Drug-induced lupus associated with COL-3: report of 3 cases

BACKGROUND

Anti-angiogenesis is an exciting new approach to anticancer therapy. COL-3, a tetracycline derivative, is a novel anti-angiogenesis agent with potent preclinical anticancer activity. During the conduct of a phase 1 clinical trial for refractory metastatic cancer at the National Institutes of Health, we observed 3 individuals who developed phototoxicity followed by clinical and laboratory features of drug-induced lupus.

OBSERVATIONS

Three of 35 patients treated with COL-3 developed sunburnlike eruptions accompanied by fever and a positive antinuclear antibody titer within 8 to 29 days of starting treatment. Two of 3 had positive antihistone antibody levels and arthralgia. One patient had marked systemic manifestations including pulmonary infiltrates and elevated erythrocyte sedimentation rate remittent for more than 1 year after discontinuing COL-3 treatment. The other 2 patients' symptoms and rash abated within 2 weeks of discontinuing therapy although the serologic markers remained abnormal for the duration of follow-up.

CONCLUSIONS

COL-3 is the second tetracycline derivative to be implicated in the development of drug-induced lupus. A sunburnlike eruption immediately preceded or accompanied the systemic and serologic changes in these 3 patients. The rapid onset and the phototoxic appearance of the accompanying eruptions might suggest that damage to the keratinocytes caused the formation of neoantigens to which autoantibodies formed.

Resistance to growth inhibitory and apoptotic effects of phorbol ester and UCN-01 in aggressive cancer cell lines

7-Hydroxystaurosporine (UCN-01), a non-selective inhibitor of protein kinase C (PKC), and phorbol ester (PMA), a PKC activator, are undergoing clinical evaluations. We investigated the effects of UCN-01 and PMA on a panel of prostate cancer cell lines. While PMA induced p21WAF1/CIP1 and arrest growth of LNCaP cancer cells (IC50 = 0.5-1 nM), aggressive cancer cell lines (DU145, PC3, and PC3M) were resistant to PMA (IC50 >5000 nM). Low concentrations (25-50 nM) of UCN-01 abrogated PMA-induced p21 and growth arrest in LNCaP cells. These low doses of UCN-01 however did not inhibit proliferation of any prostate cancer cell line. PMA-sensitive LNCaP cells were resistant to clinically relevant concentrations of UCN-01 (IC50 = 1.2 microM), but UCN-01 inhibited growth of DU145 and PC3/3M with an IC50 of 200-400 nM. For comparison, PMA-sensitive HL60 leukemia cells were sensitive to UCN-01 due to rapid apoptosis caused by UCN-01. In PMA-resistant prostate cancer cells, UCN-01 downregulated cyclin D1, induced p21, caused morphological differentiation, and G1-phase arrest leading to slow cell death without caspase activation. Importantly, normal prostate epithelial cells (PrEC) were very sensitive to both PMA (IC50 = 0.2 nM) and UCN-01. In PrEC, UCN-01 downregulated cyclin D1 and arrest growth with an IC50 less than 100 nM. We conclude that loss of sensitivity to either UCN-01 or PMA accompanies progression of prostate cancer.

Phenylacetate pharmacokinetics based on iterative two-stage population analysis

STUDY OBJECTIVE

To determine the population pharmacokinetics of phenylacetate using iterative two-stage analysis implemented with ADAPT 11 software.

SETTING

United States government research hospital.

DESIGN

Retrospective pharmacokinetic analysis.

SUBJECTS

Sixty-seven patients with refractory solid tumors.

INTERVENTION

Subjects received from 1-10 courses/individual (total 141 courses) of therapy with either twice-daily administration or continuous infusions of phenylacetate.

MEASUREMENTS AND MAIN RESULTS

Extensive plasma concentration measurements were performed after the initial dose or start of infusion, with sparse sampling during subsequent courses of therapy. Phenylacetate plasma concentration-time profiles were described by a one-compartment, capacity-limited clearance model with incorporation of parameters to describe extent of induction of clearance and the rate of induction. Median estimates for volume of distribution, maximum rate of drug elimination, Michaelis-Menten constant, and induction factor, and rate of onset of induction of drug clearance were 0.33 (0.26, 0.48) L/kg, 21.8 (16.3, 28.0) mg/kg/hour, 94.6 (48.8, 153.0) mg/L, 1.28 (1.06, 1.66), and 0.0038 (0.0019, 0.0058) hour(-1), respectively.

CONCLUSION

The results of this study are similar to previous pharmacokinetic evaluations using the Abbottbase PKS system but suggest that earlier analyses were suboptimal.

