Analysis of morbidity and mortality in 60 patients with peritoneal carcinomatosis treated by cytoreductive surgery and heated intraoperative intraperitoneal chemotherapy.

BACKGROUND: Peritoneal carcinoma has been regarded as a uniformly lethal clinical entity. A treatment plan combining cytoreductive surgery and heated intraoperative intraperitoneal chemotherapy (HIIC) was devised and tested to treat such patients. The purpose of this study was to evaluate the morbidity and mortality associated with this treatment approach. METHODS: Sixty patients with peritoneal carcinomatosis from adenocarcinoma of the colon or appendix were included in the study. Extensive cytoreductive surgery was combined with heated intraperitoneal mitomycin in an intraoperative lavage technique followed by one cycle of early postoperative intraperitoneal 5-fluorouracil. Eleven clinical variables were selected and statistically correlated with morbidity and mortality. RESULTS: Twenty-five complications occurred in 21 patients (morbidity = 35%). Morbidity related to gastrointestinal function included anastomotic leak (n=6), bowel perforations (n=5), bile leak (n=3), and pancreatitis (n=2). Four patients presented with severe hematologic toxicity (Grade 3 or 4). There were three cases of postoperative bleeding, one case of abdominal wound dehiscence, and one case of pulmonary embolism. Morbidity was significantly associated with three clinical factors: male sex, high intraabdominal temperature during HIIC, and duration of the surgical procedure. Enteral complications (bowel fistula and anastomotic leak) occurred in patients with a significantly higher number of peritonectomy procedures and a significantly longer operation. Three patients died within 8 weeks after the procedure (mortality = 5%). Mortality was significantly associated with age and intraabdominal temperature. CONCLUSIONS: Cytoreductive surgery combined with HIIC is associated with a 35% morbidity rate and a 5% mortality rate. Extensive surgery (duration and number of peritonectomy procedures) and high intraabdominal temperature represent the major risk factors for postoperative morbidity and mortality of patients treated with this new therapeutic approach.

Evolving strategies for the treatment of adenocarcinoma of the pancreas. A review.

Adenocarcinoma of the pancreas has an incidence of only 0.01%, yet is the fourth leading cause of cancer death for American men and women. Despite this dismal outlook, new strategies for staging and therapy for pancreatic cancer have emerged over the last few years. Laparoscopy with cytologic evaluation of peritoneal washings, and more recently, although still investigational, endoscopic and intracorporeal ultrasonography have provided more detailed staging information. The result of improved staging is earlier, more accurate selection of treatment most appropriate for stage of disease. For those patients with clinically localized disease, laparotomy with an attempt at resection is indicated, particularly with the recent trend in declining morbidity and operative mortality the recent trend in declining morbidity and operative mortality associated with pancreatectomy. With clinically unresectable disease, patients may potentially be spared the morbidity of laparotomy. Advances in therapeutic endoscopic and percutaneous manipulation of the obstructed biliary tree have provided an alternative to surgery and improved quality of life for patients with abbreviated life spans. Gastroduodenal obstruction has traditionally been managed by laparotomy, although with improved technology and surgical skill, a laparoscopic approach may become standard. Because even at presentation pancreatic cancer is rarely a localized process but is a disseminated disease, surgery alone is unlikely to increase survival rates in the absence of adjuvant therapies. Present and future strategies for treatment include the addition of neoadjuvant regimens and adjuvant modalities including intraoperative radiation, photodynamic therapy, intraperitoneal therapies, and pancreatic and splanchnic perfusion. Clearly, the greatest strides in treatment of pancreatic cancer will come with development of new agents with significantly greater antitumor efficacy.

Randomized comparison of high-dose and low-dose intravenous interleukin-2 for the therapy of metastatic renal cell carcinoma: an interim report.

