Phase 1/2 study of ocaratuzumab, an Fc-engineered humanized anti-CD20 monoclonal antibody, in low-affinity FcγRIIIa patients with previously treated follicular lymphoma

This phase 2 study assessed the safety and efficacy of ocaratuzumab, a humanized anti-CD20 monoclonal antibody. Fifty patients with previously treated follicular lymphoma (FL) and a low-affinity genotype of FcγRIIIa received ocaratuzumab 375 mg/m(2) weekly for 4 weeks. Grade 3/4/5 adverse events (AEs) were reported in 11/1/1 patients, respectively. Serious AEs were reported by 11/50 patients, and three discontinued due to AEs. One patient died from aspiration pneumonia due to possibly drug-related nausea and vomiting. Investigator-assessed response rate was 30% (15/50), including four complete responses (CR), three CR unconfirmed (CRu) and eight partial responses (PR). Investigator-assessed median Progression-free survivial (PFS) was 38.3 weeks. Ocaratuzumab's pharmacokinetic profile was similar to that reported for rituximab. Lymphocyte subset analysis showed significant, selective reduction of B-cells during and after ocaratuzumab treatment. Ocaratuzumab at this dose and schedule is active and well tolerated in patients with previously treated FL with low affinity FcγRIIIa genotypes. ClinTrials registry number: NCT00354926.

Results of a phase 1 study of AME-133v (LY2469298), an Fc-engineered humanized monoclonal anti-CD20 antibody, in FcγRIIIa-genotyped patients with previously treated follicular lymphoma

PURPOSE

AME-133v is a humanized monoclonal antibody engineered to have increased affinity to CD20 and mediate antibody-dependent cell-mediated cytotoxicity (ADCC) better than rituximab. Safety, pharmacokinetics, and efficacy were assessed in a phase 1/2 trial in patients with previously treated follicular lymphoma (FL).

PATIENTS AND METHODS

AME-133v was characterized in vitro by ADCC and cell binding assays. A phase 1 study was conducted in which 23 previously treated patients with FL were assigned sequentially to one of five dose-escalation cohorts of AME-133v at 2, 7.5, 30, 100, or 375 mg/m(2) weekly × 4 doses.

RESULTS

AME-133v showed a 13- to 20-fold greater binding affinity for CD20 and was 5- to 7-fold more potent than rituximab in ADCC assays. Cell binding assays showed AME-133v and rituximab competed for an overlapping epitope on the CD20 antigen, and AME-133v inhibited binding of biotinylated rituximab to CD20 in a concentration-dependent manner. AME-133v was well tolerated by patients and common related adverse events included chills and fatigue. One patient experienced a dose-limiting toxicity of neutropenia. AME-133v showed nonlinear pharmocokinetics with properties similar to rituximab. Selective reduction of B cells during and after AME-133v treatment was shown by flow cytometry of peripheral blood. A partial or complete response was observed in 5 of 23 (22%) patients and the median progression-free survival was 25.4 weeks.

CONCLUSIONS

AME-133v was safe and well tolerated at the doses tested. AME-133v showed encouraging results as an anti-CD20 therapy in heavily pretreated FL patients with the less favorable FcγRIIIa F-carrier genotype.

131I-chTNT-1/B mAb: tumour necrosis therapy for malignant astrocytic glioma

Treatment of malignant glioma is therapeutically challenging. Despite improvements in neurosurgery, radiotherapy and chemotherapy, few patients diagnosed with anaplastic astrocytoma (AA) or glioblastoma multiforme (GBM) (WHO grades 3 and 4, respectively) will live beyond 2 years. Poor survival is due to the highly invasive nature and protected location of these tumours. Most malignant gliomas cannot be completely resected or irradiated due to their ability to infiltrate diffusely into normal brain tissue. Brain tissue is protected from the systemic circulation via the blood-brain barrier (BBB), which impedes entry of water-soluble chemotherapeutic agents into the tumour at therapeutic concentrations. (131)I-chTNT-1/B mAb (Cotara) employs an innovative strategy to treat the invasive portion of the tumour and the core lesion. (131)I-chTNT-1/B mAb is a genetically engineered, radiolabelled, chimeric monoclonal antibody specific for a universal intracellular antigen (i.e., DNA/histone H1 complex) exposed in the necrotic core of malignant gliomas. This antigen provides an abundant, insoluble, non-diffusible anchor for the mAb. Once localised to necrotic regions of the tumour, (131)I-chTNT-1/B mAb delivers a cytotoxic dose of (131)I radiation to the core lesion. (131)I-chTNT-1/B mAb is delivered via convection-enhanced delivery in order to maximise coverage to the tumour and the invasive front of the glial tumour. The clinical experience to date with (131)I-chTNT-1/B mAb is presented.

