A progress report on the treatment of 157 patients with advanced cancer using lymphokine-activated killer cells and interleukin-2 or high-dose interleukin-2 alone

We studied the effects of adoptive immunotherapy with lymphokine-activated killer (LAK) cells plus interleukin-2 or therapy with high-dose interleukin-2 alone in 157 patients with metastatic cancer for whom standard therapy had proved ineffective or no standard effective treatment was available. One hundred eight patients were treated with 127 courses of LAK cells plus interleukin-2, and 49 patients were treated with 53 courses of high-dose interleukin-2 alone. Of 106 evaluable patients receiving LAK cells plus interleukin-2, 8 had complete responses, 15 had partial responses, and 10 had minor responses. The median duration of response was 10 months among those with complete responses and 6 months among those with partial responses; the patient with the longest complete response was still in remission 22 months after treatment. Of 46 evaluable patients treated with high-dose interleukin-2 alone, 1 had a complete response (remission greater than 4 months), 5 had partial responses (2, greater than 3, greater than 5, 7, and greater than 11 months), and 1 had a minor response. Seven of the total of nine complete responses still remain in remission. Hypotension, weight gain, oliguria, and elevation of bilirubin and creatinine levels were common, but these side effects resolved promptly after interleukin-2 administration was stopped. There have been four treatment-related deaths among these 157 patients. This immunotherapeutic approach can result in marked tumor regression in some patients for whom no other effective therapy is available at present. Determining its ultimate role in cancer therapy awaits further attempts to increase the therapeutic efficacy of treatment and decrease its toxicity and complexity.

Observations on the systemic administration of autologous lymphokine-activated killer cells and recombinant interleukin-2 to patients with metastatic cancer

We describe here the preliminary results of the systemic administration of autologous lymphokine-activated killer (LAK) cells and the recombinant-derived lymphokine interleukin-2 to patients with advanced cancer. This regimen was based on animal models in which the systemic administration of LAK cells plus interleukin-2 mediated the regression of established pulmonary and hepatic metastases from a variety of murine tumors in several strains of mice. We treated 25 patients with metastatic cancer in whom standard therapy had failed. Patients received both 1.8 to 18.4 X 10(10) autologous LAK cells, generated from lymphocytes obtained through multiple leukaphereses, and up to 90 doses of interleukin-2. Objective regression of cancer (more than 50 per cent of volume) was observed in 11 of the 25 patients: complete tumor regression occurred in one patient with metastatic melanoma and has been sustained for up to 10 months after therapy, and partial responses occurred in nine patients with pulmonary or hepatic metastases from melanoma, colon cancer, or renal-cell cancer and in one patient with a primary unresectable lung adenocarcinoma. Severe fluid retention was the major side effect of therapy, although all side effects resolved after interleukin-2 administration was stopped. Further development of this approach and additional patient follow-up are required before conclusions about its therapeutic value can be drawn.

Lymphokine-activated killer cell phenomenon. Lysis of natural killer-resistant fresh solid tumor cells by interleukin 2-activated autologous human peripheral blood lymphocytes

Activation in lectin-free interleukin 2 (IL-2) containing supernatants of peripheral blood mononuclear leukocytes (PBL) from cancer patients or normal individuals resulted in expression of cytotoxicity toward 20 of 21 natural killer (NK)-resistant fresh solid tumor cells tested. Fresh solid tumor cells were resistant to NK-mediated lysis in 10 autologous patients' PBL-tumor interactions, and from 17 normal individuals tested against 13 allogeneic fresh tumors. Culture of PBL in IL-2 for 2-3 d was required for the lymphokine activated killers (LAK) to be expressed, and lytic activity toward a variety of NK-resistant fresh and cultured tumor targets developed in parallel. Autologous IL-2 was functional in LAK activation, as well as interferon-depleted IL-2 preparations. Irradiation of responder PBL before culture in IL-2 prevented LAK development. Precursors of LAK were present in PBL depleted of adherent cells and in NK-void thoracic duct lymphocytes, suggesting that the precursor is neither a monocyte nor an NK cell. LAK effectors expressed the serologically defined T cell markers of OKT.3, Leu-1, and 4F2, but did not express the monocyte/NK marker OKM-1. Lysis of autologous fresh solid tumors by LAK from cancer patients' PBL was demonstrated in 85% of the patient-fresh tumor combinations. Our data present evidence that the LAK system is a phenomenon distinct from either NK or CTL systems that probably accounts for a large number of reported nonclassical cytotoxicities. The biological role of LAK cells is not yet known, although it is suggested that these cells may be functional in immune surveillance against human solid tumors.

