[Platinum salts: cytotoxic mechanisms of action, mechanisms of resistance of cancer cells, interactions with ionizing radiation, specificity of carboplatin]

Platinum compounds primarily act by damaging cellular targets inducing direct or indirect DNA alterations, and cytoplasmic proteins modifications. Molecular and cellular mechanisms of platinum resistance include increase of DNA repair, amplification of detoxifying proteins, modification of platinum transport, and alteration of oncogenes expression. This overview will describe those preclinical constatations related to cisplatin and will focus on carboplatin specificity.

Inhibition of glioma cells in vitro and in vivo using a recombinant adenoviral vector containing an astrocyte-specific promoter

Gene therapy using the herpes simplex virus thymidine kinase (HSV-TK) gene in combination with the drug ganciclovir (GCV) is a promising approach for the treatment of cancer-inducing gliomas, a tumor with a poor prognosis. In an attempt to limit the toxic effects on normal tissues, we constructed a recombinant adenoviral vector, Adgfa2TK, in which the HSV-TK gene is driven by the promoter for the gene encoding glial fibrillary acidic protein, an intermediate filament protein expressed primarily in astrocytes. Infection by Adgfa2TK of a glial cell line (C6) and a non-glial cell line (MDA-MB-231) revealed markedly increased expression of HSV-TK in glial cells as determined by Western blot. In comparison, high HSV-TK protein levels were produced in both cell lines after infection with a control virus, AdCMVTK, in which the constitutive cytomegalovirus viral promoter was used to direct HSV-TK expression. Infection of two glial cell lines (C6, U251) and two non-glial cell lines (HepG2, MDA-MB-231) with Adgfa2TK followed by GCV treatment revealed high toxicity in glial cell lines (50% growth inhibitory concentration: <2 microg/mL of GCV) with little or no toxicity (50% growth inhibitory concentration: >75 microg/mL) in the non-glial cell lines. In vivo, injection of Adgfa2TK into C6 tumors grown in nude mice followed by intraperitoneal GCV treatment significantly repressed tumor growth compared with the controls. Adgfa2TK may be useful for directing expression of the HSV-TK gene to gliomas.

Transactivation of the metallothionein promoter in cisplatin-resistant cancer cells: a specific gene therapy strategy

BACKGROUND

Cisplatin (cis-diamminedichloroplatinum) is one of the most active agents against a broad range of malignancies, including ovarian cancer. Cisplatin resistance appears to be associated with several molecular alterations, including overexpression of metallothionein, a metal-binding protein. In the present study, we attempted to take advantage of metallothionein overexpression to overcome cisplatin resistance.

METHODS

Using a virus-free system (liposomes), we sought to express the suicide gene, thymidine kinase (TK), driven by the promoter of the human metallothionein IIa (hMTIIa) gene using the pMT-TK plasmid. We used cisplatin-resistant human ovarian carcinoma cells as a model.

RESULTS

We first analyzed metallothionein expression using a ribonuclease protection assay. In comparison to parental cells, the cisplatin-resistant cells were found to have increased expression of metallothionein messenger RNA (mRNA). Metallothionein overexpression in these cells was not associated with an increased copy number of the hMTIIa gene or with different transfection efficiencies. Furthermore, we showed by reverse transcription-polymerase chain reaction analysis that transfection of the pMT-TK plasmid results in a 56-fold higher expression of thymidine kinase mRNA in cisplatin-resistant cells compared with parental cells, consistent with increased metallothionein promoter-mediated transactivation in the cisplatin-resistant cells. Transfection of resistant cells with pMT-TK or a control plasmid (pCD3-TK) resulted in a marked sensitization to ganciclovir, with a 50% cell growth-inhibitory concentration (IC(50)) of 20 microg/mL and 9 microg/mL, respectively. Transfections of the cisplatin-sensitive cells resulted in no sensitization to ganciclovir with pMT-TK (IC(50) 200 microg/mL) and a high sensitization with pCD3-TK (IC(50) = 6 microg/mL).

CONCLUSION

These studies suggest that pMT-TK gene therapy may provide an alternative treatment for cisplatin-refractory ovarian tumors.

A dose-finding study of gemcitabine and vinorelbine in advanced previously treated malignancies

PURPOSE

Gemcitabine and vinorelbine are active drugs with broad spectrum of activity and manageable toxicity in clinical trials. The aims of this study were to describe the toxicity, to determine the dose-limiting toxicity, and to define the doses of gemcitabine and vinorelbine to be recommended for phase II studies in patients with advanced cancers.

PATIENTS AND METHODS

Drugs were given as 30-min infusions on day 1 and 8 (vinorelbine before gemcitabine) every 3 weeks. Thirty-six patients (male:female ratio 25:11; mean age 54, PS > 60) were treated including 1 retroperitoneal sarcoma, 7 head and neck, 10 lung, 4 thyroid, 6 pancreatic, 1 bladder, 2 ovary, 2 gastric, 1 rectum, 1 unknown primary, and 1 renal cell carcinoma. Doses of gemcitabine/vinorelbine ranged from 800/20 mg/m2 to 1500/30 mg/m2.

