Comparison of the ex vivo chemosensitivity of uveal and cutaneous melanoma

Expression Differences in BCL2 Family Members between Uveal and Cutaneous Melanomas Account for Varying Sensitivity to BH3 Mimetics

Uveal melanoma (UM) is a subtype of melanoma. Although they share a melanocytic origin with cutaneous melanoma (CM), patients with UM have few treatment options. BCL2 homologous 3 mimetics are small-molecule drugs that mimic proapoptotic BCL2 family members. We compared BCL2 family member expression between UM and CM using immunoblot and The Cancer Genome Atlas transcriptomic analysis. UM has a unique signature of low BFL1 and high PUMA proteins compared with CM and 30 other cancer types, making them an attractive candidate for BCL2 homologous 3 protein mimetics. We tested the efficacy of a BCL2 inhibitor and MCL1 inhibitor (MCL1i) in UM, with viability assays, live-cell imaging, sphere assays, and mouse xenograft models. UM had a higher sensitivity to MCL1i than CM. Overexpression of BFL1 or knockdown of PUMA made the UM more resistant to MCL1i. In contrast, MAPK/extracellular signal‒regulated kinase inhibitor treatment in CM made them more sensitive to MCL1i. However, MCL1i-alone treatment was not very effective to reduce the UM initiating cells; to overcome this, we employed a combination of MCL1i with BCL2 inhibitor that synergistically inhibited UM initiating cell's capacity to expand. Overall, we identify a distinct expression profile of BCL2 family members for UM that makes them susceptible to BCL2 homologous 3 mimetics.

Systemic and liver-directed therapies in metastatic uveal melanoma: state-of-the-art and novel perspectives

Metastatic uveal melanoma (MUM) is the most common form of noncutaneous melanoma. It is different from its cutaneous counterpart and is characterized by a very poor prognosis. Despite groundbreaking improvements in the treatment of cutaneous melanoma, there have been few advances in the treatment of MUM, and standard treatments for MUM have not been defined. We performed a systematic review focusing our attention on all interventional studies, ongoing or already published, concerning the treatment of MUM. We present results from studies of chemotherapy, targeted therapy, immunotherapy and liver-directed therapies. Although the results in this setting have been disappointing until now, trials investigating novel immunotherapeutic strategies alone and in combination with targeted agents and liver-directed therapies are ongoing.

Infectious Knockdown of CREB and HIF-1 for the Treatment of Metastatic Uveal Melanoma

Uveal melanoma (UM) is the most prevalent primary intraocular cancer in adults. Up to half the patients develop metastases that are currently incurable, and most patients die within two years following the diagnosis of metastases. Therefore, novel therapeutic approaches are required. It has been established that tumor cells are more resistant to the hypoxia cue than non-malignant cells and can remain viable in hypoxia. Oxygen absence in hypoxic tumor areas means the absence of chemotherapeutics and the absence of the effector for radiotherapy (free oxygen radicals). To overcome this treatment resistance, we constructed MuLV-based replication-competent retroviral (RCR) vectors expressing shRNA targeting the hypoxia-response regulating genes CREB and HIF-1. These RCRs express shRNAs either against a single exon or against an exon and the poly-A signal to minimize the point-mutation resistance. These RCRs that only infect replicating cells will preferentially infect tumor cells. Pre-infected Mel270 UM subcutaneous xenografts in SCID mice were monitored weekly in vivo via bioluminescence. Here, we demonstrate that the knockdown of CREB or HIF-1 in UM cells dramatically decreases UM tumor progression. The reduction of the expression of Glut-1, which is a major glucose transporter in cancer cells, within tumors that are infected with the armed viruses may indicate UM's dependence on glycolysis for tumor progression.

A novel combinatorial treatment option for metastatic uveal melanoma

Uveal melanoma (UM) is the most frequent intraocular tumor in adult patients. When metastases occur, systemic therapy with alkylating agents (fotemustine or dacarbazine (DTIC)) has shown only modest efficacy. The common chemotherapeutic drug doxorubicin (DOX) is not used to treat metastatic UM (mUM). To expand the chemotherapeutic arsenal for mUM, we tested the effect of DOX on UM cell mortality. We have previously shown that CREB knockdown enhances sensitivity to DOX. UM cells infected with recombinant MuLV-based replicative competent retroviruses (RCR) expressing shRNA targeting CREB were co-treated with either DTIC or DOX. We found that CREB knockdown increases the sensitivity of these cells to both DOX and DTIC in normoxia and more so in hypoxia as measured by cell survival and Caspase 3 activation. The ability to combine CREB knockdown by infection with the RCR recombinant virus which preferentially infects replicating tumor cells and chemotherapy to achieve the same amount of cell death in lower concentrations may result in fewer side effects of the drugs. This combination is a possible new treatment for mUM.