PURPOSE: A randomized prospective study was performed to compare the efficacy and toxicity of high-dose intravenous bolus interleukin-2 (IL-2) and a lower-dose intravenous bolus regimen for the treatment of metastatic renal cell carcinoma (RCC). PATIENTS AND METHODS: Between March 1991 and April 1993, 125 patients with metastatic RCC were randomized to receive IL-2 by intravenous bolus every 8 hours at either 720,000 IU/kg (high-dose) or 72,000 IU/kg (low-dose) to the maximum-tolerated number of doses (or a maximum of 15 doses). After approximately 7 to 10 days, both treatment groups were re-treated with a second identical cycle of therapy. Those patients who were stable or responding to treatment 5 to 6 weeks later went on to receive re-treatment with another course (two cycles) of therapy. Response rates and toxicity were determined for the two treatment arms. RESULTS: One hundred twenty-five patients received a total of 208 courses of therapy. Sixty patients were randomized to receive low-dose, and 65 to receive high-dose IL-2. There were no treatment-related deaths in either arm. There was a greater incidence of grade III or IV thrombocytopenia, malaise, and hypotension in patients who received high-dose IL-2, while patients who received low-dose IL-2 had significantly more infections. Three percent of treatment courses with low-dose IL-2 required vasopressor support, compared with 52% of courses with high-dose IL-2. Patients who received low-dose IL-2 had a 7% complete response (CR) and an 8% partial response (PR) rate, and patients who received high-dose IL-2 had a 3% CR and a 17% PR rate. CONCLUSION: Low-dose intravenous bolus IL-2 represents an effective regimen for the treatment of metastatic RCC, with preliminary results comparable to those observed with high-dose IL-2. Low-dose IL-2 can be administered with significantly fewer complications, reduced use of vasopressor support, and fewer admissions to an intensive care unit (ICU).

Postoperative complications in patients receiving suramin therapy.

BACKGROUND: Suramin is an antiparasitic agent that is currently being evaluated for antineoplastic activity. Documented toxicities of suramin include adrenal and renal insufficiency, coagulation factor abnormalities, immunosuppression, and polyneuropathy. These adverse effects have potential for contributing to postoperative morbidity in surgical patients. Because no experience with suramin has been reported in the surgical literature, this 5-year retrospective review of postoperative complications in patients receiving suramin was performed. METHODS: From a review of 171 charts, 14 patients were identified who had undergone a major surgical procedure either while receiving intravenous suramin or within 1 year after its administration. Primary diagnoses included prostate cancer (six), lymphoma (four), ovarian cancer (two), colon cancer (one), and glioblastoma (one). All patients received replacement dose hydrocortisone at the initiation of suramin therapy and thereafter. RESULTS: Eighteen major surgical procedures were performed with 18 complications occurring in five patients. The predominant complications encountered were hemorrhage (five), impaired wound healing (three), and bowel dysmotility (two). A highly significant relationship existed between the incidence of complications and interval from completion of suramin therapy to the time of operation (p < 0.0005), with 17 of the 18 morbidities occurring within the first month. The length of operation (p < 0.05) and amount of blood transfused during the procedure were related to postoperative morbidity (p < 0.05). No other factors evaluated were correlated to complications. CONCLUSIONS: This experience suggests the avoidance of elective procedures during the first month after suramin therapy and a heightened awareness of the potential for bleeding and wound healing problems in patients receiving suramin who do require an emergent procedure.

Phase I trial of recombinant human macrophage colony-stimulating factor administered by continuous intravenous infusion in patients with metastatic cancer.

