Pathologic features of response to neoadjuvant anti-PD-1 in resected non-small-cell lung carcinoma: a proposal for quantitative immune-related pathologic response criteria (irPRC).

Background: Neoadjuvant anti-PD-1 may improve outcomes for patients with resectable NSCLC and provides a critical window for examining pathologic features associated with response. Resections showing major pathologic response to neoadjuvant therapy, defined as ≤10% residual viable tumor (RVT), may predict improved long-term patient outcome. However, %RVT calculations were developed in the context of chemotherapy (%cRVT). An immune-related %RVT (%irRVT) has yet to be developed. Patients and methods: The first trial of neoadjuvant anti-PD-1 (nivolumab, NCT02259621) was just reported. We analyzed hematoxylin and eosin-stained slides from the post-treatment resection specimens of the 20 patients with non-small-cell lung carcinoma who underwent definitive surgery. Pretreatment tumor biopsies and preresection radiographic 'tumor' measurements were also assessed. Results: We found that the regression bed (the area of immune-mediated tumor clearance) accounts for the previously noted discrepancy between CT imaging and pathologic assessment of residual tumor. The regression bed is characterized by (i) immune activation-dense tumor infiltrating lymphocytes with macrophages and tertiary lymphoid structures; (ii) massive tumor cell death-cholesterol clefts; and (iii) tissue repair-neovascularization and proliferative fibrosis (each feature enriched in major pathologic responders versus nonresponders, P < 0.05). This distinct constellation of histologic findings was not identified in any pretreatment specimens. Histopathologic features of the regression bed were used to develop 'Immune-Related Pathologic Response Criteria' (irPRC), and these criteria were shown to be reproducible amongst pathologists. Specifically, %irRVT had improved interobserver consistency compared with %cRVT [median per-case %RVT variability 5% (0%-29%) versus 10% (0%-58%), P = 0.007] and a twofold decrease in median standard deviation across pathologists within a sample (4.6 versus 2.2, P = 0.002). Conclusions: irPRC may be used to standardize pathologic assessment of immunotherapeutic efficacy. Long-term follow-up is needed to determine irPRC reliability as a surrogate for recurrence-free and overall survival.

Immunologic and therapeutic evaluation of a synthetic peptide vaccine for the treatment of patients with metastatic melanoma.

The cloning of the genes encoding cancer antigens has opened new possibilities for the treatment of patients with cancer. In this study, immunodominant peptides from the gp100 melanoma-associated antigen were identified, and a synthetic peptide, designed to increase binding to HLA-A2 molecules, was used as a cancer vaccine to treat patients with metastatic melanoma. On the basis of immunologic assays, 91% of patients could be successfully immunized with this synthetic peptide, and 13 of 31 patients (42%) receiving the peptide vaccine plus IL-2 had objective cancer responses, and four additional patients had mixed or minor responses. Synthetic peptide vaccines based on the genes encoding cancer antigens hold promise for the development of novel cancer immunotherapies.

Melanoma-specific CD4+ T cells recognize nonmutated HLA-DR-restricted tyrosinase epitopes.

Tyrosinase was the first melanoma-associated antigen shown to be recognized by CD4+ T cells. In this study, we have identified two HLA-DRB1*0401-restricted peptides recognized by these T cells: Ty 56-70 and Ty 448-462. As with many of the MHC class I-restricted melanoma epitopes, both are nonmutated self peptides that have intermediate and weak MHC binding affinities, respectively. Mutated and truncated versions of these peptides were used to define their MHC binding anchor residues. Anchor residues were then modified to derive peptides with increased MHC binding affinities and T cell stimulatory properties. Ty 56-70 and Ty 448-462 enhance the list of immunogenic HLA-A2-, A24-, and B44-restricted tyrosinase peptides already described. Thus, tyrosinase provides a model for anti-melanoma vaccines in which a single molecule can generate multivalent immunization incorporating both CD4+ and CD8+ T cell responses.

Biochemical identification of a mutated human melanoma antigen recognized by CD4(+) T cells.