Ocular disposition of treosulfan and its active epoxy-transformers following intravenous administration in rabbits

Treosulfan (TREO) has an established position in chemotherapy of advanced ovarian cancer but has been also applied in uveal melanoma patients. Moreover, it is used as an orphan drug for a myeloablative conditioning prior to stem cell transplantation. In this paper, biodistribution of prodrug TREO and its active monoepoxide (S,S-EBDM) and diepoxide (S,S-DEB) into aqueous humor of the eye was studied for the first time. For that purpose, alone TREO and the mixture of TREO, S,S-EBDM and S,S-DEB were administered intravenously to New Zealand White rabbits. The three analytes were determined in plasma and aqueous humor by validated HPLC methods and pharmacokinetic calculations were performed in WinNonlin. After the infusion of TREO, the aqueous humor/plasma C_max ratio and area under the curve ratio amounted 0.04 and 0.10 for TREO, and 1.1 and 2.2 for S,S-EBDM, respectively. Following the bolus injection of the mixture of the prodrug and its epoxides, the aqueous humor/plasma C_max ratios for TREO, S,S-EBDM and S,S-DEB were 0.05, 0.66, and 4.0, respectively. The presented results indicate a poor penetration of TREO into the eye, which may impair systemic treatment of ocular tumors but is beneficial in terms of a lack of clinically relevant ophthalmic adverse effects.

Designing personalised cancer treatments

The concept of personalised medicine for cancer is not new. It arguably began with the attempts by Salmon and Hamburger to produce a viable cellular chemosensitivity assay in the 1970s, and continues to this day. While clonogenic assays soon fell out of favour due to their high failure rate, other cellular assays fared better and although they have not entered widespread clinical practice, they have proved to be very useful research tools. For instance, the ATP-based chemosensitivity assay was developed in the early 1990s and is highly standardised. It has proved useful for evaluating new drugs and combinations, and in recent years has been used to understand the molecular basis of drug resistance and sensitivity to anti-cancer drugs. Recent developments allow unparalleled genotyping and phenotyping of tumours, providing a plethora of targets for the development of new cancer treatments. However, validation of such targets and new agents to permit translation to the clinic remains difficult. There has been one major disappointment in that cell lines, though useful, do not often reflect the behaviour of their parent cancers with sufficient fidelity to be useful. Low passage cell lines - either in culture or xenografts are being used to overcome some of these issues, but have several problems of their own. Primary cell culture remains useful, but large tumours are likely to receive neo-adjuvant treatment before removal and that limits the tumour types that can be studied. The development of new treatments remains difficult and prediction of the clinical efficacy of new treatments from pre-clinical data is as hard as ever. One lesson has certainly been that one cannot buck the biology - and that understanding the genome alone is not sufficient to guarantee success. Nowhere has this been more evident than in the development of EGFR inhibitors. Despite overexpression of EGFR by many tumour types, only those with activating EGFR mutations and an inability to circumvent EGFR blockade have proved susceptible to treatment. The challenge is how to use advanced molecular understanding with limited cellular assay information to improve both drug development and the design of companion diagnostics to guide their use. This has the capacity to remove much of the guesswork from the process and should improve success rates.

Phase II trial of sorafenib in combination with carboplatin and paclitaxel in patients with metastatic uveal melanoma: SWOG S0512

BACKGROUND

Sorafenib, a multikinase inhibitor of cell proliferation and angiogenesis, inhibits the mitogen-activated protein kinase pathway that is activated in most uveal melanoma tumors. This phase II study was conducted by the SWOG cooperative group to evaluate the efficacy of sorafenib in combination with carboplatin and paclitaxel (CP) in metastatic uveal melanoma.

METHODS

Twenty-five patients with stage IV uveal melanoma who had received 0-1 prior systemic therapy were enrolled. Treatment included up to 6 cycles of carboplatin (AUC = 6) and paclitaxel (225 mg/m(2)) administered IV on day 1 plus sorafenib (400 mg PO twice daily), followed by sorafenib monotherapy until disease progression. The primary endpoint was objective response rate (ORR); a two-stage design was used with the study to be terminated if no confirmed responses were observed in the first 20 evaluable patients. Secondary efficacy endpoints included progression-free survival (PFS) and overall survival (OS).

