Induction of tolerance in peripheral T cells with monoclonal antibodies

Our goal has been to develop ways to tolerize the mature immune system to any defined antigen. In this report we show that peripheral (post-thymic) T cells of mice can become tolerant to a range of antigens (human and rat immunoglobulins, and bone marrow and skin grafts that differ at multiple minor transplantation antigens). In the case of human gamma globulin (HGG), this required that the antigen be given under the cover of a short course of non-depleting anti-CD4 antibody, while for tolerance to skin and marrow grafts anti-CD8 antibody was also required. Tolerance to HGG could be reinforced by repeated injections of HGG, but was lost in the absence of any further exposure to antigen. This reversal of tolerance with time was due to new T cells being exported from the thymus, as it was not observed in tolerized, adult thymectomized mice. In contrast, tolerance to marrow and skin grafts was permanent, presumably because the established grafts acted as a continuous source of antigen to reinforce the tolerant state. Tolerance could not be broken by the infusion of unprimed spleen cells and in one example (tolerance to Mls-1a) there was clear evidence that specific peripheral T cells were anergic. We propose that anergic cells may themselves participate in reinforcing the tolerant state by competing at sites of antigen presentation.

3-Deazaguanine: report of a phase I trial and drug-related cardiac toxicity

3-Deazaguanine (Dezaguanine), a purine antimetabolite, was evaluated in a phase I trial in 42 patients with advanced solid tumors. Dezaguanine was given as a weekly intravenous infusion for three consecutive weeks of a four-week cycle. The dose ranged from 30 to 2000 mg/m2; no consistent dose-limiting hematologic or gastrointestinal toxicity was observed. Some patients reported brief episodes of burning at the infusion site or transient facial flushing immediately following the administration of dezaguanine. Three patients experienced cardiac toxicity. Two patients, at doses of 1130 and 2000 mg/m2 respectively, developed congestive heart failure. In one case the heart failure was fatal; the second patient recovered within 8 weeks. The third patient had a progressive fall in left ventricular ejection fraction but did not develop clinical evidence of heart failure before his death from progressive cancer two months later. Postmortem cardiac pathology in the two patients who died early following therapy revealed nonspecific interstitial fibrosis without inflammatory cell infiltrates. The myocardium of the third patient, who died 20 months after receiving dezaguanine, was normal. Electron microscopic analysis of myocardium from the first patient did not show myofibrillar loss or mitochondrial disorganization characteristic of anthracycline cardiomyopathy. Due to the probable cardiotoxicity of dezaguanine in this study and the lack of objective antitumor response, further development of this agent has been discontinued.

A prospective, randomized evaluation of the treatment of colorectal cancer metastatic to the liver

Over a 4-year period (1982 to 1986), 91 patients with solitary or multiple metastases from colorectal cancer were stratified, based on findings at laparotomy, to one of three groups and then prospectively randomized to one of two treatment arms within each group. Group A patients had solitary resectable metastases, group B patients had multiple, resectable metastases, and group C patients had multiple, unresectable metastases. Patients were randomized to one of two treatment arms within a group: group A-arm A1: resection only, arm A2: resection and continuous hepatic artery infusion (CHAI) of fluorodeoxyuridine (FUdR); group B-arm B1: resection and CHAI, arm B2: CHAI only; group C-arm C1: CHAI, arm C2: systemic fluorouracil followed by CHAI. Median time to failure (TTF) was 31.8, 11.1, and 8.8 months for groups A, B, and C, respectively. Arm A2 had an improved TTF when compared with arm A1 (P = .03). Median survival correlated with extent of disease and was 37.3, 22.4, and 13.8 months for groups A, B, and C, respectively. Survival was not changed by treatment variation (arms) within each group. Two- and 5-year cumulative survivals for groups A, B, and C were 72.7% and 45.4%; 45.8% and 16.7%; and 31.7% and 3.2%, respectively. In patients with multiple metastases (groups B and C), those patients whose original tumor was a Dukes' B had a significantly improved TTF and survival over those patients whose tumor was a Dukes' C (P less than or equal to .02).

Prospective randomized comparison of fluorouracil versus fluorouracil and high-dose continuous infusion leucovorin calcium for the treatment of advanced measurable colorectal cancer in patients previously unexposed to chemotherapy

Seventy-nine patients with advanced, measurable, metastatic colorectal cancer previously unexposed to chemotherapy were randomly assigned to treatment with either fluorouracil (FUra) administered intravenously at a dose of 370 mg/m2/d for 5 days or the combination of FUra in the same dose and schedule with high-dose continuous infusion leucovorin calcium (500 mg/m2/d) beginning 24 hours before the first dose of FUra and continuing for 12 hours after the completion of FUra therapy. Patients whose disease progressed on treatment with FUra alone were, if eligible, crossed over to receive leucovorin and FUra. Three patients on the FUra plus leucovorin arm of the study were excluded from the analysis because they did not meet eligibility requirements. The treatment arms were well balanced for prognostic criteria including performance status, age, prior radiotherapy, distribution of metastatic sites, and on-study carcinoembryonic antigen (CEA), lactic dehydrogenase, and serum albumin. FUra plus leucovorin was superior to FUra alone for response (P = .0019) and for time to progression or death (log-rank, P = .045). Response rates were 16 of 36 (44%) versus five of 40 (13%), and median time to progression or death was 164 versus 120 days in the two arms of the trial, respectively. Overall survival, however, while longer in the FUra and leucovorin arm was not significantly so. An analysis of the toxicities experienced by the patients in the two treatment groups showed that, except for significantly more stomatitis in the leucovorin arm of the study, the side effects experienced by patients treated with either regimen were comparable. These results suggest that the efficacy of FUra in patients with advanced, measurable, metastatic colorectal cancer can be enhanced significantly by administration of a continuous high-dose infusion of leucovorin calcium.

