Safety and antitumor activity of the anti-PD-1 antibody pembrolizumab in patients with recurrent carcinoma of the anal canal.

Background: Safety and efficacy of pembrolizumab, a humanized programmed death 1 monoclonal antibody, was assessed in KEYNOTE-028, a multicohort, phase Ib trial for patients with programmed death ligand 1 (PD-L1)-positive advanced solid tumors. We report results for the cohort of patients with advanced anal carcinoma. Patients and methods: Patients with PD-L1-positive tumors (≥1%) received intravenous pembrolizumab 10 mg/kg once every 2 weeks for up to 2 years or until confirmed progression or unacceptable toxicity. Response was assessed every 8 weeks for the first 6 months and every 12 weeks thereafter per Response Evaluation Criteria In Solid Tumors, version 1.1. Primary endpoints were safety and overall response rate per investigator review. Secondary endpoints included progression-free survival, overall survival, and response duration. Data cutoff date was 1 July 2015. Results: Of the 43 patients with advanced anal carcinoma evaluable for PD-L1 expression, 32 (74%) had PD-L1-positive tumors as assessed with the 22C3 prototype assay, of whom 25 were enrolled between April and September 2014. Sixteen patients (64%) experienced treatment-related adverse events; the most common ones were diarrhea and fatigue in four patients (16%) each and nausea in three patients (12%). There were no treatment-related deaths or discontinuations as of the data cutoff date. Among the 24 patients with squamous cell carcinoma histology, four had confirmed partial response, for an overall response rate of 17% [95% confidence interval (CI), 5%-37%) and 10 (42%) had confirmed stable disease, for a disease control rate of 58%. One additional patient with non-squamous histology had confirmed stable disease. Conclusion: In this population of patients with PD-L1-positive advanced squamous cell anal carcinoma, pembrolizumab demonstrated a manageable safety profile and encouraging antitumor activity. These data support further study of pembrolizumab for this patient population. ClinicalTrials.gov: NCT02054806.

Efficacy of the nanoparticle-drug conjugate CRLX101 in combination with bevacizumab in metastatic renal cell carcinoma: results of an investigator-initiated phase I-IIa clinical trial.

BACKGROUND: Anti-angiogenic therapies are effective in metastatic renal cell carcinoma (mRCC), but resistance is inevitable. A dual-inhibition strategy focused on hypoxia-inducible factor (HIF) is hypothesized to be active in this refractory setting. CRLX101 is an investigational camptothecin-containing nanoparticle-drug conjugate (NDC), which durably inhibits HIF1α and HIF2α in preclinical models and in gastric cancer patients. Synergy was observed in the preclinical setting when combining this NDC and anti-angiogenic agents, including bevacizumab. PATIENTS AND METHODS: Patients with refractory mRCC were treated every 2 weeks with bevacizumab (10 mg/kg) and escalating doses of CRLX101 (12, 15 mg/m(2)) in a 3 + 3 phase I design. An expansion cohort of 10 patients was treated at the recommended phase II dose (RP2D). Patients were treated until progressive disease or prohibitive toxicity. Adverse events (AEs) were assessed using CTCAE v4.0 and clinical outcome using RECIST v1.1. RESULTS: Twenty-two patients were response-evaluable in an investigator-initiated trial at two academic medical centers. RCC histologies included clear cell (n = 12), papillary (n = 5), chromophobe (n = 2), and unclassified (n = 3). Patients received a median of two prior therapies, with at least one prior vascular endothelial tyrosine kinase inhibitor therapy (VEGF-TKI). No dose-limiting toxicities were observed. Grade ≥3 AEs related to CRLX101 included non-infectious cystitis (5 events), fatigue (3 events), anemia (2 events), diarrhea (2 events), dizziness (2 events), and 7 other individual events. Five of 22 patients (23%) achieved partial responses, including 3 of 12 patients with clear cell histology and 2 of 10 patients (20%) with non-clear cell histology. Twelve of 22 patients (55%) achieved progression-free survival (PFS) of >4 months. CONCLUSIONS: CRLX101 combined with bevacizumab is safe in mRCC. This combination fulfilled the protocol's predefined threshold for further examination with responses and prolonged PFS in a heavily pretreated population. A randomized phase II clinical trial in mRCC of this combination is ongoing.

