Polyinosinic-polycytidylic acid complexed with poly-L-lysine and carboxymethylcellulose in combination with interleukin 2 in patients with cancer: clinical and immunological effects.

We have performed a phase IB study of polyinosinic-polycytidylic acid complexed with poly-L-lysine and carboxymethylcellulose (poly-ICLC) in combination with interleukin 2 (IL-2) in 25 patients with a variety of cancers. Patients received weekly or biweekly poly-ICLC by i.m. injection, at doses ranging from 0.01 to 1.0 mg/m2, for 1 month. This was followed by 2 months of outpatient therapy with biweekly i.m. poly-ICLC in combination with IL-2 (3 x 10(6) units/m2) given i.v. by 24-h continuous infusion twice weekly, using a portable infusion pump. No objective tumor responses were observed. Toxicity was moderate at all poly-ICLC doses tested and increased only slightly following the addition of IL-2. No increases in peripheral blood natural killer (NK) activity were observed after treatment with poly-ICLC alone. However, high dose poly-ICLC (greater than or equal to 0.3 mg/m2) in combination with IL-2 resulted in NK activity greater than that seen using the same dose of IL-2 in combination with lower poly-ICLC doses. Increases in the number and percentage of CD56+ cells were evident only after initiation of IL-2 therapy and were unaffected by the poly-ICLC dose. In the majority of patients, these increases were preferentially associated with the subset of CD56+ cells coexpressing CD8, while the CD56+/CD16+ population was elevated to a lesser extent. Moderate increases in serum neopterin levels and 2',5'-oligoadenylate synthetase activity in peripheral blood mononuclear cells were noted at 72 h following initial treatment with 1.0 mg/m2 poly-ICLC. No induction of alpha or gamma interferon was detected. This study shows that the addition of poly-ICLC to a well tolerated IL-2 regimen can significantly enhance NK activity. Poly-ICLC can be used to enhance IL-2-induced NK lytic activity without increases in the dose and, therefore, the toxicity of IL-2 treatment.

Poly I:C accelerates development of diabetes mellitus in diabetes-prone BB rat.

We developed a new experimental model of accelerated diabetes mellitus in the genetically susceptible diabetes-prone BB rat with the administration of the IFN-alpha inducer poly I:C. With this model, there was both an increased incidence and accelerated onset of insulin-dependent-diabetes in poly I:C-treated animals compared with saline-treated controls. All twelve rats administered poly I:C (5 micrograms/gm body weight 3 times/wk) developed diabetes by 57 days of age (100%) compared with 1 of 27 (3.7%) saline-treated controls. Furthermore, the development of diabetes was accelerated in the poly I:C-treated group (mean age +/- SE at onset 52.8 +/- 0.58 days) compared with saline-treated controls (89.3 +/- 2.4 days, P less than 0.01). Additionally, poly I:C-treated rats had higher mean serum IFN-alpha levels than saline-treated rats at weeks 2 and 3 of treatment (210 vs. 27 and 183 vs. 25 U/ml, respectively, P less than 0.001). Poly I:C treatment of 5 Wistar rats, the parental strain, which is not susceptible to diabetes, did not result in insulitis, diabetes, or hyperglycemia. The histopathologic findings of insulitis and decreased immunoreactive islet insulin in poly I:C-accelerated diabetic BB rats and in BB rats with spontaneous diabetes suggest a similar pathophysiology.

Poly I:C induces development of diabetes mellitus in BB rat.

Polyinosinic polycytidilic acid (poly I:C), an inducer of alpha-interferon, accelerates the development of diabetes in diabetes-prone (DP) BioBreeding (BB) rats. This study investigates the effect of administering poly I:C to a diabetes-resistant (DR) strain of BB rats. We compared the incidence of diabetes, the degree of insulitis, the number of NK cells, helper-inducer cells, cytotoxic-suppressor cells, Ia+ T cells, RT6.1+ T cells, and NK cell bioactivity in DR rats treated with saline and with a 5 micrograms/g body wt (poly-5) dose and a 10 micrograms/g body wt (poly-10) dose of poly I:C. The incidence of diabetes was also compared with that of DP rats receiving poly-5. We found that both doses of poly I:C significantly induce the development of diabetes in the DR BB rat. However, treatment of DR rats with the higher dose induces a greater rate of development of diabetes and earlier onset of diabetes than the lower poly-5 dose. The rate of diabetes development and the mean age of onset were similar in poly-10-treated DR and poly-5-treated DP rats. A significant degree of insulitis occurred in all the poly I:C-treated DR rats, even those not developing diabetes. Peripheral blood NK cell number was greater in poly I:C than in saline-treated rats, after 2 wk of treatment and when killed. The percentage of OX19+ peripheral blood mononuclear cells expressing RT6.1 allotype or Ia antigen were similar in poly I:C- and saline-treated rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Poly I:C induction of alpha-interferon in the diabetes-prone BB and normal Wistar rats. Dose-response relationships.

