Successful treatment of disseminated human Hodgkin's disease in SCID mice with deglycosylated ricin A-chain immunotoxins

To evaluate the effects of deglycosylated ricin A-chain (dgA) immunotoxins against disseminated Hodgkin's lymphoma, we used RFT5.dgA (CD25) and IRac.dgA (70 kD) to treat L540Cy Hodgkin cells in severely immunodeficient SCID mice. In this model, more than 90% of the animals developed multiple lymphomas in various organs such as the lymph nodes, liver, bone marrow, and extranodal sites that killed untreated animals after a mean survival time (MST) of 36.3 days. A single intraperitoneal injection of 8 micrograms of either immunotoxin rendered 95% (RFT5.dgA) and 93% (IRac.dgA), respectively, of mice tumor-free when applied 1 day after tumor challenge. The MST of the RFT5.dgA-treated group was extended by more than 80 days (P < .00001). SCID mice treated 12 days after tumor challenge had lower remission rates (46%), suggesting that the antitumor effect of the immunotoxins depends on the number of tumor cells present. We conclude that ricin A-chain immunotoxins have potent antitumor effects against disseminated Hodgkin's tumors in SCID mice and that this model is ideally suited for the evaluation of different immunotoxin treatment modalities.

Disseminated growth of Hodgkin's-derived cell lines L540 and L540cy in immune-deficient SCID mice

Local tumor growth has been reported after subcutaneous and intraperitoneal injection of Hodgkin's disease (HD) derived cell lines into different immunodeficient mouse strains. An animal model with disseminated growth of tumor cells would be useful for studying the in vivo biology of HD cells as well as for preclinical testing of new therapeutic regimens. For this purpose the HD-derived cell lines L540, L540cy, L428, and KM-H2 were injected intravenously into SCID mice. In contrast to L428 and KM-H2, widespread neoplasia occurred after a period of four to six weeks following injection of L540 and the subline L540cy. Lymph nodes were found to be the preferred site of tumor growth. CD30 surface antigen expression on Hodgkin cells and the karyotype of the tumor cells were preserved in the animal host. Thus, to a large extent, the SCID mouse model mimics the dissemination pattern of Hodgkin's disease in man. To evaluate the role of adhesion molecule expression in the dissemination of HD-derived cell lines, CD44 and members of the immunoglobulin, integrin, selectin, and Fc receptor families were quantified by flow cytometry. CD30 expression was also measured. Although CD44 expression has been correlated with dissemination in non-Hodgkin's lymphoma (NHL), this was not the case in the Hodgkin's SCID mouse model. CD44 was not expressed on the disseminating cell lines L540 and L540cy but was expressed in the nondisseminating lines L428 and KM-H2.

Cytokine efficiency in the treatment of high-grade malignant non-Hodgkin's lymphomas: results of a randomized double-blind placebo-controlled study with intensified COP-BLAM +/- rhGM-CSF

In high-grade malignant non-Hodgkin's lymphomas (hNHL) recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) was evaluated as support to chemotherapy. In a phase III trial, 172 patients (age 18-73 years, stage II-IV) were risk-stratified according to LDH levels and lymphoma size and randomized to receive rhGM-CSF (400 micrograms) (87 patients) or placebo (85 patients) subcutaneously days 8-14 of each cycle of an intensified COP-BLAM regimen. RhGM-CSF significantly reduced the length and nadir of neutropenia, the length of fever episodes, the frequency of all and of severe infections, and of hospitalization and antibiotic requirements. Complete response rates were 63% for all patients and 64% vs. 61% (n.s.) in the rhGM-CSF vs. the control group. Deviations from protocol in applied dosages of myelotoxic drugs and in cycle intervals maintained differed slightly in favor of the rhGM-CSF arm. However, there were no significant differences in overall survival between the GM-CSF treatment and control groups (21 vs. 23 months). Early relapse rates were markedly lower than in the standard-dose COP-BLAM/IMVP-16 regimen. Thus, GM-CSF abates toxic side effects of chemotherapy and may help to maintain dose intensity in high-risk hNHL.

Immunotoxins: is there a clinical value?

