TAK-285, a Novel HER2/EGFR Inhibitor, Penetrates the CNS in Rats with an Intact Blood Brain Barrier (BBB)

Background: Approximately one third of patients with HER2-overexpressing (HER2+) metastatic breast cancer develop brain metastases. Treatment options for patients whose brain metastases have progressed after radiotherapy are urgently needed. The currently approved HER2-targeted therapies, trastuzumab and lapatinib, have generally shown limited activity against brain metastases, likely due to the limited brain penetration of these drugs. Brain penetration is mediated by multiple factors including drug permeability, tissue binding, and the expression of efflux transporters (P-gp and BCRP) and their interactions with the drug. TAK-285 is a novel, orally active, dual HER2/EGFR inhibitor currently under clinical development. In this nonclinical work, we evaluated the permeability, interactions with efflux transporters, and brain penetration of TAK-285, along with lapatinib and neratinib, using in vitro and animal models.Material and Methods: The first study evaluated the permeability of TAK-285, lapatinib, and neratinib and their interactions with efflux transporters using the Caco-2 cell monolayer system in the absence or presence of efflux pump inhibitors. The second study evaluated brain penetration of TAK-285, lapatinib and neratinib after a single oral administration in rats with an intact BBB.Results: In the Caco-2 cell model, TAK-285 showed high permeability with an efflux ratio of 1.7, indicating it is not a substrate for efflux pumps. The efflux pump inhibitors LY335979 (an inhibitor of P-gp), Ko143 (an inhibitor of BCRP), and GF120918 (an inhibitor of BCRP and P-gp) had no marked effect on the efflux ratio of TAK-285, further confirming that TAK-285 is not a substrate for P-gp and BCRP. Lapatinib and neratinib showed low to medium permeability and appeared to be substrates for P-gp/BCRP in this testing system. In the rat brain penetration study, the brain-to-plasma AUC ratio for total (free and bound) TAK-285, lapatinib, and neratinib was 0.202, 0.0243, and 0.0263, respectively.Discussion: These nonclinical studies showed that, unlike lapatinib and neratinib, TAK-285 is not a substrate for the efflux transporters, P-gp and BCRP. Based on published information, all of the approved receptor tyrosine kinase inhibitors are substrates for efflux transporters. Additionally, in rats with an intact BBB, the brain-to-plasma AUC ratio for TAK-285 was substantially higher than that of lapatinib and neratinib. The AUC ratios observed in this study for lapatinib and neratinib are similar to the proportion of blood volume in the rat brain (ie, outside the CNS) relative to the total rat brain volume. This suggests the actual brain-to-plasma AUC ratio for TAK-285 in rats may be much greater than 8-fold of that of lapatinib and neratinib calculated based on these measured AUC ratios. Consequently, TAK-285 may have a unique role in the treatment of brain lesions in patients with HER2- or EGFR-dependent tumors. Furthermore, TAK-285 may not be subject to drug resistance conferred by efflux transporters.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 5098.

Model-based sensorimotor integration for multi-joint control: development of a virtual arm model

An integrated, sensorimotor virtual arm (VA) model has been developed and validated for simulation studies of control of human arm movements. Realistic anatomical features of shoulder, elbow and forearm joints were captured with a graphic modeling environment, SIMM. The model included 15 musculotendon elements acting at the shoulder, elbow and forearm. Muscle actions on joints were evaluated by SIMM generated moment arms that were matched to experimentally measured profiles. The Virtual Muscle (VM) model contained appropriate admixture of slow and fast twitch fibers with realistic physiological properties for force production. A realistic spindle model was embedded in each VM with inputs of fascicle length, gamma static (gamma(stat)) and dynamic (gamma(dyn)) controls and outputs of primary (I(a)) and secondary (II) afferents. A piecewise linear model of Golgi Tendon Organ (GTO) represented the ensemble sampling (I(b)) of the total muscle force at the tendon. All model components were integrated into a Simulink block using a special software tool. The complete VA model was validated with open-loop simulation at discrete hand positions within the full range of alpha and gamma drives to extrafusal and intrafusal muscle fibers. The model behaviors were consistent with a wide variety of physiological phenomena. Spindle afferents were effectively modulated by fusimotor drives and hand positions of the arm. These simulations validated the VA model as a computational tool for studying arm movement control. The VA model is available to researchers at website http://pt.usc.edu/cel .

