Antileukemia activity of the novel peptidic CXCR4 antagonist LY2510924 as monotherapy and in combination with chemotherapy.

Targeting the stromal cell-derived factor 1α (SDF-1α)/C-X-C chemokine receptor type 4 (CXCR4) axis has been shown to be a promising therapeutic approach to overcome chemoresistance in acute myeloid leukemia (AML). We investigated the antileukemia efficacy of a novel peptidic CXCR4 antagonist, LY2510924, in preclinical models of AML. LY2510924 rapidly and durably blocked surface CXCR4 and inhibited stromal cell-derived factor 1 (SDF-1)α-induced chemotaxis and prosurvival signals of AML cells at nanomolar concentrations more effectively than the small-molecule CXCR4 antagonist AMD3100. In vitro, LY2510924 chiefly inhibited the proliferation of AML cells with little induction of cell death and reduced protection against chemotherapy by stromal cells. In mice with established AML, LY2510924 caused initial mobilization of leukemic cells into the circulation followed by reduction in total tumor burden. LY2510924 had antileukemia effects as monotherapy as well as in combination with chemotherapy. Gene expression profiling of AML cells isolated from LY2510924-treated mice demonstrated changes consistent with loss of SDF-1α/CXCR4 signaling and suggested reduced proliferation and induction of differentiation, which was proved by showing the attenuation of multiple prosurvival pathways such as PI3K/AKT, MAPK, and ß-catenin and myeloid differentiation in vivo. Effective disruption of the SDF-1α/CXCR4 axis by LY2510924 may translate into effective antileukemia therapy in future clinical applications.

Phase I study of enzastaurin and bevacizumab in patients with advanced cancer: safety, efficacy and pharmacokinetics.

PURPOSE: Given distinct mechanism of actions of enzastaurin and bevacizumab, preclinical studies suggest enhanced antitumor activity in combination. This phase I study assessed the combination's safety and efficacy. PATIENTS AND METHODS: Six advanced cancer patients could be enrolled in each of 11 cohorts. Patients received an enzastaurin loading dose. Oral enzastaurin (500 mg once daily [QD], 250 mg twice daily [BID], 375 mg BID, 500 mg BID, and 750 mg BID) was escalated in each cohort in combination with bevacizumab dosed at 5 mg/kg every 2 weeks, 10 mg/kg every 2 weeks, or 15 mg/kg every 3 weeks until a dose-limiting toxicity (DLT) occurred in 2 of 6 patients in any cohort. RESULTS: Sixty-seven patients (31, ovarian cancer [ovcar]) were evaluable for safety and efficacy. Six treatment-related DLTs occurred: grade 3 fatigue (n=4), grade 4 cerebral hemorrhage, and grade 3 elevated aspartate transaminase. Common drug-related toxicities included change in color of urine and stool, fatigue, pain, diarrhea, and nausea. The maximum tolerated dose of enzastaurin was 750 mg BID in combination with any tested bevacizumab dose/schedule. Overall response rate was 19.4 % (32.3 % ovcar). Median time to progression was 3.7 months (95 % confidence interval [CI], 2.7-5.5), with 8.3 months (95 % CI, 3.7-11.1) in ovcar. Overall, 35.9 % (50.4 % ovcar) of patients remained without disease progression after 6 months. CONCLUSION: The recommended phase II doses of enzastaurin were 500 mg QD up to 500 mg BID with any tested dose/schedule of bevacizumab. This combination demonstrated encouraging clinical activity, particularly in ovcar.

A phase I trial of enzastaurin in patients with recurrent gliomas.

