A Phase I Study of Recombinant Interleukin 2 in Melanoma Patients. Toxicity and Clinical Effects

A Phase II Study of the Administration of Recombinant Interleukin 2 (rIL-2) Plus Lymphokine Activated Killer (LAK) Cells in Stage IV Melanoma Patients

From January 1987 to February 1988, 15 stage IV melanoma patients were treated with two courses of bolus injection of rIL-2 plus LAK cell infusions at the National Cancer Institute of Milan. The original treatment regimen included a first course of rIL-2 administration (400 μg/m5 bolus injection 3 times a day [TID] for 4 days) and a second course of rIL-2 administration (800 μg/m2 bolus injection TID for 7 days) separated by 4 consecutive daily leukaphereses. Autologous lymphokine activated killer (LAK) cells were reinfused into each patient on three occasions during the second period of rIL-2 administration. Due to the appearance of grade III–IV neurological, hepatic and cardiopulmonary toxicity, 7 patients discontinued dosing before the end of treatment, one patient desired to be withdrawn and one patient died from rapidly progressive disease, although complications of rIL-2 administration may have contributed to her death. Only 6 patients completed the schedule without evidence of major intolerance, even though the planned dose during the second course of rIL-2 was reduced to 400 μg/m2. The complete duration of treatment ranged from 11 to 19 days. The total dose of rIL-2 injected ranged from 12.6 to 30.4 mg. The number of infused LAK cells ranged from 15.5x109 to 60x109/patient. Two of the 14 evaluable patients showed a minor anti-tumor response. In 5 patients new metastases in other sites were documented from 2 to 5 months after completion of dosing. No apparent association was found between progression of the disease (or the appearance of new metastases) and the total dose of rIL-2 injected, the number of LAK cells administered or the number of days of treatment. By December 1988, all patients had died of their disease in a period ranging from 3 to 14 months from the last injection of rIL-2. The lack of significant clinical responses in this study and the high toxicity of this treatment lead us to conclude that at least as far as melanoma patients are concerned, adoptive immunotherapy with rIL-2 plus LAK cells (as described here) is not a justifiable treatment option unless new evidence presents itself.

Antitumor activity of interleukin-21 prepared by novel refolding procedure from inclusion bodies expressed in Escherichia coli

Interleukin-21 (IL-21) has recently been identified as a novel 4-helix-bundle type I cytokine possessing a cytokine receptor gamma chain essential for the immune response. We report the preparation and functional characterization of Escherichia coli-expressed recombinant human IL-21 (rIL-21). The rIL-21, expressed as insoluble inclusion bodies in E. coli, was solubilized and then refolded by using a modified dialysis method. The introduction of redox reagents during refolding led to a dramatic increase in the refolding efficiency. Circular dichroism spectrum analysis showed that the refolded rIL-21 had an alpha-helix as a secondary structure, which is a characteristic of type I cytokines. Flow cytometry confirmed previous reports that rIL-21 binds to CD3-activated T cells (T-LAK) and to cell lines Raji, HL60, and Jurkat. rIL-21 stimulated the proliferation of T-LAK but not peripheral blood mononuclear cells, and this effect seems to be identical to that of co-stimulation with anti-CD3 antibody. Growth inhibition assay indicated that enhancement of the cytotoxicity of T-LAK to the human bile duct carcinoma TFK-1 depended on the concentration of rIL-21. Thus, refolded rIL-21 had activity identical to that of authentic IL-21 and enhanced the anti-tumor activity of T-LAK. These conclusions suggest the potential use of the refolded cytokine in adoptive immunotherapy using T-LAK cells and in the discovery of other functions of the cytokine.

Pharmacokinetics of repeated i.v. bolus administration of high doses of r-met-Hu interleukin-2 in advanced cancer patients

We studied the pharmacokinetics of recombinant methionyl human interleukin-2 alanine (r-met-Hu IL-2 [ala 125]) given at high doses by i.v. bolus according to Rosenberg's initial schedule in seven patients with advanced cancer. Serum concentrations of IL-2 were measured by radio-immunoassay. The drug followed second-order kinetics. During the administration of repeated high doses of IL-2, we noted a progressive increase in the volume of distribution (from 5,984 +/- 1,850 to 9,084 +/- 4,345 ml) and a progressive decrease in the AUC (from 32,643 +/- 3,817 to 22,397 +/- 511 IU min ml-1) and beta-half-life (from 61 +/- 14 to 48 +/- 6 min); the peak serum IL-2 concentrations also decreased significantly. We attribute these findings to an expansion of the extracellular fluid space and an increase in the number of IL-2 target cells during the treatment.

Pathologic findings associated with interleukin-2-based immunotherapy for cancer: a postmortem study of 19 patients

The use of interleukin-2 (IL-2), either alone or in combination with lymphokine-activated killer cells, tumor infiltrating lymphocytes, or other immunotherapeutic agents has added a new list of alternatives to conventional antineoplastic regimens. Little information is available about the pathologic changes occurring in patients treated with these agents. In this study, we reviewed the necropsy materials from 19 patients, 12 men and 7 women, with a variety of malignancies including melanoma, renal cell carcinoma, gastrointestinal and pulmonary adenocarcinoma, and metastatic gastrinoma, who died after receiving IL-2-based immunotherapy. Death occurred at intervals ranging from less than 1 hour to 143 days following the last dose of therapy. All patients dying at or less than 43 days following cessation of therapy had lymphoid infiltrates of varying intensity in residual tumor. At necropsy, the major cause of death unrelated to the presence of metastatic tumor was bacterial sepsis. In addition, we found evidence of significant cardiac and pulmonary toxicity: two patients with acute myocardial infarction, one with and one without significant coronary artery disease, two cases of unexplained lymphocytic myocarditis, and one case of fatal pulmonary capillary plugging following an infusion of lymphokine-activated killer cells. Thus, not unlike other forms of therapy for cancer, IL-2-based immunotherapy does not appear to be without significant toxicity.

In vivo activation of lymphocytes in melanoma patients receiving escalating doses of recombinant interleukin 2

A phase-I study of the recombinant, non-mutagenized interleukin 2 (rIL2, BioleukinTM) was performed in 12 melanoma patients (Pts). From 100 to 800 micrograms/m2 of rIL2 were administered by i.v. bolus injection, TID for 4-8 days. Side-effects included fever, malaise, low serum K+ and Ca++ values, electrocardiographic abnormalities, leukopenia and thrombocytopenia. No major organ toxicity and no significant fluid retention were observed at the administered doses. Treatment induced a rapid depletion of peripheral blood lymphocytes (PBL) with a rebound (2-6 times the pre-treatment values), 24-48 hr after rIL2 discontinuation. PBL obtained between the 5th treatment day and the 2nd post-treatment day showed: (a) enhanced proliferation (II/12 Pts) with stimulation indexes of 6-52; (b) increased cytotoxicity against autologous tumor cells (2/2 Pts), allogeneic melanomas (5/7 Pts), the Daudi (5/6 Pts) and K562 cell lines (7/12 Pts); and (c) increased expression of IL2 receptors (8/12 Pts) and of DR antigens (6/12 Pts). Lymphocytes collected 1-2 days after treatment and activated in vitro with rIL2 showed a more rapid development of tumor cytotoxicity, with an earlier loss of activity. Spontaneous proliferation, autologous or allogeneic tumor cytotoxicity and expression of IL2 receptors obtained after in vivo treatment with rIL2 were significantly weaker than those induced during in vitro stimulation. No major objective responses were detected in these patients.