Drug targeting is an attractive new approach to killing malignant cells, thereby leaving normal tissue unharmed. A decisive breakthrough was the advent of hybridoma technology, making monoclonal antibodies (MoAb) available in limitless supply. To construct reagents with selectivity for certain tumor cells, MoAbs or Fab' fragments were chemically linked to ribosome-damaging toxins derived from plants or bacteria like ricin, abrin, saporin, Pseudomonas exotoxin (PE), and diphtheria toxin (DT) to form immunotoxins, which combined the selectivity of the carrier moiety with the potency of the toxin moiety. The first generation of these immunotoxins showed impressive results in vitro but in most cases disappointing antitumour effects in animals or humans. By contrast, the second generation of immunotoxins, consisting of either A chain immunotoxins with a greatly improved stability in vivo or so-called 'blocked' ricin immunotoxins, have been demonstrated to be extremely effective in several animal models. Preliminary results of the current clinical trials suggest a possible clinical use of immunotoxins in leukemia and lymphoma patients. Genetically engineered fusion toxins have become available, which consist of a growth factor or a cytokine fused to a toxin moiety. In this paper, we will review the features of the three groups of immunotoxins which are most frequently used, i.e., ricin A chain and similar immunotoxins, blocked ricin immunotoxins, and recombinant toxins constructed with Pseudomonas exotoxin or diphtheria toxin.

Fludarabine single-agent therapy for relapsed low-grade non-Hodgkin's lymphomas: a phase II study of the German Low-Grade Non-Hodgkin's Lymphoma Study Group

In a phase II study, 45 patients with advanced low-grade non-Hodgkin's lymphomas (NHLs) who had failed on or had relapsed after first-line chemotherapy were treated with a 5-day regimen of fludarabine, 25 mg/m2/d, by a 30-minute infusion. All patients were pretreated and had received one to 11 preceding regimens (median, three regimens). Histologic subtypes included 17 centrocytic/centroblastic NHLs, three centrocytic NHLs, 23 lymphoplasmocytoid immunocytomas, and one case each of peripheral T-cell and lymphocytic lymphoma. From 38 presently evaluable patients, 12 (31%) cases responded (five [13%] complete and seven [18%] partial remissions). Treatment-associated toxicity was mild to moderate, with myelosuppression comprising the major side effect. From the 12 complete and partial response patients, seven are currently in unmaintained remission for more than 12 months. These data indicate a high activity of fludarabine in heavily pretreated patients with low-grade NHL. Further investigations are warranted to assess the most appropriate usage for this highly promising agent at earlier stages of low-grade NHL therapy.

Lysis of malignant B cells from patients with B-chronic lymphocytic leukemia by autologous T cells activated with CD3 x CD19 bispecific antibodies in combination with bivalent CD28 antibodies

Bispecific antibodies (bi-MABs) can be used to target T cells to autologous tumor cells. It has been shown that the activation of resting human T cells requires two independent signals, namely the cross-linking of the T-cell receptor (TCR)-CD3 complex together with the CD28 homodimer. In the present study, we demonstrate the activation of T cells from patients with chronic lymphocytic leukemia (CLL) using bi-MABs against the CD3 and CD19 antigens (CD3 x CD19) in combination with monospecific, bivalent antibodies against the CD28 antigen. Mononuclear cells from patients with CLL were cultured with the bi-MAB CD3 x CD19 and monospecific CD28 antibodies. The CD3 x CD19 bi-MABs were isolated by the hybridoma-hybridoma fusion technique and purified by hydrophobic interaction chromatography. T-Cell activation as demonstrated by increased proliferation, upregulation of T-cell activation markers (CD25, CD38), and cytotoxicity against autologous CLL cells and allogeneic B cells was shown in seven of eight CLL specimens. The stimulation with CD3 x CD19 bi-MABs with CD28 antibodies preferentially induced proliferation of CD4+ T cells. The effective dose of purified antibodies required for optimal T-cell activation was 100 ng/mL in vitro, which suggests that this antibody combination may be useful for immunotherapy of patients with B-CLL.