Inositol lipids and phosphates in the proliferation and differentiation of lymphocytes and myeloid cells

It is established that receptor-stimulated hydrolysis of phosphatidylinositol 4,5-bisphosphate is an essential signalling reaction in the responses of many haemopoietic cells to stimuli: examples include platelet activation, antigen-driven initiation of cell proliferation in mature B and T lymphocytes and histamine release by mast cells, and chemotaxis and oxygen radical generation by neutrophils. However, the roles of inositol lipids and phosphates in the development of haemopoietic and immune cells are less well understood. This paper discusses three such situations: the sequential employment of phosphatidylinositol 4,5-bisphosphate hydrolysis and cyclic AMP accumulation as two signals essential to the action of the B lymphocyte-stimulatory cytokine interleukin 4; the involvement of antigen receptor-triggered inositol lipid hydrolysis in apoptotic elimination of immature anti-self T lymphocytes in the fetal mouse thymus; and the possible role of changes in the levels of abundant inositol polyphosphates in the differentiation of HL-60 promyelocytic cells and of normal human myeloid blast cells.

Modeling spinal sensorimotor control for reach task

The spinal sensorimotor control system executes movement instructions from the central controller in the brain that plans the task in terms of global requirements. Spinal circuits serve as a local regulator that tunes the neuromuscular apparatus to an optimal state for task execution. We hypothesize that reach tasks are controlled by a set of feedforward and feedback descending commands for trajectory and final posture, respectively. This paper presents the use of physiologically realistic models of the spinal sensorimotor system to demonstrate the feasibility of such dual control for reaching movements.

Phase I-II trial of daily thalidomide in combination with docetaxel in patients with relapsed non-small cell lung cancer: A final analysis

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Background: Recent studies have shown that inhibition of vascular endothelium growth factor (VEGF) in combination with chemotherapy can improve the antitumor efficacy of chemotherapy in NSCLC. This study tested the effectivness and toxicity of thalidomide (an inhibitor of VEGF) combined with docetaxel as second-line therapy for progressive NSCLC. Methods: Patients(pts) with recurrent/progressive NSCLC, prior chemotherapy, measurable/evaluable disease, ECOG performance status (PS) 0–2 and adequate hematologic, renal and hepatic function were enrolled. Pts with uncontrolled CNS disease or hypercoagulable state were excluded. Doxetaxel 75 mg/M2 was administered every 3 weeks (maximum of 8 cycles). Thalidomide was administered orally at a starting dose of 50 mg daily escalated by 50 mg every 3 weeks to a maximum dose of 200mg day and continued until disease progression, dose limiting toxicity, or completion of chemotherapy. Primary end-point was overall survival (OS), secondary end points were time to disease progression(TTP) by Kaplan Meyer method and response rate (RECIST criteria). Results: Of 28 enrolled patients, 26 were eligible for treatment and 25 were evaluable for disease progression and survival. For evaluable pts: mean PS = 1, median age 64.5 years, median number of prior chemotherapy regimens + 1.2. Response rate was 19.1% (1 complete response, 4 partial responses). Stable disease was observed in 9 patients (34.6%). TTP was 2.7 months (95% confidence interval [CI] 2.1–5.0+): median OS was 5.4 months (95% CI 3.1–9.3+). One episode each of febrile neutropenia requiring hospitalization and pulmonary embolism was observed. No grade 3–4 neuropathy was shown. Nonhematologic adverse events included constipation, alopecia, nausea and anorexia. Conclusions: These data suggest thalidomide in doses of 200mg/ day may be combined with docetaxel 75 mg/m2 every 3 weeks in the second line treatment of NSCLC. The response rate, TTP and OS compare favorably with previously reported studies with docetaxel in this population.

No significant financial relationships to disclose.

Outcomes of Patients With Rejection Post–Polyomavirus Nephropathy

INTRODUCTION

We sought to determine the effects of rejection in renal transplant recipients with polyomavirus nephropathy (PVN).