Differential oncogene amplification in tumor cells from a patient treated with cisplatin and 5-fluorouracil

Peritoneal cells were derived from a patient (PK) with adenocarcinoma of the colon during the course of cisplatin/5-fluorouracil (5-FUra) treatment. Resistance to cisplatin and 5-FUra, characterized by a lack of response to chemotherapy and continued growth of the tumor, was concomitantly associated with a 2-4-fold increase in DNA copy number for dTMP synthase and dihydrofolate reductase. There was a corresponding amplification in DNA copy number of the c-myc (2X), H-ras (4X), and c-fos (15X) oncogenes. Cytogenetic studies revealed an iso (13q) chromosome, but failed to show any double minutes or homogeneously staining regions. In addition, drug-resistant tumor cells from PK and another patient (HG) displayed enhanced expression of dTMP synthase, c-fos and DNA polymerase beta when compared to normal colon tissue and the HCT8 human colon carcinoma cell line. These results suggest that elevated oncogene DNA and gene expression may be involved in the development of cisplatin resistance.

Treatment of metastatic malignant melanoma with trimetrexate: a phase II study

Trimetrexate glucuronate, a nonclassical antifolate, was administered to 14 patients with recurrent and progressive metastatic malignant melanoma. Thirteen patients were evaluable for response and toxicity. Five patients had received prior treatment consisting of immunotherapy (one patient), immunotherapy plus radiotherapy (one patient), radiotherapy (one patient), chemotherapy (one patient), or radiotherapy and chemotherapy (one patient). The starting dose of trimetrexate was 8 mg/m2 given as an intravenous bolus daily for 5 consecutive days of a 21-day cycle. Subsequent cycles of therapy were escalated by 25% based on individual patient tolerance. A median of two courses of trimetrexate was administered (range 1-4). No patient demonstrated a measurable objective response to this treatment regimen. Trimetrexate was well-tolerated; toxicity was mild and consisted primarily of myelosuppression or nausea and vomiting. At the dose level and schedule used in this study, trimetrexate was not effective for the treatment of disseminated malignant melanoma.

Organization of cortical afferent and efferent pathways in the white matter of the rat visual system

Fibers forming reciprocal connections between the dorsal lateral geniculate nucleus and primary visual cortex run in separate tracts in the white matter. The corticofugal fibers are organized into bundles which project through the coronal plane at an oblique angle. We have examined the organization of corticofugal fiber tracts within the white matter of the rat using cortical slices which encompassed the predicted trajectory of these fiber bundles. Field potentials were evoked in layer VI of visual cortex by focal stimulation of subcortical white matter using microbipolar electrodes. Two major responses were elicited: a short-latency and a longer-latency response. The short-latency response was elicited in the superficial strata of white matter with proximal stimulation sites and was obtained in deeper strata for more distant, lateral sites. The longer-latency response was associated with superficial strata in white matter at both proximal and distant stimulation sites. Based on the electrophysiological properties and the white matter location for eliciting these responses, it is likely that the short-latency response is due to antidromic activation of corticogeniculate fibers, whereas the longer-latency response probably arises from orthodromic activation of geniculocortical fibers. These findings provide an electrophysiological demonstration that cortical afferent and efferent pathways are segregated within the white matter and that they can be selectively activated by focal stimulation. The fact that the fiber bundle model successfully predicted the trajectory of corticofugal fibers provides additional support for this model of white matter organization. A double labeling technique which combined orthograde axonal transport and neuronal degeneration was used to examine the topographic arrangement of corticofugal fibers in the white matter.(ABSTRACT TRUNCATED AT 250 WORDS)

Combination chemotherapy with cytosine arabinoside (Ara-C) and cis-diamminedichloroplatinum (CDDP) for squamous cancers of the upper aerodigestive tract

Based on the demonstration of in vitro and in vivo synergy between cytosine arabinoside (Ara-C) and cis-diamminedichloroplatinum (CDDP), we designed a Phase II trial of Ara-C plus CDDP for patients with advanced squamous cancers of the head and neck and esophagus. Sixteen patients were treated on a unique schedule of continuous-infusion Ara-C, 30 mg/m2/day over 72 h, plus CDDP, 30 mg/m2/day at hours 12, 36, and 60 of the Ara-C infusion. The objective response rate was 38% (95% confidence limits 14-62%), with two patients achieving complete clinical and radiographic response (9 and 27+ months duration) and four partial responses (median duration 4 months, range 1-7 months). There was no CDDP-related nephro- or neurotoxicities, but a flu-like syndrome of anorexia and asthenia was common. Myelosuppression was the dose-limiting toxicity, necessitating Ara-C dose adjustments in 11 cycles of therapy and leading to fatal sepsis in one patient. We conclude that the activity of this combination, though comparable to that of other CDDP-containing regimens, offers no significant therapeutic advantage, and given the excessive hematologic toxicity, should not be investigated further.

