Postremission therapy in older patients with de novo acute myeloid leukemia: a randomized trial comparing mitoxantrone and intermediate-dose cytarabine with standard-dose cytarabine.

The treatment of older patients with acute myeloid leukemia (AML) remains unsatisfactory, with complete remission (CR) achieved in only approximately 50% and long-term disease-free survival in 10% to 20%. Three hundred eighty-eight patients (60 years of age and older) with newly diagnosed de novo AML were randomly assigned to receive placebo (P) or granulocyte-macrophage colony-stimulating factor (GM-CSF) or GM in a double-blind manner, beginning 1 day after the completion of 3 days of daunorubicin and 7 days of cytarabine therapy. No differences were found in the rates of leukemic regrowth, CR, or infectious complications in either arm. Of 205 patients who achieved CR, 169 were medically well and were randomized to receive cytarabine alone or a combination of cytarabine and mitoxantrone. With a median follow-up of 7.7 years, the median disease-free survival times were 11 months and 10 months for those randomized to cytarabine or cytarabine/mitoxantrone, respectively. Rates of relapse, excluding deaths in CR, were 77% for cytarabine and 82% for cytarabine/mitoxantrone. Induction randomization had no effect on leukemic relapse rate or remission duration in either postremission arm. Because cytarabine/mitoxantrone was more toxic and no more effective than cytarabine, it was concluded that this higher-dose therapy had no benefit in the postremission management of older patients with de novo AML. These results suggest the need to develop novel therapeutic strategies for these patients. (Blood. 2001;98:548-553)

Interleukin-2 plus chemotherapy for patients with metastatic melanoma.

We studied the activity of recombinant interleukin-2 (IL2) in combination with multiagent chemotherapy in the treatment of patients with disseminated malignant melanoma. Patients were randomized to receive the same dose of lymphokine by constant 24 h intravenous infusion (CI) or by subcutaneous bolus (SB) injection. Twenty-two patients, 18 males and four females with a median age of 44 years (range 32-73 years) were randomized to receive IL2 5 million units/m2 once daily by SB injection or by CI, 5 days/week for 2 weeks. All patients received a chemotherapy regimen consisting of lomustine (CCNU) 75 mg/m2 on day 14, bleomycin 10 units/day by CI for 5 days (days 14-19) and cisplatin 75 mg/m2 on day 19. Patients were retreated after a 3 week interval. There were four complete responses and one partial response in the CI arm and two partial responses in the SB arm. The median duration of response was 38 weeks (range 26-107 weeks). The median duration of survival was 6.7 months in non-responders and 11.1 months in responders. The overall response rate was 32%. Since responses were brief and all the responding patients progressed after a median of 38 weeks, the study was terminated before accrual goals were met.

An evaluation of combinations of diaziquone, etoposide and mitoxantrone in the treatment of adults with relapsed or refractory acute myeloid leukemia: results of 8722, a randomized phase II study conducted by Cancer and Leukemia Group B.

A phase II trial was conducted to determine which of the three possible two-drug combinations of diaziquone, etoposide and mitoxantrone was associated with the highest response rate in patients with relapsed or refractory acute myeloid leukemia (AML). Of the 167 patients (median age 55) with AML who entered the trial, 123 were in first relapse, 22 were in second relapse and 22 had failed to achieve complete remission (CR). CR rates were 30% for diaziquone and mitoxantrone, and 23% for the other two combinations (mitoxantrone/etoposide and diaziquone/etoposide), NS. Patients in first relapse had higher CR rates (40%) than other patients. Of the 166 patients who actually received treatment, 43 died before having either a CR or persistent leukemia. Non-hematologic toxicity was primarily mucosal with 24% of patients experiencing grade 3 or greater stomatitis on the two diaziquone arms, and 43% on the mitoxantrone/etoposide arm. The combination of diaziquone and mitoxantrone was selected for further testing in patients with AML.

Sequential mitoxantrone, daunorubicin, and cytosine arabinoside for patients with newly diagnosed acute myelocytic leukemia.

