Phase I/IIa trial of the mammalian target of rapamycin inhibitor ridaforolimus (AP23573; MK-8669) administered orally in patients with refractory or advanced malignancies and sarcoma.

BACKGROUND: Ridaforolimus is an inhibitor of mTOR with evidence of antitumor activity in an I.V. formulation. This multicenter, open-label, 3 + 3 design nonrandomized, dose-escalation, phase I/IIa trial was conducted to determine the safety, pharmacokinetic (PK) and pharmacodynamic parameters, maximum tolerated dose, and antitumor activity of oral ridaforolimus. PATIENTS AND METHODS: Patients with metastatic or unresectable solid tumors refractory to therapy were eligible. Seven different continuous and intermittent dosing regimens were examined. RESULTS: One hundred and forty-seven patients were enrolled in this study among which 85 were patients with sarcoma. Stomatitis was the most common DLT observed. The dosing regimen, 40 mg QD × 5 days/week, provided the best combination of cumulative dose, dose density, and cumulative exposure, and was the recommended dosing regimen for subsequent clinical development. PK was nonlinear, with less than proportional increases in day-1 blood AUC0-∞ and Cmax, particularly with doses >40 mg. The terminal half-life estimate of ridaforolimus (QD × 5 40 mg) was 42.0 h, and the mean half-life ∼30-60 h. The clinical benefit rate, (complete response, partial response, or stable disease for ≥4 months was 24.5% for all patients and 27.1% for patients with sarcoma. CONCLUSION: Oral ridaforolimus had an acceptable safety profile and exhibited antitumor activity in patients with sarcoma and other malignancies. ClinicalTrials.gov Identifier NCT00112372.

Optimal modeling for phase I design of a two drug combination-results of a phase I study of cisplatin with 9-nitrocamptothecin.

Combination of platinum with topoisomerase-I inhibitors are synergistic. The objectives of this study were to determine MTD range and toxicity profile of combinations of oral 9-nitrocamptothecin (9NC) and intravenous cisplatin in patients with refractory solid tumors. Each course was 28 days starting on day 1 with cisplatin, and then 9NC daily for 5 days/week for three weeks. A new two arm crossing design was created: patients in arm 1 were treated with at the single agent recommended dose of cisplatin (50 mg/m(2)), and increasing doses of 9NC and in arm 2 with the single agent recommended dose of 9NC (1.5 mg/day) and increasing dose of cisplatin. Once a dose limiting toxicity was observed, the dose of the escalated drug was decreased by one level, and the fixed-dose drug was then escalated. A 3 + 3 design was used. Eligibility criteria were standard for a phase I trial. Pharmacokinetics was performed. Eighteen patients were treated on Arm 1, 3 at the crossing level, and 33 on Arm 2. Dose limiting toxicities were gastrointestinal at the crossing dose level. After crossing, prolonged grade 3 thrombocytopenia was the DLT in arm 1, and grade 4 neutropenia in Arm 2. Only one patient with ovarian cancer had a partial remission, and 12 patients had disease stabilization (24% of clinical benefit). A Bayesian optimal dose finding was tested post-facto. The recommended doses for phase II studies by the 3 + 3 design are cisplatin 60 mg/m(2) and 9NC 1.25 mg/day and cisplatin 40 mg/m(2) and 9NC 2.0 mg/day. The Bayesian optimal dose finding suggested a different solution, closest to that of the latter dosing which may be less toxic.

Post-acute dispositions of older adults hospitalized for depression.

This study addressed factors associated with six-month post-acute dispositions (continuous community stay, medical hospitalization, psychiatric rehospitalization, nursing home placement, death) for older adults hospitalized for depression and discharged to the community. The sample included 199 older adults; and data were collected via medical records, interviews with discharge planners, patients, and family members. Over half of the sample remained in the community throughout the observation period; 23% experienced psychiatric re-admission and 10% entered a nursing home. Several factors associated with nursing home placement were identified: less improvement in depression during the hospitalization, lower Global Assessment of Functioning (GAF) scores at discharge; and less mental health service use in the post-acute period. Those at higher risk of psychiatric re-admission had more previous psychiatric hospitalizations and were marginally more likely to be married and have lower Brief Psychiatric Rating Scale (BPRS) scores at discharge. Differentiating those at risk for nursing home placement may be easier than differentiating those at risk of psychiatric readmission.

A multicenter, randomized, placebo controlled, multiple-dose, safety and pharmacokinetic study of AIT-082 (Neotrofin) in mild Alzheimer's disease patients.