RESULTS

The dose-limiting toxicity was neutropenia. A transient grade 2-3 elevation of transaminases was frequently observed at several dose-levels, although this toxicity did not appear to be dose dependant and was reversible at day 21 before the next cycle. Other toxicities were mild and easily manageable, consisting of fatigue and flu-like syndromes. Since the MTD was not reach at the higher dose-level, the recommended dose level of the gemcitabine-vinorelbine combination was 1500/30 mg/m2. One toxic death due to hematologic toxicity was reported in a heavily pretreated patient who underwent prior chemotherapy and pelvic radiotherapy. A total of 12 patients were treated at the recommended dose level which was associated with grade 3-4 neutropenia in 3 of 12 patients and in 22.9% of cycles.

CONCLUSIONS

This study estimates that the recommended dose for phase II studies of gemcitabine-vinorelbine is 1500/30 mg/m2 at day 1 and 8 every three weeks. A careful monitoring of the hematologic toxicity is recommended in heavily pretreated patients and in patients who received pelvic radiotherapy. Partial responses observed in a patient with an advanced cisplatin-5-fluorouracil-resistant pancreatic adenocarcinoma and in a patient with mesothelioma support further evaluation of this combination in patients with tumors refractory to classical antitumor agents.

Docetaxel-cisplatin combination (DC) chemotherapy in patients with anthracycline-resistant advanced breast cancer

PURPOSE

The safety and efficacy of a docetaxel-cisplatin combination (DC) were evaluated in 41 patients pretreated for advanced breast cancer (ABC).

PATIENTS AND METHODS

The first 2 patients received 85 mg/m2 docetaxel followed, 6 hours later, by 80 mg/m2 cisplatin repeated every 3 weeks; the other 39 received the same regimen, with 75 mg/m2 docetaxel. Appropriate dose reductions but no growth factor administration were planned. Treatment was continued until disease progression, excessive toxicity or patient refusal.

RESULTS

A total of 223 chemotherapy courses were administered, with a median of 6 cycles per patient (range 1-8). All 41 patients were assessed for toxicity using NCI-CTC. Severe neutropenia was experienced by 38 patients (93%) (11 at grade 3, 27 at grade 4, 10 with febrile neutropenia). There was one death due to neutropenic septic shock. Grade 3 thrombocytopenia occurred in three patients (7%). Five patients (12%) had grade 2 neurosensory toxicity, two (5%) experiencing partial hearing loss. Grade 3 fluid retention occurred in three patients (7%). Of 38 anthracycline-resistant patients, 33 were evaluable for response. Two had a complete response (CR) and ten a partial response (PR), giving an objective response rate of 36%, (95% CI: 20%-55%). Stable disease (SD) was observed in 14 patients (42%), 7 (21%) had progressive disease (PD). Among the three non-resistant patients, two PRs and one SD were observed. Median duration of response was 29 weeks (range 18-70), median time to progression 21 weeks (4-70), and median overall survival 50 weeks (4-104+).

CONCLUSIONS

This DC regimen is active, with an acceptable safety profile in anthracycline-resistant ABC patients. Its place as a second-line treatment alternative to docetaxel alone or to other second-line combination regimens remains to be determined.

Selective killing of glioma cell lines using an astrocyte-specific expression of the herpes simplex virus-thymidine kinase gene

Gene therapy using the herpes simplex virus thymidine kinase gene (HSV-TK) is a promising new approach for the treatment of gliomas, a tumor type with a poor prognosis. To limit the toxic effects of this procedure, it is desirable to restrict expression of the HSV-TK gene to the target cells. This can be accomplished by use of the promoter of the glial fibrillary acidic protein gene, an intermediate filament protein expressed primarily in astrocytes. A plasmid containing the HSV-TK gene, driven by the human glial fibrillary acidic protein promoter gfa2, was lipofected into glioma cell lines and into an ovarian cancer cell line. Treatment with ganciclovir showed efficient killing of glioma cells, with no effect on the ovarian cells. Thus, the gfa2 promoter is a promising candidate for directing expression of toxic genes to gliomas.

Normal serum neuron specific enolase (NSE) value after the first cycle of chemotherapy: an early predictor of complete response and survival in patients with small cell lung carcinoma

BACKGROUND

Serum neuron specific enolase (NSE) is the most sensitive tumor marker of small cell lung carcinoma (SCLC) at diagnosis. Its prognostic value is still debated. Thus, the authors decided to assess the predictive value, in terms of complete response and survival, of serum NSE measured before and after one cycle of chemotherapy in patients with SCLC.

METHODS

Sera from 135 patients with histologically proven limited (n = 63) or metastatic (n = 72) SCLC were obtained. Clinical and biologic parameters with a known or suspected prognostic relevance were reviewed. Serum NSE was measured before chemotherapy (D1-NSE) and 28 days after its initiation (D28-NSE). The prognostic value of the parameters under study was evaluated in univariate and multivariate analyses using the Cox proportional hazards model and logistic regression analysis.

RESULTS

The level of serum NSE was raised in 120 patients (88%) prior to therapy. The probability of a normal D28-NSE value was not affected by the baseline D1-NSE value. Disease extension (P = 0.0005), performance status (P = 0.0001), D28-NSE (P = 0.003), and carcinoembryonic antigen (CEA) levels (P = 0.008) were found to be predictive for survival, whereas age, gender, plasma sodium, serum protides, and D1-NSE were not. Median survival and 2-year overall survival were 15.3 months and 21% (95% confidence interval [CI], 13-31%) when D28-NSE was normal and 8.1 months and 15% (95% CI, 8-27%) when it was not (P < 0.03). Only performance status (P = 0.001), disease extension (P = 0.002), and D28-NSE (P = 0.02) were found to be independent prognostic parameters for survival in the multivariate analysis. A simple prognostic index was developed using these 3 variables. Limited disease, a normal D28-NSE value, and a normal CEA value prior to therapy were the only parameters predictive for complete response in the univariate analysis, and D28-NSE (P = 0.01) and disease extension (P = 0.0001) were found to be independent variables in multivariate analysis. A complete response to therapy occurred in 62% with a normal D28-NSE value and in only 34% in the opposite case.