CD4(+) T cells play a critical role in generating and maintaining immune responses against pathogens and alloantigens, and evidence suggests an important role for them in antitumor immunity as well. Although major histocompatibility complex class II-restricted human CD4(+) T cells with specific antitumor reactivities have been described, no standard method exists for cloning the recognized tumor-associated antigen (Ag). In this study, biochemical protein purification methods were used in conjunction with novel mass spectrometry sequencing techniques and molecular cloning to isolate a unique melanoma Ag recognized by a CD4(+) tumor-infiltrating lymphocyte (TIL) line. The HLA-DRbeta1*0101-restricted Ag was determined to be a mutated glycolytic enzyme, triosephosphate isomerase (TPI). A C to T mutation identified by cDNA sequencing caused a Thr to Ile conversion in TPI, which could be detected in a tryptic digest of tumor-derived TPI by mass spectrometry. The Thr to Ile conversion created a neoepitope whose T cell stimulatory activity was enhanced at least 5 logs compared with the wild-type peptide. Analysis of T cell recognition of serially truncated peptides suggested that the mutated amino acid residue was a T cell receptor contact. Defining human tumor Ag recognized by T helper cells may provide important clues to designing more effective immunotherapies for cancer.

Cloning genes encoding MHC class II-restricted antigens: mutated CDC27 as a tumor antigen.

In an effort to identify tumor-specific antigens recognized by CD4(+) T cells, an approach was developed that allows the screening of an invariant chain-complementary DNA fusion library in a genetically engineered cell line expressing the essential components of the major histocompatibility complex (MHC) class II processing and presentation pathway. This led to the identification of a mutated form of human CDC27, which gave rise to an HLA-DR4-restricted melanoma antigen. A mutated form of triosephosphate isomerase, isolated by a biochemical method, was also identified as an HLA-DR1-restricted antigen. Thus, this approach may be generally applicable to the identification of antigens recognized by CD4(+) T cells, which could aid the development of strategies for the treatment of patients with cancer, autoimmune diseases, or infectious diseases.

MHC class II restricted tumor antigens and the role of CD4+ T cells in cancer immunotherapy.

Recent studies in human and murine systems suggest a central role for CD4+ T cells in initiating, effecting and maintaining anti-tumor immunity. Characterization of the tumor-associated antigens recognized by CD4+ T cells may prove critical to the success of cancer immunotherapy strategies.

The role of CD4+ T cell responses in antitumor immunity.

While most of the focus in cancer immunology is on CD8+ cytotoxic T lymphocyte responses, recent evidence indicates that CD4+ T cells are an equally critical component of the antitumor immune response. Successful immunity to cancer will therefore require activation of tumor-specific CD4+ T cells. Tumor antigens recognized by CD4+ T cells that are restricted by MHC class II are beginning to be defined in both murine and human tumors. These will provide the basis for new generations of antigen-specific tumor vaccines.

Identification and functional characterization of neo-poly(A) polymerase, an RNA processing enzyme overexpressed in human tumors.

Poly(A) polymerase (PAP) plays an essential role in polyadenylation of mRNA precursors, and it has long been thought that mammalian cells contain only a single PAP gene. We describe here the unexpected existence of a human PAP, which we call neo-PAP, encoded by a previously uncharacterized gene. cDNA was isolated from a tumor-derived cDNA library encoding an 82.8-kDa protein bearing 71% overall similarity to human PAP. Strikingly, the organization of the two PAP genes is nearly identical, indicating that they arose from a common ancestor. Neo-PAP and PAP were indistinguishable in in vitro assays of both specific and nonspecific polyadenylation and also endonucleolytic cleavage. Neo-PAP produced by transfection was exclusively nuclear, as demonstrated by immunofluorescence microscopy. However, notable sequence divergence between the C-terminal domains of neo-PAP and PAP suggested that the two enzymes might be differentially regulated. While PAP is phosphorylated throughout the cell cycle and hyperphosphorylated during M phase, neo-PAP did not show evidence of phosphorylation on Western blot analysis, which was unexpected in the context of a conserved cyclin recognition motif and multiple potential cyclin-dependent kinase (cdk) phosphorylation sites. Intriguingly, Northern blot analysis demonstrated that each PAP displayed distinct mRNA splice variants, and both PAP mRNAs were significantly overexpressed in human cancer cells compared to expression in normal or virally transformed cells. Neo-PAP may therefore be an important RNA processing enzyme that is regulated by a mechanism distinct from that utilized by PAP.

