Biomedical subjects

Parkash S Gill

Publications and source records attributed to Parkash S Gill.

At least 19 recordsLinked to original sources

PubMed2006

EphB4 provides survival advantage to squamous cell carcinoma of the head and neck.

The receptor tyrosine kinase EphB4 and its ligand EphrinB2 play critical roles in blood vessel maturation, and are frequently overexpressed in a wide variety of cancers. We studied the aberrant expression and biological role of EphB4 in head and neck squamous cell carcinoma (HNSCC). We tested the effect of EphB4-specific siRNA and antisense oligonucleotides (AS-ODN) on cell growth, migration and invasion, and the effect of EphB4 AS-ODN on tumor growth in vivo. All HNSCC tumor samples express EphB4 and levels of expression correlate directly with higher stage and lymph node metastasis. Six of 7 (86%) HNSCC cell lines express EphB4, which is induced either by EGFR activation or by EPHB4 gene amplification. EphrinB2 was expressed in 65% tumors and 5 of 7 (71%) cell lines. EphB4 provides survival advantage to tumor cells in that EphB4 siRNA and AS-ODN significantly inhibit tumor cell viability, induce apoptosis, activate caspase-8, and sensitize cells to TRAIL-induced cell death. Furthermore, EphB4-specific AS-ODN significantly inhibits the growth of HNSCC tumor xenografts in vivo. Expression of EphB4 in HNSCC tumor cells confers survival and invasive properties, and thereby provides a strong rationale for targeting EphB4 as novel therapy for HNSCC.

Animals↗

PubMed2006

Phase I study of antisense oligonucleotide against vascular endothelial growth factor: decrease in plasma vascular endothelial growth factor with potential clinical efficacy.

PURPOSE: Vascular endothelial growth factor antisense (VEGF-AS) is an antisense oligonucleotide that targets VEGF, inhibiting angiogenesis and tumor cell proliferation. This study established the safety, biologic effects, and pharmacokinetics of VEGF-AS in 51 patients with advanced malignancies. METHODS: VEGF-AS was administered as a 2-hour infusion daily for 5 consecutive days for only one cycle on the first four dose levels, and then administered daily for 5 days every other week for up to 4 months on subsequent levels. Pharmacokinetics, tumor response, and the effect on plasma VEGF levels were determined. RESULTS: The maximum-tolerated dose was 200 mg/m2. Dose-limiting toxicities included grade 4 fever, and pulmonary embolism in one patient each at 250 mg/m2. Mild anemia, fever, fatigue, and gastrointestinal complaints were the most common adverse events. VEGF-AS t(1/2beta) (beta-phase terminal half-life of drug concentration) was 2.25 hours (range, 1.97 to 2.95 hours). Mean plasma VEGF-A (P = .002) and VEGF-C (P = .01) levels decreased 24 hours postinfusion, with a trend towards greater decreases at higher dose levels. At the maximum-tolerated dose, five of six patients demonstrated reductions in plasma VEGF. Clinical responses included complete remission in one patient with AIDS-Kaposi's sarcoma, a mixed but dramatic response in one patient with cutaneous T-cell lymphoma, and prolongation of progression-free survival compared with that obtained on the immediate prior regimen in six patients (12%) with renal cell, bronchoalveolar, small cell lung, thyroid, and ovarian carcinomas, and chondrosarcoma, respectively. CONCLUSION: VEGF-AS was well tolerated, with biologic effects and preliminary evidence of clinical efficacy.

Adult↗

PubMed2006

The association between elevated EphB4 expression, smoking status, and advanced-stage disease in patients with head and neck squamous cell carcinoma.

OBJECTIVE: To examine the expression of EphB4 in tumor tissue, surrounding normal tissue, and metastatic lymph node in patients with head and neck squamous cell carcinoma (HNSCC) and to evaluate its association with disease stage and smoking. DESIGN: A retrospective study. SETTING: University of Southern California-University Hospital, University of Southern California and Los Angeles County Medical Center, and Department of Otolaryngology-Head and Neck Surgery, University of Southern California, Los Angeles. PATIENTS: Forty-eight patients with different stages of HNSCC (I-IV) were enrolled into this study. Staging was based on the staging system of the American Joint Committee on Cancer. MAIN OUTCOME MEASURES: EphB4 expression in tumor tissue, surrounding normal tissue, and metastatic lymph node was evaluated by immunohistochemical analysis, Western blot, and real-time polymerase chain reaction. EphB4 expression was then compared between patients based on disease stage and smoking status. RESULTS: EphB4 expression was detected in all tumor specimens and metastatic lymph nodes of patients with HNSCC, but expression levels were higher in the metastatic lymph nodes. There was a statistically significantly higher mean EphB4 protein expression and EphB4 gene amplification in patients with advanced disease (stage III or IV) vs patients with initial disease (stage I or II) and in smokers vs nonsmokers. CONCLUSIONS: Overexpression of EphB4 is associated with advanced stages of HNSCC as well as with patients who smoke. These data are the first to demonstrate the association of EphB4 with advanced stages of disease and smoking in HNSCC and hence provide a strong rationale for targeting EphB4 for HNSCC therapies.