Refractory metastatic breast cancer: salvage therapy with fluorouracil and high-dose continuous infusion leucovorin calcium

Sixty women with metastatic breast cancer refractory to at least one chemotherapeutic regimen were treated with fluorouracil (FUra) and high-dose continuous infusion folinic acid (leucovorin calcium). One complete remission lasting 8.7 months and nine partial remissions ranging in duration from 1.3 to 12.8 months were observed, for an objective response rate of 17% (95% confidence interval for response, 8% to 27%). Nine of the ten responding patients had metastatic disease that had objectively progressed on previous chemotherapy with a FUra-containing regimen. This program was well tolerated, with toxicities consisting mainly of stomatitis and granulocytopenia. These results suggest that augmentation of the reduced folate levels of metastatic breast carcinomas may enhance the effectiveness of the fluoropyrimidines in this disease.

Etoposide (VP-16) and cytosine arabinoside in the treatment of relapsed small-cell lung cancer

Seventeen patients with small-cell lung cancer refractory to combination chemotherapy were entered in a study of VP-16 and infusional Ara-C. All patients were evaluable for response and 14 were evaluable for toxicity (three deaths that occurred after the first cycle of therapy were due to progressive tumor, and toxicity could not be evaluated in these three patients). Ara-C was given as a continuous intravenous infusion of 45 mg/m2/day for 72 h; VP-16 was given as three daily intravenous bolus doses of 50 mg/m2 at hours 12, 36, and 50 of the 72-h Ara-C infusion. Because of excessive myelotoxicity in the first six patients, the last 11 patients began treatment at a lower dose of Ara-C, 25 mg/m2/day. Six of 17 patients had previously been exposed to VP-16 as part of their initial chemotherapy regimen. The 17 patients received 32 cycles of therapy. Myelotoxicity was severe, with nadir granulocyte counts less than 500/microliters or platelet counts less than 30,000/microliters in four treatment cycles (including two at the lower Ara-C dose). No patient experienced an objective response to this therapy. We conclude that the combination of VP-16 and infusional Ara-C at these doses is excessively toxic and does not warrant further investigation in refractory small-cell lung cancer.

Fetal hemoglobin gene activation in a phase II study of 5,6-dihydro-5-azacytidine for bronchogenic carcinoma

5-Azacytidine and several of its analogues are known to inhibit DNA methylation, alter gene expression, and inhibit cell growth. We report a Phase II study in which we investigated the antineoplastic activity of 5,6-dihydro-5-azacytidine and its induction of fetal hemoglobin synthesis when given by a 5-day continuous i.v. infusion of 1650 mg/m2/day that was repeated every 21 days. Fetal hemoglobin was measured in all patients; increased synthesis was found in 13 of the 17, in the absence of clinically significant anemia. Of the four patients who did not develop increased fetal hemoglobin, three had only one cycle of therapy. Fourteen patients with bronchogenic carcinoma were treated, and ten were evaluable for disease response. Five patients had disease stability of 2 or more mo, and five progressed on treatment. Three additional patients with mesothelioma were treated, and the two who were evaluable for disease response had stabilization of their disease. Fifteen of the 17 patients who received 5,6-dihydro-5-azacytidine developed a pleuritic-type chest pain, 12 had abnormal electrocardiograms, and four developed positive anti-nuclear antibodies. No significant hemopoietic, hepatic, or renal toxicities were observed. This study demonstrates that 5,6-dihydro-5-azacytidine in the dose and schedule used has no significant therapeutic activity in the treatment of lung cancer but does possess an unusual spectrum of clinical toxicities as well as the property of inducing fetal hemoglobin synthesis.

High-dose continuous infusion folinic acid and bolus 5-fluorouracil in patients with advanced colorectal cancer: a phase II study

Encouraging results have recently been reported for studies using folinic acid in combination with 5-fluorouracil (5-FU) in the treatment of patients with gastrointestinal (GI) malignancies. Thirty-six patients with advanced colorectal cancer with unequivocal evidence of progression while treated with fluoropyrimidines were treated with a six-day continuous infusion of 500 mg/m2/d of folinic acid initiated 24 hours before a five-day course of 5-FU administered as an intravenous (IV) bolus of 370 mg/m2/d. An initial dose of 250 mg/m2/d of 5-FU was used in patients previously treated with ionizing radiation and/or a nitrosourea. Three objective partial responses were observed. The overall median duration of survival was 8.1 months. Toxicity was acceptable and not in excess of that expected for 5-FU alone.