Although the administration of a fixed dose of the alpha-interferon (alpha-IFN) inducer, polyinosinic polycytidilic acid (poly I:C), accelerates the development of diabetes in DP-BB rats, no reports have characterized the dose-response relationship of poly I:C with serum alpha-IFN levels and the development of diabetes. This study examines the dose-response relationships of poly I:C with the induction of serum alpha-IFN and the development of diabetes in DP-BB and normal Wistar rats. Also tested in this study is the hypothesis that the lack of development of diabetes in poly I:C-treated normal Wistar rats is attributable to a deficient alpha-IFN response. Using poly I:C doses of 0.5, 1.5, 5, and 10 micrograms/g body weight, a direct dose-response relationship was observed in DP-BB rats with the serum alpha-IFN response. Moreover, all doses of poly I:C accelerated the onset of diabetes in BB rats. Serum alpha-IFN levels inversely correlated with time of onset of diabetes (P < 0.01). Also, BB rats with higher levels of serum alpha-IFN were associated with earlier onset of diabetes (P < 0.001). Poly I:C-induced serum alpha-IFN levels were significantly lower in diabetic than in nondiabetic BB rats. In normal Wistar rats, although all doses of poly I:C significantly increased serum alpha-IFN levels, diabetes was not induced. The results of this study indicate that poly I:C administration elevates serum alpha-IFN and accelerates the development of diabetes in BB rats at even very low doses.(ABSTRACT TRUNCATED AT 250 WORDS)

Phase I/IB study of polyadenylic-polyuridylic acid in patients with advanced malignancies: clinical and biologic effects.

The synthetic polynucleotide polyadenylic-polyuridylic acid (polyA:polyU) has shown antitumor activity in murine studies and human breast cancer. PolyA:polyU was evaluated in 25 cancer patients receiving weekly intravenous doses between 3 and 600 mg/m2. PolyA:polyU was well tolerated up to 600 mg/m2, with no doselimiting toxicity (all < grade 3). Side effects included mild elevation in temperature, fatigue, and mild hyperglycemia. No changes outside of the normal range in hematocrit, WBC count, platelet count, total bilirubin, or alkaline phosphatase were observed. Of 25 patients, 18 completed at least one cycle of 6 weeks, and 5 completed two cycles (median 6 weeks). Four patients had stable disease over 11-13 weeks of treatment, and no clinical responses were observed. At 24 h after the first treatment, there were no significant increases in biologic response (beta 2-microglobulin and neopterin in serum, or 2',5'-oligoadenylate synthetase in peripheral blood mononuclear cells). A small increase in beta 2-microglobulin was observed 24 h after the week 3 treatment (1.1-fold, p < 0.01). By the third week of treatment, 2-5A synthetase levels decreased slightly (to 80% of baseline, p < 0.01). No changes in cytokines IL-6, IL-12, tumor necrosis factor (TNF), or IL-2 receptor in serum were detected after 24 h of treatment. Thus, at these doses, polyA:polyU had no marked modulation on biologic responses in vivo, although this preparation significantly induced 2-5A synthetase in peripheral blood mononuclear cells in vitro. PolyA:polyU was well tolerated. An MTD was not reached but was greater than 600 mg/m2 on this weekly schedule.

In vivo radioprotective effect of AcSDKP on canine myelopoiesis.