METHODS

SCr, biopsy findings, BKV serum and urine loads (Taqman PCR), and BKV antibody titers (HA inhibition assay) were analyzed by two-sample median tests and z tests in 11 patients with median follow-up of 7.3 (2.0 to 31.5) months post-PVN. All patients underwent immunosuppression reduction (ISR) as PVN treatment.

RESULTS

Post-PVN, 3 (27%) patients had five rejection episodes, with 80% being mild. Median time to rejection was 18 (2 to 60) weeks. One hundred percent of patients who experienced post-PVN rejection also experienced rejection pre-PVN. Rejection episode treatments consisted of: none in one, increased tacrolimus in two, IVIG in one, IVIG and increased tacrolimus in one. Median viral loads in patients with post-PVN rejection versus those without rejection were not different in serum (2.01 x 10(4) vs 9.00 x 10(4) BKV copies/mL; P = .22) or urine (5.37 x 10(5) vs 8.93 x 10(6) BKV copies/mL; P = .28). Median BKV antibody titers were slightly lower (16384 vs 32768 HA units; P = .02) and median SCr values were significantly higher (2.7 vs 1.9 mg/dL, P = .0003) in patients who had experienced post-PVN rejection. Graft losses occurred in one rejection-free patient (chronic allograft nephropathy) and in one patient who experienced multiple acute rejection episodes, humoral rejection, and worsening PVN.

CONCLUSIONS

Patients who experience rejection prior to PVN are at high risk of developing rejection post-ISR and post-PVN; however, low graft loss rates may still be achieved.

Detection of JC virus-specific cytotoxic T lymphocytes in healthy individuals

The polyomavirus JC (JCV) infects 85% of healthy individuals, and its reactivation in a limited number of immunosuppressed people causes progressive multifocal leukoencephalopathy (PML), a severe demyelinating disease of the central nervous system. We hypothesized that JCV-specific cytotoxic T lymphocytes (CTLs) might control JCV replication in healthy individuals, blocking the evolution of PML. Using 51Cr release and tetramer staining assays, we show that 8 of 11 HLA-A*0201+ healthy subjects (73%) harbor detectable JCV-specific CD8+ CTLs that recognize one or two epitopes of JCV VP1 protein, the HLA-A*0201-restricted VP1p36 and VPp1100 epitopes. We determined that the frequency of JCV VP1 epitope-specific CTLs varied from less than 1/100,000 to 1/2,494 peripheral blood mononuclear cells. More individuals had JCV VP1-specific than cytomegalovirus-specific CTLs (8 of 11 subjects [73%] versus 2 of 10 subjects [20%], respectively). These results show that a CD8+-T-cell response against JCV is commonly found in immunocompetent people and suggest that these cells might protect against the development of PML.

Assessment of airway function in young children with asthma: comparison of spirometry, interrupter technique, and tidal flow by inductance plethsmography

The assessment of airway function in young children requires adaptation of techniques designed for adults and/or application of techniques that do not require complex respiratory maneuvers. We sought to assess two methods of measuring airway function: time to peak expiratory flows as a ratio of expiratory time (T(PTEF)/T(E)), derived from respiratory inductance plethysmography, and total respiratory resistance by the interrupter technique (Rint), both obtained during quiet tidal breathing. Both techniques were referenced to FEV1 and flow at 50% expired volume (FEF50) from conventional spirometry in 30 children aged 4-8 years (median age, 6.9; range, 4.5-8.5 years) with a physician diagnosis of asthma and who were able to perform FEV1 with a repeatability of at least 8%. T(PTEF)/T(E) and Rint were performed in random order followed by spirometry, in order to reduce the possible effects of pulmonary stretch on tidal breathing measures. Coefficients of variation (CV) and mean absolute change/baseline standard deviation were derived for each measurement. Baseline FEV1 did not correlate significantly with T(PTEF)/T(E) (r = 0.025), but did correlate with Rint (r = 0.737, P < 0.001); respective relationships for change after bronchodilator were r = 0.09 (ns) and r = 0.64 (P < 0.001). FEF50 also correlated significantly with Rint (R = 0.769, P < 0.001) but not with T(PTEF)/T(E). FEV1 and FEF50 both increased postbronchodilator, with respective mean changes of 11.4% and 28% (P < 0.001), while Rint decreased by 24.3% (P < 0.001). No significant changes were noted for T(PTEF)/T(E). T(PTEF)/T(E) derived from inductance plethysmography does not detect mild airway obstruction or modest changes in airway caliber following bronchodilator in young children with asthma. The interrupter technique may have a role in assessing baseline airway function and response to therapy in children unable to perform reliable spirometry, and/or when the investigator wishes to avoid the possible influence of forced maneuvers on airway tone.