The control of prostate-specific antigen expression and gene regulation by pharmacological agents

Prostate-specific antigen is a serine protease that is a member of the kallikrein family. It is widely used as an indicator of tumor burden and as a surrogate marker for disease progression in men with androgen-independent prostate cancer. It has been shown that the expression and/or secretion of this glycoprotein can be regulated by pharmacological agents. The effects of these agents on PSA may be independent of their effects on cell growth. For example, a pharmacological agent may down-regulate PSA expression/secretion but have no effect on tumor cell growth. In this case, a patient receiving this therapeutic agent might be falsely considered as having a clinical response. Alternatively, an agent might up-regulate PSA expression/secretion and have an inhibitory effect on cell growth. A patient receiving this therapeutic agent might be diagnosed with progressive disease unless an alternative method for assessing tumor burden is used. Thus, when an agent is to be evaluated in a clinical trial utilizing PSA as a marker for disease progression, it is important to prospectively test whether the agent has an effect on PSA expression and/or secretion. In addition, it is equally important to understand how these regulatory effects relate to cell growth. The purpose of this review is to describe several agents that have been tested for their regulatory effects on PSA and to discuss potential mechanisms of by which this regulation may occur. The implications of these findings in the evaluation of new agents in androgen-independent prostate cancer will be considered.

Comparative study of the clinical efficacy of two dosing regimens of flutamide

PURPOSE

We performed a randomized trial to compare the efficacy and toxicity of a new dose of flutamide (500 mg QD) with the currently recommended dose (250 mg q8h) in the treatment of advanced prostate cancer. The primary endpoints were percent of patients having normalization of prostate specific antigen (PSA), time to normalization, and percent change from baseline. Secondary endpoints were quality of life and toxicity.

PATIENTS

Altogether, 440 men aged 46 to 94 years (mean 71 years) with confirmed stage M(1) disease, documented PSA rise >0.2 ng/mL, ECOG status 0 to 2, no second neoplasm, no liver function tests > or = 1.5-fold normal values, and no previous treatment for metastatic disease were entered in the trial.

RESULTS

The PSA normalized by week 12 in 71% of the patients receiving 500-mg dose and 75% of those receiving the standard dose. The percent change in PSA was 89% and 96%, respectively. The treatment groups were not significantly different with respect to the incidence of adverse events: 71% v 68% in the 500-mg and 250-mg arms, respectively (P = 0.337).

CONCLUSIONS

When combined with castration, 500 mg of flutamide appears to be equally effective in lowering serum PSA and is not significantly more toxic than conventional dosing. The use of 500 mg QD instead of the standard 250 mg q8h would result in a cost savings of 30%.

Isolated hepatic perfusion for unresectable hepatic metastases from colorectal cancer

BACKGROUND

Unresectable colorectal liver metastases are a significant clinical problem. Isolated hepatic perfusion (IHP) is a regional treatment technique that delivers high dose chemotherapy, biologic agents, and hyperthermia via a completely isolated vascular recirculating perfusion circuit as a means of regionally treating liver tumors. This study presents our results of IHP with tumor necrosis factor (TNF) plus melphalan or IHP with melphalan alone followed by infusional floxuridine (FUDR) and leucovorin in patients with advanced or refractory unresectable hepatic colorectal metastases.

METHODS

Fifty-one patients with unresectable colorectal hepatic metastases underwent a 60-minute IHP with 1.5 mg/kg melphalan and hyperthermia (39 degrees C to 40 degrees C). Thirty-two patients received IHP with 1 mg TNF with melphalan and 19 patients had IHP with melphalan alone followed by monthly hepatic intra-arterial infusional (HAI) FUDR (0.2 mg/kg/day) and leucovorin (15 mg/M(2)/day) for 14 days monthly for up to 12 months. Twenty-six patients failed 1 or more previous treatment regimens for established hepatic metastases and 27 had greater than 25% hepatic replacement (PHR) by tumor. Patients were monitored for response, toxicity, and survival.

RESULTS

There was 1 perioperative death (2%), and only 2 patients (4%) had measurable perfusate leak during IHP (both less than 4%). In the 32 patients treated with IHP alone there were no detectable systemic TNF or melphalan levels during perfusion. The overall objective radiographic response rate (all partial [PR]) was 76% (38 of 50 assessable patients) with a median duration of 10.5 months (range, 2 to 21 months). Twenty-four of 31 patients (77%) had a PR after IHP alone and 14 of 19 (74%) after IHP with postperfusion HAI. Median duration of response was 8.5 months after IHP alone and 14.5 months after IHP and HAI; median survival was 16 and 27 months, respectively. There were 18 PRs in 26 patients (69%) whose prior therapy had failed and 18 PRs in 27 patients (67%) with PHR of 25 or greater.

CONCLUSIONS

IHP can be performed with acceptably low morbidity and has significant antitumor activity in patients with unresectable hepatic metastases from colorectal cancer including those with refractory disease or PHR of 25 or greater. HAI appears to prolong the duration of response after IHP, and this combined treatment strategy deserves additional clinical evaluation as a therapeutic modality in this setting.

Phase I study of infusional paclitaxel in combination with the P-glycoprotein antagonist PSC 833

PURPOSE

PSC 833 (valspodar) is a second-generation P-glycoprotein (Pgp) antagonist developed to reverse multidrug resistance. We conducted a phase I study of a 7-day oral administration of PSC 833 in combination with paclitaxel, administered as a 96-hour continuous infusion.

PATIENTS AND METHODS

Fifty patients with advanced cancer were enrolled onto the trial. PSC 833 was administered orally for 7 days, beginning 72 hours before the start of the paclitaxel infusion. Paclitaxel dose reductions were planned because of the pharmacokinetic interactions known to occur with PSC 833.

