Intratumoral injection of IL-12 plasmid DNA--results of a phase I/IB clinical trial.

Effective eradication of established tumor and generation of a lasting systemic immune response are the goals of cancer immunotherapy. The objective of this phase IB study was to assess the safety and toxicity of treatment to metastatic tumor underlying the skin with the DNA encoding interleukin-12 (IL-12). This treatment strategy allowed the patient's own tumor to serve as a source of autologous antigen in the tumor microenvironment. We proposed that IL-12 protein produced by the transfected cells would result in the generation of both a local and systemic antitumor response. The tumor was treated with either three or six intratumoral injections of plasmid containing IL-12 DNA. This treatment strategy resulted in no significant local or systemic toxicity. The treatment did not result in an increase in serum IL-12 protein. The size of the treated lesion decreased significantly (greater than 30%) in five of the 12 patients. However, nontreated subcutaneous lesions or other disease did not decrease in size.

Donor-derived small cell lung carcinoma in a kidney transplant recipient.

BACKGROUND: Transplantation of donor-derived malignancies during organ transplantation fortunately is very rare. Discontinuation of immunosuppressive medications under these circumstances has previously resulted in complete tumor rejection. Ectopic adrenocorticotropic hormone (ACTH) production may result in Cushing syndrome and is not an uncommon paraneoplastic feature of small cell carcinoma of the lung. Theoretically, in the organ transplantation setting, the resulting high cortisol levels could suppress a tumor-rejection immune response. However, to the authors' knowledge, no such clinical scenario has been described in the literature published to date. METHODS: A 25-year-old living related kidney transplant recipient presented with Cushing syndrome 32 months after transplantation. The donor had been diagnosed with small cell carcinoma of the lung 22 months earlier. On further evaluation, the kidney recipient was diagnosed with donor-derived small cell lung carcinoma of the transplanted kidney. She was found to have extensive disease involving the liver and retroperitoneum. Despite discontinuation of immunosuppressive medications, the disease progressed and cortisol levels remained elevated during 6 weeks of observation. RESULTS: The patient received six cycles of cisplatin and etoposide, which resulted in resolution of her hypercortisolemia and a complete remission of her donor-derived small cell carcinoma. At last follow-up, she was 12 months from completing her therapy and continued in complete remission. CONCLUSIONS: Donor-derived small cell carcinoma and ectopic ACTH production can occur in a patient after kidney transplantation.

In vivo mutant frequency of thioguanine-resistant T-cells in the peripheral blood and lymph nodes of melanoma patients.

T-cell activation by malignant melanoma would be anticipated to stimulate T-cell proliferation, which in turn has been associated with increasing the likelihood of somatic gene mutation. The purpose of this study was to test the hypothesis that in vivo hypoxanthine guanine phosphoribosyltransferase (hprt) mutant frequencies (MFs) are increased in peripheral blood T-cells from melanoma patients compared to normal controls. Assays were made of 48 peripheral blood samples from melanoma patients with stage 3 (13 patients) and stage 4 (35 patients) disease, 38 normal controls, and of nine tumor bearing lymph nodes. The mean hprt log(10)(MF) in patient peripheral blood was -4.77 (geometric mean hprt MF=17.0x10(-6)) compared to a mean hprt log(10)(MF) of -4.87 (geometric mean hprt MF=13.5x10(-6)) in controls. Although modest, this difference is statistically significant both by t-test (P=0.049) and after adjustment for covariates of age, gender, and cigarette smoking by regression analysis (P=0.001). Among the melanoma patients, the mean log(10)(MF) for the 17 patients who had received potentially genotoxic therapies was not significantly different from the mean log(10)(MF) for the 31 patients not receiving such therapies. The hprt MFs in the nine tumor bearing nodes were compared with MFs in peripheral blood from the same patients and revealed a non-significant (P=0.07) trend for increasing MFs in blood. Furthermore, analyses of T-cell receptor gene rearrangement patterns revealed hprt mutants originating from the same in vivo clone in both peripheral blood and a tumor-bearing node. The finding of elevated hprt MFs not entirely explained by genotoxic therapies in patients compared to controls can be explained either by hypermutability or in vivo T-cell activation. The similar MFs in peripheral blood and tumor bearing lymph nodes, as well as the finding of mutant representatives of the same in vivo T-cell clone in both locations, support monitoring peripheral blood to detect events in the nodes. If in vivo proliferation accounts for the current findings, the hprt deficient (hprt-) mutant fraction in blood may be enriched for T-cells that mediate the host immune response against malignant melanoma. Further studies will characterize the functional reactivity of hprt mutant isolates against melanoma-related antigens.

