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Biomedical subjects

B Storer

Publications and source records attributed to B Storer.

At least 19 recordsLinked to original sources

Clinical and biologic effects of combination therapy with gamma-interferon and tumor necrosis factor.

Tumor necrosis factor (TNF) and gamma-interferon (gamma-IFN) are cytokines with synergistic biologic and antiproliferative effects in vitro and in mouse models. The biologic effects of the combination of TNF and gamma-IFN, however, have not been studied well in humans. A Phase I trial was conducted of TNF and gamma-IFN therapy in 24 patients with advanced malignancies to determine the tolerability of the combination and the biologic effects of TNF and gamma-IFN in vivo. Both TNF and gamma-IFN were administered as 30-minute intravenous infusions three times per week. Doses of TNF ranged from 25 to 100 micrograms/m2; all patients received 100 micrograms/m2 of gamma-IFN. Dose-limiting toxicity consisted primarily of orthostatic hypotension and constitutional symptoms. The maximum tolerated dose level (MTDL) of 50 micrograms/m2 of TNF and 100 micrograms/m2 of IFN-gamma was less than the maximum tolerated dose (MTD) observed in previous Phase I trials of gamma-IFN and TNF alone. Biologic responses were studied in seven patients treated at the MTDL. Serum interleukin-2 receptor levels and neopterin secretion were enhanced significantly 24 hours after therapy (P = 0.002); enhancement of monocyte Fc receptor levels had borderline statistical significance (P = 0.07). With the exception of the mean fluorescent intensity on monocytes positive for histocompatibility antigen HLA-DR (P = 0.03), HLA Class I and II cell surface protein expression was not increased. The combination significantly enhanced indoleamine dioxygenase activity and serum beta 2-microglobulin expression (P less than 0.04) but not 2',5'-oligoadenylate synthetase activity, bactericidal function, or chemiluminescence. These results were compared retrospectively with those observed in previous Phase I trials of gamma-IFN and TNF alone. The combination of TNF and gamma-IFN significantly increased urinary kynurenine levels more than either TNF alone or gamma-IFN alone. Given the limitations inherent in any retrospective analysis, however, the enhancement in the other biologic parameters measured at the MTDL during this trial did not differ significantly from the changes observed at the MTD of either TNF or gamma-IFN alone. It was concluded that the combination of TNF and gamma-IFN, when administered at the MTDL of the combination, does not offer any enhancement in biologic responses over either agent alone.

2',5'-Oligoadenylate Synthetase

Effect of nifedipine on cyclosporine A-induced nephrotoxicity, urinary endothelin excretion and renal endothelin receptor number.

The aim of the present study was to determine the effect of a calcium channel blocker on renal function, urinary endothelin excretion and endothelin receptor number in rats. Administration of cyclosporine resulted in a significant impairment of renal function when measured by either [14C]inulin or 24 h creatinine clearances. This nephrotoxicity was associated with statistically significant (P less than 0.05) increases in urinary endothelin excretion and renal endothelin receptor number. Treatment with nifedipine attenuated cyclosporine A-induced renal dysfunction and reduced urinary endothelin excretion. The data provide further evidence of a role for endothelin in cyclosporine A-induced nephrotoxicity.

Animals

Modulation of U937 cell adhesion to vascular endothelial cells by cyclic AMP.