Growth of Hodgkin cell lines in severely combined immunodeficient mice

No animal model exists for the in vivo growth of Hodgkin's-lymphoma-derived cells. Neither unmanipulated Hodgkin's-disease(HD)-derived cell lines nor primary biopsy tissue could be grown in nude mice. Since the severe combined immunodeficient (SCID) mouse has been reported to be a better recipient for transplanted human lymphatic tissue than the nude mouse, we tested whether SCID mice provide suitable conditions for the in vivo growth of HD cell lines. Tumorigenicity of HD cells was tested in untreated and pre-treated SCID mice and in another combined immunodeficient mouse strain, beige/nude/X-linked immunodeficient (BNX) mouse. SCID mice supported in vivo growth of the 6 HD cell lines tested (L428, L540, L591, DEV, HD-LM2, KM-H2). Only one of the 6 lines (DEV) was tumorigenic in BNX mice. No HD cell line proliferated in T-cell-deficient nude mice. Thus, in vivo growth of HD cell lines appeared to be related to the degree of host immunodeficiency. Additional growth supportive treatments such as fibrosarcoma co-transplantation, intraperitoneal mineral oil injection or immunosuppressive pre-treatment (anti-asialo-GMI-antibody injection) permitted growth of 3 additional HD cell lines in BNX mice. The immunophenotype and karyotype of explanted graft cells were identical to the original cell lines. Our experiments describe an effective and reproducible xenograft model for growth of Hodgkin's-disease-derived cell lines. This may be of value for elucidating the growth characteristics of Hodgkin's-lymphoma-derived cells as well as for testing new therapeutic regimens.

[New perspectives in oncology: is selective destruction of tumor cells with immunotoxins in Hodgkin's disease an additional therapeutic alternative?]

In the present paper, the authors describe the production and testing of immunotoxins for clinical application in Hodgkin's disease. The immunotoxins were constructed by chemical coupling of deglycolysated ricin-A to monoclonal antibodies against antigens on Hodgkin's and Reed-Sternberg cells (CD25, CD30, IRac). The cytotoxic effect of the immunotoxins was investigated in vitro against Hodgkin's and Reed-Sternberg cells (H-RS) and in vivo against solid Hodgkin's tumors in nude mice and disseminated Hodgkin's tumors in SCID mice. Cross-reactivity with normal tissue and the staining behaviour observed in sections of Hodgkin's tissue of various subtypes proved important parameters for the assessment of clinical applicability. Of more than 30 evaluated MoAb's, eight immunotoxins were produced, of which six showed both, cytotoxic effects of considerable potency against Hodgkin's tumor cells and low cross-reactivity with vital human organs. The most effective immunotoxin, RFT5 gamma 1.dgA, (CD25) inhibits the growth of H-RS cells at concentrations of 7 pMol and destroys about 60% of solid Hodgkin's tumors of 0.5 cm in diameter in nude mice. This immunotoxin binds to virtually all tumor cells in more than 90% of patients with Hodgkin's disease. Sufficient quantities of RFT5 gamma 1.dgA were produced for the treatment of patients with refractory Hodgkin's disease. These patients are currently being treated in a phase I clinical trial.

Preliminary report: growth of Hodgkin's lymphoma derived cells in immune compromised mice

Until now there has been no satisfactory animal host for the in vivo growth of Hodgkin lymphoma cells. With the exception of one mutant subline (L540Cy) none of the other Hodgkin derived cell lines nor Hodgkin's disease (HD) derived lymphatic tissue could be propagated in suitable animal systems such as the T-cell deficient nude mouse. Recently, the severe combined immunodeficient (SCID-) mouse has been demonstrated as a possible recipient for human lymphatic tissue. In the present study, we have evaluated the SCID mouse as a possible in vivo model for Hodgkin's lymphoma. I) We demonstrate that seven permanent cell lines derived from patients with Hodgkin's disease grow progressively in SCID mice after subcutaneous and intraperitoneal inoculation. II) In addition, after intravenous injection, two of these lines (L540, L540Cy) show a disseminated growth pattern resembling the distribution of HD cells in man (involvement of lymph nodes, liver and bone marrow but not of spleen). The observed reproducible disseminated tumor growth establishes the SCID mouse as a new animal model for experimental treatment strategies in Hodgkin's lymphoma. III) We present preliminary results of the transplantation of primary material from 13 patients with Hodgkin's disease. Material from two patients induced human tumors in the SCID mice recipients, whereas material from two others led to the induction of mouse lymphomas. The human tumors showed three distinct histological patterns: 1) Lymphoproliferative disease (LPD); 2) anaplastic large cell lymphomas (ALCL); 3) Hodgkin like lesions (HLL). In vitro cell lines established from human SCID mouse tumors were of B-lymphoid origin, were EBV-positive and showed numerical and some structural chromosomal aberrations of varying degree.