Prospective randomized trial of high-dose interleukin-2 alone or in conjunction with lymphokine-activated killer cells for the treatment of patients with advanced cancer.

BACKGROUND: Treatment using interleukin-2 (IL-2) alone or in conjunction with lymphokine-activated killer (LAK) cells has been shown to mediate disease regression in selected patients with advanced cancer. PURPOSE: This prospective randomized trial was designed to determine whether the administration of LAK cells in conjunction with high-dose IL-2 alters response and survival rates, compared with those for IL-2 alone, in patients with advanced cancer. METHODS: The 181 patients who had metastatic cancer that had failed to respond to standard therapy or who had disease for which no effective therapy existed received treatment with high-dose IL-2 alone or with LAK cells plus IL-2. Both treatment groups were to receive the same dose of IL-2 administered according to the same schedule. IL-2 doses were omitted depending on the tolerance of the patient. Of the 181 patients, 97 had renal cell cancer and 54 had melanoma. RESULTS: Median potential follow-up was 63.2 months. There were 10 complete responses among the 85 assessable patients who received IL-2 plus LAK cells, compared with four among the 79 who received IL-2 alone. There were 14 and 12 partial responses, respectively. Complete response continues in seven patients at 50-66 months. The 36-month actuarial survival with IL-2 plus LAK cells was 31%, compared with 17% with IL-2 alone (two-sided P value [P2] = .089). A trend toward improved survival was seen for patients with melanoma who received IL-2 plus LAK cells, compared with those who received IL-2 alone (24-month survival: 32% versus 15%; 48-month survival: 18% versus 4%; P2 = .064 [corrected]). None of 26 patients with melanoma who received IL-2 alone are alive; five of 28 who received IL-2 plus LAK cells are alive, and three continue in complete response. No difference in survival was seen in patients with renal cell cancer in the two treatment groups. There were six treatment-related deaths (3.3%); three were due to myocardial infarction. Other toxic effects resolved by discontinuation of IL-2. Many toxic effects were related to increased vascular permeability induced by IL-2. CONCLUSIONS: Some patients with metastatic cancer have prolonged remission when they are treated with high-dose IL-2 alone or in conjunction with LAK cells. Our results suggest a trend toward increased survival when IL-2 is given with LAK cells in patients with melanoma, but no trend was observed for patients with renal cell cancer. IMPLICATIONS: As these studies continue, efforts are underway to develop improved immunotherapies using tumor-infiltrating lymphocytes (TIL) and gene-modified TIL.

Treatment of patients with metastatic melanoma with autologous tumor-infiltrating lymphocytes and interleukin 2.

BACKGROUND: Studies of human tumor-infiltrating lymphocytes (TILs) derived from patients with a variety of histologic types of cancer have demonstrated that cellular immune reactions against established malignancy exist in humans. PURPOSE: We report the results of using autologous TILs plus high-dose bolus interleukin 2 (IL-2), with or without the concomitant administration of cyclophosphamide, in the treatment of 86 consecutive patients with metastatic melanoma. METHODS: From May 1987 through December 1992, 86 patients (38 female and 48 male) with metastatic melanoma were treated (145 courses) with autologous TILs plus high-dose intravenous bolus IL-2 (720,000 IU/kg every 8 hours). TILs plus IL-2 were administered in two cycles separated by approximately 2 weeks. Two treatment cycles constituted one treatment course. Patients received a maximum of 15 doses of IL-2 per cycle given every 8 hours until grade 3 or 4 toxicity was reached that could not easily be reversed by standard supportive measures. All patients received concomitant medications to abrogate some of the side effects of IL-2 administration: acetaminophen (650 mg every 4 hours), indomethacin (50 mg every 8 hours), and ranitidine (150 mg every 12 hours). Fifty-seven of the 86 patients received a single intravenous dose of 25 mg/kg cyclophosphamide approximately 36 hours before receiving the first intravenous infusion of TILs plus IL-2. Six weeks after treatment, all known sites of disease were evaluated. RESULTS: The overall objective response rate in these patients was 34% and was similar in patients receiving TILs and IL-2 alone (31%) or in conjunction with cyclophosphamide (35%). There was no significant difference in the objective response rate in patients whose therapy with high-dose IL-2 had failed (32%) compared with patients not previously treated with IL-2 (34%). The frequency of response to treatment was greater in those patients who were treated with TILs from younger cultures (P = .0001), TILs with shorter doubling times (P = .03), and TILs that exhibited higher lysis against autologous tumor targets (P = .0008). Patients who received TILs generated from subcutaneous tumor deposits had higher response rates (49%) compared with those receiving TILs from lymph nodes (17%; P = .006). There was one treatment-related death due to respiratory insufficiency. CONCLUSIONS: Treatment with TILs and IL-2 with or without cyclophosphamide can result in objective responses in about one third of patients with metastatic melanoma. The side effects of treatment are transient in most patients, and this treatment can be safely administered. These results illustrate the potential value of immune lymphocytes for the treatment of patients with melanoma.