RESULTS

In combination with PSC 833, maximum-tolerated doses were defined as paclitaxel 13.1 mg/m(2)/d continuous intravenous infusion (CIVI) for 4 days without filgrastim, and paclitaxel 17.5 mg/m(2)/d CIVI for 4 days with filgrastim support. Dose-limiting toxicity for the combination was neutropenia. Statistical analysis of cohorts revealed similar mean steady-state concentrations (C(pss)) and areas under the concentration-versus-time curve (AUCs) when patients received paclitaxel doses of 13.1 or 17.5 mg/m(2)/d for 4 days with PSC 833, as when they received a paclitaxel dose of 35 mg/m(2)/d for 4 days without PSC 833. However, the effect of PSC 833 on paclitaxel pharmacokinetics varied greatly among individual patients, although a surrogate assay using CD56+ cells suggested inhibition of Pgp was complete or nearly complete at low concentrations of PSC 833. Responses occurred in three of four patients with non-small-cell lung cancer, and clinical benefit occurred in five of 10 patients with ovarian carcinoma.

CONCLUSION

PSC 833 in combination with paclitaxel can be administered safely to patients provided the paclitaxel dose is reduced to compensate for the pharmacokinetic interaction. Surrogate studies with CD56+ cells indicate that the maximum-tolerated dose for PSC 833 gives serum levels much higher than those required to block Pgp. The variability in paclitaxel pharmacokinetics, despite complete inhibition of Pgp in the surrogate assay, suggests that other mechanisms, most likely related to P450, contribute to the pharmacokinetic interaction. Future development of combinations such as this should include strategies to predict pharmacokinetics of the chemotherapeutic agent. This in turn will facilitate dosing to achieve comparable CPss and AUCs.

Concurrent paclitaxel and radiation in the treatment of locally advanced head and neck cancer

PURPOSE

To determine the feasibility of an organ preservation regimen consisting of infusional paclitaxel administered concurrently with radiotherapy to patients with locally advanced head and neck squamous cell carcinoma (HNSCC).

PATIENTS AND METHODS

Thirty-three previously untreated patients with stage III or IV tumors were enrolled onto the study. Paclitaxel was administered as a 120-hour continuous infusion every 3 weeks during the course of radiation therapy. Sixteen patients received a paclitaxel dose of 105 mg/m(2), and 17 patients received 120 mg/m(2). Radiation was delivered in a standard format at 1.8 Gy/d to a total dose of 70.2 to 72 Gy.

RESULTS

Three months after therapy, a 76% complete response (CR) at the primary site and a 70% overall CR was achieved. At 36 months, locoregional control was 55.7%, overall survival was 57.8%, and disease-free survival was 51.1%. The median survival duration for all 33 patients was greater than 50 months at the time of this report. Local toxicities including mucositis, dysphagia, and skin reactions were severe but tolerable. All patients retained functional speech, and all but four patients were swallowing food 3 months after treatment. Steady-state plasma concentrations for paclitaxel were not achieved during a 120-hour infusion, suggesting a nonlinear process. Tumor volume quantified by pretreatment computerized tomography imaging was associated with likelihood of response and survival.

CONCLUSION

Paclitaxel administered as a 120-hour continuous infusion in combination with radiotherapy is a feasible and promising treatment for patients with advanced HNSCC.

Human CYP1B1 and anticancer agent metabolism: mechanism for tumor-specific drug inactivation?

The cytochrome P450 1B1 (CYP1B1) is involved in the metabolism of procarcinogens and xenobiotics. Human CYP1B1 protein has been detected in a variety of tumors but is not detected in adjacent normal tissues or in liver. This suggests that CYP1B1 could biotransform anticancer agents specifically in the target cells. The interaction between CYP1B1 and 12 commonly used anticancer drugs was screened using an ethoxyresorufin deethylase assay. Four agents were competitive inhibitors of CYP1B1 activity: flutamide (K(i) = 1.0 microM), paclitaxel (K(i) = 31.6 microM), mitoxantrone (K(i) = 11.6 microM), and docetaxel (K(i) = 28.0 microM). Doxorubicin (K(i) = 2.6 microM) and daunomycin (K(i) = 2.1 microM) were mixed inhibitors, while tamoxifen was a noncompetitive inhibitor (K(i) = 5.0 microM). Vinblastine, vincristine, 5-fluorouracil, etoposide, and cyclophosphamide did not inhibit CYP1B1 activity. In vitro incubations with flutamide and CYP1B1 produced a metabolite consistent with 2-hydroxyflutamide. Comparison of kinetic parameters (K(m), K(i), V(max)) for flutamide 2-hydroxylation by CYP1B1, CYP1A1, and CYP1A2 indicate that CYP1B1 could play a major role for flutamide biotransformation in tumors. The results obtained indicate that several anticancer agents inhibit CYP1B1 activity. Drug inactivation by CYP1B1 may represent a novel mechanism of resistance, influencing the clinical outcome of chemotherapy.

Phase I clinical trial of oral COL-3, a matrix metalloproteinase inhibitor, in patients with refractory metastatic cancer

PURPOSE

This phase I clinical trial was designed to determine the maximum-tolerated dose and dose-limiting toxicities of the matrix metalloproteinase (MMP) inhibitor COL-3 in patients with refractory solid tumors.