CONCLUSIONS

Normal serum D28-NSE is a strong, independent early predictor of both complete response to therapy and survival. This simple tool may be proposed for use in the clinic and in research, in association with an assessment of disease extension and performance status, to predict the outcome of patients with SCLC.

Initial management of primary mediastinal seminoma: radiotherapy or cisplatin-based chemotherapy?

Primary mediastinal seminoma is an uncommon neoplasm, the optimal management of which is still debated. Radiotherapy produces a 65% disease-free survival rate. We assess whether these results have been improved with the advent of cisplatin-based chemotherapy. Data from 14 patients treated at the Institut Gustave-Roussy were reviewed. 9 had received cisplatin-based chemotherapy (Group 1): their outcome was compared with that of 5 patients treated with radiotherapy without chemotherapy (Group 2). We also reviewed data from the English literature using strict criteria, and report results concerning patients who received cisplatin-based chemotherapy and those who received radiotherapy. 8 of the 9 patients (89%) in Group 1 are long-term disease-free survivors and only 3 of 5 patients in Group 2. The patient who died in Group 1 was the only one who refused surgical resection of residual masses after chemotherapy. The review of the literature revealed that 59 of 68 (87%) patients initially managed with cisplatin- or carboplatin-based chemotherapy and for whom sufficient data are available, are long-term survivors and free of disease. Some of these patients had also received radiotherapy. Only 64 of 103 (62%) treated with thoracic radiotherapy without chemotherapy were long-term disease-free survivors. The disease-free survival rate of 51 patients who received cisplatin-based chemotherapy (excluding those who received carboplatin) was 86%. The difference in survival between patients administered cisplatin-based chemotherapy and those who underwent radiotherapy is apparently not due to unbalanced prognostic factors, the effect of time or non-specific medical management. We conclude that cisplatin-based chemotherapy allows long-term disease-free survival in approximately 85% of patients. These results seem to be higher than those obtained without cisplatin-based chemotherapy. However, a randomised study is required for definitive conclusions, but it is very unlikely that such a study will be performed due to the rarity of this neoplasm. Another alternative would be a meta-analysis based on individual data.

Review article: Overview of medical treatments in unresectable hepatocellular carcinoma--an impossible meta-analysis?

BACKGROUND

Controversies surrounding medical treatment in patients with unresectable hepatocellular carcinoma continue to persist.

AIM

To perform a meta-analysis of therapeutic modalities which had been evaluated in two or more randomized trials.

METHODS

Fifty-two randomized trials were studied; only 30 were included. This overview identified seven therapeutic modalities which had been evaluated in two or more trials: adriamycin, 5-fluorouracil, interferon, percutaneous ethanol injection, transarterial chemotherapy, the combination of lipiodol with transarterial chemotherapy, and tamoxifen.

RESULTS

Comparisons of survival between control groups showed substantial heterogeneity. There was no survival benefit at 1 year with adriamycin (mean difference 4%), 5-fluorouracil (mean difference -3%), percutaneous ethanol injection (mean difference 6%) or transarterial chemotherapy (mean difference -2%). For interferon, the survival benefit was significant with the Der Simonian & Laird method (mean difference 9%, 95% CI = 1-18%, P = 0.04) but not with the Peto et al. method (2.4 mean odds ratio, 95% CI = 0.9-6.8). The meta-analysis of tamoxifen showed a borderline survival benefit (mean difference 25%, 95% CI = 0-49%, P = 0.05). However, in sensitivity analyses, the survival benefit of tamoxifen was no longer significant.

CONCLUSIONS

No treatment has clearly proven efficacy in survival. 5-Fluorouracil, adriamycin and transarterial chemotherapy were not associated with survival benefit at 1 year. The number of randomized controlled trials was insufficient to enable a conclusion to be reached for interferon and percutaneous ethanol injection. Controversy persists concerning tamoxifen efficacy. Interferon and tamoxifen require new randomized controlled trials on a larger population of patients.

[Telomeres, telomerase and cancer]

The chromosome ends are specialized nucleoprotein structures called telomeres, which length predicts replicative capacity of cells. Activation of telomerase, the DNA polymerase that synthesizes telomeric repeats, seems to be necessary for cells to become immortal. Methods of measuring telomerase activity, now reliable and semiquantitative, have shown that telomerase is expressed in most human cancers, but not in normal somatic tissues. Research about regulation of telomere length and telomerase activity, highlights connexions between senescence and cancer. This article details diagnosis, prognosis and therapeutic prospects linked to the study of telomerase activity.

