In vitro carboplatin-mesna interaction in aqueous solution, human plasma and urine

The chemotherapeutic benefit of synergistic drug combinations and higher drug dosages has generated interest in the application of these regimens to cancer patients. A major obstacle in the application of these strategies to the treatment of cancer is the dose-limiting toxicities of drug combinations. Sodium 2-mercaptoethane-sulfonate (mesna), a chemoprotective drug, may reduce the nephrotoxicity of carboplatin [CBDCA, paraplatin, JM-8, cis-diammine (1,1-cyclobutane dicarboxylato) platinum II] when administered in combination chemotherapy. The purpose of this study was to evaluate, compare and contrast in vitro the interaction of mesna with carboplatin in aqueous solution, human plasma and urine. Carboplatin and mesna were incubated separately and together at clinically relevant concentrations in plasma and urine. The concentration of carboplatin was assayed by HPLC, and the decay of carboplatin alone and in combination with mesna was compared. The incubation of carboplatin with mesna in human plasma up to 8 days did not result in a statistically significant interaction: the half-life of carboplatin in plasma when it was combined with mesna was 1.62 +/- 0.08 (SE) days compared to 1.85+/- 0.04 (SE) days for carboplatin by itself. The incubation of drugs in fresh human urine up to 15 days gave a half-life of 3.43+/- 0.8 (SE) days for carboplatin alone and 2.78 +/- 0.7 (SE) days for carboplatin when it was combined with mesna. Our results show that carboplatin and mesna do not significantly interact in plasma. Although a statistically significant difference between the half-life of carboplatin and the half-life of the carboplatin/mesna combination is detected in urine, it is not likely to be clinically significant, as there is no significant interaction detected in the first 48 h). It is thus unlikely that mesna would substantially affect the pharmacokinetics of carboplatin when both are given together to patients as part of combination chemotherapy regimens.

Preoperative radiation with concurrent 5-fluorouracil continuous infusion for locally advanced unresectable rectal cancer

BACKGROUND AND PURPOSE

To determine the percentage of complete responders and the resectability rate for patients with locally advanced carcinoma of the rectum treated by 5-fluorouracil (5-FU) infusional chemotherapy and pelvic radiation.

MATERIALS AND METHODS

Between October 1992 and June 1996, 29 patients with a diagnosis of locally advanced unresectable rectal cancer received preoperative 5 FU by continuous intravenous infusion at a dose of 225 mg/m2/day concurrent with pelvic radiation (median 54 Gy/28 fractions). All patients were clinical stage T4 on the bases of organ invasion or tumor fixation. Median time for surgical resection was 6 weeks.

RESULTS

Median follow-up for the group was 28 months (range 5-57 months). Six patients were felt to be persistently unresectable or developed distant metastases and did not undergo surgical resection. Of the 29 patients, 23 proceeded to surgery, 18 were resectable for cure, 13 by abdominoperineal resection, 3 by anterior resection and 2 by local excision. Of the 29 patients, 4 (13%) had a complete response, and 90% were clinically downstaged. Of the 18 resected patients, 1 has died of his disease, 17 are alive, and 15 disease-free. The regimen was well tolerated; there was only one treatment-related complication, a wound dehiscence.

CONCLUSION

The combination of 5 FU infusion and pelvic radiation in the management of locally advanced rectal cancer is well tolerated and provides a baseline for comparison purposes with future combinations of newer systemic agents and radiation.

Antisense nucleic acids targeted to the thymidylate synthase (TS) mRNA translation start site stimulate TS gene transcription

Thymidylate synthase (TS) is a key enzyme in the synthesis of DNA and a target for cancer chemotherapeutic agents. Antisense TS nucleic acids may be useful in enhancing anticancer drug effectiveness. MCF-7 and HeLa cells were transfected with vectors expressing antisense TS RNA or with antisense oligodeoxynucleotides (AS-ODNs) to different TS mRNA regions. Antisense RNAs were targeted to 30 bases of the TS mRNA including part of the stem loop at the translation start site and to 30 bases spanning the exon1/exon2 boundary. AS-ODNs were targeted to the translation start site and the translation stop site. Antisense nucleic acids complementary to the translation start site (and not the exon1/exon2 boundary or translation stop site) significantly enhanced constitutive TS gene transcription. Therefore, TS mRNA sequences appear to be involved in a novel pathway controlling TS gene transcription. Induced transcription could hinder antisense-based attempts to inhibit TS and must be considered when designing such strategies.

Superior vena cava obstruction in small-cell lung cancer

PURPOSE

To identify prognostic or treatment factors influencing the response of superior vena cava obstruction (SVCO), time to SVCO recurrence, and overall survival of SCLC patients with SVCO at presentation; and to assess the role of retreatment in patients with SVCO at recurrent or persistent disease.