Experimental therapy in Hodgkin's disease

Hodgkin/Reed-Sternberg (H-RS) cells express lymphoid activation markers like CD25 and CD30 which are present only on a small minority of normal cells. Currently, most experimental approaches in Hodgkin's lymphoma are aimed at targeting H-RS cells via monoclonal antibodies against CD25 and CD30: immunotoxins constructed by linking the antibody moiety chemically to deglycosylated ricin A-chain destroy up to 60% of small H-RS tumors in mice. The most potent immunotoxin is currently being scaled up for clinical trials. Other experimental strategies use bispecific constructs that, after binding to the cell surface of H-RS cells, convert prodrugs into their toxic counterparts, or employ monoclonal antibodies for active immunotherapy.

Immunotoxins constructed with anti-CD25 monoclonal antibodies and deglycosylated ricin A-chain have potent anti-tumour effects against human Hodgkin cells in vitro and solid Hodgkin tumours in mice

Twenty-three monoclonal antibodies (MAbs) against the IL-2 receptor alpha-chain (CD25) were evaluated as ricin A-chain immunotoxins for the treatment of Hodgkin's disease. Primary screening used an indirect assay in which the cells were treated with the test antibody followed by a Fab' immunotoxin against mouse immunoglobulin. This screening identified 5 MAbs which inhibited protein synthesis in L540 Hodgkin cells by 50% at a concentration (IC50) of 6 x 10(-11) M or less: RFT5 gamma 1, RFT5 gamma 2a, B-B10, B-F2 and B-G3. These MAbs were then linked directly to deglycosylated ricin A-chain (dgA) and were confirmed to have potent and specific toxicity for L540 cells. The immunotoxins had the following potency order: RFT5 gamma 1 greater than RFT5 gamma 2a greater than B-B10 greater than B-F2 greater than B-G3. The most effective immunotoxin, RFT5 gamma 1.dgA, had an IC50 value of 7 x 10(-12) M, which is the same as that of whole ricin. In vivo, a single intravenous injection of 48 micrograms of RFT5 gamma 1.dgA, RFT5 gamma 2a.dgA, B-B10.dgA or B-F2 induced lasting complete remissions in 78, 66, 50 and 44%, respectively, of nude mice bearing subcutaneous solid L540 tumours of 0.7 cm diameter. Two tumours which regrew after B-B10.dgA treatment were re-established in tissue culture. Both had reduced sensitivity to B-B10.dgA in vitro but not to immunotoxins recognizing different antigens on Hodgkin cells. The MAbs that produced the most potent immunotoxins, RFT5 gamma 1, RFT5 gamma 2a and B-B10, had no significant cross-reactivity with normal human tissues outside the lymphoid system as judged from indirect immunoperoxidase staining of frozen sections. By contrast, B-F2 strongly stained normal human renal tubules.

Resistance of myeloid leukaemia cell lines to ricin A-chain immunotoxins

Nineteen monoclonal antibodies that recognize antigens on myeloid leukaemia cells were screened upon HL60, KG1, U937 and K562 cells for their ability to form effective ricin A-chain immunotoxins. The screening was performed using an indirect assay in which the cells were treated firstly with the test antibody and then with a Fab' immunotoxin directed against mouse immunoglobulin. Only two antibodies, MEM75 and 120-2A3, both directed against the transferrin receptor (TfR) were predicted to form immunotoxins that would inhibit protein synthesis by the cells by 50% at a concentration (IC50) of 10(-8) M or less. This prediction was subsequently confirmed using several of the antibodies directly conjugated to ricin A-chain. By contrast, the same immunotoxins were highly toxic to non-myeloid cells which shared the target antigens. A comparison was made between the rates of endocytosis and degradation by HL60 cells of an anti-TfR immunotoxin 120-2A3.dgA, that was effective at killing myeloid cells, and a CD33 immunotoxin, p67-7.dgA, that bound to myeloid cells but did not kill them. The difference in potency of the two immunotoxins on HL60 cells was not due to deficient uptake of p67-7.dgA but was probably due to the more rapid intracellular degradation of p67-7.dgA. Fast and effective degradation in lysosomes, if a general finding, could explain the poor susceptibility of myeloid cells to ricin A-chain immunotoxins.