A phase II study of cisplatin, 5-fluorouracil, leucovorin, and etoposide in advanced non-small-cell lung cancer

The aim of this study was to define the efficacy of a combination of cisplatin, 5-fluorouracil (5-FU), leucovorin, and etoposide (VP-16) in locally advanced or metastatic non-small-cell lung cancer (NSCLC). From September 1991 to November 1994, 28 patients were treated with cisplatin, 100 mg/m2 i.v. on day 1; 5-FU and leucovorin, 500 mg/m2 on days 1, 2, 3, and 4 by i.v. continuous infusion; and VP-16, 70 mg/m2 i.v. on days 1, 2, 3, and 4 (combination, PFL-VP-16). Cycles were repeated every 3 weeks. There were 22 men and six women. The median age was 58 (range, 41-76). All had measurable diseases (one was stage IIIA, six were IIIB, and 21 were IV). None had previously received chemotherapy for metastatic disease. There was one complete response and six partial responses, for an overall response rate of 25% (95% confidence interval 9-41%). The median response duration and the overall survival were 8 and 9 months, respectively. Limiting toxicity was myelosuppression and oral mucositis. Grade 3 or 4 leucopenia was observed in 20% of all of the 95 cycles administered, and oral mucositis in 13%. No grade 3 or 4 renal toxicity occurred, and neurologic toxicities were limited (3% of the 28 patients experienced grade 3). PFL-VP-16 is active and can easily be administered to patients with advanced NSCLC. However, according to the results obtained with this schedule, VP-16 does not increase either response rate or survival compared with the regimen previously described by Vokes et al. (PFL).

Preliminary results of a phase I/II study of paclitaxel, cisplatin, and cyclophosphamide in advanced ovarian carcinoma

The clinical activity and toxicity of the triple combination of paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ), cyclophosphamide, and cisplatin was assessed in both previously treated and untreated women with advanced ovarian carcinoma. Paclitaxel 175 mg/m2 was administered over 3 hours following standard premedication (prednisolone, dexchlorpheniramine, and cimetidine). Cisplatin 80 mg/m2 and cyclophosphamide 600 mg/m2 were given 6 to 12 hours after paclitaxel. Treatment was given at 3-week intervals for six cycles. Twenty-seven patients entered the study; 23 were evaluable for toxicity and 17 for response. Paclitaxel appeared to add additional efficacy to the standard cisplatin/cyclophosphamide regimen. Both the overall and complete remission rates were very high (88% and 70%, respectively), and histologically confirmed complete remissions exceeded 60%. Longer follow-up is needed to determine the duration of these responses. The primary toxicities included leukoneutropenia, peripheral neuropathy, asthenia, and alopecia. Only two of 23 patients withdrew because of toxicity, however, and only two treatment cycles were complicated by neutropenic fever requiring intravenous antibiotics. No life-threatening toxicities were encountered, although the peripheral neuropathy was poorly and slowly reversible and may have a significant impact on the patients' quality of life.

Ca125 and neuron-specific enolase (NSE) as tumour markers for intra-abdominal desmoplastic small round-cell tumours

Seven consecutive patients with intra-abdominal desmoplastic small round-cell tumours were screened at presentation for carcinoembryonic antigen (CEA), Ca19-9, Ca15-3, Ca125, alpha-fetoprotein (AFP), human chorionic gonadotrophin (hCG) and neuron-specific enolase (NSE). Initially elevated tumour markers were used to monitor therapy and follow-up. Tumour marker assays were all in the normal range, with the exception of Ca125 and NSE. The Ca125 level was initially high in six of the seven patients (86%) with a median value of 200 U ml-1 and a range of 22-735 U ml-1. The NSE value was elevated before therapy in three of the five patients (60%) for whom assay results were available, with a median of 19 ng ml-1 and a range of 6.8-37.5 ng ml-1 . Ca1 25 normalized in five out of six cases and NSE always normalized during chemotherapy, but neither of these two tumour markers correlated specifically with response, as only one patient experienced a partial response, five tumour stabilization and the remaining patient tumour progression. At progression, Ca125 was again elevated in two out of four cases several weeks before clinical relapse and NSE in only one out of three cases. Ca125 and NSE are frequently raised in the serum of patients with intra-abdominal desmoplastic small round-cell tumours before therapy, but are not reliable monitors of the course of the disease. However, normalization is frequently associated with an improvement of symptoms or a moderate clinical response.

Oxaliplatin, tetraplatin, cisplatin, and carboplatin: spectrum of activity in drug-resistant cell lines and in the cell lines of the National Cancer Institute's Anticancer Drug Screen panel

The present study was designed to explore the activity of platinum compounds in cisplatin-resistant cell lines, the unselected cell lines of the National Cancer Institute's Anticancer Drug Screen, and the potential for use in combination. The activities of four platinum compounds in cisplatin-resistant KB and A2780 cells were investigated. The cells were highly resistant to cisplatin and cross-resistant to carboplatin, but less than one-tenth as resistant to oxaliplatin and tetraplatin. Cellular accumulation of all platinum compounds was decreased in both resistant cell lines. When the activities of cisplatin and oxaliplatin were evaluated in the National Cancer Institute's Anticancer Drug Screen, marked differences were observed. Evaluation of the activity profile using the COMPARE program revealed a different pattern for both agents: the cisplatin activity profile was similar to those of other diamine-platinum compounds, alkylating agents including melphalan, and camptothecin analogs, whereas the activity profile of oxaliplatin resembled those of other "dach" (diaminocyclohexane) platinum compounds and of acridine derivatives. The sensitivity profiles are influenced by the target(s)/mechanism(s) of action and the mechanism(s) of resistance of a drug. The dissimilarity in profiles suggests that these two platinum compounds have a different target(s)/mechanism(s) of action, a different mechanism(s) of resistance, or most likely both. Studies evaluating combinations of cisplatin/oxaliplatin suggest that the activities of these two agents are at least additive and possibly synergistic. Oxaliplatin has a different spectrum of activity and low cross-resistance to cisplatin and should be valuable in cisplatin refractory patients or in combination with cisplatin.