PURPOSE: Enzastaurin is a selective inhibitor of protein kinase C beta. Prior phase I studies did not show increased drug exposures with escalating once daily administration. Limits from gastrointestinal absorption may be overcome by twice daily dosing, potentially improving antitumor effects. EXPERIMENTAL DESIGN: We conducted a phase I dose escalation study in 26 patients with recurrent malignant glioma, stratified by use of enzyme-inducing antiepileptic drugs, to investigate whether divided twice daily dosing results in higher exposures compared with once daily dosing. Phosphorylated glycogen synthase 3 beta was analyzed as a potential biomarker of enzastaurin activity. RESULTS: Enzastaurin was poorly tolerated at all dose levels evaluated (500, 800, and 1,000 mg total daily), with thrombocytopenia and prolonged QTc as dose-limiting toxicities. The average drug concentration of enzastaurin under steady-state conditions was doubled by twice daily dosing compared with daily dosing [1.990; 90% confidence interval (CI), 1.450-2.730]. Additionally, geometric mean ratios doubled with 800 versus 500 mg dosing for both daily (2.687; 90% CI, 1.232-5.860) and twice daily regimens (1.852; 90% CI, 0.799-4.292). Two patients achieved long-term benefit (over 150 weeks progression free). CONCLUSIONS: Higher and more frequent dosing of enzastaurin resulted in improved drug exposure but with unacceptable toxicity at the doses tested. Phosphorylated glycogen synthase 3 beta may be a useful biomarker of the biological activity of enzastaurin. Enzastaurin has activity in a subset of malignant glioma patients and warrants continued study in combination with other agents using a maximal once daily dose of 500 mg.

Development and validation of a drug activity biomarker that shows target inhibition in cancer patients receiving enzastaurin, a novel protein kinase C-beta inhibitor.

PURPOSE: To evaluate the effects of the novel protein kinase C (PKC) inhibitor enzastaurin on intracellular phosphoprotein signaling using flow cytometry and to use this approach to measure enzastaurin effects on surrogate target cells taken from cancer patients that were orally dosed with this agent. EXPERIMENTAL DESIGN: The activity of PKC was assayed in intact cells using a modification of published techniques. The U937 cell line and peripheral blood mononuclear cells were stimulated with phorbol ester, fixed, permeabilized, and reacted with an antibody specific for the phosphorylated forms of PKC substrates. The processed samples were quantitatively analyzed using flow cytometry. The assay was validated for selectivity, sensitivity, and reproducibility. Finally, blood was obtained from volunteer cancer patients before and after receiving once daily oral doses of enzastaurin. These samples were stimulated ex vivo with phorbol ester and were assayed for PKC activity using this approach. RESULTS: Assay of U937 cells confirmed the selectivity of the antibody reagent and enzastaurin for PKC. Multiparametric analysis of peripheral blood mononuclear cells showed monocytes to be the preferred surrogate target cell. Day-to-day PKC activity in normal donors was reproducible. Initial results showed that five of six cancer patients had decreased PKC activity following enzastaurin administration. In a following study, a group of nine patients displayed a significant decrease in PKC activity after receiving once daily oral doses of enzastaurin. CONCLUSION: An inhibition of surrogate target cell PKC activity was observed both in vitro and ex vivo after exposure to the novel kinase inhibitor, enzastaurin.

The protein kinase Cbeta-selective inhibitor, Enzastaurin (LY317615.HCl), suppresses signaling through the AKT pathway, induces apoptosis, and suppresses growth of human colon cancer and glioblastoma xenografts.

Activation of protein kinase Cbeta (PKCbeta) has been repeatedly implicated in tumor-induced angiogenesis. The PKCbeta-selective inhibitor, Enzastaurin (LY317615.HCl), suppresses angiogenesis and was advanced for clinical development based upon this antiangiogenic activity. Activation of PKCbeta has now also been implicated in tumor cell proliferation, apoptosis, and tumor invasiveness. Herein, we show that Enzastaurin has a direct effect on human tumor cells, inducing apoptosis and suppressing the proliferation of cultured tumor cells. Enzastaurin treatment also suppresses the phosphorylation of GSK3betaser9, ribosomal protein S6(S240/244), and AKT(Thr308). Oral dosing with Enzastaurin to yield plasma concentrations similar to those achieved in clinical trials significantly suppresses the growth of human glioblastoma and colon carcinoma xenografts. As in cultured tumor cells, Enzastaurin treatment suppresses the phosphorylation of GSK3beta in these xenograft tumor tissues. Enzastaurin treatment also suppresses GSK3beta phosphorylation to a similar extent in peripheral blood mononuclear cells (PBMCs) from these treated mice. These data show that Enzastaurin has a direct antitumor effect and that Enzastaurin treatment suppresses GSK3beta phosphorylation in both tumor tissue and in PBMCs, suggesting that GSK3beta phosphorylation may serve as a reliable pharmacodynamic marker for Enzastaurin activity. With previously published reports, these data support the notion that Enzastaurin suppresses tumor growth through multiple mechanisms: direct suppression of tumor cell proliferation and the induction of tumor cell death coupled to the indirect effect of suppressing tumor-induced angiogenesis.