Effective particle-mediated vaccination against mouse melanoma by coadministration of plasmid DNA encoding Gp100 and granulocyte-macrophage colony-stimulating factor.

Particle-mediated gene delivery was used to immunize mice against melanoma. Mice were immunized with a plasmid cDNA coding for the human melanoma-associated antigen, gp100. Murine B16 melanoma, stably transfected with human gp100 expression plasmid, was used as a tumor model. Particle-mediated delivery of gp100 plasmid into the skin of naïve mice resulted in significant protection from a subsequent tumor challenge. Co-delivery of murine granulocyte-macrophage colony-stimulating factor (GM-CSF) expression plasmid together with the gp100 plasmid consistently resulted in a greater level of protection from tumor challenge. The inclusion of the GM-CSF plasmid with the gp100 DNA vaccine allowed a reduction in the gp100 plasmid dose required for antitumor efficacy. Protection from tumor challenge was achieved with as little as 62.5 ng of gp100 DNA per vaccination. Tumor protection induced by the gp100 + GM-CSF gene combination was T cell mediated, because it was abrogated in vaccinated mice treated with anti-CD4 and anti-CD8 monoclonal antibodies. In addition, administration of the gp100 + GM-CSF DNA vaccine to mice bearing established 7-day tumors resulted in significant suppression of tumor growth. These results indicate that inclusion of GM-CSF DNA augments the efficacy of particle-mediated vaccination with gp100 DNA, and this form of combined gp100 + GM-CSF DNA vaccine warrants clinical evaluation in melanoma patients.

B7.1 expression eliminates tumor resistance to IL-12 gene therapy.

IL-12 gene therapy results in tumor regression in some, but not all, murine models. We hypothesized that expression of B7.1 on the tumor cell surface was necessary for IL-12-mediated tumor regression. In addition, we hypothesized that all cells must express B7.1 for this to be effective. To evaluate this hypothesis, tumor nodules were established in mice with either wild-type B16 melanoma or with B16 melanoma modified to express B7.1. IL-12 cDNA was transferred to the tumor by particle-mediated gene transfer. All tumors modified to express B7.1 regressed completely after IL-12 cDNA treatment. When the percent of B7.1-transfected B16 cells was decreased to 50%, no animals survived after treatment. Animals rendered tumor-free were then challenged with wild-type B16. Fifty percent of mice was protected from this tumor challenge. Expression of CD28 (the stimulatory B7.1 ligand) was significantly increased in both CD8(+) T cells and natural killer cell populations of mice rejecting tumor challenge compared to mice with tumor growth. These results suggest that the costimulatory molecule B7.1 is required for initial tumor sensitivity to IL-12 gene therapy and that protection from subsequent challenge with B7.1 (-) tumor is mediated by CD28(+) immune effector cells.

Central venous device-related infection and thrombosis in patients treated with moderate dose continuous-infusion interleukin-2.