BACKGROUND: Macrophage colony-stimulating factor is a bone marrow-derived glycoprotein that can stimulate monocytes and macrophages, resulting in production of factors involved in immune response. In vitro and in vivo preclinical studies in animals have demonstrated that recombinant human macrophage colony-stimulating factor (rHuM-CSF) can have antitumor activity. PURPOSE: A phase I clinical trial was undertaken to evaluate the toxicity, pharmacokinetics, and immunologic effects of rHuM-CSF given by continuous intravenous infusion in patients with cancer. METHODS: Eighteen patients with metastatic solid tumors refractory to conventional therapy were treated with rHuM-CSF. Twelve patients received two 14-day cycles of rHuM-CSF by continuous infusion, with a 2-week interval. Dose escalation levels were 50, 100, and 150 micrograms/kg over 24 hours. Consecutive cohorts of three to six patients were planned at each dose level. Six patients received a modified regimen of four 7-day periods of infusion at 100 micrograms/kg over 24 hours, with 1-week intervals. RESULTS: Dose-limiting toxicity was grade 4 thrombocytopenia at a dose of 150 micrograms/kg over 24 hours in two patients receiving the 2-week regimen. Platelet count nadirs and concomitant monocytosis were seen on days 7-9, but recovery occurred during the treatment period. Macrophage colony-stimulating factor serum levels were maximal on day 1 and returned to near baseline on day 7 of infusion. Patients treated with four 7-day infusions had no treatment-limiting thrombocytopenia. There were no cumulative effects on platelet or monocyte counts or significant constitutional symptoms. Subclinical conjunctival injection was noted in five of 10 patients receiving screening ophthalmologic evaluation. Grade 2 episcleritis was diagnosed in one patient, and asymptomatic perilimbal and retinal hemorrhages were seen in two. Two patients developed sepsis caused by the intravenous line, which required cessation of therapy. No objective responses were documented. CONCLUSION: The maximum tolerated dose of rHuM-CSF given by continuous intravenous infusion for 14 days was 100 micrograms/kg over 24 hours, with rapidly reversible, dose-limiting thrombocytopenia at 150 micrograms/kg over 24 hours. A regimen alternating weekly cycles of infusion avoids dose-limiting toxicity and allows long-term treatment. IMPLICATIONS: The regimen of repeated 7-day infusions may be useful for future studies evaluating rHuM-CSF-activated monocytes in therapy for long-term infectious diseases or in investigation of new modes of cancer therapy using rHuM-CSF in conjunction with a tumor-specific antibody.

The development of gene therapy for the treatment of cancer.

OBJECTIVE: The authors sought to develop new treatments for patients with cancer based on the genetic modification of immune lymphocytes and tumor cells designed to increase the host immune reaction against growing cancers. METHODS: Retroviral-mediated gene transduction was used to introduce genes into tumor-infiltrating lymphocytes (TIL), and these genetically altered TIL were administered to patients with cancer. Genes coding for cytokines were introduced into tumor cells, and these cells were used to immunize patients against their autologous cancers. RESULTS: In initial studies, the gene for neomycin phosphotransferase was introduced into the TIL of ten patients with advanced cancer to study the survival and distribution of TIL in humans. These studies showed that retroviral gene transduction is a safe and practical method for adding genes to human cells and led to clinical trials in which the gene for tumor necrosis factor (TNF) was inserted into TIL in an effort to increase their therapeutic effectiveness. Phase I trials are currently underway using TIL that secrete up to 100 times the normal level of TNF. More recently, animal experiments have revealed that transduction of tumor cells with cytokine genes can enhance tumor immunogenicity and, thus, increase the recognition of the tumor as foreign by the host. Clinical trials based on these observations have begun in which patients are immunized against their own autologous tumors that were transduced with the genes for TNF or interleukin-2. CONCLUSIONS: Attempts at gene therapy for cancer are underway and have opened new possibilities for the development of cancer treatments.

Collagenous colitis, eosinophilic colitis, and neutropenic colitis.

