Influence of OATP1B1 Function on the Disposition of Sorafenib-β-D-Glucuronide

The oral multikinase inhibitor sorafenib undergoes extensive UGT1A9-mediated formation of sorafenib-β-D-glucuronide (SG). Using transporter-deficient mouse models, it was previously established that SG can be extruded into bile by ABCC2 or follow a liver-to-blood shuttling loop via ABCC3-mediated efflux into the systemic circulation, and subsequent uptake in neighboring hepatocytes by OATP1B-type transporters. Here we evaluated the possibility that this unusual process, called hepatocyte hopping, is also operational in humans and can be modulated through pharmacological inhibition. We found that SG transport by OATP1B1 or murine Oatp1b2 was effectively inhibited by rifampin, and that this agent can significantly increase plasma levels of SG in wildtype mice, but not in Oatp1b2-deficient animals. In human subjects receiving sorafenib, rifampin acutely increased the systemic exposure to SG. Our study emphasizes the need to consider hepatic handling of xenobiotic glucuronides in the design of drug-drug interaction studies of agents that undergo extensive phase II conjugation.

Non-immunosuppressive FTY720-derivative OSU-2S mediates reactive oxygen species-mediated cytotoxicity in canine B-cell lymphoma

OSU-2S is a FTY720 (Fingolimod) derivative that lacks immunosuppressive properties but exhibits strong anti-tumour activity in several haematological and solid tumour models. We have recently shown OSU-2S to mediate potent cytotoxicity in human mantle cell lymphoma cell lines and primary cells. We report here the pre-clinical activity of OSU-2S in spontaneous B-cell lymphoma of dogs which shares many characteristics of human lymphoma. OSU-2S mediated apoptosis in canine B-cell lines and primary B-cell lymphoma cells obtained from spontaneous lymphoma bearing dogs. OSU-2S induced reactive oxygen species (ROS) in canine lymphoma cells and inhibition of ROS partially rescued OSU-2S-mediated cell death. These studies provide a rational basis for the use of spontaneous lymphoma in pet dogs as a preclinical large animal model for the development of OSU-2S as small molecule for treating people and dogs with lymphoma.

Tumor antigen ROR1 targeted drug delivery mediated selective leukemic but not normal B-cell cytotoxicity in chronic lymphocytic leukemia

Selective cytotoxicity to cancer cells without compromising their normal counterparts pose a huge challenge for traditional drug design. Here we developed a tumor antigen targeted delivery of immunonanoparticle carrying a novel non-immunosuppressive FTY720 derivative OSU-2S with potent cytotoxicity against leukemic B cells. OSU-2S induces activation of protein phosphatase 2A, phosphorylation and nuclear translocation of SHP1^S591 and deregulation of multiple cellular processes in chronic lymphocytic leukemia (CLL) resulting in potent cytotoxicity. To preclude OSU-2S mediated effects on these ubiquitous phosphatases in unintended cells and avoid potential adverse effects we developed a OSU-2S targeted delivery immunonanoparticles (2A2-OSU-2S-ILP), that mediated selective cytotoxicity of CLL but not normal B cells through targeting receptor tyrosine kinase ROR1 expressed in leukemic but not normal B cells. Developing a novel spontaneous CLL mouse model expressing human ROR1 (hROR1) in all leukemic B cells, we demonstrate the therapeutic benefit of enhanced survival with 2A2-OSU-2S-ILP in-vivo. The newly developed non-immunosuppressive OSU-2S, its delivery using human CLL directed immunonanoparticles and the novel transgenic mouse model of CLL that expresses hROR1 exclusively in leukemic B cell surface are highly innovative and can be applied to CLL and other ROR1+ malignancies including mantle cell lymphoma and acute lymphoblastic leukemia.

Erlotinib in African Americans with advanced non-small cell lung cancer: a prospective randomized study with genetic and pharmacokinetic analyses

Prospective studies on epidermal growth factor receptor (EGFR) inhibitors in African Americans with non-small cell lung cancer (NSCLC) have not previously been performed. In this phase II randomized study, 55 African Americans with NSCLC received 150 mg/day erlotinib or a body weight-adjusted dose with subsequent escalations to the maximum-allowable dose, 200 mg/day, to achieve rash. Erlotinib and OSI-420 exposures were lower than those observed in previous studies, consistent with CYP3A pharmacogenetics implying higher metabolic activity. Tumor genetics showed only two EGFR mutations, EGFR amplification in 17/47 samples, eight KRAS mutations, and five EML4-ALK translocations. Although absence of rash was associated with shorter time to progression (TTP), disease-control rate, TTP, and 1-year survival were not different between the two dose groups, indicating the dose-to-rash strategy failed to increase clinical benefit. Low incidence of toxicity and low erlotinib exposure suggest standardized and maximum-allowable dosing may be suboptimal in African Americans.

Pharmacokinetic and pharmacodynamic correlations of flavopiridol in the treatment of chronic lymphocytic leukemia