Safety and Feasibility of Convection-enhanced Delivery of Cotara for the Treatment of Malignant Glioma: Initial Experience in 51 Patients

OBJECTIVE:

We report the safety and feasibility of using convection-enhanced delivery to administer Cotara (Peregrine Pharmaceuticals, Inc., Tustin, CA), a novel radioimmunotherapeutic agent, to patients with malignant glioma.

METHODS:

Between April 1998 and November 2002, 51 patients with histologically confirmed malignant glioma received Cotara by convection-enhanced delivery. Most patients (88%) were treated with Cotara targeting tumor volume-dependent, single or multiple administrations of activity ranging from 0.5 to 3.0 mCi/cm3 of baseline clinical target volume. Two weeks after infusion, single-photon emission computed tomographic imaging determined the spatial distribution of Cotara. Patients were followed for as long as 41 months (average follow-up, 5 mo). Safety was evaluated on the basis of incidence of procedure-related, neurological, and systemic adverse events. Feasibility was evaluated in a subset of patients on the basis of the correlation between the prescribed activity and the actual activity administered to the targeted region.

RESULTS:

Fifty-one patients, 37 with recurrent glioblastoma multiforme, 8 with newly diagnosed glioblastoma multiforme, and 6 with recurrent anaplastic astrocytomas, were treated. Average tumor volume was 36 ± 27.6 cm3 (range, 5–168 cm3). Of the 67 infusions, 13 (19%), 52 (78%), and 2 (3%) delivered less than 90%, 100 ± 10%, and more than 110%, respectively, of the prescribed administered activity to the targeted region. Treatment-emergent, drug-related central nervous system adverse events included brain edema (16%), hemiparesis (14%), and headache (14%). Systemic adverse events were mild. Several patients had objective responses to Cotara.

CONCLUSION:

The majority of Cotara infusions delivered between 90 and 110% of the prescribed administered activity to the targeted region. This method of administration has an acceptable safety profile compared with literature reports of other therapeutics delivered by convection-enhanced delivery.

24-Hour IOP control with once-daily bimatoprost, timolol gel-forming solution, or latanoprost: a 1-month, randomized, comparative clinical trial

PURPOSE

To compare the efficacy and safety of once-daily (QD) bimatoprost, latanoprost, and timolol gel-forming solution in providing 24-hour intraocular pressure (IOP) control.

DESIGN

This was a randomized, multicenter, investigator-masked, prospective, parallel-group, clinical trial.

PARTICIPANTS

Patients with open-angle glaucoma or ocular hypertension.

INTERVENTION

After washout of any previous ocular hypotensive medications, patients were randomly assigned to treatment with bimatoprost 0.03% ophthalmic solution QD (n=38) or latanoprost 0.005% ophthalmic solution QD (n=38) between 7 and 9 pm, or timolol maleate 0.5% gel-forming ophthalmic solution QD (n=39) between 7 and 9 am for 1 month.

MAIN OUTCOME MEASURES

The primary outcome measure, circadian IOP, was measured at eight time points over the course of 24 hours beginning at 8 am on day 28 and with the last measurement at 8 am on day 29. IOP was also measured at 8 am and 10 am at baseline and at 8 am on day 14. Safety measures included adverse events, biomicroscopy, visual acuity, heart rate, and blood pressure.