Neutropenic colitis is a complication of the treatment of hematologic malignancies and, less commonly, of other disease entities. The septic, inflammatory process has a predilection for the terminal ileum and right colon. While the pathogenesis is not clear, mucosal injury caused by several different mechanisms and local opportunistic infection play significant roles. An association has been recognized between neutropenic colitis and sepsis caused by C. septicum. Patients present with fever, diarrhea, and acute abdominal pain and tenderness often localized in the right lower quadrant. Sonography and CT are helpful in demonstrating colonic wall thickening and pericolic fluid. Peritoneal lavage has been used to exclude perforation in these critically ill patients. Although there has been debate about whether medical or operative management is best, the optimal initial therapy includes supportive care with gastric decompression, fluid and blood product replacement, and broad-spectrum antibiotics. The indications for surgery include continued intestinal bleeding despite correction of coagulopathy and pancytopenia, free intraperitoneal air, and uncontrolled sepsis. At operation, a right colectomy with ileostomy and mucous fistula or, in selected patients, primary anastomosis is the procedure of choice. Timely return of functioning neutrophils and the eventual prognosis of the primary disease are crucial to the overall success or failure of treatment of neutropenic colitis.

Phase I trial of subcutaneous interleukin-6 in patients with advanced malignancies.

PURPOSE: Based on preclinical evidence in murine models that interleukin-6 (IL-6) mediates regression of metastatic tumors, we performed a phase I study of recombinant human IL-6 in patients with refractory advanced malignancies to determine its pharmacokinetics, toxicities, and possible immunologic and antitumor effects. PATIENTS AND METHODS: Recombinant IL-6 was administered as a single subcutaneous dose daily for 7 days, with 7 days off therapy followed by another 7 days of IL-6. Doses were escalated in cohorts of three patients starting at 3 micrograms/kg/d, provided that toxicity at the preceding dose level was not dose-limiting. Dose-limiting toxicity was defined as grade III or IV major organ toxicity that did not resolve to grade II or less in 24 hours after stopping IL-6, using the National Cancer Institute Common Toxicity Criteria. Patients were treated with 3, 10, and 30 micrograms/kg/d IL-6 subcutaneously. RESULTS: Three patients each were treated at the 3- and 10-micrograms dose levels. Two of five patients treated with 30 micrograms/kg/d IL-6 subcutaneously had grade III major organ toxicity that required IL-6 therapy to be discontinued. All patients experienced fever, chills, and minor fatigue. Significant increases in C-reactive protein (CRP), fibrinogen, platelet counts, and lymphocyte IL-2 receptor levels were seen in patients at the 10- and 30-micrograms/kg dose levels. Decreases in albumin and hemoglobin were observed, particularly at the 30-micrograms/kg dose level. The half-life (T1/2 beta) was 4.2 hours, with a peak IL-6 level at 5 hours. No antitumor responses were seen. CONCLUSION: A safely tolerated dose of daily subcutaneous IL-6 is 10 micrograms/kg, with hepatotoxicity and cardiac arrhythmia being the dose-limiting toxicities at 30 micrograms/kg. Phase II trials of IL-6 administered subcutaneously daily for at least 7 days for two cycles with an intervening week of rest are recommended for phase II trials. However, patients with extensive replacement of liver by tumor and abnormal liver functions should receive IL-6 therapy with caution.

Prospective evaluation of unilateral adrenal masses in patients with operable non-small-cell lung cancer.

Although adrenal metastases are frequently noted with non-small-cell lung cancer (NSCLC) at autopsy, their incidence in patients with operable NSCLC is unclear. We prospectively assessed consecutive patients with otherwise operable NSCLC for the incidence and histology of unilateral adrenal masses. Assessment included blood chemistries, lung function tests, bronchoscopy, chest x-ray, bone scan, and computed tomography (CT) of the head, chest, and upper abdomen. Of 246 patients with otherwise operable NSCLC, 10 (4.1%) had a unilateral adrenal mass. Unilateral adrenal masses were needle-aspirated under CT control. If cytology was nondiagnostic, adrenalectomy was performed. Four (40%) of 10 patients had adrenal metastases proven by needle aspiration. Of the six (60%) patients with benign unilateral adrenal masses, one was demonstrated by needle aspiration. In the other five patients, a nondiagnostic needle aspiration led to adrenalectomy, which yielded two adenomas, two hyperplastic nodules, and one hemorrhagic cyst. There was no significant difference between the patients with benign and metastatic unilateral adrenal masses with respect to patient age or stage and size of adrenal mass. Patients with benign unilateral adrenal masses underwent curative resection of their NSCLC and had significantly prolonged survival compared with patients with metastatic unilateral adrenal masses treated with chemotherapy (P = .037). Median survival of patients with benign and metastatic unilateral adrenal masses was greater than 30 months and 9 months, respectively. In conclusion, the presence of unilateral adrenal masses in patients with otherwise operable NSCLC should not preclude thoracotomy without pathologic proof of metastatic disease.

