Viremia control following antiretroviral treatment and therapeutic immunization during primary SIV251 infection of macaques.

Prolonged antiretroviral therapy (ART) is not likely to eradicate human immunodeficiency virus type I (HIV-I) infection. Here we explore the effect of therapeutic immunization in the context of ART during primary infection using the simian immunodeficiency virus (SIV251) macaque model. Vaccination of rhesus macaques with the highly attenuated poxvirus-based NYVAC-SIV vaccine expressing structural genes elicited vigorous virus-specific CD4 + and CD8+ T cell responses in macaques that responded effectively to ART. Following discontinuation of a six-month ART regimen, viral rebound occurred in most animals, but was transient in six of eight vaccinated animals. Viral rebound was also transient in four of seven mock-vaccinated control animals. These data establish the importance of antiretroviral treatment during primary infection and demonstrate that virus-specific immune responses in the infected host can be expanded by therapeutic immunization.

Protection of rhesus macaques against disease progression from pathogenic SHIV-89.6PD by vaccination with phage-displayed HIV-1 epitopes.

The antigenic polymorphism of HIV-1 is a major obstacle in developing an effective vaccine. Accordingly, we screened random peptide libraries (RPLs) displayed on phage with antibodies from HIV-infected individuals and identified an array of HIV-specific epitopes that behave as antigenic mimics of conformational epitopes of gp120 and gp41 proteins. We report that the selected epitopes are shared by a collection of HIV-1 isolates of clades A-F. The phage-borne epitopes are immunogenic in rhesus macaques, where they elicit envelope-specific antibody responses. Upon intravenous challenge with 60 MID50 of pathogenic SHIV-89.6PD, all monkeys became infected; however, in contrast to the naive and mock-immunized monkeys, four of five mimotope-immunized monkeys experienced lower levels of peak viremia, followed by viral set points of undetectable or transient levels of viremia and a mild decline of CD4+ T cells, and were protected from progression to AIDS-like illness. These results provide a new approach to the design of broadly protective HIV-1 vaccines.

A recombinant human receptor antagonist to interleukin 1 improves survival after lethal endotoxemia in mice.

Interleukin 1 (IL-1) is an endogenously produced cytokine that mediates a variety of physiological effects that may be beneficial or deleterious to the host. C57Bl/6 mice treated intravenously with a recently characterized human recombinant receptor antagonist protein to IL-1 (IL-1ra) had improved survival when treated after a lethal Escherichia coli endotoxin (lipopolysaccharide [LPS]) challenge. IL-1ra was effective when treatment was initiated after LPS, and intravenous administration every 4 h for 24 h was required. Serum levels of tumor necrosis factor (TNF) activity after LPS and in vitro TNF cytotoxicity were not altered by treatment with IL-1ra. These experiments provide direct evidence that the lethal effects of LPS may be mediated through the action of IL-1 and that the IL-1ra can provide a new treatment strategy for disease processes mediated via this cytokine.

Differentiation factor/leukemia inhibitory factor protection against lethal endotoxemia in mice: synergistic effect with interleukin 1 and tumor necrosis factor.

Differentiation factor (D factor), also called leukemia inhibitory factor (LIF), is a glycoprotein that has been increasingly recognized to possess a wide range of physiological activities. We examined the possibility that the administration of D factor may confer beneficial effects and enhance host resistance against lethal endotoxemia. A single intravenous dose of recombinant human D factor completely protected C57/Bl6 mice from the lethal effect of Escherichia coli endotoxin (lipopolysaccharide [LPS]). The protective effects were dose dependent and observed when administered 2-24 h before LPS. Previous work has shown that interleukin 1 (IL-1) and tumor necrosis factor (TNF) also protect against a subsequent LPS challenge in a dose-dependent manner. When human D factor was combined with sub-protective doses of IL-1 beta or TNF-alpha, there was dramatic synergistic protection against a subsequent lethal LPS challenge.

Changes in interleukin-2 and interleukin-4 production in asymptomatic, human immunodeficiency virus-seropositive individuals.