A Phase 1 Study of LY2874455, an Oral Selective pan-FGFR Inhibitor, in Patients with Advanced Cancer.

BACKGROUND: We report here a phase 1 study of LY2874455, a potent oral selective pan-fibroblast growth factor receptor (FGFR) inhibitor. OBJECTIVE: The primary objective was to determine the recommended phase 2 dosing (RP2D). Secondary objectives included determining toxicity, antitumor activity, pharmacokinetics (PK), and pharmacodynamic (PD) properties of LY2874455. PATIENTS AND METHODS: This study comprised two parts: (a) dose escalation with 3 + 3 cohorts in patients with solid tumors and (b) dose-expansion cohorts in patients with gastric cancer (GC) and non-small cell lung cancer (NSCLC). Part A: 36 patients in 11 dose cohorts ranging from 2 to 24 mg twice daily (BID). RP2D was 16 mg BID. Part B: GC cohort, 29 patients, NSCLC cohort, 27 patients, all treated at the RP2D. RESULTS: LY2874455 was slowly absorbed and generally showed linear PK. The effective half-life was ∼12 h. PD properties of LY2874455 occurred at doses ≥10 mg by increases in serum phosphorus. Phosphate binders were administered to control serum phosphorus. LY2874455 was generally well tolerated; most toxicities were grade 1 or 2; most frequent were hyperphosphatemia, diarrhea, and stomatitis. EFFICACY: part A: 24 patients evaluable: 1 patient in the 14-mg BID cohort with GC had a partial response (PR); 14 patients had stable disease (SD); part B: NSCLC cohort: 11 of 12 evaluable patients had SD; GC cohort: 15 patients evaluable: 1 patient with PR; 12 patients with SD. CONCLUSIONS: LY2874455 has an RP2D of 16 mg BID and demonstrated good tolerability and activity in solid-organ cancer patients. The role of FGFR inhibition on tumor growth in patients requires further study. (NCT01212107).

Phase I trial of the cryptophycin analogue LY355703 administered as an intravenous infusion on a day 1 and 8 schedule every 21 days.

The cryptophycin analogue LY355703 is a potent inhibitor of microtubule polymerization that displays in vitro and in vivo activity in cell lines and tumor xenografts displaying the multidrug-resistant phenotype. In a Phase I trial, 25 patients received LY355703 as a 2-h i.v. infusion on day 1 and day 8 repeated every 3 weeks. Doses were escalated from 0.1 to 2.22 mg/m2 using a modified continual reassessment method. Neurological toxicity was found to be dose-limiting at 1.84 and 2.22 mg/m2. Among four patients treated at these doses, two had grade 4 constipation/ileus, one with severe myalgias, and one had grade 3 motor neuropathy. These findings were reversible. The 1.5 mg/m2 dose level was well tolerated. An amended twice-weekly schedule was pursued in 11 patients in an attempt to improve dose intensity and avoid dose-limiting neurotoxicity. Doses of >0.75 mg/m2 on a day 1, 4, 8, and 11 schedule every 21 days were not tolerated as a result of nausea/constipation, suggesting that LY335703 toxicity is not schedule dependent and is related to cumulative dose. LY355703 plasma concentrations measured by liquid chromatography with tandem mass spectrometry were evaluated using a population pharmacokinetic model. LY355703 was eliminated rapidly with a short terminal half-life that ranged from 0.8 to 3.9 h. Interpatient variability with respect to plasma clearance and volume of distribution, including covariates, was moderate at 32% and 39%, respectively. Maximum plasma concentration and area under the plasma concentration-time curve were linear over the dose range studied. A patient with non-small cell lung cancer previously treated with taxanes experienced a partial response lasting 4 months, and five patients had stable disease lasting > or =3 months. LY355703 at a dose of 1.5 mg/m2 is recommended for Phase II evaluation on a days 1 and 8 schedule. Twice-weekly dosing did not allow improvement in dose intensity or tolerability.