A randomized, phase II trial of cetuximab with or without PX-866, an irreversible oral phosphatidylinositol 3-kinase inhibitor, in patients with relapsed or metastatic head and neck squamous cell cancer.

BACKGROUND: The phosphotidylinositol-3 kinase (PI3K)/serine-threonine kinase/mammalian target of rapamycin signaling pathway is frequently altered in head and neck squamous cell cancer (HNSCC). PX-866 is an oral, irreversible, pan-isoform inhibitor of PI3K. A phase I trial demonstrated tolerability of this combination. This randomized phase II study evaluated PX-866 combined with cetuximab in patients with advanced, refractory HNSCC. METHODS: Patients with recurrent or metastatic HNSCC who had received at least one and no more than two prior systemic treatment regimens were randomized (1 : 1) to cetuximab with or without PX-866 (8 mg p.o. daily; arms A and B, respectively). The primary end point was progression-free survival (PFS). Secondary end points included objective response rate (ORR), overall survival (OS), toxicity, and correlation of key biomarkers with efficacy outcomes. RESULTS: Eighty-three patients were enrolled. There was a similar response rate between arms (10% versus 7%). Of patients for whom tissue was assessable, 57% were human papillomavirus (HPV) positive. Median PFS was 80 days in both arms and there was no difference in OS between the two arms (211 versus 256 days). Overall toxicity was higher in arm A compared with arm B, especially in terms of nausea (53% versus 23%), vomiting (45% versus 15%), fatigue (43% versus 23%), diarrhea (40% versus 21%), and hypokalemia (25% versus 10%). Grade 3 or higher adverse events were infrequent, but more common in the combination arm although without a specific pattern. PIK3CA mutations were observed in 17% of the cases assessed, and PTEN loss was infrequently observed. CONCLUSION: The addition of PX-866 to cetuximab did not improve PFS, RR, or OS in patients with advanced, refractory HNSCC enrolled without molecular preselection. In this contemporary cohort, HPV-positive patients comprised the majority, and neither HPV-positive nor HPV-negative patients derived clinical benefit for the addition of cetuximab plus PX-866.

Phase I study of every 2- or 3-week dosing of ramucirumab, a human immunoglobulin G1 monoclonal antibody targeting the vascular endothelial growth factor receptor-2 in patients with advanced solid tumors.

BACKGROUND: Ramucirumab is a fully human immunoglobulin G1 monoclonal antibody receptor antagonist designed to block the ligand-binding site of vascular endothelial growth factor receptor-2 (VEGFR-2). An initial phase I study evaluated ramucirumab administered weekly in advanced cancer patients. This phase I study of ramucirumab [administered every 2 or 3 weeks (Q2W or Q3W)] examined safety, maximum tolerated dose, pharmacokinetics, immunogenicity, antitumor activity, and pharmacodynamics. PATIENTS AND METHODS: Patients with advanced solid malignancies were treated with escalating doses of ramucirumab i.v. over 1 h. Blood was sampled for pharmacokinetics studies throughout treatment; levels of circulating vascular endothelial growth factor-A (VEGF-A) and soluble VEGF receptors (R)-1 and -2 were assessed. RESULTS: Twenty-five patients were treated with ramucirumab: 13 with 6, 8, or 10 mg/kg Q2W, and 12 with 15 or 20 mg/kg Q3W. The median treatment duration was 12 weeks (range 2-81). No dose-limiting toxicities were observed. The most frequently reported adverse events (AEs) included proteinuria and hypertension (n = 6 each), and diarrhea, fatigue and headache (n = 4 each). Treatment-related grade 3/4 AEs were: two grade 3 hypertension (10 and 20 mg/kg), one each grade 3 vomiting, fatigue (20 mg/kg), atrial flutter (15 mg/kg), and one each grade 4 duodenal ulcer hemorrhage (6 mg/kg) and grade 4 pneumothorax (20 mg/kg). Pharmacokinetic analysis revealed low clearance and half-life of ∼110-160 h. Analysis of serum biomarkers indicated considerable patient-to-patient variability, but trends toward elevated VEGF-A and a transient decline in soluble VEGFR-2. Fifteen patients (60%) had best response of stable disease, with a median duration of 13 months (range 2-18 months) in tumor types including colorectal, renal, liver, and neuroendocrine cancers. CONCLUSION: Ramucirumab was well tolerated. Study results led to recommended phase II doses of 8 mg/kg Q2W and 10 mg/kg Q3W. Prolonged stable disease was observed, suggesting ramucirumab efficacy in various solid tumors. CLINICALTRIALSGOV: NCT00786383.