Infection with HIV results in an incremental loss of T helper cell (TH) function, which can occur years before CD4 cell numbers are critically reduced and AIDS is diagnosed. All TH function is not affected, however, because B cell activation and hypergammaglobulinema are also characteristic of this period. Recently, in a murine model of AIDS an early loss in production of the CD4 cytokines IL-2 and IFN-gamma was correlated with an increase in the B cell stimulatory cytokines IL-4, IL-5, and IL-10. We therefore assessed the production of IL-4 generated by PBL from HIV-seropositive (HIV+) individuals who did not have AIDS, yet who exhibited different TH functional categories based on their IL-2 production profiles. We observed that the decreases in recall antigen-stimulated IL-2 production were accompanied by an increase in IL-4 production. The loss of recall antigen-stimulated responses in HIV+ individuals could be reversed in vitro by anti-IL-4 antibody. Our results suggest that the TH functions assessed by IL-4 production replace the normally dominant TH function of antigen-stimulated IL-2 production in the progression toward AIDS, and raise the possibility of cytokine cross-regulation in AIDS therapy.

Treatment with recombinant human tumor necrosis factor-alpha protects rats against the lethality, hypotension, and hypothermia of gram-negative sepsis.

Tumor necrosis factor (TNF) is a peptide secreted by macrophages in response to endotoxin that can produce many of the changes seen in septic shock. After cecal ligation and puncture (CLP) rats gradually develop tachycardia, hypotension, tachypnea, and hypothermia. At 5 h post-CLP, rats have a peak in serum levels of endotoxin and 60% of rats have blood cultures that grow Gram-negative rods (Escherichia coli and Klebsiella pneumonia). At 20 h post-CLP all rats develop positive blood cultures. Serum levels of TNF are not reproducibly measurable in rats following CLP. Rats undergoing CLP have a 50-80% mortality with deaths usually occurring 24-72 h postinjury. Repetitive (twice daily x 6 d) i.p. injection of sublethal doses of recombinant human TNF-alpha (100 micrograms/kg) to rats undergoing CLP 1 d after the treatment period resulted in a significant reduction in mortality compared to control rats previously unexposed to rTNF (P less than 0.03). Animals treated with rTNF had no hypotension or hypothermia after CLP and regained normal food intake faster than control rats. 12 h after CLP the gene expression for manganous superoxide dismutase (MnSOD), an inducible mitochondrial metalloenzyme responsible for cellular resistance to injury from toxic reactive oxygen species, was higher in livers of rats treated with rTNF suggesting that the TNF treatment augmented expression of this protective enzyme. Unlike MnSOD, expression of the gene for copper-zinc SOD was not affected by CLP or rTNF treatment. The results suggest that prior treatment with recombinant TNF can ameliorate the lethality, hypotension, hypothermia, and anorexia of Gram-negative sepsis in rats and that the mechanism may be related to enhanced hepatic expression of the gene for MnSOD. Repeated administration of recombinant TNF may be a strategy to minimize mortality and morbidity of Gram-negative sepsis.

Host defense molecule polymorphisms influence the risk for immune-mediated complications in chronic granulomatous disease.

Chronic granulomatous disease (CGD) is an inherited disorder of phagocyte function in which defective superoxide production results in deficient microbicidal activity. CGD patients suffer from recurrent, life-threatening infections, and nearly half develop chronic gastrointestinal (GI) complications (colitis, gastric outlet obstruction, or perirectal abscess) and/or autoimmune/rheumatologic disorders (AIDs). To identify genetic modifiers of disease severity, we studied a cohort of 129 CGD patients, in whom seven candidate genes (myeloperoxidase [MPO], mannose binding lectin [MBL], Fcgamma receptors IIa, IIIa, IIIb, TNF-alpha, and IL-1 receptor antagonist), each containing a physiologically relevant polymorphism predicted to influence the host inflammatory response, were selected for analysis. Genotypes of MPO (P = 0.003) and FcgammaRIIIb (P = 0.007) were strongly associated with an increased risk for GI complications, while an FcgammaRIIa (P = 0.05) genotype was suggestive for an association. Patients with all three associated genotypes had the highest risk for GI complications (P < 0.0001). The risk of AIDs was strongly associated with variant alleles of MBL (P = 0.01) and weakly associated with an FcgammaRIIa genotype (P = 0.04). Patients with variant forms of both MBL and FcgammaRIIa had the highest risk of developing an AID (P = 0.003).

HIV infection--induced posttranslational modification of T cell signaling molecules associated with disease progression.

