Eradication of disseminated murine leukemia by chemoimmunotherapy with cyclophosphamide and adoptively transferred immune syngeneic Lyt-1+2- lymphocytes.

The phenotype of T cells therapeutically effective in immunotherapy of advanced Friend virus-induced (FBL) leukemia in vivo and cytotoxic to FBL in vitro was determined. Mice bearing disseminated FBL leukemia were successfully treated by a combination of cyclophosphamide and adoptive transfer of syngeneic immune lymphocytes. Therapeutic efficacy was largely dependent on the presence of Lyt-1+2- T cells in the transferred cells, whereas cells cytotoxic to FBL tumor in vitro were derived from the Lyt-1+2+ and Lyt-1-2+ subsets. Thus, the predominate cell required to eradicate tumor in adoptive chemoimmunotherapy was not cytolytic to tumor in vitro. Potentially, the Lyt-1+2- cell may operate in vivo as an amplifier cell rather than by a direct anti-tumor effect. Elimination of the Lyt-1+ population with alpha-Lyt-1 and complement prevented the generation of significant cytotoxic responses during both primary in vitro sensitization to alloantigens and in vitro sensitization of tumour-primed cells. The capacity of Lyt-1+ cell-depleted population to generate cytotoxic responses was partially reconstituted by addition, at the initiation of culture, of interluekin 2, a T cell growth factor derived from Lyt-1+2- cells, which contain the CTL and CTL precursors, were nearly as effective in vitro as unseparated immune cells. If the remaining effector cells (i.e., Lyt-1+2- T cells) function in vivo predominantly as amplifier cells, than the tumour-bearing host must be capable of making a positive contribution to the outcome of therapy.

Augmentation of the anti-tumor therapeutic efficacy of long-term cultured T lymphocytes by in vivo administration of purified interleukin 2.

Spleen cells from C57BL/6 mice immunized in vivo with a syngeneic Friend virus-induced leukemia, FBL-3, were specifically activated by culture for 7 d with FBL-3, then nonspecifically induced to proliferate in vitro for 12 d by addition of supernatants from concanavalin A-stimulated lymphocytes containing interleukin 2 (IL-2). Such long-term cultured T lymphocytes have previously been shown to specifically lyse FBL-3 and to mediate specific adoptive therapy of advanced disseminated FBL-3 when used as an adjunct to cyclophosphamide (CY) in adoptive chemoimmunotherapy. Because the cultured cells are dependent upon IL-2 for proliferation and survival in vitro, their efficacy in vivo is potentially limited by the availability of endogenous IL-2. Thus, the aim of the current study was to determine whether exogenously administered purified IL-2 could augment the in vivo efficacy of long-term cultured T lymphocytes. Purified IL-2 alone or as an adjunct to CY as ineffective in tumor therapy. However, IL-2 was extremely effective in augmenting the efficacy of IL-2-dependent long-term cultured T lymphocytes in adoptive chemoimmunotherapy. The mechanism by which IL-2 functions in vivo is presumably by promoting in vivo growth and/or survival of adoptively transferred cells. This assumption was supported by the findings that IL-2 did not enhance the modest therapeutic efficacy of irradiated long-term cultured cells that were incapable of proliferating in the host and was ineffective in augmenting the in vivo efficacy of noncultured immune cells that are not immediately dependent upon exogenous IL-2 for survival.

Allogeneic marrow transplantation for acute nonlymphoblastic leukemia.

Bone marrow transplantation (BMT) from an HLA-matched sibling donor can cure 15% of end-stage patients with refractory acute leukemia. Failures are largely due to acute or chronic graft-versus-host disease, idiopathic or cytomegalovirus-associated interstitial pneumonitis, veno-occlusive disease of the liver, opportunistic infections, and leukemia relapse. The post-BMT leukemia relapse rate has been reduced from 65% to 20-40% by performing BMT in first complete remission (CR). Overall, about 50% of such patients become long-term tumor-free survivors. Younger patients do far better than older ones. A prospective comparative trial for acute nonlymphoblastic leukemia (ANL) in first CR revealed that BMT was more likely than chemotherapy to be fatal within the first 6 months after induction but that the probability of long-term tumor-free survival thereafter was significantly greater after BMT than after chemotherapy. It is recommended that patients less than 30 years old with ANL should undergo BMT while in first CR, whereas those patients over 30 years old should postpone BMT to the earliest sign of relapse.