BACKGROUND: This study was performed to determine the incidence of central venous device-related blood stream infection and thrombosis in patients treated with moderate dose continuous-infusion interleukin-2 (IL-2). METHODS: The records of 160 consecutive patients treated at the University of Wisconsin Hospital and Clinics, between June 1990 and June 1997, with moderate dose continuous-infusion IL-2 (IL-2 [1.5-3.0 x 10(6) U/m(2)/day] Hoffman-LaRoche, Nutley, NJ or IL-2 [4.5 x 10(6) U/m(2)/day] Chiron Corporation, Berkley, CA) were reviewed retrospectively. The majority of patients had metastatic melanoma (78 patients) or renal cell carcinoma (70 patients). All of the patients had a surgically implanted central venous device placed before starting IL-2 therapy; 89% of these were cuffed Hickman catheters. Eighty-four patients received 1 mg of warfarin per day as prophylaxis against device-related thrombosis; none received periinsertion prophylactic antibiotics. RESULTS: Twenty-one patients (13%) developed central venous device-related bloodstream infection (DRBSI) during the study period, a rate of 2 DRBSI per 1000 device-days. DRBSIs were associated with the type of immunotherapy given with IL-2 (P = 0.01) and with thrombosis (odds ratio, 4.1; 95% confidence interval, 1.5-11.4; P = 0.008) but not with patient gender, type of cancer, duration of the central device, or site of device placement. Twenty-six patients (16%) developed central venous device-related thrombosis (DRT) during immunotherapy. Low dose warfarin did not appear to prevent thrombosis. Device-related thrombosis was associated with DRBSI but not with patient gender, type of cancer, type of device, duration or location of device, or concomitant immunotherapy. CONCLUSIONS: Central venous DRBSI and DRT are significant complications that can occur during moderate dose continuous-infusion IL-2 therapy. The risk of DRBSI appears lower than the risk reported with high dose IL-2 therapy by previous investigators. The risk of DRT appears to be higher than the risk reported for patients with similar devices but not given IL-2. Low dose warfarin did not prevent DRT when started after device placement.

Antigenicity of human melanoma cells transfected to express the B7-1 co-stimulatory molecule (CD80) varies with the level of B7-1 expression.

The aim of this study was to compare the antigenicity of human melanoma cells molecularly modified by particle-mediated gene transfer to have transient or stable expression of the B7-1 co-stimulatory molecule (CD80). The unmodified melanoma cells (mel5, m21) had no constitutive expression of B7-1, but 22%-28% of cells had transient B7-1 expression 24 h following transfection with cDNA for B7-1 (mel5-B7, m21-B7). In addition, 85%-90% of cells had stable B7-1 expression following transfection with cDNA for B7-1 and in vitro culture under selection conditions (mel5-B7neo, m21-B7neo). Allogeneic HLA-unmatched normal donor peripheral blood mononuclear cells (PBMC) secreted greater amounts of granulocyte/macrophage-colony-stimulating factor (GM-CSF) when incubated for 3 days with m21-B7neo than did PBMC incubated with m21-B7, which, in turn, secreted greater amount of GM-CSF than PBMC incubated with m21. Similarly, cell-mediated cytotoxicity against unmodified melanoma cells by PBMC co-cultured for 5 days with the modified or unmodified melanoma cells was proportional to the level of B7-1 expression on the stimulating cells. This cytolytic activity had both an HLA-class-I-restricted and an HLA-class-I-unrestricted component. Following 5 days of co-culture, PBMC expression of CD28, the ligand for B7-1, was down-regulated in proportion to the level of B7-1 expression on the stimulating melanoma cells. Thus, particle-mediated gene delivery of cDNA for B7-1 into human melanoma cells increased expression of functional B7-1 and enhanced the antigenicity of the gene-modified cells in proportion to their level of B7-1 expression.

Dermatomyositis after interferon alpha treatment.

An association between auto-immune disorders and interferon (IFN) has been reported. High levels of natural IFNalpha are present in the blood of patients with auto-immune disease and correlate with disease activity. In addition, IFNalpha treatment of humans has resulted in multiple reports of associated auto-immune phenomena. We describe a patient who underwent resection of regionally metastatic melanoma, was given adjuvant high-dose IFNalpha2b, and subsequently developed dermatomyositis. To the authors' knowledge this is the first report of dermatomyositis in association with IFNalpha treatment. We review the literature reporting associations between IFNalpha and auto-immune disease and discuss possible mechanisms by which IFNalpha may contribute to the development of auto-immune disease. High dose IFNalpha2b is more commonly prescribed since it was approved as an adjuvant treatment for patients with surgically resected high-risk melanoma. The potential for cases of IFN-associated auto-immune disease is therefore a clinical concern. Standard side effects of high-dose IFN therapy resemble symptoms of auto-immune diseases, which may make prompt diagnosis difficult. Therefore, it is important that auto-immune diseases such as dermatomyositis are recognized as potential side effects of treatment with high-dose IFNalpha.