Use of tumor-infiltrating lymphocytes and interleukin-2 in the immunotherapy of patients with metastatic melanoma. A preliminary report

Lymphocytes extracted from freshly resected melanomas can be expanded in vitro and can often mediate specific lysis of autologous tumor cells but not allogeneic tumor or autologous normal cells. We treated 20 patients with metastatic melanoma by means of adoptive transfer of these tumor-infiltrating lymphocytes and interleukin-2, after the patients had received a single intravenous dose of cyclophosphamide. Objective regression of the cancer was observed in 9 of 15 patients (60 percent) who had not previously been treated with interleukin-2 and in 2 of 5 patients (40 percent) in whom previous therapy with interleukin-2 had failed. Regression of cancer occurred in the lungs, liver, bone, skin, and subcutaneous sites and lasted from 2 to more than 13 months. Toxic effects of interleukin-2 occurred, although the treatment course was short (five days); these side effects were reversible. It appears that in patients with metastatic melanoma, this experimental treatment regimen can produce higher response rates than those achieved with interleukin-2 administered alone or with lymphokine-activated killer cells. It is too early to determine whether this new form of immunotherapy can improve survival, but further trials seem warranted.

High-dose recombinant interleukin 2 therapy for patients with metastatic melanoma: analysis of 270 patients treated between 1985 and 1993

PURPOSE

To determine the short- and long-term efficacy and toxicity of the high-dose intravenous bolus interleukin 2 (IL-2) regimen in patients with metastatic melanoma.

PATIENTS AND METHODS

Two hundred seventy assessable patients were entered onto eight clinical trials conducted between 1985 and 1993. IL-2 (Proleukin [aldesleukin]; Chiron Corp, Emeryville, CA) 600,000 or 720,000 IU/kg was administered by 15-minute intravenous infusion every 8 hours for up to 14 consecutive doses over 5 days as clinically tolerated with maximum support, including pressors. A second identical treatment cycle was scheduled after 6 to 9 days of rest, and courses could be repeated every 6 to 12 weeks in stable or responding patients. Data were analyzed through fall 1996.

RESULTS

The overall objective response rate was 16% (95% confidence interval, 12% to 21%); there were 17 complete responses (CRs) (6%) and 26 partial responses (PRs) (10%). Responses occurred with all sites of disease and in patients with large tumor burdens. The median response duration for patients who achieved a CR has not been reached and was 5.9 months for those who achieved a PR. Twelve (28%) of the responding patients, including 10 (59%) of the patients who achieved a CR, remain progression-free. Disease did not progress in any patient responding for more than 30 months. Baseline performance status and whether patients had received prior systemic therapy were the only predictive prognostic factors for response to IL-2 therapy. Toxicities, although severe, generally reversed rapidly after therapy was completed. Six patients (2%) died from adverse events, all related to sepsis.

CONCLUSION

High-dose IL-2 treatment seems to benefit some patients with metastatic melanoma by producing durable CRs or PRs and should be considered for appropriately selected melanoma patients.

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.

A new approach to the adoptive immunotherapy of cancer with tumor-infiltrating lymphocytes

The adoptive transfer of tumor-infiltrating lymphocytes (TIL) expanded in interleukin-2 (IL-2) to mice bearing micrometastases from various types of tumors showed that TIL are 50 to 100 times more effective in their therapeutic potency than are lymphokine-activated killer (LAK) cells. Therefore the use of TIL was explored for the treatment of mice with large pulmonary and hepatic metastatic tumors that do not respond to LAK cell therapy. Although treatment of animals with TIL alone or cyclophosphamide alone had little impact, these two modalities together mediated the elimination of large metastatic cancer deposits in the liver and lung. The combination of TIL and cyclophosphamide was further potentiated by the simultaneous administration of IL-2. With the combination of cyclophosphamide, TIL, and IL-2, 100% of mice (n = 12) bearing the MC-38 colon adenocarcinoma were cured of advanced hepatic metastases, and up to 50% of mice were cured of advanced pulmonary metastases. Techniques have been developed to isolate TIL from human tumors. These experiments provide a rationale for the use of TIL in the treatment of humans with advanced cancer.