Immunizing patients with metastatic melanoma using recombinant adenoviruses encoding MART-1 or gp100 melanoma antigens.

BACKGROUND: The characterization of the genes encoding melanoma-associated antigens MART-1 or gp100, recognized by T cells, has opened new possibilities for the development of immunization strategies for patients with metastatic melanoma. With the use of recombinant adenoviruses expressing either MART-1 or gp100 to immunize patients with metastatic melanoma, we evaluated the safety, immunologic, and potential therapeutic aspects of these immunizations. METHODS: In phase I studies, 54 patients received escalating doses (between 10(7) and 10(11) plaque-forming units) of recombinant adenovirus encoding either MART-1 or gp100 melanoma antigen administered either alone or followed by the administration of interleukin 2 (IL-2). The immunologic impact of these immunizations on the development of cellular and antibody reactivity was assayed. RESULTS: Recombinant adenoviruses expressing MART-1 or gp100 were safely administered. One of 16 patients with metastatic melanoma receiving the recombinant adenovirus MART-1 alone experienced a complete response. Other patients achieved objective responses, but they had received IL-2 along with an adenovirus, and their responses could be attributed to the cytokine. Immunologic assays showed no consistent immunization to the MART-1 or gp100 transgenes expressed by the recombinant adenoviruses. High levels of neutralizing antibody were found in the pretreatment sera of the patients. CONCLUSIONS: High doses of recombinant adenoviruses could be safely administered to cancer patients. High levels of neutralizing antibody present in patients' sera prior to treatment may have impaired the ability of these viruses to immunize patients against melanoma antigens.

Differential expression of MAGE-1, -2, and -3 messenger RNA in transformed and normal human cell lines.

The MAGE-1 gene codes for a tumor-specific antigen, MZ2-E, that elicited a cytotoxic T-lymphocyte response in the melanoma patient from whom it was derived. We have developed a simplified method, using polymerase chain reaction amplification of exon 3 followed by restriction enzyme pattern analysis, to distinguish expression of the MAGE-1 gene from MAGE-2 and MAGE-3, other members of this gene family. MAGE-1 mRNA was expressed in 53% of 17 melanoma lines, two of seven Epstein-Barr virus-transformed B-cell lines, and 2 of 5 breast cell lines including a line established form normal breast epithelium. MAGE-1 is not likely to be the common melanoma antigen recognized by the other HLA-A1- or HLA-A2-restricted cytotoxic T-lymphocytes examined in this study, but the fact that it is expressed in about 50% of melanoma cell lines makes it a reasonable target for the immunotherapy of patients bearing HLA-A1.

Quantitative correlation between HLA class I allele expression and recognition of melanoma cells by antigen-specific cytotoxic T lymphocytes.