Effect of dimethylmyleran on cell-mediated immunity to a tumor allograft.

C57BL/6 mice (H-2b) were inoculated on day 0 with killed Moloney lymphoma cells (LSTRA) of BALB/c origin (H-2d), and their spleen cells were tested for reactivity against LSTRA by the 51Cr-release cytotoxicity assay. Cytotoxic reactivity of cells from ice not treated with drug was maximal by day 6 and disappeared by day 10. Cells from mice given dimethylmyleran (DDM) (12 or 16 mg/kg) on day -1 showed higher levels of cytotoxicity, whereas DMM administered on day +1 had little effect. The effect of DMM on the secondary response was tested and compared with that of cyclophosphamide (CY), 180 mg/kg. Cytotoxicity of cells from mice immunized on days 0 and 10 was maximal on day 15 and then declined. CY administered on day 11 prevented the development of any cytotoxicity and, when given on day 14 in the presence of a detectably strong secondary cytotoxic response, abolished the established response. In contrast, DMM given on day 11 delayed the onset and moderately decreased the peaks of secondary reactivity but had no effect when administered on day 14. These results showed that DMM enhanced a primary response, interfered somewhat with the development of a secondary response, and had no effect on an established secondary cell-mediated response to a tumor allograft. DMM thus was one of the rare agents with antitumor activity and little immunosuppressive action.

Identical-twin (syngeneic) marrow transplantation for hematologic cancers.

The Seattle Marrow Transplant Team treated about 130 patients (age 4-68 yr) for hematologic cancer with supralethal chemoradiotherapy and bone marrow transplantation (BMT) from the normal genetically identical twin. The procedure was well tolerated. The principal problem was tumor resistance. Nevertheless, BMT for acute leukemia in relapse still cured about 20% of the patients. Moreover, BMT performed while in complete remission cured about 50% of patients with acute lymphocytic leukemia or acute nonlymphocytic leukemia. Sixteen patients received transplantation in the chronic phase of Ph1+ chronic granulocytic leukemia (CGL). All showed disappearance of all Ph1+ cells. Two died of pneumonitis. Of the 14 who are alive, 3 continue to have CGL 37-76 months after BMT and 11 remain in complete hematologic and cytogenetic remission without any Ph1+ metaphases at 31-108 months (median = 68) after BMT. Thus the Ph1-positive clone can be ablated and blast crisis prevented. BMT in the accelerated or blastic phase was far less effective. Syngeneic BMT also benefited or cured patients with lymphoma, hairy-cell leukemia, and multiple myeloma. Therefore, BMT should be considered for every patient who has a hematologic cancer and an identical twin.

Allogeneic marrow transplantation for chronic granulocytic leukemia.

A retrospective analysis is presented of results obtained with allogeneic bone marrow transplantation (BMT) in three phases of Philadelphia chromosome-positive chronic granulocytic leukemia. At BMT, 23 patients were in blastic phase (BP), 33 were in accelerated phase (AP), and 45 were in chronic phase (CP). With a follow-up time of 1-8 years after BMT, the probability of long-term survival was 14, 10, and 58%, respectively, for patients transplanted in BP, AP, or CP. The probability of cytogenetic relapse with or without clinical hematologic relapse at 3 years after BMT was 80, 38, and 31%, respectively, for patients transplanted in BP, AP, or CP. Splenectomy did not influence posttransplant survival. Given the dismal prognosis on conventional therapy, patients younger than 50 in BP or AP should be considered for BMT. For the patient in CP, BMT offers the possibility of cure but with a significant risk of early death. Patients under 40 who fully understand the risks and potential benefits of BMT should be offered BMT early in CP before any change to AP occurs.

Use of dimethylmyleran in adoptive chemoimmunotherapy of two murine leukemias.