Increased vascular permeability in organs mediated by the systemic administration of lymphokine-activated killer cells and recombinant interleukin-2 in mice.

Significant tumor regressions in mice with established carcinomas, sarcomas, and melanomas and in humans with advanced cancers have been observed following immunotherapy with lymphokine-activated killer (LAK) cells and recombinant interleukin-2 (IL-2). However, dose escalations of LAK cells and IL-2 have been prevented by the development of a vascular leak syndrome (VLS). Although IL-2 alone can produce this VLS, we investigated the role of transferred LAK cells, generated by the incubation of syngeneic splenocytes in IL-2, in mediating this phenomenon. We used a murine model to quantitate the vascular leak by measuring the extravasation of iv injected 125I-bovine serum albumin. A permeability index (PI) was calculated by dividing the mean cpm of tissues from treated mice by those from control animals. The systemic transfer of LAK cells and IL-2 produced a significantly greater extravasation of albumin in the lungs, liver, and kidneys than after Hanks' balanced salt solution, IL-2, or LAK cells alone (in the lungs, for example, PI = 4.7, 1.4, and 1.6 after LAK cells and IL-2, LAK cells alone, and IL-2 alone, respectively). To eliminate the contribution to the leak by host lymphocytes, we irradiated mice before cell transfer. As compared to controls, LAK cells and IL-2 resulted in higher extravasation in the lungs, liver, kidneys, and spleen. However, a similar vascular leak was not observed in the lungs, liver, and kidneys after treatment with IL-2 plus fresh or cultured (without IL-2) splenocytes. Moreover, the combination of IL-2 excipient and LAK cells or IL-2 and irradiated LAK cells did not produce a fluid leak. The development of the VLS by LAK cells was directly related to the dose of concurrently administered IL-2 and the number of injected cells. Depletion of Thy 1.2-positive lymphocytes using antibody and complement prior to generating the LAK cells used in adoptive transfer did not abrogate the VLS in any of the organs tested. Similarly, depletion of L3T4 and Lyt-2 positive cells in vivo using monoclonal antibodies prior to harvesting spleens for generation of LAK cells also had no impact on the VLS. In contrast, in vitro treatment of LAK precursor cells with antibody to asialo-GM-1 plus complement completely eliminated the VLS when the depleted cells were cultured in IL-2 and subsequently transferred.(ABSTRACT TRUNCATED AT 400 WORDS)

Hematologic effects of immunotherapy with lymphokine-activated killer cells and recombinant interleukin-2 in cancer patients.

Immunotherapy with interleukin-2 (IL-2) and lymphokine-activated killer (LAK) cells generated from autologous lymphocytes has produced significant tumor regressions in patients with advanced cancer. In the current study, we reviewed the hematologic effects associated with this therapy in our initial 42 patients. Eighty-eight percent of the treated patients developed anemia that required greater than or equal to 4 units of red cell transfusions, and 43% received at least 8 units. Only a blood loss of 2 to 3 units could be attributed to repeated phlebotomy, cytophereses, and hemodilution. IL-2 administration also resulted in thrombocytopenia as well as lymphopenia and eosinophilia. Forty-three percent of patients developed platelet counts of less than or equal to 50,000/microL, and 36% of the total group required platelet transfusions. Mild neutropenia and a rebound lymphocytosis followed discontinuation of IL-2 treatment. To explore the possible mechanisms for these hematologic effects, standard hematopoietic colony assays were conducted on serial blood samples from five patients. IL-2 produced a significant decline in circulating erythroid (BFU-E) and granulocytic/macrophage (CFU-C) progenitors, which rebounded after the discontinuation of IL-2 therapy. Infusion of IL-2 also resulted in measurable serum levels of gamma-interferon. Some of the hematologic effects of immunotherapy with LAK cells and IL-2 may be the result of IL-2-mediated suppression of hematopoiesis.