Phase I trial of axitinib combined with platinum doublets in patients with advanced non-small cell lung cancer and other solid tumours.

BACKGROUND: This phase I dose-finding trial evaluated safety, efficacy and pharmacokinetics of axitinib, a potent and selective second-generation inhibitor of vascular endothelial growth factor receptors, combined with platinum doublets in patients with advanced non-small cell lung cancer (NSCLC) and other solid tumours. METHODS: In all, 49 patients received axitinib 5 mg twice daily (b.i.d.) with paclitaxel/carboplatin or gemcitabine/cisplatin in 3-week cycles. Following determination of the maximum tolerated dose, a squamous cell NSCLC expansion cohort was enroled and received axitinib 5 mg b.i.d. with paclitaxel/carboplatin. RESULTS: Two patients experienced dose-limiting toxicities: febrile neutropenia (n=1) in the paclitaxel/carboplatin cohort and fatigue (n=1) in the gemcitabine/cisplatin cohort. Common nonhaematologic treatment-related adverse events were hypertension (36.7%), diarrhoea (34.7%) and fatigue (28.6%). No grade ≥3 haemoptysis occurred among 12 patients with squamous cell NSCLC. The objective response rate was 37.0% for patients receiving axitinib/paclitaxel/carboplatin (n=27) and 23.8% for patients receiving axitinib/gemcitabine/cisplatin (n=21). Pharmacokinetics of axitinib and chemotherapeutic agents were similar when administered alone or in combination. CONCLUSION: Axitinib 5 mg b.i.d. may be combined with standard paclitaxel/carboplatin or gemcitabine/cisplatin regimens without evidence of overt drug-drug interactions. Both combinations demonstrated clinical efficacy and were well tolerated.

Phase I study of axitinib combined with paclitaxel, docetaxel or capecitabine in patients with advanced solid tumours.

BACKGROUND: Axitinib, a potent and selective second-generation inhibitor of vascular endothelial growth factor receptors, enhanced the efficacy of chemotherapy in human xenograft tumour models. This phase I study investigated the safety, tolerability, pharmacokinetics and antitumour activity of axitinib combined with chemotherapy. METHODS: A total of 42 patients with advanced solid tumours received a continuous axitinib starting dose of 5 mg twice daily (b.i.d.) plus paclitaxel (90 mg m(-2) weekly), docetaxel (100 mg m(-2) every 3 weeks) or capecitabine (1000 or 1250 mg m(-2) b.i.d., days 1-14). RESULTS: Common treatment-related adverse events across all cohorts were nausea (45.2%), hypertension (45.2%), fatigue (42.9%), diarrhoea (38.1%), decreased appetite (33.3%) and hand-foot syndrome (31.0%). There was one complete response, nine partial responses and seven patients with stable disease. Ten patients (23.8%) remained on therapy for >8 months. Paclitaxel and capecitabine pharmacokinetics were similar in the absence or presence of axitinib, but docetaxel exposure was increased in the presence of axitinib. Axitinib pharmacokinetics were similar in the absence or presence of co-administered agents. CONCLUSIONS: Axitinib combined with paclitaxel or capecitabine was well tolerated; no additive increase in toxicities was observed. Antitumour activity was observed for each treatment regimen and across multiple tumour types.

Sequential therapy for the locally advanced larynx and hypopharynx cancer subgroup in TAX 324: survival, surgery, and organ preservation.