Randomized prospective study of the benefit of adjuvant radiation therapy in the treatment of soft tissue sarcomas of the extremity

PURPOSE

This randomized, prospective study assesses the impact of postoperative external-beam radiation therapy on local recurrence (LR), overall survival (OS), and quality of life after limb-sparing resection of extremity sarcomas.

PATIENTS AND METHODS

Patients with extremity tumors and a limb-sparing surgical option were randomized to receive or not receive postoperative adjuvant external-beam radiotherapy. Patients with high-grade sarcomas received postoperative adjuvant chemotherapy whereas patients with low-grade sarcomas or locally aggressive nonmalignant tumors were randomized after surgery alone.

RESULTS

Ninety-one patients with high-grade lesions were randomized; 47 to receive radiotherapy (XRT) and 44 to not receive XRT. With a median follow-up of 9.6 years, a highly significant decrease (P2 = .0028) in the probability of LR was seen with radiation, but no difference in OS was shown. Of 50 patients with low-grade lesions (24 randomized to resection alone and 26 to resection and postoperative XRT), there was also a lower probability of LR (P2 = .016) in patients receiving XRT, again, without a difference in OS. A concurrent quality-of-life study showed that extremity radiotherapy resulted in significantly worse limb strength, edema, and range of motion, but these deficits were often transient and had few measurable effects on activities of daily life or global quality of life.

CONCLUSION

This study indicates that although postoperative external-beam radiotherapy is highly effective in preventing LRs, selected patients with extremity soft tissue sarcoma who have a low risk of LR may not require adjuvant XRT after limb-sparing surgery (LSS).

Report of a committee convened to discuss the evaluation and staging of patients with Hodgkin's disease: Cotswolds meeting

The Ann Arbor classification for describing the stage of Hodgkin's disease at initial presentation has formed the basis upon which treatment is selected and has allowed comparison of results achieved by different investigators for almost two decades. A meeting was convened to review the classification and modify it in the light of experience gained in its use and new techniques for evaluating disease. It was concluded that the structure of the classification be maintained. It was particularly recommended: (1) that computed tomography (CT) be included as a technique for evaluating intrathoracic and infradiaphragmatic lymph nodes; (2) that the criteria for clinical involvement of the spleen and liver be modified to include evidence of focal defects with two imaging techniques and that abnormalities of liver function be ignored; (3) that the suffix 'X' to designate bulky disease (greater than 10 cm maximum dimension) be introduced; and (4) that a new category of response to therapy, unconfirmed/uncertain complete remission (CR[u]), be introduced to accommodate the difficulty of persistent radiological abnormalities of uncertain significance.

Results of treatment of 255 patients with metastatic renal cell carcinoma who received high-dose recombinant interleukin-2 therapy

PURPOSE

To determine the efficacy and toxicity of a high-dose interleukin-2 (IL-2) regimen in patients with metastatic renal cell carcinoma.

PATIENTS AND METHODS

Two hundred fifty-five assessable patients were entered onto seven phase II clinical trials. Proleukin (aldesleukin; Chiron Corp, Emeryville, CA) 600,000 or 720,000 IU/kg was administered by 15-minute intravenous (i.v.) infusion every 8 hours for up to 14 consecutive doses over 5 days as clinically tolerated with maximum support, including pressors. A second identical cycle of treatment was scheduled following 5 to 9 days of rest, and courses could be repeated every 6 to 12 weeks in stable or responding patients.

RESULTS

The overall objective response rate was 14% (90% confidence interval [CI], 10% to 19%), with 12 (5%) complete responses (CRs) and 24 (9%) partial responses (PRs). Responses occurred in all sites of disease, including bone, intact primary tumors, and visceral metastases, and in patients with large tumor burdens or bulky individual lesions. The median response duration for patients who achieved a CR has not been reached, but was 19.0 months for those who achieved a PR. Baseline Eastern Cooperative Oncology Group (ECOG) performance status (PS) was the only predictive prognostic factor for response to IL-2. While treatment was associated with severe acute toxicities, these generally reversed rapidly after therapy was completed. However, 4% of patients died of adverse events judged to be possibly or probably treatment-related.