MHC class I antigen expression is necessary for CD8+ T-cell-mediated recognition of tumors. Recently, several mechanisms leading to loss or decreased expression of MHC antigens on the tumor cell surface have been described that may account for tumor escape from immune recognition. It is yet unknown whether tumor recognition by CTL occurs at a threshold amount of MHC molecules or correlates with the level of HLA-allele expression. In this study, a model was developed in which clones derived from the 624-MEL melanoma cell line and expressing varying amounts of HLA-A2 molecules were lysed in a standard 51Cr release assay by an HLA-A2-restricted CTL clone (A42) or a bulk culture of tumor-infiltrating lymphocytes. The A42 clone and the tumor-infiltrating lymphocyte culture were characterized previously as specifically recognizing the melanoma antigen MART-1(27-35) peptide. A marked heterogeneity in the susceptibility to lysis by A42 was observed in tumor clones and was not due to heterogeneous expression of MART-1 by the clones or loss of accessory molecules involved in the lymphocyte-target interaction. Lysis by A42 and by the tumor-infiltrating lymphocyte culture significantly correlated with the level of HLA-A2 expression, evaluated as mean channel number of fluorescence by flow cytometry (P < 0.001). Transfection of an HLA-A2-negative clone (624.28) with the HLA-A2.1 gene produced a panel of clones expressing different levels of HLA-A2, the lysis of which was highly correlated with the expression of HLA-A2 (P < 0.001). The addition of exogenous MART-1(27-35) peptide enhanced lysis of clones expressing intermediate amounts of HLA-A2 but did not affect clones with high expression. These data suggest that the number of HLA molecules present on the surface of tumor cells can quantitatively affect their lysis by CTL in situations with borderline amounts of peptide and/or MHC.

Generation and genetic characterization of immortal human prostate epithelial cell lines derived from primary cancer specimens.

Difficulty in establishing long-term human prostate epithelial cell lines has impeded efforts to understand prostate tumorigenesis and to develop alternative therapies for prostate cancer. In the current study, we describe a method that was successful in generating 14 immortal benign or malignant prostate epithelial cell cultures from primary adenocarcinomas of the prostate resected from six successive patients. Immortalization with the E6 and E7 transforming proteins of human papilloma virus serotype 16 was necessary to establish long-term cultures. Microscopic examination of fresh tumor specimens exhibited a variable mixture of benign and malignant epithelium. Thus, single-cell cloning of tumor-derived cell cultures was essential for defining tumor cell lines. Efforts to characterize these cultures using traditional criteria such as karyotype, growth in nude mice, and prostate-specific antigen expression were noninformative. However, allelic loss of heterozygosity (LOH) represents a powerful alternative method for characterizing tumor cell lines originating from primary adenocarcinomas of the prostate. Microdissected fresh tumors from four of six patients revealed LOH at multiple loci on chromosome 8p, as assessed by PCR. LOH on chromosome 8p matching the patterns found in microdissected tumors was also observed in a tumor-derived cell line and its clones, as well as in one clone from a tumor-derived cell line from a second patient. LOH was not observed in immortal lines generated from autologous benign prostatic epithelium, seminal vesicle epithelium, or fibroblasts. The multifocal nature of prostate cancer, as well as the presence of an entire spectrum of malignant transformation within individual prostate glands, necessitates this type of careful analysis of derivative cell cultures for their validation as in vitro models that accurately reflect the primary cancers from which they are derived.

Infectious complications associated with interleukin-2 administration: a retrospective review of 935 treatment courses.

PURPOSE: To determine if interleukin-2 (IL-2)-treated patients are prone to develop clinically significant infections, a retrospective review of 519 patients who received 935 treatment courses over a 38-month period was conducted. MATERIALS AND METHODS: Treatment records of patients receiving intravenous (IV) bolus IL-2 were reviewed. Clinically significant infectious episodes were identified by retrieving data on antibiotic usage and cross-referencing this with microbiology records and chart review. RESULTS: One hundred thirty-nine documented infectious episodes occurred in 122 treatment courses (13.0%); 11 courses were associated with more than one episode of infection. Predominantly urinary tract infections (6.8%) and infections related to IV catheters (5.3%) were encountered. Fifty-eight percent of the catheter-related infections were associated with bacteremia. Other infections included respiratory tract infections (1.0%), skin/muscle infections (0.9%), and miscellaneous infections (0.9%). Bacteria were isolated from the majority of infections. Almost all patients were successfully treated for their infection, with only two septic deaths (0.2%). No difference was noted in infected versus non-infected patients with regard to diagnosis or previous therapy. There was a significant tendency for those patients who developed infection to be older (P2 = .002, Mantel test for trend). Risk factors for the development of infection included vascular access catheters, open wounds, biliary obstruction, or incomplete treatment of previous infections. Over the 3-year study period, the incidence of infection declined from 23% to 7% (P2 < .0001, Mantel test for trend) due to rigorous patient screening, vigilant monitoring for infection, liberal use of antibiotics for suspected infection, and use of prophylactic antibiotics for central venous catheter placement. CONCLUSION: Although treatment with IL-2 may be associated with a slightly increased incidence of bacterial infections, these infections can be successfully managed in the great majority of cases.