BACKGROUND: Locally advanced laryngeal and hypopharyngeal cancers (LHC) represent a group of cancers for which surgery, laryngectomy-free survival (LFS), overall survival (OS), and progression-free survival (PFS) are clinically meaningful end points. PATIENTS AND METHODS: These outcomes were analyzed in the subgroup of assessable LHC patients enrolled in TAX 324, a phase III trial of sequential therapy comparing docetaxel plus cisplatin and fluorouracil (TPF) against cisplatin and fluorouracil (PF), followed by chemoradiotherapy. RESULTS: Among 501 patients enrolled in TAX 324, 166 had LHC (TPF, n = 90; PF, n = 76). Patient characteristics were similar between subgroups. Median OS for TPF was 59 months [95% confidence interval (CI): 31-not reached] versus 24 months (95% CI: 13-42) for PF [hazard ratio (HR) for death: 0.62; 95% CI: 0.41-0.94; P = 0.024]. Median PFS for TPF was 21 months (95% CI: 12-59) versus 11 months (95% CI: 8-14) for PF (HR: 0.66; 95% CI: 0.45-0.97; P = 0.032). Among operable patients (TPF, n = 67; PF, n = 56), LFS was significantly greater with TPF (HR: 0.59; 95% CI: 0.37-0.95; P = 0.030). Three-year LFS with TPF was 52% versus 32% for PF. Fewer TPF patients had surgery (22% versus 42%; P = 0.030). CONCLUSIONS: In locally advanced LHC, sequential therapy with induction TPF significantly improved survival and PFS versus PF. Among operable patients, TPF also significantly improved LFS and PFS. These results support the use of sequential TPF followed by carboplatin chemoradiotherapy as a treatment option for organ preservation or to improve survival in locally advanced LHC.

Bioequivalence study of a new oral topotecan formulation, relative to the current topotecan formulation, in patients with advanced solid tumors.

OBJECTIVE: The aims of this study were to investigate the bioequivalence of a new oral topotecan formulation (i.e., proposed commercial formulation) relative to the current oral formulation (formulation used in previous clinical trials), the effect of food on the absorption and disposition of the new oral topotecan and its safety and tolerability in patients with advanced solid tumors. PATIENTS AND METHODS: This was a multi-center, pharmacological Phase I, multiple-dose, randomized, open-label, cross-over bioequivalence study. In the bioequivalence part, 85 patients were randomized to receive either a 4 mg (4 x 1 mg) dose of the new or current formulation on Days 1 or 8. In the food-effect part, 23 patients received a 4 mg (4 x 1 mg) dose of the new formulation in a fasted and fed state. Total topotecan and topotecan lactone were determined and pharmacokinetic data were analyzed by non-compartmental method. RESULTS: Bioequivalence was demonstrated as the 90% confidence intervals of the ratio of the new to current formulation for both the area under the plasma concentration-time curve (AUC) and the maximal drug concentration (Cmax) for topotecan lactone were contained within the 0.8 - 1.25 boundary. The AUC and Cmax were similar in the fed and fasted state whilst food delayed the tmax for topotecan lactone and total topotecan. Safety data were collected on all subjects enrolled (n = 108) and were consistent with observations from previous studies of oral topotecan. All subjects experienced at least one adverse event, the majority of which were graded as mild to moderate in severity. CONCLUSION: The new oral topotecan formulation demonstrated bioequivalence to the current formulation and demonstrated it can be administered to patients with solid tumors in the fed or fasted state with similar systemic exposure.

A phase I study of the safety and pharmacokinetics of trabectedin in combination with pegylated liposomal doxorubicin in patients with advanced malignancies.