CONCLUSION

High-dose IL-2 appears to benefit some patients with metastatic renal cell carcinoma by producing durable CRs or PRs. Despite severe acute treatment-associated toxicities, IL-2 should be considered for initial therapy of patients with appropriately selected metastatic renal cell carcinoma.

The treatment of soft-tissue sarcomas of the extremities: prospective randomized evaluations of (1) limb-sparing surgery plus radiation therapy compared with amputation and (2) the role of adjuvant chemotherapy

Between May 1975 and April 1981, 43 adult patients with high-grade soft tissue sarcomas of the extremities were prospectively randomized to receive either amputation at or above the joint proximal to the tumor, including all involved muscle groups, or to receive a limb-sparing resection plus adjuvant radiation therapy. The limb-sparing resection group received wide local excision followed by 5000 rads to the entire anatomic area at risk for local spread and 6000 to 7000 rads to the tumor bed. Both randomization groups received postoperative chemotherapy with doxorubicin (maximum cumulative dose 550 mg/m2), cyclophosphamide, and high-dose methotrexate. Twenty-seven patients randomized to receive limb-sparing resection and radiotherapy, and 16 received amputation (randomization was 2:1). There were four local recurrences in the limb-sparing group and none in the amputation group (p1 = 0.06 generalized Wilcoxon test). However, there were no differences in disease-free survival rates (71% and 78% at five years; p2 = 0.75) or overall survival rates (83% and 88% at five years; p2 = 0.99) between the limb-sparing group and the amputation treatment groups. Multivariate analysis indicated that the only correlate of local recurrence was the final margin of resection. Patients with positive margins of resection had a higher likelihood of local recurrence compared with those with negative margins (p1 less than 0.0001) even when postoperative radiotherapy was used. A simultaneous prospective randomized study of postoperative chemotherapy in 65 patients with high-grade soft-tissue sarcomas of the extremities revealed a marked advantage in patients receiving chemotherapy compared with those without chemotherapy in three-year continuous disease-free (92% vs. 60%; p1 = 0.0008) and overall survival (95% vs. 74%; p1 = 0.04). Thus limb-sparing surgery, radiation therapy, and adjuvant chemotherapy appear capable of successfully treating the great majority of adult patients with soft tissue sarcomas of the extremity.

Progress in human tumour immunology and immunotherapy

Studies of the administration of interleukin-2 to patients with metastatic melanoma or kidney cancer have shown that immunological manipulations can mediate the durable regression of metastatic cancer. The molecular identification of cancer antigens has opened new possibilities for the development of effective immunotherapies for patients with cancer. Clinical studies using immunization with peptides derived from cancer antigens have shown that high levels of lymphocytes with anti-tumour activity can be raised in cancer-bearing patients. Highly avid anti-tumour lymphocytes can be isolated from immunized patients and grown in vitro for use in cell-transfer therapies. Current studies are aimed at understanding the mechanisms that enable the cancer to escape from immune attack.

T lymphocyte-directed gene therapy for ADA- SCID: initial trial results after 4 years

In 1990, a clinical trial was started using retroviral-mediated transfer of the adenosine deaminase (ADA) gene into the T cells of two children with severe combined immunodeficiency (ADA- SCID). The number of blood T cells normalized as did many cellular and humoral immune responses. Gene treatment ended after 2 years, but integrated vector and ADA gene expression in T cells persisted. Although many components remain to be perfected, it is concluded here that gene therapy can be a safe and effective addition to treatment for some patients with this severe immunodeficiency disease.

Gene transfer into humans--immunotherapy of patients with advanced melanoma, using tumor-infiltrating lymphocytes modified by retroviral gene transduction

BACKGROUND AND METHODS

Treatment with tumor-infiltrating lymphocytes (TIL) plus interleukin-2 can mediate the regression of metastatic melanoma in approximately half of patients. To optimize this treatment approach and define the in vivo distribution and survival of TIL, we used retroviral-mediated gene transduction to introduce the gene coding for resistance to neomycin into human TIL before their infusion into patients--thus using the new gene as a marker for the infused cells.