Adhesion of leukocytes to the endothelium is an essential event in inflammatory cell emigration from intravascular to extravascular compartment. While many mediators (e.g. cytokines) enhance cell adhesion through expression of adhesion molecules on endothelial cells the mechanism of this phenomenon is not known. In this study we examined the role of cAMP in mediation of the adhesion of monocytic cell line, U937 to human umbilical vein endothelial cells (HUVEC). Incubation of HUVEC with cholera toxin (10-500 ng/ml) for 4 hrs greatly enhanced the adhesiveness of HUVEC for U937 cells. The magnitude of adhesion stimulation produced by cholera toxin was comparable to that produced by the cytokines TNF alpha or IL-1 (2-3 folds). Upregulation of U937 cells adhesion to HUVEC was also achieved by short incubation (less than 1 hr) of HUVEC with cAMP elevating agents such as forskolin (10 microM), isoproterenol (0.3-30 microM), epinephrine (10-100 microM), norepinephrine (100 microM) as well as by endogenously added dibutyryl cAMP (0.05-2.0 mM). Dibutyryl cyclic GMP (0.05-2.0 mM) was ineffective in promoting adhesion. These data suggest that cAMP might be an important intracellular modulator of leukocyte adhesion to endothelium and therefore promoter of pro-inflammatory processes.

Adrenergic beta-Agonists

Development of a small RGD peptide fibrinogen receptor antagonist with potent antiaggregatory activity in vitro.

The development of potent antithrombotic agents from the fibrinogen platelet receptor binding sequences Fg-alpha 572-575 -Arg-Gly-Asp-Ser- and Fg-gamma 400-411 -HHLGGAKQAGDV, believed to be a cryptic RGD-type sequence, is described. The tetrapeptide Ac-RGDS-NH2 itself is capable of inhibiting platelet aggregation in vitro at high concentrations, IC50 91.3 +/- 0.1 microM [in vitro antiaggregatory activity employing dog platelet rich plasma (PRP)/ADP], due to low platelet fibrinogen receptor affinity, Ki 2.9 +/- 1.9 microM (purified, reconstituted human platelet GPIIb/IIIa), relative to fibrinogen, Ki 38.0 +/- 6.0 nM. The peptide is also unstable to plasma, suffering total loss of in vitro activity upon incubation in PRP for 3 h (T1/2 90 min). Only modest improvements in potency were achieved with linear analogues of Ac-RGDS-NH2, while dramatic results were achieved with cyclic analogues, culminating in the cyclic disulfide Ac-cyclo-S,S-[Cys-(N alpha-Me)Arg-Gly-Asp-Pen]-NH2 (SK&F 106760) with improved plasma stability (100% activity after 3 h), affinity (Ki 58 +/- 20 nM purified human receptor), and potency (IC50 0.36 +/- 0.4 microM dog PRP/ADP). The affinity of this peptide is 2 orders of magnitude greater than that of Ac-RGDS-NH2. The affinity of the analogue is also comparable to fibrinogen. This peptide constitutes a first potent small peptide entry into the class of novel antithrombotic agents called fibrinogen receptor antagonists.

Amino Acid Sequence

Increased endothelin excretion in rats with renal failure induced by partial nephrectomy.

1. Six weeks following partial nephrectomy in rats, significant increases in serum urea nitrogen and serum creatinine concentration and a significant decrease in creatinine clearance were observed. 2. Measurement of systolic blood pressure by tail plethysmography indicated that animals that had undergone partial nephrectomy were hypertensive. 3. Compared to sham-operated animals, there were 4 fold increases in both urinary protein excretion and urinary endothelin excretion. 4. There was a significant correlation between urinary protein and urinary endothelin excretion (r = 0.77). There was also a correlation (r = 0.65) between urinary endothelin excretion and systolic blood pressure. 5. Plasma endothelin concentrations were not different in sham-operated and partially nephrectomized rats. 6. The data indicate that there is an increased renal endothelin production in rats with chronic renal failure.

Animals

Prolonged interleukin-2 (IL-2) treatment can augment immune activation without enhancing antitumor activity in renal cell carcinoma.