Mitoxantrone (M) is a synthetic aminoanthraquinone with anti-leukemic activity in patients with daunorubicin (D) resistant acute leukemia. The Cancer and Leukemia Group B (CALGB) has undertaken a limited access pilot study in which M, 12 mg/m2, over 30 min, daily for 3 days, and cytosine arabinoside (Ara-C), 100 mg/m2/day by constant infusion for 7 days were used for the induction of newly diagnosed patients with AML. Responding patients were consolidated with daunorubicin, 45 mg/m2/day for 3 days, and 7 days of Ara-C. After a second consolidation identical to induction, no further therapy was given. Twenty-nine patients with a median age of 50 years (range 18-72) were entered in the study; 18 were males and 11 females. Twenty-four (83%) patients achieved CR, 1 patient achieved a PR, and 4 died in induction from leukemia-related causes. Two patients died in CR from consolidation-related neutropenic sepsis and two additional patients died in CR. Of 24 patients, 7 remain disease-free at a median follow-up interval of 8 years. The regimen is active and well tolerated. The duration of disease-free survival in responding patients is consistent with that seen in similar regimens using intensification chemotherapy without prolonged maintenance.

Surgical treatment of spinal cord compression from epidural metastasis.

PURPOSE: A retrospective study of the results of neoplastic cord compression was undertaken to determine the effectiveness of surgical treatment and to assess quality of life in patients undergoing extensive procedures with potential morbidity. PATIENTS AND METHODS: Over a 5-year period (1989 to 1993), a total of 110 patients underwent surgery. Fifty-five patients (50%) had undergone prior treatment, including 47 (43%) who had failed to respond to prior irradiation (RT). Before surgery, 48 patients (44%) were nonambulatory, with severe paresis being present in 20. Surgery included staged anterior-posterior resections in 53 patients (48%), anterior resections in 33 (30%), and posterior resection in six (5%), all of whom required spinal instrumentation for reconstruction; only 18 patients underwent resection without instrumentation. RESULTS: Postoperatively, 90 patients (82%) were improved, both in terms of pain relief and ambulatory status. Fifty-three patients (48%) experienced postoperative complications, related statistically to the following three factors: age over 65 years, prior treatment, and presence of paraparesis. The overall median survival duration was 16 months, with 46% alive at 2 years. Apart from primary tumor, the presence of preoperative paraparesis had the most significant impact on survival. CONCLUSION: Our data suggest that the effective surgical treatment of neoplastic compression requires anterior-posterior resection in most patients to achieve the goal of total tumor resection, with the majority requiring instrumentation. Long-term survival is feasible in a subset of patients with this aggressive surgical approach.

Granulocyte-macrophage colony-stimulating factor after initial chemotherapy for elderly patients with primary acute myelogenous leukemia. Cancer and Leukemia Group B.

BACKGROUND: Elderly patients with primary acute myelogenous leukemia (AML) are less likely to enter remission than younger adults, in part because of a higher mortality rate related to severe myelosuppression. Granulocyte-macrophage colony-stimulating factor (GM-CSF) has been shown to shorten the duration of neutropenia and decrease infectious complications when administered after chemotherapy to patients with lymphomas and solid tumors. METHODS: We randomly assigned 388 patients 60 years of age or older who had newly diagnosed primary AML to receive placebo or GM-CSF (5 micrograms per kilogram of body weight per day intravenously over a period of six hours) in a double-blind manner, beginning the day after the completion of three days of daunorubicin (45 mg per square meter of body-surface area per day) and seven days of cytarabine (200 mg per square meter per day by continuous intravenous infusion). If leukemia cells persisted in the marrow three weeks after the initiation of chemotherapy, further daunorubicin (two days) and cytarabine (five days) were administered. GM-CSF or placebo was given daily until the neutrophil count was at least 1000 per cubic millimeter, there was evidence of the regrowth of leukemia, or severe toxic effects attributable to the study infusion occurred. Patients who had a complete remission were then randomly assigned to receive one of two intensification regimens. RESULTS: Of 388 patients (median age, 69 years), 193 were randomly assigned to receive GM-CSF and 195 to placebo. The rate of complete remission was 51 percent (95 percent confidence interval, 44 to 59 percent) among those assigned to GM-CSF and 54 percent (95 percent confidence interval, 47 to 61 percent) among those assigned to receive placebo (P = 0.61). The reasons for failure (early death, death during marrow hypoplasia, and persistent leukemia), the incidence of severe or lethal infection, and the incidence of the regrowth of leukemia (2 percent overall) were similar in the two groups. The median duration of neutropenia was slightly shorter (P = 0.02) in the patients who received GM-CSF (15 days) than in those who received placebo (17 days), but the clinical importance of this result was minimal because the growth factor failed to lower the treatment-related mortality rate or improve the rate of complete remission. CONCLUSIONS: GM-CSF, in the dose and schedule we used, does not stimulate the regrowth of leukemia, but it also does not decrease the severe myelosuppressive consequences of initial chemotherapy or improve the response rate in patients 60 years of age or older with primary AML. It should not be recommended for use in such patients.