In attempt to elucidate the mechanism of the HIV infection induced T cell unresponsiveness, we studied signal-transducing molecules proximal to the T cell receptor (TCR) in T lymphocytes of HIV-infected individuals. Total amounts of protein tyrosine kinases (PTKs) Lck, Fyn, and ZAP-70 and the zeta chain of the TCR were found significantly decreased in T cells of symptomatic/AIDS patients as well as in T cells of individuals in acute and early asymptomatic stages of HIV infection. Unexpectedly, the detection of Lck, Fyn, and ZAP-70 was reversed after the treatment of cell lysates with dithiothreitol. This suggests that PTKs Lck, Fyn, and ZAP-70 were modified by a mechanism altering the status of sulfhydryl groups. Moreover, this mechanism seems to affect selectively T cells of HIV infected patients since B cell PTKs Syk and Lyn were detected structurally and functionally intact. Interestingly, similar alterations of signaling molecules were not detected in T cells of HIV-infected long-term asymptomatic individuals. Modification of T cell PTKs may thus underlie the HIV-induced impairment of lymphocyte function and may potentially predict disease progression.

Effect of raloxifene on bone mineral density in premenopausal women at increased risk of breast cancer.

CONTEXT: Raloxifene is a promising breast cancer prevention agent in postmenopausal women at increased risk for breast cancer. The effects of raloxifene in premenopausal women are unknown. OBJECTIVE: We evaluated the effect of raloxifene in premenopausal women at increased risk for breast cancer on bone mineral density (BMD). DESIGN: This was a phase II clinical trial. SETTING: This study was conducted at an academic medical center. PARTICIPANTS: Thirty-seven premenopausal women at increased risk for breast cancer enrolled in the trial. Thirty subjects began treatment and 27 were evaluable. INTERVENTION: Raloxifene (60 mg daily) and elemental calcium (500 mg daily) were given for 2 yr. Subjects were followed up off medications for 1 yr. MAIN OUTCOME MEASURE: The primary end point was the intrasubject percent change in BMD at 1 yr measured by dual-energy x-ray absorptiometry. RESULTS: The mean baseline lumbar spine density was 1.027 g/cm(2). Lumbar spine density decreased 2.3% at 1 yr (P < 0.00001) and 3.5% at 2 yr (P < .00001). Percent change from yr 2 to 3 was +1.4%. The mean baseline total hip bone density was 0.905 g/cm(2). Total hip density decreased 0.3% at 1 yr and 1.0% at 2 yr (P = 0.033). Percent change from yr 2 to 3 was +1.7%. CONCLUSIONS: Raloxifene use is associated with a decrease in BMD in premenopausal women at increased risk for breast cancer. The clinical significance of this decrease is unknown and is attenuated with stopping raloxifene.

Cytokine production patterns in cervical intraepithelial neoplasia: association with human papillomavirus infection.