Specific activation of the prodrug mitomycin phosphate by a bispecific anti-CD30/anti-alkaline phosphatase monoclonal antibody

The bispecific monoclonal antibody (Bi-MAb) HRS-3/AP-1 was developed by somatic hybridization of the 2 mouse hybridoma cell lines HRS-3 and AP-1, which produce monoclonal antibodies with reactivity against the Hodgkin's- and Reed-Sternberg cell-associated CD30 antigen and alkaline phosphatase, respectively. After an active incubation with alkaline phosphatase, respectively. After an active incubation with alkaline phosphatase, purified whole immunoglobulin molecules and F(ab')2 fragments of the Bi-MAb were equally effective in converting a relatively noncytotoxic prodrug, mitomycin phosphate (MOP), into mitomycin alcohol, which was 100 times more toxic to the Hodgkin's- and Reed-Sternberg cell line L540 (CD30+) than MOP. The cytotoxic activity of MOP was unaffected when the cells were pretreated with either the Bi-MAb or the enzyme alone. The Bi-MAb HRS-3/AP-1 did not bind to HPB-ALL cells (CD30-) and was not able to activate MOP on these cells. In cocultivation experiments with HPB-ALL and L540 cells, the activation of MOP by the Bi-MAb HRS-3/AP-1 and alkaline phosphatase led to considerable cytotoxicity against the antigen-negative bystander cells. Thus, this immunotherapeutic approach might be effective in tumors in which not all the tumor cells express the respective tumor antigen.

Antitumor effects of ricin A chain immunotoxins prepared from intact antibodies and Fab' fragments on solid human Hodgkin's disease tumors in mice

Three monoclonal antibodies which strongly bind to Hodgkin and Reed-Sternberg cells and two corresponding Fab' fragments were linked to deglycosylated ricin A chain (dg A) to evaluate their potential as immunotoxins for the treatment of Hodgkin's disease. Two of the antibodies, Ber-H2 and HRS-3, were shown to bind to the same epitope on the CD30 antigen, whereas the third antibody, IRac, bound to a different antigen. None of the antibodies significantly cross-reacted with normal human tissues as judged by indirect immunofluorescence and immunoperoxidase analyses on frozen sections from 28 normal tissues. All three antibodies formed potent and specific immunotoxins. They inhibited protein synthesis of the L540 Hodgkin's disease cell line in vitro by 50% at concentrations of 1 x 10(-11) M for IRac.dgA, 9 x 10(-11) M for HRS-3.dgA, and 2 x 10(-10) M for Ber-H2.dgA. HRS-3 Fab' and IRac Fab' immunotoxins were 7.8- and 60-fold less cytotoxic, respectively, than their intact counterparts in vitro. In vivo, a single i.v. injection of a dose of Ber-H2.dgA, HRS-3.dgA, or IRac.dgA corresponding to 40% of the LD50 induced lasting complete remissions in 38, 44, and 50%, respectively, of mice with solid s.c. L540 tumors of 60 to 80 mm3 size (0.5-cm diameter). At equivalent dosage (40% of the LD50), the HRS-3 Fab'.dgA and the IRac Fab'.dgA both induced lasting complete remissions in 25% of the mice, although the HRS-3 Fab'.dgA was significantly superior to IRac Fab'.dgA at retarding tumor growth in the remaining animals. The effectiveness of the immunotoxins depended on the size of the tumor at the time of injection, since IRac.dgA treatment induced complete remissions in 100% of mice with small tumors (10 to 20 mm3, approximately 0.3 cm in diameter) but only 13% of mice with larger tumors of 400 to 600 mm3 (approximately 1 cm in diameter). Tumors which regrew after IRac.dgA treatment mainly consisted of antigen-deficient mutants having reduced sensitivity to IRac.dgA but normal sensitivity to HRS-3.dgA. It is concluded that HRS-3.dgA, HRS-3 Fab'.dgA, and IRac.dgA are candidates for the treatment of Hodgkin's disease in humans.

Evaluation of ricin A chain-containing immunotoxins directed against the CD30 antigen as potential reagents for the treatment of Hodgkin's disease

