Randomized phase III study of temozolomide versus dacarbazine in the treatment of patients with advanced metastatic malignant melanoma

Vascular endothelial growth factor-A determines detectability of experimental melanoma brain metastasis in GD-DTPA-enhanced MRI

We have previously shown that the dense vascular network in mouse brain allows for growth of human melanoma xenografts (Mel57) by co-option of preexisting vessels. Overexpression of recombinant vascular endothelial growth factor-A (VEGF-A) by such xenografts induced functional and morphologic alterations of preexisting vessels. We now describe the effects of VEGF-A expression on visualization of these brain tumors in mice by magnetic resonance imaging (MRI), using gadolinium diethylenetriaminepenta-acetic acid (Gd-DTPA) and ultra small paramagnetic iron oxide particles (USPIO) as contrast agents. Brain lesions derived from (mock-transfected) Mel57 cells were undetectable in MRI after Gd-DTPA injection. However, the majority of such lesions became visible after injection of USPIO, due to the lower vascular density in the lesions as compared to the surrounding parenchyma. In contrast, VEGF-A-expressing lesions were visualized using Gd-DTPA-enhanced MRI by a rapid circumferential enhancement, due to leaky peritumoral vasculature. USPIO-enhanced MRI of these tumors corroborated the immunohistochemic finding that peritumorally located, highly irregular and dilated vessels were present, while intratumoral vessel density was low. Our study shows that VEGF-A is a key factor in imaging of brain neoplasms. Our data also demonstrate that, at least in brain, blood-pool agent-enhanced MRI may be a valuable diagnostic tool to detect malignancies that are not visible on Gd-DTPA-enhanced MRI. Furthermore, the involvement of VEGF-A in MRI visibility suggests that care must be taken with MRI-based evaluation of antiangiogenic therapy, as anti-VEGF treatment might revert a tumor to a co-opting phenotype, resulting in loss of contrast enhancement in MRI.

Phase II evaluation of temozolomide in metastatic choroidal melanoma

Temozolomide (Temodar) has demonstrated clinical activity against melanoma equivalent to that of intravenous dacarbazine (DTIC). Phase I clinical studies have shown that low dose chronic administration of temozolomide permits the delivery of higher dose intensities than a 5 day dose schedule. Temozolomide is hydrolysed to its active metabolite monomethyltriazenoimidazole carboxamide (MTIC) upon absorption from the gastrointestinal tract, while DTIC is inactive until it is metabolized in the liver to MTIC. In view of this, a higher concentration of MTIC will pass through the liver during the first pass when its source is temozolomide rather than DTIC. To determine if these characteristics of temozolomide will translate into a higher response rate than that achieved with DTIC, we conducted a phase II clinical trial of temozolomide in patients with uveal melanoma metastatic to the liver. Temozolomide was administered orally at a starting dose of 75 mg/m2 per day for 21 days every 4 weeks. Fourteen patients were enrolled in the trial. No complete or partial responses were observed. Stabilization of disease was achieved in two patients. The treatments were well tolerated. We conclude that, like DTIC, temozolomide at the dose and schedule studied in this trial is not effective for the control of metastatic melanoma of uveal origin.

The health-related quality-of-life impact of histamine dihydrochloride plus interleukin-2 compared with interleukin-2 alone in patients with metastatic melanoma

The aim of this study was to compare the quality-of-life (QOL) effects of interleukin-2 (IL-2) alone with those of IL-2 plus histamine dihydrochloride in the setting of a multicenter, randomized trial for patients with metastatic melanoma. QOL data were collected from July 1997 to March 2000 during a phase III trial comparing subcutaneous histamine plus IL-2 and IL-2 alone. Prior to each treatment cycle, patients completed the 76-item Quality-of-Well-Being Scale-Self-Administered (QWB-SA) questionnaire, the Overall State of Health (OSH) item, and the General Health Perception (GHP) item. A longitudinal data analysis using the generalized estimating equations approach was performed to compare changes in QWB-SA scores over time between treatment groups, and predicted QWB-SA scores from the regression analysis were used to calculate quality-adjusted survival duration over the 12-month study period. QOL analyses were conducted for all randomized patients (intent-to-treat overall population, ITT-OA) and all patients who had liver metastases at randomization (ITT-LM population). In the ITT-OA population, differences in QWB-SA scores over time between the histamine plus IL-2 group (150 patients) and the IL-2 alone group (151 patients) were not significant (P=0.511, type III F test). In the ITT-LM population (53 histamine plus IL-2 patients and 73 IL-2 alone patients), changes in QWB-SA scores over time favored the histamine plus IL-2 group (P=0.018, type III F-test). In both the ITT-OA and ITT-LM populations, QWB-SA scores deteriorated more quickly over time in the IL-2 alone group than in the histamine plus IL-2 group, resulting in a significant difference in median quality-adjusted survival duration in favor of the histamine plus IL-2 group by 31.3 days in the ITT-OA population (P=0.007, Mann-Whitney U-test), and 50.2 days in the ITT-LM population (P=0.011). OSH and GHP scores did not differ between groups. The addition of subcutaneous histamine dihydrochloride to IL-2 treatment improved median quality-adjusted survival duration and did not adversely affect QOL in patients with malignant melanoma.

Pharmacology of antineoplastic agents in older cancer patients

Persons over the age of 65 years are the fastest growing segment of the United States population. In the next 30 years it will comprise over 20% of the population. Fifty percent of all cancers occur in this age group and therefore there will be an expected rise in the total cancer burden. Data is becoming available which will better guide the use of chemotherapy in the older patient population. Studies will be presented discussing pharmacokinetic data on a number of chemotherapeutic agents with an emphasis on those which have entered practice over the past few years. Many of these agents seem to have a beneficial therapeutic index, particularly in regard to older patients. There has also been an increasing trend toward the use of oral chemotherapy. Factors that must be considered in choosing chemotherapy include limitations of saturability of absorption, patient compliance and the pharmacokinetic and pharmacodynamic changes which occur in older patients. Interpatient variability and age related changes in drug metabolism are discussed. Careful attention to the physiologic changes with age, and dose adjustments necessary for end organ dysfunction (renal, hepatic) are needed to ensure the safe administration of chemotherapy.