RESULTS

No confirmed objective responses occurred among the 24 evaluable patients (ORR = 0% [95% CI: 0-14%]) and the study was terminated at the first stage. Minor responses (tumor regression less than 30%) were seen in eleven of 24 (45%) patients. The median PFS was 4 months [95% CI: 1-6 months] and the 6-month PFS was 29% [95% CI: 13%-48%]. The median OS was 11 months [95% CI: 7-14 months].

CONCLUSION

In this study, the overall efficacy of CP plus sorafenib in metastatic uveal melanoma did not warrant further clinical testing when assessed by ORR, although minor tumor responses and stable disease were observed in some patients.

TRIAL REGISTRATION

ClinicalTrials.govNCT00329641.

The effect of tricyclic antidepressants on cutaneous melanoma cell lines and primary cell cultures

The tricyclic antidepressants have previously been shown to exert activity against glioma cells in vitro. Initial studies in cell lines suggested that this might extend to melanoma cells. We have therefore conducted a study in primary cell cultures from metastatic cutaneous melanoma deposits using a well established ATP-based tumour chemosensitivity assay to confirm and extend these findings. Two cell lines and eight primary cell cultures from metastatic melanoma deposits were exposed to three tricyclic drugs, amitriptyline, nortriptyline and clomipramine, at concentrations ranging from 200 to 6.25 µmol/l in the ATP-based tumour chemosensitivity assay. All three drugs showed activity, although nortriptyline was more active than clomipramine or amitriptyline in both cell lines and primary cell cultures, with an IC50 of 9, 27 and 33 µmol/l, respectively. Tricyclic agents show activity against melanoma in vitro. This could be related to the lysosomal effects based on their cationic amphiphilic properties, or effects at the mitochondrial membrane.

Phase II clinical trial evaluating docetaxel, vinorelbine and GM-CSF in stage IV melanoma

Purpose

Metastatic melanoma patients have a poor prognosis. No chemotherapy regimen has improved overall survival. More effective treatments are needed. Docetaxel has clinical activity in melanoma and may be more active when combined with vinorelbine. Granulocyte–macrophage colony-stimulating factor (GM-CSF) has shown activity as an adjuvant melanoma therapy. We carried out a phase II study of these agents in patients with stage IV melanoma.

Methods

Patients had documented stage IV melanoma and may have had prior immuno or chemotherapy. Previously treated brain metastases were allowed. Docetaxel (40 mg/m² IV) and vinorelbine (30 mg/m² IV) were administered every 14 days, followed by GM-CSF (250 mg/m2 SC on days 2 to 12). The primary endpoint of the study was 1-year overall survival (OS). Secondary objectives were median overall survival, response rate (per RECIST criteria), and the toxicity profiles.

Results

Fifty-two patients were enrolled; 80% had stage M1c disease. Brain metastases were present in 21%. Fifty-two percent of patients had received prior chemotherapy, including 35% who received prior biochemotherapy. Toxicity was manageable. Grade III/IV toxicities included neutropenia (31%), anemia (14%), febrile neutropenia (11.5%), and thrombocytopenia (9%). DVS chemotherapy demonstrated clinical activity, with a partial response in 15%, and disease stabilization in 37%. Six-month PFS was 37%. Median OS was 11.4 months and 1-year OS rate was 48.1%.

Conclusions

The DVS regimen was active in patients with advanced, previously treated melanoma, with manageable toxicity. The favorable 1-year overall survival and median survival rates suggest that further evaluation of the DVS regimen is warranted.

Resistance of uveal melanoma to the interstrand cross-linking agent mitomycin C is associated with reduced expression of CYP450R

BACKGROUND

Uveal melanoma (UM) is the most common primary intraocular tumour of adults, frequently metastasising to the liver. Hepatic metastases are difficult to treat and are mainly unresponsive to chemotherapy. To investigate why UM are so chemo-resistant we explored the effect of interstrand cross-linking agents mitomycin C (MMC) and cisplatin in comparison with hydroxyurea (HU).