Five monoclonal CD30 antibodies and two Fab' fragments were linked to deglycosylated ricin A chain (dgA), and their potential as immunotoxins for the treatment of Hodgkin's disease was evaluated. Cross-blocking experiments demonstrated that HRS-1, HRS-3, HRS-4, and Ber-H2 recognize the same epitope on the CD30 antigen and that Ki-1 binds to a different epitope. Scatchard analyses showed that HRS-3, HRS-4, and Ber-H2 bound strongly to L540 Hodgkin cells (Kd 15, 7, and 14 nM, respectively), whereas HRS-1 and Ki-1 bound more weakly (Kd 160 and 380 nM, respectively). The different affinities of the antibodies correlated closely with their cytotoxic potency as immunotoxins. HRS-3.dgA, HRS-4.dgA, and Ber-H2.dgA inhibited the protein synthesis of L540 cells by 50% at concentrations of 0.9-2.0 x 10(-10) M, whereas HRS-1.dgA and Ki-1.dgA were about 100 times less potent with 50% inhibitory concentrations of 0.8-1.0 x 10(-8) M. The most effective immunotoxins, HRS-3.dgA and HRS-4.dgA, were only 15 times less toxic than ricin itself. HRS-3 Fab'.dgA and HRS-4 Fab'.dgA were 7.8 and 3 times less potent than their IgG.dgA counterparts with 50% inhibitory concentrations of 7 x 10(-10) and 3 x 10(-10) M, respectively. Staining of human tissues revealed an unexpected cross-reactivity of HRS-4 with pancreatic cells of malignant and nonmalignant origin. HRS-1, HRS-3, Ber-H2, and Ki-1 showed very little cross-reactivity with any normal human tissues. It is concluded that HRS-3.dgA and HRS-3 Fab'.dgA are the immunotoxins of choice for in vivo therapy.

Phase I trial of recombinant interleukin-2 and cyclophosphamide: augmentation of cellular immunity and T-cell mitogenic response with long-term administration of rIL-2

Long-term subcutaneous (s.c.) administration of recombinant Interleukin-2 (rIL-2) was evaluated in 18 patients with advanced malignancy who received escalating doses of rIL-2 (1.0-9.8 X 10(6) U/m2) s.c. five times per week for a median of 38 days (range 5-228 days). Prior to the s.c. phase of the study, 24 patients received low doses (50 or 350 mg/m2) of cyclophosphamide (CPM) i.v. on day 1 followed by 10 doses (days 5-9 and 12-16) of rIL-2 (1 X 10(6) U/m2) given by 6 h i.v. infusion. There were no major antitumor effects. Toxicity was not clearly dose-related, with pain and induration at s.c. injection sites, fatigue, malaise, and palpitations most often observed. Pretreatment baseline ranges (PBR), which are 95% prediction intervals that reflect both intra- and interpatient variability, were calculated for nine hematologic and immunologic variables derived from 21 of the 24 patients. While pretreatment with CPM had no significant effect on these variables during the i.v. phase of the study as compared to a prior study using an identical rIL-2 i.v. infusion schedule, prolonged administration of s.c. rIL-2 was associated with (a) enhancement of natural killer (NK) cytotoxicity against K562 in 13 of 21 patients (p less than 0.00001), (b) increases in cytotoxicity against K562 (15 patients) and against Daudi (9 patients) in the presence of 10 U/ml of rIL-2 (p = 0.007), (c) increases in the proliferative response in vitro to OKT3 and rIL-2 in 12 patients (p less than 0.00001), (d) lymphocytosis with increase in percentage of Tac (13 patients, p less than 0.00001), T8 (11 patients, p = 0.0005), and T9 (8 patients, p = 0.021) expression, and (e) eosinophilia. While initial rises in some of these variables occurred during the i.v. phase of the study, maximum increases for all variables except T9 positivity occurred during prolonged s.c. therapy. Nine of 10 patients studied while on therapy greater than 50 days had anti-rIL-2 antibodies in an enzyme-linked immunosorbent assay; in only one case was the antibody neutralizing. This study demonstrates that significant enhancement of cytotoxicity against both NK-sensitive and -resistant targets and improvements in T-cell mitogenic response occur with long-term administration of rIL-2. Further evaluation of long-term administration of tolerable doses of rIL-2 is warranted.