Medical management of melanoma

The treatment for malignant melanoma has undergone significant changes over the past few decades, with biological therapy playing an increasingly important role and replacing the traditional cytotoxic agents as the first-line therapy for this disease, both in advanced disease and adjuvant settings. Despite the developments of new modalities of therapy for melanoma, the outcome for patients with advanced disease remains poor. This article discusses the clinical studies that have shaped our current management of melanoma, both in the adjuvant setting, and in the metastatic setting. Additionally, successes and failures of clinical trials will be discussed, as they will guide the strategic development of future studies in the management of this aggressive disease.

Brain metastases following interleukin-2 plus interferon-alpha-2a therapy: a follow-up study in 94 stage IV melanoma patients

This study analyses the frequency and therapy of brain metastases in 94 stage IV melanoma patients after treatment with high-dose interleukin-2 (IL-2) and interferon-alpha (IFN-alpha) within three subsequent trials between 1990 and 1995. Central nervous system (CNS) metastases occurred in 28 patients (30%) during the potential follow-up period of 6 years. Time to occurrence of brain metastases varied between 1 and 53 months, with a median of 10 months. Of 28 patients, 19 had < 5 metastases, which were treated with stereotactic radiosurgery (SR) in 9 patients. In 2 patients, SR was followed by resection. 9 patients had multiple metastases, of which 4 received whole brain irradiation (WBI). Median survival after the detection of CNS metastases was 6 months (95% Confidence Interval (CI) 1-11 months). SR plus resection was associated with a prolonged survival of 34 and 35 months in 2 patients, 1 patient survived for 41 months after WBI, demonstrating the efficacy of these therapeutic strategies.

The effect of O6-alkylguanine-DNA alkyltransferase and mismatch repair activities on the sensitivity of human melanoma cells to temozolomide, 1,3-bis(2-chloroethyl)1-nitrosourea, and cisplatin

The prognosis of advanced melanoma is generally poor, because this tumor commonly exhibits intrinsic or acquired resistance to chemotherapy. In an attempt to identify the underlying causes of this resistance, we studied the roles played by the DNA repair enzyme O(6)-alkylguanine-DNA alkyltransferase (OGAT) and the mismatch repair (MMR) system in the sensitivity of melanoma cells to temozolomide (TMZ), 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU), or cis-diamminedichloroplatinum(II) (CDDP). To this end, OGAT levels and MMR efficiency of extracts of nine melanoma cell lines and selected clones derived from four of these lines were determined and correlated with the sensitivity of the respective cells to these drugs. The effectiveness of O(6)-benzylguanine (BG), a specific OGAT inhibitor, in potentiating TMZ- or BCNU-mediated cytotoxicity was also evaluated. Our results demonstrate that MMR efficiency and OGAT levels strongly affect melanoma cell sensitivity to TMZ. In MMR-proficient cells, a direct correlation between OGAT levels and TMZ IC(50) values was found. When OGAT activity was inhibited with BG, the sensitivity of these cells to TMZ increased and was then dictated largely by their MMR efficiency. MMR-deficient cells were highly resistant to the drug irrespective of their OGAT levels. Although OGAT activity and MMR status seemed to be the major determinants of melanoma sensitivity to TMZ, this was not the case for BCNU and CDDP; resistance to the latter drugs clearly involves processes other than the two DNA repair pathways analyzed in this study.

Neurologic complications of cancer therapy

Neurologic complications of chemotherapy are relatively common. The diagnosis of chemotherapy-associated neurotoxicity remains a clinical one, and is largely based on the exclusion of other possible causes. The goal of this review is to describe the neurotoxicity associated with established chemothrerapeutic agents and with some of the newer biologic agents, monoclonal antibodies and targeted molecular therapies used in the treatment of cancer.

Temozolomide followed by combined immunotherapy with GM-CSF, low-dose IL2 and IFN alpha in patients with metastatic melanoma

The purpose of this study is to determine the toxicity and efficacy of temozolomide (TMZ) p.o. followed by subcutaneous (s.c.) low-dose interleukin-2 (IL2), granulocyte-monocyte colony stimulating factor (GM-CSF) and interferon-alpha 2b (IFN alpha) in patients with metastatic melanoma. A total of 74 evaluable patients received, in four separate cohorts, escalating doses of TMZ (150-250 mg m(-2)) for 5 days followed by s.c. IL2 (4 MIU m(-2)), GM-CSF (2.5 microg kg(-1)) and IFN alpha (5 MIU flat) for 12 days. A second identical treatment was scheduled on day 22 and cycles were repeated in stable or responding patients following evaluation. Data were analysed after a median follow-up of 20 months (12-30 months). The overall objective response rate was 31% (23 out of 74; confidence limits 20.8-42.9%) with 5% CR. Responses occurred in all disease sites including the central nervous system (CNS). Of the 36 patients with responding or stable disease, none developed CNS metastasis as the first or concurrent site of progressive disease. Median survival was 252 days (8.3 months), 1 year survival 41%. Thrombocytopenia was the primary toxicity of TMZ and was dose- and patient-dependent. Lymphocytopenia (grade 3-4 CTC) occurred in 48.5% (34 out of 70) fully monitored patients following TMZ and was present after immunotherapy in two patients. The main toxicity of combined immunotherapy was the flu-like syndrome (grade 3) and transient liver function disturbances (grade 2 in 20, grade 3 in 15 patients). TMZ p.o. followed by s.c. combined immunotherapy demonstrates efficacy in patients with stage IV melanoma and is associated with toxicity that is manageable on an outpatient basis.