METHODS

Sensitivity to MMC, cisplatin and HU was tested in established UM cell lines using clonogenic assays. The response of UM to MMC was confirmed in MTT assays using short-term cultures of primary UM. The expression of cytochrome P450 reductase (CYP450R) was analysed by western blotting, and DNA cross-linking was assessed using COMET analysis supported by γ-H2AX foci formation.

RESULTS

Both established cell lines and primary cultures of UM were resistant to the cross-linking agent MMC (in each case P<0.001 in Student's t-test compared with controls). In two established UM cell lines, DNA cross-link damage was not induced by MMC (in both cases P<0.05 in Students's t-test compared with damage induced in controls). In all, 6 out of 6 UMs tested displayed reduced expression of the metabolising enzyme CYP450R and transient expression of CYP450R increased MMC sensitivity of UM.

CONCLUSION

We suggest that reduced expression of CYP450R is responsible for MMC resistance of UM, through a lack of bioactivation, which can be reversed by complementing UM cell lines with CYP450R.

In vitro adenosine triphosphate based chemotherapy response assay in gastric cancer

Purpose

The purpose of this study was to investigate the reliability and the clinical applicability of the adenosine-triphosphate-based chemotherapy response assay (ATP-CRA) as a method of determining in vitro chemosensitivity in patients with gastric cancer.

Materials and Methods

A total of 243 gastric cancer tissue samples were obtained from gastrectomies performed between February 2007 and January 2010. We evaluated the effectiveness of the ATP-CRA assay in determining the chemosensitivity of gastric cancer specimens using eleven chemotherapeutic agents - etoposide, doxorubicin, epirubicin, mytomicin, 5-fluorouracil, oxaliplatin, irinotecan, docetaxel, paclitaxel, methotraxate, and cisplatin - for chemosensitivity studies using ATP-CRA. We assessed the failure rate, the cell death rate, and the chemosensitivity index.

Results

The failure rate of ATP-CRA was 1.6% (4/243). The mean coefficient of variation for triplicate ATP measurements was 6.5%. Etoposide showed the highest cell death rate (35.9%) while methotrexate showed the lowest (16.6%). The most active chemotherapeutic agent was etoposide, which most frequently ranked highest in the chemosensitivity test: 31.9% (51/160). Oxaliplatin was more active against early gastric cancers than advanced gastric cancers, whereas docetaxel was more active against advanced cancers. The lymph node negative group showed a significantly higher cell death rate than the lymph node positive group when treated with doxorubicin, epirubicin, and mitomycin.

Conclusions

ATP-CRA is a stable and clinically applicable in vitro chemosensitivity test with a low failure rate. The clinical usefulness of ATP-CRA should be evaluated by prospective studies comparing the regimen guided by ATP-CRA with an empirical regimen.

A pilot study with vincristine sulfate liposome infusion in patients with metastatic melanoma

Vincristine sulfate liposome infusion (VSLI) is a sphingomyelin/cholesterol liposome encapsulated formulation of vincristine that results in an extended drug circulation time and the potential for enhanced malignancy targeting, exposure, and anticancer activity. We assessed the safety and activity of VSLI in patients with metastatic melanoma. VSLI, to provide VCR 2.0 mg/m without dose capping, was infused over 1 h every 2 weeks (one cycle). Safety, tumor response, and survival were determined. Twenty-seven patients with metastatic melanoma of cutaneous (n=19), uveal (n=4), mucosal (n=1), and unknown (n=3) primary were treated. Twenty-five (93%) patients had received one or more prior lines of chemotherapy and/or immunotherapy; 14 (48%) had received a vinblastine-containing regimen. Hematologic adverse events (AEs) primarily manifested as grade 1/2 neutropenia. Nonhematologic AEs primarily consisted of gastrointestinal and constitutional symptoms of grade 1/2 severity. Grade 3 AEs included one case of paresthesia and four cases of constipation. The disease control rate in 26 evaluable patients was 31%. One complete (uveal melanoma metastatic to lung) and two partial responses (previously untreated cutaneous melanoma metastatic to the bone, brain, spleen and lung, and another with melanoma of unknown primary involving the lung, liver, and lymph node) were found. Five patients had stable disease. The median time to progression was 1.9 months. The median survival was 9.6 months with 30% of the patients alive at 1 year. VSLI was generally well tolerated and showed promising antitumor activity against metastatic melanoma and uveal melanoma in particular. A phase 2 trial to further elucidate the efficacy and safety of VSLI in metastatic uveal melanoma is ongoing.