Preclinical development of human granulocyte-macrophage colony-stimulating factor-transfected melanoma cell vaccine using established canine cell lines and normal dogs.

Tumor vaccines and gene therapy have received significant attention as means of increasing cellular and humoral immune responses to cancer. We conducted a pilot study of seven research dogs to determine whether intradermal injection of canine tumor cells transfected via the Accell particle-mediated gene transfer device with the cDNA for human granulocyte-macrophage colony-stimulating factor (hGM-CSF) would generate biologically relevant levels of protein and result in demonstrable histological changes at sites of vaccination. Tumor cell vaccines of 10(7) irradiated canine melanoma cells were nontoxic, safe, and well tolerated. No significant alterations in blood chemistry values or hematological profiles were detected. A histological review of control vaccine sites revealed inflammatory responses predominated by eosinophils, whereas vaccine sites with hGM-CSF-transfected tumor cells had an influx of neutrophils and macrophages. Enzyme-linked immunosorbent assays of skin biopsies from vaccine sites had local hGM-CSF production (8.68-16.82 ng/site of injection) at 24 hours after injection and detectable levels (0.014-0.081 ng/site) for < or =2 weeks following vaccination. Flow cytometric analysis of hGM-CSF-transfected cells demonstrated < or =25% transfection efficiency, and hGM-CSF levels obtained during time-course assays demonstrated biologically relevant levels for both irradiated and nonirradiated samples. These data demonstrate the in vivo biological activity of irradiated hGM-CSF-transfected canine tumor cells and help provide evidence for a valid translational research model of spontaneous tumors.

Development of human granulocyte-macrophage colony-stimulating factor-transfected tumor cell vaccines for the treatment of spontaneous canine cancer.

Cytokine gene-engineered tumor vaccines are currently an area of intense investigation in both basic research and clinical medicine. Our efforts to utilize tumor vaccines in an immunotherapeutic manner involve canines with spontaneous tumors. We hypothesized that canine tumor cells, transfected with human granulocyte-macrophage colony-stimulating factor (hGM-CSF) cDNA in a plasmid vector, would prove nontoxic following intradermal administration, generate biologically relevant levels of protein, effect local histological changes at the sites of vaccination, and create a systemic antitumor response. Sixteen tumor-bearing dogs were admitted to a study of ex vivo gene therapy. Tumor tissue was surgically removed, enzymatically and mechanically dissociated, irradiated, transfected, and intradermally injected back into the patients. The dogs were vaccinated with primary autologous tumor cells transfected with hGM-CSF or a reporter control gene. hGM-CSF protein was detected (0.07 to 14.15 ng/vaccination site) at 24 hr postinjection and dramatic histological changes were observed, characterized by neutrophil and macrophage infiltration at the sites of injection of hGM-CSF-transfected tumor cells. This was in stark contrast to the lesser neutrophilic and eosinophilic infiltrates found at control vaccination sites. Objective evidence of an antitumor response was observed in three animals. These data, in a large animal translational model of spontaneous tumors, demonstrate in vivo biological activity of hGM-CSF-transfected autologous tumor cell vaccines.

Phase IB trial of chimeric antidisialoganglioside antibody plus interleukin 2 for melanoma patients.