Increase of plasma transforming growth factor beta (TGF beta) during immunotherapy with IL-2.

Interleukin-2 (IL-2) is a lymphokine with pleiotropic activities on the immune system. When administered in vivo, besides inducing unrestricted tumor cytotoxicity, it is also responsible for the secondary release of other lymphokines, such as IL-1, TNF, and marrow growth factors, which may mediate some of the clinical toxicities (as well as therapeutic effects) seen during IL-2 immunotherapy. Among the clinical effects of IL-2, we previously reported thrombocytopenia and IL-2-induced in vitro inhibition of platelet aggregation accompanied by rapid secretion of alpha-granule components such as platelet factor 4 (PF4) and beta-thromboglobulin. Platelets constitute one of the largest storage forms of TGF beta. Preliminary evaluation of this factor in patients receiving IL-2 had indicated that plasma TGF beta activity increased in cancer patients following IL-2 therapy. We report a more detailed study of the quantitation of TGF beta activity in the plasma of 23 cancer patients treated with IL-2 immunotherapy. Of interest, we found that although elevation of the bioactive form of TGF beta occurred in most patients during IL-2 therapy, it was significantly higher in patients with clinical regression of tumor (p = .004). In the first 2 weeks of therapy increase of plasma TGF beta activity appeared to correlate with a decrease of platelet counts, suggesting that the factor may derive from the storage form of TGF beta contained therein.

Alterations of platelet function induced by interleukin-2.

We recently reported that thrombocytopenia and bleeding are often limiting effects of immunotherapy with interleukin-2 (IL-2). In order to understand the mechanisms that lead to this unexpected clinical toxicity, we studied the effects of IL-2 on in vitro platelet function. When platelet aggregation was studied using whole blood (impedance, electrical) aggregometry, inhibition of aggregation was detected within 1 min of the addition of exogenous IL-2 to whole blood. IL-2-induced platelet secretion was quantified by radioimmunoassay (RIA) of PF4, BTG, and TXB2 independent of the addition of an aggregating agonist (ADP). Platelet secretion and inhibition of aggregation were an indirect consequence of a cellular effect of IL-2 on mononuclear cells, since aggregation was normal when whole blood was depleted of mononuclear cells and its reconstitution with autologous mononuclear cells led to a cell concentration-dependent inhibitory effect of aggregation and release of alpha-granule components in the presence of IL-2. In order to understand the mechanism of platelet secretion mediated by IL-2-activated mononuclear cells, we quantified the release of eicosanoid products from cultures of mononuclear cells exposed to IL-2 and found a significant increase in TXB2. Our results indicate that platelet secretion, indirectly initiated by IL-2-activated cells, is followed by inhibition of aggregation. These findings may not only have important implications for the planning of clinical immunotherapy trials with IL-2, but may also provide a novel link for a better understanding of the relationships between the hemostatic and the immune systems.

Immunotherapy with IL2 by constant infusion and weekly doxorubicin.

Twelve women and 7 men, median age 58 (range 17-74), with a diagnosis of non-small-cell lung cancer (11 patients), inflammatory breast cancer (5 patients), osteosarcoma (2 patients), and colon carcinoma (1 patient) were studied. Treatment consisted of four consecutive 6-day courses of infusional interleukin-2 (IL2); 9 patients were treated with 20 X 10(6) IU/m2/day and 10 patients received weekly dose increments of 50% until the maximally tolerated dose was reached. One day after each course was completed patients received doxorubicin, 30 mg/m2; infusional IL2 was resumed 24 h after receiving doxorubicin. Rebounds of lymphocytes with high spontaneous synthetic rates of DNA occurred one day after stopping the infusion, despite doxorubicin administration. The kinetics were not different from earlier trials using IL2 alone. Sequential lymphocyte analysis showed that helper (CD4) and suppressor (CD8) T-cell subsets increased after the first week of treatment and declined thereafter, whereas the proliferation of natural killer (NK) cells (CD16) progressed through the 4-week treatment unaffected by doxorubicin. Mean cytolytic ability induced by IL2 against NK-resistant tumors in vitro was higher in patients who had evidence of clinical tumor regression and therefore is prognostically valuable (p = .02). Three patients left the study prematurely. Five partial remissions and 2 minimal responses were seen in the remaining 16 patients, but they were short-lived. Of the responding patients, only one had failed prior doxorubicin-containing chemotherapy. Toxicities attributable to IL2 and doxorubicin were encountered, and were manageable at these doses. Our data suggest that doxorubicin did not have cytotoxic or suppressive effects on lymphokine-induced lymphocyte functions and that both treatment modalities in combination are worthy of further investigation since they exert distinct and compatible cytotoxic mechanisms and induced tumor regressions with acceptable toxicity in a group of patients with poorly responsive cancers.