Uveal vs. cutaneous melanoma. Origins and causes of the differences

Melanoma is a malignant tumour derived from melanocytes (dendritic cells originated from the neural crest and capable to produce melanin synthesis) that could be established on the skin or less frequently on the uvea. The cellular origin from both kind of melanoma seems to be the same but the melanocytes migrates to the epithelia for cutaneous melanoma, while for uveal melanoma, they migrate to mesodermic tissues. Despite the common origin, both melanomas show extreme differences in their metastatic potential, clinical response to treatments, immune response and genetic alterations. We will describe some of those differences in this review.

Cisplatin, gemcitabine and treosulfan is effective in chemotherapy-pretreated relapsed stage IV uveal melanoma patients

PURPOSE

The efficacy of cisplatin, gemcitabine, and treosulfan (CGT) was evaluated in patients with chemotherapy pretreated relapsed AJCC stage IV uveal malignant melanoma.

METHODS

Patients received i.v./intrahepatic cisplatin, i.v. gemcitabine, and i.v. treosulfan (CGT) on day 1 and 8 as first-line (n = 1), second-line (n = 9), third-line (n = 1) or fourth-line (n = 1) therapy. Cisplatin, gemcitabine, and treosulfan (CGT)-therapy was repeated every 5 weeks until progression of disease occurred. A maximum of six CGT-cycles (mean, 2 cycles) was administered per patient.

RESULTS

No objective response was observed, six patients (50%) had stable disease and six (50%) patients progressed upon first reevaluation. Overall survival of all the 12 patients was 6 months. Patients with stable disease reached a median overall survival of 12 months, while patients with disease progression upon first reevaluation had a median overall survival of 4 months, only. Grade III/IV related hematotological side effects were experienced in six (leukopenia) and four (thrombocytopenia) patients.

CONCLUSIONS

Treatment with CGT may lead to disease stabilization and prolonged survival in a substantial proportion of progressive stage IV uveal melanoma patients, even following heavy chemotherapy treatment.

A prospective single arm phase II study of dacarbazine and treosulfan as first-line therapy in metastatic uveal melanoma

Uveal melanoma is relatively uncommon accounting for fewer than 5% of all melanoma cases. Localized tumours are curable by local therapy but a significant percentage of patients go on to have a relapse with metastatic disease. Uncertainty remains concerning the level of activity of dacarbazine in uveal melanoma as opposed to that in the cutaneous form. Recently, a possible role for treosulfan in uveal disease has been reported. A phase II study was therefore undertaken to assess the objective response rate of the combination of dacarbazine and treosulfan in previously untreated patients with metastatic uveal melanoma. All patients received dacarbazine 850 mg/m and treosulfan 8 g/m(2) every 21 days up to a maximum of six cycles. Fifteen patients enrolled in the study. As expected, the major toxicities were haematological (particularly thrombocytopaenia) but the treatment was generally well tolerated. No responses were seen; however, disease stabilization was achieved in two patients. Median progression free survival from the start of chemotherapy was 12 weeks and median overall survival was 30 weeks. This study, using the combination of dacarbazine and treosulfan, while well tolerated, did not confirm earlier reports suggesting treosulfan is active in uveal melanoma.

The effect of imatinib mesylate (Glivec) on human tumor-derived cells

Imatinib mesylate is a specific inhibitor of the Bcr-Abl protein tyrosine kinase that competes with ATP for its specific binding site in the kinase domain. It has activity against platelet-derived growth factor receptor alpha and beta (PDGFR-alpha and -beta), and c-kit, the receptor for stem cell factor. We have used a standardized ATP-tumor chemosensitivity assay and immunohistochemistry to determine the cytotoxicity of imatinib mesylate in tumor-derived cells from cutaneous and uveal melanoma, and ovarian carcinoma. Imatinib mesylate was tested at concentrations ranging from 2.0 to 0.0625 micromol/l alone and in combination with a cytotoxic drug (cisplatin, doxorubicin, paclitaxel or treosulfan). Imatinib mesylate showed low inhibition (IndexSUM>300) across the range of concentrations tested in this study, with few tumors exhibiting increasing inhibition with increased drug concentration. The median IC90 values for cutaneous and uveal melanoma and ovarian carcinoma were 13.2 micromol/l (4.0-294.3 micromol/l), 12.0 micromol/l (2.0-285.4 micromol/l) and 7.71 micromol/l (6.51-11.02 micromol/l), respectively. Imatinib mesylate potentiated the effect of different cytotoxics in 9% (5/54) of cases and had a negative effect in 13% (7/54) of cases, with no effect in the remainder. No correlation of effect was noted with c-kit, platelet-derived growth factor receptor-alpha or platelet-derived growth factor receptor-beta expression, assessed by immunohistochemistry. The signaling pathways mediated by activation of c-kit or platelet-derived growth factor receptor may act as antiapoptotic survival signals in some cancers and inhibition of these pathways may potentiate the activity of some cytotoxic drugs by inhibiting the survival signal. Growth inhibition, however, may reduce the efficacy of cytotoxic drugs, which tend to target proliferating cells preferentially, and clinical effects are therefore difficult to predict.