A phase 1, randomized, double-blind, placebo-controlled, dose escalation study of the purine derivative, AIT-082 (Neotrofin, NeoTherapeutics) was conducted in mild Alzheimer's disease (AD) patients to evaluate multiple-dose safety, tolerability, and pharmacokinetics. Possible short-term effects of AIT-082 on cognition and memory were preliminarily investigated. AIT-082 is currently being developed as a potential treatment for Alzheimer's disease and other neurological disorders. Pre-clinical studies indicate that AIT-082 has memory enhancing properties, stimulates neuritogenesis and the production of neurotrophic factors. Patients received an oral dose of AIT-082 or placebo daily for one week. Thirty-six AD patients were divided into three dose cohorts; each dose cohort consisted of twelve patients with 8 patients randomized to AIT-082 and 4 to placebo. The 3 doses of AIT-082 evaluated in this study were 100 mg/day, 500 mg/day, and 2,000 mg/day. There were no serious adverse events at any dose and the drug was well tolerated without significant side effects. AIT-082 was orally and rapidly absorbed, resulting in peak serum concentrations within 2 hours with an elimination half-life of approximately 20 hours. Higher doses resulted in corresponding increases in peak concentrations and areas under the curve (AUC). There was an approximate 2-fold accumulation in AIT-082 with daily dosing (as reflected by the AUC) at steady state. There were no significant differences by treatment arm on the clinical or neuropsychological evaluations. AIT-082 was rapidly absorbed by the oral route with a half-life suitable for dosing once or twice daily. No problems with tolerability or safety were found. AIT-082 appears suitable for testing in larger clinical trials for the treatment of AD and other neurologic disorders.

Ubiquitin/26S proteasome-mediated degradation of topoisomerase I as a resistance mechanism to camptothecin in tumor cells.

Camptothecin (CPT) induces down-regulation of topoisomerase I (TOP1) via an ubiquitin/26S proteasome pathway. Studies using a panel of breast and colorectal cancer cell lines as well as primary nontransformed and oncogene-transformed cells have demonstrated that CPT-induced down-regulation exhibits a high degree of heterogeneity. In general, nontransformed cells are much more proficient in CPT-induced TOP1 down-regulation than their transformed counterparts. Among the breast and colorectal cancer cell lines, there was a general correlation between the extent of CPT-induced TOP1 down-regulation and CPT resistance. The breast cancer cell line ZR-75-1, the most sensitive to CPT, was completely defective in CPT-induced TOP1 down-regulation, whereas the breast cancer cell line BT474, the least sensitive to CPT, exhibited effective CPT-induced TOP1 down-regulation. The 26S proteasome inhibitor MG132 was shown to inhibit CPT-induced down-regulation of TOP1 in BT474 cells and selectively sensitized BT474 but not ZR-75-1 cells to CPT-induced cytotoxicity and apoptosis. In the aggregate, these results suggest that CPT-induced down-regulation of TOP1 could be an important parameter for determining CPT sensitivity/resistance in tumor cells. Analysis of the levels of TOP1 cleavable complexes, SUMO-1-TOP1 conjugates, and ubiquitin-TOP1 conjugates in ZR-75-1 and BT474 cells has suggested that the heterogeneity of CPT-induced down-regulation of TOP1 in tumor cells is at least in part attributable to altered regulation of a process(es) downstream from the TOP1 cleavable complex.

Clinically significant depressive symptoms and very mild to mild dementia of the Alzheimer type.

OBJECTIVE: To compare depressive symptoms reported by persons with very mild or mild dementia of the Alzheimer type (DAT) with those reported for the person by a collateral source. DESIGN: Cross-sectional evaluation. SETTING: Washington University Alzheimer's Disease Research Center. PARTICIPANTS: Consecutive series of elderly volunteers (n = 156) enrolled in longitudinal studies with a Clinical Dementia Rating (CDR) of 0.5 (very mild) or 1 (mild). Twenty-one per cent (n = 33) exhibited clinically significant depressive symptoms for which treatment was recommended. MAIN OUTCOME MEASURES: Presence and frequency of DSM-IV depressive symptoms within the last year and last month reported by the participant or collateral source as ascertained by clinical examination and structured interviews. RESULTS: Collateral source information is essential in diagnosing clinically significant depressive symptoms. The Geriatric Depression Scale scores correlate with participant information only and therefore may substantially underestimate depression. Depressive symptoms fluctuate in individuals with DAT. The most consistent depressive symptoms are depressed mood, fatigue and indecision. CONCLUSIONS: Clinically significant depressive symptoms may be common in individuals with very mild or mild DAT, although they may fluctuate. Information from both a knowledgeable collateral source and the participant is important for detection of depressive symptoms.

Mild cognitive impairment represents early-stage Alzheimer disease.