BACKGROUND: Genital infection with certain strains of human papillomavirus (HPV) is associated with a high risk of malignant transformation, and HPV-associated cervical intraepithelial neoplasia (CIN) can become invasive cancer. Host factors are critical in regulating tumor growth, and cytokines that modulate immunologic control may be of particular importance. The type 1 cytokines interleukin 2 (IL-2) and interferon gamma (IFN gamma) are immunostimulatory and are thus capable of limiting tumor growth. The type 2 cytokines interleukin 4 (IL-4) and interleukin 10 (IL-10) are immunoinhibitory and are thus capable of stimulating tumor growth. PURPOSE: We analyzed the production of cytokines by peripheral blood mononuclear cells (PBMCs) in women with CIN associated with localized or extensively spread HPV infection. METHODS: Thirty women diagnosed with CIN and 10 age- and sex-matched healthy control subjects were enrolled in the study conducted at Istituto Nazionale Tumori, Milan, Italy. The following parameters were analyzed: 1) HPV infection of the cervix and other sites of the lower genital tract by colposcopic, cytologic, and histologic examinations; 2) HPV typing; 3) in vitro production of IL-2 by PBMCs in response to stimulation with soluble antigen (influenza [FLU] antigen) or to cell-associated human leukocyte antigen (HLA) alloantigen; and 4) in vitro production of the type 1 cytokines IL-2 and IFN gamma and of the type 2 cytokines IL-4 and IL-10 by PBMCs in response to mitogen stimulation. Statistical significance was determined by nonparametric tests (two-sided). RESULTS: High-grade CIN associated with HPV infection was detected in all case patients, and HPV type 16 or 18 infection was detected in cervical tissue of 21 (70%) of 30 case patients. HPV infection that had spread to other sites of the lower genital tract, thus resulting in more extensive disease, was detected in 16 (53%) of the 30 individuals with CIN, whereas HPV infection was limited to the portio in 14 (47%). IL-2 production by PBMCs in response to stimulation with soluble antigen or HLA alloantigen was reduced in the group with extensive disease compared with that in the group with localized disease or with that in healthy control subjects. In contrast, IL-4 and IL-10 production in response to mitogen stimulation was elevated in the group with extensive disease compared with that in the group with localized disease or with that in healthy control subjects. The highest production of IL-4 and IL-10 was detected in patients with HPV infection that had extended beyond the genital tract. CONCLUSIONS: CIN is characterized by different immunologic profiles, in which HPV infection is or is not confined to the portio. Production of cytokines that mainly enhance potentially protective cell-mediated immunity is defective in the women in whom extended HPV infection was observed. A pronounced shift from type 1 to type 2 cytokine production is associated with more extensive HPV infection. IMPLICATIONS: These data reinforce the need for detailed analyses of immune dysregulation in CIN patients. They also suggest the potential usefulness of the cytokine assays for determining prognosis or deciding whether cytokine-based therapy is indicated.

Prolonged survival of tumor-bearing rats with repetitive low-dose recombinant tumor necrosis factor.

Tumor necrosis factor may be a mediator of the syndrome of cancer cachexia. Tachyphylaxis or tolerance to the cachectic effects of recombinant tumor necrosis factor (rTNF) has been previously described. In this study, we investigate whether repetitive exposure to rTNF can induce similar tolerance in tumor-bearing (TB) rats and ameliorate cachexia induced by the tumor. In experiment 1, non-tumor-bearing (NTB) and TB rats were randomized to either escalating low doses of rTNF or saline i.p. twice daily for 9 consecutive days. NTB rats treated with rTNF demonstrated a significant decline in food intake and weight change (P less than 0.00001) but soon developed tolerance to the cachectic effects of rTNF; they consumed significantly more food than on the first day of treatment and had weight change similar to NTB rats treated with saline. TB rats treated with rTNF showed a similar significant decline in food intake and weight change (P less than 0.0001) and also demonstrated similar tolerance to the cachectic effects of rTNF with continued treatment. Following treatment, TB rats that had been treated with rTNF ate significantly more and lost less weight than TB rats that had been treated with saline (P less than 0.00001). rTNF treatment of TB rats also demonstrated antineoplastic activity, as estimated tumor weight of tumors from rats treated with rTNF were significantly less than controls (P = 0.003). The anticachexia and antineoplastic effects of rTNF resulted in prolonged survival of TB rats treated with rTNF compared to control TB rats (P = 0.015). Experiment 2 utilized two different rTNF treatment regimens in TB rats: one group received 12 days of escalating doses of rTNF, and another group received 15 days of rTNF treatment. TB rats treated with rTNF again had a significantly greater food intake (P less than 0.00001) and delayed weight loss (P = 0.0001) posttreatment that was further augmented by additional doses of rTNF. Antineoplastic activity of rTNF was less clear, and overall tumor growth curves were not affected by rTNF treatment. Survival of TB rats treated with rTNF was again significantly increased in a dose-dependent manner (P = 0.006). Repeated administration of low doses of rTNF to TB rats induces mild reduction in tumor growth, tolerance to the cachectic effects of rTNF that results in tolerance to the cachectic effects of tumor, and prolongation of survival.

Tempol, a stable free radical, is a novel murine radiation protector.