CPT-11. The European experience

CPT-11 is a derivative of camptothecin, which has a broad spectrum of antitumor activity, both in vitro and in vivo. Like camptothecin, CPT-11 is a selective inhibitor of the DNA enzyme topoisomerase I. Phase I trials were conducted in Europe with the aim of determining the recommended CPT-11 dose and schedule for evaluation in phase II trials. The phase I trials assessed the toxicity of CPT-11 in 235 patients and tested three different administration schedules. CPT-11 was administered as a single infusion once every three weeks, as a weekly infusion for three weeks out of every four, and as a daily infusion for three consecutive days every three weeks. The maximum tolerated dose (MTD) was 115 mg/m2 in the daily schedule and 145 mg/m2 in the weekly schedule. When the drug was administered once every three weeks, diarrhea became the dose-limiting toxicity at doses above 350 mg/m2. This schedule allowed the highest dose intensity to be obtained, was the best tolerated, and allowed ambulant treatment. Finally, using this schedule, a combination of CPT-11 with high doses of loperamide allowed the dose of CPT-11 to be increased to 750 mg/m2. An ongoing phase I trial is investigating the combination of CPT-11 and 5-fluorouracil (5-FU) in various solid tumors. Although the MTD has not yet been reached, preliminary results have not demonstrated any pharmacokinetic interaction between the two drugs, contrary to the findings of a previous Japanese study. Based on the results of the three phase I trials, CPT-11 administered at a dose of 350 mg/m2 as an intravenous infusion over 30 minutes once every three weeks has been recommended for assessment in phase II trials. The phase II trials started in Europe at the beginning of 1992. To date, CPT-11 has showed remarkable efficacy in colorectal cancer, even in patients resistant to 5-FU. Interesting results have also been obtained in pancreatic, cervical and lung cancer. Future trials will make it possible to assess whether there is a place for CPT-11 in combination with other cytotoxic agents or radiotherapy.

Phase I/II study of paclitaxel, cisplatin, and cyclophosphamide in advanced ovarian carcinoma: preliminary results

In this phase I/II study, we assessed the impact of paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) in the treatment of advanced ovarian carcinoma combined with the standard regimen cisplatin/cyclophosphamide given as follows: paclitaxel 175 mg/m2 (over 3 hours perfusion with standard premedication), cisplatin 80 mg/m2 (6 to 12 hours after paclitaxel), and cyclophosphamide 400 mg/m2. From February 1994 to January 1996, 27 patients (median age, 55 years; age range, 35 to 74 years) were entered into the study. Eight patients had distant metastases and 19 had early locoregional disease (stage III, 18 patients; stage IC, one patient). Twenty-two patients had undergone prior surgery (simple biopsy, six patients; optimally debulked, nine patients; suboptimally debulked, seven patients). Twenty-one patients had received no prior chemotherapy and six were previously treated with at least one platinum-based regimen. A maximum of six courses of paclitaxel/cisplatin/cyclophosphamide were given every 21 days. Twenty-three patients were evaluable for toxicity: neutropenia (World Health Organization grade 3/4), 91% of patients; thrombopenia (World Health Organization grade 3/4), 13% of patients; two episodes of neutropenia with fever; and neurotoxicity grade 3, 17% of patients. Alopecia grade 3 was reported in all patients. No hypersensitivity reactions and no cardiac toxicity was observed. Among 17 patients evaluable for response (patients with stage IV disease or stage III suboptimally debulked), 12 (70%) clinical complete responses (CRs) and three (18%) partial responses were observed. Among the 12 patients with CRs, 10 underwent second-look laparotomy and seven of them (70%) achieved a pathologic CR. In the group of 11 chemotherapy-naive patients evaluable for response, eight (72%) achieved a CR and three (28%) achieved a partial response. This combination seems to be safe, with very acceptable toxicity, and also seems to be highly active in the treatment of patients with advanced ovarian carcinoma.

[Resistance to anticancer drugs]

Due to inefficacy of chemotherapy in several cancers, chemoresistance mechanisms which are intrinsic to tumor cells have been extensively described in human cancer cell lines. Detoxifying mechanisms including active efflux pumps (P-gp, MRP or LRP) and/or drug inactivation (glutathione) as well as increased DNA repair have been identified and demonstrated to be involved in chemoresistance processes. Moreover expression of genes implicated in proliferation, differentiation or apoptosis functions has been shown to indicate drug response. Several mechanisms very often coexist within the tumor cell: it is possible even that detoxifying mechanisms are dependent on oncogenes and suppressor genes regulating proliferation, differentiation and/or apoptosis. In human tumor specimens, some of these mechanisms are regularly found and thus lead to develop strategies to block them. In that respect, the first example is the development of modulators of P-gP, a membrane efflux protein, which constitutes the archetype of detoxifying drug mechanisms. In spite of technical difficulties encountered to properly identify and quantify expressions of these biomarkers, ongoing research in cancer chemotherapy now largely relies on chemoresistance mechanisms.