BACKGROUND: To determine the maximum tolerated dose (MTD), safety, potential pharmacokinetic (PK) interactions, and effect on liver histology of trabectedin in combination with pegylated liposomal doxorubicin (PLD) for advanced malignancies. PATIENTS AND METHODS: Entry criteria for the 36 patients included normal liver function, prior doxorubicin exposure <250 mg/m(2), and normal cardiac function. A 1-h PLD (30 mg/m(2)) infusion was followed immediately by one of six trabectedin doses (0.4, 0.6, 0.75, 0.9, 1.1, and 1.3 mg/m(2)) infused over 3 h, repeated every 21 days until evidence of complete response (CR), disease progression, or unacceptable toxicity. Plasma samples were obtained to assess PK profiles. RESULTS: The MTD of trabectedin was 1.1 mg/m(2). Drug-related grade 3 and 4 toxic effects were neutropenia (31%) and elevated transaminases (31%). Six patients responded (one CR, five partial responses), with an overall response rate of 16.7%, and 14 had stable disease (less than a 50% reduction and less than a 25% increase in the sum of the products of two perpendicular diameters of all measured lesions and the appearance of no new lesions) >4 months (39%). Neither drug had its PK affected significantly by concomitant administration compared with trabectedin and PLD each given as a single agent. CONCLUSION: Trabectedin combined with PLD is generally well tolerated at therapeutic doses of both drugs in pretreated patients with diverse tumor types and appears to provide clinical benefit. These results support the need for additional studies of this combination in appropriate cancer types.

Partial purification of a nuclear protein that binds to the CCAAT box of the mouse alpha 1-globin gene.

We enriched a fraction from nuclear extracts of murine erythroleukemia cells which contains a protein able to form stable complexes with the promoter region of the alpha 1-globin gene. Binding activity, which is present in mouse brain and a variety of cultured mouse and human cell lines, is not erythroid cell specific. Binding studies with alpha-globin gene promoter deletion mutants as well as DNase I footprinting and dimethyl sulfate protection studies showed that the factor bound specifically to the CCAAT box of the alpha 1 promoter. Enriched factor preparations exhibited weak binding to the promoter region of the beta maj-globin gene. This suggests that this protein could bind differentially to these two promoters in vivo. The enriched factor may be a ubiquitous nuclear protein involved in the differential regulation of the alpha 1- and beta maj-globin genes.

DNA affinity labeling of adenovirus type 2 upstream promoter sequence-binding factors identifies two distinct proteins.

A rapid affinity labeling procedure with enhanced specificity was developed to identify DNA-binding proteins. 32P was first introduced at unique phosphodiester bonds within the DNA recognition sequence. UV light-dependent cross-linking of pyrimidines to amino acid residues in direct contact at the binding site, followed by micrococcal nuclease digestion, resulted in the transfer of 32P to only those specific protein(s) which recognized the binding sequence. This method was applied to the detection and characterization of proteins that bound to the upstream promoter sequence (-50 to -66) of the human adenovirus type 2 major late promoter. We detected two distinct proteins with molecular weights of 45,000 and 116,000 that interacted with this promoter element. The two proteins differed significantly in their chromatographic and cross-linking behaviors.

Regulation of eukaryotic translation initiation factor expression during T-cell activation.

Primary T-cells are metabolically quiescent, with little DNA, RNA or protein synthesis. Upon mitogenic stimulation the rate of protein synthesis increases 10-fold. We have studied the role of eIF-2 and eIF-4 alpha (eIF-4E) expression in the mechanism of translational activation. During this period, the levels of eIF-2 alpha and eIF-4 alpha mRNA increase some 50-fold. Similar to the increase in ribosomes and mRNA, the number of eIF-2 alpha, eIF-2 beta, and eIF-4 alpha molecules per cell also increase 2-3-fold. This suggests that in addition to an increase in the pool size of translational components, an additional mechanism exists which results in an increased efficiency of factor utilization. We have looked at initiation factor phosphorylation. We find that eIF-2 alpha does not undergo significant changes in its phosphorylation state nor is there a change in the efficiency of eIF-2 utilization. However, there is a rapid increase in the phosphorylation state of eIF-4 alpha which correlates with the rapid increase in translational activity. It thus appears there are 2 distinct components responsible for the translational activation of quiescent T-cells during mitogenic stimulation. The first is the phosphorylation of eIF-4 alpha, with a concomitant increase in the efficiency of eIF-4 alpha utilization. The second is an increase in the pool sizes of eIF-2 and eIF-4 alpha.

Clinical-pathologic study of early breast cancer treated by primary radiation therapy.