RESULTS

At 10 am (peak drug effect) on day 28, the mean IOP reduction from baseline was significantly greater with bimatoprost (9.3 mm Hg, 40.3%) than with timolol gel (7.1 mm Hg, 31.1%; P=.024, Wilcoxon rank sum test) or latanoprost (7.4 mm Hg, 33.3%). In the overall analysis of IOP measured over the course of 24 hours, mean IOP was significantly lower with bimatoprost or latanoprost than with timolol gel (P<.001; analysis of repeated measures). The analysis of repeated measures also showed a significant difference between bimatoprost and latanoprost (P=.003). In the area-under-the-curve analysis, bimatoprost and latanoprost were superior to timolol gel (P< or =.018) but comparable to each other (P> or =.223). All treatment regimens were well tolerated, with few discontinuations due to adverse events. There were no significant effects on systemic safety parameters.

CONCLUSION

Once-daily bimatoprost or latanoprost provided significantly better 24-hour IOP control than timolol gel in patients with glaucoma or ocular hypertension. Some measurements suggested a trend for greater efficacy of bimatoprost over latanoprost. All three treatments were well tolerated.

Effects of AGN 192024, a new ocular hypotensive agent, on aqueous dynamics

PURPOSE

To determine the mechanism of intraocular pressure lowering for the Ocular Hypotensive Lipid, AGN 192024 (Allergan, Inc, Irvine, California).

METHODS

Twenty-five normal human volunteers between the ages of 21 and 48 took part in a randomized, double-masked, placebo-controlled, paired-comparison study in which intraocular pressure, aqueous humor flow, and tonographic resistance to outflow were studied. Measurements of aqueous flow were made during the day and at night while subjects slept. Intraocular pressure was measured with the Goldmann tonometer, and resistance to outflow was measured by electronic recording Schiötz tonography.

RESULTS

Intraocular pressure was decreased by 20% on day 3 in AGN 192024-treated eyes in comparison with placebo-treated eyes in normal subjects (P <.001). Aqueous humor flow was stimulated 13% during the day (P =.007) and 14% at night (P =.014) by the drug. Tonographic resistance to outflow was decreased 26% by AGN 192024 (P <.001), and apparent resistance to outflow (the ratio of intraocular pressure to aqueous flow) was decreased 31% (P <.001). Assuming that AGN 192024 does not cause prolonged lowering of episcleral venous pressure, the results show that pressure-insensitive outflow is enhanced by 50%, whereas tonographic facility of outflow (reciprocal of resistance) was enhanced 35%.

CONCLUSIONS

AGN 192024 is an ocular hypotensive agent that works by enhancing both pressure-sensitive and pressure-insensitive aqueous humor outflow without diminishing aqueous humor formation.

CYP2E1 expression in human lymphocytes from various ethnic populations

BACKGROUND

Monitoring CYP2E1 levels in alcoholic individuals holds inherent appeal because such determinations might indicate individuals at increased risk for alcoholic liver disease. We previously demonstrated that lymphocyte CYP2E1 expression reflects in vivo activity of the hepatic enzyme.

METHODS

To further validate this approach, the current investigation compared lymphocyte CYP2E1 content and chlorzoxazone pharmacokinetics in 51 alcoholic and nonalcoholic White, Navajo, and Mexican American subjects. After an oral dose of chlorzoxazone, blood samples were collected and lymphocytes isolated.

RESULTS

Alcoholics exhibited a 2-fold elevation in lymphocyte CYP2E1 messenger ribonucleic acid (mRNA) and protein compared to nonalcoholics. Chlorzoxazone clearance rates were 1.9-fold higher and area under the concentration curve (AUC) values 1.8-fold lower in alcoholic individuals compared to nonalcoholics. Furthermore, chlorzoxazone clearance rates correlated (r = 0.55, p < 0.01, n = 38) with lymphocyte CYP2E1 mRNA content, and transcript levels further correlated (r = 0.52, p < 0.001, n = 38) with CYP2E1 protein content. To compare phenotype with genotype, restriction fragment length polymorphism analyses on deoxyribonucleic acid samples were performed to identify polymorphisms in the CYP2E1 gene. No subjects were homozygous for rare alleles c2 or C. Nonetheless, 27% of the Navajos and 15% of the Mexican Americans were heterozygous for the c2 allele. Two White subjects appeared heterozygous (c1/c2) when RsaI was used to characterize CYP2E1 genotype but homozygous (c1/c1) at the PstI locus. Fifteen percent of Mexican American subjects, 20% of Navajo subjects, and 6% of White subjects were heterozygous for the C allele. Neither CD nor cl/c2 genotypes were associated with alcoholism.