METHODS AND MATERIALS

Between January 1983 and November 1993, 76 consecutive patients who had small-cell lung cancer (SCLC) with SVCO were treated in our institution. Analysis was done according to the disease status at diagnosis of SVCO. The first analysis concerned a group of 50 patients who had SVCO at initial presentation. The second analysis concerned a group who had SVCO as a manifestation of persistent or recurrent disease.

RESULTS

In the first analysis, 93% had significant improvement in symptoms of SVCO after chemotherapy and 94% after mediastinal radiation. Response is almost universal despite a wide range of radiation fractionation and total dose used. Seventy percent remained SVCO-free before death. Thirty percent developed recurrence of SVCO symptoms 1-16 months (median 8) after the start of initial treatment. Those who received combined chemotherapy and radiation had a longer time to SVCO recurrence (p = 0.018) compared to those who received chemotherapy alone. This effect is mainly seen in limited-stage patients. The presence of SVCO recurrence tends to have an adverse effect on the overall survival (p = 0.077) irrespective of the time when the recurrences occurred (p = 0.296). The median survival of this whole group of 50 patients in the first analysis was 9.5 months, and the 2-year survival was 10%. Stage was strongly predictive of survival (p < 0.001). Sixteen percent (3 of 19) of the patients with limited-stage diseases were long-term survivors (two patients survived 35 months and one survived 70 months). The early mortality from SVCO was 2%. In the second analysis, 85% had previously been treated with chemotherapy alone. The response rate of SVCO in the analysable patients (n = 39) was 77%. There was no significant difference in the response rate of SVCO to treatment comparing patients treated by chemotherapy first or mediastinal radiation first (p = 0.653), but most patients [82% (32 of 39)] received radiation as the initially treatment of SVCO. Ninety-three percent (38 of 41) received mediastinal radiation as a part of their ultimate retreatment regimen, and 68% (28 of 41) received mediastinal radiation as their sole retreatment regimen. Thirty-two percent (13 of 41) received chemotherapy as a part of their ultimate retreatment regimen, and only 7% received chemotherapy alone as their sole retreatment regimen. Eighty-three percent (25 of 30) of those whose SVCO responded remained free of SVCO before death, with a median survival of 3 months after recurrent or persistent disease documented.

CONCLUSION

Chemotherapy or mediastinal radiation is very effective as an initial treatment in SCLC patients with SVCO at presentation and at recurrent or persistent disease. There is no obvious need to use big radiation fraction sizes for the first few radiation treatment as was previously believed. In patients with recurrent or persistent SCLC with SVCO, especially in those who previously received chemotherapy only, we have more experience in incorporating mediastinal radiation as a major component of the palliative regimen with highly effective and durable palliation achieved.

Late intensification with high-dose melphalan and autologous bone marrow support in breast cancer patients responding to conventional chemotherapy

Fifteen patients with advanced breast cancer who had achieved either a good partial or a complete response to conventional chemotherapy were selected to receive intensification treatment with high-dose melphalan 140-200 mg/m2 (HDM). All patients received autologous bone marrow rescue. All patients experienced marked haematological toxicity, and most experienced moderate or mild gastrointestinal side effects. There were three treatment-related deaths. Of twelve assessable patients eleven have relapsed; median time to relapse after HDM is 7 months. Nine of these eleven have died from recurrent breast cancer. Of the three patients remaining alive, only one is disease-free, at 18 months after HDM. Analysis of the pattern of metastatic relapse suggests that recurrence was due to failure of HDM to eradicate residual disease in the patient, rather than reinfusion of viable tumour cells. Treatment intensification with HDM has not succeeded in prolonging survival in patients already in good remission.

Prognostic factors in small cell lung cancer: a simple prognostic index is better than conventional staging

Conventional staging in small cell lung cancer (SCLC) is only of limited prognostic value and is often based on elaborate investigations. We have carried out univariate and multivariate analysis of possible prognostic factors at presentation in 333 consecutive patients with SCLC. Fifteen parameters were found to have individual prognostic significance, of which the most powerful were serum albumin, bone marrow aspirate, disease extent and performance status (all P less than 0.00005). Factors which were not of prognostic significance included age, sex, SVC obstruction, and pleural involvement. Multivariate analysis excluded many factors including bone marrow aspirate as not being independently variable, and a simple combination of clinical performance status, serum albumin and alanine transaminase could be used to define 3 groups (good; medium; poor) of better prognostic significance (survival at 1 year 50% vs. 27% vs. 3%) than conventional limited/extensive disease staging (1 year survival 48% vs. 18%). Other simple combinations of biochemical parameters including plasma sodium and alkaline phosphatase achieved almost as good prognostic groupings. We suggest that consideration should be given to replacing the conventional limited/extensive disease staging system with a simpler system along the lines we have described.