RESULTS

Five patients received the gene-modified TIL. All the patients tolerated the treatment well, and no side effects due to the gene transduction were noted. The presence and expression of the neomycin-resistance gene were demonstrated in TIL from all the patients with Southern blot analysis and enzymatic assay for the neomycin phosphotransferase coded by the bacterial gene. Cells from four of the five patients grew successfully in high concentrations of G418, a neomycin analogue otherwise toxic to eukaryotic cells. With polymerase-chain-reaction analysis, gene-modified cells were consistently found in the circulation of all five patients for three weeks and for as long as two months in two patients. Cells were recovered from tumor deposits as much as 64 days after cell administration. The procedure was safe according to all criteria, including the absence of infections virus in TIL and in the patients.

CONCLUSIONS

These studies demonstrate the feasibility and safety of using retroviral gene transduction for human gene therapy and have implications for the design of TIL with improved antitumor potency, as well as for the possible use of lymphocytes for the gene therapy of other diseases.

Cloning of the gene coding for a shared human melanoma antigen recognized by autologous T cells infiltrating into tumor

By cDNA expression cloning we have isolated a gene encoding a shared human melanoma antigen recognized by HLA-A2 restricted autologous and allogenic tumor-infiltrating lymphocytes (TILs) from patients with metastatic melanoma. By using both transient and stable expression systems, transfection of this gene into non-antigen-expressing HLA-A2+ cell lines resulted in recognition by the antigen-specific TILs. The sequence of this cDNA revealed a previously undescribed putative transmembrane protein whose expression was restricted to melanoma and melanocyte cell lines and human retina but no other fresh or cultured normal tissues tested or other tumor histologies. Thus, we have identified a gene encoding a melanocyte lineage-specific protein (MART-1; melanoma antigen recognized by T cells 1) that is a widely shared melanoma antigen recognized by the T lymphocytes of patients with established malignancy. Identification of this gene opens possibilities for the development of immunotherapies for patients with melanoma.

Experience with the use of high-dose interleukin-2 in the treatment of 652 cancer patients

We have administered 1039 courses of high-dose interleukin-2 (IL-2) to 652 cancer patients. Five hundred ninety-six patients had metastatic cancer that either had failed standard effective therapies or had disease for which no standard effective therapy existed, and 56 patients were treated in the absence of evaluable disease in the adjuvant setting. IL-2 was administered either alone (155 patients) or in conjunction with activated immune cells such as lymphokine activated killer (LAK) cells (214 patients) or tumor infiltrating lymphocytes (TIL) (66 patients), with other cytokines such as alpha interferon (a-IFN)(128 patients) or tumor necrosis factor (TNF)(38 patients), with monoclonal antibodies (32 patients), or with the chemotherapeutic agent cyclophosphamide (19 patients). Initial results with the treatment of high-dose IL-2 alone or in conjunction with LAK cells have indicated that objective regressions of cancer can be achieved in 20% to 35% of patients with selected advanced metastatic cancers. Although most responses have been seen in patients with metastatic renal cell cancer, melanoma, colorectal cancer, and non-Hodgkin's lymphoma, many histologic types of cancer have not been treated in significant numbers. These regressions can be durable; of 18 patients achieving a complete response, ten have not experienced recurrence at intervals from 18 to 52 months. Although combinations of IL-2 with TNF do not appear to result in increased responses, there is a suggestion in our initial phase I studies that the combination of a-IFN and IL-2 is more effective than the administration of cytokine alone and this combination deserves further study. Similarly the adoptive transfer of TIL in conjunction with IL-2 also appears to be more effective than the use of IL-2 alone. The toxic side effects in patients treated with high-dose IL-2 are presented and include malaise, nausea and vomiting, hypotension, fluid retention, and organ dysfunction. Treatment-related deaths were seen in 1% of all treatment courses and in 1.5% of patients. These studies demonstrate that a purely immunologic manipulation can mediate the regression of advanced cancers in selected patients and may provide a base for the development of practical, effective biologic treatments for some cancer patients.

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.