Preliminary studies involving small numbers of patients have suggested that interleukin-2 (IL-2) administered by continuous infusion in repetitive weekly cycles using doses of 3 x 10(6) U/M2/day is immunologically active and can induce tumor responses in patients with renal cell carcinoma. This study was designed to examine both the immunological and clinical effects of prolonged infusion IL-2 given by repetitive weekly cycles; first at moderate doses for 4 weeks as an impatient followed by lower doses of IL-2 for up to 5 months. Prolonged IL-2 treatment was investigated because previous studies revealed that patients had a return to their baseline immune status within 4 weeks after completing IL-2 treatment. Twenty-five patients (including 18 with renal cell carcinoma) were treated with one of two regimens utilizing IL-2 as sole therapy. These regimens were designed to induce augmented and prolonged immune activation based upon in vitro and in vivo data. Though patients on both arms of the study demonstrated sustained lymphocytosis, increase in numbers of natural killer cells, and induction of lymphokine-activated killer activity with prolonged IL-2 administration, only 1 out of the 18 patients with renal cell carcinoma demonstrated a sustained partial antitumor response to therapy. Furthermore, several patients demonstrated profound immune activation, without any evidence of tumor regression. The lack of clinical responses in these patients showing marked activation of LAK cytotoxicity suggests that other variables must also influence the likelihood of antitumor effects for patients receiving IL-2 therapy.

Adult

The influence of autologous lymphokine-activated killer cell infusions on the toxicity and antitumor effect of repetitive cycles of interleukin-2.

Twenty patients with refractory malignancies were treated with a protocol evaluating the addition of ex vivo-activated autologous lymphokine-activated killer (LAK) cells to a clinically tolerable interleukin-2 (IL-2) regimen (four weekly cycles of human recombinant IL-2 at 3 x 10(6) U/m2/day by continuous infusion for 4 days/week). Sixteen patients completed their induction month of therapy, two had a partial response, six had stable disease, and eight had progressive disease. Four patients had clinical toxicity preventing completion of the induction month of therapy, and one of these patients died during therapy. Significant clinical toxicities included decreased performance status, weight gain, catheter-related thromboses, infectious complications, fever, hypotension, and dyspnea or hypoxemia requiring oxygen. Thus, the addition of LAK cell infusions to this IL-2 regimen did not cause a noticeable change in antitumor response rate but did not cause more severe toxicity.

Adult

Biological and clinical effects of the combination of beta- and gamma-interferons administered as a 5-day continuous infusion.

A phase I trial involving continuous infusion of both beta- and gamma-interferon (IFN-beta and IFN-gamma) was conducted in 20 patients in order to determine whether combinations of high doses of IFN-beta and IFN-gamma were tolerable when administered under conditions which mimic conditions of in vitro antiproliferative studies. Patients received a 5-day continuous infusion of IFN-beta/IFN-gamma, followed by a 9-day rest period. Two cycles were administered. Doses of IFN-beta/IFN-gamma were escalated between 4 dose levels, with 5 patients per dose level. Dose-dependent side effects, consisting primarily of constitutional symptoms typical of those experienced with IFN, were observed. The maximally tolerated dose of continuous IFN-beta/IFN-gamma infusion was 3 x 10(6) units of IFN-beta and 200 micrograms of IFN-gamma. Dose-limiting side effects consisted of severe headache, fatigue, fever, and hepatic toxicity. No clinical responses were observed. Serum IFN was measurable only at the highest 3 dose levels. Only 5 patients (4 at the highest dose level) had total serum levels which exceeded 50 laboratory units/ml (55, 63, 800, 800, and 550 laboratory units/ml, respectively). In order to confirm the biological effectiveness of this schedule, we measured IFN-inducible proteins prior to therapy, 24 h after the initiation of the infusion, and at the completion of the 5-day infusion. 2'-5'-Oligoadenylate synthetase, serum beta 2-microglobulin, neopterin, and p78 levels all increased significantly, and serum tryptophan decreased significantly within 24 h after the initiation of treatment (P less than 0.0001). A dose-response effect was observed for serum beta 2-microglobulin, neopterin, and p78 (P less than 0.02). We retrospectively compared the results of this trial with those of another IFN-beta/IFN-gamma trial in which IFN-beta and IFN-gamma were administered by i.v. bolus. Within the limitations of a retrospective comparison, continuous infusion was less well tolerated than our previous schedule of bolus administration 3 times/week. However, the continuous infusion schedule appeared to be more effective in enhancing 2'-5'-oligoadenylate synthetase levels in mononuclear cells. We conclude that tolerable doses of IFN-beta and IFN-gamma do not result in serum IFN levels which produce significant synergistic antiproliferative responses in vitro. This study and other findings suggest that, unless higher doses can be achieved, combinations of IFN-beta and IFN-gamma are unlikely to have significant therapeutic activity.