Dimethylmyleran (DMM) is an antitumor agent that has minimal effects on immunity. In a study of its usefulness in adoptive chemoimmunotherapy, C57BL/6 mice inoculated on day 0 with C57BL/6 Friend virus-induced leukemia (FBL-3) were treated on day 5 with 12 mg DMM/kg [less than LD10 (lethal dose for 10% of mice)] plus C5BL/6 spleen cells. All untreated mice died, with a median survival time (MST) of 17 days. DMM alone or with nonimmune cells prolonged survival to day 20, and 3/53 mice survived beyond day 60. By contrast, 12/25 mice treated with DMM plus cells immune to FBL-3 were cured. Similar results were obtained in C57BL/6 mice with syngeneic Rauscher virus-induced leukemia (RBL-5). Untreated mice died, with an MST of 14 days. DMM alone or with nonimmune cells prolonged the MST to 21 and 26 days, respectively, and 3/26 and 6/28 mice were long-term survivors. However, 13/28 mice were cured by DMM plus cells immune to antigenically related FBL-3. Lethal irradiation of cells immune to FBL-3 abolished their efficacy. Finally, in contrast to the efficacy of sublethal DMM plus immune cells, an LD100 of DMM (20 mg/kg) plus hematopoietic reconstitution with nonimmune syngeneic cells was not effective against FBL-3 OR RBL-5. The results emphasized the critical role of immune cells in chemoimmunotherapy even when the drug used is nonimmunosuppressive.

Chemoimmunotherapy of a Friend leukemia with cells secondarily sensitized in vitro: effect of culture duration on therapeutic efficacy.

Although in vivo-primed cells are known to be rendered more effective in adoptive tumor therapy by secondary sensitization in vitro, they were tested only at the time of maximum in vitro cytolytic reactivity. Since the requirements for in vitro cytotoxicity and tumor therapy differ, the present study was designed to evaluate and compare the influence of culture duration on these two effector functions. Spleen cells from inbred C57BL/6 mice primed in vivo with the Friend virus-induced leukemia FBL-3 were secondarily sensitized in vitro by culture with tumor and tested for cytotoxicity in vitro in a 4-hour 51Cr release assay and for therapeutic efficacy in vivo against established tumor. In vivo-primed cells tested directly without prior culture were effective in therapy but were not cytotoxic in vitro. Culture of primed cells for 3 days rendered them cytotoxic as measured in vitro. This cytotoxicity increased through day 5, then it plateaued. Cultured duration modified the in vivo efficacy of primed cells differently. Cells cultured for 3 days with secondary sensitization by tumor became more effective in tumor therapy than noncultured primed cells. Increasing the duration of in vitro sensitization from 3 to 5 days did not enhance in vivo therapeutic efficacy, despite a concurrent increase in in vitro cytotoxicity. However, further lengthening of the culture duration to 7 days rendered cells more effective in vivo. These discrepancies presumably reflect different effector cell requirements and/or regulation operative for tumor lysis during a short-term in vitro assay and for tumor eradication following adoptive transfer of immune cells in vivo.

Randomized study of the duration of treatment with interferon alfa-2B in patients with hairy cell leukemia.

Several previous studies have demonstrated that both partially purified and recombinant alpha-interferons (alpha-IFNs) have high response rates in advanced hairy cell leukemia. However, the optimal dose and duration of therapy have not yet been defined. In this study, 90 patients were randomized after 12 months of IFN alfa-2b therapy with a standard dose of 2 X 10(6) U/m2 sc three times weekly to either no further therapy or an additional 6 months of therapy (18 mo total). There was no significant difference in the peripheral blood cell counts between the two groups (when analyzed) dating from the end of IFN therapy rather than from the time of randomization. Eighteen evaluable patients relapsed and were re-treated with IFN: 11 in the no-further-therapy group and 7 in the treated group. No patient was resistant to re-treatment with IFN. There was a significantly greater incidence of fatigue in the treated group (44% vs. 21%; P = .02) during the first 6 postrandomization months. We conclude that the duration of IFN therapy does not influence the clinical course after therapy is discontinued, but responses are maintained while patients receive therapy. However, because of a high incidence of fatigue with prolonged therapy and the ability to reinduce a second response, we recommend that IFN therapy be discontinued after 12 months in asymptomatic patients.

Suppression of secondary cellular immunity to a tumor allograft by cyclophosphamide and 1,3-bis(2-chloroethyl)-1-nitrosourea.