Adult↗

PubMed2006

Expression and significance of vascular endothelial growth factor receptor 2 in bladder cancer.

PURPOSE: Vascular endothelial growth factor has a critical role in maintaining tumor microvasculature and, as such, is an attractive target for anti-angiogenic therapy. Aberrant expression of VEGF receptors, especially VEGFR2, on epithelial tumor cells allows VEGF to stimulate growth and migration of tumor cells in an autocrine and/or paracrine manner. Therefore, we studied the expression of VEGF and VEGFR2 in bladder cancer, and the relationship to disease characteristics. MATERIALS AND METHODS: Expression of VEGF and VEGFR2 was studied in a cohort of 72 patients with transitional cell cancer of the bladder. Tumor tissues from all patients were analyzed by immunohistochemistry and examined by a pathologist blinded to patient outcome. Patient demographics and disease outcome were correlated with expression of these markers. Bladder cancer cell lines that express VEGFR2 were studied in vitro and in vivo to establish the significance of VEGF/VEGFR2 signaling. RESULTS: Expression of VEGF and VEGFR2 was observed in 58% and 50% of urothelial tumor cells, respectively. VEGF expression failed to correlate with clinical variables. However, VEGFR2 expression correlated with disease stage (coefficient 0.23, p = 0.05). In addition, VEGFR2 expression increased with tumor invasion into the muscle (p <0.01). Experiments with VEGFR2 positive bladder cancer cell lines in vitro demonstrated increased invasion in response to VEGF. In addition, VEGF inhibition augmented the effect of docetaxel in a murine xenograft model of bladder cancer with a significant inhibition in proliferative index and microvascular density, and induction of apoptosis. CONCLUSIONS: Increased VEGFR2 expression correlates with several features that predict progression of urothelial cancer, including disease stage and invasive phenotype. VEGF targeted therapy may enhance the efficacy of standard therapy for bladder cancer.

Adult↗

PubMed2006

Receptor tyrosine kinase EphB4 is a survival factor in breast cancer.

EphB4, a member of the largest family of receptor tyrosine kinases, is normally expressed on endothelial and neuronal cells. Although aberrant expression of EphB4 has been reported in several human tumors, including breast cancer, its functional significance is not understood. We report here that EphB4 is expressed in 7 of 12 (58%) human breast cancer specimens and 4 of 4 (100%) breast tumor cell lines examined. Overexpression of EphB4 in breast cancer cells was driven by gene amplification and by the erbB family of receptors via activation of Janus tyrosine kinase-signal transducers and activators of transcription and protein kinase B. The aberrantly expressed receptor was phosphorylated by its natural ligand, EphrinB2, and signaled via the protein kinase B pathway. Targeted knockdown of EphB4 expression by small interference RNA (and antisense oligodeoxynucleotides (ODNs)) led to dose-dependent reduction in cell survival, increased apoptosis, and sensitization to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). Antisense ODN-mediated EphB4 knockdown resulted in reduced tumor growth in a murine tumor xenograft model. Antisense ODN-treated tumors were 72% smaller than control tumors at 6 weeks, with an 86% reduction in proliferating cells, 15-fold increase in apoptosis, and 44% reduction in tumor microvasculature. Our data indicate that biologically active EphB4 functions as a survival factor in breast cancer and is a novel target for therapy.

Animals↗

PubMed2005

The soluble extracellular domain of EphB4 (sEphB4) antagonizes EphB4-EphrinB2 interaction, modulates angiogenesis, and inhibits tumor growth.