2',5'-Oligoadenylate Synthetase

Endothelin and platelet function.

The effects of newly discovered vasoconstrictor peptide endothelin was studied on human, rabbit and canine platelet function. Endothelin (0.01 nM-1 microM) did not promote platelet aggregation. In human platelets, endothelin (0.1 microM) did not significantly affect aggregation responses to ADP, collagen, epinephrine, arachidonic acid, PGH2 or thrombin. Endothelin did not promote the mobilization of intracellular calcium in Fura2 loaded human platelets. In rabbit and canine platelets endothelin produced significant potentiation of platelet aggregation mediated by low concentrations of ADP. Aggregation responses to higher concentration of ADP (5 microM) were unaffected by endothelin. These data reveal that under certain circumstances endothelin may potentiate rabbit and canine platelet aggregation responses to ADP, however endothelin does not produce direct effects on human platelet function.

Adenosine Diphosphate

Characterization of the synergistic antiproliferative effects of interferon-gamma and tumor necrosis factor on human colon carcinoma cell lines.

We employed a tumor-type-specific tissue culture model utilizing three human colon carcinoma cell lines to (i) assess the effects of schedule, sequence, dose, and duration of exposure on the antiproliferative activity of combinations of tumor necrosis factor (TNF) and interferon-gamma (IFN-gamma) and to (ii) determine the effects of this combination on the production of a TNF-inducible protein, IFN-beta 2, and an IFN-inducible protein, p78. A statistical model was developed to ascertain the effects of each of three of the variables (sequence, dose, and duration) on the other two. With minor exceptions, the maximal antiproliferative effect in all three cell lines was observed when IFN-gamma and TNF were administered simultaneously, regardless of the doses of each agent and duration of exposure. Exposing the cells to TNF before IFN-gamma resulted in the least inhibition in cell growth. In all three cell lines, the antiproliferative effects of each treatment group were related directly to the duration of exposure. In two of the three cell lines, an intermittent schedule was as effective as a 24-h exposure. No p78 induction was observed in the HCT 116 cell line with IFN-gamma alone, TNF alone, or the combination; p78 was slightly induced in the SKC01 and VACO 9P cell lines with IFN-gamma alone, and was synergistically induced by the combination of TNF and IFN-gamma. Treatment with a neutralizing antibody to IFN-beta did not reverse the antiproliferative effect of any of the three treatment groups in HCT 116 cells. We conclude that the maximum antiproliferative effect in human colon carcinoma can be achieved by the prolonged simultaneous administration of high concentrations of each drug. If clinical toxicity prohibits this schedule, an intermittent schedule of administration may be effective. The mechanism of the synergistic effect is not due to the induction of IFN-beta or the p78 protein.

Cell Division

A direct comparison of biological response modulation and clinical side effects by interferon-beta ser, interferon-gamma, or the combination of interferons beta ser and gamma in humans.

