vomiting) occurred in 11 patients, 2 of whom had grade 3/4 ileus. Six patients experienced treatment-associated fatigue (grade 1–2 in 5 and grade 3 in one). Other than ileus and fatigue the only grade 3/4 event noted was neutropenia. One patient without neutropenia died while undergoing treatment from community-acquired bacterial pneumonia[j1]. Pharmacokinetic studies demonstrated that the average Cmax of AT-101 was 565 ng/ml (280 – 805 ng/ml) at a Tmax of 3.1 hours (1.7 – 5.6 hrs.). Correlative science studies performed on leukemia cells isolated at various times after treatment demonstrated leukemia-cell apoptosis in vivo, with maximum levels seen at times when we observed peak drug levels of AT-101. Eight patients had completed the study and had full response evaluation at the time of this abstract’s submission. The overall response rate was 38% [CRu (2); PR (1); SD (3); PD (2)]. Four of eight patients (50%) had significant reductions in leukemia cell counts and splenomegaly and 5 of 8 (63%) had reductions in lymphadenopathy. AT-101 in combination with Rituximab has apparent activity in patients with relapsed-refractory high-risk CLL. Additional enrollment is planned using alternate AT-101 schedules in an attempt to increase peak plasma concentrations (and potentially activity) and reduce GI toxicity.

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