PATIENTS AND METHODS

Thirty-five patients with different cancer types were enrolled. COL-3 doses were escalated from 36 mg/m2/d in successive cohorts of at least three patients. Circulating levels of MMP-2, MMP-9, vascular endothelial growth factor, and basic fibroblast growth factor were assessed during treatment. Pharmacokinetic parameters were assessed for single and multiple doses of drug.

RESULTS

Cutaneous phototoxicity was dose-limiting at 98 mg/m2/d. With the use of prophylactic sunblock, COL-3 was well tolerated at 70 mg/m2/d. The dose of 36 mg/m2/d was well tolerated without the use of sunblock. Other toxicities that did not seem to be related to dose or pharmacokinetics included anemia, anorexia, constipation, dizziness, elevated liver function test results, fever, headache, heartburn, nausea, vomiting, peripheral and central neurotoxicities, fatigue, and three cases of drug-induced lupus. Disease stabilization for periods of 26+ months, 8 months, and 6 months were seen in hemangioendothelioma, Sertoli-Leydig cell tumor, and fibrosarcoma, respectively. There was a potentially statistically significant relationship between changes in plasma MMP-2 levels and cumulative doses of drug when progressive disease patients were compared with those with stable disease or toxicity (P = .042).

CONCLUSION

COL-3 induced disease stabilization in several patients who had a nonepithelial type of malignancy. Phototoxicity was dose-limiting. We recommend the dose of 36 mg/m2/d for phase II trials.

Suramin administration is associated with a decrease in serum calcium levels

Suramin has been shown to have an effect on bone resorption in in vitro models. It is not clear if a similar effect is seen in patients treated with suramin. The clinical effect of suramin treatment on total serum calcium was examined in two groups of patients with hormone-refractory prostate cancer. In all, 28 patients in group 1 were examined within 2 weeks before and 2 weeks after suramin treatment and 72 patients in group 2 were examined within 2 weeks before, during, and after treatment with suramin. In addition, calcium controls spiked with suramin were run in three different commercially available assays for evaluation of the effect of suramin dose on calcium determination. Group 1 patients showed a decrease in serum calcium after treatment with suramin. The mean uncorrected serum calcium level was 2.29 +/- 0.025 mmol/l before treatment and 2.09 +/- 0.025 mmol/l after treatment (P < 0.0001, paired Wilcoxon test). The mean serum calcium value corrected for albumin was 2.33 +/- 0.02 mmol/l before treatment and 2.24 +/- 0.02 mmol/l after treatment (P = 0.0022, paired Wilcoxon test). Group 2 patients also displayed a decrease in serum calcium after treatment with suramin. The mean baseline value was 2.23 mmol/l (median 2.26 mmol/l, range 1.20-2.54 mmol/l). The mean level of serum calcium corrected for albumin as determined at the end of treatment was 2.14 mmol/l (median 2.16 mmol/l, range 0.98 2.46 mmol/l). In all, 48 patients for whom pre- and post-treatment values were available for analysis displayed a median calcium decrease of 0.09 mmol/l (P = 0.0005, Wilcoxon signed-rank test for the null hypothesis of no change). For 68 patients in group 2, data on serial serum calcium measurements during treatment were available for analysis. A projected median decrease in serum calcium of 0.06 mmol/l (range 0.43 to 0.72 mmol/l) over an 8-week interval of suramin therapy was found. Overall, 47 of the 68 slopes were negative (P = 0.0022, Wilcoxon signed-rank test). Nine patients were treated with suramin for less than 6 weeks. These patients' calcium levels were significantly higher than those of 50 patients treated for longer periods (median value 2.24 versus 2.16 mmol/l, P = 0.035, Wilcoxon rank-sum test). No correlation was found between suramin dose and calcium level using the Kodak Ektachem, Hitachi 914, or Synchron Clinical System CX3 method. In conclusion, suramin treatment was consistently associated with decreases in serum calcium in two groups of patients with hormone-refractory cancer. Suramin placed in calcium controls did not affect calcium determination using three commercially available methods.

Hyperinducibility of hypoxia-responsive genes without p53/p21-dependent checkpoint in aggressive prostate cancer

Hypoxia limits tumor growth but selects for higher metastatic potential. We tested the functional activity of hypoxia-inducible factor-1 (HIF-1) in prostate cell lines ranging from normal epithelial cells (PrEC), hormone-dependent LNCaP, hormone-independent DU145, PC-3 to highly metastatic PC-3M cancer cell lines. We found that HIF-1-stimulated transcription was the lowest in PrEC and LNCaP cells and the highest in PC-3M cells. The induction by hypoxia of the HIF-1 dependent genes Cap43 and GAPDH was the highest in the most aggressive PC-3M cancer cells. Because these advanced prostate cancer cell lines have lost p53 function, this further shifts a balance from p53 to HIF-1 transcriptional regulation, and a high ratio of HIF-1-dependent:p53-dependent transcription was a marker of the advanced malignant phenotype. Transient transfection of HIF-1alpha expression vector induced transcription from p21 promoter construct in prostate cancer cell lines. Furthermore, hypoxia slightly induced p21 mRNA in these cells. However, neither expression of p21 nor hypoxia caused growth arrest in PC-3M cells. Therefore, high inducibility of HIF-1-dependent genes, loss of p53 functions with high ratio of HIF-1-dependent:p53-dependent transcription, and loss of sensitivity to p21 inhibition is a part of hypoxic phenotype associated with aggressive cancer behavior.