Clinical effects and toxicity of interleukin-2 in patients with cancer.

Interleukin-2 (IL-2) is a 15,000 dalton glycoprotein produced naturally by human T-cells during an immune response. IL-2 has been demonstrated to have substantial activity alone or in combination with the adoptive transfer of lymphokine-activated killer cells in murine tumor models. IL-2 derived from both natural (Jurkat human T-cell tumor) and recombinant (Escherichia coli) sources has been studied in Phase I protocols designed to evaluate toxicity in patients with a variety of solid tumors and to ascertain improvement in clinical parameters and immunologic status. A total of 16 patients (7 with acquired immune deficiency syndrome [AIDS] and 9 with non-AIDS malignancies) were treated with Jurkat derived IL-2. The total maximum dose (1.3 X 10(5) U/kg) was limited only by supply of this reagent. A total of 25 patients have been treated with recombinant IL-2 (RIL-2) alone. Dose-limiting toxicity manifested by marked malaise and weight gain was achieved with doses of RIL-2 of 10(6) U/kg as a single bolus or 3000 U/kg/hr. IL-2 could be administered intraperitoneally with similar toxicity. Minimal renal or hepatic toxicity was demonstrated. Hematologic toxicity was limited to mild anemia (25/25), thrombocytopenia (10/25), and marked reversible eosinophilia (15/25). Pronounced weight gain greater than 2 kg (16/25) occurred in most patients, primarily those who received cumulative doses of greater than 1-3 X 10(5) U/kg of IL-2. The weight gain amounted to as much as 10% to 20% of the pretreatment weight over 3 weeks of treatment and limited our ability to give higher doses. Two partial responses (greater than 50% decrease in cross sectional diameters) were seen in two patients with melanoma metastatic to the lung.

Prospective study of cardiomyopathy induced by adjuvant doxorubicin therapy in patients with soft-tissue sarcomas.

Since a combination of surgery and adjuvant high-dose doxorubicin therapy can prolong survival in patients with extremity sarcomas, but at the expense of significant cardiomyopathic changes, we prospectively studied the differences in cardiotoxicity in 118 patients with sarcomas treated with high- vs low-dose doxorubicin therapy following surgery. Cardiac function, as assessed by left ventricular ejection fraction (EF), was determined by standard radionuclide angiography during rest and exercise. No patients in this study developed congestive heart failure. While both regimens produced net decreases in EF during rest and exercise, the high-dose doxorubicin regimen resulted in significantly greater declines in EF than the low-dose protocol. Of patients with normal baseline values, a greater percentage of patients receiving the high-dose regimen developed an abnormal EF than did those receiving the low-dose regimen, even after separating younger from older individuals. Thus, treatment-induced cardiomyopathy appears to be a significant clinical problem after both high- and low-dose doxorubicin therapy. The use of the low-dose regimen decreases the magnitude of the cardiomyopathic changes.

Effect of corticosteroid on the antitumor activity of lymphokine-activated killer cells and interleukin 2 in mice.

