Comparative reactivities of esters of oncogenic and nononcogenic purine N-oxides and evidence of the oxidation-reduction reactivity of aromatic nitrenium ions.

Studies on the relative reactivities of esters of oncogenic and nononcogenic members of the purine N-oxide series indicate that, despite similarities in rates of reaction with the solvent, electrophilic cations from oncogenic derivatives are 10- to 100-fold more reactive toward added nucleophiles in vitro than are cations from nononcogenic compounds. The studies provide strong confirmation of an earlier proposal that nitrenium ion contributors of delocalized aromatic cations from 3-acyloxypurines, rather than radical intermediates, are the agents responsible for the oxidizing reactivity of these esters. They demonstrate further that delocalized aromatic nitrenium ions are highly susceptible to reduction by common nucleophiles that are not usually associated with oxidation-reduction reactions. Examples of such behavior with "soft" bases and other oncogenic arylamines indicate the generality of this little recognized property of aromatic nitrenium ions.

Phase I evaluation of a combination of monoclonal antibody R24 and interleukin 2 in patients with metastatic melanoma.

A combination of recombinant human interleukin 2 (rhIL-2) and mouse monoclonal antibody R24 (recognizing the ganglioside GD3) was evaluated in patients with metastatic melanoma in a phase I trial. rhIL-2 was given at a constant daily dose of 1 x 10(6) units/m2 i.v. over 6 h on days 1-5 and 8-12. R24 was given on days 8-12 at four dose levels (1, 3, 8, and 12 mg/m2 daily). Twenty patients were evaluable for toxicity and response, five at each dose level. The toxicity of the combination was not overlapping and generally mild. There was a rebound peripheral blood T-lymphocytosis at the end of treatment increasing with the dose of R24. The median lymphocyte count on day 12 of treatment was 3108 +/- 554/ml in patients treated at R24 doses of 8 and 12 mg/m2 versus 2239 +/- 672/ml at doses of 1 and 3 mg/m2. This evidence and other data suggested that R24 enhanced IL-2-mediated T-cell activation in vivo. Two patients demonstrated increases in R24-mediated antibody-dependent cellular cytotoxicity for GD3-expressing cells during treatment. rhIL-2 appeared to accelerate the development of human anti-mouse antibody; three patients developed human anti-mouse antibody by the fifth day of R24 treatment, earlier than observed in prior studies using R24 alone and one patient during the first week of rhIL-2 alone, prior to R24 treatment. One patient had a partial response in soft tissue sites lasting 6 months and two patients had minor responses. This clinical trial extends the previous observation that R24 enhances lymphocyte proliferation in vitro.

Phase I trial of a mouse monoclonal antibody against GD3 ganglioside in patients with melanoma: induction of inflammatory responses at tumor sites.

Twenty-one patients were entered into a phase I trial to evaluate toxicity, antitumor effects, and biological responses at tumor sites during treatment of R24, an immunoglobulin G3 (IgG3) mouse monoclonal antibody (mAb) against GD3 ganglioside. Toxicity was related to dose of R24. Urticaria and pruritus were the most prominent side effects, with nausea, vomiting, and diarrhea occurring at the highest dose levels. Partial responses were observed in four patients lasting from 6 to 46 weeks, and mixed responses were seen in two patients. Responses occurred as early as 4 weeks and as late as 10 weeks after beginning treatment. Twenty of the 21 patients developed human IgG antibodies against R24. Antimouse Ig antibodies were first detected at a median of 14 days after starting treatment, but three of the four patients who had a partial response developed the antimouse Ig responses later than 20 days. Peak serum levels of R24 were related to dose and ranged from a mean of 0.9 micrograms/mL at the lowest dose level (1 mg/m2/d) to 44 micrograms/mL at the highest dose (50 mg/m2/d). The amount of R24 reaching tumor sites corresponded to the dose administered, and R24 could be detected in tumors as late as 30 days after finishing treatment. Inflammation at tumor sites was observed during treatment. Biopsies of tumors taken before, during, and after treatment revealed that R24 induced deposition of complement components, increased numbers of mast cells with mast cell degranulation, and infiltration of T lymphocytes. These results suggest that treatment with R24 can produce a localized inflammatory response at tumor sites that is capable of producing tumor regression.

Phase I trial of intramuscularly administered tumor necrosis factor in patients with advanced cancer.

A phase I trial of intramuscularly administered recombinant human tumor necrosis factor (rTNF) was conducted in 19 adult patients with advanced solid tumors. The agent was administered daily for up to five consecutive days every other week for two to four courses. Doses of rTNF ranged from 5 to 200 micrograms/m2/d. Dose-limiting toxicities were encountered at doses greater than 100 micrograms/m2/d. Toxicities included tenderness, erythema and induration at the site of injection, fatigue, fever, chills, headache, anorexia, nausea, vomiting, and diarrhea. Moderate to marked reductions in WBC and platelet counts were observed regularly at the highest dose levels, but none were clinically significant. Hepatic enzyme elevation was seen frequently, and two patients developed hyperbilirubinemia. Only one of seven patients treated with doses greater than 100 micrograms/m2/d completed the planned course of therapy. Even at the highest dose levels, serum concentrations of rTNF could only rarely be detected in the serum. No therapeutic responses were observed. The maximal tolerated dose (MTD) of rTNF in this trial was 150 micrograms/m2/d, administered for two courses.