Effects of ligand activation of peroxisome proliferator-activated receptor gamma in human prostate cancer

Peroxisome proliferator-activated receptor gamma (PPARgamma) is a nuclear hormone receptor that plays a key role in the differentiation of adipocytes. Activation of this receptor in liposarcomas and breast and colon cancer cells also induces cell growth inhibition and differentiation. In the present study, we show that PPARgamma is expressed in human prostate adenocarcinomas and cell lines derived from these tumors. Activation of this receptor with specific ligands exerts an inhibitory effect on the growth of prostate cancer cell lines. Further, we show that prostate cancer and cell lines do not have intragenic mutations in the PPARgamma gene, although 40% of the informative tumors have hemizygous deletions of this gene. Based on our preclinical data, we conducted a phase II clinical study in patients with advanced prostate cancer using troglitazone, a PPARgamma ligand used for the treatment of type 2 diabetes. Forty-one men with histologically confirmed prostate cancer and no symptomatic metastatic disease were treated orally with troglitazone. An unexpectedly high incidence of prolonged stabilization of prostate-specific antigen was seen in patients treated with troglitazone. In addition, one patient had a dramatic decrease in serum prostate-specific antigen to nearly undetectable levels. These data suggest that PPARgamma may serve as a biological modifier in human prostate cancer and its therapeutic potential in this disease should be further investigated.

A high-performance liquid chromatography method using ultraviolet and fluorescence detection for the quantitation of UCN-01, 7-hydroxystaurosporine, from human plasma and saliva

UCN-01, 7-hydroxystaurosporine, is an antagonist of protein kinase C, as well as causing cell cycle arrest. We developed and validated an HPLC assay method for the quantitation of UCN-01. Plasma and saliva standard curves were prepared at concentrations ranging from 0.2 to 20.0 microgram/mL and 4.0 to 200.0 ng/mL, respectively. The sample preparation consisted of acetonitrile precipitation. Separation was accomplished on a phenyl column and a C-18 precolumn insert utilizing a gradient-profile consisting of ammonium acetate and acetonitrile. UV detection was set at 295 nm for UCN-01 and 323 nm for umbelliferone, the internal standard. For fluorescence detection, excitation occurred at 290 nm, while emission was at 400 nm. The retention times were around 4 min for umbelliferone and 9.1 for UCN-01. Inter- and intra-assay errors of accuracy were less than 7. 0% and 10.7%, respectively, for the plasma standard curve and less than 7.1% and 6.7%, respectively, for the saliva standard curve. The recoveries of UCN-01 and umbelliferone from saliva were 81.4 +/- 0. 9% and 106.3 +/- 10.2%, respectively. The recovery of UCN-01 from plasma was 97.9 +/- 7.1% and for umbelliferone was 103.3 +/- 2.3%. This method is suitable for quantifying UCN-01 in patient samples and further characterizing the clinical pharmacology of this compound. Published in 2000 by John Wiley & Sons, Ltd.

High-performance liquid chromatography with mass spectrometry detection for quantitating COL-3, a chemically modified tetracycline, in human plasma

COL-3, 6-deoxy-6-demethyl-4-dedimethylamino-tetracycline, is a matrix metalloproteinase inhibitor. A specific and sensitive analytical method was necessary to quantitate the analyte in human plasma. High-performance liquid chromatography with atmospheric pressure chemical ionization mass spectrometry detection was utilized to quantitate COL-3 from 30 to 10,000 ng/ml in two calibration curves: 30-1,500 and 400-10,000 ng/ml. The sample preparation consisted of acetonitrile precipitation for all plasma samples. COL-3 is separated on a Waters Symmetry C-18 (2.1 x 150 mm) column with oxalic acid (0.01 M, pH 2.2)-acetonitrile mobile phase. The total run time was 23 min. Identification of COL-3 and the internal standard was through positive chemical ionization and selective ion monitoring. A quantifying and qualifying ion for COL-3 is used to verify the presence of COL-3 in patient samples. Inter- and intra-run mean percent errors for all of the quality controls were less than 18.3', and relative standard deviations were all less than 14.9'% Recovery of COL-3 and the internal standard was approximately 55 and 72', respectively. Freeze thaw stability of COL-3 was variable. This method is suitable for quantifying COL-3 in patient samples and to further characterize the clinical pharmacology of this compound.

Activity of thalidomide in AIDS-related Kaposi's sarcoma

PURPOSE

To assess the toxicity and activity of oral thalidomide in Kaposi's sarcoma (KS) in a phase II dose-escalation study.

PATIENTS AND METHODS

Human immunodeficiency virus (HIV)-seropositive patients with biopsy-confirmed KS that progressed over the 2 months before enrollment received an initial dose of 200 mg/d of oral thalidomide in a phase II study. The dose was increased to a maximum of 1,000 mg/d for up to 1 year. Anti-HIV therapy was maintained during the study period. Toxicity, tumor response, immunologic and angiogenic factors, and virologic parameters were assessed.