We conducted a Phase IB trial of antidisialoganglioside chimeric 14. 18 (ch14.18) antibody and interleukin 2 (IL-2) to determine the maximal tolerated dose (MTD), immunological effects, antitumor effects, and toxicity of this treatment combination. Twenty-four melanoma patients received immunotherapy with ch14.18 antibody and a continuous infusion of Roche IL-2 (1.5 x 10(6) units/m2/day) given 4 days/week for 3 weeks. The ch14.18 antibody (dose level, 2-10 mg/m2/day) was scheduled to be given for 5 days, before, during, or following initial systemic IL-2 treatment. The ch14.18 MTD was 7.5 mg/m2/day, and 15 patients were treated with the ch14.18 MTD. Immunological effects included the induction of lymphokine-activated killer activity and antibody-dependent cellular cytotoxicity by peripheral blood mononuclear cells. In addition, serum samples obtained following ch14.18 infusions were able to facilitate in vitro antibody-dependent cellular cytotoxicity. Antitumor activity included one complete response, one partial response, eight patients with stable disease, and one patient with >50% decrease of hepatic metastases in the face of recurrence of a s.c. lesion. Dose-limiting toxicities were a severe allergic reaction and weakness, pericardial effusion, and decreased performance status. Most patients treated at the MTD had abdominal, chest, or extremity pain requiring i.v. morphine. One patient had an objective peripheral neuropathy. This IL-2 and ch14.18 treatment combination induces immune activation in all patients and antitumor activity in some melanoma patients. We are attempting to enhance this treatment approach by addition of the anti-GD3 R24 antibody to this IL-2 and ch14.18 regimen.

Phase I/IB study of immunization with autologous tumor cells transfected with the GM-CSF gene by particle-mediated transfer in patients with melanoma or sarcoma.

The objective of this Phase I study is to assess the acute and long-term toxicities of intradermal vaccination of cancer patients with lethally-irradiated tumor cells that have been transfected by particle-mediated gene transfer (PMGT) with gold particles coated with human granulocyte-macrophage colony stimulating factor (GM-CSF) DNA in a plasmid expression vector. The GM-CSF DNA-coated gold particles are delivered to tumor cells using helium pressure with a hand held gene delivery device. Preclinical studies have demonstrated that vaccination of mice with irradiated, GM-CSF-transfected melanoma cells provided protection from subsequent challenges with non-irradiated, non-transfected tumor cells. Ongoing human tumor immunotherapy studies use patients' melanoma or renal carcinoma cells transfected with a retroviral vector containing GM-CSF cDNA as a vaccine to elicit anti-tumor immune responses. PMGT transfection, unlike retroviral transfection, does not require tumor cells to proliferate in vitro to undergo gene transfer. Instead, tumor tissue can be dissociated into small tissue clumps or cell aggregates and then immediately transfected using the gene gun. PMGT physically inserts the DNA without the need for cell surface interaction with viral components or exposure of the patient to viral antigens. As described in this protocol, fresh human sarcoma and melanoma specimens can be transfected with the GM-CSF DNA-coated gold particles with subsequent production of biologically active GM-CSF protein. In this study tumor tissue will be obtained from patients with melanoma or sarcoma. Tumor tissue will be dissociated, irradiated, and transfected with GM-CSF DNA by PMGT. In this ascending dosage study, two dose levels of GM-CSF DNA will be studied in 2 groups of 6 patients each. Patients will receive two intradermal injections of the irradiated, transfected tumor in a single extremity. On days 3 and 14 post-vaccination, patients will undergo surgical excision of the vaccination sites to assess GM-CSF production and infiltration of immune effector cells. On Day 25, patients will undergo DTH testing with intradermal injection in their opposite extremity of 5 x 10(6) irradiated non-transfected autologous tumor cells cryopreserved at the time of vaccine preparation. This injection site will be assessed on day 28 post-vaccination and surgical excision of the DTH testing site will be performed on day 28 if a positive reaction is noted. The patients will be observed for local and systemic toxicity on days 2, 3, 5, 8, 14, 25, and 28 after the vaccination. Restaging of the patients' disease and long term toxicity evaluation will be performed at 3, 6, and 12 months and then yearly.

Tumor growth, weight loss and cytokines in SCID mice.

It has been proposed that immunoregulatory cytokines play a role in the onset and development of cancer cachexia, although evidence supporting this theory remains inconclusive. In the present study, SCID mice were implanted with one of two tumor cell lines known to induce weight loss in rats. Growth of the Morris 7777 hepatoma was associated with weight loss as well as increased levels of tumor necrosis factor and interleukins 1 and 6 in spleen cells of tumor-bearing mice. Growth of the MCA sarcoma did not induce weight loss, nor did it increase cytokine expression in spleen cells of tumor-bearing mice. We conclude that increased cytokine expression is associated with weight loss in tumor-bearing SCID mice, and immune activation for cytokine expression does not require the presence of T or B cells.

