Phase II clinical trial of arsenic trioxide with liposomal doxorubicin, vincristine, and dexamethasone in newly diagnosed multiple myeloma.

In patients with multiple myeloma, there is preclinical justification to combine arsenic trioxide (ATO and As(2)O(3)) with DVd (Doxiltrade mark, vincristine, and dexamethasone) for newly diagnosed patients. Eleven patients on this phase II trial received 0.15 mg/kg of ATO for five consecutive days followed by four cycles of DVd plus ATO with the ATO at 0.25mg/kg IV twice per week. The most common grade 3 toxicities were hyperglycemia, hyponatremia, and hypocalcemia. There were four partial and no complete responses. We could not demonstrate that the addition of ATO with this schedule improved the response rate of MM to DVd.

Complement depletion accelerates the clearance of immune complexes from the circulation of primates.

Binding of immune complexes (IC) to erythrocytes in vitro is the result of interaction between C3b sites on the IC, and complement receptors type I (CRI) expressed on primate erythrocytes. Recent evidence indicates that primate erythrocytes can also rapidly bind large, preformed IC in vivo. This study was undertaken to determine if the binding of IC to baboon erythrocytes in vivo is complement dependent and to examine the effect of complement depletion on IC clearance from the circulation. The results indicate that complement depletion in vivo reduced the binding of IC to erythrocytes. There was relatively little binding of IC to leukocytes in both the complement-depleted and complement-repleted condition. Thus, the majority of IC not bound to erythrocytes remained free in the plasma and, consequently, IC infusion during the complement-depleted state resulted in increased plasma IC concentrations. This was associated with a rapid disappearance of IC from the circulation. By contrast, in the normal or complement-repleted state, a large fraction of the IC became bound to erythrocytes during IC infusion, which resulted in lower plasma IC concentrations. Under these conditions, a more gradual rate of disappearance of IC from the circulation was observed. The relatively abrupt clearance of IC from the circulation in the complement-depleted state could not be accounted for by increased hepatic or splenic uptake. These data indicate that, in contrast to previous studies in nonprimates, complement depletion in primates results in accelerated removal of IC from the circulation. This suggests that factors such as hypocomplementemia and deficient expression of erythrocyte CRI, which are known to occur in certain IC-mediated diseases, may promote IC uptake by organs vulnerable to IC-mediated injury.

Phase I evaluation and pharmacokinetic study of pyrazine-2-diazohydroxide administered as a single bolus intravenous injection in patients with advanced solid tumors.

The sodium salt of pyrazine-2-diazohydroxide (PZDH; NSC 361456) was identified as an active congener of the antitumor lead pyridine-2-diazotate with enhanced chemical stability under physiological conditions. In a phase I trial of PZDH administered as a single i.v. bolus injection, 19 patients with refractory solid tumors received 44 courses of therapy at dose levels ranging from 50 to 350 mg/m2. No objective responses to PZDH were noted. Myelosuppression characterized by prolonged, delayed onset leukopenia and thrombocytopenia was the dose limiting toxicity. A maximum tolerated dose of 350 mg/m2 was identified for this treatment schedule. Nonhematological toxicity was limited to severe nausea and vomiting, experienced by all patients treated at the lower doses, although reasonably well controlled when antiemetics were given prior to chemotherapy. The plasma pharmacokinetics of PZDH was evaluated following a single course of therapy in 16 patients. Drug levels were monitored using a specific capillary gas chromatographic assay with a 1-ng/ml lower limit of quantitation. In patients treated with doses greater than 50 mg/m2, the concentration of PZDH in plasma declined in a distinctly triexponential manner and remained above 1.5 ng/ml for at least 8 h. However, the initial decay phase, characterized by a harmonic mean half-life of 3.9 +/- 3.5 (SD) min (range, 2.2-6.3 min), was the primary determinant of drug disposition, as indicated by its 85.5-93.1% contribution to the area under the plasma concentration-time profiles from time zero to infinity. The harmonic mean terminal half-life increased with escalations in dose from 2.7 +/- 0.8 h (n = 2) at 100 mg/m2 to 8.5 +/- 3.0 h at 350 mg/m2 (n = 6). Total plasma drug clearance was very similar in patients treated with doses of 50-250 mg/m2, exhibiting a mean value of 42.5 +/- 7.8 liters/h/m2 (n = 10); however, it was significantly lower at the 350 mg/m2 dose level, 27.2 +/- 6.6 liters/h/m2 (n = 6; P < 0.002), denoting a departure from linear pharmacokinetic behavior. The rather low steady state apparent volume of distribution, which ranged from 6.0 +/- 1.5 (50 mg/m2, n = 2) to 12.7 +/- 8.0 (350 mg/m2, n = 6) liters/m2, was indicative of limited distribution of the drug into body tissue. The absence of objective antitumor effects should not discourage continued evaluation of PZDH against solid tumors selected for probable sensitivity as indicated by preclinical testing. A dose of 250 mg/m2 on a single i.v. bolus schedule is recommended for these phase II trials.