C57BL/6 mice (H-2b) were immunized with lethally x-irradiated Moloney virus-induced lymphoma cells of BALB/c origin (H-2d) on Days 0 and 10 and received rug on Days 11 and 14. Their spleen cells were then tested for reactivity against Moloney virus-induced lymphoma of BALB/c origin by the 51Cr-release cytotoxicity assay. In non-drug-treated mice the secondary cytotoxic response was maximal on Days 14 to 15, declined rapidley, and recurred after Day 21. The cytotoxic effector cells were shown to be theta-bearing T-lymphocytes. Cyclophosphamide (CY), 180 mg/kg, given on Day 11, totally prevented the development of a cytotoxic response and when given on Day 14 abolished the response already established. CY, 48 mg/kg, as well as 1,3-bis(2-chloroethyl)-1-nitrosourea 33 mg/kg, were almost as suppressive. Immune mice given CY on Day 14 and reimmunized on Day 36 exhibited a normal tertiary response. Mice similarly immunized on Days 1 and 10 and given drugs on Day 14 were challenged on Day 15 with up to 3.5 x 10-8 viable Moloney virus-induced lymphoma cells of BALB/c origin. Despite H-2 incompatibility, all nonimmune control mice developed ascites and died, whereas all mice immunized but not given drug failed to develop ascites. By contrast, 17 of 34 immunized mice given CY, 180 mg/kg, and 7 of 34 given 1,3-bis(2-chloroethyl)-1-nitrosourea developed ascites. The ascites eventually regressed. THE RESULTS SHOW THAT CY and 1,3-bis(2-chloroethyl)-1-nitrosourea can suppress a secondary cellular immune response as measured by the T-cell-mediated 51Cr-release cytotoxicity assay in vitro and by viable tumor challenge in vivo.

Adoptive therapy of established syngeneic leukemia by cells primarily sensitized in vitro.

The aim of the current studies was to determine whether cells primarily sensitized in vitro are effective in adoptive therapy of established tumors. Spleen cells from normal BALB/c mice were cultured for 5 days at variable responder:stimulator ratios with an X-irradiated syngeneic Moloney virus-induced leukemia (LSTRA), denoted as BALB/c.(LSTRA)x, or with X-irradiated normal BALB/c spleen cells, denoted as BALB/c. (BALB/C)x, and tested for ability to eradicate an established lethal inoculum of LSTRA in adaptive chemoimmunotherapy. BALB/c mice inoculated with 2 X 10(3) LSTRA i.p. on Day 0 were treated on Day 5 with cyclophosphamide (180 mg/kg) plus 1 X 10(7) cultured cells. Treatment with cyclophosphamide alone cured only 3% of mice. As an adjunct to cyclophosphamide, therapy with BALB/c.(BALB/c)x cultured at responder:stimulator ratios of 8:1, 32:1, and 128:1 cured 29%, 37%, and 33% of mice, respectively; and BALB/c.(LSTRA)x cultured at the same responder:stimulator ratios cured 54, 83, and 29% of mice, respectively. Furthermore, the therapeutic efficacy of BALB/c.(LSTRA)x was abrogated by treatment with anti-Thy 1.2 + complement. Thus, culture of normal lymphoid cells with tumor at optimal responder:stimulator ratios substantially enhanced their ability to eradicate established tumor, and the enhanced therapeutic efficacy was mediated by a T-cell generated during culture. The specificity of primary in vitro sensitization in generating cells effective in the therapy of established tumors was confirmed by treating BALB/CH-2d X C57BL/6H-2b F1 (hereafter called B6F1) mice bearing either LSTRAH-2d or an antigenically distinct chemically induced leukemia, EL-4(G-)H-2b, with CB6F1 spleen cells sensitized in vitro to either of the parental tumors.

Detection of early and delayed antitumor effects following curative adoptive chemoimmunotherapy of established leukemia.

Advanced disseminated leukemia can be successfully eradicated by treatment with a combination of noncurative nonlethal chemotherapy plus adoptively transferred immune cells. The time course of tumor elimination following such therapy was examined by bioassay for tumor of peripheral blood and spleen cells from treated mice. Curative treatment with adoptive chemoimmunotherapy did not immediately eliminate all leukemia. Bioassay of cells from treated mice, rather, demonstrated that, following the initial tumor lysis mediated by the chemotherapy and immune cells, a period of tumor regrowth lasting several weeks preceded ultimate tumor eradication. This transient tumor regrowth detectable by bioassay never became clinically evident in the treated mice. However, immunosuppression of mice two weeks after treatment with adoptive chemoimmunotherapy resulted in recurrence of lethal tumor. The results suggest that tumor elimination following curative adoptive chemoimmunotherapy is biphasic and that the efficacy of therapy may be subject to positive and/or negative influences over a prolonged time period.