BACKGROUND: Mild cognitive impairment (MCI) is considered to be a transitional stage between aging and Alzheimer disease (AD). OBJECTIVE: To determine whether MCI represents early-stage AD by examining its natural history and neuropathologic basis. DESIGN: A prospective clinical and psychometric study of community-living elderly volunteers, both nondemented and minimally cognitively impaired, followed up for up to 9.5 years. Neuropathologic examinations were performed on participants who had undergone autopsy. SETTING: An AD research center. PARTICIPANTS: All participants enrolled between July 1990 and June 1997 with Clinical Dementia Rating (CDR) scores of 0 (cognitively healthy; n = 177; mean age, 78.9 years) or 0.5 (equivalent to MCI; n = 277; mean age, 76.9 years). Based on the degree of clinical confidence that MCI represented dementia of the Alzheimer type (DAT), 3 subgroups of individuals with CDR scores of 0.5 were identified: CDR 0.5/DAT, CDR 0.5/incipient DAT, and CDR 0.5/uncertain dementia. MAIN OUTCOME MEASURE: Progression to the stage of CDR 1, which characterizes mild definite DAT. RESULTS: Survival analysis showed that 100% of CDR 0.5/DAT participants progressed to greater dementia severity over a 9.5-year period. At 5 years, rates of progression to a score of CDR 1 (or greater) for DAT were 60.5% (95% confidence interval [CI], 50.2%-70.8%) for the CDR 0.5/DAT group, 35.7% (95% CI, 21.0%-50.3%) for the CDR 0.5/incipient DAT group, 19.9% (95% CI, 8.0%-31.8%) for the CDR 0.5/uncertain dementia group, and 6.8% (95% CI, 2.2%-11.3%) for CDR 0/controls. Progression to greater dementia severity correlated with degree of cognitive impairment at baseline. Twenty-four of the 25 participants with scores of CDR 0.5 had a neuropathologic dementing disorder, which was AD in 21 (84%). CONCLUSIONS: Individuals currently characterized as having MCI progress steadily to greater stages of dementia severity at rates dependent on the level of cognitive impairment at entry and they almost always have the neuropathologic features of AD. We conclude that MCI generally represents early-stage AD.

Absence of cognitive impairment or decline in preclinical Alzheimer's disease.

OBJECTIVE: To determine whether clinically nondemented elderly individuals with pathologically confirmed preclinical AD are characterized by cognitive decline as measured by psychometric tests before death. METHODS: Psychometric performance was examined retrospectively in 14 individuals who were nondemented at time of death and grouped in accordance with their neuropathologic findings: 1) Healthy brain (n = 9) was characterized by the absence of senile plaques or by only patchy neocortical deposits of plaques; 2) preclinical AD (n = 5) was characterized by neuritic and diffuse plaques distributed throughout the neocortex. All individuals showed neurofibrillary pathologic change in medial temporal lobe structures. For comparison, we also evaluated 10 individuals who died in the earliest symptomatic stage of dementia of the Alzheimer type (DAT). All individuals had been assessed by clinical and psychometric measures during life. The psychometric measures yielded a standardized factor score that represented global cognitive performance. RESULTS: At the last assessment before death, individuals with very mild DAT were impaired on the factor score and on individual psychometric measures with respect to the nondemented individuals. Those nondemented individuals with preclinical AD did not differ in performance from those with healthy brains. For individuals with at least three psychometric assessments during life, there was no decline in performance for either those with healthy brains (n = 5) or preclinical AD (n = 3), although decline was evident for very mild DAT individuals (n = 5). CONCLUSIONS: Pathologically confirmed preclinical AD is not associated with cognitive impairment or decline, even on measures shown to be sensitive to very mild DAT.

Increased neocortical neurofibrillary tangle density in subjects with Alzheimer disease and psychosis.