Nitroxide compounds are stable free radicals which were previously investigated as hypoxic cell radiosensitizers. The stable nitroxide 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl (Tempol) has recently been shown to protect aerated cells in culture against superoxide generated from hypoxanthine/xanthine oxidase, hydrogen peroxide, and radiation-induced cytotoxicity and to modestly sensitive hypoxic cultured cells. To extend these observations from the cellular level to the whole animal, the toxicity, pharmacology, and in vivo radioprotective effects of Tempol were studied in C3H mice. The maximum tolerated dose of Tempol administered i.p. was found to be 275 mg/kg, which resulted in maximal Tempol levels in whole blood 5-10 min after injection. Mice were exposed to whole-body radiation in the absence or presence of injected Tempol (275 mg/kg) 5-10 min after administration. Tempol treatment provided significant radioprotection (P less than 0.0001); the dose of radiation at which 50% of Tempol-treated mice die at 30 days was 9.97 Gy, versus 7.84 Gy for control mice. Tempol represents a new class of in vivo, non-sulfur-containing radiation protectors. Given the potential for hypoxic radiosensitization and aerobic cell radioprotection, Temporal or other analogues may have potential therapeutic application.

HLA association with response and toxicity in melanoma patients treated with interleukin 2-based immunotherapy.

Peripheral blood lymphocytes from 146 patients with metastatic melanoma undergoing interleukin 2 (IL-2)-based immunotherapy were characterized for HLA A, B, Cw, DR, DQw, and DRw specificities. Patients had been enrolled into sequential treatment protocols with either IL-2 alone (28) or in combination with tumor-infiltrating lymphocytes (TILs) (86), alpha-interferon (26), lymphokine-activated killer cells (16), radiation therapy (7), cyclophosphamide (3), tumor necrosis factor (1), and interleukin 4 (1) for a total of 168 courses of therapy. HLA phenotype was then correlated with response rate and toxicity to IL-2. We noted: (a) a significant difference in the frequency of A11 (20.5% versus 10.2%; P < 0.05) allele between melanoma patients and the North American Caucasian population; (b) a significantly higher frequency of A11 phenotype among responders (40.5%) than in the melanoma patient population (20.5%; P < 0.01), which was even more obvious among patients responding to TIL therapy (47.4% versus 22.1%; P < 0.05); within TIL patients, responders also had an increased frequency of A19 (42.1% versus 25.6%; P < 0.05); (c) a correlation between the number of TILs received and response rate (P < 0.005); and (d) an association between DR4 haplotype and decreased tolerance to IL-2 among the patients receiving TILs (P = 0.01). These results suggest that, in melanoma patients, some HLA Class I specificities may predict for a greater likelihood of response to IL-2-based therapy, while HLA Class II phenotype correlates with tolerance to the combination of TIL and IL-2 therapy.

In vivo radiation protection by nitric oxide modulation.

Drugs that affect blood flow have been shown to be whole body radiation protectors. Using NG-nitro-L-arginine, a specific inhibitor of nitric oxide synthase, and the NO-releasing agent (C2H5)2N[N(O)NO-]Na+ (DEA/NO), we have studied the ability of NO to modulate whole body radiation toxicity in C3H mice. NG-Nitro-L-arginine given to mice between 15 and 60 min prior to radiation afforded significant protection from whole body irradiation, e.g., the estimated whole body irradiation dose required to kill 50% of mice by 30 days after radiation (LD50/30) in mice treated with NG-nitro-L-arginine 60 min before irradiation was 1051 cGy compared with a whole body radiation LD50/30 of 822 cGy in control mice (P < 0.00001). Treatment of mice with DEA/NO prior to whole body irradiation also significantly reduced toxicity; the estimated whole body radiation LD50/30 was 1063 and 945 cGy in mice treated with DEA/NO 10 or 30 min before irradiation, respectively (P < 0.00001 for radiation LD50/30 of either DEA/NO-treated group compared with control). Measurement of [14C]etanidazole binding to bone marrow demonstrated that DEA/NO and NG-nitro-L-arginine exacerbated bone marrow hypoxia. Perturbations of NO levels have profound effects on in vivo radiosensitivity of normal tissues. We hypothesize that alterations in regional blood flow may underlie the changes in radiosensitivity that we have observed.

Abnormal fragile histidine triad (FHIT) expression in advanced cervical carcinoma: a poor prognostic factor.