Identification of a human melanoma antigen recognized by tumor-infiltrating lymphocytes associated with in vivo tumor rejection

The cultured T-cell line TIL1200, established from the tumor-infiltrating lymphocytes (TILs) of a patient with advanced metastatic melanoma, recognized an antigen on most HLA-A2+ melanomas and on all HLA-A2+ cultured neonatal melanocytes in an HLA-A2 restricted manner but not on other types of tissues or cell lines tested. A cDNA encoding an antigen recognized by TIL1200 was isolated by screening an HLA-A2+ breast cancer cell line transfected with an expression cDNA library prepared from an HLA-A2+ melanoma cell line. The nucleotide and amino acid sequences of this cDNA were almost identical to the genes encoding glycoprotein gp100 or Pmel17 previously registered in the GenBank. Expression of this gene was restricted to melanoma and melanocyte cell lines and retina but was not expressed on other fresh or cultured normal tissues or other types of tumor tested. The cell line transfected with this cDNA also expressed antigen recognized by the melanoma-specific antibody HMB45 that bound to gp100. A synthetic 10-amino acid peptide derived from gp100 was recognized by TIL1200 in the context of HLA-A2.1. Since the administration of TIL1200 plus interleukin 2 resulted in regression of metastatic cancer in the autologous patient, gp100 is a possible tumor rejection antigen and may be useful for the development of immunotherapies for patients with melanoma.

The natural history of initially untreated low-grade non-Hodgkin's lymphomas

To learn more about the natural history of low-grade non-Hodgkin's lymphoma, we have studied 83 patients in whom the advanced disease was initially managed without therapy. Actuarial survival was 82 per cent at 5 years and 73 per cent at 10 years. The median time until therapy was required was three years. Spontaneous regressions occurred in 19 untreated patients (23 per cent), including 30 per cent of patients with nodular, poorly differentiated lymphocytic lymphoma. Histologic transformation to an intermediate-grade or high-grade lymphoma occurred both before and after primary therapy. The actuarial risk of transformation among the initially untreated patients was similar to that in a group of patients treated at this institution immediately after diagnosis. Neither the time to histologic transformation nor the incidence of transformation was influenced by when therapy was started.

Identification of the immunodominant peptides of the MART-1 human melanoma antigen recognized by the majority of HLA-A2-restricted tumor infiltrating lymphocytes

Four melanoma proteins, MART-1, gp100, tyrosinase, and tyrosinase-related protein-1 (gp75) were evaluated for recognition by HLA-A2-restricted melanoma-specific cytotoxic T lymphocytes (CTLs) derived from the tumor-infiltrating lymphocytes (TIL) of 10 different patients. 9 of 10 TIL recognized MART-1, 4 recognized gp100 (including 3 that also recognized MART-1), but none of the TIL recognized tyrosinase or gp75. Based on the known HLA-A2.1 peptide binding motifs, 23 peptides from MART-1 were synthesized in an attempt to identify the epitopes recognized by TIL. Three peptides were recognized by TIL when pulsed on T2 target cells. One of the 9-mer peptides, AAGIGILTV, was most effective in sensitizing the T2 cells for TIL lysis. This peptide was recognized by 9 of 10 HLA-A2-restricted melanoma-specific CTLs. Therefore, this peptide appears to be a very common immunogenic epitope for HLA-A2-restricted melanoma-specific TIL and may be useful for the development of immunotherapeutic strategies.

Risk of second cancers after treatment for Hodgkin's disease

We estimated the risk of second cancers among 1507 patients with Hodgkin's disease treated at Stanford University Medical Center since 1968. Eight-three second cancers occurred more than one year after diagnosis, as compared with 15.9 expected on the basis of rates in the general population (relative risk, 5.2; 95 percent confidence interval, 4.2 to 6.5). The mean (+/- SE) 15-year actuarial risk of all second cancers was 17.6 +/- 3.1 percent, of which 13.2 +/- 3.1 percent was due to solid tumors. The risk of leukemia appeared to reach a plateau level of 3.3 +/- 0.6 percent at 10 years, whereas non-Hodgkin's lymphoma continued to increase, to 1.6 +/- 0.7 percent by the end of the follow-up period. The risk of solid tumors did not vary significantly according to treatment category, with the array of neoplasms resembling that previously observed in populations exposed to radiation and in immunosuppressed groups. The risk of leukemia, although elevated after radiation therapy alone (relative risk, 11; 95 percent confidence interval, 1.2 to 38), was much higher after either adjuvant chemotherapy (relative risk, 117; 95 percent confidence interval, 69 to 185) or chemotherapy alone (relative risk, 130; 95 percent confidence interval, 26 to 380). These data suggest that the risk of solid tumors after therapy for Hodgkin's disease continues to increase with time.