The definition of a neoplasm

No satisfactory definition of a neoplasm exists. Current criteria are shown to be invalid for strictly definitional purposes. Difficulties relate in part to the difference between descriptions and explanations, and also to the status of definitional "truths". Definitions function to assist recognition, convey meaning and highlight the essence of what requires further explanation. Existing deficiencies and the provision of an adequate alternative are therefore matters of interdisciplinary importance with broad ramifications, particularly for the design of rational therapy. A new definition is proposed which, while saying as much as can be said, is conservative. Criticism of its logical base is anticipated and countered; two possible problems cases are admitted and discussed.

Carboplatin (Paraplatin; JM8) and etoposide (VP-16) as first-line combination therapy for small-cell lung cancer

Fifty-two previously untreated patients with small-cell lung carcinoma (SCLC) were treated with a combination of carboplatin 300 mg/m2 intravenously (IV) on day 1 and etoposide 100 mg/m2 IV on days 1 through 3 every 28 days for four courses. Patients with limited disease (LD) subsequently received thoracic radiotherapy; no prophylactic cranial radiotherapy was used. Forty-four patients (85%) achieved an objective response, including 82% (29% complete remissions) of LD patients and 88% (13% complete remissions) of extensive-disease (ED) patients. Median response duration for LD patients was 7 months and 5.5 months for ED patients. Median survival for both LD and ED patients was 9.5 months. Myelosuppression was the main toxicity, with World Health Organization (WHO) grade 3/4 leucopenia occurring in 44% of patients. There was one (2%) treatment-related neutropenic death. Treatment was otherwise well tolerated, and in particular no renal toxicity, neurotoxicity, or ototoxicity was seen. This new combination is highly active in terms of response rate, but response duration and survival is disappointing, and might be improved by prolonged treatment or by the use of additional drugs in combination.

Prolonged remission of severe refractory rheumatoid arthritis following allogeneic bone marrow transplantation for drug-induced aplastic anaemia

Aplastic anaemia developed in a 33-year-old woman whose rheumatoid arthritis was refractory to the administration of many drugs, including penicillamine and gold. Allogeneic bone marrow transplantation reversed the haematological abnormality and simultaneously resulted in a 2-year period of relief from joint pain. Symptoms then reappeared and the serological tests for rheumatoid arthritis again became positive. The arthralgia has responded slowly to the administration of anti-inflammatory drugs and steroids. The protracted asymptomatic period may have been due to the intense immunosuppression required for marrow grafting and the subsequent administration of cyclosporin. Since she developed chronic graft-versus-host disease, the arthritis may be an unusual complication of this syndrome.

An analysis of possible prognostic features of long term and short term survivors of metastatic breast cancer

Factors influencing the extremes of survival in disseminated breast cancer were analysed. From a pool of 1066 patients with distant metastatic breast cancer, the 41 patients who had survived 5 yr or more from first distant recurrence were matched with the 41 patients with the shortest survival times. Both groups were compared with the pool and, where relevant, with each other. There were no differences with respect to presentation clinical stage, histological subtype, adjuvant therapy or the likelihood of menopause during the disease-free interval. There were significant differences in age, menopausal status, primary treatment, grade, pathological node involvement, time to recurrence, situation and number of sites of metastatic involvement, and response to treatment. The interpretation of these relationships as causal or casual is uncertain; however, given the magnitude of the survival differences, we expected the associated differences to be much greater than we found.

The modulating effects of flurbiprofen on adriamycin plus vincristine or vindesine in the treatment of advanced breast cancer

To assess the modulating effects of a non-steroidal anti-inflammatory drug on chemotherapeutic agents, 183 patients with advanced breast cancer have been treated in a randomised study with flurbiprofen or placebo and adriamycin plus a vinca alkaloid. To assess the efficacy of the new vinca alkaloid, vindesine, in breast cancer, patients were further randomised to receive vindesine or vincristine. The overall response rate in evaluable patients was 57%, and the median duration of response in the different treatment groups varied from 6 to 10 months. Response rates and toxicity in vindesine- and vincristine-treated patients were similar, although with vindesine neurotoxicity was slightly lower. Flurbiprofen did not improve the response rate or reduce the toxicity of adriamycin plus vinca alkaloid.

Immunodepression, ascites tumour and lactate dehydrogenase virus

The delayed hypersensitivity (DH) response to picryl chloride was studied in Ehrlich ascites tumour-bearing and normal control mice. A significant depression of the DH response was found in the tumour-bearing mice, which was associated with a marked elevation of serum lactate dehydrogenase (LDH). Depression of DH was also observed in mice receiving cell-free ascitic fluid. These mice also showed an elevated serum LDH which is assumed to be associated with the lactate dehydrogenase virus. A method for assaying DH in vivo is described.