The adoptive transfer of lymphokine-activated killer (LAK) cells combined with low dose interleukin 2 (IL-2) mediates the regression of established pulmonary metastases in mice and has efficacy in the treatment of human cancer. Systemic administration of high dose IL-2 alone can mediate tumor regression. Cortisone acetate (CA), 25-75 mg/kg, was administered daily to mice receiving high dose IL-2 for 10 days. CA significantly reduced the toxicity induced by IL-2; 38 of 48 mice receiving CA survived compared to 0 of 30 controls (P less than 0.0001). In addition, CA administration caused a decrease in IL-2-induced 125I-labeled albumin leakage in mouse organs. However, CA abrogated the in vivo antitumor effect of high dose IL-2, and to a lesser extent the therapeutic effect of exogenous LAK cells plus lower dose IL-2. Mice treated with 100,000 units of IL-2 showed 98, 63, and 33% reductions of pulmonary metastases in Hanks' balanced salt solution, 25 mg Ca/kg, and 75 mg Ca/kg groups, respectively; treatment with LAK and 7,500 units of IL-2 resulted in reductions of 94, 77, and 57% in these same groups. CA treatment of animals did not affect LAK generation, although the absolute number of LAK precursors was greatly reduced. These results show that although CA can reduce the toxic effect(s) of IL-2, it can be detrimental to successful immunotherapy using this approach.

Extravasation of intravascular fluid mediated by the systemic administration of recombinant interleukin 2.

Adoptive immunotherapy with lymphokine-activated killer cells and recombinant interleukin 2 (IL 2) can produce significant reduction of visceral metastases in tumor-bearing mice and, as shown recently, in humans with disseminated cancer. Because further dose escalations of IL 2 have been prevented by the development of a vascular leak syndrome (VLS) in both mice and humans, we investigated this VLS in mice undergoing the systemic administration of high-dose IL 2. A model for quantitating capillary permeability was used in which 125I-bovine serum albumin was injected i.v., and 2 hr later, tissues were counted in a gamma analyzer. A permeability index (PI) was calculated by dividing the mean counts per minute (cpm) of tissues from IL 2-treated mice by those from control animals. The injection of IL 2 produced increases in vascular permeability that were most pronounced in the thymus, spleen, lungs, liver, and kidneys (PI = 18.0, 10.0, 9.7, 6.7, and 6.3, respectively, on day 6). The development of the VLS was highly dependent on the number of days of IL 2 treatment (for example, the lungs contained 638, 1382, 3350, and 6187 cpm after 0, 1, 3, and 6 days of IL 2, respectively). Moreover, the degree of the VLS was directly related to the dose of IL 2 administered. Measurement of the wet and dry weights of lungs from IL 2-treated mice demonstrated that IL 2 produced a dramatic increase in their water weight (from 0.10 g at base line to 0.22 g after 200,000 U of IL 2 for 6 days). The injection of the IL 2 excipient failed to induce capillary leakage in tissues. Immunosuppression of mice by pretreatment irradiation (500 rad) or by injection of cyclophosphamide or by concurrent use of cortisone acetate markedly reduced or eliminated the development of the VLS. Similarly, the VLS was not observed in nude mice receiving IL 2. Thus, the administration of IL 2 produces a dose-limiting VLS that may be mediated, directly or indirectly, by host lymphoid elements.

Immunotherapy of murine sarcomas using lymphokine activated killer cells: optimization of the schedule and route of administration of recombinant interleukin-2.