CONCLUSIONS

Human lymphocyte CYP2E1 mRNA levels may be useful predictors of alcohol-mediated alterations in hepatic CYP2E1 activity. Moreover, ethnicity does not appear to play a major role in the levels of expression of lymphocyte CYP2E1.

Human lymphocyte cytochrome P450 2E1, a putative marker for alcohol-mediated changes in hepatic chlorzoxazone activity

Cytochrome P450 (CYP) 2E1 is implicated in a variety of chemically initiated hepatotoxicities, including alcoholic liver disease. These pathological conditions arise from increased production of reactive intermediates caused by elevated enzyme concentrations. Thus, the ability to detect enhanced CYP2E1 levels would aid in identifying individuals at high risk for xenobiotic-promoted liver injury. With this in mind, the present investigation assessed in vivo chlorzoxazone metabolism and compared pharmacokinetic parameters with CYP2E1 expression in blood. Twenty-two subjects were recruited and divided into two groups, control subjects and alcohol abusers, based on responses to two screening questionnaires. Those individuals with higher survey scores, i.e. those who consumed alcohol more frequently, exhibited higher rates of chlorzoxazone metabolism. Indeed, a correlation (r = 0.66, p < 0.01) was obtained when scores were compared with the pharmacokinetic parameter AUC for chlorzoxazone. Lymphocyte microsomes isolated from blood samples obtained from these same individuals were subjected to immunoblot analyses to detect CYP2E1 levels. That lymphocytes contained CYP2E1 was confirmed by reverse transcription-polymerase chain reaction and sequence analysis of the cDNA. Quantification of immunoreactive bands revealed that levels of this P450 were 2.3-fold higher in alcoholics than in control subjects. This increase in lymphocyte CYP2E1 content in alcoholic subjects coincided with a 2.1-fold increase in chlorzoxazone clearance and a 2-fold decrease in the AUC for chlorzoxazone. Importantly, a correlation (r = 0.62, p < 0.01) was observed between CYP2E1 content in lymphocytes and chlorzoxazone clearance rates. Thus, monitoring lymphocyte CYP2E1 expression may provide a substitute for estimating hepatic activity of this P450.

Human hepatocytes express an array of proinflammatory cytokines after agonist stimulation or bacterial invasion

Inflammatory cells infiltrate the liver in response to microbial infection or hepatic injury. To assess the potential role hepatocytes may play in initiating or amplifying the acute inflammatory response in the liver, we used three human hepatocyte cell lines and primary human hepatocyte cultures to characterize the repertoire of cytokines that can be expressed and regulated in hepatocytes in response to agonist stimulation or bacterial infection. As reported herein, a proinflammatory cytokine gene program that includes C-X-C and C-C chemokines [interleukin-8(IL-8), growth related (GRO)-alpha, GRO-beta, GRO-gamma, epithelial neutrophil activating peptide-78 (ENA-78), and RANTES] and the cytokines tumor necrosis factor-alpha (TNF-alpha) and macrophage colony stimulating factor was upregulated in human hepatocytes after stimulation with IL-1 alpha or TNF-alpha or bacterial invasion. In contrast, expression of hematopoietic/ lymphoid growth factors by the same cells was either down-regulated (erythropoietin and stem cell factor) or unchanged (IL-7 and IL-15) in response to the identical stimuli. Hepatocytes did not express cytokines that often are associated with the regulation of antigen-specific immune responses (IL-2, IL-4, IL-5, IL-10, IL-12p40, IL-13, and interferon-gamma) or genes for several other proinflammatory cytokines [IL-1 alpha, IL-6, monocyte chemotactic protein-1 (MCP-1), and MCP-3] or hematopoietic growth factors (granulocyte colony stimulating factor, granulocyte macrophage colony stimulating factor, IL-3, and IL-11). Together, these studies suggest that hepatocytes can both initiate and amplify acute inflammatory responses in the liver through the regulated expression and secretion of a specific array of proinflammatory cytokines.