A fresh perspective on a rank issue: pupils' accounts of staff enforcement of smoking restrictions

Evidence on the effectiveness of school-based smoking restrictions on reducing pupil smoking rates is mixed. So far, the effect of such policies has only been considered using quantitative methods and 'level of enforcement' has primarily been measured according to data collected from staff. This qualitative study is based on data collected during 25 discussion groups held with 13-year-old pupils concerning whether and how staff in their school addressed pupil smoking. Groups were conducted in two schools. Both served relatively deprived communities but varied in their pupil smoking rates. Pupils made reference to members of the Senior Management Team, teaching and non-teaching staff. They mentioned a range of possible staff reactions and discussed what factors they felt influenced how staff responded. It appeared that a more proactive, firm line was being taken in the 'high' than in the 'low' smoking school.

Butt in, butt out: pupils' views on the extent to which staff could and should enforce smoking restrictions

Schools which enforce a no-smoking policy may experience lower rates of pupil smoking. Little is known, however, about how young people view such restrictions and it has been argued that smoking bans might actually encourage adolescent smoking. This paper presents pupils' views on the extent to which staff could, and should, enforce smoking restrictions. Twenty-five single-sex discussion groups were held with 13-year-old pupils who had been purposively selected from two Scottish secondary schools. Both schools served relatively deprived communities and ostensibly had no-smoking policies, but varied in their pupil smoking rates. The pupils' accounts suggested that staff enforcement could interrupt pupil smoking and discourage smoking on school premises, but did not affect whether or not they actually smoked. Pupils viewed staff efforts as ineffective and felt staff did not always have the authority or status needed to enforce a ban. Differences were found between the schools, but these did not explain the variation in their smoking profiles.

School differences in pupil smoking: a consequence of a trade-off between health and education agendas?

Current policy documents stress that raising standards in education and health are inextricably linked, with schools identified as well placed to advance both agendas. This paper considers these assumptions in the light of data derived from 27 staff interviews conducted in two secondary schools. These schools served relatively disadvantaged communities, but differed in their pupil smoking rates with one school being 'high-smoking', the other 'low-smoking'. It explores whether this difference reflects the differential emphasis placed by each school on education or health. Analysis reveals that the 'low-smoking' school subscribes to holistic values and operates according to a child-centred bottom-up philosophy offering a differentiated programme of pupil support contingent on needs. In contrast, the 'high-smoking' school maintains a narrow focus on educational outcomes, and its high expectations are viewed as running counter to those held by pupils and parents. The contrasting school philosophies bring different unintended consequences. The holistic focus of the low-smoking school is associated with tempered educational expectations, thus conflicting with recommendations in education policies. The singular education focus of the high-smoking school leaves little room for a health agenda, and can overlook and disenfranchise the educationally disinclined. The school systems' impact on pupil engagement may explain their different smoking rates.

Ifs, maybes and butts: factors influencing staff enforcement of pupil smoking restrictions

Levels of pupil smoking are reported to be associated with the extent to which school staff consistently enforce smoking restrictions. Little is known, however, about factors which might motivate or discourage staff from doing so. Following analysis of interviews conducted with 27 members of school personnel purposively selected from two Scottish secondary schools serving relatively deprived communities, this paper identifies various issues that hinder staff intervention when confronted with pupil smoking. Both schools had no-smoking policies. In each, staff assumed or understood that smoking within the buildings was forbidden, yet were unsure about how far the bans extended. While the risk of fire in the school buildings prompted staff to intervene when smoking was witnessed indoors, where this risk was absent, decisions were largely context dependent or motivated by personal and professional values. Concerns about staff-pupil relationships, attention to pupils' wider welfare, lack of authority and staff levels of discomfort were salient issues inhibiting intervention. Implications for smoking policies and their enforcement are discussed. The concept of the Health Promoting School is considered in the light of the findings and inherent tensions highlighted.