Interleukin-2 (IL-2) at high doses or at low doses in concert with lymphokine-activated killer (LAK) cells can produce regression of established pulmonary and hepatic metastases from a variety of tumors in mice. IL-2 appears to mediate its antitumor effect through the generation of LAK cells in vivo from endogenous lymphocytes and by the stimulation of host and transferred LAK cell proliferation in tissues. In this paper we have investigated different strategies for IL-2 administration to determine which regimen produced maximal in vivo proliferation and optimal immunotherapeutic efficacy of LAK cells. Tissue expansion of lymphoid cells was assessed using an assay of in vivo labeling of dividing cells by the thymidine analogue, 5-[125I]iododeoxyuridine. The therapeutic effect of the different IL-2 administration protocols was determined by evaluating their efficacy in the treatment of established, 3-day pulmonary metastases from sarcomas in mice. The selection of IL-2 injection regimens for evaluation was based upon pharmacokinetic studies of IL-2 in mice. A single i.v. or i.p. dose yielded high peak IL-2 levels that could be measured for only a few hours after injection, while IL-2 given i.p. thrice daily produced titers that were detectable throughout the study periods (greater than or equal to 6 units/ml of serum after 100,000 units of IL-2 i.p. thrice daily). Using the proliferation and therapy models, we tested the same cumulative daily doses of IL-2 administered by i.v. or i.p. once daily, or i.p. thrice daily regimens. The i.p. thrice daily protocol stimulated greater lymphoid cell proliferation in the lungs, for example, than did the other regimens. Similarly, 300,000 units of IL-2 divided i.p. thrice daily were more successful in reducing metastases (n = 16) than was the entire dose given i.v. once daily (n = 190; P less than 0.05) or i.p. once daily (n = 71; P less than 0.05). When compared to the i.p. or i.v. once daily protocols, the i.p. thrice daily regimen for IL-2 also produced greater proliferation of exogenous LAK cells, as well as a more effective therapeutic outcome when IL-2 was combined with transferred LAK cells. Thus, sustained, lower levels of IL-2 were more effective than brief, high peak titers for stimulation of proliferation and antitumor activity. We then evaluated the effect of duration of IL-2 treatment as well as the number of LAK cell injections in the two models.(ABSTRACT TRUNCATED AT 400 WORDS)

Antitumor efficacy of lymphokine-activated killer cells and recombinant interleukin-2 in vivo: survival benefit and mechanisms of tumor escape in mice undergoing immunotherapy.

The studies described in this paper showed that the combination of i.v.-transferred lymphokine-activated killer (LAK) cells and i.p. injections of recombinant interleukin-2 (RIL-2) was highly effective in vivo in reducing established pulmonary metastases of natural killer cell-resistant, MCA-105 sarcoma and B16 melanoma in mice. A 3-day in vitro incubation of normal C57BL/6 splenocytes in medium containing pure RIL-2 generated LAK cells that, when combined with RIL-2, reduced the mean number of established pulmonary micrometastases of the B16 melanoma and of the MCA-105 sarcoma from 179 and 140, respectively (in groups treated with Hanks' balanced salt solution alone), to 12 (P = 0.01) and 6 (P = 0.01), respectively. This combined immunotherapy also consistently resulted in significant prolongation of survival in mice with established, 3-day or 10-day pulmonary metastases of the MCA-105 sarcoma. Mice autopsied at time of death revealed a massive involvement of tumor in the lungs and liver in the group receiving Hanks' balanced salt solution alone compared to a small number of residual large lung or liver metastases in the group receiving LAK cells plus RIL-2. Experiments were designed to test whether variants existed in the original tumor cell inoculum that were resistant to killing by LAK cells and thus could account for the metastases that "escaped" the combined immunotherapy of LAK cells plus RIL-2 in vivo. Metastases of the MCA-105 sarcoma that escaped the combined therapy of LAK cells plus RIL-2 were dissected from the organs of mice upon autopsy and directly tested for susceptibility in vitro to lysis by LAK cells in 4-h and 18-h 51Cr release assays. Target cells derived from the metastases were lysed to an equivalent extent as those prepared from a fresh MCA-105 sarcoma that was growing s.c. In addition, successful reduction of pulmonary metastases established by the i.v. infusion of MCA-105 sarcoma cells obtained from metastases that escaped a prior round of therapy with LAK cells and RIL-2 could be achieved in vivo by the combined immunotherapy as well as by high doses of RIL-2 alone. Culture adapted, natural killer cell-resistant B16 melanoma cells surviving two successive treatments with LAK cells in vitro remained as susceptible to LAK cell lysis as untreated B16 melanoma cells in 18-h 51Cr release assays.(ABSTRACT TRUNCATED AT 400 WORDS)