To directly compare clinical side effects and biological response modification, IFN-beta ser, IFN-gamma, or the combination of IFN-beta ser plus IFN-gamma was administered to 21 cancer patients. Each IFN or the combination was given intravenously on days 1, 8, and 15 in varied order. Each IFN and the combination resulted in significant (P less than 0.05) modulation of IFN-induced proteins. IFN-beta ser was more effective than IFN-gamma in enhancing 2-5A synthetase activity (P = 0.001). IFN-gamma was more effective than IFN-beta ser in enhancing serum beta 2 microglobulin expression (P = 0.05) and indoleamine dioxygenase activity, as assessed by decreased serum tryptophan (P = 0.03). The combination enhanced tryptophan catabolism more effectively than IFN-beta ser in a dose-dependent manner (P less than 0.03). IFN-beta ser/IFN-gamma did not potentiate natural killer cells or antibody-dependent cellular toxicity (ADCC). IFN-beta ser/IFN-gamma enhanced monocyte guanylate cyclase activity, as assessed by serum neopterin, more effectively than IFN-gamma alone (P = 0.005). Both IFNs and the combination resulted in increases in HLA class II expression on monocytes. However, no significant difference in the level of induction of HLA DQ and HLA DR expression between IFN-beta ser/IFN-gamma and either IFN-beta ser or IFN-gamma was noted. Although frequency and servity of side effects of IFN-beta ser, IFN-gamma, or the combination were dose related, induction of induced proteins (with exception of influences on tryptophan catabolism) were not a function of dose administered over the 10-fold range. Continued treatment with the combination intravenously three times a week for 4 wk sustained but did not further potentiate, most of the changes in interferon-induced proteins. Thus, IFN-beta ser and IFN-gamma each resulted in effective and essentially equivalent patterns of induction of induced proteins. When combined, however, these IFNs did not result in potentiation of biological response modification in vivo.

2',5'-Oligoadenylate Synthetase

Depressed in vitro T cell responses concomitant with augmented interleukin-2 responses by lymphocytes from cancer patients following in vivo treatment with interleukin-2.

Peripheral blood lymphocytes obtained from cancer patients receiving interleukin-2 (IL-2) on two separate clinical protocols were evaluated for their in vitro responses to IL-2, alloantigens, and PHA. IL-2 in vivo induced enhanced in vitro proliferative responses to IL-2 and diminished in vitro proliferative responses to phytohemagglutinin (PHA) and alloantigens. Alloinduced cytotoxic T cell responses were also depressed following in vivo IL-2. We examined the kinetics of the in vitro proliferative response to PHA and IL-2 and found that while the response of lymphocytes primed in vivo with IL-2 to PHA was depressed at all times during the 2 week in vitro exposure, the response to IL-2 peaked earlier and higher than did the response to IL-2 by lymphocytes obtained prior to IL-2 therapy. These contrasting effects on antigen-induced T cell responses vs. IL-2 induced nonspecific proliferative and cytotoxic responses suggest the importance of dose and timing of IL-2 administration when used to enhance antigen-specific T cell responses or as an immune enhancing agent combined with vaccines.

Cell Division

Effects of combinations of interferon-beta ser and interferon-gamma on interferon-inducible proteins and on the cell cycle.

SKCO 1 human colon carcinoma cells have been shown to be synergistically inhibited in their growth by the combinations of alpha-interferon (IFN-alpha) or beta-interferon (IFN-beta ser) and gamma-interferon (IFN-gamma). To determine if a correlation could be established between this synergistic antiproliferative effect and a synergistic induction in IFN-inducible proteins, or a unique perturbation in the cell cycle, we studied the effects of IFN-beta ser and IFN-gamma, alone and in combination, on 2',5'-oligoadenylate (2-5A) synthetase, indoleamine-2,3-dioxygenase (IDO), a human analogue of the murine Mx protein (p78), and the phases of cell cycle. 2-5A synthetase was maximally induced after a 24-h exposure to both IFN-beta and IFN-gamma. A synergistic enhancement of 2-5A synthetase activity was observed only with low concentrations of each IFN (0.05 ng/ml). IDO activity was induced by IFN-gamma and the combination of IFN-beta ser and IFN-gamma, but not IFN-beta ser alone. The differences in IDO activity between IFN-gamma and the combination, however, were not statistically significant. The p78 protein was induced in a dose-dependent manner by IFN-alpha and IFN-beta ser. IFN-gamma enhanced the expression of p78 induction by IFN-alpha or IFN-beta ser, even at concentrations of IFN-gamma that did not induce the protein when administered as a single agent. The combination of IFN-alpha and IFN-beta ser, which results in an antagonistic antiproliferative effect, also resulted in an antagonistic induction of p78. No changes in the cell cycle were observed following exposure to IFN-beta ser, IFN-gamma, or the combination, and treatment with IFN-gamma did not inhibit the accumulation of cells in G2M caused by colchicine. Thus, the synergistic antiproliferative effect produced by IFN-beta ser and IFN-gamma in SKCO 1 cells could not be correlated with a synergistic enhancement in 2-5A synthetase or IDO activity, or with a perturbation in the cell cycle. In contrast, the combination of IFN-gamma and IFN-alpha or IFN-beta ser synergistically enhanced the expression of p78 protein in these cells.