Phase III trial of brief intensive treatment of adult acute lymphocytic leukemia comparing daunorubicin and mitoxantrone: a CALGB Study.

This paper reports a study of the Cancer and Leukemia Group B (CALGB) comparing daunorubicin (DNR) or mitoxantrone (DHAD) in induction followed by multidrug intensification over 8 months in adult patients with acute lymphocytic leukemia (ALL). A total of 164 newly diagnosed patients were randomly assigned to either DNR or DHAD plus vincristine, prednisone and methotrexate given intravenously (i.v.) and interthecally (i.t.). Patients received four more intensification courses of chemotherapy and then all therapy was stopped. Central nervous system (CNS) prophylaxis consisted of nine infusions of intermediate dose methotrexate (MTX) and intrathecal MTX. DHAD and DNR were equally effective in producing complete remissions (63 and 65%, respectively). The estimated median remission duration is 10.2 and 12.3 months for the DHAD and DNR arms, respectively (p = 0.56). This study was stopped earlier than planned when it became apparent that remission duration for both arms was shorter than seen in our prior study in which all patients received more than 1 year of maintenance therapy. The estimated median survival is 18.3 and 20.6 months for the DHAD and DNR arms, respectively (p = 0.90). Younger patients and patients with a pre-treatment white blood count of less than 30,000/microliters had a significantly longer remission duration and survival. Eleven per cent of patients who achieved a complete remission have had a CNS relapse to date, which is not different from the rate in our prior study using cranial irradiation and i.t. MTX, implying that intermediate dose MTX with i.t. MTX may be as effective as cranial irradiation and i.t. MTX. This study suggests that some form of maintenance chemotherapy is required for the eradication of residual leukemia cells.

Chemotherapy of metastatic Merkel cell cancer.

Out of 16 cases of Merkel cell cancer identified in the records of the Mt. Sinai Medical Center or affiliates, 11 patients developed systemic metastases. Literature review confirms the substantial possibility of dissemination. Both in our series and in the literature, cytotoxic chemotherapy produced a high rate of usually short-lived response, although one of our patients with disseminated metastases achieved complete remission for two years.

Mitoxantrone and constant infusion etoposide for relapsed and refractory acute myelocytic leukemia.

In an effort to search for new, synergistic and non-cross-resistant antileukemic regimens, the Cancer and Leukemia Group B (CALGB) investigated the activity and toxicity of mitoxantrone in combination with etoposide for the reinduction of patients with relapsed or refractory acute myelocytic leukemia (AML). Mitoxantrone, 12 mg/m2 daily for 3 days, was combined with three dose levels of etoposide, 100, 150 and 200 mg/m2 daily by constant infusion for 5 days. There were 19 male and 13 female patients, with a median age of 46 (range, 21-74). Of these, nine were primarily refractory to daunorubicin and ara-C; 17 had one prior complete remission (CR), five had two prior CR, and one had three prior CR. Thirteen patients were entered at the first dose level, 11 were entered at the second, and eight at the third. All but one patient, whose death occurred within the first 2 days of treatment, are evaluable for toxicity. There were five CR (four at the first and one at the second dose level) and six partial remissions (PR) (three at the first dose level and three at the second). Unmaintained responses lasted 6-33 weeks. Median survival for all patients was 12.6 weeks. Anti-leukemic effects with severe marrow hypoplasia were observed in all patients; severe nausea and vomiting were seen in four. Severe mucositis, often indistinguishable from superimposed candidiasis, occurred in 40% of all patients; it was associated with dose-limiting esophagitis (three of seven evaluable patients) at the highest etoposide dose. Hepatic and renal dysfunction was severe in three patients; no treatment-related severe pulmonary or cardiac toxicity was observed. Posttreatment infectious complications were severe in 11 patients. In three cases, they were fatal--an incidence not dissimilar from that of other reinduction regimens in heavily pretreated patients. The regimen appears to be active; the combination of mitoxantrone, 12 mg/m2 daily for 3 days, with etoposide, 150 mg/m2/day for 5 days, by constant intravenous infusion is now being explored by the CALGB in a randomized phase II study against mitoxantrone plus diazoquinone and diazoquinone plus etoposide.