Ethanol-mediated transplacental induction of CYP2E1 in fetal rat liver

We examined the potential for the widely consumed xenobiotic ethanol to transplacentally induce fetal rat CYP2E1. Throughout gestation, rat dams were fed a liquid diet containing 5% ethanol or two separate control diets. At 2 days before term, the dams were killed, and maternal and embryonic tissues were collected. Immunoblot analysis of microsomes from fetal liver, placenta and maternal brain revealed a band that comigrated with adult liver CYP2E1. The identity of the immunoreactive protein in placenta, brain and fetal liver was substantiated as CYP2E1 through restriction enzyme digestion of a reverse transcription-polymerase chain reaction product. Quantification of immunoblots containing microsomes from maternal and fetal liver of ethanol-treated dams displayed a 1.4- and 2.4-fold increase in CYP2E1, respectively, compared with microsomes from pair-fed controls. Chlorzoxazone and low substrate concentrations of N-nitrosodimethylamine were used as metabolic probes for CYP2E1. The rate of chlorzoxazone metabolism by maternal hepatic microsomes from dams fed the 5% ethanol diet was 2.6-fold greater than that of controls. Conversely, a negligible increase was observed in the rate of metabolism by hepatic microsomes from ethanol-exposed fetuses compared with pair-fed animals. When N-nitrosodimethylamine demethylation was examined, these same fetal samples exhibited greater rates of activity (1.5-fold) compared with microsomes from control animals. However, this increase was not as great as expected considering the 2.4-fold increase in CYP2E1 protein. Collectively, fetuses exposed to a 5% ethanol diet throughout gestation exhibited transplacental induction of an hepatic CYP2E1 that may possess different catalytic properties from the analogous adult enzyme.

Expression, induction, and catalytic activity of the ethanol-inducible cytochrome P450 (CYP2E1) in human fetal liver and hepatocytes

The mechanisms responsible for ethanol-mediated teratogenesis have not been resolved. However, possible etiologies include the local formation of the teratogen acetaldehyde or oxygen radicals by fetal ethanol-oxidizing enzymes. As alcohol dehydrogenases are expressed at very low concentrations in human embryonic tissues, the ethanol-inducible P450 enzyme, CYP2E1, could be the sole catalyst of fetal ethanol oxidation. With this in mind, we examined the expression of this P450 in liver samples from fetuses ranging in gestational age from 16 to 24 weeks. Immunoblot analysis of fetal liver microsomes revealed the presence of a protein immunoreactive with CYP2E1 antibodies that exhibited a slightly lower molecular weight than that found in adult liver samples. Embryonic CYP2E1 expression was further confirmed by the reverse transcriptase reaction with RNA from a 19-week gestational fetal liver used as template. Catalytic capabilities of human fetal microsomes were assessed by measurement of the rate of ethanol oxidation to acetaldehyde, which were 12-27% of those exhibited by adult liver microsomes. Immunoinhibition studies with CYP2E1 antibodies revealed that the corresponding antigen was the major catalyst of this reaction in both fetal and adult tissues. We then assessed whether embryonic CYP2E1 was, like the adult enzyme, inducible by xenobiotics. Treatment of primary fetal hepatocyte cultures with either ethanol or clofibrate demonstrated a 2-fold increase in CYP2E1 levels compared with untreated cells. Collectively, our results indicate that CYP2E1 is present in human fetal liver, that the enzyme is functionally similar to CYP2E1 from adults, and that fetal hepatocyte CYP2E1 is inducible in culture by xenobiotics, including ethanol. Because fetal CYP2E1 mediates ethanol metabolism, the enzyme may play a pivotal role in the local production of acetaldehyde and free radicals, both of which have potential deleterious effects on the developing fetus.