Phase 2 study of cryptophycin 52 (LY355703) in patients previously treated with platinum based chemotherapy for advanced non-small cell lung cancer.

BACKGROUND: Cryptophycin 52 is a novel antitubulin drug with in vitro and in vivo activity in non-small cell lung cancer. Based upon promising Phase 1 data, a multicenter trial was performed to evaluate the drug in previously treated non-small cell lung cancer (NSCLC). METHODS: Patients with Stage IIIb (pleural effusion) or Stage IV NSCLC and performance status 0-1 with adequate organ function who had received at least one and no more than two prior chemotherapy regimens (one of which must have contained a platinum agent) were eligible. Cryptophycin 52 was administered at a dose of 1.5 mg/m(2) day 1 and 8 every 3 weeks. Patients were reassessed every two cycles. RESULTS: Twenty-six patients were enrolled of whom 25 are evaluable for toxicity and response. There were no responders, toxicity was predominantly neurologic in the form of peripheral neuropathy and constipation. After the first 12 patients were enrolled, the dose was lowered to 1.125 mg/m(2) day 1 and 8. Toxicity was substantially reduced with this maneuver. Median survival was 4.1 months. The median number of cycles was two, however ten patients received four or more courses of therapy. CONCLUSION: Cryptophycin 52 failed to produce measurable responses utilizing this schedule. In 40% of patients there was evidence of disease stabilization. Toxicity at 1.5 mg/m(2) was unacceptable. Since activity and toxicity may be dose and schedule dependent, other schedules of cryptophycin 52 should be considered.

A phase I trial of LY2510924, a CXCR4 peptide antagonist, in patients with advanced cancer.

PURPOSE: Overexpression of C-X-C motif receptor 4 (CXCR4) is implicated in tumor progression. LY2510924 is a peptide antagonist, which blocks stromal cell-derived factor-1 (SDF1) from CXCR4 binding. EXPERIMENTAL DESIGN: This phase I study included two parts: a 3+3 dose escalation (part A) and dose confirmation (part B). LY2510924 was administered as a daily subcutaneous injection on a 28-day cycle. The primary objective was to determine the recommended phase II dose. Secondary objectives included safety, pharmacokinetics, efficacy, and pharmacodynamic response, including mobilization of CD34(+) hematopoietic stem cells into the peripheral blood. RESULTS: Forty-five patients were enrolled, 25 in part A and 20 in part B. Patients were administered increasing doses of LY2510924: 1.0, 2.5, 5.0, 10, 20, and 30 mg/day for part A and 2.5 or 20 mg/day for part B. Two patients (30-mg/day cohort) experienced dose-limiting toxicities of grade 3 increased neutrophil count. The maximum tolerated dose (MTD) was 20 mg/day. The most common drug-related treatment-emergent adverse events were fatigue (9%), injection-site reaction (9%), injection site pruritus (7%), and nausea (7%). The best response was stable disease for nine patients (20%). At the end of cycle 1, mean peak LY2510924 plasma concentration and the 24-hour area under the plasma concentration versus time curve increased slightly more than dose proportionally. LY2510924 dose dependently increased CD34(+) cell counts in peripheral blood up to 18-fold. CONCLUSIONS: LY2510924 demonstrated CD34(+) cell mobilization at doses ≥2.5 mg/day with a tolerable safety profile up to an MTD of 20 mg/day.

Phase II and pharmacogenomics study of enzastaurin plus temozolomide during and following radiation therapy in patients with newly diagnosed glioblastoma multiforme and gliosarcoma.