Phase Ib trial of pentoxifylline and ciprofloxacin in patients treated with interleukin-2 and lymphokine-activated killer cell therapy for metastatic renal cell carcinoma.

The dose of interleukin 2 (IL-2) which can be administered to cancer patients is limited largely by a capillary leak syndrome. Pentoxifylline (PTX) is a methylxanthine which reduces IL-2 toxicity in animals. Ciprofloxacin (Cipro) modifies the metabolism of methylxanthines and, when coadministered with PTX, increases levels of PTX and certain of its metabolites. We conducted a phase Ib trial in patients receiving IL-2 and lymphokine-activated killer cell (LAK) cell therapy for metastatic renal cell carcinoma to identify the maximum tolerated dose of PTX which could be coadministered with Cipro in this setting. Eighteen patients received IL-2 (Roche) by continuous infusion at 6 x 10(6) units/m2/day on days 1-5 and underwent leukapheresis on days 7-9. LAK cells were infused on days 12-14. IL-2 was administered at 2 x 10(6) units/m2/day on days 10-20. Cohorts of patients received PTX at 2.5 (n = 3), 3.1 (n = 6), 3.9 (n = 6), and 4.9 (n = 3) mg/kg by 30 min i.v. infusion every 4 h on days 0-5 and 10-20 and Cipro (500 mg p.o. every 12 h) on days 1-5 and 10-20. Toxicity was compared with that observed in 33 historical control patients who received 37 cycles of an identical regimen of IL-2/LAK without PTX/Cipro. PTX at 2.5-3.9 mg/kg and Cipro were well tolerated. The maximum tolerated dose of PTX was 3.9 mg/kg. Dose-limiting emesis (n = 1) and atrial fibrillation (n = 2) occurred at 4.9 mg/kg and were reversible. Two complete, one partial and one minor, responses were observed. Patients treated with 3.9 mg/kg PTX received 95.0% of the planned dose of IL-2 as compared to 72.8% in the control patients (P < 0.025), primarily due to a lower incidence of azotemia and metabolic acidosis in PTX/Cipro recipients than had been seen in the historical control patients. The results of this study demonstrate that PTX/Cipro can be administered to patients receiving IL-2/LAK without apparent loss of therapeutic efficacy. Moreover, PTX/Cipro recipients exhibited less toxicity than historical controls. Therefore, treatment with PTX/Cipro may allow delivery of higher doses of IL-2, which might induce more responses in IL-2-responsive tumors and regression of tumors unresponsive to conventional doses of IL-2.

Lymphokine-activated killer function following autologous bone marrow transplantation for refractory hematological malignancies.

Disease recurrence remains the major factor which limits the success of autologous bone marrow transplantation (ABMT) for refractory hematological malignancies. The administration of interleukin 2 (IL2) with or without ex vivo generated lymphokine-activated killer (LAK) cells represents a potential approach to eradicating residual disease after ABMT. However, since LAK precursor activity is radiosensitive, high dose chemoradiotherapy may abrogate LAK function and preclude clinical responsiveness to IL2 after ABMT. Furthermore, since lymphocyte subsets which mediate LAK activity may recover at different rates after ABMT, LAK cells may be phenotypically and/or functionally altered after ABMT. To determine whether IL2 responsive LAK precursor cells are present in the circulation after ABMT, peripheral blood mononuclear cells (PBMC) from 21 patients with acute leukemia or lymphoma were tested for IL2-inducible LAK activity 17-83 days after ABMT. Cells were cultured with IL2 (1000-2000 units/ml) for 4 or 5 days and then tested for cytolytic activity and/or cell phenotype. LAK activity against the Daudi cell line was detected in every PBMC sample from every patient at every time point tested. The Raji cell line and a fresh allogeneic ovarian carcinoma were also lysed by LAK cells generated after ABMT. In the subgroup of patients transplanted for non-Hodgkin's lymphoma, LAK precursor activity appeared comparable to that of healthy controls. Culture with IL2 resulted in increased mean IL2 receptor expression in lymphocytes from patients after ABMT (3.1-9.9%) and from healthy controls (3.1-12.0%). After culture with IL2, the percentage of cells bearing the natural killer cell-associated Leu-19 determinant was significantly higher in patient PBMC than in normal control PBMC (28.3 versus 8.7%). Positive and negative cell selection by fluorescence sorting after culture with IL2 revealed that most of the LAK activity after ABMT was mediated by the Leu-19+ cells. Although CD5+ T-cells were devoid of LAK activity, a subset LAK effectors was CD8+. Thus, LAK activity is rapidly reconstituted after ABMT and is mediated by cells phenotypically similar to those in normal controls. These results support the feasibility of IL2 +/- LAK as consolidative immunotherapy after ABMT.