Sequential intermediate-dose cytosine arabinoside and mitoxantrone for patients with relapsed and refractory acute myelocytic leukemia.

Based on in vitro evidence of time-dependent synergistic kill of HL-60 leukemia cells exposed to Ara-C and mitoxantrone, 44 patients with relapsed or refractory AML and 3 with blastic CML were treated with a timed sequence of both drugs. There were 25 females and 22 males, with a median age of 53 (range 21-75). Of 31 patients with relapsed AML, 24 had one prior remission, 6 had two and 1 had three. Of these, 15 had failed a second reinduction attempt. Thirteen patients were primarily refractory to induction with Ara-C plus daunorubicin. Each dose of Ara-C, 500 mg/m2, was followed after 6 hr by mitoxantrone, 5 mg/m2, and the sequence was repeated four to six times (44-68 hr) in different cohorts of patients. All but two patients (one with blastic CML and one in relapse and refractory) are evaluable for response and toxicity. Of 16 patients in relapse without prior reinduction 7 achieved CR and 3 PR (62% response rate); there were 3 CR in the 14 patients who were in relapse and refractory (21% response rate) and 4 CR and 1 PR (35% response rate) in the 14 patients with primary anthracycline resistance. Five of seven patients previously exposed to mitoxantrone achieved CR. Response lasted from 2 to 42 months, with two patients alive and in continuing remission at 34 and 42 months. Average marrow recovery was seen after 25 days and time to remission was 30 days. Six patients died in induction (four from sepsis and two from the tumor lysis syndrome) and 21 had progressive disease. Chemotherapy was well tolerated with minor nausea and vomiting in 13 patients, moderate in 20, and severe in 2. Most patients did not have evidence of drug-induced mucositis: it was minor in 9 and moderate in 2. Renal dysfunction was attributable to the use of nephrotoxic antibiotics. Hepatic dysfunction was reversible and was minor in 10 patients, moderate in 13, and severe in 3. Sequential, timed administration of intermediate-dose Ara-C and mitoxantrone is an active and well-tolerated antileukemic regimen.

Thrombocytopenia during immunotherapy with interleukin-2 by constant infusion.

PURPOSE: To elucidate some of the possible mechanisms that lead to interleukin-2 (IL2)-induced thrombocytopenia. PATIENTS AND METHODS: We evaluated retrospectively the effects of immunotherapy with IL2 in 76 patients with disseminated cancer. The lymphokine was administered by constant infusion, daily for 6 days a week for 4 consecutive weeks. RESULTS: A significant decrease in platelet counts was seen after the first 6 days of therapy in all but two patients: 14 patients experienced grade 2 or 3 toxicity, 21 had grade 1 toxicity, and although the decrease in platelet counts could not be graded as toxicity in the remaining 41 patients, there was an average decrease of 32% from baseline platelet counts in 39 (p less than 0.0001). Thrombocytopenia appeared to be secondary to peripheral platelet destruction, since bone marrow biopsy specimens obtained during thrombocytopenia showed hyperplastic megakaryocytopoiesis. IL2 is inactivated by tubular resorption, and severity of thrombocytopenia was strongly correlated with IL2-induced renal dysfunction (p = 0.0004). Additionally, both renal dysfunction and thrombocytopenia were related to total dose of IL2 and were more pronounced in patients with worse baseline renal function and lower baseline platelet counts. The incidence of thrombocytopenia increased with subsequent IL2 therapy: life-threatening thrombocytopenia (less than 25,000/microL) was seen in nine of 57 patients, five of whom required transfusional platelet support. CONCLUSION: On the basis of preliminary observations, we hypothesize that thrombocytopenia induced by IL2 is caused by accelerated clearance of platelets by the reticuloendothelial system.

Mitoxantrone, vincristine, and dexamethasone in patients with refractory lymphoma.