Phase II trial of 9-beta-D-arabinofuranosyl-2-fluoroadenine 5'-monophosphate in non-Hodgkin's lymphoma: prospective comparison of response with deoxycytidine kinase activity.

A phase II study of 9-beta-D-arabinofuranosyl-2-fluoroadenine 5'-monophosphate was done in non-Hodgkin's lymphoma with a loading dose/continuous intravenous infusion schedule, consisting of a 20 mg/m2 loading dose followed by a continuous i.v. infusion of 30 mg/m2/24 h for 48 h. The loading dose was held constant while the continuous i.v. dose was escalated or decreased as appropriate for toxicity. Twenty-six patients were entered on the study; 25 are evaluable for response. The patients' median age was 61 years (range 25 to 73); their mean performance status was 1.1. They had received a mean of 2.6 prior chemotherapeutic regimens, and six also had prior radiation therapy. There was one complete response lasting 9+ months, and there were seven partial responses lasting 20, 13, 11, 11, 10, 5, and 2 months (response rate 32%). Toxicity was acceptable and consisted mainly of myelosuppression. 9-beta-D-arabinofuranosyl-2-fluoroadenine 5'-monophosphate is dephosphorylated in vivo and then is thought to be activated intracellularly to 9-beta-D-arabinofuranosyl-2-fluoroadenine 5'-triphosphate. The rate-limiting enzyme is deoxycytidine kinase. Deoxycytidine kinase activity was determined on pretreatment tumor samples for correlation with response. There was no difference between the values for responders and nonresponders. There was a trend for higher values in more malignant histological subtypes.

Pentostatin in the treatment of advanced hairy cell leukemia.

2'-Deoxycoformycin (pentostatin [dCF]), a potent inhibitor of adenosine deaminase (ADA), was administered in a biweekly low-dose (2 to 4 mg/m2) intravenous (IV) schedule to patients with advanced hairy cell leukemia. Twenty-three patients were treated, including 12 patients previously treated by splenectomy and five patients treated with interferon. Twenty-one of 23 patients had objective responses, including 20 who achieved a complete remission (CR). Responses occurred rapidly, with an average time to CR of 5.4 months. Treatment was not continued once CR was achieved, and 15 of 20 patients remain in remission with an average duration of 12.6 months. CRs were achieved in both patients previously treated with interferon (three of five) and patients with marked splenomegaly (three of three). Relapses, when seen, have occurred in the bone marrow alone and the one patient who required retreatment was reinduced into CR. Toxicity has been mild and reversible, with nausea and vomiting, conjunctivitis, and skin rash as the main complications of treatment. dCF is the most effective single agent in the treatment of hairy cell leukemia, inducing a high percentage of CRs in all subgroups. Two multiinstitutional trials are now underway to compare its effectiveness v alpha interferon.

Immunosuppressive effects of pentostatin.