RESULTS

Twenty patients aged 29 to 49 years with a median CD4 count of 246 cells/mm(3) (range, 14 to 646 cells/mm(3)) were enrolled. All patients were assessable for toxicity, and 17 for response. Drowsiness in nine and depression in seven patients were the most frequent toxicities observed. Eight (47%; 95% confidence interval [CI], 23% to 72%) of the 17 assessable patients achieved a partial response, and an additional two patients had stable disease. Based on all 20 patients treated, the response rate was 40% (95% CI, 19% to 64%). The median thalidomide dose at the time of response was 500 mg/d (range, 400 to 1,000 mg/d). The median duration of drug treatment was 6.3 months, and the median time to progression was 7.3 months.

CONCLUSION

Oral thalidomide was tolerated in this population at doses up to 1,000 mg/d for as long as 12 months and was found to induce clinically meaningful anti-KS responses in a sizable subset of the patients. Additional studies of this agent in KS are warranted.

Endothelial monocyte activating polypeptide II induces endothelial cell apoptosis and may inhibit tumor angiogenesis

Endothelial monocyte activating polypeptide II (EMAP-II) is a tumor-derived cytokine with potent effects on endothelial cells in vitro and in vivo including upregulation of tissue factor and the sensitization of human melanoma to systemic TNF treatment via its effects on the tumor vasculature. We investigated the effects of EMAP-II on tumor growth, angiogenesis, vasculogenesis, and apoptosis. EMAP-II inhibited endothelial cell proliferation, vasculogenesis, and neovessel formation. In vivo growth of human melanoma lines expressing high amounts of EMAP-II demonstrated slower growth, smaller tumors, and increased amounts of tumor necrosis than those expressing lower amounts of EMAP-II. EMAP-II induced endothelial-cell-specific apoptosis via a pathway that includes upregulation of the Fas-associated death domain and downregulation of Bcl-2. EMAP-II appears to have important effects on angiogenesis and may play a role in regulating tumor vascular growth.

The angiogenesis inhibitor, endostatin, does not affect murine cutaneous wound healing

BACKGROUND

Endostatin is a potent angiogenesis inhibitor, which is currently being used in Phase I trials as an antitumor agent. The purpose of this study was to determine whether endostatin has an effect on wound healing in a murine model.

MATERIALS AND METHODS

The function of endostatin was confirmed using a human microvascular endothelial cell (HMVEC) proliferation assay in which cells are treated for 4 days with growth media plus or minus endostatin. Full-thickness incisions were made on the dorsum of athymic nude mice and closed primarily with skin staples. PVA sponges were implanted in some wounds to determine vascular ingrowth. Subsequently, mice were treated with recombinant human endostatin at 20 mg/kg/day or 50 mg/kg/dose BID versus control for a total of 14 days. On Days 2, 4, 8, 12, and 16, three mice per group had serum samples drawn and were sacrificed. Perpendicular breaking strength (N) was determined using an Instron 5540 tensometer. Wound strength was determined by dividing breaking strength by wound area (N/cm(2)). Vascular density in sponges was determined using CD31 immunohistochemistry. Serum endostatin concentrations were determined using a commercially available ELISA kit.

RESULTS

Endostatin caused a significant reduction of endothelial cell proliferation after 4 days compared to media alone (72%, P = 0.031). At all time points tested, there was no statistical difference in the wound-breaking strength between endostatin and control-treated mice at either the low or high dose. Serum endostatin levels were consistently 10-fold higher in endostatin-treated mice than in controls. No differences in vascular density were seen in endostatin versus control-treated mice as determined by CD31 immunohistochemistry of PVA sponges.

CONCLUSION

Therapy with human endostatin does not induce a significant decrease in breaking strength of cutaneous wounds in mice.

TNP-470: an angiogenesis inhibitor in clinical development for cancer

TNP-470, an analogue of fumagillin, has been shown to inhibit angiogenesis in vitro and in vivo. In 1992, TNP-470 entered clinical development for cancer as an anti-angiogenic agent. It is currently in Phase I/II trials in Kaposi's sarcoma, renal cell carcinoma, brain cancer, breast cancer, cervical cancer and prostate cancer. In early clinical reports, TNP-470 is tolerated up to 177 mg/m(2) with neurotoxic effects (fatigue, vertigo, ataxia, and loss of concentration) being the principal dose limiting toxicity (DLT). Terminal half-life values are short and have shown intermittent and intrapatient variation (range: 0.05 - 1.07 h). Recently, mechanistic studies have identified cell cycle mediators and the protein methionine aminopeptidase-2 (MetAP-2) as molecular targets of TNP-470 and fumagillin. Animal studies confirm some toxic effects on normal angiogenic processes such as the female reproductive system and wound healing, which will require caution and close monitoring in the clinic. TNP-470 is one of the first anti-angiogenic compounds to enter clinical trials, making it a valuable prototype for future trials of angiogenesis inhibitors in oncology.