A phase II study of bendamustine chemotherapy as second-line treatment in metastatic uveal melanoma

Uveal melanoma is the most frequent primary malignant neoplasm of the eye and has a poor prognosis in metastatic stage. Fotemustine or a combination of gemcitabine and treosulfan has demonstrated some efficacy in metastatic disease. We conducted a phase II trial to assess the second-line activity and toxicity of bendamustine hydrochloride, a nucleoside analogue with alkylating activity. Inclusion criteria were a Karnofsky performance status of > or = 60% and progressive disease during or after first-line chemotherapy. Bendamustine was administered at a dose of 120 mg/m2 on days 1 and 2. Cycles were repeated on day 22. The primary endpoint of the study was the determination of the number of patients achieving an objective response or stable disease. The secondary endpoint was toxicity. Eleven patients were enrolled into the trial. Grade III and IV toxicity consisted of anaemia, thrombocytopenia and leucocytopenia in two, one and two patients, respectively. No grade III or IV non-haematological toxicity was observed. According to Response Evaluation Criteria in Solid Tumours (RECIST), all patients showed progressive disease. We conclude that bendamustine is ineffective as second-line chemotherapy for metastatic uveal melanoma.

Cytotoxic effects of violacein in human uveal melanoma cell lines

Violacein is the main pigment produced by Chromobacterium violaceum, a saprophytic gram-negative bacillus. Violacein is formed by the condensation of two modified tryptophan molecules and has potential anti-neoplastic effects. The purpose of this pilot study was to investigate the in vitro activity of violacein in human uveal melanoma cell lines. Human uveal melanoma cell lines 92.1 and OCM-1 were incubated with five different concentrations of violacein (10(-5)-10(-9) M), and the total cellular protein content was measured by means of the sulphorhodamine B assay. Dose-response curves were obtained and the concentration inhibiting cell growth by 50% (IC50) together with the concentration inhibiting the net cell growth by 50% (GI50) were calculated for both cell lines. Violacein IC50 and GI50 concentrations to cell line 92.1 were 2.78 x 10(-6) M and 1.69 x 10(-6) M, respectively. The IC50 and GI50 concentrations to cell line OCM-1 were 3.69 x 10(-6) M and 2.12 x 10(-6) M, respectively. Previous studies using the same methodology have revealed violacein to have a GI50 in the range (3-6) x 10(-8) M for MOLT-4 leukaemia, NCI-H460 large cell lung cancer and KM12 colon cancer cell lines. Violacein displayed borderline cytotoxic activity in human uveal melanoma cell lines 92.1 and OCM-1, as measured by the sulphorhodamine B assay, and further studies are necessary to define its suitability as a potential therapeutic agent for metastatic uveal melanoma.

Clinical evaluation of in vitro chemosensitivity testing: the example of uveal melanoma

PURPOSE

Results from in vitro chemosensitivity testing recommend treosulfan/gemcitabine chemotherapy for the treatment of stage IV uveal melanoma.

METHODS

Twenty patients received treosulfan 3,500 mg/m2 followed by gemcitabine 1,000 mg/m2 on day 1 and day 8 repeated on day 29. In cases of prior chemotherapy only 75% of these dosages were used.

RESULTS

Without any patient achieving an objective response, 25% of patients (95% confidence interval, 8.6-49.1%) had stabilisation of disease. This stabilisation was associated with a prolonged median overall survival of 17 months compared with 7 months for the patients with progressive disease. First-line treatment was not associated with better response or survival although prognostic parameters did not significantly differ from that of other patients.

CONCLUSIONS

The results are disappointing and question the value of individualized chemotherapy based on in vitro assays.