The immune function of patients with hairy cell leukemia (HCL) and solid tumors was evaluated before and after treatment with the investigational drug 2'-deoxycoformycin (pentostatin; dCF). Thirteen HCL patients received doses of dCF of 2 to 4 mg/m2 intravenously at 2- to 6-week intervals for up to 15 courses. After completion of treatment, 12 of 13 patients had resolution of severe monocytopenia and five of nine had normal monocyte antibody dependent cellular cytotoxicity. There was statistically significant depression of total lymphocytes, T cells, and B cells. Evaluation of T subsets showed a decrease in CD4+ cells. Immunoglobulin G (IgG) in sera were decreased from baseline, while IgM and IgA were unaffected. There was no significant effect on skin-test reactivity or large granular lymphocyte numbers. Lymphoblastic transformation was variably affected. Natural-killer (NK) cell function was improved or unchanged after dCF treatment. Reevaluation of seven patients at 21 to 119 weeks after receiving dCF demonstrated that recovery to normal T- and B-cell numbers and subsets does occur. Five solid tumor patients were given dCF at 4 mg/m2 intravenously at 1- to 2-week intervals for up to five courses. There was significant reduction in T cells, B cells, CD4+, and CD8+ cells with no statistically significant effect on the other immune parameters. We conclude that low doses of dCF can cause persistent immunosuppression though recovery may occur after the drug is stopped. In patients followed after completion of dCF, there was no associated increase in second malignancies or unusual infections.

Evaluation of topotecan in resistant and relapsing multiple myeloma: a Southwest Oncology Group study.

PURPOSE: Topotecan is a topoisomerase I inhibitor with antitumor activity against hematologic and solid tumor malignancies. We evaluated its activity in refractory and relapsing multiple myeloma patients who had received one prior chemotherapeutic regimen. PATIENTS AND METHODS: Toptecan 1.25 mg/m2/d was administered as a 30-minute infusion for 5 days repeated every 3 weeks. Granulocyte colony-stimulating factor (G-CSF) 5 microg/kg/d subcutaneously was administered after the first course of treatment if neutropenia was dose-limiting. RESULTS: Forty-six patients entered the study, with 43 patients eligible. The major toxicity was granulocytopenia with grade 3 or better occurring in 40 of 43 patients treated; 21 of 43 patients developed grade 3 or greater thrombocytopenia. Other significant toxicity included mild nausea in 23 patients and mild vomiting in 13 patients. The overall response rate (partial response or better) was 16% (95% confidence interval, 7% to 31%), with responses occurring in both relapsed and refractory patients. Responses have lasted 70 to 477+ days, with a median progression-free survival duration of 13 months and median survival time of 28 months. CONCLUSION: Topotecan has activity in refractory and relapsing multiple myeloma. Future investigation of topotecan in multiple myeloma including combination therapy and the study of other topoismerase I inhibitors is warranted.

Low-dose deoxycoformycin in lymphoid malignancy.

Deoxycoformycin (dCF), a potent inhibitor of adenosine deaminase (ADA), was explored for its antineoplastic potential in 28 patients with advanced lymphoid malignancy. Both normal and malignant B lymphocytes have low levels of ADA activity, and low doses of dCF profoundly inhibit this enzyme in the peripheral blood of patients with chronic lymphocytic leukemia (CLL). The low doses of dCF administered in this trial (4 mg/m2) were not associated with prohibitive toxicity. Five of 28 patients had an objective response. Four additional patients had clinical improvement. No significant difference in the pretreatment ADA activity existed between responding patients and treatment failures. The demonstration of responses to dCF following failure on standard alkylating agents suggests that dCF may not be cross-resistant with current agents used to treat CLL. Additional studies should be pursued using low-dose dCF in patients with advanced malignancy.

Treatment of hairy cell leukemia: the Ohio State University experience with deoxycoformycin.