Liposomal delivery of the herpes simplex virus thymidine kinase gene in glioma: improvement of cell sensitization to ganciclovir

In this study, we investigated whether the regulation and the copy number of the herpes simplex virus thymidine kinase (HSVtk) gene increased the sensitization to ganciclovir (GCV) of glioma cell lines (Rat C6 and human U118-MG) using liposome-mediated gene transfer. Three recombinant plasmids carrying the HSVtk gene driven by the thymidine kinase promoter in single (pAGo) and double copy (pYED) or by the human cytomegalovirus promoter (pCMVtk) were used for the transfection. The DNA delivery was optimized by screening a panel of cationic liposomes using Lac-Z and luciferase as reporter genes. The efficiency of transfection reached 33% to 36% in vitro but only 18.6% in vivo after an intratumoral injection of DNA-liposome complexes. Moreover, after transfection of the three plasmids, the cell-killing effect of GCV was evaluated. A significant enhancement (four- to fivefold) of the cell sensitivity to GCV was shown in pCMVtk and pYED as compared with pAGo-transfected cells in both cell lines. According to the plasmid, the effect of the HSVtk/GCV system was confirmed by in vivo experiments and was objectified by a higher tumor weight reduction with pCMVtk (49%) than pAGo (27%). From these results, we conclude that (1) the gene transfer can be achieved by cationic liposomes both in vitro and in vivo and that (2) using this type of vector, the antitumor effect of the HSVtk/GCV system could be potentiated by the up-regulation of HSVtk gene duplication.

In vitro sensitization of the B16 murine melanoma cells to ganciclovir by different RNA and plasmid DNA constructions encoding HSVtk

The antiviral drug ganciclovir (GCV) is toxic for mammalian cells transfected with the herpes simplex virus thymidine kinase (HSVtk) gene. To improve the results obtained by our group previously on nonviral transfection of tumor cells, we have examined here in vitro virus-free transfection of murine B16 melanoma cells via lipofectamine-nucleic acid complexes carrying either HSVtk gene transcripts or plasmid DNAs containing single and double copies of the HSVtk gene. The HSVtk gene transcripts as well as plasmids containing the HSVtk gene(s) rendered cells sensitive to GCV treatment. Tumor sensitivity to GCV conferred by the HSVtk gene transcripts was of the same level as the sensitivity conferred by plasmid DNAs containing a single copy of the HSVtk gene. However, when the plasmids containing double copies of the HSVtk gene were used, sensitivity to low GCV concentrations increased dramatically. One could appreciate this finding as an essential advantage of the plasmids containing double copies of the HSVtk gene since it allows use of the GCV concentration range which is common in clinical applications.

Endogenous interleukin 6 levels in patients with metastatic malignant melanoma: correlation with tumor burden

The involvement of interleukin (IL-) 6 in malignant disease has been investigated in a variety of different malignancies. To evaluate whether serum IL-6 is a useful disease marker in metastatic malignant melanoma (MMM), we studied the time course of endogenous IL-6 secretion in 41 patients treated with cisplatinum, IL-2, and IFN-alpha. Furthermore, the relationship of endogenous IL-6 concentrations to the tumor burden and/or the clinical response was also evaluated. The baseline serum IL-6 levels were significantly higher in patients with MMM than in the control group (P = 0.002). When tumor burden was taken into consideration, we found that IL-6 levels were higher in patients with high tumor burden than in patients with low tumor burden. During treatment in the whole patient population, a higher serum IL-6 level was observed in nonresponding as compared to responding patients at days 7 (P = 0.0005), 21 (P = 0.002), and 35 (P = 0.009). The follow-up of serum IL-6 in patients with MMM according to the tumor burden and clinical response demonstrated that: (a) IL-6 levels were significantly higher at days 7 and 21 in patients with high tumor burden as compared to those with low tumor burden; and (b) IL-6 levels remain significantly higher in nonresponding patients as compared to responding patients regardless of the tumor burden. From these results, we can conclude that endogenous IL-6 may play a role in the failure of IL-2 therapy in such patients, since the very early IL-6 increase is correlated with the tumor mass and nonresponse to biochemotherapy. Therefore, it seems that the early detection of endogenous IL-6 may represent valuable information for monitoring the response to biochemotherapy in patients with MMM.

Gene transfer in hepatocarcinoma cell lines: in vitro optimization of a virus-free system

Many approaches exist for hepatic gene delivery, including viral vectors and non-viral vectors. In this study, we tested a panel of liposomes to transfer pAGO, a plasmid containing one copy of herpes simplex virus (HSVtk) gene, and pYED11, a plasmid containing two copies of the HSVtk gene, into a murine hepatocarcinoma cell line (Hepa 1-6) and a human hepatocarcinoma cell line (Hep-G2). The efficiency of gene delivery and expression was characterized by beta-galactosidase staining, flow cytometric analysis and quantitative lacZ activity. Different combinations of liposomes and DNA and the ratio of the concentration of liposome to DNA were tested. The efficient transfer was shown with DOTAP followed by transfectam and lipofectamine. Under these conditions, we tested the cytotoxicity of ganciclovir (GCV) exposure on Hepa 1-6 and Hep-G2 transfected separately with liposome-pAGO and liposome-pYED11 complexes. This study demonstrates the in vitro efficacy of each liposome tested to transduce the HSVtk gene into hepatocarcinoma cell lines. The transfer of two copies of the HSVtk gene rendered cells 1.5 times more sensitive to GCV than cells transduced by pAGO as compared to controls. This was achieved most efficiently by the DOTAP-pYED11 complex. Thus, pYED11 may be considered as an alternative to pAGO as a gene transfer vector.