Enhancement by interleukin 4 of interleukin 2- or antibody-induced proliferation of lymphocytes from interleukin 2-treated cancer patients.

Systemic interleukin 2 (IL-2) and IL-2-activated lymphocytes have induced tumor regression in some cancer patients. The IL-2-activated cells have usually been generated by obtaining peripheral blood mononuclear cells (PBMC) from cancer patients shortly after systemic IL-2 therapy and culturing them with IL-2 in vitro. In an effort to augment the ex vivo generation of such cells preactivated in vivo, we examined the proliferative responses of PBMC from IL-2-treated cancer patients to several proliferative signals including IL-2, interleukin 4 (IL-4), and mitogenic antibodies to CD3 and CD28. Although much is known about the response of normal PBMC to these signals, the possibility was considered that the response of lymphocytes preactivated by IL-2 in vivo might differ from that of normal PBMC. Accordingly, PBMC obtained from ten normal, healthy controls and from 17 patients with advanced cancer 1 to 3 days after systemic IL-2 therapy were cultured for 4 days with IL-4 (1000 units/ml) and/or IL-2 (10 units/ml or 1000 units/ml) or with combinations of IL-4 and anti-CD3 +/- anti-CD28, and they were then tested for proliferation by [3H]thymidine incorporation. IL-4 failed to induce proliferation of normal PBMC and inhibited IL-2-induced proliferation, whereas IL-4 alone induced proliferation in PBMC from five of 11 IL-2-treated patients and did not inhibit but augmented the proliferation induced by IL-2 (10 units/ml and 1000 units/ml) in PBMC from six of nine patients and five of 11 patients, respectively. Anti-CD3 induced proliferation in PBMC from eight of nine patients, and the proliferation was consistently augmented by coculture with anti-CD28. Finally, IL-4 significantly augmented the proliferative responses of PBMC from IL-2-treated patients to anti-CD3, as well as to the combination of anti-CD3 and anti-CD28. Thus, in PBMC from IL-2-treated cancer patients, IL-4 enhanced the in vitro proliferation induced by IL-2 or by anti-CD3 +/- anti-CD28. The results suggest that IL-4 and/or mitogenic antibodies may be useful in augmenting the ex vivo generation of lymphocytes for clinical adoptive immunotherapy.

Influence of schedule of interleukin 2 administration on therapy with interleukin 2 and lymphokine activated killer cells.

The purpose of this study was to compare the toxicity, immunomodulatory changes, and antitumor efficacy of interleukin 2 (IL-2) and lymphokine activated killer (LAK) cell therapy with two durations of IL-2 infusion. Patients with progressive melanoma, non-Hodgkin's lymphoma, renal carcinoma, or colon carcinoma received IL-2 at 3 X 10(6) units/m2/day on days 1-5 and 13-17, either by bolus injection every 8 h (q8h) or by continuous i.v. (CIV) administration. Peripheral blood mononuclear cells were harvested by leukapheresis on days 8, 9, and 10, were incubated in vitro for 5 days for generation of LAK cells, and were infused on days 13, 14, and 15. The first 11 patients were treated with IL-2 q8h, and the subsequent 13 patients were treated by CIV infusion. Toxicity consisted primarily of fever, chills, emesis, diarrhea, weight gain, and edema but did not require intensive care unit support and did not differ significantly between treatment groups. IL-2-induced lymphocytosis on day 8 was higher with CIV than with q8h administration with a mean lymphocyte count/microliter of 5610 +/- 700 (SE) versus 3300 +/- 500. Immunomodulatory changes observed on days 8 and 20 were also greater with CIV IL-2 and included an increase in peripheral blood mononuclear cell IL-2 receptor expression as well as a marked rise in the number of Leu-11+ and Leu-19+ peripheral blood mononuclear cells. The total leukapheresis yield per patient and total number of LAK cells infused per patient were higher with CIV than q8h administration, with 49.8 +/- 4.9 X 10(9) versus 39.4 +/- 5.4 X 10(9) and 42.6 +/- 5.0 X 10(9) versus 34.0 +/- 5.4 X 10(9), respectively. The cells infused displayed phenotypic evidence of activation and exhibited marked lytic reactivity to Daudi, Raji, and HT-144 targets. One complete and one minimal response were observed in 2 of 8 patients with metastatic renal cell carcinoma who received CIV IL-2 and LAK cells. The results show that IL-2 is more biologically active by CIV than q8h administration, as demonstrated by greater rebound lymphocytosis, LAK cell yield, and in vivo immunostimulation.