The FHIT gene is a candidate tumor suppressor gene that has been implicated in the development of cervical carcinoma. We hypothesized that abnormal Fhit expression might be a poor prognostic factor for patients with cervical cancer. The tumors from 59 high-risk patients (stage II-III) were evaluated for abnormal Fhit expression by immunohistochemical staining. Abnormal Fhit expression (absent or reduced) was noted in 66% of the specimens. There was no statistical difference with respect to stage, performance status, para-aortic node metastasis, completion of therapy, grade, race, age, and HIV status between the normal and abnormal Fhit expression groups. The 3-year survival for patients whose tumors displayed normal Fhit expression versus abnormal Fhit expression was 74% versus 37%, respectively. Univariate analysis demonstrated a difference in survival that was statistically significant for age <55 years versus > or =55 years (P = 0.015), normal Fhit expression versus abnormal Fhit expression (P = 0.015), and stage II versus stage III (P = 0.033). Multivariate analysis showed that abnormal Fhit expression was a poor prognostic factor (P = 0.015).

Lack of in vitro synergy between etoposide and cis-diamminedichloroplatinum(II).

Claims of synergy between etoposide and cisplatin have been based upon preclinical in vivo murine P388 models or upon human clinical trials in tumors such as lung cancer. Such in vivo studies are useful in exploring therapeutic synergy, i.e., an improved therapeutic strategy. The term "synergy" in this context is sometimes, however, taken to imply greater than additive kill of tumor cells. Unfortunately, it is virtually impossible to document supra-additive tumor cell kill in vivo, since in vivo curves of therapeutic effect are not linear and drugs are therefore not additive with themselves. Therapeutic synergy may, in fact, occur when two drugs are merely additive (or even antagonistic) with regard to cytotoxicity if the drugs have nonoverlapping host toxicity. The demonstration of true supra-additive cell kill would imply an interaction of the two agents at a cellular level and would have profound implications for biochemical studies. In order to determine whether the reported therapeutic synergy of etoposide and cisplatin is due, in part, to supra-additive cell kill, we used an in vitro tetrazolium-based colorimetric assay for cytotoxicity (MTT assay) and an isobologram analysis to test combinations of the two drugs against four human small cell and four human non-small cell lung carcinoma lines. Using a rigorous test for in vitro synergy, we could not establish a greater than additive cytotoxic effect on our cell lines. It thus appears that the clinical synergy between etoposide and cisplatin is not due to a supra-additive effect at the cellular level. Our results have implications for a variety of fields in which claims of "synergy" often appear.

Increased level of stromal cell-derived factor-1 mRNA in peripheral blood mononuclear cells from children with AIDS-related lymphoma.

A common polymorphism in the 3' untranslated region of the stromal cell-derived factor 1 (also called pre-B-cell-stimulating factor) beta gene transcript, termed SDF1-3'A, has been associated with an increased risk of non-Hodgkin's lymphoma (NHL) in HIV-1-infected, but not in uninfected, individuals. Because the gene variation is located within the 3' untranslated region, the SDF1-3'A may influence the abundance of SDF-1 mRNA, possibly up-regulating the chemokine expression especially in the presence of HIV-1. In the current study, we investigated the levels of SDF-1 mRNA in peripheral blood mononuclear cells and HIV-1 viral load in 84 HIV-1-infected children (0.7 to 18 years of age; median, 5.8), including 12 children who developed NHL during their illnesses (AIDS-NHL group; 8 with SDF1-3'A, 4 with SDF1-wild-type). High level SDF-1 expression was observed in 15 of 34 children with SDF1-3'A as compared with 10 of 50 with wild type (P < 0.03). More notably, the children with AIDS-NHL had significantly elevated levels of SDF-1 mRNA in peripheral blood mononuclear cells, obtained at the time of presentation in 10 children and 8.5 to 19.4 months before (median, 15 months) in 7 children, as compared with the children in the non-NHL group (P < 0.00001). The amounts of cell-associated HIV-1 DNA and singly spliced HIV-1 mRNA were significantly greater in children with AIDS-NHL than those with non-NHL AIDS (P = 0.0052 and 0.011, respectively; stratified by antiretroviral treatment regimen), whereas their serum HIV-1 RNA levels were comparable. Overexpression of SDF-1 and aberrant HIV-1 expression in circulating lymphocytes appear to be linked to the development of AIDS-lymphoma. Additional studies are required to determine whether excessive SDF-1, together with virally encoded factors, is directly involved in the pathogenesis of AIDS-lymphoma.

A phase I and pharmacokinetic study of intravenous phenylacetate in patients with cancer.