Developments in the management of uveal melanoma

Uveal melanomas threaten visual loss, enucleation, and death from metastatic disease. Most patients present because of symptoms, but failures of detection and diagnosis still occur commonly. Treatments aimed at avoiding enucleation include: plaque, proton beam or stereotactic radiotherapy; trans-scleral or trans-retinal local resection; and transpupillary thermotherapy. Increasingly, different modalities are being used in combination. The ocular outcomes are related to tumour size, location, spread and cell type. Metastatic disease occurs in many patients and is related to factors such as tumour dimensions, ciliary body involvement, cell type, extravascular matrix patterns and cytogenetics. Abnormalities related to chromosomes 3, 6 and 8 are strongly related to tumour behaviour, for the first time enabling survival probability to be estimated with a high degree of reliability in an individual patient. This enables high-risk individuals to be targeted for screening while providing reassurance to those with a minimal chance of developing metastatic disease. Such targeting would allow selection of patients for adjuvant systemic therapy, should a suitable treatment become available, and would also facilitate the evaluation of such treatment by increasing the statistical power of any randomized prospective study. The high mortality in patients with monosomy 3 melanoma suggests that in these patients ocular treatment is only palliative. Cytogenetic studies suggest that some melanomas may never develop any metastatic potential and if these impressions are confirmed by further studies, then in these patients the main priority of treatment would be to conserve vision.

The in vitro effect of gefitinib ('Iressa') alone and in combination with cytotoxic chemotherapy on human solid tumours

BACKGROUND

Activation of the epidermal growth factor receptor (EGFR) triggers downstream signaling pathways that regulate many cellular processes involved in tumour survival and growth. Gefitinib ('Iressa') is an orally active tyrosine kinase inhibitor (TKI) targeted to the ATP-binding domain of EGFR (HER1; erbB1).

METHODS

In this study we have used a standardised ATP-based tumour chemosensitivity assay (ATP-TCA) to measure the activity of gefitinib alone or in combination with different cytotoxic drugs (cisplatin, gemcitabine, oxaliplatin and treosulfan) against a variety of solid tumours (n = 86), including breast, colorectal, oesophageal and ovarian cancer, carcinoma of unknown primary site, cutaneous and uveal melanoma, non-small cell lung cancer (NSCLC) and sarcoma. The IC50 and IC90 were calculated for each single agent or combination. To allow comparison between samples the IndexSUM was calculated based on the percentage tumour growth inhibition (TGI) at each test drug concentration (TDC). Gefitinib was tested at concentrations ranging from 0.0625-2 microM (TDC = 0.446 microg/ml). This study represents the first use of a TKI in the assay.

RESULTS

There was heterogeneity in the degree of TGI observed when tumours were tested against single agent gefitinib. 7% (6/86) of tumours exhibited considerable inhibition, but most showed a more modest response resulting in a low TGI. The median IC50 value for single agent gefitinib in all tumours tested was 3.98 microM. Interestingly, gefitinib had both positive and negative effects when used in combination with different cytotoxics. In 59% (45/76) of tumours tested, the addition of gefitinib appeared to potentiate the effect of the cytotoxic agent or combination (of these, 11% (5/45) had a >50% decrease in their IndexSUM). In 38% of tumours (29/76), the TGI was decreased when the combination of gefitinib + cytotoxic was used in comparison to the cytotoxic alone. In the remaining 3% (2/76) there was no change observed.

CONCLUSION

The in vitro model suggests that gefitinib may have differential effects in response to concomitant cytotoxic chemotherapy with the agents tested during this study. The mechanism involved may relate to the effect of TKIs on growth rate versus their effect on the ability of the cell to survive the stimulus to apoptosis produced by chemotherapy.

Treatment options for choroidal malignant melanoma: a case report featuring transpupillary thermotherapy

BACKGROUND

Choroidal melanoma is the most common primary ocular tumor in adults. These tumors are almost always unilateral and develop spontaneously or arise from pre-existing nevi. Historically, treatment for choroidal melanoma was enucleation. New therapies have been developed to treat choroidal melanoma and to preserve the eye. Currently, these treatment options include brachytherapy and transpupillary thermotherapy.

CASE REPORT

A 51-year-old man came to the eye clinic with symptoms of mildly decreased fluctuating vision and floaters with no flashes in the temporal visual field of the right eye. Best-corrected visual acuities were 20/30 O.D. and 20/20 O.S. A small-to-medium choroidal lesion was found in the right eye. Ultrasonography and A-scan showed this lesion to be a choroidal malignant melanoma. The patient's surgical options included enucleation, brachytherapy, and transpupillary thermotherapy. The patient opted to have transpupillary thermotherapy to preserve the eye, and subsequently underwent two procedures that eventually obliterated the melanoma, resulting in best-corrected visual acuity of 20/40.