Induction of lymphokine-activated killer activity by interleukin 4 in human lymphocytes preactivated by interleukin 2 in vivo or in vitro.

In an attempt to augment the generation of human cytotoxic effector cells for potential cancer therapy with interleukin 2 (IL2) and lymphokine-activated killer (LAK) cells, the effect of interleukin 4 (IL4) on LAK cell induction was studied. In normal human peripheral blood lymphocytes (PBL), IL4 does not induce LAK activity and inhibits LAK induction by IL2. However, since lymphocyte activation, such as with antigen or mitogen, can render them responsive to IL4, the ability of IL4 to induce LAK activity in lymphocytes preactivated in vivo or in vitro with IL2 was investigated. PBL obtained from 12 patients with advanced cancer 1 to 3 days after IL2 therapy and from eight healthy control subjects were cultured 4 to 5 days with or without IL4 and/or IL2 and then tested for LAK activity as assessed by lysis of Daudi in a 4-h 51Cr release assay. In normal PBL, IL4 failed to induce LAK activity and consistently inhibited LAK induction by a suboptimal concentration of IL2 (10 units/ml). By contrast, IL4 induced LAK activity in PBL from seven of twelve IL2-treated patients and augmented LAK induction by the suboptimal IL2 in PBL from five of twelve IL2-treated patients. With an optimal LAK-inducing concentration of IL2 (1000 units/ml), IL4 less consistently inhibited LAK induction in normal PBL and had a variable effect upon LAK induction in PBL from IL2-treated patients. IL4 induced LAK activity in PBL obtained from a cancer patient after, but not before, systemic IL2 therapy. Similarly, IL4 induced LAK activity in normal PBL only after they had been preincubated with IL2. Thus, IL4 induces LAK activity in lymphocytes preactivated by IL2 in vivo or in vitro. Fluorescence-activated cell sorting revealed that the LAK activity, whether induced by IL4 or by IL2, was mediated largely by non-T (CD5-) natural killer-like (CD56+) cells. The results suggest a regulatory relationship between IL2 and IL4 in the induction and/or maintenance of LAK activity, which might be exploited to augment the generation of cytotoxic cells for lymphokine-mediated immunotherapy of human cancer.

Recombinant interleukin 2 toxicity, pharmacokinetics, and immunomodulatory effects in a phase I trial.

Twenty-two patients with refractory malignancies were treated with four escalating weekly doses of recombinant interleukin 2 (IL2), given either i.v. by 2- or 24-h infusion, or s.c. A 1-wk washout period between each dose of IL2 was provided for the evaluation for pharmacokinetic and immunomodulatory effects. The maximum i.v. dose was 30 X 10(6) units; the dose-limiting toxicities were fever, flu-like symptoms, and hypotension. The maximum s.c. dose was 3 X 10(6) because of volume limitations with s.c. injection. No tumor regression was seen. During infusions of 3 X 10(6) units over 2 h or 24 h, serum IL2 levels greater than or equal to 223 units/ml or 16 units/ml were maintained, respectively; with s.c. injection of 3 X 10(6) units, levels greater than 20 units/ml were maintained for 9 h. Marked lymphopenia was observed 24 h after the initiation of IL2 doses which was completely reversible when measured prior to the next dose. The lymphopenia was nonselective; T- and B-lymphocytes decreased in an IL2 dose-dependent manner, without consistent change in the OKT4:OKT8 ratio. No change was detected in monocyte expression of HLA-Dr or T-cell expression of the IL2 receptor. The in vitro generation of lymphokine-activated killer cytotoxicity decreased sharply and transiently shortly after i.v. doses. Mitogen responsiveness, delayed-type hypersensitivity, natural killer cytotoxicity, and mixed-lymphocyte reactivity were unchanged or decreased transiently shortly after IL2 doses. These studies help define the bioavailability of IL2 by i.v. or s.c. routes, and they will aid in the design of studies utilizing daily doses of IL2.