BACKGROUND: Psychosis is common in patients with Alzheimer disease. While the relationship between psychosis and clinical variables has been examined frequently, few studies have examined the relationship between psychosis and the 2 major neuropathological hallmarks of Alzheimer disease: neurofibrillary tangles and senile plaques. We characterized the occurrence of psychosis in relation to dementia severity and determined if subjects with Alzheimer disease and psychosis had a greater neurofibrillary tangle or senile plaque burden than subjects with Alzheimer disease and no psychosis. METHODS: One hundred nine subjects with Alzheimer disease were followed longitudinally with semistructured assessments in order to assign a Clinical Dementia Rating and determine whether psychosis was present. After the subjects died, their brains were obtained for histological examination. Analysis of variance was used to compare the densities of neurofibrillary tangles, total senile plaques, and cored senile plaques in subjects with psychosis vs subjects without psychosis, in several neocortical regions, the hippocampus, and the entorhinal cortex. RESULTS: Psychosis occurred commonly in Alzheimer disease, affecting 63% of subjects. The frequency of psychosis increased with increasing dementia severity. More importantly, we found that subjects with psychosis had a 2.3-fold (95% confidence interval, 1.2-3.9) greater density of neocortical neurofibrillary tangles than did subjects without psychosis. The increase was independent of dementia severity. No similar relationship with psychosis was seen for total senile plaques or cored senile plaques. CONCLUSIONS: The increase in psychosis frequency that occurs with the progression of dementia severity and the independent association between psychosis and neurofibrillary tangle density suggest the possibility that some common underlying process or processes specific to Alzheimer disease may regulate both phenomena. Arch Gen Psychiatry. 2000;57:1165-1173.

Role for nucleolin/Nsr1 in the cellular localization of topoisomerase I.

Nucleolin functions in ribosome biogenesis and contains an acidic N terminus that binds nuclear localization sequences. In previous work we showed that human nucleolin associates with the N-terminal region of human topoisomerase I (Top1). We have now mapped the topoisomerase I interaction domain of nucleolin to the N-terminal 225 amino acids. We also show that the Saccharomyces cerevisiae nucleolin ortholog, Nsr1p, physically interacts with yeast topoisomerase I, yTop1p. Studies of isogenic NSR1(+) and Deltansr1 strains indicate that NSR1 is important in determining the cellular localization of yTop1p. Moreover, deletion of NSR1 reduces sensitivity to camptothecin, an antineoplastic topoisomerase I inhibitor. By contrast, Deltansr1 cells are hypersensitive to the topoisomerase II-targeting drug amsacrine. These findings indicate that nucleolin/Nsr1 is involved in the cellular localization of Top1 and that this localization may be important in determining sensitivity to drugs that target topoisomerases.

Mechanisms of resistance to camptothecins.

Camptothecins are broad-spectrum anticancer drugs that specifically target DNA topoisomerase I. Although the availability of camptothecins has had a significant impact on cancer therapeutics, de novo or acquired clinical resistance to camptothecins is common. Studies of camptothecin resistance using yeast and mammalian cell culture models suggest three general mechanisms of resistance: (1) reduced cellular accumulation of camptothecins, (2) alteration in the structure or location of topoisomerase I, and (3) alterations in the cellular response to camptothecin-DNA-ternary complex formation. The relevance of these mechanisms to clinical drug resistance is not yet known, but evaluation of these models in clinical specimens should enhance the use of camptothecins both as single agents and in combination with other anticancer drugs.

Effects of mutations in the F361 to R364 region of topoisomerase I (Topo I), in the presence and absence of 9-aminocamptothecin, on the Topo I-DNA interaction.

Steady-state levels and rates of DNA binding and release of wild-type and mutant topoisomerase I (Topo I) proteins were quantified by surface plasmon resonance analysis. The proteins were constructed and expressed as GST fusion proteins. The Topo I mutations analyzed were F361S, R362L and R364G, all altering a highly conserved region of wild-type eukaryotic Topo I. The R362L and R364G mutations resulted in much lower steady-state levels of DNA binding than wild-type. This was due to a large increase in the k(d). The F361S mutation increased the steady-state levels of the protein-DNA interaction by increasing the k(a) 2-fold, while having little effect on the k(d). The F361S mutation has been shown to confer resistance to camptothecin and its analogs. The camptothecin analog 9-aminocamptothecin decreased greatly the overall k(d) of the wild-type Topo I, but had little effect on the F361S mutant. Both the wild-type and the F361S mutant exhibited decreased steady-state levels in the presence of the drug, and this was attributable to decreased association.

In vitro activation of irinotecan to SN-38 by human liver and intestine.

BACKGROUND: Irinotecan (CPT-11) is hydrolyzed by carboxyl esterase to the active metabolite SN-38 and oral irinotecan could undergo intestinal and hepatic activation. MATERNALS AND METHODS: Irinotecan was incubated with S9 fractions of human liver and intestinal tissues and the specific activity was determined based on the formation rate of SN-38. RESULTS: Irinotecan was hydrolyzed to SN-38 by hepatic and intestinal S9 fractions with mean (+/- SD) specific activities (pmoles/min/mg) of: liver (8.57 +/- 10.4, n = 8), duodenum (5.06 +/- 3.7, n = 4), jejunum (6.44 +/- 2.8, n = 5), ileum (4.81 +/- 2.4, n = 5), colon (1.93 +/- 1.5, n = 6) and rectum (0.82, n = 1). When incubated with S9 fractions obtained from tumor tissues, there appeared to be a decrease in SN-38 formation compared to matched normal liver and colon tissues. CONCLUSION: Irinotecan undergoes conversion to its active metabolite in human intestinal S9 fractions and there is variability in the extent of SN-38 formation. The localized intestinal activation of irinotecan to SN-38 may provide a rationale for the development of oral irinotecan for gastrointestinal malignancies but could also cause mucosal damage leading to toxicity.