Phase I study of escalating doses of edatrexate in combination with paclitaxel in patients with metastatic breast cancer.

Motivated by the observation of preclinical synergy, a Phase I dose escalation study of edatrexate in combination with a 3-h paclitaxel infusion was performed in patients with advanced breast cancer to determine the maximum tolerated dose (MTD) of edatrexate and the toxicities associated with this combination and to report preliminary observations of efficacy with this novel combination. Thirty-six patients were enrolled in this Phase I trial. Thirty-five eligible patients were treated every 21 days in cohorts of at least three patients and were assessable for toxicity. One patient was ineligible due to hyperbilirubinemia. Stepwise dose escalations of edatrexate were administered until grade >3 nonhematological dose-limiting toxicities were reported. The initial dose level of edatrexate was 180 mg/m2; subsequent cohorts were treated with escalating doses of edatrexate (210, 240, 270, 300, 350, and 400 mg/m2). Edatrexate was administered by i.v. infusion over 1 h. Paclitaxel was administered 24 h later at a fixed dose of 175 mg/m2 as a 3-h infusion with standard dexamethasone, diphenhydramine, and cimetidine premedication. The MTD of edatrexate was reached at the 350 mg/m2 level in this study. Grade 3 diarrhea was seen in one patient at the 300 and 400 mg/m2 dose levels, requiring dose reductions. Two patients experienced grade 4 stomatitis at the 400 mg/m2 dose level and also required dose reduction, establishing the MTD as 350 mg/m2. Grade 3 nausea and vomiting were noted in two of three patients at the highest dose level. Of 35 patients, 4 patients reported grade 3 myalgias and 1 patient reported grade 3 neurosensory complaints, which were seen mostly at the 350 and 400 mg/m2 dose levels; however, 1 patient reported grade 3 myalgias at 180 mg/m2. No cumulative neurotoxicity was observed, and no patient experienced an allergic reaction to paclitaxel. In 23 patients with bidimensionally measurable disease, there were four complete (17%) and seven partial responses, with an overall response rate of 48% (95% confidence interval, 27-69%). All of the responses were seen in patients who had not received prior chemotherapy for stage IV disease. The median duration of response was not assessable because many responding patients went on to receive high-dose chemotherapy treatment with stem cell support. The combination of edatrexate and paclitaxel for treatment of metastatic breast cancer is a feasible and safe regimen. The MTD of edatrexate was 350 mg/m2 when combined with a 3-h infusion of paclitaxel (175 mg/m2) given 24 h later. Activity was noted even among patients who had relapsed shortly after receiving methotrexate- and/or doxorubicin-containing adjuvant regimens. Additional studies evaluating the sequences and dosing schema for this combination are warranted to improve the response proportion and define the duration of the response.

Phase I study of continuous-infusion recombinant macrophage colony-stimulating factor in patients with metastatic melanoma.

Macrophage colony-stimulating factor (M-CSF) is a lineage-specific, homodimeric growth factor that supports the proliferation and maturation of bone marrow progenitors and the survival and function of mononuclear/macrophage cells. In vitro studies have demonstrated antitumor activity of macrophage colony-stimulating factor-treated monocytes against melanoma target cells. A Phase I study was conducted by administering the glycosylated form of the protein to patients with metastatic melanoma as two 7-day continuous i.v. infusions separated by a 2-week rest. Cohorts of three patients per dose level received escalating doses of 10-160 microgram/kg/day. Safety, clinical, and biological effects were evaluated. The infusions were well tolerated with occasional maximum grade 2 nonhematological toxicity. Rapidly reversible thrombocytopenia was the major hematological adverse effect. Its etiology may in part be explained by proliferation and activation of monocyte/macrophage cells in bone marrow samples. Evidence for a biological effect on tumors was suggested by the delayed, complete disappearance of multiple lesions in one patient and a decrease in the size of one marker lesion in a second patient with a mixed response. Fasting serum cholesterol levels decreased during the infusions and may represent an additional therapeutic application for this growth factor.

Synthesis of an N-aminopyrazinonium analogue of cytidine.

An N-aminated pyrazine analogue of cytidine, in which the pyrimidine N(3) ring nitrogen and C(4) amino group were replaced by a C-amino and an N-amino function, respectively, was prepared as a potential deaminase-resistant cytidine antimetabolite. The nucleoside 1,2-diamino-4-beta-D-ribofuranosylpyrazin-2-onium chloride (6) was a mild cytostatic agent but was neither a substrate for nor an inhibitor of mouse kidney cytidine deaminase. It ionized with a lower pKa than expected. The anion did not undergo the dimerization usually observed with N-imino heterocyclic ylides but unerwent hydrolysis of the 2-amino group to yield a 1-aminopyrazine-2,3-dione nucleoside.