Farnesyl thiosalicylic acid chemosensitizes human melanoma in vivo

Malignant melanoma is well known for its poor response to a variety of chemotherapeutic agents. Testing of numerous treatment strategies has identified dacarbazine as the most active single drug; however, its response rates in various clinical settings are quite limited. Defective apoptosis in combination with oncogenic proteins (such as activated Ras) in cell proliferation pathways plays a key part in both the development and disease progression of human melanoma. Farnesyl thiosalicylic acid, a novel Ras inhibitor, dislodges Ras proteins from the cell membrane, leading to inhibition of cell transformation and tumor growth. In this study we evaluated the effect of farnesyl thiosalicylic acid treatment on established human melanoma xenografts grown in mice with severe combined immunodeficiency as well as the chemosensitizing effect of farnesyl thiosalicylic acid in combination with dacarbazine. Daily administration of 10, 20, or 40 mg per kg of farnesyl thiosalicylic acid resulted in a concentration-dependent reduction in tumor growth, with growth inhibition reaching a mean value of 45+/-7%, at the highest concentration. The combination of farnesyl thiosalicylic acid (10 mg per kg per day) and dacarbazine (80 mg per kg per day) resulted in a significant reduction of 56%+/-9%, in mean tumor growth. Analysis of toxicologic parameters (mouse weight, blood cell counts, and blood chemistry) showed an acceptable and similar toxicity profile for both the single-agent farnesyl thiosalicylic acid treatment and the combination of farnesyl thiosalicylic acid plus dacarbazine treatment. Given the observed preclinical treatment responses and the low toxicity, our results support the notion that farnesyl thiosalicylic acid in combination with dacarbazine may qualify as a rational treatment approach for human melanoma.

Temozolomide in combination with interferon alpha-2b in patients with metastatic melanoma: a phase I dose-escalation study

BACKGROUND

Metastatic melanoma (MM) is associated with a high risk of central nervous system (CNS) metastases, and current chemotherapy does not adequately treat or protect patients with MM against CNS metastases. Therefore, the authors initiated a Phase I study to determine the pharmacokinetics and safety profile of temozolomide (TMZ), a novel oral alkylating agent known to cross the blood-brain barrier, in combination with interferon alpha-2b (IFN-alpha2b).

METHODS

Twenty-three patients with MM were enrolled in this single-center, open-label study. Patients with CNS metastasis were excluded. One cohort (n = 6 patients) received oral TMZ (200 mg/m(2) per day) for 5 days every 28-day cycle plus subcutaneous IFN-alpha2b (5 million International Units [MIU]/m(2) per day, 3 times per week). A second cohort (n = 17 patients) received TMZ 150 mg/m(2) per day on the same schedule plus escalating doses of IFN-alpha2b (5.0 MIU/m(2) per day, 7.5 MIU/m(2) per day, and 10 MIU/m(2) per day 3 times per week).

RESULTS

The most common adverse events were fatigue, fever, nausea/emesis, anxiety, and diarrhea. Most toxicity was mild to moderate in severity. The primary dose-limiting toxicity was thrombocytopenia. The maximum tolerated dose was either TMZ 150 mg/m(2) plus IFN-alpha2b 7.5 MIU/m(2) or TMZ 200 mg/m(2) plus IFN-alpha2b 5.0 MIU/m(2). Four patients (17%) had objective responses (one complete response and three partial responses), and four patients had stable disease. The median survival was 9 months. The pharmacokinetics of TMZ were not affected by coadministration of IFN-alpha2b.

CONCLUSIONS

TMZ can be combined safely with IFN-alpha2b. This regimen demonstrated clinical activity in patients with MM and merits further investigation to define its effect on the incidence of brain metastases.

Malignant mucosal melanoma of the head and neck

Mucosal melanomas comprise about 1% of all malignant melanomas and exhibit far more aggressive behaviour than that of skin melanomas: they are more inclined to metastatize into regional and distant sites or recur locally, regionally or in distant locations, resulting in a high rate of cause-specific death. Mucosal melanomas in the head and neck region account for half of all mucosal melanomas, occurring mainly in the upper respiratory tract, oral cavity and pharynx. They appear with equal gender distribution and with a peak incidence in the age range 60-80 years. In consequence of their hidden location, they are usually diagnosed in a locoregionally advanced clinical stage, with a rate of 5-48% of regional and 4-14% of distant dissemination. The typical therapeutic approach is surgery, postoperative irradiation and systemic therapy. Local control with either surgery or radiotherapy is frequently (60- 70%) achieved, but the rates of local, regional and distant recurrences are high (50-90%, 20-60% and 30-70%, respectively). The reported 5-year actual survival rates are poor (17-48%), which is attributed mainly to a haematogenous dissemination. These characteristics demonstrate that identification of the precursor lesions and more effective local and systemic approaches are needed to improve the therapeutic results.

Inhibition of telomerase increases resistance of melanoma cells to temozolomide, but not to temozolomide combined with poly (adp-ribose) polymerase inhibitor

In the present study, we have investigated the influence of telomerase inhibition in chemosensitivity of melanoma cells to temozolomide (TMZ), a methylating agent with promising antitumor activity against metastatic melanoma. In fact, telomerase, a ribonucleoprotein enzyme expressed in the majority of tumors, is presently considered an attractive target for anticancer therapy, with the double aim of reducing tumor growth and increasing chemosensitivity of cancer cells. Susceptibility to TMZ and to other antitumor agents used for treatment of metastatic melanoma was initially assessed in melanoma lines with different basal levels of telomerase activity. Thereafter, chemosensitivity was investigated after inhibition of telomerase by means of stable transfection of a catalytically inactive, dominant-negative mutant of hTERT (DN-hTERT). This study shows for the first time that: a) susceptibility to TMZ of melanoma lines derived from the same patient did not depend on basal telomerase activity; b) inhibition of telomerase by DN-hTERT resulted in reduced growth rate and increased resistance to TMZ and to the chloroethylating agent carmustine, increased sensitivity to cisplatin, and no change in response to tamoxifen or to a selective N3-adenine methylating agent; c) inhibition of poly(ADP-ribose) polymerase (PARP), an enzyme involved in the repair of N-methylpurines, restored sensitivity of DN-hTERT clones to TMZ. These results indicate that a careful selection of the antitumor agent has to be made when antitelomerase therapy is combined with chemotherapy. Moreover, the data presented here suggest that TMZ + PARP inhibitor combination is active against telomerase-suppressed and slowly growing tumors.