Interaction between human topoisomerase I and a novel RING finger/arginine-serine protein.

The N-terminus of human topoisomerase I participates in the binding of this enzyme to helicases and other proteins. Using the N-terminal 250 amino acids of human topoisomerase I and a yeast two-hybrid/ in vitro binding screen, a novel arginine-serine-rich peptide was identified as a human topoisomerase I-binding protein. The corresponding full-length protein, named topors, contains a consensus RING zinc finger domain and nuclear localization signals in addition to the arginine-serine-rich region. The RING finger domain of topors is homologous to a similar domain in a family of viral proteins that are involved in the regulation of viral transcription. When expressed in HeLa cells as a green fluorescent protein fusion, topors localizes in the nucleus in a punctate pattern and co-immunoprecipitates with topoisomerase I. These data suggest that topors is involved in trans-cription, possibly recruiting topoisomerase I to RNA polymerase II transcriptional complexes.

The quality of psychiatric residency : the assessment of programs and options for distributing psychiatric residents in the service of health care reform.

Recent health care reform initiatives proposed training fewer medical specialists, including psychiatrists, and determining the size and location of training programs via centralized regulatory mechanisms. Facing such potential future developments, the American Association of Directors of Psychiatric Residency Training appointed a Task Force on the Quality of Residency Programs to develop informed recommendations for the field. This paper describes the Task Force's considerations and recommendations concerning how the least damaging and most effective decisions could be made regarding the distribution of residency positions, program size, and the future funding of training stipends. The recommendations emphasize voluntary decisions, feedback from local and regional stakeholders regarding perceived needs and demands for psychiatrists, and Federal or regional funding of postgraduate training stipends that are not primarily tied to providing clinical services.

Selective cytotoxicity of topoisomerase-directed protoberberines against glioblastoma cells.

Protoberberines are a new class of organic cations that are dual poisons of topoisomerases I and II. Certain protoberberines exhibit greater in vitro cytotoxicity against cell lines derived from solid tumors than from leukemias. Using a group of seventeen different protoberberine analogs, the structural basis for selective cytotoxicity toward sensitive SF-268 glioblastoma cells as compared with resistant RPMI 8402 lymphoblast cells was explored. The selective cytotoxicity is associated with the presence of an imminium ion and other structural features of protoberberines, and is not shared by drugs such as camptothecin, doxorubicin, vinblastine, and etoposide, which are either equally or more cytotoxic against RPMI 8402 cells than SF-268 cells. The selective cytotoxicity of protoberberines against SF-268 over RPMI 8402 cells is not due to differences in topoisomerase levels or known drug efflux systems such as multidrug resistance (MDR1) and multidrug-resistance protein (MRP). Comparative in vitro studies of the accumulation of coralyne, a fluorescent protoberberine, into sensitive and resistant cells demonstrated a correlation between drug accumulation and selective cytotoxicity. Inhibitors of coralyne uptake included several protoberberine-related compounds. Of these, palmatine, a minimally cytotoxic protoberberine, both inhibited coralyne accumulation and reduced cytotoxicity against SF-268 cells, but not against RPMI 8402 cells. Despite the structural resemblance of protoberberines to catecholamines, our experiments using inhibitors and cells expressing biogenic amine uptake systems have ruled out the involvement of biogenic amine uptake1, uptake2, and vesicular monoamine transport systems. Uptake systems remaining as candidates, supported by preliminary data, include transport via vesicles derived from specialized membrane invaginations and selected carrier-mediated organic amine transport systems.

A role for the amino terminus of human topoisomerase I.

These studies indicate that SV40T antigen binds the amino terminus of human top1 both in vitro and in vivo. Additional in vitro data suggest that the interaction between these two proteins does not require DNA as an intermediary. Taken together with the finding that the amino terminus of top 1 binds the putative helicase nucleolin, these results implicate helicase binding as a general function of the amino terminus of human top1. Binding of top1 by helicases may be important in the management of structural alterations in DNA produced by helicases. The potential importance of helicase-topoisomerase interactions has been highlighted by recent data indicating that the protein defective in Bloom's syndrome is a helicase with a yeast homologue that is known to bind topoisomerases.