Phenylacetate has recently been shown to suppress tumor growth and promote differentiation in experimental models. A phase I trial of phenylacetate was conducted in 17 patients with advanced solid tumors. Each patient received a single i.v. bolus dose followed by a 14-day continuous i.v. infusion of the drug. Twenty-one cycles of therapy were administered at four dose levels, achieved by increasing the rate of the continuous i.v. infusion. Phenylacetate displayed nonlinear pharmacokinetics [Km = 105.1 +/- 44.5 (SD) microgram/ml, Vmax = 24.1 +/- 5.2 mg/kg/h and Vd = 19.2 +/- 3.3 L]. There was also evidence for induction of drug clearance. Ninety-nine % of phenylacetate elimination was accounted for by conversion to phenylacetylglutamine, which was excreted in the urine. Continuous i.v. infusion rates resulting in serum phenylacetate concentrations exceeding Km often resulted in rapid drug accumulation and dose-limiting toxicity, which consisted of reversible central nervous system depression, preceded by emesis. Three of nine patients with metastatic, hormone-refractory prostate cancer maintained stable prostatic specific antigen levels for more than 2 months; another had less bone pain. One of six patients with glioblastoma multiforme, whose steroid dosage has remained unchanged for the duration of therapy, has sustained functional improvement for more than 9 months. The use of adaptive control with feedback for the dosing of each patient enabled us to safely maintain stable phenylacetate concentrations up to the range of 200-300 micrograms/ml, which resulted in clinical improvement in some patients with advanced disease.

Somatic mutations of the MEN1 tumor suppressor gene in sporadic gastrinomas and insulinomas.

Gastrinomas and insulinomas are frequent in multiple endocrine neoplasia type 1 (MEN1). The MEN1 tumor suppressor gene was recently identified. To elucidate the etiological role of the MEN1 gene in sporadic enteropancreatic endocrine tumorigenesis, we analyzed tumors (28 gastrinomas and 12 insulinomas) from 40 patients for MEN1 gene mutations and allelic deletions. One copy of the MEN1 gene was found to be deleted in 25 of 27 (93%) sporadic gastrinomas and in 6 of 12 (50%) sporadic insulinomas. MEN1 gene mutations were identified in 9 of 27 (33%) sporadic gastrinomas and 2 of 12 (17%) insulinomas and were not seen in corresponding germ-line DNA sequence. A specific MEN1 mutation was detected in one gastrinoma and in the corresponding germ-line DNA of a patient who had no family history of MEN1. Somatic MEN1 gene mutations and deletions play a critical role in the tumorigenesis of sporadic gastrinomas and may also contribute to the development of a subgroup of insulinomas.

Risk of second aerodigestive cancers increases in patients who survive free of small-cell lung cancer for more than 2 years.

PURPOSE: Patients who survived small-cell lung cancer (SCLC) for more than 2 years were evaluated to determine the frequency and anatomic pattern of redevelopment of small-cell cancer and development of non-small-cell lung cancer (NSCLC) and aerodigestive cancers with the passage of time. PATIENTS AND METHODS: From April 1973 through December 1991, 578 patients with previously untreated SCLC were entered onto prospective therapeutic trials at the National Cancer Institute (NCI), Bethesda, MD. Sixty-two (11%) were cancer-free 2 years after initiation of therapy and were assessable for redevelopment of SCLC and development of NSCLC, and aerodigestive cancers. RESULTS: Twenty patients redeveloped SCLC 2.0 to 12.2 years after initiation of chemotherapy, of whom two patients were deemed to have a second primary small-cell cancer that involved the aerodigestive tract. Fifteen patients developed 16 cancers in the lung other than SCLC 3.4 to 14.9 years after initiation of therapy. Two developed other aerodigestive cancers that involved the larynx and lip. The risk of a NSCLC and aerodigestive cancer in these patients increased more than sixfold from 2% per patient per year during years 2 to 4 to 12.6% and 14.4%, respectively, after more than 10 years. The cumulative actuarial risk of a second primary NSCLC or aerodigestive cancer at 16 years is 69% and 72%, respectively. CONCLUSION: The increasing risk of second aerodigestive cancers with the passage of time is a mounting problem for patients cured of SCLC. Chemoprevention trials for these patients should be considered.