This open-label, single-arm, phase II study combined enzastaurin with temozolomide plus radiation therapy (RT) to treat glioblastoma multiforme (GBM) and gliosarcoma. Adults with newly diagnosed disease and Karnofsky performance status (KPS) ≥ 60 were enrolled. Treatment was started within 5 weeks after surgical diagnosis. RT consisted of 60 Gy over 6 weeks. Temozolomide was given at 75 mg/m(2) daily during RT and then adjuvantly at 200 mg/m(2) daily for 5 days, followed by a 23-day break. Enzastaurin was given once daily during RT and in the adjuvant period at 250 mg/day. Cycles were 28 days. The primary end point was overall survival (OS). Progression-free survival (PFS), toxicity, and correlations between efficacy and molecular markers analyzed from tumor tissue samples were also evaluated. A prospectively planned analysis compared OS and PFS of the current trial with outcomes from 3 historical phase II trials that combined novel agents with temozolomide plus RT in patients with GBM or gliosarcoma. Sixty-six patients were enrolled. The treatment regimen was well tolerated. OS (median, 74 weeks) and PFS (median, 36 weeks) results from the current trial were comparable to those from a prior phase II study using erlotinib and were significantly better than those from 2 other previous studies that used thalidomide or cis-retinoic acid, all in combination with temozolomide plus RT. A positive correlation between O-6-methylguanine-DNA methyltransferase promoter methylation and OS was observed. Adjusting for age and KPS, no other biomarker was associated with survival outcome. Correlation of relevant biomarkers with OS may be useful in future trials.

A phase I/II trial of enzastaurin in patients with recurrent high-grade gliomas.

Enzastaurin, a potent inhibitor of protein kinase C-beta, inhibits angiogenesis and has direct cytotoxic activity against glioma cells in preclinical studies. Patients with recurrent high-grade gliomas were stratified by histology and use of enzyme-inducing antiepileptic drugs (EIAEDs). Patients on EIAED were treated on the phase I dose-escalation portion of the trial with evaluation of serum pharmacokinetics as the primary endpoint. Patients not on EIAED were treated on the phase II portion of the trial with radiographic response and progression-free survival (PFS) as primary objectives. Patients in phase I received enzastaurin 525-900 mg/d. Phase II patients received 500 or 525 mg/d. One hundred and eighteen patients were accrued to this trial. Therapy was well tolerated with thrombosis, thrombocytopenia, hemorrhage, and elevated alanine aminotransferase as the most commonly observed drug-associated grade 3 or higher toxicities. Patients on EIAED had serum enzastaurin exposure levels approximately 80% lower than those not on EIAED. Dose escalations up to 900 mg/d did not substantially increase serum exposure levels and a maximally tolerated dose was never reached. Twenty-one of 84 evaluable patients (25%) experienced an objective radiographic response. The 6-month PFS was 7% for patients with glioblastoma and 16% for patients with anaplastic glioma. Phosphorylation of glycogen synthase kinase-3 in peripheral blood mononuclear cells was identified as a potential biomarker of drug activity. Enzastaurin has anti-glioma activity in patients with recurrent high-grade glioma, but does not appear to have enough single-agent activity to be useful as monotherapy.

Enzastaurin plus temozolomide with radiation therapy in glioblastoma multiforme: a phase I study.

We conducted a phase I study to determine the safety and recommended phase II dose of enzastaurin (oral inhibitor of the protein kinase C-beta [PKCbeta] and the PI3K/AKT pathways) when given in combination with radiation therapy (RT) plus temozolomide to patients with newly diagnosed glioblastoma multiforme or gliosarcoma. Patients with Karnofsky performance status > or =60 and no enzyme-inducing anti-epileptic drugs received RT (60 Gy) over 6 weeks, concurrently with temozolomide (75 mg/m(2) daily) followed by adjuvant temozolomide (200 mg/m(2)) for 5 days/28-d cycle. Enzastaurin was given once daily during RT and adjuvantly with temozolomide; the starting dose of 250 mg/d was escalated to 500 mg/d if < or =1/6 patients had dose-limiting toxicity (DLT) during RT and the first adjuvant cycle. Patients continued treatment for 12 adjuvant cycles unless disease progression or unacceptable toxicity occurred. Twelve patients enrolled. There was no DLT in the first 6 patients treated with 250 mg enzastaurin. At 500 mg, 2 of 6 patients experienced a DLT (1 Grade 4 and 1 Grade 3 thrombocytopenia). The patient with Grade 3 DLT recovered to Grade <1 within 28 days and adjuvant temozolomide and enzastaurin was reinitiated with dose reductions. The other patient recovered to Grade <1 toxicity after 28 days and did not restart treatment. Enzastaurin 250 mg/d given concomitantly with RT and temozolomide and adjuvantly with temozolomide was well tolerated and is the recommended phase II dose. The proceeding phase II trial has finished accrual and results will be reported in 2009.