Clinical trial designs for the early clinical development of therapeutic cancer vaccines.

There are major differences between therapeutic tumor vaccines and chemotherapeutic agents that have important implications for the design of early clinical trials. Many vaccines are inherently safe and do not require phase I dose finding trials. Patients with advanced cancers and compromised immune systems are not good candidates for assessing either the toxicity or efficacy of therapeutic cancer vaccines. The rapid pace of development of new vaccine candidates and the variety of possible adjuvants and modifications in method of administration makes it important to use efficient designs for clinical screening and evaluation of vaccine regimens. We review the potential advantages of a wide range of clinical trial designs for the development of tumor vaccines. We address the role of immunological endpoints in early clinical trials of tumor vaccines, investigate the design implications of attempting to use disease stabilization as an end point and discuss the difficulties of reliably utilizing historical control data. Several conclusions for expediting the clinical development of effective cancer vaccines are proposed.

In vitro predictors of therapeutic response in melanoma patients receiving tumor-infiltrating lymphocytes and interleukin-2.

PURPOSE: To correlate in vitro characteristics of tumor-infiltrating lymphocytes (TIL) with clinical response to TIL immunotherapy in patients with metastatic melanoma. PATIENTS AND METHODS: Forty-one melanoma patients undergoing 43 separate treatment courses with TIL and interleukin-2 (IL-2) from December 1990 through November 1992 were studied prospectively. Multiple patient and treatment characteristics were evaluated for response correlates. In addition, TIL were assayed within 7 days of infusion for characteristics such as doubling time, cell-surface phenotype, autologous tumor lysis in 4-hour chromium-51 release assays, and cytokine secretion following autologous tumor stimulation. RESULTS: Nine patients experienced complete or partial tumor regressions. Clinical parameters such as age, sex, sites of disease, performance status, and prior therapies were similar in responders and nonresponders. Treatment variables such as the cumulative IL-2 dose and concomitant administration of cyclophosphamide or interferon (IFN)-alpha were not predictive of response, although responders received 33% more TIL. However, statistically significant differences in favor of clinical response were noted for extranodal source of TIL (v lymph node), shorter culture duration (mean, 38 v 47 days), shorter TIL doubling time (2.6 v 3.7 days), greater autologous tumor lysis by TIL (30% v 15%; effector-to-target [E:T], 40:1), and secretion of granulocyte-macrophage colony-stimulating factor (GM-CSF) by TIL following autologous tumor stimulation (six of nine responders v eight of 32 nonresponders). CONCLUSION: The associations of TIL lysis of autologous tumor and younger TIL age with clinical response observed in this study are supportive of previous reports, and these findings will be useful in designing future clinical trials. The new observation correlating GM-CSF secretion by TIL with clinical response is interesting and needs further substantiation.

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.

The use of interleukin-2 and lymphokine-activated killer cells for the treatment of patients with non-Hodgkin's lymphoma.

PURPOSE: The study was undertaken to assess whether immunotherapy regimens with bolus high-dose interleukin-2 (IL-2) alone or with lymphokine-activated killer (LAK) cells are active in previously treated, relapsed patients with non-Hodgkin's lymphoma. PATIENTS AND METHODS: Nineteen patients with low- or intermediate-grade lymphomas were treated with bolus high-dose IL-2 alone (11 patients) or IL-2 with LAK cells (eight patients). IL-2 was administered by intravenous bolus infusion at 720,000 IU/kg every 8 hours. Eight patients had low-grade histologies; 11 patients were intermediate-grade. Eighteen patients had received second- or third-generation combination chemotherapy, and eight had also received radiation. All 19 relapsed after a median of two chemotherapy regimens. RESULTS: Four responses were observed, three partial and one complete, in patients with follicular histologies who received IL-2 with LAK cells. Response durations were 10, 16, 16, and 26 months, and three responders were re-treated after relapse with subsequent disease control for an additional 16, 39+, and 2+ months, respectively. CONCLUSION: High-dose, bolus IL-2-based immunotherapy with LAK cells may be an effective treatment for patients with non-Hodgkin's lymphoma and merits further testing with larger numbers of patients in phase II trials.

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).