Regression of established pulmonary metastases and subcutaneous tumor mediated by the systemic administration of high-dose recombinant interleukin 2

Incubation of resting lymphoid cells with recombinant interleukin 2 (IL-2) in vitro leads to the generation of lymphokine activated killer (LAK) cells capable of lysing fresh tumor cell suspensions in short-term chromium-release assays. Our previous studies (7) have demonstrated that the injection of LAK cells plus low doses of recombinant IL-2 were capable of inhibiting the growth of pulmonary metastases. We have now explored the ability of high doses of recombinant IL-2, administered systemically, to generate LAK cells in vivo, and to mediate antitumor effects directly. Administration of increasing doses of recombinant IL-2 intraperitoneally resulted in the generation of LAK cells in the spleens of recipient mice. Doses of 100,000 U recombinant IL-2 administered intraperitoneally approximately every 8 h for 5 d were capable of dramatically inhibiting established 3-d pulmonary metastases from the MCA-105 and MCA-106 syngeneic sarcomas and the syngeneic B16 melanoma in C57BL/6 mice. Grossly visible metastases present at 10 d after tumor injection also underwent regression following IL-2 therapy. Surprisingly, established 10 d pulmonary metastases were more susceptible to the effects of IL-2 than were the smaller 3 d pulmonary metastases. All antitumor effects of the systemic administration of recombinant IL-2 were eliminated if mice received prior treatment with 500 rad total body irradiation. The administration of high doses of recombinant IL-2 was also capable of inhibiting the growth of 3-d established subcutaneous tumors from the MCA-105 sarcoma, and of mediating the inhibition of growth and regression of established palpable subcutaneous MCA-105 sarcomas. Lymphocytes, which appeared morphologically to be activated, were present at the site of regressing tumor, and it appears that the mechanism of the antitumor effect of recombinant IL-2 administered systemically is via the generation of LAK cells in vivo, although this hypothesis remains to be proven. The ready availability of high doses of recombinant human IL-2, and the demonstration of antitumor effects seen in animal models have led us to the initiation of the clinical trials of recombinant IL-2 in humans.

Identification of human cancers deficient in antigen processing

Intracellular antigens must be processed before presentation to CD8+ T cells by major histocompatibility complex (MHC) class I molecules. Using a recombinant vaccinia virus (Vac) to transiently express the Kd molecule, we studied the antigen processing efficiency of 26 different human tumor lines. Three cell lines, all human small cell lung carcinoma, consistently failed to process endogenously synthesized proteins for presentation to Kd-restricted, Vac-specific T cells. Pulse-chase experiments showed that MHC class I molecules were not transported by these cell lines from the endoplasmic reticulum to the cell surface. This finding suggested that peptides were not available for binding to nascent MHC molecules in the endoplasmic reticulum. Northern blot analysis of these cells revealed low to nondetectable levels of mRNAs for MHC-encoded proteasome components LMP-7 and LMP-2, as well as the putative peptide transporters TAP-1 and TAP-2. Treatment of cells with interferon gamma enhanced expression of these mRNAs and reversed the observed functional and biochemical deficits. Our findings suggest that downregulation of antigen processing may be one of the strategies used by tumors to escape immune surveillance. Potential therapeutic applications of these findings include enhancing antigen processing at the level of the transcription of MHC-encoded proteasome and transporter genes.

Adoptive immunotherapy of established pulmonary metastases with LAK cells and recombinant interleukin-2

The activation of human peripheral blood leukocytes or murine splenocytes with interleukin-2 (IL-2) generated cells that were lytic in vitro for a variety of fresh tumor cells. The adoptive transfer of such lymphokine-activated killer (LAK) cells to mice with established pulmonary sarcoma metastases was highly effective in reducing the number (and size) of these tumor nodules when combined with repeated injections of recombinant IL-2. These findings provide a rationale for clinical trials of the infusion of human LAK cells generated with recombinant IL-2 as well as Phase I trials of the infusion of recombinant IL-2 systemically into humans.