The receptor tyrosine kinase EphB4 and its ligand EphrinB2 play a crucial role in vascular development during embryogenesis. The soluble monomeric derivative of the extracellular domain of EphB4 (sEphB4) was designed as an antagonist of EphB4/EphrinB2 signaling. sEphB4 blocks activation of EphB4 and EphrinB2; suppresses endothelial cell migration, adhesion, and tube formation in vitro; and inhibits the angiogenic effects of various growth factors (VEGF and bFGF) in vivo. sEphB4 also inhibits tumor growth in murine tumor xenograft models. sEphB4 is thus a therapeutic candidate for vascular proliferative diseases and cancer.

Angiogenesis Inhibitors↗

PubMed2005

Up-regulation of EphB4 in mesothelioma and its biological significance.

PURPOSE: Mesothelioma is a rare malignancy that is incurable and carries a short survival despite surgery, radiation, or chemotherapy. This study was designed to identify novel targets for diagnostic, prognostic, and therapeutic approaches. EXPERIMENTAL DESIGN: The expression and functional significance of the receptor tyrosine kinase EphB4 was studied in vitro and in a murine model of mesothelioma. RESULTS: EphB4 was highly expressed in mesothelioma cell lines and primary tumor tissues but not in normal mesothelium. Knockdown of EphB4 using small interfering RNA and antisense oligodeoxynucleotide showed reduction in cell survival, migration, and invasion. EphB4 knockdown initiated a caspase-8-mediated apoptosis and down-regulation of the anti-apoptotic protein bcl-xl. EphB4 knockdown also resulted in reduced phosphorylation of Akt and down-regulation of matrix metalloproteinase-2 transcription. In addition, murine tumor xenograft studies using EphB4 oligodeoxynucleotides showed a marked reduction in tumor growth accompanied by a specific decline in EphB4 protein levels, reduced cell division, apoptosis in tumor tissue, and decreased microvascular density. CONCLUSIONS: EphB4 is expressed in mesothelioma, provides a survival advantage to tumor cells, and is therefore a potential novel therapeutic target.

Animals↗

PubMed2005

EphB4 expression and biological significance in prostate cancer.

Prostate cancer is the most common cancer in men. Advanced prostate cancer spreading beyond the gland is incurable. Identifying factors that regulate the spread of tumor into the regional nodes and distant sites would guide the development of novel diagnostic, prognostic, and therapeutic targets. The aim of our study was to examine the expression and biological role of EphB4 in prostate cancer. EphB4 mRNA is expressed in 64 of 72 (89%) prostate tumor tissues assessed. EphB4 protein expression is found in the majority (41 of 62, 66%) of tumors, and 3 of 20 (15%) normal prostate tissues. Little or no expression was observed in benign prostate epithelial cell line, but EphB4 was expressed in all prostate cancer cell lines to varying degrees. EphB4 protein levels are high in the PC3 prostate cancer cell line and several folds higher in a metastatic clone of PC3 (PC3M) where overexpression was accompanied by EphB4 gene amplification. EphB4 expression is induced by loss of PTEN, p53, and induced by epidermal growth factor/epidermal growth factor receptor and insulin-like growth factor-I/insulin-like growth factor-IR. Knockdown of the EphB4 protein using EphB4 short interfering RNA or antisense oligodeoxynucleotide significantly inhibits cell growth/viability, migration, and invasion, and induces apoptosis in prostate cancer cell lines. Antisense oligodeoxynucleotide targeting EphB4 in vivo showed antitumor activity in murine human tumor xenograft model. These data show a role for EphB4 in prostate cancer and provide a rationale to study EphB4 for diagnostic, prognostic, and therapeutic applications.

Animals↗

PubMed2005

VEGF antisense therapy inhibits tumor growth and improves survival in experimental pancreatic cancer.