Direct gene transfer of a plasmid carrying the herpes simplex virus-thymidine kinase gene (HSV-TK) in transplanted murine melanoma: in vivo study

The aim of the study was to use a virus-free system to transfer the Herpes Simplex Virus-thymidine kinase (HSV-TK) gene in mice bearing melanoma tumours. B16 F1 murine melanoma cells were injected subcutaneously. On days 11 and 14, an intratumoral injection of either naked plasmid containing the HSV-TK gene (pAG0) or pAG0-lipofectamine complexes was given. Ganciclovir (120 mg/kg/day) was given for 5 days starting on day 14. Tumour weight reduction (40-50%) was observed in treated animals versus different control groups. Moreover, histopathological analysis on tumours showed large areas of cavitary necrosis (85%) in treated groups compared to controls (10%). Using a simple and safe method, the results presented here demonstrated that virus-free mediated delivery of the HSV-TK gene is efficient in vivo in murine malignant melanoma.

Complete remission seven years after treatment for metastatic malignant melanoma

BACKGROUND

In this study, the authors identified seven-year survivors after completion of the French multicenter Phase II trial of fotemustine for the treatment of metastatic malignant melanoma.

METHODS

One hundred sixty-nine patients with metastatic malignant melanoma were included in this Phase II study. One hundred fifty-three patient records were evaluable with an overall response rate of 24.2%.

RESULTS

Five of these patients are alive and in complete remission. One patient had a complete response after fotemustine administration and then relapsed. One patient had a partial response. Three patients had stable disease. These five patients underwent surgery for relapse or residual disease and subsequently achieved durable complete remission.

CONCLUSIONS

Long term survival may be the outcome after surgical resection of residual metastatic melanoma after chemotherapy.

Virus-free transfer of the herpes simplex virus thymidine kinase gene followed by ganciclovir treatment induces tumor cell death

We report virus-free transfer of a "suicide" gene into tumoral cells. The system can be used in vitro or in vivo to induce tumor cell death. A plasmid carrying the herpes simplex virus thymidine kinase (HSV-TK) gene with its 5'- and 3'-flanking regions was used both alone and in liposomes to transduce B16 cells. In vitro, a 5-day treatment with ganciclovir after transfection with the HSV-TK gene in liposomes induced a significant lysis of B16 melanoma cells as assessed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide test. The efficacy of transfection was determined using liposomes harboring the beta-galactosidase reporter gene and was around 10%. Thus, the cytotoxicity observed resulted presumably from a large bystander effect. In vivo, direct transfer of the TK DNA into established B16 melanoma tumors in C57B6 mice followed by i.p. ganciclovir treatment induced a 50% reduction of tumor weight after 8 days and an increased necrosis. Despite the use of the nonspecific strong TK promoter, no necrosis was detected in normal tissues surrounding the tumor or elsewhere. Thus, this system of tumor transfection, which does not involve any viral vector, is safe and straightforward and seems to be suitable for testing in clinical trials.

Fotemustine, dacarbazine, vindesine combination chemotherapy in advanced malignant melanoma: a phase II study of 43 patients

Fotemustine and dacarbazine constitute the most active single chemotherapeutic agents in the treatment of melanoma. In this phase II study we evaluated the activity and toxicity of a combination of fotemustine, dacarbazine and vindesine as a means of increasing response rate and survival time. Between September 1989 and November 1993, 43 patients with advanced melanoma were treated with a combination of 100 mg/m2 fotemustine on days 1 and 8, 250 mg/m2 dacarbazine on days 15 and 16 and 2 mg/m2 vindesine on days 15 and 16 as induction treatment. After a 5-week rest period, the patients exhibiting a response or stable disease received the same drugs administered once every 28 days as maintenance therapy until either progression or toxicity was observed. Among 41 evaluable patients, there were six complete responses and eight partial responses. The overall response rate was 32% (95% confidence interval: 18-46%), with 8 months median duration of response. Median survival time was 10 months. This regimen was well tolerated. From this large phase II study, we conclude that such a combination is active against advanced malignant melanoma and seems to be more effective than fotemustine or dacarbazine used alone, especially on visceral metastatic sites.

A phase II study of tamoxifen combined with cisplatin-interleukin 2 and alpha-interferon in metastatic melanoma

Tamoxifen (TAM) has been reported to enhance cisplatin (CDDP) cytotoxicity in experimental and clinical melanoma studies. Based on our previous experience with sequential cisplatin-interleukin-2 (IL2)-interferon (IFN), we performed a phase II study of TAM combined with our original CDDP-IL2-IFN regimen in 22 pretreated metastatic melanoma patients. With a 41% response rate (95% CI, 21-61) we confirmed the interesting antitumor activity of CDDP-IL2-IFN combination; however, TAM enhanced neither the response rate nor the duration of response, but appeared to induce significantly more myelotoxicity, as compared to our previous results with CDDP-IL2-IFN alone. Whereas mechanisms by which TAM may modulate CDDP cytotoxicity in melanoma tumors remain unknown, the exact place of TAM, if any, and its safety in chemotherapeutic or chemoimmunotherapeutic combinations require further investigations.