Use of lymphocytes for assessing ethanol-mediated alterations in the expression of hepatic cytochrome P4502E1

The ethanol-inducible cytochrome P4502E1 (2E1) is involved in the bioactivation of numerous hepatotoxins and hepatocarcinogens. Because high levels of expression may enhance the degree and severity of hepatotoxicity from exposure to chemicals metabolized by this enzyme, a relatively noninvasive method to phenotypically distinguish those individuals exhibiting elevated concentrations of 2E1 may be useful. With this in mind, we examined whether ethanol exposure could alter 2E1 in rabbit white blood cells and liver in a similar manner. Microsomes prepared from freshly isolated, rather than cultured cells, were used to immunochemically detect 2E1. The enzyme was found in lymphocytes and neutrophils. Lymphocytes, which comprise the majority of the white cell population in rabbits, were monitored for changes in 2E1 protein levels after ethanol exposure and compared with alterations of the hepatic enzyme. Results presented herein demonstrate that the degree of enhancement in 2E1 expression of lymphocytes and liver was dependent on the length and dose of alcohol exposure. Indeed, correlations were observed between blood alcohol concentrations and 2E1 content in lymphocytes (r = 0.65, p < 0.01) and liver (r = 0.60, p < 0.01). The greatest increase in 2E1 (6- to 10-fold) occurred in both liver and lymphocytes at a dose of 15% ethanol for 12 days of treatment. This induction was evident regardless of whether blood was taken from treated and compared with untreated rabbits or if white cells were obtained from the same animal before and after ethanol exposure. The latter findings demonstrate that changes in lymphocyte 2E1 were caused by ethanol exposure and not to variability in enzyme expression among rabbits. Interestingly, at the 10% dose, elevation of 2E1 was noted as early as 3 days, declined at 6 days, and at 12 and 24 days returned to slightly higher levels than those seen at the 3-day exposure period. This pattern of 2E1 elevation was observed in both the liver and lymphocytes. In fact, at all exposure periods and at the two doses of alcohol examined, a correlation (r = 0.70, p < 0.01) was observed between lymphocyte and liver 2E1 content. Collectively, these studies show that induction of 2E1 in lymphocytes and liver occurs in a parallel fashion. Furthermore, results suggest that blood 2E1 may be used in humans as a phenotypic marker for xenobiotic-promoted alterations in the expression of the liver enzyme. These findings should have a significant impact on in vivo monitoring of this P450 enzyme.

Prediction of traffic noise: a screening technique

Traffic noise is ubiquitous in many communities and is an important environmental concern, especially for persons located near major roadways. Several different methods are available to estimate noise levels resulting from roadway traffic. These include computational, graphical, and computer modeling techniques. The prediction methodology presented here is a simplified technique that can be used for estimating noise resulting from traffic and for screening traffic noise impacts. This Traffic Noise Screening (TNS) approach consists of a series of traffic noise level prediction graphs developed for different roadway configurations. The graphs are based on the results from using the Federal Highway Administration (FHWA) STAMINA2.0 computerized noise prediction model for various scenarios. Data inputs to the TNS approach include roadway genometries, traffic volumes, vehicle travel speed, and centerline distance to the receptors. The TNS graphs allow easy estimation of traffic noise levels for use in predicting traffic-related noise impacts. This TNS approach is not intended as a substitute for detailed modeling, such as with STAMINA2.0, but as a screening tool to aid in determining when detailed modeling may be necessary. If screening results indicate that noise estimates are significant, or if the scenario is rather complex, then additional, more detailed modeling can be performed.

Development of a young man with Prader-Willi syndrome and secondary functional encopresis

A case review of a twenty-two year old man suffering from Prader-Willi Syndrome, Secondary Functional Encopresis, mental retardation and aggressive behaviour is presented. Emphasis is made in assessing this man from various developmental perspectives. This includes: personality development, cognitive development, physical abilities, sexual development and family life stage. The role of a psychiatrist in treating this complex problem is established. An eclectic approach to treatment is reviewed using many therapeutic modalities found effective with the mentally handicapped. These modalities include: group therapy, play therapy, individual psychotherapy, behavioural therapy, family therapy, and use of medication. A literature review of Prader-Willi Syndrome is included.

Emotional care of the mentally handicapped

Emotional care of the mentally handicapped is complex. The author of this paper addresses issues of development of handicapped persons, and how these persons differ from those of average intelligence. She considers the unique circumstances of the family of the handicapped person and reviews factors relevant to the assessment of an emotional problem in a person so handicapped. She also outlines treatment modalities found effective for handling emotional concerns in this population. The family physician is encouraged to use an eclectic approach. A creative and accepting attitude towards the mental handicap can be the physician's greatest asset in assisting with emotional care of this group of people.