We performed a clinical-pathologic review of 231 patients with early breast cancer treated by primary radiation therapy. There were 27 patients with infiltrating ductal carcinoma treated with excisional biopsy whose tumors showed a constellation of histologic features: moderate or marked intraductal carcinoma in the tumor, intraductal carcinoma in the adjacent tissue, and high nuclear grade. These patients had a 5-yr local tumor control rate of 61% compared to 96% for similar patients whose tumors did not show all three features. Radiation dose to the primary tumor area influenced the likelihood of local recurrence in these 27 patients: 15 of these patients received 6000 rads or more to the primary tumor area and had a 5-yr local tumor control rate of 84%, compared to 48% for the 12 patients who received less than 6000 rads. These results indicate that a subgroup of breast cancer patients can be identified that has a high risk of local recurrence when an insufficient radiation dose (i.e., less than 6000 rads) is delivered to the primary tumor area.

Phase I/II study of intermittent all-trans-retinoic acid, alone and in combination with interferon alfa-2a, in patients with epidemic Kaposi's sarcoma.

PURPOSE: A phase I/II study of oral all-trans-retinoic acid (ATRA; tretinoin), administered every other week alone and then in combination with interferon (IFN) alfa-2a, was undertaken to evaluate the activity, toxicity, and pharmacokinetics of this regimen in patients with human immunodeficiency virus (HIV)-associated Kaposi's sarcoma (KS). PATIENTS AND METHODS: Thirteen patients with HIV-associated KS, eight of whom had more than 100 CD4 cells/microL, were entered. The protocol initially called for patients to receive 150 mg/m2/d of ATRA every other week. However, this regimen was associated with headaches, and the initial dose of ATRA was reduced to 40 mg/m2/d orally in three divided doses, increasing to a maximum of 100 mg/m2/d. After 12 weeks, IFN alfa-2a could be added. RESULTS: The principal toxicities from ATRA were headaches (12 patients) and dry skin or lip (seven patients). Of 12 assessable patients, 10 had progressive disease and two had stable disease on ATRA alone. One of eight assessable patients who went on to receive ATRA plus IFN alfa-2a had partial response (PR). There were no overall changes in the serum HIV p24 antigen (Ag) level or CD4 count during treatment with ATRA alone. Peak ATRA levels decreased during the week of continuous ATRA therapy, but rebounded when treatment was resumed after a week without the drug. CONCLUSION: Intermittent ATRA therapy was reasonably well tolerated and provided a means to circumvent the low plasma exposure found with continuous ATRA therapy. However, we were unable to document antitumor activity in patients with HIV-associated KS.

Nucleosome disruption precedes transcription and is largely limited to the transcribed domain of globin genes in murine erythroleukemia cells.

We used micrococcal nuclease to separate murine erythroleukemia cell (MELC) chromatin into soluble and insoluble fractions which differ in gene content and chromatin structure. Genes that are not expressed in the erythroid lineage, such as the Ig alpha and albumin genes, distribute preferentially into the soluble rather than the insoluble fraction, and are organized into nucleosomes in both fractions. Both alpha 1- and beta maj-globin genes are enriched in the insoluble fraction and are organized into structures that are partially devoid of nucleosomes in uninduced MELC, when the genes are transcriptionally inactive. Following chemical induction of MELC and the onset of globin gene transcription, globin gene enrichment and nucleosome disruption in the insoluble chromatin fraction increase. Using seven DNA subclones that span the beta maj-globin gene we show that insolubility and nucleosome disruption are largely limited to DNA sequences lying within the transcribed domain. Non-transcribed, flanking sequences are soluble and organized into nucleosomes. In addition, the globin genes found in insoluble, non-nucleosomal chromatin contain previously engaged RNA polymerases which can elongate globin RNA chains in vitro in a pattern qualitatively and quantitatively similar to intact nuclei. These results are discussed in terms of a model for globin gene activation during erythropoeisis.

Concanavalin A-induced granulocyte-macrophage colony-stimulating factor production in a murine T-cell line is posttranscriptionally controlled.

Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a hematopoietic growth factor (HGF) that regulates the proliferation and differentiation of cells of the myeloid lineage. It can be produced by a variety of cells. One of the major sources of GM-CSF is activated T cells, which transiently produce this HGF. We used the EL-4 thymoma cell line as a model system to address the molecular basis for GM-CSF regulation in T cells. Both concanavalin A (ConA) and the phorbol ester, 12-O-tetradecanoylphorbol 13-acetate (TPA) induce GM-CSF expression in EL-4 cells. However, the biological activity of GM-CSF in the supernatants of the TPA-stimulated cells was higher than that of ConA-stimulated cells. To elucidate this difference in biological activity levels, we examined how ConA regulates GM-CSF gene expression in EL-4 cells and compared it to the better-characterized regulation by TPA. Peak mRNA levels of GM-CSF occur 6 h after stimulation with either of these two agents. GM-CSF mRNA levels after ConA treatment are lower and decrease significantly after 10 h compared to TPA treatment, which causes much higher levels that persist for at least 24 h. Neither agent alters GM-CSF gene transcription. Actinomycin D chase experiments show that ConA increases the GM-CSF mRNA half-life from less than 30 to 90 min, whereas TPA prolongs it to greater than 3 h. These results indicate that GM-CSF mRNA induction by ConA (in common with TPA) is regulated predominantly via RNA stabilization and that the difference in prolongation of the mRNA half-life provides the primary explanation for the lower levels of GM-CSF mRNA induced by ConA compared to TPA.

HIV-specific immunity following immunization with HIV synthetic envelope peptides in asymptomatic HIV-infected patients.

OBJECTIVE: A phase I trial was conducted to evaluate the safety and immunogenicity of an HIV synthetic peptide vaccine in HIV-seropositive individuals. The immunogens used in this study were PCLUS 3-18MN and PCLUS 6.1-18MN envelope peptides. METHODS: Eight HIV-infected patients received six subcutaneous injections of 160 microg PCLUS 3-18MN in Montanide ISA 51 and were followed longitudinally for a year after the first immunization. Peripheral blood mononuclear cells (PBMC) were tested for peptide-specific T helper and cytotoxic T cell (CTL) responses, HIV-1MN neutralizing antibodies and antibodies against HIV PCLUS 3 and P18 MN peptides. RESULTS: PCLUS 3-1 8MN-specific T helper responses were significantly increased at 36 weeks (P < 0.05, after adjustment for multiple comparisons) following initial immunization with PCLUS 3-18MN. A P18MN-specific CTL response, not present prior to vaccination, was observed after immunization in one patient. Serum HIV-1 MN-neutralizing antibody titers increased in each of the three patients who had low titers prior to immunization. Plasma HIV RNA levels and CD4 cell counts did not change appreciably during the study period. CONCLUSIONS: This trial demonstrates that both peptides can be safely administered to HIV-infected individuals and that PCLUS 3-18MN induces increases in HIV peptide-specific immune responses.

Isolation and characterization of the promoter and flanking regions of the gene encoding the human protein-synthesis-initiation factor 2 alpha.

The promoter region of the gene (eIF-2 alpha) for eukaryotic initiation factor 2 alpha (eIF-2 alpha) was isolated from a human genomic library and its structure was determined by restriction mapping and nucleotide (nt) sequence analysis. The promoter region and twelve in vivo transcriptional start points (tsp) have been identified by endonuclease S1 mapping and their location confirmed by primer-extension analysis, using RNA isolated from human cells. The untranslated leader is 102 to 140 nt long depending upon the tsp, and the 5' region of the mRNA has the potential for forming stable stem-loop structures. The nt sequence of the regions upstream and downstream from the tsp contains neither a 'TATA box' nor a 'CAAT box', but does contain several direct and inverted repeats, as well as palindromic sequences near the tsp. In addition, multiple consensus binding sites for a wide variety of regulatory proteins are present throughout upstream and downstream tsp-flanking regions.

Surgical pathology of hyperparathyroidism. Usefulness of fat stain and problems in interpretation.