BACKGROUND: Vascular endothelial growth factor (VEGF), a key mediator of angiogenesis, is overexpressed in pancreatic cancer. This study evaluated VEGF production in pancreatic cancer cells and the effect of VEGF antisense on growth and angiogenesis of human pancreatic cancer in a nude mouse model. METHODS: In vitro: VEGF in cell culture supernatant of pancreatic cancer cells (AsPC-1, poorly differentiated; HPAF-2, moderately differentiated) was assessed by enzyme-linked immunosorbent assay. In vivo: A VEGF antisense oligonucleotide (AS-3) was synthesized. One-mm(3) fragments of subcutaneous pancreatic cancer donor tumors were implanted into the pancreas of nude mice also receiving AS-3 (10 mg/kg/day) or vehicle intraperitoneally for 14 weeks. Primary tumor volume, metastasis, and VEGF in plasma and ascites were determined at autopsy. Microvessel density was analyzed in CD31-stained tumors. RESULTS: In vitro: Both pancreatic cancer cell lines secreted VEGF protein (AsPC-1, 4200 +/- 40 pg/10(6) cells; HPAF-2, 8120 +/- 60 pg/10(6) cells). In vivo: AS-3 reduced tumor volume in the HPAF-2 group (860 +/- 140 vs 3830 +/- 590 mm(3)) and metastatic spread in both groups (AsPC-1, 6.5 +/- 0.8 vs 16.7 +/- 0.9 points; HPAF-2, 2.5 +/- 0.2 vs 8.3 +/- 1.5 points). Tumor volume was not different in the AsPC-1 group (1050 +/- 80 vs 1400 +/- 150 mm(3)). Survival was increased in the AsPC-1 group. Plasma levels of VEGF and microvessel density in tumors were significantly reduced in treated animals. Only control animals (50%) developed ascites with high VEGF concentrations. CONCLUSIONS: Human pancreatic cancer cells secrete VEGF at biologically relevant high levels. AS-3 therapy normalizes plasma VEGF and decreases neoangiogenesis, thereby reducing tumor growth and metastasis and improving survival. AS-3-treated animals developed no ascites, suggesting decreased vascular permeability by reducing VEGF expression in pancreatic cancer cells.

Animals↗

PubMed2005

Soluble EphB4 regulates choroidal endothelial cell function and inhibits laser-induced choroidal neovascularization.

PURPOSE: The purpose of this study was to evaluate the effect of a soluble monomeric form of the EphB4 extracellular domain (sEphB4) on choroidal endothelial cell (CEC) migration and tube formation and on experimental laser-induced choroidal neovascularization (CNV). METHODS: EphrinB2 and EphB4 expression in CECs was investigated by Western blot analysis and immunohistochemistry. Effects of sEphB4 (0.5-3 microg/mL) on CEC migration were evaluated with a modified Boyden chamber assay. Tube formation was assayed in CEC cultures in collagen gel. CNV was induced in rats by laser photocoagulation. The effects of intravitreal injection of sEphB4 on CNV development were evaluated at day 14 by fluorescein angiography (FA), confocal volumetric analysis of isolectin-B4 labeled flatmounts, and histologic examination of CNV membranes. RESULTS: CEC cells express both EphB4 and EphrinB2, according to Western blot analysis. Immunohistochemical sections of rat eye showed immunoreactivity for both EphB4 and EphrinB2 in the choroidal endothelium. sEphB4 reduced CEC migration in response to vascular endothelial growth factor (P < 0.01). Similarly, sEphB4 inhibited CEC tube formation in a dose-dependent manner. EphB4, and to a lesser extent EphrinB2, were detected on vascular channels within laser-induced CNV membranes. Intravitreal injection of sEphB4 inhibited laser-induced CNV formation. CNV membranes showed a reduction in leakage score (P < 0.05), and membrane volumes were reduced in size (P < 0.05). Histologic analysis revealed that vascularity was reduced in sEphB4-treated membranes. CONCLUSIONS: Recombinant soluble monomeric EphB4 exerts an inhibitory effect on choroidal angiogenesis in vitro and in vivo. It should be further evaluated for its potential as a novel therapy for CNV.

Animals↗

PubMed2004

Ephrin B2 expression in Kaposi sarcoma is induced by human herpesvirus type 8: phenotype switch from venous to arterial endothelium.

Kaposi sarcoma (KS) is an angioproliferative tumor derived from endothelial cells in which tumor cells form aberrant vascular structures. Ephrin B2 and ephrin B4 (EphB4) are artery- and vein-specific proteins, respectively, with critical roles in vessel maturation. We investigated whether the disorganized KS vasculature was due to unbalanced expression of ephrin B2 and EphB4. Secondly, we wished to determine if human herpesvirus type 8 (HHV-8), the viral agent associated with KS, regulates ephrin B2 and EphB4. An arterial phenotype was observed in KS tissue and cell lines, as shown by abundant expression of ephrin B2 with little or no EphB4. Infection of venous endothelial cells with HHV-8 resulted in a phenotype switch from EphB4 to ephrin B2, similar to that seen with vascular endothelial growth factor (VEGF). The HHV-8 effect on ephrin B2 expression was reproduced with the HHV-8-specific viral G-protein-coupled receptor. We also showed that ephrin B2 expression is required for KS cell viability by knock down with siRNA. KS is the first example of a human tumor with a predominantly arterial phenotype. This predominance can be attributed to expression of HHV-8 proteins and their downstream effects. Ephrin B2 is thus an important novel factor in KS biology and a potential target for therapy.