12000

Background: Previous clinical trials with 72-hr and 24-hr infusions of flavopiridol were unsuccessful in producing responses in significant numbers of patients (pts). We utilized pharmacokinetic (PK) modeling to develop a 4.5 hr IV infusion strategy with a 30 mg/m2 loading dose delivered in the first 0.5 hr. and an equal or increased dose delivered over the following 4 hrs to achieve target concentrations of 1.5 to 2.0 μM. This strategy was employed in a phase I study for single agent treatment of CLL. Methods: Plasma samples obtained from pts up to 48 hrs after the start of infusion were extracted and analyzed via LC/MS/MS for parent drug concentration. Non-compartmental analysis was employed in WinNonlin® to analyze flavopiridol plasma concentration vs. time data in 42 patients receiving one or two dosing levels. Patient biographical and response or pharmacodynamic (PD) data, including age, gender, previous treatment, hepatic and renal function, phosphate, albumin and lactate dehydrogenase (LDH) levels, lymph node status, and splenomegaly were collected. In addition, genomic analysis for single nucleotide polymorphisms (SNPs) in flavopiridol metabolizing and transporting enzymes along with correlation of PK, PD and genomic data is underway. Results: Complete PK data has been generated on 41 of the 42 patients treated in cohorts 1 through 3 and is summarized below. 14 of the 42 patients received an escalated dose in cycle 2. As anticipated, the escalated dose achieved concentrations within the targeted window 1.5 to 2.0 μM. This dosing strategy has resulted in response in 45% (19 of 42) of pts treated. Conclusions: PK modeling enabled accurate dose determination for achieving targeted clinical flavopiridol plasma concentrations. Ongoing analysis for correlation of modeled PK parameters with PD and pharmacogenomic data will further enhance our understanding of flavopiridol action in CLL and other malignancies.

[Table: see text]

No significant financial relationships to disclose.

Familial segregation of venous thromboembolism

BACKGROUND

Venous thromboembolism (VTE) is postulated as a complex disease, but the heritability and mode of inheritance are uncertain.

OBJECTIVE

To determine if VTE (i) segregates in families; (ii) is attributable to inheritance, shared environment, or both; and (iii) the possible mode of inheritance.

PATIENTS AND METHODS

In a family-based study of relatives from 751 probands (60% female) with objectively diagnosed VTE (without cancer), we performed complex segregation analyses corrected for mode of ascertainment, considering age-specific, non-gender- and gender-specific liability classes under Mendelian and non-Mendelian assumptions. We tested 12 models categorized into four model sets: (i) sporadic (assumes no genetic effect); (ii) Mendelian inheritance of a major gene (including dominant, additive, recessive or codominant classes); (iii) mixed model (Mendelian inheritance including the same four classes plus the effect of polygenes); and (iv) non-Mendelian.

RESULTS

Among the 16 650 relatives, 753 (48% female) were affected with VTE, of whom 62% were first-degree relatives. The sporadic model was rejected in both non-gender- and gender-specific liability class analyses. Among the remaining gender-specific models, the unrestricted (non-Mendelian) inheritance model was favored with an estimated heritability of 0.52. Among the Mendelian models, the dominant mixed model was preferred, with an estimated heritability and major disease allele frequency of 0.62 and 0.25, respectively, suggesting an effect of several minor genes.

CONCLUSION

A multifactorial non-Mendelian inheritance model was favored as the cause for VTE, while a model postulating a purely environmental cause was rejected. VTE is probably a result of multigenic action as well as environmental exposures.

Delayed emergency department presentation in critically ill patients

OBJECTIVES

To determine the frequency and causes of delayed emergency department presentation in critically ill patients who did not have acute myocardial infarction and to evaluate whether factors such as age, gender, prior medical advice, lack of insurance, or low educational level are associated with delayed presentation.

DESIGN

Prospective, descriptive analysis.

SETTING

Emergency department and medical intensive care unit of an urban county hospital.

PATIENTS

All adult patients admitted from the emergency department to the medical intensive care unit for reasons other than unstable angina, acute myocardial infarction, or stroke over two 9-wk blocks.

INTERVENTIONS

Within 72 hrs of intensive care unit admission, patients or their families were interviewed to determine time elapsed between the onset of symptoms and patient emergency department presentation and to elicit reasons for delays in seeking medical treatment.

MEASUREMENTS AND MAIN RESULTS

We interviewed 155 of 173 (90%) of eligible patients and found that 58% waited >24 hrs before presenting to the emergency department. The most commonly cited primary reason for delays were beliefs that symptoms were not serious enough for emergency care (31%) and that symptoms would resolve spontaneously (29%). Most (55%) sought medical treatment only at the urging of family members or other advocates. Although variables such as lack of insurance and low educational level were not associated with delayed presentation, male gender and having sought medical advice before presenting to the emergency department were significantly associated with delay (p =.036 for each).

CONCLUSIONS

Because of poor understanding of the gravity and natural progression of their symptoms, most critically ill patients waited >24 hrs to present to our emergency department. Education on warning symptom recognition for serious illnesses may be warranted not only for patients themselves but also for family members and caregivers.

Phenomenology and treatment of psychotic disorders in the psychiatric emergency service

The emergency evaluation of a psychotic patient calls on all of the skills of the psychiatrist. The immediate control of dangerous behavior takes place at the same time that clinicians evaluate patients for delirium. A screening physical examination, a brief mental status examination, and a high index of suspicion for medical diseases are essential tools in the first few minutes of a patient's stay in the psychiatric emergency service. Drugs of abuse are often part of a patient's presentation. Here, too, the first task is to rule out delirium, particularly from sedative or alcohol withdrawal. As soon as a patient's condition is stabilized, the psychiatrist should review all of the available information, develop a working diagnosis, and initiate definitive treatment of the presumed disorder. With fewer emergency patients being hospitalized and with shorter lengths of hospital stay, these initial decisions acquire increasing significance for patient outcome.

Staff training decreases use of seclusion and restraint in an acute psychiatric hospital

Rates of seclusion and restraint in an urban psychiatric hospital were compared during the 12-month periods before and after implementing the recommendations of a multidisciplinary quality improvement work-group convened to reduce the hospital's use of physical containment. Interventions included a mandatory staff training session on the management of assaultive behavior, weekly discussion items during team meetings for each local ward, and hospital-wide publicity charting the ongoing progress of the effort. Total annual rates of restraint dropped 13.8%. The average duration of restraint per admission decreased 54.6%. Staff injuries were reduced by 18.8% during the study period.