Systemic interleukin-2 modulates the anti-idiotypic response to chimeric anti-GD2 antibody in patients with melanoma.

The induction of human antimouse antibodies (HAMA) and human anti-idiotypic (anti-Id) responses in cancer patients receiving therapeutic monoclonal antibody (mAb) may limit the effectiveness of the administered mAb. This report evaluates the influence of systemic interleukin-2 (IL-2) on the anti-Id response to anti-disialoganglioside (anti-GD2) antibody given as treatment for patients with melanoma. Twenty-eight patients with melanoma received combined immunotherapy with anti-GD2 antibody and IL-2 at 1.5 x 10(6) U/m2/day given 4 days/week. The anti-GD2 antibody [murine 14.G2a mAb; dose levels of 2-5 mg/m2/day (4 patients); or human-mouse chimeric 14.18 (ch14.18) antibody; dose levels of 2-10 mg/m2/day (24 patients)] was scheduled to be given for 5 days either before, during, or after initial systemic IL-2 treatment. All four patients who received murine 14.G2a developed HAMA anti-isotype antibodies (660-1,000 ng/ml) as well as measurable anti-Id antibodies. All three patients who received initial treatment with ch14.18 alone developed a strong anti-Id antibody response after IL-2 was started 1 week later. The serum level of anti-Id antibody decreased during subsequent ch14.18 infusions, suggesting that the anti-Id antibody may be binding the administered ch14.18. In contrast, measurable anti-Id antibody was detected in only 3 of 14 patients who received IL-2 before, during, and after initial ch14.18 administration. Two of four patients receiving systemic IL-2 before and during initial ch14.18 infusions, and two of three patients receiving systemic IL-2 concurrent with initial ch14.18 infusions developed anti-Id antibodies. These data suggest that the anti-Id response to chimeric anti-GD2 antibody is influenced by the timing of systemic IL-2 in relation to antibody administration and can be suppressed by systemic treatment with IL-2 given before, during, and after the antibody administration.

Anti-renal-cell carcinoma chimeric antibody G250 facilitates antibody-dependent cellular cytotoxicity with in vitro and in vivo interleukin-2-activated effectors.

Renal cell carcinoma (RCC) is relatively resistant to chemotherapy and radiotherapy, whereas treatment with biologics has achieved limited success. Although monoclonal antibodies able to recognize human RCC have been identified, most induce little complement-dependent cytotoxicity or antibody-dependent cellular cytotoxicity (ADCC), and thus are of limited potential as therapeutic modalities in their natural conformation. We evaluated a human/ mouse chimeric derivative of the previously described G250 murine monoclonal antibody (mAb), reactive with RCC, to identify a reagent for potential immunotherapy. This chimeric antibody (ch-G250) is composed of the murine variable region from the G250 mAb, which recognizes a tumor-associated antigen expressed on 95% of primary and 86% of metastatic renal cell carcinomas. The constant region of the ch-G250 is comprised of the human IgG1 isotype domains. This chimeric antibody does not bind to normal renal tissue or other normal human tissues, with the exception of gastric mucosal cells and large bile-duct epithelium. Clinical radiolocalization studies have demonstrated the relative tumor-targeting potential of this radiolabeled antibody. This ch-G250 antibody facilitated potent ADCC against several RCC lines when using in vitro and in vivo interleukin-2 (IL-2)-activated peripheral blood mononuclear cells obtained from healthy control donors and patients with cancer, respectively. This lymphocyte-mediated ADCC was specific for RCC cells recognized by the ch-G250 antibody. Using flow cytometry, we found that the level of ADCC was directly related to the degree of binding of ch-G250 to the renal cell target. These in vitro data suggest that this antibody may improve efficacy of IL-2 therapy by targeting cytokine-activated effector cells directly to the tumor and facilitating in vivo ADCC. Clinical studies combining this chimeric antibody with IL-2 treatment will be needed to test the antitumor effects of this ADCC effect in vivo.