Arteries↗

PubMed2004

Th1 and Th2 cytokines and IgE levels in identical twins with varying levels of cigarette consumption.

Some have suggested that tobacco smoke may skew the immune system toward a Th2 pattern, however the effects of genetics or childhood exposures could explain these results. We compared PMBC supernatant or serum Th1 (INF-gamma) and Th2 (IL-4, IL-5, and IL-13) cytokine and IgE levels in members of 45 pairs of nonasthmatic monozygotic twins with varying levels of current cigarette consumption to determine if smoking was associated with Th1/Th2 function after accounting for genetic factors. A statistically significant dose-response was observed between levels of smoking and IL-13 (p=0.05). Mean IL-13 level among heavy smokers (20+ cigarettes/day) was 146% higher than that among nonsmokers (+26.2 pg/mL; p=0.04). The mean IL-5 level among heavy smokers was 166% higher than that among light (<20 cigarettes/day) smokers (+3.4 pg/mL; p=0.03). No statistically significant differences in INF-gamma, IL-4, or IgE levels were observed. Smoking appears to be associated with increased levels of IL-13.

Cytokines↗

PubMed2004

VEGF and myeloid leukemias.

Vascular endothelial growth factor and vascular endothelial growth factor receptors participate in the growth and survival of myeloid leukemic progenitors. With the development of multiple anti-angiogenic agents, there is potential that some of these novel agents will have anti-leukemic activity. Since these agents work by mechanisms distinct from current cytotoxic chemotherapies, they may be useful both in chemoresistant leukemia patients and in combinations to improve remission rates and remission durations.

Angiogenesis Inhibitors↗

PubMed2003

IL-6 levels and genotype are associated with risk of young adult Hodgkin lymphoma.

Identical twins of young adult Hodgkin lymphoma case subjects are much more likely to develop the disease compared with fraternal twins of case subjects, suggesting a genetic determinant. Interleukin 6 (IL-6) levels are increased in patients with Hodgkin lymphoma and are correlated with a poor prognosis. We hypothesized that a heritable abnormality in IL-6 regulation may predispose to young adult Hodgkin lymphoma. We obtained blood specimens from 88 young adult Hodgkin lymphoma case subjects and their twins as well as from 87 matched control subjects. IL-6 was measured from unstimulated peripheral blood mononuclear cell (PBMC) supernatant with enzyme-linked immunosorbent assays (ELISAs) and compared by using analysis of covariance. Unaffected identical twins of case subjects (surrogate case subjects) had a 87.8% higher IL-6 level compared with matched control subjects (mean difference, +483.7 pg/mL, P =.04). Analysis of the IL-6 174G>C promoter polymorphism genotypes showed that risk decreased with an increasing number of C alleles (P =.01). The CC (low secreting) genotype was associated with a decreased risk of young adult Hodgkin lymphoma relative to the GG (high secreting) genotype (odds ratio [OR] =.29; P =.03). Risk was decreased for both nodular sclerosis and other subtypes. Persons with genetically determined lower IL-6 levels may be less susceptible to young adult Hodgkin lymphoma.

Adolescent↗

PubMed2003

Natural killer cell cytolytic activity is necessary for in vivo antitumor activity of the dipeptide L-glutamyl-L-tryptophan.

A dipeptide, L-glutamyl L-tryptophan (L-glu-L-trp), was identified in a screen for immunomodulators in the soluble fraction of the thymus. L-glu-L-trp inhibits tumor growth in mice without showing direct cellular toxicity in a variety of human tumor cell lines. L-glu-L-trp antitumor activity in vivo requires the presence of natural killer (NK) cells. Defective trafficking of cytoplasmic granules caused by the Lyst mutation also resulted in loss of antitumor activity of the dipeptide. The effect of L-glu-L-trp on tumor growth in mice with targeted gene mutations demonstrated the absolute requirement for perforin for antitumor activity. The requirement of 2 major modulators of NK cell activity, gamma interferon (IFNgamma) and interleukin (IL)-12, were also tested. L-glu-L-trp had full antitumor activity in IFNgamma knockout mice, but had significantly diminished activity in IL-12 knockout mice. These data show that L-glu-L-trp antitumor activity in mice is dependent on cytolytic cell activity of NK or NKT cells. L-glu-L-trp in vivo regulates NK cell function independent of IFNgamma but partly dependent on IL-12.