Twelve evaluable patients with progressive hairy cell leukemia were treated with deoxycoformycin at a dose of 4 mg/m2 every 2 weeks. Five patients had not been splenectomized, and one had failed to respond to interferon-alpha. Complete remission, as defined by absence of hairy cells in the bone marrow and normalization of the peripheral blood and regression of splenomegaly, was obtained in 11 of 12 patients (92%). These patients have remained in unmaintained remission for 1+ to 13 months with an average of 7.5 months. Two of these patients had a bone marrow relapse at 8 and 12 months, respectively. During treatment the monocytopenia corrected, and, after complete remission was obtained, marrow was aspirable. Toxicity was mild and reversible. There were no significant infections associated with this treatment. It was of interest that we could treat two patients with creatinine clearance of 50 and 60 ml/min using lower doses (and 2-3 mg/m2) than our conventional therapy of 4 mg/m2 every 2 weeks. They obtained a complete remission after 6 and 10 treatments, respectively. Low-dose deoxycoformycin has proven to be an excellent treatment for hairy cell leukemia.

Glucose metabolism of hairy cells.

Hairy cell leukemia is a malignant B-cell disorder characterized by splenomegaly and pancytopenia. The malignant cell is morphologically unique and characterized by fine cytoplasmic projections. Although studies of the cell have revealed important information about its proliferative capacity, cell surface, and membrane composition, less is known about the metabolic characteristics of the cell. We have previously investigated the oxidative metabolism of the hairy cell and have suggested that hairy cells might have a unique glucose metabolism compared to normal lymphocytes. This is indicated by a high rate of [6-14C]glucose oxidation in short-term culture consistent with an active Kreb's cycle and a high ratio of [6-14C]glucose oxidation to [1-14C] glucose oxidation. In this study, we evaluated an additional group of patients with hairy cell leukemia prior to or after treatment with the experimental drug 2'-deoxycoformycin (dCF). We found that in seven of eight patients the leukemic cells had a pattern similar to that previously described and that all of these seven patients had a significant response to therapy. The cells of the eighth patient had minimal Kreb's cycle activity, and at the time of study the patient was resistant to therapy with dCF. The metabolic activity of hairy cells may distinguish them from other lymphoid populations and may be a marker for sensitivity to dCF.

The use of topoisomerase I inhibitors in multiple myeloma.

The standard treatment of multiple myeloma is systemic chemotherapy. Despite 30 years of drug development in myeloma, there are no new drug regimens significantly superior to melphalan and prednisone. In addition, phase II studies of new drugs in myeloma have been disappointing, with low response rates and no prolongation in survival. The topoisomerase I (topo I) inhibitors are a new class of anticancer agents with a wide spectrum of activity in human malignancies. Recent evaluation of the topo I inhibitor topotecan demonstrated activity in advanced myeloma, suggesting a possible role for these drugs in the treatment of this disease. Further evaluation of the mechanisms of resistance to topo I inhibitors, study of combination therapy with topotecan, and evaluation of other topo I poisons in multiple myeloma is proposed.

Phase II trials of pentostatin (Nipent) in hairy cell leukemia.

Hairy cell leukemia (HCL) is a chronic lymphoproliferative disease of B-cell origin manifested by pancytopenia and splenomegaly. Before 1980 the only effective treatment for HCL was splenectomy, which resolved the cytopenia but did not eliminate the disease from the bone marrow. In addition, the majority of patients progressed after splenectomy and required further treatment. Pentostatin (Nipent; SuperGen, San Ramon, CA) is a purine antimetabolite that was found in phase I studies to induce profound lymphocytopenia Although in vitro studies suggested that T lymphocytes were most sensitive to pentostatin, patients with B-cell chronic lymphatic leukemia and low-grade non-Hodgkin's lymphoma responded to treatment in the initial phase I trials. Due to evidence that the drug was effective in lymphoproliferative disease, patients with HCL were treated with pentostatin. The promising initial results led to phase II studies in both untreated and previously treated patients. These studies demonstrated that pentostatin was highly effective as a single agent, with complete responses seen in 60% to 90% of patients. These responses were durable without maintenance chemotherapy and were seen in patients previously treated with interferon or chemotherapy. Toxicity was usually mild, with nausea and skin rashes predominating. When seen, infections resulting from neutropenia occurred early in treatment. The high response rates and low toxicity suggest that pentostatin should be considered as one of the standard treatments for HCL.