Phase III study of enzastaurin compared with lomustine in the treatment of recurrent intracranial glioblastoma.

PURPOSE: This phase III open-label study compared the efficacy and safety of enzastaurin versus lomustine in patients with recurrent glioblastoma (WHO grade 4). PATIENTS AND METHODS: Patients were randomly assigned 2:1 to receive 6-week cycles of enzastaurin 500 mg/d (1,125-mg loading dose, day 1) or lomustine (100 to 130 mg/m(2), day 1). Assuming a 45% improvement in progression-free survival (PFS), 397 patients were required to provide 80% power to achieve statistical significance at a one-sided level of .025. RESULTS: Enrollment was terminated at 266 patients (enzastaurin, n = 174; lomustine, n = 92) after a planned interim analysis for futility. Patient characteristics were balanced between arms. Median PFS (1.5 v 1.6 months; hazard ratio [HR] = 1.28; 95% CI, 0.97 to 1.70), overall survival (6.6 v 7.1 months; HR = 1.20; 95% CI, 0.88 to 1.65), and 6-month PFS rate (P = .13) did not differ significantly between enzastaurin and lomustine, respectively. Stable disease occurred in 38.5% and 35.9% of patients and objective response occurred in 2.9% and 4.3% of patients, respectively. Time to deterioration of physical and functional well-being and symptoms did not differ between arms (HR = 1.12; P = .54). Four patients discontinued enzastaurin because of drug-related serious adverse events (AEs). Eleven patients treated with enzastaurin died on study (four because of AEs; one was drug-related). All four deaths that occurred in patients receiving lomustine were disease-related. Grade 3 to 4 hematologic toxicities were significantly higher with lomustine (46 events) than with enzastaurin (one event; P < or = .001). CONCLUSION: Enzastaurin was well tolerated and had a better hematologic toxicity profile but did not have superior efficacy compared with lomustine in patients with recurrent glioblastoma.

In Vivo Measurements of Tumor Metabolism and Growth after Administration of Enzastaurin Using Small Animal FDG Positron Emission Tomography.

Background. The use of 2-[(18)F]fluoro-2-deoxy-D-glucose ([(18)F]FDG) may help to establish the antitumor activity of enzastaurin, a novel protein kinase C-beta II (PKC-betaII) inhibitor, in mouse xenografts. Methods. The hematologic cell line RAJI and the solid tumor cell line U87MG were each implanted in NOD/SCID mice. Standard tumor growth measurements and [(18)F]FDG PET imaging were performed weekly for up to three weeks after tumor implantation and growth. Results. Concomitant with caliper measurements, [(18)F]FDG PET imaging was performed to monitor glucose metabolism. Heterogeneity of glucose uptake in various areas of the tumors was observed after vehicle or enzastaurin treatment. This heterogeneity may limit the use of [(18)F]FDG PET imaging to measure enzastaurin-associated changes in xenograft tumors. Conclusion. [(18)F]FDG PET imaging technique does not correlate with standard caliper assessments in xenografts to assess the antitumor activity of enzastaurin. Future studies are needed to determine the use of [(18)F]FDG PET imaging in preclinical models.

A phase I safety, tolerability, and pharmacokinetic study of enzastaurin combined with capecitabine in patients with advanced solid tumors.