UCN-01, a protein kinase C inhibitor, inhibits endothelial cell proliferation and angiogenic hypoxic response

Angiogenesis is required for tumor formation and growth; inhibition of angiogenesis is a promising new approach in cancer therapy. UCN-01, a protein kinase C (PKC) inhibitor, induces growth arrest and apoptosis in cancer cells and was recently introduced in a phase I clinical trial. We demonstrate that UCN-01, at concentrations lower than those necessary to inhibit cancer cell growth, inhibit proliferation of human endothelial cells in vitro. Moreover, UCN-01, at concentrations as low as 32 nM, prevent microvessel outgrowth from explant cultures of rat aortic rings. Since hypoxia activates hypoxia-inducible factor (HIF-1)-dependent transcription in cancer cells that, in a paracrine fashion, drive tumor angiogenesis, we investigated the effects of UCN-01 on HIF-1-responsive promoter constructs. We report that, in addition to direct inhibitory effects on endothelial cell growth, UCN-01 abrogates hypoxia-mediated transactivation of HIF-1-responsive promoters in a prostate cancer cell line. We conclude that UCN-01, at clinically relevant concentrations, exerts an anti-neovascularization effect by blocking two important steps in vessel formation: (1) the response of cancer cells to hypoxia, and (2) endothelial cell proliferation.

A phase I study of combination therapy with immunotoxins IgG-HD37-deglycosylated ricin A chain (dgA) and IgG-RFB4-dgA (Combotox) in patients with refractory CD19(+), CD22(+) B cell lymphoma

This study used an 8-day continuous infusion regimen of a 1:1 mixture of two immunotoxins (ITs) prepared from deglycosylated ricin A chain (dgA) conjugated to monoclonal antibodies directed against CD22 (RFB4-dgA) and CD19 (HD37-dgA; Combotox) in a Phase I trial involving 22 patients with refractory B cell lymphoma to determine the maximum tolerated dose, clinical pharmacology, and toxicity profile and to characterize any clinical responses. Adult patients received a continuous infusion of Combotox at 10, 20, or 30 mg/m2/192 h. No intrapatient dose escalation was permitted. Patients with > or =50 circulating tumor cells (CTCs)/mm3 in peripheral blood tolerated all doses without major toxicity. The maximum level of serum IT (Cmax) achieved in this group was 345 ng/ml of RFB4-dgA and 660 ng/ml of HD37-dgA (1005 ng/ml of Combotox). In contrast, patients without CTCs (<50/mm3) had unpredictable clinical courses that included two deaths probably related to the IT. Additionally, patients exhibited a significant potential for association between mortality and a history of either autologous bone marrow or peripheral blood stem cell transplants (P2 = 0.003) and between mortality and a history of radiation therapy (P2 = 0.036). In patients with CTCs, prior therapies appeared to have little impact on toxicity. Subsequent evaluation of the ITs revealed biochemical heterogeneity between two lots of HD37-dgA. In addition, HD37-dgA thawed at the study site tended to contain significant particulates, which were not apparent in matched controls stored at the originating site. This suggests that a tendency to aggregate may have resulted from shipping, storage, and handling of the IT that occurred prior to preparation for administration. It is not clear to what extent, if any, the aggregation of HD37-dgA IT was related to the encountered clinical toxicities; however, the potential to aggregate does suggest one possible basis for problems in our clinical experience with HD37-dgA and leads us to the conclusion that non-aggregate-forming formulations for these ITs should be pursued prior to future clinical trials.

Efficacy of microtubule-active drugs followed by ketoconazole in human metastatic prostate cancer cell lines

PURPOSE

Once a relapse occurs following primary endocrine treatment, metastatic prostate cancer is one of the most therapy-resistant human neoplasms. Ketoconazole is used for complete androgen deprivation, and recent data suggest it has direct activity against prostate cancer cells.

MATERIALS AND METHODS

LNCaP, DU145, and PC3 cells, human prostate cancer cell lines, and HL60, a human leukemia cell line, were lysed and soluble proteins were harvested. Cells were plated in 96-well flat bottom plates and then exposed to the pharmacological agents, ketoconazole, vinblastine and paclitaxel. DNA synthesis was monitored by 3H-thymidine incorporation.

RESULTS

We demonstrate that ketoconazole exerts a cytostatic effect on a panel of human prostate cancer cell lines, with IC50 of 4 to 5 microg./ml., 12 microg./ml., and 25 microg./ml. for LNCaP, PC3/PC3M, and DU145 cells, respectively. On the other hand, using microtubule-active drugs, vinblastine and paclitaxel, we found that PC3M and PC3 cells were more resistant than either DU145 or LNCaP cells. This resistance was associated with a lesser degree of Raf-1 and Bcl-2 phosphorylation following exposure to microtubule-active drugs. Combinations of microtubule-active drugs with ketoconazole were a beneficial treatment in DU145 cancer cells. Furthermore, ketoconazole blocked recovery of all the prostate cancer cell lines following 24 hours-pulse treatment with vinblastine.

CONCLUSION

Pulse-administration of vinblastine followed by continuous administration of ketoconazole warrants investigation in the treatment of hormone-independent metastatic prostate cancer.