Immunophenotypical markers, ultrastructure and chemosensitivity profile of metastatic melanoma cells

The survival of patients affected by cutaneous melanoma has improved dramatically in the last 10 years, because of earlier diagnosis. Despite this, the therapeutic results obtained in metastatic melanoma (MM) are very disappointing due to its poor responsiveness to cytotoxic agents. In this type of solid tumor, tumor chemosensitivity assays have been suggested to be an important tool to predict clinical responsiveness to therapy. Metastatic melanoma cells (MMCs) were obtained from subcutaneous melanoma metastases of five patients and cultured for several consecutive passages. An immunofluorescence and an electron microscopic study were performed in order to establish the ultrastructural and physiopathological features of MMCs. A sulphorodamine-B test was used to measure in vitro sensitivity of MMCs to temozolomide, cisplatin, vindesine, taxol and interpheron alpha-2a. Following a 72 h exposure, maximum activity was obtained with vindesine (median inhibitory concentration, IC(50), 0.23 nM) and taxol (median IC(50) 0.31 nM). Cisplatin median IC(50) values were higher (4.6 microM) than taxol and vindesine, but still in the range of clinically achievable plasma concentrations. Temozolomide inhibited cell proliferation only at very high concentrations (median IC(50) 228 microM). No significant cell growth inhibitory effects (<or=25%) were observed with interferon alpha-2a concentrations up to 8000 IU/ml. MMCs expressed progression markers typical of cutaneous metastatic melanoma and showed poor sensitivity in vitro to most anticancer drugs tested, including temozolomide.

PET for in vivo pharmacokinetic and pharmacodynamic measurements

Positron emission tomography (PET) scanning is evolving as a unique tool for drug development in oncology for improving both the efficacy of established treatment and in evaluating novel anticancer agents. As a non-invasive functional imaging modality, PET has an unrivalled sensitivity when monitoring the pharmacokinetics and pharmacodynamics of drugs and biochemicals when radiolabelled with short living positron-emitting radioisotopes. This is of particular relevance in assessing newer molecular-targeted therapy where conventional evaluation criteria (maximum tolerated dose and tumour shrinkage for example) may be inappropriate. PET has already been applied to a wide number of drugs to demonstrate activity in vivo from standard chemotherapy such as 5-fluorouracil (5-FU) [J Clin Oncol 17 (1999) 1580], to novel molecular agents such as those involved in tumour angiogenesis [Br J Cancer 83 (2000) P6] and antivascular therapy [Proc Annu Meet Am Soc Clin Oncol 19 (2000) 179a]. This review will evaluate the achievements of PET in the drug development process, an approach that promises to facilitate the rapid translation of scientific research into current clinical practice.

Biochemotherapy of melanoma

Despite the evaluation of many different chemotherapy and immunotherapy drugs, the median survival in metastatic melanoma remains in the range of 6 to 9 months. Combination chemotherapy or combination immunotherapy has not produced a significant advantage over single-agent therapy but is associated with greater toxicity. Based on the potential for additive or synergistic activity with the combination of chemotherapy and biotherapy, many investigators have evaluated biochemotherapy in patients with advanced melanoma. Aggregate results suggest that biochemotherapy is tolerable and produces a response rate in the range of 50% with a complete response rate of 10%. Although these phase II results appear superior to previous results with chemotherapy or immunotherapy alone, the true benefits of biochemotherapy can only be determined with the results of randomized phase III trials; therefore, biochemotherapy should be considered an as yet experimental therapy. Many other issues regarding biochemotherapy, such as sequence, outpatient administration, and use in the adjuvant setting, for stage III melanoma are being actively evaluated.

Quality of life in patients with malignant melanoma participating in a phase I trial of an autologous tumour-derived vaccine

Quality of life (QOL) plays an increasingly important role in the decision-making process and the ultimate acceptability of particular treatments for patients. We prospectively examined QOL in patients with advanced melanoma treated with surgery followed by heat-shock protein peptide complex 96 (HSPPC-96) vaccine, an active, patient-specific immunotherapy. QOL (the RAND 36-Item Health Survey; SF-36) and cancer-related intrusive thoughts (Impact of Event Scale; IES) were measured at the start of treatment, 3 weeks later on the final day of treatment, and at follow-up 1 month later in 30 patients with stage III or IV malignant melanoma. Mixed model analyses revealed no significant change over time in the SF-36 Physical or Mental Component Summary scores, or the IES scores. In comparisons with other populations, at the 1 month follow-up assessment, melanoma patients reported similar QOL to patients with metastatic renal cell carcinoma who received the same treatment, significantly worse QOL on the physical dimensions and similar QOL on the psychosocial and emotional dimensions compared with the general population, similar QOL to patients with type II diabetes, and significantly better QOL on all three dimensions than patients with congestive heart failure. There was also a significant negative association between IES scores at baseline and mental health scores at each time point ( < 0.002 for all). QOL remained stable during treatment with the HSPPC-96 vaccine. In addition, patients who reported high levels of cancer-related intrusive thoughts at the start of treatment reported worse mental health at the end of the treatment.

The treatment of brain metastases from malignant melanoma

Metastasis to the CNS develops in nearly half of patients with advanced melanoma; in 15% to 20% of these patients, the CNS is the first site of relapse. While systemic therapy for metastatic melanoma produces objective responses in 15% to 50% of patients, the available drugs do not penetrate well into the CNS, and these patients rarely benefit from systemic therapy. Although brain metastasis may be treated with surgery and/or stereotactic radiosurgery (SRS) when disease is limited to approximately one to three lesions, treatment for patients with large or multiple metastases is limited to whole brain irradiation (WBRT). While formal response and survival analyses of the impact of WBRT in melanoma have not been reported, the estimated median survival time for unselected patients with CNS metastases is only 2 to 4 months, with 1-year survival rates of less than 13%. In a selected population of patients with limited CNS involvement, surgical resection alone or in combination with WBRT appears to prolong median survival. More recently, SRS has been shown to be an effective local treatment for selected patients with brain metastases. In several retrospective reports of patients with melanoma CNS metastases, treatment with surgical resection alone or in combination with WBRT has been demonstrated to prolong median survival. More recently, SRS has been shown to be an effective local treatment for selected patients with brain metastases. In several retrospective reports, patients with CNS metastases from melanoma treated with a combination of WBRT plus SRS or SRS alone had median survivals and rates of control in the CNS superior to published reports for traditional WBRT. Most of these patients died from progressive extracranial disease with locally controlled CNS disease. Investigation of the contribution of newer systemic agents to the control of melanoma metastatic to the CNS has been based on the identification of drugs that have antitumor activity and the ability to cross the blood-brain barrier. Fotemustine is a nitrosourea that produced similar activity in CNS metastasis as in systemic disease, with a response rate of about 25%. Temozolomide (TMZ) is an oral alkylating agent that acts via the same mechanism as dacarbazine (DTIC), the most active single agent in melanoma. TMZ, which is highly active in brain tumors, has also been associated with activity in systemic and CNS metastases in melanoma patients, also in the 25% range. Efforts are underway to assess the additive benefit of TMZ and other drugs to WBRT or focused radiotherapy in this disease.