Angiogenesis Inhibitors↗

PubMed2003

Malignant mesothelioma growth inhibition by agents that target the VEGF and VEGF-C autocrine loops.

Malignant mesothelioma (MM) is a locally aggressive tumor that originates from the mesothelial cells of the pleural and sometimes peritoneal surface. Conventional treatments for MM, consisting of chemotherapy or surgery give little survival benefit to patients, who generally die within 1 year of diagnosis. Hence, there is an urgent need for the development of alternative therapies. Vascular endothelial growth factor (VEGF) is an autocrine growth factor for MM. The closely related molecule, VEGF-C, is also implicated in malignant mesothelioma growth. VEGF-C and its cognate receptor VEGFR-3 are co-expressed in mesothelioma cell lines. A functional VEGF-C autocrine growth loop was demonstrated in mesothelioma cells by targeting VEGF-C expression and binding to VEGFR-3. The ability of novel agents that reduce the levels of VEGF and VEGF-C to inhibit mesothelioma cell growth in vitro was assessed. Antisense oligonucleotide (ODN) complementary to VEGF that inhibited VEGF and VEGF-C expression simultaneously specifically inhibited mesothelioma cell growth. Similarly, antibodies to VEGF receptor (VEGFR-2) and VEGF-C receptor (VEGFR-3) were synergistic in inhibiting mesothelioma cell growth. In addition, a diphtheria toxin-VEGF fusion protein (DT-VEGF), which is toxic to cells that express VEGF receptors was very effective in inhibiting mesothelioma cell growth in vitro. These results indicate that targeting VEGF and VEGF-C simultaneously may be an effective therapeutic approach for malignant mesothelioma.

Antibodies↗

PubMed2003

Expression of EphB4 in head and neck squamous cell carcinoma.

EphB4 is a receptor tyrosine kinase that is expressed on epithelial cells during fetal life. It is also expressed on some venous endothelial cells. We conducted a study of six men with primary squamous cell carcinoma of the head and neck (HNSCC) that had metastasized to the cervical lymph nodes. Our goal was to determine if EphB4 is aberrantly expressed in cases of HNSCC and to determine if there is a qualitative difference between the expression of EphB4 on primary and metastatic tumors and its expression on normal mucosa adjacent to primary tumors. From each patient, we obtained specimens of the primary tumor, the nodal metastasis, and the adjacent normal mucosa, and we performed immunocytochemistry on each. We observed EphB4 expression in all primary and metastatic tumors and no expression in the normal tissue. In each of the six patients, expression was greater in the metastatic tumor than in the primary tumor. We conclude that EphB4 is a novel target in the treatment of HNSCC.

Adult↗

PubMed2002

A multicenter phase II study of the intravenous administration of liposomal tretinoin in patients with acquired immunodeficiency syndrome-associated Kaposi's sarcoma.

BACKGROUND: A multicenter trial was conducted to determine the efficacy and toxicity of escalating dosages of liposomal tretinoin (all-trans-retinoic acid) administered once or three times weekly in patients with acquired immunodeficiency syndrome (AIDS)-associated Kaposi sarcoma. METHODS: Seventy-six patients with acquired immunodeficiency syndrome (AIDS)-associated Kaposi sarcoma were randomized to receive the study drug either once (n = 30) or 3 times weekly (n = 46). The starting dosage was 60 mg/m(2), which was escalated to 90 mg/m(2) and then 120 mg/m(2) if the drug was well tolerated (<or= Grade 2 toxicities [according to the Southwest Oncology Group toxicity scale]). Four weeks of therapy constituted 1 cycle; patients could receive up to 8 cycles and those who completed 8 cycles were given the option of receiving extended therapy. Clinical response was defined as complete response (CR), partial response (PR), or stable disease (SD). RESULTS: Efficacy was assessed after the completion of 3 treatment cycles; 28.9% of patients (22 of 76 patients) responded (no CRs, 1 PR, and 21 SDs). Among the patients receiving treatment 3 times weekly, 16 of 49 patients (32.7%) achieved a clinical response at the end of the third treatment cycle (no CRs, 1 PR, and 15 SDs). Concomitant or prior use of protease inhibitors did not appear to affect the patient's response to treatment (P = 0.183). CONCLUSIONS: Liposomal tretinoin is a new therapeutic agent that has been reported to have some clinical activity in patients with AIDS-associated Kaposi sarcoma. A three-times-per-week dosing schedule was noted to be more effective compared with a once-a-week schedule without any significant difference in toxicity reported.

Acquired Immunodeficiency Syndrome↗