Enzastaurin, an oral inhibitor of protein kinase Cbeta, affects signal transduction associated with angiogenesis, proliferation, and survival. Capecitabine is converted to 5-fluoruracil by thymidine phosphorylase, a putative angiogenic factor. The all-oral combination of the two drugs offers the potential for targeting angiogenesis in capecitabine-sensitive tumors with nonoverlapping toxicities. Patients with advanced cancer initially received single-agent enzastaurin to achieve steady-state concentrations (cycle 1). In subsequent 21-day cycles, enzastaurin was given orally, once daily, on days 1-21 and capecitabine orally, twice daily (b.i.d.), on days 1-14 in three dose-level cohorts. Three dose-escalation cohorts were studied: cohort 1 (n=8), 350 mg of enzastaurin +capecitabine (750 mg/m2 b.i.d.); cohort 2 (n=7), enzastaurin (350 mg)+capecitabine (1000 mg/m2 b.i.d.); cohort 3 (n=12), 525-mg capsules or 500-mg enzastaurin+capecitabine (1000 mg/m2 b.i.d.). Further dose escalation was not pursued because of emerging data that enzastaurin systemic exposure did not increase at doses above 525 mg. Although a traditional toxicity-based maximum tolerated dose was not achieved, the highest dosing cohort represented a biologically relevant dose of enzastaurin, on the basis of preclinical data and correlative pharmacodynamic biomarker assays of protein kinase Cbeta inhibition in peripheral blood mononucleocytes, in combination with a standard dose of capecitabine. For the 500/525-mg dose, ratios of total enzastaurin analyte geometric means (i.e. enzastaurin alone versus enzastaurin with capecitabine) reflected a trend toward decreased enzastaurin exposure, but did not reach statistical significance. The pharmacokinetic parameters of capecitabine with enzastaurin were similar to those previously reported for single-agent capecitabine. The regimen was well tolerated, without any consistent pattern of drug-related grade 3 or grade 4 toxicities being observed. Although no objective tumor responses were documented, five patients maintained stable disease for >or=6 months (range: 6-9.7 months). The recommended phase II dose of this combination, based on the results of this study, is enzastaurin at a daily dose of 500 mg (tablet formulation) and capecitabine (1000 mg/m2, b.i.d.) on days 1-14 every 21 days. Further disease-directed studies are warranted, such as in malignancies in the treatment of which both capecitabine and inhibitors of angiogenesis have previously been benchmarked as being effective.

Utilization and cost of health care services associated with primary malignant brain tumors in the United States.

OBJECTIVES: To evaluate the economic burden of primary malignant brain tumors in a commercially insured population in the United States, and to identify the primary drivers of health care resource use and cost. PATIENTS AND METHODS: A retrospective cohort analysis was performed using a 1998-2000 database containing inpatient, outpatient, and pharmacy claims for employees, their dependents, and early retirees of over 50 large US employers with wide geographic distribution. Patients were followed from first brain tumor diagnosis until death, termination of health benefits coverage, or study end. Controls without any cancer diagnosis were matched at a 3:1 ratio by demographic characteristics and length of follow-up. RESULTS: Patients with malignant brain tumors (n = 653) had significantly greater health service utilization and costs for hospitalizations, emergency room visits, outpatient office visits, laboratory tests, radiology services, and pharmacy-dispensed drugs (all P < 0.05) than did controls (n = 1959). Regression-adjusted mean monthly costs were $6364 for brain tumor patients, compared with $277 for controls (P < 0.0001). The primary cost driver was inpatient care ($4502 per month). Total costs during the study period were $49,242 for those with brain tumors and $2790 for controls (P < 0.0001). CONCLUSION: Patients with malignant brain tumors accrued health care costs that were 20 times greater than demographically matched control subjects without cancer. The costs for inpatient services were the primary drivers of total health resource use. Despite their low incidence, primary malignant brain tumors produce a substantial burden on the US health care system. There is a marked need for improved and new approaches to treatment to reduce the resource use and to offset health care costs associated with this disease.

Retrospective analysis of protein kinase C-beta (PKC-beta) expression in lymphoid malignancies and its association with survival in diffuse large B-cell lymphomas.

BACKGROUND: Both mechanistic features and recent correlative findings suggest a potential role for protein kinase C-beta (PKC-beta) in tumor pathogenesis, particularly in B-cell malignancies. To evaluate the role of this gene in lymphoid malignancies, we analyzed global gene expression data to quantify PKC-beta expression across diagnostic groups and, when possible, determined correlations between PKC-beta expression and survival. RESULTS: Our analysis showed that the level of PKC-beta expression was highest in chronic lymphocytic leukemia and follicular lymphoma. Within diffuse large-B cell lymphoma (DLBCL), PKC-beta expression was significantly higher in activated B-cell- like subtype than germinal center B-cell- like subtype (P < 0.0001). Elevated PKC-beta appeared to be associated with worse survival in both of these subtypes. When analyzed within clinically defined risk groups established by the International Prognostic Index (IPI), PKC-beta expression was lowest in patients with low IPI scores (0-1). Within intermediate- and high-risk IPI groups, elevated PKC-beta expression was associated with worse survival, suggesting that PKC-beta may expand the prognostic value of the IPI. Results of global gene expression analyses of DLBCL samples corroborate previous observations that anti-apoptosis, cell proliferation, and B-cell proliferation signaling pathways are functionally related to PKC-beta. CONCLUSION: We present a first detailed pharmacogenomics report comparing PKC-beta mRNA expression across different lymphoid malignancies and evaluating it as an outcome predictor. Our findings suggest that DLBCL patients with elevated PKC-beta have a worse prognosis, indicating that further evaluation of PKC-beta as a chemotherapeutic target for lymphoid malignancies is warranted.