The tetrapeptide acetyl-N-Ser-Asp-Lys-Pro (AcSDKP) interferes with G1/S-phase progression, and the resulting cell cycle arrest is thought to protect hematopoietic stem cells against injury by cycle-active cytotoxic agents. We investigated the radioprotective effect of AcSDKP in a canine radiation model. Dogs were given total-body irradiation (TBI) at an exposure rate of 10 cGy/min, either without further therapy (control) or with administration of AcSDKP at 0.05-500 micrograms/ kg/24 h beginning before and continuing until after completion of TBI. At 400 cGy of TBI, one of 28 control dogs and one of eight AcSDKP-treated dogs recovered hematopoiesis (p = 0.40). At 300 cGy, seven of 21 control dogs recovered hematopoiesis compared with five of five AcSDKP-treated dogs (p = 0.01). In dogs given 300 cGy and AcSDKP, the granulocyte nadirs were less profound (p = 0.04) and occurred later (p = 0.04) than among controls; platelet kinetics did not differ. These data suggest, therefore, that AcSDKP provides a radioprotective effect in dogs exposed to 300 cGy TBI. Such an effect might be beneficial in recipients of intensive radiation therapy. Conceivably, the effect on hematopoietic recovery could be amplified by growth factor administration after irradiation.

Immunomodulatory effects of interferon-gamma in patients with metastatic malignant melanoma.

Interferon-gamma (IFN-gamma) is a potent monocyte/macrophage activating agent that in animal models exhibits a bell-shaped dose-response curve of immunomodulatory activity and antitumor efficacy. Previous clinical trials of IFN-gamma conducted at the maximal tolerated dose (MTD) have been associated with low response rates that may have been due to failure to treat at an optimal immunomodulatory dose (OID). The objective of this study was to test the hypothesis that optimal immunomodulatory activity of IFN-gamma in patients with metastatic melanoma would be obtained at a dose below the MTD. Groups of five patients each were given daily subcutaneous injections of IFN-gamma at doses of 0.01, 0.1, or 0.25 mg/m2. In vivo immunomodulation was assessed by serial measurement of serum neopterin and by flow cytometry. IFN-gamma doses of 0.1 or 0.25 mg/m2 induced significantly greater immunomodulation of monocyte-associated immune parameters than 0.01 mg/m2. Changes in immunologic parameters included marked elevation of serum neopterin levels, significant increases in monocyte expression of CD64, beta 2-microglobulin, and HLA-ABC, and decreased monocyte expression of CD14. The most dramatic decreases in CD14 expression were observed on monocytes obtained from patients treated at 0.25 mg/m2. The 0.25-mg/m2 dose group had significantly lower white blood cell counts on day 14. No bell-shaped curve of immunologic response was observed over the dosage range tested. Based on the similarity of the immunologic effects at 0.1 and 0.25 mg/m2, treatment at the MTD of IFN-gamma (0.25 mg/m2) represents treatment at the OID for patients with metastatic malignant melanoma.

Loss of interferon antibodies during prolonged continuous interferon-alpha 2a therapy in hairy cell leukemia.

Although highly active in hairy cell leukemia (HCL), interferons (IFN) are not curative in this disease; current data indicate that prolonged IFN therapy will be necessary to control disease in the majority of patients. We previously observed acquired IFN resistance in association with neutralizing IFN-alpha 2a antibodies in small numbers of patients with HCL. This finding suggests that the requisite long-term therapy may be compromised if there is an increasing incidence over time of neutralizing antibodies. We performed a follow-up study of IFN antibodies in our patients receiving continuous IFN therapy. All 16 patients who were previously antibody negative remained so. Surprisingly, all nine patients who previously had non-neutralizing IFN antibodies became antibody negative after a median of 14.5 months. Moreover, 3 of 10 patients who had neutralizing antibodies became antibody negative and five had only non-neutralizing antibodies a median of 10 months from the time neutralizing antibody had first been detected. Only two patients had persisting neutralizing antibodies. Inhibition of neopterin synthesis, inhibition of generation of 2', 5' oligoadenylate synthetase activity, and inability to detect IFN in serum after subcutaneous injection of IFN-alpha 2a was observed only in the one patient tested with neutralizing IFN antibodies confirming that these antibodies have functional significance in vivo. We conclude that, although neutralizing IFN antibodies inhibit the effectiveness of IFN in vivo, these antibodies are produced only transiently during long-term therapy. The long-term effectiveness of this drug will not likely be affected in most patients by neutralizing antibody.