Thirty-six adult patients with classical hyperparathyroidism had parathyroidectomy in which tissue evaluation included oil red O stains. Neutral lipid staining has been reported to distinguish hyperfunctioning parathyroid from suppressed or normal tissue. In normal glands, parathyroid chief cells show abundant coarse and fine intracytoplasmic neutral lipid droplets. In contrast, the cytoplasm of chief cells is essentially free of neutral lipid droplets in adenomatous, hyperplastic, or carcinomatous glands. This study shows that to limit or alter surgical exploration solely on the basis of the findings of the oil red O technique will lead to significant judgmental error (6/36 patients). Such errors are especially likely in the patient who has enlarged parathyroid glands containing a normal distribution of parenchymal to adipose tissue. There was excellent agreement between clinical outcome, surgical-pathological findings, and the oil red O stain in 30 cases of parathyroid adenoma, nodular hyperplasia, and a control group (12 patients) who had biopsies of normal parathyroid tissue during the course of thyroidectomy.

BMS-180560, an insurmountable inhibitor of angiotensin II-stimulated responses: comparison with losartan and EXP3174.

1. This study compares the activity of BMS-180560 (2-butyl-1-chloro-1-[[1-[2-(2H-tetrazol-5-yl)phenyl]-1H-indol-4- yl]methyl]-1H-imidazole-5-carboxylic acid), an insurmountable angiotensin II (AII) receptor antagonist, with that of losartan and EXP3174 in functional and biochemical models of AII-receptor activation. 2. BMS-180560 selectively inhibited [125I]-Sar1Ile8AII ([125I]SI-AII) binding to rat aortic smooth muscle (RASM) cell and rat adrenal cortical AT1 receptors (Ki = 7.6 +/- 1.2 and 18.4 +/- 3.9 nM respectively) compared to adrenal cortical AT2 receptors (Ki = 37.6 +/- 1.3 microM). The Ki values of BMS-180560 and EXP3174, but not losartan, varied as a function of the BSA concentration used in the assays, indicating that the diacid drugs bound to albumin. 3. BMS-180560 (3-300 nM) increased the KD of SI-AII for RASM cell AT1 receptors. Only at high concentrations of BMS-180560 (300 nM) were Bmax values decreased. 4. BMS-180560 inhibited AII-stimulated contraction of rabbit aorta with a calculated KB = 0.068 +/- 0.048 nM and decreased maximal AII-stimulated contraction at 1 nM BMS-180560 by 75%. In the presence of 0.1% BSA, a higher KB value (5.2 +/- 0.92 nM) was obtained. Losartan behaved as a competitive antagonist with a KB = 2.6 +/- 0.13 nM. Contraction stimulated by endothelin-1, noradrenaline, KCl, or the TXA2 receptor agonist U-46619 were unaffected by BMS-180560 (1 nM). 5. AII stimulated the acidification rates of RASM cells as measured by a Cytosensor microphysiometer with an EC50 of 18 nM. Losartan (30 nM) shifted the AII concentration-effect curves in a competitive manner whereas BMS-180560 (0.01 and 0.1 nM) decreased the maximum responses by 60 and 75% respectively. Inhibition by losartan and BMS-180560 could be reversed following washout although recovery took longer for BMS-180560. 6. In [3H]-myoinositol-labelled RASM cells, losartan (30 and 200 nM), shifted the EC50 for AII-stimulated [3H]-inositol monophosphaste formation to higher values, with no change in the maximal response. By contrast, EXP3174 (0.1 to 1 nM) decreased the maximal response in a concentration-dependent manner (17-55%). BMS-180560 (3 and 10 nM) increased the EC50 for AII and decreased the maximum response by 30 and 80% respectively. The inhibition by EXP3174 and BMS-180560 could be reversed by inclusion of losartan (200 nM) indicating that the inhibition was not irreversible. 7. In conclusion, BMS-180560 is a potent, specific, predominantly competitive, reversible All receptor antagonist, which displays insurmountable receptor antagonism. At concentrations of BMS-180560 which have no effect on receptor number, BMS-180560 produced insurmountable antagonism of AII-stimulated second messenger formation, extracellular acidification, and smooth muscle contraction.