Phase II study of enzastaurin, a protein kinase C beta inhibitor, in patients with relapsed or refractory diffuse large B-cell lymphoma.

PURPOSE: Protein kinase C beta (PKCbeta) was identified by gene-expression profiling, preclinical evaluation, and independent immunohistochemical analysis as a rational therapeutic target in diffuse large B-cell lymphoma (DLBCL). We conducted a multicenter phase II study of a potent inhibitor of PKCbeta, enzastaurin, in patients with relapsed or refractory DLBCL. PATIENTS AND METHODS: Enzastaurin was taken orally once daily until disease progression or unacceptable toxicity occurred. Study end points included freedom from progression (FFP) for > or= two cycles (one cycle = 28 days), objective response, and toxicity. RESULTS: Fifty-five patients (median age, 68 years) were enrolled. Patients had received a median number of two prior therapies (range, one to five); six patients relapsed after high-dose therapy and autologous stem-cell transplantation. Only one grade 4 toxicity (hypomagnesemia) occurred. Grade 3 toxicities included fatigue (n = 2), edema (n = 1), headache (n = 1), motor neuropathy (n = 1), and thrombocytopenia (n = 1). No grade 3 or 4 neutropenia occurred. No deaths or discontinuations due to toxicity were reported. Fifteen patients completed less than one cycle of therapy. Twelve of 55 patients (22%; 95% CI, 13% to 46%) experienced FFP for two cycles, and eight patients remained free from progression for four cycles (15%; 95% CI, 6% to 27%). Four patients (7%; 95% CI, 2% to 18%), including three complete responders and one patient with stable disease, continue to experience FFP 20+ to 50+ months after study entry. CONCLUSION: Treatment with enzastaurin was well-tolerated and associated with prolonged FFP in a small subset of patients with relapsed or refractory DLBCL. Further studies of enzastaurin in DLBCL are warranted.

Phase I dose escalation and pharmacokinetic study of enzastaurin, an oral protein kinase C beta inhibitor, in patients with advanced cancer.

PURPOSE: This phase I study was conducted to determine the recommended dose of enzastaurin, an oral protein kinase C beta (PKCbeta) inhibitor, for phase II trials. Secondary objectives were maximum-tolerated dose (MTD), pharmacokinetics (PK), toxicity, and response. PATIENTS AND METHODS: Patients at least 18 years of age with advanced cancer and an Eastern Cooperative Oncology Group performance status of 0 or 1 lower received enzastaurin orally once daily at a starting dose of 20 mg. Dose escalation proceeded using a modified Simon design. RESULTS: All 47 patients enrolled (mean age, 58 years) received at least one dose of enzastaurin, with a median of two cycles (range, one to 17 cycles). Prevalent malignancies were lung (n = 10) and head and neck cancers (n = 9). Although no MTD was identified up to 700 mg/d, 525 mg was chosen as the recommended dose, and 12 additional patients were accrued at that level. Three dose-limiting toxicities (QTc changes) occurred: one at the 700-mg dose (patient discontinued), and two in the expansion cohort at the 525-mg dose. Total analytes (enzastaurin and its metabolites) exposure increased with increasing doses up to 240 mg, and appeared to plateau at 525 and 700 mg. Grade 1 chromaturia, fatigue, and other GI toxicities were the most common, while no clinically significant grade 3/4 toxicities occurred. Two deaths, unrelated to enzastaurin, occurred. Twenty-one patients (45%) achieved stable disease (SD) for two to 16 cycles. CONCLUSION: On the basis of plasma exposures and safety data, enzastaurin 525 mg once daily is the recommended phase II dose. Enzastaurin is well tolerated up to 700 mg/d. Evidence of early activity was seen with significant stable disease.