Metastatic melanoma: chemotherapy

The incidence of cutaneous melanoma has been rapidly increasing, with an estimate of 47,700 new cases diagnosed in 2000 in the United States. In the early phase of its natural history, melanoma is cured in most cases by surgery, but once the metastatic phase develops, it is almost always fatal. The treatment of metastatic melanoma remains unsatisfactory. Systemic therapy has not been successful up to now, with very low response rates to single-agent chemotherapy. Polychemotherapy has increased the response rate (RR), without a significant improvement in overall survival. Immunotherapy alone is able to induce only a few durable complete responses (CRs). New chemotherapeutic and biologic agents are now available and promising combined approaches targeting the tumor by several different mechanisms are desirable and will probably represent the future modality of treatment.

Brain metastases in melanoma: a European perspective

CNS involvement is a common feature of metastatic melanoma. Despite this, there is little evidence upon which clinicians can base decisions about treatment. The short prognosis and significant symptoms usually associated with melanoma brain metastases have excluded these patients from clinical trials. In Europe the standard treatment involves whole brain radiotherapy, although selected centers offer other modalities, including surgery, radiosurgery, and chemotherapy.

Hemorrhagic cystitis as an unexpected adverse reaction to temozolomide: case report

A case is reported in which temozolomide, a promising new DNA alkylating agent, was successfully used to treat radiation refractory metastatic brain tumors arising from primary breast cancer. However, the treatment had to be terminated after the second round of treatment due to the development of hemorrhagic cystitis. This side effect was totally unexpected. Another class of alkylating agents (cyclophosphamide and related compounds) exhibits this side effect caused by a prevalent acrolein metabolite. Temozolomide and its sister compounds, dacarbazine and 5-(3-methyltriazen-1-yl)imidazole-4-caroxamide, have never been reported to have this adverse reaction. This case serves to alert physicians to the existence of a possible subpopulation of patients who may experience hemorrhagic cystitis on treatment with imidazotetrazines by a mechanism that is yet to be established.

Chemotherapy approaches to melanoma

Melanoma, if detected early, is a curable malignancy. Unfortunately, however, many melanomas are detected at the stage that puts patients at a high risk of recurrence, if they are not already metastatic. New techniques are being developed to try to detect subclinical disease and allow for early intervention with adjuvant treatment. Because the incidence of melanoma is on the rise, there is a greater demand to improve the current therapy. Revision of the American Joint Committee on Cancer staging system has enabled patients to be stratified better into risk groups, which in turn dictates treatment recommendations. As evidenced by the data provided, the current chemotherapeutic options for metastatic melanoma are far from optimal. Clearly, in this malignancy, enrollment into a clinical trial is an excellent option for patients. The development of novel approaches to treating this disease provide hope for better management and possible cure of a notoriously aggressive disease with a dismal prognosis.

Systemic chemotherapy for the treatment of metastatic melanoma

The role of systemic chemotherapy in the treatment of patients with metastatic melanoma remains of questionable benefit. Despite encouraging phase II data from multiple institutions that suggested an improved overall response rate for patients treated with the Dartmouth regimen, recently completed phase III trials have failed to demonstrate a significant benefit in survival. Of concern is the fact that there have been relatively few new chemotherapeutic agents in the past several years that have demonstrated any activity in this disease. More recently there has been a shift away from combination chemotherapy to biochemotherapy. However, this approach has yet to be clearly defined as superior. The basis for optimism in the future in this field resides in the realm of molecular oncology. As mechanisms of resistance are identified, new molecules such as antisense oligonucleotides may provide the basis for increasing the sensitivity of melanoma to chemotherapeutic and/or immunotherapeutic treatments.

Phase II randomized trial of temozolomide and concurrent radiotherapy in patients with brain metastases

PURPOSE

To determine the efficacy, tolerability, and safety of concurrent temozolomide and radiotherapy in patients with previously untreated brain metastases.

PATIENTS AND METHODS

Fifty-two patients with brain metastases from solid tumors were randomized to oral temozolomide (75 mg/m(2)/d) concurrent with 40-Gy fractionated conventional external-beam radiotherapy (2 Gy, 5 d/wk) for 4 weeks versus 40-Gy radiotherapy alone. The group receiving temozolomide and radiotherapy continued temozolomide therapy (200 mg/m(2)/d) for 5 days every 28 days for an additional six cycles. The primary end points were radiologic response and neurologic symptom evaluation.

RESULTS

The objective response rate was significantly (P =.017) improved in patients receiving temozolomide and radiotherapy versus radiotherapy alone. Among 24 patients assessable for response in the temozolomide group, 23 (96%) of 24 responded, including nine (38%) patients with a complete response and 14 (58%) patients with a partial response. With radiotherapy alone, 14 (67%) of 21 assessable patients responded, including seven (33%) complete responses and seven (33%) partial responses. There was marked neurologic improvement in the group receiving temozolomide, and the proportion of patients requiring corticosteroids 2 months after treatment was lower in the temozolomide group compared with radiotherapy alone (67% v 91%, respectively). Daily temozolomide concurrent with radiotherapy was generally well tolerated; however, grade >or= 2 nausea (48% v 13%, P =.13) and vomiting (32% v 0%, P =.004) were significantly increased in the temozolomide group. Hematologic toxicity was predictable and reversible.

CONCLUSION

Temozolomide is safe, and a significant improvement in response rate was observed when administered in combination with radiotherapy in patients with previously untreated brain metastases. A larger randomized trial is warranted to verify these results.