Endostatin inhibits microvessel formation in the ex vivo rat aortic ring angiogenesis assay

Endostatin has demonstrated potent antiangiogenic and antitumor activity in mouse models. We have investigated the ex vivo rat aortic ring assay and a human vein model to assess the biological activity of murine and human endostatin. Rat aortic rings were exposed to recombinant murine endostatin (Spodoptera frugipera; Calbiochem, San Diego, CA) or recombinant human endostatin (Pichia pastoris; EntreMed, Rockville, MD). After 5 days, murine endostatin (500 microgram/ml) demonstrated inhibition of microvessel outgrowth with dose-dependent effects (down to 16 microgram/ml). No significant inhibition was observed with human endostatin in the rat assay. Human endostatin at 250 and 500 microgram/ml inhibited outgrowths from human saphenous vein rings after a 14-day incubation. Electron microscopy assessed the formation of basal lamina, confirming that the microvessels were progenitors of patent vessels. Immunostaining for Factor VIII or CD34 demonstrated that the microvessel cells were endothelial. BrdU incorporation assays supported the presence of proliferating endothelial cells, correlating with neovascularization from the aortic wall. We conclude that the rat aortic ring assay confirms the antiangiogenic activity of murine but not human endostatin, suggesting that the model may have species specificity. However, the human form shows biological activity against human vascular tissue.

Phase II trial of the antiangiogenic agent thalidomide in patients with recurrent high-grade gliomas

PURPOSE

Little progress has been made in the treatment of adult high-grade gliomas over the last two decades, thus necessitating a search for novel therapeutic strategies. Malignant gliomas are vascular or angiogenic tumors, which leads to the supposition that angiogenesis inhibition may represent a potentially promising strategy in the treatment of these tumors. We present the results of a phase II trial of thalidomide, a putative inhibitor of angiogenesis, in the treatment of adults with previously irradiated, recurrent high-grade gliomas.

PATIENTS AND METHODS

Patients with a histologic diagnosis of anaplastic mixed glioma, anaplastic astrocytoma, or glioblastoma multiforme who had radiographic demonstration of tumor progression after standard external-beam radiotherapy with or without chemotherapy were eligible. Patients were initially treated with thalidomide 800 mg/d with increases in dose by 200 mg/d every 2 weeks until a final daily dose of 1,200 mg was achieved. Patients were evaluated every 8 weeks for response by both clinical and radiographic criteria.

RESULTS

A total of 39 patients were accrued, with 36 patients being assessable for both toxicity and response. Thalidomide was well tolerated, with constipation and sedation being the major toxicities. One patient developed a grade 2 peripheral neuropathy after treatment with thalidomide for nearly a year. There were two objective radiographic partial responses (6%), two minor responses (6%), and 12 patients with stable disease (33%). Eight patients were alive more than 1 year after starting thalidomide, although almost all with tumor progression. Changes in serum levels of basic fibroblastic growth factor (bFGF) were correlated with time to tumor progression and overall survival.

CONCLUSION

Thalidomide is a generally well-tolerated drug that may have antitumor activity in a minority of patients with recurrent high-grade gliomas. Future studies will better define the usefulness of thalidomide in newly diagnosed patients with malignant gliomas and in combination with radiotherapy and chemotherapy. Additionally, studies will be needed to confirm the potential utility of changes in serum bFGF as a marker of antiangiogenic activity and/or glioma growth.

Modulation of clinical drug resistance in a B cell lymphoma patient by the protein kinase inhibitor 7-hydroxystaurosporine: presentation of a novel therapeutic paradigm

Emerging evidence suggests that apoptosis is an important mechanism of tumor cell death from antineoplastic therapy. 7-hydroxystaurosporine (UCN-01) is a novel protein kinase inhibitor that increases chemotherapy-induced apoptosis in vitro and is in early phases of clinical development. In this report, we present a 68-year-old patient with chemotherapy-resistant lymphoma treated with UCN-01 and chemotherapy. He had a stage IV plasmacytoid lymphoma that failed to enter remission with high-dose EPOCH II (etoposide, prednisone, vincristine, cyclophosphamide, doxorubicin) chemotherapy. Due to disease progression and transformation to large cell lymphoma in the liver and bone marrow, he received UCN-01. Four weeks later, he received "standard-dose" EPOCH because of progression, developed severe neutropenia for 9 days, and expired from Candida sepsis on day 23. At autopsy, there was no histological evidence of residual lymphoma, although PCR for immunoglobulin gene rearrangement analysis revealed a faint clonal band in two of six nodes but none in the liver. Significantly, no B cells were detected by immunohistochemistry in lymph nodes, and a polyclonal ladder pattern associated with the presence of normal B cells was not seen in the immunoglobulin gene rearrangement PCR assay. Profound peripheral lymphopenia (50 cells/microliter) was also observed. Pharmacokinetics showed UCN-01 salivary concentrations, a surrogate for free drug concentrations, to be within an effective range in vitro (45 nmol/L) as a modulator of DNA-damaging agent cytotoxicity. In vitro, UCN-01 is synergistic with multiple cytotoxic agents and increases fludarabine-induced apoptosis in a human breast cell line. These results suggest that UCN-01 sensitized the lymphoma to the cytotoxic effects of EPOCH, possibly by modulating the "threshold" for apoptosis, and may illustrate a new paradigm for reversal of drug resistance.