Twenty-seven patients with failed malignant lymphomas (19 with intermediate grade, 4 with low-grade, 3 with high-grade lymphomas, and 1 with Hodgkin's disease) who had failed a median of 3 prior multidrug regimens, all previously exposed to anthracyclines (median prior doxorubicin 360 mg/m2), were treated with a combination of mitoxantrone (M), vincristine (V), and dexamethasone (D) every 4 weeks. Mitoxantrone was given in a 3 times daily schedule (days 1-3), at doses between 5 and 10 mg/m2/day; vincristine, 2-mg total dose, was given on day 1 and day 8; dexamethasone, 20 mg/m2, was given on days 1-5. A total of 71 courses was administered; there were 4 complete responses (CR) and 14 partial responses (PR) (response rate 66%). At the highest doses, hematological toxicity was severe (5 patients died while pancytopenic); the nadir for WBC and platelets was on day 13, with a median hematological recovery on day 23. There were transient hepatic, renal, and oral toxicities; vincristine-related neuropathy was seen in 8 patients. All patients had normal prestudy cardiac function, as assessed by gated pool scans; follow-up scans showed a greater than 15% decrease of the left ventricular ejection fraction (LVEF) in 2 patients, without evidence of cardiac dysfunction. Although responses lasted a median of 10 weeks (range 4-37), our data indicate that mitoxantrone, at the doses and schedules used, is an effective drug in malignant, doxorubicin-resistant lymphomas. This observation warrants the use of mitoxantrone in the upfront treatment of malignant lymphoma.

Systemic biodistribution of radioiodinated interleukin-2 in the rat.

Interleukin-2 (IL-2) is a lymphokine capable of modulating a variety of immune functions. In vitro and in vivo studies have shown promising cytotoxic potential. Despite numerous ongoing clinical trials, however, little is known about the biodistribution of this lymphokine after in vivo administration. In this study using a rat model, the fate of radioiodinated human recombinant IL-2 (RIL-2) was analyzed by camera imaging, autoradiography, and well counting experiments. Camera imaging demonstrated the liver and kidney to be the organs of greatest radioactivity accumulation with peak liver uptake noted at approximately 10 min from onset of infusion, and peak kidney uptake at approximately 20 min. Autoradiographic assessment of selected organs (kidney, adrenal, liver, lung, and brain) revealed marked heterogeneity of uptake in the kidney and adrenal gland with preponderance of RIL-2 in the cortex of these organs. A more homogeneous distribution of RIL-2 uptake was noted in liver, lung, and brain parenchyma. Well counting confirmed the liver and kidney as the organs of greatest RIL-2 accumulation. Knowledge of the biodistribution of IL-2 may be of benefit both in studying mechanisms of toxicity and in designing novel therapeutic approaches.

Recombinant interleukin-2 by continuous infusion and adoptive transfer of recombinant interleukin-2-activated cells in patients with advanced cancer.

Twenty-five patients with disseminated cancer (nine with renal cell carcinoma, five with melanoma, three with Hodgkin's lymphoma and chronic myelocytic leukemia [CML], two with soft tissue sarcoma, one each with large-cell lymphoma, breast cancer, and colon cancer), 13 males and 12 females, aged 25 to 68, were treated with recombinant human interleukin-2 (rIL2) by continuous infusion and adoptive transfer of autologous lymphocytes activated in vitro with IL2. Patients underwent leukapheresis on days 1, 8, 15, and 22 of the treatment. Cells, bulk activated for 20 hours in serum-free culture medium with 1,000 U IL2/mL in transfusion transfer packs as culture vessels, were transfused the following day. The infusion of IL2 by continuous infusion for six days started immediately after each adoptive transfer for 4 weekly courses. The dose of IL2 was escalated weekly in each patient; starting doses of IL2 were also escalated in subsequent cohorts of patients until maximally tolerated doses were reached. Nine patients had objective tumor regressions (three with renal cell cancer, two with Hodgkin's lymphoma, and one each with melanoma, sarcoma, breast, and colon cancer). Six responses were partial, two were minor, and one was mixed. Responding patients were maintained with IL2 by continuous infusion for six days every 6 to 8 weeks, without adoptive cell transfer. The median duration of responses was 16 weeks (3 to 60 + weeks). Tumor regression was related to the dose of IL2 (greater than or equal to 3.4 x 10(6) U/m2/d for six days) and to the in vivo lymphoproliferative effects of the lymphokine, but not to the total number of cells adoptively transferred. Side effects of treatment were transient and quickly reversible. Renal, hepatic dysfunction, and dyspnea were directly related to the dose of IL2 and to lymphocytosis. Other toxicities were mild hypotension with mild fluid retention, oral mucositis, anemia, thrombocytopenia, fever, and fatigue.