Effect of O6-(4-bromothenyl)guanine on different temozolomide schedules in a human melanoma xenograft model

The DNA repair protein O(6)-alkylguanine DNA alkyltransferase (ATase) is a major component of resistance to treatment with methylating agents and nitrosoureas. Inactivation of the protein, via the administration of pseudosubstrates, prior to chemotherapy has been shown to improve the latter's therapeutic index in animal models of human tumours. We have also shown that rational scheduling of temozolomide, so that drug is administered at the ATase nadir after the preceding dose, increases tumour growth delay in these models. We now report the results of combining these two approaches. Nude mice bearing A375M human melanoma xenografts were treated with vehicle or 100 mg/kg temozolomide ip for 5 doses spaced 4, 12 or 24 hr apart. Each dose was preceded by the injection of vehicle or 20 mg/kg 4BTG. All treatments resulted in significant delays in tumour quintupling time compared with controls: by 6.2, 5.9 and 16.8 days, respectively, for 24-, 12- and 4-hourly temozolomide alone and by 22.3, 21.3 and 22.1 days, respectively, in combination with 4BTG. Weight loss due to TMZ was unaffected by the presence of 4BTG. This was of the order of 6.2-10.6% with 24- and 12-hourly administration and 17.4-20.1% (p < 0.0001) with 4-hourly treatment. In our model, combining daily temozolomide with 4-BTG confers increased antitumour activity equivalent to that achieved by compressing the temozolomide schedule but with less toxicity. Using temozolomide schedule compression with 4-BTG does not improve on this result, suggesting that ATase inactivation with pseudosubstrates is a more promising means of enhancing the activity of temozolomide than compressed scheduling.

Pharmacokinetic considerations of oral chemotherapy in elderly patients with cancer

Persons over the age of 65 years are the fastest growing segment of the US population. In the next 30 years they will comprise over 20% of the population. Fifty per cent of all cancers occur in this age group and therefore there will be an expected rise in the total cancer burden. There has been an increasing trend over the past 20 years toward the use of oral chemotherapy. This change has been encouraged by the need to decrease the costs of chemotherapy administration, patient preferences and quality of life issues. Factors that must be considered with oral chemotherapy administration include limitations of saturability of absorption, patient compliance and pharmacokinetic/pharmacodynamic changes which occur in elderly patients. Interpatient variability and drug metabolism, particularly age-related changes in drug metabolism are being studied. The cytochrome P450 system has been intensively studied because of its importance with regard to chemotherapeutic drugs. This article reviews these issues and provides details regarding specific drugs including temozolomide, thalidomide, topotecan, the fluoropyrimidines, etoposide, hydroxycarbamide (hydroxyurea), tamoxifen, and alkylating drugs. Complementary and alternative therapies are also discussed.

Oblimersen Bcl-2 antisense: facilitating apoptosis in anticancer treatment

The components of the apoptotic program are targets for anticancer therapy. Bcl-2 protein inhibits apoptosis and confers resistance to treatment with traditional cytotoxic chemotherapy, radiotherapy, and monoclonal antibodies (mAb). Oblimersen sodium (G3139, Genasense, Genta Inc., Berkeley Heights, NJ) is an antisense oligonucleotide (AS-ON) compound designed to specifically bind to the first 6 codons of the human bcl-2 mRNA sequence, resulting in degradation of bcl-2 mRNA and subsequent decrease in Bcl-2 protein translation. Oblimersen is the first oligonucleotide to demonstrate proof of principle of an antisense effect in human tumors by the documented downregulation of the target Bcl-2 protein. A growing body of preclinical and clinical evidence suggests that oblimersen synergizes with many cytotoxic and biologic/immunotherapeutic agents against a variety of hematologic malignancies and solid tumors. Randomized clinical trials are currently underway to evaluate the efficacy and tolerability of oblimersen in combination with cytotoxic chemotherapy in chronic lymphocytic leukemia, multiple myeloma, malignant melanoma, and non-small cell lung cancer. In addition, nonrandomized trials are under way to evaluate oblimersen in non-Hodgkin's lymphoma, acute myeloid leukemia, and hormone-refractory prostate cancer. Preclinical data also support the clinical evaluation of oblimersen in additional tumor types, including chronic myelogenous leukemia and breast, small cell lung, gastric, colon, bladder, and Merkel cell cancers. Enhancement of the efficacy of anticancer treatments with oblimersen Bcl-2 antisense therapy represents a promising new apoptosis-modulating strategy, and ongoing clinical trials will test this therapeutic approach.

Temozolomide plus thalidomide in patients with advanced melanoma: results of a dose-finding trial

PURPOSE

To establish a safe and tolerated regimen of an oral cytotoxic agent, temozolomide, and a cytostatic agent, thalidomide, in patients with unresectable stage III or IV malignant melanoma.

PATIENTS AND METHODS

Patients with unresectable stage III or IV melanoma without brain metastases were entered successively onto four treatment cohorts: level 1, temozolomide 50 mg/m(2)/d for 6 weeks followed by a 4-week break; levels 2, 3, and 4, temozolomide 75 mg/m(2)/d for 6 weeks followed, respectively, by breaks of 4, 3, and 2 weeks. Thalidomide was started at 200 mg/d, and escalated to a maximum dose of 400 mg/d. Safety was assessed at weeks 2 and 4 and every 4 weeks thereafter; tumor response was evaluated every 8 to 10 weeks.

RESULTS

Twelve patients were enrolled, three on each cohort. Therapy was generally well tolerated on all of the treatment schedules. Thalidomide at a dose of 400 mg/d was well tolerated in patients younger than 70, and 200 mg/d was well tolerated in older patients. The most common adverse events were grade 2 or 3 constipation and neuropathy, which were attributed to thalidomide. Five major responses (one complete, four partial) were documented, all at dose levels 2 to 4. Three of the five responding patients were in the over-70 age group. The median duration of response was 6 months (range, 4 to 17+ months), and the median overall survival was 12.3 months (range, 4 to 19+ months).

CONCLUSION

The combination of temozolomide and thalidomide was well tolerated and had antitumor activity in patients with advanced melanoma, including elderly patients over 70 years old.

A phase II EORTC study of temozolomide in patients with malignant pleural mesothelioma

The aim of this study was to investigate the anti-tumour activity of temozolomide in patients with malignant pleural mesothelioma. 27 chemotherapy-naïve patients with histologically-proven malignant mesothelioma were treated with temozolomide 200 mg/m2/day, given orally on days 1-5 of each 28-day cycle. Therapy continued up to 10 cycles unless disease progression or excessive toxicity mandated discontinuation. Toxicity, symptom improvement and pain intensity were regularly assessed. With a median relative dose intensity of 97%, toxicity was moderate with grade 3 or more nausea, vomiting, thrombocytopenia, leucocytopenia, neutropenia, febrile leucocytopenia, arthralgia, infection and fever with infection occurring in 13, 13, 10, 3, 7 and 3% of patients for the remaining events, respectively. Overall, 1 objective response was observed (response rate 4%, 95% Confidence Interval (CI): 0.1-19). Median survival was 8.2 months. Symptom assessment showed no improvement and an increase of pain was observed during the study. Thus, oral temozolomide is an inactive agent in malignant mesothelioma.