A phase I trial of intraperitoneal recombinant interleukin 2 in patients with ovarian carcinoma

Seven patients with refractory stage III ovarian carcinoma were treated with escalating doses of human recombinant interleukin 2 (rIL-2) administered via the intraperitoneal (IP) route in an attempt to establish a dose and schedule of rIL-2 suitable for prolonged outpatient IP administration. Three patients went on to receive outpatient maintenance treatment twice weekly for 2-3 months. Doses ranged from 10(5) to 5 x 10(7) U/m2. The dose found most suitable for twice weekly outpatient IP administration was 10(6) U/m2. Dose-limiting toxicities consisted of diarrhea resulting in hypovolemia (5 patients) fever and chills (4 patients), nausea and vomiting (1 patient), mental status changes (2 patients), and azotemia (1 patient). These side effects were not prevented by indomethacin. Significant hypotension was not observed. Pharmacokinetic studies revealed extremely high IP concentrations of IL-2 which persisted for more than 24 hours. After a dose of 10(6) U/m2, the IP concentrations ranged from 670 to 760 U/ml. In one patient in whom concurrent serum concentrations were determined, the IP concentrations were over 100-fold higher than serum levels. After a dose of 10(7) U/m2, the IP concentrations of IL-2 ranged from 8700 to 14000. Concurrent serum levels in one patient revealed IP concentrations over 500-fold higher than serum levels. There were no consistent changes in T cell surface and activation markers on mononuclear cells from peripheral blood in 3 patients tested. Natural killer cell (NK) activity in peripheral blood increased in the three patients in whom it was measured. Four of the 7 patients progressed on treatment; 3 patients remained stable. We conclude that 10(6) U/m2 of rIL-2 is well-tolerated when administered by the IP route and that concentrations of IL-2 well in excess of that required to enhance cell-mediated cytotoxicity in vitro persist in the IP fluid for at least 24 hours.

Expansion of activated T-lymphocytes in patients treated with recombinant interleukin 2

Recombinant interleukin 2 (rIL 2, Cetus) was administered in escalating doses to 30 patients with advanced malignancy, including 14 patients with the epidemic form of Kaposi's sarcoma, in 2 week treatment cycles as a 6 h i.v. infusion for 10 doses. The maximum tolerated dose was 2 X 10(6) U/m2, with dose-limiting toxicity consisting of fever, diarrhea, and thrombocytopenia. At a well-tolerated dose of 1 X 10(6) U/m2, serum levels of rIL 2 of 30 U/ml were maintained for the duration of the infusion. Such concentrations sustain IL 2-dependent T cell growth in vitro. We observed a significant lymphocytosis in patients receiving 1 X 10(6) U/m2 of rIL 2 following 2 weeks of treatment (p = 0.0035). The expanded T cell pool was polyclonal, as demonstrated by increases in both T4+ and T8+ T cell subsets, and activated, with statistically significant increases in IL 2 receptor (p = 0.043), in the absence of transferrin receptor induction. Proliferating cells were not detected in peripheral blood using flow cytometry. Except for alpha-interferon, no other lymphokines (beta- and gamma-interferon, tumor necrosis factor) were present in serum during treatment. Reversible rises in anti-rIL 2 IgG antibodies occurred, as measured using an enzyme-linked immunosorbent assay. No changes were observed in the T cell mitogenic response to OKT3 and phytohemagglutinin, and no enhancement of cytotoxicity against natural killer-sensitive and resistant targets developed as a consequence of treatment. Except for a partial response in a patient with a myelodysplastic syndrome, no antitumor activity was observed. The in vivo expansion of T cells with the capacity to respond to rIL 2 with enhanced in vitro cytotoxicity against tumor targets provides impetus to ongoing trials exploring different routes and schedules of administration of rIL 2.

Translocation (6;9)(p23;q34) in smoldering leukemia and acute nonlymphocytic leukemia

Two further cases with myeloproliferative disorders (a child with smoldering leukemia and a young male with acute nonlymphocytic leukemia of FAB type M2) and a translocation t(6;9)(p23;q34) are described. Special attention is paid to environmental factors and the early age of onset of patients within the group of leukemias with this specific translocation. In one of our cases a secondary chromosomal anomaly has arisen, which is comparable with another case from the literature.

Intracranial transplantation of human hematopoietic cell lines in nude mice: a preclinical screening model for cytostatic drugs

This study examines the suitability of the intracranial route of transplantation of human cell lines in nude mice for preclinical testing of cytostatic drugs. Tumours were generated by inoculation of human hematopoietic cell lines. Animals in which intramuscularly or intracranially transplanted human tumours developed were treated with cytostatic drugs. Three different cell line generated tumours (T-ALL L735, Hodgkin cell line L540 and Burkitt Lymphoma Line BJAB) were treated with four different drugs (CY, ADM, VCR, VP16). The data show a good correspondence between the results of treatment of intramuscularly and intracranially transplanted tumours. Thus intracranially transplanted tumour in nude mice are suitable for the testing of cytostatic drugs.