Subcutaneous granulocyte-macrophage colony-stimulating factor in patients with myelodysplastic syndrome: toxicity, pharmacokinetics, and hematological effects.

The toxicity, pharmacokinetics, and hematologic effects of granulocyte-macrophage colony-stimulating (GM-CSF) were studied in a phase I/II trial of 16 patients with myelodysplastic syndrome (MDS). The GM-CSF was administered subcutaneously (SC) daily so as to achieve prolonged blood levels and to establish an outpatient treatment regimen. Four dose levels were administered for ten days: 0.3 microgram/kg/d (three patients), 1.0 microgram/kg/d (three), 3.0 micrograms/kg/d (four), and 10.0 micrograms/kg/d (six). The most common toxicities were fever and a flu-like syndrome, which were dose-dependent. The maximum-tolerated dose was 10.0 micrograms/kg/d, which induced severe rigors (two patients), fever greater than 40 degrees C (one), severe bronchospasm (one), and WBC 60,000 (one). In one patient, refractory anemia with excess blasts in transformation (RAEB-T) progressed to acute nonlymphocytic leukemia after two doses of GM-CSF, and the patient died of leukemia that did not respond to chemotherapy. After doses of 3.0 and 10.0 micrograms/kg, serum GM-CSF levels peaked at 3.8 to 6.3 hours, and persisted for 14 and 24 hours, respectively. Circulating granulocytes (neutrophils and bands) increased in a dose-dependent manner, as 11 of 13 patients who received greater than or equal to 1.0 microgram/kg/d responded with a two- to 194-fold increase. Although the neutrophils usually returned to pretreatment levels shortly after stopping GM-CSF, two patients continue to exhibit an elevation of neutrophils for 6 months. Dose-related increases in circulating monocytes and eosinophils were also noted. Transient increases in platelet and reticulocyte counts were observed in two and three patients, respectively. Five of the 16 patients later received maintenance GM-CSF at 3 micrograms/kg/d for 2 to 9 weeks. All showed a dramatic increase in neutrophils after 2 weeks. Thereafter, despite continued therapy, the neutrophil count in four patients declined markedly. In conclusion, GM-CSF is well tolerated by the SC route and induces striking, but usually temporary, improvement in the neutropenia of MDS. Larger prospective phase III trials will determine the duration of hematologic responses and the impact on infection, morbidity, and mortality.

Alpha-2 interferon therapy of hairy-cell leukemia: a multicenter study of 64 patients.

Sixty-four patients with hairy-cell leukemia (HCL) (61 had undergone prior splenectomy) were treated with alpha-2 interferon (Intron A, Schering Corp, Kenilworth, NJ) subcutaneously three times per week at a dosage of 2 X 10(6) U/m2. Three patients (5%) demonstrated a complete response (CR) with apparent eradication of hairy cells from the bone marrow, 45 patients (70%) showed a partial response (PR) defined as normalization of all three blood counts associated with decreased involvement in the bone marrow, and nine patients (14%) showed a minor response that included improvement in at least one blood count. Three patients had no response, three patients died before completing 1 month of therapy, and one patient refused further therapy after 1 month of therapy. The median platelet count returned to normal by the second month of treatment. The median hemoglobin returned to greater than 12 mg/dL by the fourth month of treatment, and the median granulocyte count to greater than 1,500/mu by the fifth month of treatment. Bone marrow biopsy analysis during interferon therapy demonstrated a decrease in median hairy-cell index by more than half. Transfusion of both RBCs and platelets were decreased within 4 months of initiating treatment. Serious infections, which averaged four per month in 16 of the 64 patients before interferon therapy, were rarely observed after the first month of treatment. Treatment-induced toxicity was mild, consisting primarily of influenza-like symptoms, fatigue, and minor skin disorders. Alpha-2 interferon therapy is highly effective in reversing the course of progressive HCL and should be considered the treatment of choice for a minimum of 12 months in patients who have progressive disease post-splenectomy.