Treatment with high dose mouse monoclonal (anti-GD3) antibody R24 in patients with metastatic melanoma.

R24 is a mouse IgG3 monoclonal antibody that reacts with the ganglioside GD3 expressed by melanoma cells and other cells of neuroectodermal origin (e.g. adrenal medulla). Antitumour activity of R24 was demonstrated in initial phase I and pilot trials, but treatment was limited by urticaria at cumulative doses of 400 mg/m2. A trial exploring intensification of the dose of R24 was conducted in eight patients. Planned doses of R24 antibody were 800 and 1200 mg/m2 over 6-8 days by continuous i.v. infusion. All patients received concomitant therapy with hydroxyzine hydrochloride and cimetidine to minimize urticaria. One patient developed anaphylaxis, after which no further therapy was given. All patients developed peripheral blood lymphopenia and marked decreases in serum complement values during treatment, suggesting depletion of two possible effector mechanisms of the antitumour effects of R24. A vascular leak syndrome, manifested by weight gain, oedema and hypotension, was evident in seven patients during the initial 24-36 h of treatment. Serum sickness syndrome was observed in six of seven evaluable patients between days 5 and 8, coincident with the onset of the human anti-globulin response to R24. One patient given 1200 mg/m2 had a minor response (38% reduction in pelvic nodes) lasting 12 months. There was no detectable increase (by immunohistochemical staining) in deposition of R24 within tumour sites at doses used in this trial compared to that observed at doses of 240 and 400 mg/m2. The maximum tolerated dose was 800 mg/m2. Dose-limiting toxicity was manifest as reversible hypertension with end-organ symptoms (chest pain or visual field defects) in patients treated with a dose of 1200 mg/m2.(ABSTRACT TRUNCATED AT 250 WORDS)

Prognostic factors in patients with metastatic malignant melanoma. A multivariate analysis.

BACKGROUND: Current methods to predict survival in patients with advanced, metastatic melanoma are limited. To determine clinical prognostic factors that accurately predict survival in patients with metastatic melanoma, a retrospective analysis was performed. METHODS: Clinical, hematologic, and biochemical pretreatment parameters from 284 patients entered on 18 Phase I and II clinical trials were analyzed to determine their prognostic effect on survival. A multivariate parametric regression based on the Weibull distribution was derived to estimate survival. RESULTS: Multivariate Weibull survival regression analysis showed that a simple model using the logarithm of the pretreatment values of lactate dehydrogenase and serum albumin, dichotomized as high and low, significantly and adequately predicted survival. A more complex multivariate model was also derived that involved the pretreatment platelet count, visceral organ involvement, and gender as additional factors. However, a larger study is needed to statistically validate such a model. CONCLUSIONS: The pretreatment values of serum lactate dehydrogenase and albumin are independent prognostic factors for survival in patients with metastatic melanoma. These two factors can be used to estimate survival of patients with advanced, metastatic melanoma and should be considered when designing melanoma trials in which survival is an endpoint.

A phase II trial of high-dose cisplatin and dacarbazine. Lack of efficacy of high-dose, cisplatin-based therapy for metastatic melanoma.

Cisplatin and dacarbazine are used widely in the treatment of metastatic melanoma. To evaluate high-dose cisplatin and dacarbazine, 32 patients with metastatic melanoma were treated with cisplatin 50 mg/m2 and dacarbazine 350 mg/m2 daily for three days repeated at 28-day intervals. Their median age was 43.5 years (range, 25 to 73 years), and their median Karnofsky performance status was 80% (range, 70% to 100%). Measurable and evaluable disease sites (number of patients) included lymph nodes (22), lung (17), soft tissue (16), liver (13), bone (seven), spleen (four), adrenal gland (three), skin (three), and other sites (five). Patients received a median of two cycles of therapy (range, one to eight cycles). Thirty patients were evaluable for response. No complete responses were observed. Five patients had a partial response (17%; 95% confidence interval, 3% to 30%) for 16+, 12+, 7, 6.5, and 3 months. Responding sites of disease included lymph nodes (five of 22), lung (three of 17), and soft tissue (two of 16). Hematologic toxicity (Grade greater than or equal to 3) included neutropenia (16 of 32 patients, 30 of 90 cycles), thrombocytopenia (eight of 32 patients, 12 of 90 cycles), and anemia (five patients). Nine episodes of neutropenia and fever were seen in four patients; two had bacteremia. Nonhematologic toxicity (Grade greater than or equal to 3) included hypotension (two patients), nausea and vomiting (four), neuropathy (two), ototoxicity (four), and hypomagnesemia (nine). The low objective response rate and severe toxicity of this regimen preclude its standard use in patients with metastatic melanoma. A review of cisplatin-based therapy in metastatic melanoma suggests that there is no dose-response relationship. The use of high-dose cisplatin (greater than 100 mg/m2) in the treatment of metastatic melanoma is not recommended.