Effect of temozolomide on central nervous system relapse in patients with advanced melanoma

Temozolomide has shown efficacy in the treatment of metastatic melanoma similar to that of dacarbazine (DTIC), the standard chemotherapy, but with the added benefit of penetration into the central nervous system (CNS). Isolated CNS relapse is increasingly a problem for patients who respond to biochemotherapy. By replacing DTIC with temozolomide in treatment regimens, the incidence of CNS relapse might be reduced. This hypothesis is difficult to test in a prospective randomized controlled trial because of the large number of patients that would be required. We have examined this question in a retrospective case control study, observing the rates of CNS relapse in advanced metastatic melanoma patients responding to DTIC- or temozolomide-based chemotherapy in three institutions. Twenty-one DTIC and 20 temozolomide responders were identified, and have been followed up for a median of 19.0 months (range 6.0-74.3 months). CNS relapse occurred in nine DTIC- and two temozolomide-treated patients, a statistically significant difference in favour of the new agent (P = 0.03). These results support the investigation of temozolomide as a replacement for DTIC in systemic treatment regimens for melanoma.

Biochemical changes associated with a multidrug-resistant phenotype of a human glioma cell line with temozolomide-acquired resistance

Temozolomide (TMZ) is a newly approved alkylating agent for the treatment of malignant gliomas. To investigate resistance mechanisms in a multidrug therapeutic approach, a TMZ-resistant human glioma cell line, SF188/TR, was established by stepwise exposure of human SF188 parental cells to TMZ for approximately 6 months. SF188/TR showed 6-fold resistance to TMZ and cross-resistance to a broad spectrum of other anticancer agents that included 3-5-fold resistance to melphalan (MEL), gemcitabine (GEM), paclitaxel (PAC), methotrexate (MTX), and doxorubicin (DOX), and 1.6-2-fold resistance to cisplatin (CDDP) and topotecan (TPT). Alkylguanine alkyltransferase (AGT) activity was increased significantly in the resistant cell line compared with the parental cell line (P<0.05), whereas no significant differences occurred in the cellular uptake of TMZ and PAC between resistant and parental cells. Depletion of AGT by O(6)-benzylguanine significantly increased the cytotoxicity of TMZ in both the sensitive and resistant cell lines, but did not influence the cytotoxicity of the other drugs tested. Treatment with TMZ caused SF188 cells to accumulate in S phase, whereas SF188/TR cells were unaffected. Expression of Bcl-2 family members in SF188/TR cells compared with SF188 cells indicated that the pro-apoptotic proteins (i.e. Bad, Bax, Bcl-X(S)) were reduced 2-4-fold in the resistant cell line, whereas the anti-apoptotic proteins Bcl-2 and Bcl-X(L) were expressed at similar levels in both cell lines. In conclusion, the mechanism of resistance of SF188/TR cells to TMZ involved increased activity of AGT, a primary resistance mechanism, whereas the broad cross-resistance pattern to other anticancer drugs was due to a common secondary resistance mechanism related to alterations in the relative expression of the pro-apoptotic and anti-apoptotic proteins.

Combined treatment with temozolomide and poly(ADP-ribose) polymerase inhibitor enhances survival of mice bearing hematologic malignancy at the central nervous system site

Temozolomide (TZM) is a DNA-methylating agent that has recently been introduced into various clinical trials for treatment of solid or hematologic neoplasias, including brain lymphomas. In the current study, we have investigated whether the antitumor activity of TZM could be selectively enhanced at the central nervous system (CNS) site by intracerebral injection of a poly(ADP-ribose) polymerase (PARP) inhibitor. Mice were injected intracranially with lymphoma cells. The PARP inhibitor NU1025 (1 mg/animal) was delivered intracerebrally, whereas TZM was given as a single or a fractionated dose of 200 mg/kg by intraperitoneal administration. Results indicated that this drug combination significantly enhanced the survival of tumor-bearing mice and that this fractionated modality of treatment was the most effective schedule. Increased survival time was related to a marked reduction of tumor growth, as evidenced by histologic studies. Treatment with TZM alone was ineffective. This is the first report exploring in vivo the combination of TZM with PARP inhibitor for intracerebral neoplasias.

Potential clinical applications of poly(ADP-ribose) polymerase (PARP) inhibitors

Poly(ADP-ribose) polymerases (PARPs) are defined as cell signaling enzymes that catalyze the transfer of ADP-ribose units from NAD(+)to a number of acceptor proteins. PARP-1, the best characterized member of the PARP family, that presently includes six members, is an abundant nuclear enzyme implicated in cellular responses to DNA injury provoked by genotoxic stress (oxygen radicals, ionizing radiations and monofunctional alkylating agents). Due to its involvement either in DNA repair or in cell death, PARP-1 is regarded as a double-edged regulator of cellular functions. In fact, when the DNA damage is moderate, PARP-1 participates in the DNA repair process. Conversely, in the case of massive DNA injury, elevated PARP-1 activation leads to rapid NAD(+)/ATP consumption and cell death by necrosis. Excessive PARP-1 activity has been implicated in the pathogenesis of numerous clinical conditions such as stroke, myocardial infarction, shock, diabetes and neurodegenerative disorders. PARP-1 could therefore be considered as a potential target for the development of pharmacological strategies to enhance the antitumor efficacy of radio- and chemotherapy or to treat a number of clinical conditions characterized by oxidative or NO-induced stress and consequent PARP-1 activation. Moreover, the discovery of novel functions for the multiple members of the PARP family might lead in the future to additional clinical indications for PARP inhibitors.

Temozolomide in combination with docetaxel in patients with advanced melanoma: a phase II study of the Hellenic Cooperative Oncology Group

PURPOSE

Temozolomide is a novel oral alkylating agent that is effective against melanoma. Moreover, temozolomide readily crosses the blood-brain barrier and may consequently be effective in patients with brain metastases. This phase II study was performed to assess the efficacy and safety of the combination regimen of temozolomide and docetaxel in patients with advanced metastatic melanoma.