2',5'-Oligoadenylate Synthetase

Repetitive weekly cycles of interleukin 2: effect of outpatient treatment with a lower dose of interleukin 2 on non-major histocompatibility complex-restricted killer activity.

Fifteen patients with advanced malignancy who had failed conventional therapy were entered into a protocol consisting of 1 inpatient mo of repetitive weekly cycles of interleukin 2 (IL-2) at 3 x 10(6) units/m2/day by constant infusion for the first 4 days of each week. This was followed by IL-2 administered on an outpatient basis at the same schedule but at a dose of 1 x 10(6) units/m2/day for the next 1 to 6 mo. Nine patients had renal carcinoma, four had melanoma, and two had lymphoma. Thirteen patients completed the induction month, and ten patients completed greater than or equal to 1 mo of outpatient therapy. Only one patient had therapy discontinued because of toxicity due to IL-2. No major toxicities occurred during outpatient therapy. After 1 mo of IL-2 at 3 x 10(6) units/m2/day, profound changes similar to those previously documented were seen in peripheral blood lymphocyte (PBL) counts (4.7-fold increase), lymphokine-activated killer activity (16-fold increase), and the percentage of PBL with natural killer-associated markers including a 3.6-fold increase in the percentage of PBL expressing the Leu 19 (NKH-1) marker, a 3.7-fold increase in Leu 11 (FcIgGR), and a 3.0-fold increase in Leu 17 (OKT10). These indicators of IL-2 effect all remained elevated relative to the baseline at the end of 1 and 2 mo of outpatient therapy at the lower dose. However, lymphokine-activated killer activity and Leu 17 percentage were significantly reduced relative to the effect of the higher induction dose. PBL taken from patients while receiving maintenance therapy showed strong and rapid responses to IL-2 in vitro, confirming the in vivo effects of prolonged IL-2 treatment. Nevertheless, there were no complete or partial antitumor responses seen. This study demonstrates that an immunologically active dose of IL-2 can be given long term as outpatient therapy with tolerable toxicity and results in highly IL-2-responsive "primed" lymphokine-activated killer cells.

Adult

Randomized phase II-III trial of combination beta and gamma interferons and etoposide and cisplatin in inoperable non-small cell cancer of the lung.