[Breast cancer: role of MRI in follow-up of cases treated]

Conventional imaging (CI) for breast cancer includes mammography and ultrasound. Its limited efficiency is especially manifest for breast cancer follow-up after breast-conserving therapy (i.e. exclusive radiation therapy) and after breast implant. Lack of evidence for definitive diagnosis increases the number of invasive explorations. To improve the specificity of the diagnosis between recurrence or fibrosis, we describe the interest of new imaging (NI) techniques: post-contrast MRI, and MR angiography (MRA), realized in 1 exam. Between October 1993 and December 1994, 82 patients were eligible for these investigations. All patients had an history of conservative breast cancer treatment of breast implant following mastectomy. In all cases CI was not contributive for a precise diagnosis; therefore a biopsy was performed and confirmed the diagnosis of breast cancer. NI was done before biopsy and compared results are following. 19 more patients were evaluated for primary chemotherapeutic response, including a total of 101 patients. Regarding the follow-up of prosthesis and conservative treatment, the correlation with histological control was obtained in 95% with four false diagnoses due to confusion between retroprosthesis relapse and inflammation. Historadiologic correlation were close to 90% for the evaluation of primary chemotherapeutic response. Studies are ongoing to confirm those preliminary findings. Though expansive, these techniques might be cost-effective if they result in a substantial decrease of unnecessary surgical invasive procedures.

Study of IL-2 receptor expression after chemoimmunotherapy in patients treated for metastatic malignant melanoma

Using flow cytometry, cellular IL-2 receptors were studied before and following chemoimmunotherapy combination in 20 patients with metastatic malignant melanoma (MMM). Patients received cisplatin (100 mg/m2) at days 1 and 28, recombinant IL-2 by continuous infusion from days 3 to 6, 17 to 21, 31 to 34, and 45 to 49. Interferon-alpha (IFN-alpha) was given subcutaneously three times weekly. In terms of clinical response, we observed 55% objective response (complete: 15%). When pretreatment blood samples were compared with those of healthy donors, we did not observe any change in low (alpha chain) and high affinity receptor (alpha + beta) expression. In contrast, intermediate affinity p75 (beta chain) expression was decreased significantly (P < or = 0.0001) in MMM patients. During treatment, we found a dramatic increase of beta chain as well as high affinity (alpha + beta) expression in responding patients, as soon as IL-2 therapy began. Furthermore, the increase of beta chain expression was limited to natural killer (NK) cells (CD56+). In non-responding patients, on the other hand, increase of both receptors was seen only at day 31. These data suggest the involvement of beta chain expression in the mechanism of cell activation after chemoimmunotherapy. Moreover, this early beta chain expression is correlated with the clinical response to chemoimmunotherapy.

Sequential chemoimmunotherapy with cisplatin, interleukin-2, and interferon alfa-2a for metastatic melanoma

PURPOSE

To evaluate the activity and the toxicity of the combination of cisplatin (CDDP)/recombinant interleukin-2 (rIL-2) and interferon alfa-2a (IFN alpha) in disseminated malignant melanoma (DMM).

PATIENTS AND METHODS

Between December 1990 and March 1992, 39 patients with biopsy-proven metastatic malignant melanoma (MM), bidimensionally measurable lesions and an Eastern Cooperative Oncology Group (ECOG) performance status < or = 2 entered this protocol. Seventy-nine percent had received previous chemotherapy including platinum complex (15%) and alpha interferon (44%). They received CDDP (100 mg/m2 on day 0) followed by IL-2 18.10(6) IU/m2/d continuous intravenous (IV) infusion from day 3 to day 6 and from day 17 to day 21. The cycle was repeated on day 28. Subcutaneous IFN alpha 9.10(6) IU three times weekly was administered throughout the treatment period. From day 66 or 94, patients were administered a maintenance cycle with CDDP 100 mg/m2, subcutaneous IL-2 5.10(6) IU/m2/d from day 15 to day 19 and from day 22 to day 26 and IFN alpha 9.10(6) IU three times weekly repeated every 5 weeks (maximum four cycles).

RESULTS

Among 39 assessable patients, five patients achieved complete responses (CRs). Sixteen patients had partial responses (PRs). The overall objective response rate was 53.8%. The number of metastatic sites was the only response-predictive factor. Toxicity was manageable in a routine patient setting and there was no life-threatening toxicity.

CONCLUSION

These results seem to indicate a possible synergy between CDDP/rIL-2 and IFN alpha in MM.

Chemoimmunotherapy of metastatic malignant melanoma. The Salpétrière Hospital (SOMPS) experience

Optimistic results were obtained in the treatment of 39 patients with surgically incurable metastatic malignant melanoma using a regimen including 2 to 3 monthly induction cycles of cis-diamminedichloroplatinum (CDDP), recombinant interleukin-2 (rIL-2) and interferon alpha-2a (IFN alpha-2a). 33 of 39 patients were pretreated with chemotherapy (dacarbazine and/or fotemustine:31, CDDP:6) and 17 of 39 with IFN alpha-2a. Overall response rate was 54% with 13% achieving a complete response for up to 59+ weeks. Moderate to severe side-effects were reversible on rIL-2 cessation and toxicity was manageable in a routine inpatient setting. These results are especially encouraging as they were seen in previously treated patients, classically low responders, including 3 who were resistant to cisplatin or other platinum complexes. The question remains if this regimen bypasses traditional mechanisms of drug resistance.