A phase III comparison of high dose ARA-C (HIDAC) versus HIDAC plus mitoxantrone in the treatment of first relapsed or refractory acute myeloid leukemia Southwest Oncology Group Study.

The aim of this study is to determine whether the addition of mitoxantrone to high dose cytarabine improves the outcome of treatment in patients with relapsed or refractory acute myeloid leukemia (AML). One hundred and sixty-two eligible patients, 14-76 years of age, with AML either in first relapse or that failed to respond to initial remission induction therapy, with no CNS involvement were randomized to receive therapy with cytarabine 3 gm/M2 i.v. over 2 h every 12 h for 12 doses on days 1-6 (Arm I) (HIDAC); or HIDAC plus mitoxantrone 10 mg/M2 i.v. daily on days 7 9 (Arm II) (HIDAC + M). Patients achieving complete remission were treated with three courses of consolidation including HIDAC (Ara-C 3 gm/M2 i.v. 12 h days 1 3; 2 gm/M2 over age 50) alone (ARM I) or with mitoxantrone (10 mg/M2 i.v. day 1) (ARM II). Among 162 patients (81 HIDAC, 81 HIDAC + M) evaluated for induction toxicity, there were 10 (12%) induction deaths with HIDAC and 13 (17%) with HIDAC + M (2-tailed P = 0.65). Most early deaths were due to infection and/or hemorrhage. Among 162 patients evaluated for responses to induction therapy, 26/81 (32%) HIDAC and 36/81 (44%) HIDAC + M patients achieved complete remission (two-tailed P = 0.15). Although this difference was not statistically significant in univariate analysis, it was after adjusting for the effects of WBC and PMN percentage in multivariate analysis (P=0.013). Median survivals from study entry were 8 months (HIDAC) and 6 months (HIDAC + M); 2-tailed logrank P = 0.58. Among 48 patients registered for consolidation, the median disease-free survivals from that registration were 8 months with HIDAC and 11 months with HIDAC + M (P = 0.60). There were three treatment-related deaths during consolidation (1 HIDAC, 2 HIDAC + M), all due to infections. In this randomized trial, the addition of mitoxantrone to high-dose cytarabine was associated with a trend toward a higher CR rate. There was less evidence for an advantage in disease-free or overall survival, although any such conclusion is limited by the size of the study.

A phase I study of induction chemotherapy for older patients with newly diagnosed acute myeloid leukemia (AML) using mitoxantrone, etoposide, and the MDR modulator PSC 833: a southwest oncology group study 9617.

Older patients with acute myelogenous leukemia (AML) have overexpression of P-glycoprotein (Pgp+), and this has been shown to correlate quantitatively with therapeutic outcome. Since Pgp-mediated efflux of cytotoxic drugs can be inhibited by the cyclosporine analogue, PSC 833, we investigated the use of this agent with a 5-day mitoxantrone/etoposide regimen in patients over age 55 with newly diagnosed AML. Previous studies suggested a 33% incidence of grade IV/V non-hematologic toxicity with the use of mitoxantrone 10 mg/M(2) and etoposide 100 mg/M(2), each for 5 days, in this patient population. Since PSC 833 alters the pharmacokinetic excretion of MDR-related cytotoxins, this phase I dose-finding study was performed to identify doses of mitoxantrone/etoposide associated with a similar 33% incidence of grade IV/V non-hematologic toxicity, when given with PSC 833. Mitoxantrone/etoposide (M/E) doses were escalated in fixed ratio from a starting dose of M: 4 mg/M(2) and E: 40 mg/M(2), to M: 7 mg/M(2) and E: 70 mg/M(2), in successive cohorts of eight patients each. PSC 833 was well tolerated and the MTD of this M/E regimen with PSC 833 in this population was M: 6 mg/M(2) and E: 60 mg/M(2). The complete response (CR) rate for all patients was 50% (15/30) and was considerably higher for de novo than for secondary AML. These data suggest that the addition of PSC 833 to an M/E regimen for older patients with untreated AML is well tolerated but requires a reduction in M/E dosing to avoid increased toxicity.