Dual expression of human leukocyte antigen molecules and the B7-1 costimulatory molecule (CD80) on human melanoma cells after particle-mediated gene transfer.

The aim of this study was to determine if human melanoma cells could be molecularly modified by particle-mediated gene transfer with a "gene gun", using genes for interferon-gamma (IFN-gamma), the B7-1 costimulatory molecule (CD80), and human leukocyte antigen (HLA)-A2, to augment expression of both HLA molecules and B7-1. Established and early passage melanoma cells transfected with human IFN-gamma complementary DNA (cDNA) produced IFN-gamma (50-5,000 pg/mL). The biological effect of this IFN-gamma transgene included an upregulation, or de novo appearance, of HLA expression. These melanoma cells had no detectable baseline surface expression of the B7-1 costimulatory molecule, but 8% to 31% of these cells became B7-1 positive with no selection procedure after gene transfer with human B7-1 cDNA. After combination gene transfer with cDNAs for both IFN-gamma and B7-1, 9% to 33% of these cells expressed both HLA-DR and B7-1. In combination gene transfer experiments with cDNAs for both HLA-A2 and B7-1, dual expression of HLA-A2 and B7-1 was achieved in 10% to 17% of the melanoma cells. Thus, the molecular modification of human melanoma cells to increase expression of both HLA and B7-1 can be achieved by particle-mediated gene delivery and presents a promising strategy to stimulate antimelanoma T-cell immunity. Key words: Melanoma; T cells; B7-1 costimulatory molecule (CD80); major histocompatibility complex.

Clinical and immunological effects of granulocyte-macrophage colony-stimulating factor coadministered with interleukin 2: a phase IB study.

Interleukin 2 (IL-2) and granulocytes-macrophage colony-stimulating factor (GM-CSF) are activators of the lymphocyte and granulocyte/macrophage series, respectively. We conducted a phase IB trial to identify the maximally tolerated dose and to assess immunological effects of the combination. Thirty-four patients with incurable cancers received 2.5, 5, or 10 microgram/kg GM-CSF s.c. either before or concurrently with 1.5 or 3.0 million units/m2/day IL-2. The most common laboratory and clinical side effects included an elevation of the total WBC or eosinophil count due to GM-CSF, and constitutional symptoms due to IL-2. Grade 3 or 4 toxicities included hypotension, thrombocytopenia, elevations in aspartate aminotransferase or bilirubin, renal toxicity, gastrointestinal hemorrhage, arrhythmia, and constitutional symptoms. Two patients receiving 5.0 microgram/kg GM-CSF plus concurrent 3.0 million units IL-2 experienced dose-limiting grade 3 or 4 neurological toxicity, which reversed almost completely. An increase in the serum-soluble IL-2 alpha chain receptor was observed with administration of GM-CSF, IL-2, or the combination. IL-2 therapy enhanced lymphokine-activated killer activity, antibody-dependent cellular cytotoxicity, and lymphocyte activation, with increased CD16 and CD56 expression. GM-CSF increased expression of human leukocyte antigen DR on peripheral blood monocytes and decreased surface expression of CD16 on circulating monocytes and polymorphonuclear cells. Lymphokine-activated killer activity and CD16 expression on monocytes and lymphocytes and CD56 expression on lymphocytes were significantly lower in patients receiving GM-CSF simultaneously with IL-2 than in patients receiving the sequential treatment. Antitumor activity was observed in the lungs of four of eight renal cell carcinoma patients with pulmonary metastases treated with concurrent GM-CSF and IL-2. Although no or minimal shrinkage was observed in the patients' large primary tumors, these results warrant further study. The recommended initial Phase II dose and schedule is 1.25 microgram/kg/day GM-CSF, given concurrently with 1.5 million Roche units/m2/day (4.5 x 10(6) international units/m2/day) IL-2, with subsequent escalation of GM-CSF to 2.5 microgram/kg/day after careful observation for toxicities.