PATIENTS AND METHODS

Sixty-five patients with metastatic melanoma were enrolled. Treatment consisted of intravenous docetaxel (80 mg/m(2)) on day 1 and oral temozolomide (150 mg/m(2)) on days 1 to 5, every 4 weeks, for a maximum of six cycles.

RESULTS

Sixty-two patients were eligible for the efficacy and safety analysis. Seventeen patients (27%) achieved an objective response, including five complete (8%) and 12 partial responses (19%). Median response duration was 9.5 months. Among responders, median time to progression (TTP) was 11.2 months and median overall survival (OS) was 16 months. For all treated patients, the median TTP was 4 months and median OS was 11 months. Three (38%) of eight patients who presented with brain metastases had a partial response for 5, 6, and 12 months. Of 52 patients who did not have brain involvement at presentation, only four (8%) developed brain metastases at a median follow-up of 14 months. Myelosuppression was the primary toxicity.

CONCLUSION

The combination of temozolomide and docetaxel was effective and well tolerated as first-line treatment for patients with advanced metastatic melanoma and demonstrated encouraging antitumor activity against brain metastases.

Metastatic melanoma: chemotherapy to biochemotherapy

BACKGROUND

Single-agent or combination chemotherapy regimens have not impacted the short median survival of patients with metastatic melanoma, and complete or durable responses are rare. Biologic response modifiers (interferon and interleukin-2) have produced durable remissions in a small cohort of patients, and phase II trials of biochemotherapy suggest more benefit.

METHODS

The authors retrospectively reviewed the status of the current treatments of metastatic melanoma focusing on biochemotherapy.

RESULTS

Regimens include both sequential and concurrent approaches for inpatient and outpatient treatment settings. Overall response rates in phase II trials are 40% to 60% with complete responses of 10% to 20% and median survivals in the 11- to 12-month range. Modifications of concurrent biochemotherapy regimens have maintained efficacy and reduced toxicity. Small phase III trials suggest a survival advantage of biochemotherapy (P=.05).

CONCLUSIONS

Biochemotherapy remains a promising new treatment for metastatic melanoma. A large Intergroup trial E3695 comparing concurrent biochemotherapy to combination chemotherapy alone is powered to answer important survival questions.

Results from a randomized phase III study comparing combined treatment with histamine dihydrochloride plus interleukin-2 versus interleukin-2 alone in patients with metastatic melanoma

PURPOSE

Reactive oxidative species (ROS) produced by phagocytic cells have been ascribed a role in the localized suppression of lymphocyte function within malignant tumors. Histamine has been shown to inhibit ROS formation and possibly synergize with cytokines to permit activation of natural killer cells and T cells. This study was designed to determine whether the addition of histamine to a subcutaneous (SC) regimen of interleukin-2 (IL-2) would improve the survival of metastatic melanoma patients.

PATIENTS AND METHODS

A phase III, multicenter, randomized, parallel group study comparing IL-2 plus histamine with IL-2 alone was conducted in 305 patients with advanced metastatic melanoma. Patients were randomized to IL-2 (9 MIU/m(2) bid SC on days 1 to 2 of weeks 1 and 3, and 2 MIU/m(2) bid SC on days 1 to 5 of weeks 2 and 4) with or without histamine (1.0 mg bid SC days 1 to 5, weeks 1 to 4). The primary end point, survival, was prospectively applied to all randomized patients (intent-to-treat-overall population, ITT-OA) and all patients having liver metastases at randomization (ITT-LM population). Secondary end points included safety of the combined treatment, time to disease progression, and response rate.

RESULTS

Combined treatment with histamine plus IL-2 significantly improved overall survival in the ITT-LM population (P =.004) and showed a trend for improved survival in the ITT population (P =.125). Grade 3 and 4 adverse events were comparable in the two arms.

CONCLUSION

Use of histamine as an adjunct to IL-2 is safe, well tolerated, and associated with a statistically significant prolongation of survival compared with IL-2 alone in metastatic melanoma patients with liver involvement. Further trials to confirm and understand the role of histamine in this combination treatment are underway.

Randomized clinical trials in melanoma

Efforts to improve the survival of patients with metastatic melanoma have led to 67 prospective randomized clinical trials investigating the use of agents comprising three main areas of therapy: systemic chemotherapy-based regimens, immunotherapy, and vaccine therapy

Drug-resistance in human melanoma

Advanced malignant melanoma has a poor prognosis since chemotherapy is mostly ineffective due in part to the intrinsic and/or extrinsic resistance of melanoma cells to systemic treatment with anti-neoplastic agents. The reasons for the chemoresistant phenotype are unknown. The relevance of well-analyzed drug-resistance mechanisms, e.g., intracellular/extracellular transport and induction of certain enzyme systems, is reviewed. Most anti-cancer drugs kill susceptible cells through induction of apoptosis. Therefore, it appears that differences in the apoptotic pathways which lead to apoptotic deficiency may account for the ability of some tumor cells to resist drug therapy. Human melanomas, which are characteristically drug-resistant, are more likely to have altered apoptotic pathways and fewer pro-apoptotic molecules. Tumor cells with these characteristics are seldom sensitive to drugs. The complexity of the molecular variants involved in signal transduction along apoptotic pathways suggests that the cell may have a variety of possibilities for regulating apoptosis and generating apoptotic deficiency. Thus, apoptosis and apoptotic deficiency should be analyzed to better clarify the mechanisms of melanoma resistance.

Temozolomide: a novel oral alkylating agent

Temozolomide is an imidazotetrazine with a mechanism of action and efficacy similar to dacarbazine (DTIC). However, it differs from DTIC in that it can be taken orally, degrades spontaneously to an active metabolite and penetrates the blood-brain barrier. It is well tolerated, making it a suitable candidate for combination chemotherapy. Trials to date have focussed on its activity in advanced metastatic melanoma and high-grade malignant glioma. Investigations into other indications, in particular solid tumors with central nervous system metastases, are ongoing. Studies of new drug schedules and of drugs to ameliorate temozolomide resistance offer the prospect of increased efficacy.