Detection of circulating immune complexes by a Clq/protein A-ELISA during the preneoplastic stages of feline leukemia virus infection.

A microscale ELISA immune complex assay which utilized a solid phase C1q and a Protein A-peroxidase enzyme conjugate is described. This ELISA was used to detect and quantitate circulating immune complexes (CIC) during the initial feline leukemia virus infection. Significant increases in CIC were seen in the cats which were transiently infected at weeks three through eight after viral exposure. A persistent elevation in CIC was observed in the one cat which developed a persistent viremia. The addition of EDTA to the serum strongly interfered with this assay.

Feline complement dependent binding in the Raji cell assay is insufficient for the quantitation of immune complexes.

A comparison was made of the binding of radiolabeled heat aggregated cat immunoglobulin G (125I-ACG) to Raji cells using normal or heat-inactivated cat or human serum. The binding with normal or heated cat serum, as well as heated human serum were essentially identical. The binding using normal human serum was 2.5- to 3-fold greater than observed with heated human serum. These results suggest that feline complement associated with 125I-ACG does not bind to Raji cells via complement receptors, but only by receptors for the Fc portion of IgG. Human serum and 125I-ACG can bind to both Fc and complement receptors on Raji cells.

Phase II trial of merbarone in pancreatic carcinoma. A Southwest Oncology Group study.

Twenty-nine patients with advanced pancreatic adenocarcinoma were treated with merbarone, utilizing a daily intravenous schedule for 5 days. Only two partial responses of short duration were observed. The major toxicities were renal, with an increase in creatinine or proteinuria in 17 patients, and mild to moderate nausea and vomiting seen in 22 patients. Merbarone in this dose and schedule has minimal activity in pancreatic cancer.

Evaluation of the role of oxygen radicals in polymorphonuclear leukocyte aggregation.

oxygen radicals have been shown to alter granulocyte function by injury to the cell membrane or cytoskeleton. We have investigated the effect of such injury on the aggregation of granulocytes upon C5a or PMA stimulation. Granulocyte aggregation was not altered in the presence of the oxygen radical scavengers SOD, catalase, mannitol, or benzoate. To test whether oxygen radicals were required for aggregation, we evaluated three patients with chronic granulomatous disease of childhood. The response of PMNs from these patients was no different from controls. Hydrocortisone, an inhibitor of both granulocyte aggregation and oxygen radical generation, was then studied to decide whether its impairment of radical production contributed to its effect on aggregation. Five times the concentration of hydrocortisone needed to inhibit radical generation was required to impair aggregation by 50%. In addition, hydrocortisone was able to impair the aggregation of the PMNs of a patient with chronic granulomatous disease. These data suggest that oxidative injury to the cell membrane or cytoskeleton does not significantly contribute to the aggregation of granulocytes. In addition, inhibitors of aggregation, such as hydrocortisone, work through mechanisms other than by scavenging radicals.

Effects of treatment with cobra venom factor on experimentally induced feline leukemia.

Five- to six-month-old specific-pathogen-free cats were exposed to cobra venom factor (CVF) alone (4 cats), Rickard feline leukemia virus (FeLV; 9 cats), or CVF and FeLV (6 cats). Host-virus relationships were evaluated by monitoring the development of viremia, production of antibody against feline oncornavirus-associated cell membrane antigen, and amount of circulating immune complexes (CIC). Exposure to CVF induced complement depletion, which lasted 8 to 15 days. However, complement depletion did not promote the development of persistent viremia nor alter the production of antibody to feline oncornavirus-associated cell membrane antigen or CIC. Results indicated that the complement system did not protect cats during their initial exposure to FeLV and that an intact complement system was not necessary for the development of antibody against feline oncornavirus-associated antigen or for the formation of CIC.