We observed major responses in two patients with adenocarcinoma of the lung who had received a combination of interferon (IFN)-beta and IFN-gamma, immediately followed by chemotherapy. To verify these observations, we initiated a prospective randomized phase II-III trial of etoposide and cisplatin, with or without IFN-beta and IFN-gamma, in patients with inoperable non-small cell lung cancer. Thirty-seven patients were randomized to receive either two cycles of chemotherapy or 6 weeks of IFN-beta plus IFN-gamma followed by two cycles of chemotherapy. Chemotherapy consisted of 60 mg of cisplatin/m2 on day 1 and 120 mg of etoposide/m2 on days 4, 6, and 8, repeated every 21 days. Patients who were randomized to the IFN plus chemotherapy arm received 200 micrograms of IFN-gamma and 30 x 10(6) U of IFN-beta three times per week for 6 weeks, followed by two cycles of chemotherapy. Three of 18 (17%) eligible patients in the chemotherapy arm and two of 18 (11%) patients in the combination arm had partial responses. All responses occurred while patients were receiving chemotherapy. Median survival was 190 days for the chemotherapy arm and 246 days in the combined modality arm, as estimated from Kaplan-Meier curves (P = .35). We observed no significant difference in subjective toxic effects between the two arms. We observed more hematologic toxicity during chemotherapy on the combined modality arm (P = .02). We conclude that pretreatment with IFN-beta and IFN-gamma does not enhance the efficacy of etoposide and cisplatin in this disease. Although the combined modality arm is relatively well tolerated, it does result in more chemotherapy-associated toxic effects. This study also exemplifies a hybrid phase II-III trial design, which is useful in allowing phase II results to be quickly incorporated into a phase III trial.

Antineoplastic Combined Chemotherapy Protocols

Phase I trial of human lymphoblastoid interferon with whole body hyperthermia in advanced cancer.

Laboratory studies have shown a potentiation of the biological effects of interferons (IFN) by elevated temperatures (39.5-40.5 degrees C). Based on such observations a Phase I clinical trial involving 17 cancer patients was conducted to assess the toxicity and biological effects of combining whole body hyperthermia (WBH) (40.5 degrees C for 75 min) and IFN. The study design incorporated a treatment schedule which allowed comparisons of WBH alone, to IFN administered i.m., to combinations of the two modalities. Human lymphoblastoid IFN was given for 6 days in weeks, 2, 4, and 6. At least 4 patients were entered at each of three IFN dose levels (1 x 10(6) units/m2; 3 x 10(6) units/m2; 10 x 10(6) units/m2). WBH was delivered on day 1 of week 1, day 6 of week 4, and days 4 and 6 of week 6. IFN was administered 1 h prior to WBH. The schedule used allowed for the development of tachyphylaxis to IFN-induced fever. Maximum temperatures were not significantly higher 24 h post-IFN/WBH than after a comparable number of days of human lymphoblastoid IFN alone. There was no statistically significant difference in toxicity assessments, hematological and hepatic blood parameters, serum IFN levels, or biological response modulation (i.e., 2',5'-oligoadenylate synthetase activity; beta 2-microglobulin levels; natural killer cell cytotoxicity, using K562 target cells and Chang cells) 24 h posttreatment between human lymphoblastoid IFN alone or combined modality therapy. No cumulative toxicity was observed in 6 patients receiving maintenance therapy for up to 1 year. Prior preclinical observations, together with the clinical safety reported in this study, encourage further investigation into the interactions between IFNs and hyperthermia.

2',5'-Oligoadenylate Synthetase

A pilot study of short-course, high-dose cytosine arabinoside, etoposide, and cisplatin in refractory, aggressive-histology, non-Hodgkin's lymphomas.

Twenty-three patients with refractory, aggressive-histology, non-Hodgkin's lymphomas were treated with cytosine arabinoside (2.0 g/m2 i.v. every 12 h on days 1 and 2), etoposide (100 mg/m2 i.v. on days 1 and 2), and cisplatin (35 mg/m2 i.v. on days 1 and 2) every 3 weeks. All patients had received one or two prior chemotherapy regimens. Five of 19 (26%) evaluable patients responded, with a median duration of response of 9 weeks (90% confidence interval: 11-48%). One patient with a complete response remains free of disease over 31 months after completing six cycles of therapy. Six transient responses of less than 1-month duration were also observed. Hematological toxicity was significant: 73% of patients experienced grade 4 neutropenia, and 52% experienced grade 4 thrombocytopenia. Twenty patients (87%) underwent dose reductions following their first cycle of therapy for grade 3 or 4 myelosuppression. We conclude that this combination of drugs, when administered by this schedule, has limited antitumor activity; however, administering the regimen with a dose-intense schedule appears warranted.

Adult