CONCLUSION

Transpupillary thermotherapy is an excellent option for treatment of small-to-medium choroidal melanomas. Brachytherapy is also an option for treatment, but with increased ocular side effects and complications. Enucleation is still commonly performed on medium and/or large choroidal melanomas.

Chemosensitivity testing as an aid to anti-cancer drug and regimen development

The ATP-based chemosensitivity assay has proved particularly useful for the evaluation of new anti-cancer agents and combinations. The majority of our publications in this area have concentrated on topoisomerase inhibitors. Comparison of mitoxantrone with doxorubicin convinced us that these two agents were not completely cross-resistant and led to the design of the mitoxantrone + paclitaxel regimen which is now in clinical practice. Re-assessment of treosulfan in uveal melanoma led to the design of a new regimen combining this alkylating agent with gemcitabine, again with rapid introduction of this combination to clinical practice. The assay has recently been used to examine the concentration-activity curve to determine which tumours might benefit from liposomal preparations capable of delivering 4-16 times the standard dose without cardiotoxicity. Assay-directed use of Caelyx is producing encouraging results, and we are now examining this drug in combination with others. We recently showed that XR5000, a combined inhibitor of topoisomerase I and II, was effective against melanoma as well as ovarian cancer, but at concentrations which were unlikely to be achieved in patients. These data confirm our suggestion that use of the assay could reduce the time to introduction of new anti-cancer drugs and the cost of this process.

Treosulfan and gemcitabine in metastatic uveal melanoma patients: results of a multicenter feasibility study

No effective treatment currently exists for metastatic uveal melanoma. However, recent results obtained by an ATP-based tumor chemosensitivity assay have shown consistent activity of treosulfan+gemcitabine in up to 80% of tumor specimens tested. In this study we describe the first clinical results observed with this drug combination at different European centers in patients with metastatic uveal melanoma. Clinical case series of patients with metastatic uveal melanoma were treated with treosulfan+gemcitabine at seven different centers. Fourteen patients, 13 previously untreated and one pretreated with chemoimmunotherapy, were included in the study. Patients received treosulfan+gemcitabine in four different dose regimens. The response rates, progression-free and overall survival, and toxicity were evaluated. The analysis of 14 patients revealed one complete response, three partial responses and a stable disease in eight cases. The objective response rate was 28.6%, the median overall survival was 61 weeks [95% confidence interval (CI) 54-133 weeks], the progression-free survival was 28.5 weeks (95% CI 13-62 weeks) and the 1-year survival rate was 80%. The drugs were well tolerated. The most common side-effects were leuko- and thrombocytopenia. These preliminary results suggest potential therapeutic benefit of treosulfan+gemcitabine treatment in metastatic uveal melanoma and warrant further controlled studies.

Bleomycin, vincristine, lomustine and dacarbazine (BOLD) in combination with recombinant interferon alpha-2b for metastatic uveal melanoma

This EORTC multicentre study analysed the efficacy and tolerability in patients with metastatic uveal melanoma of BOLD chemotherapy in combination with recombinant interferon alpha-2b. The dose of bleomycin was 15 mg on days 2 and 5, of vincristine 1 mg/m(2) on days 1 and 4, of lomustine 80 mg on day 1, and of dacarbazine (DTIC) 200 mg/m(2) on days 1-5, given every 4 weeks for a minimum of two cycles. Subcutaneous (s.c.) interferon alpha-2b at a dose of 3 x 10(6) IU was initiated on day 8 of the first cycle, and continued at a dose of 6 x 10(6) IU three times per week after 6 weeks. A median of two cycles were administered to 24 patients (median age 60.5 years). None achieved an objective response (0%; 95% Confidence Interval (CI): 0-14), 2 (8.3%) remained stable, 20 showed progression, and 2 (8.3%) were invaluable. The median progression-free survival was 1.9 months (95% CI: 1.8-3.4) and overall survival 10.6 months (95% CI: 6.9-16.4). Overall survival improved with increasingly favourable pretreatment characteristics (median, 14.7 versus 6.9 versus 6.0 months for Helsinki University Central Hospital (HUCH) Working Formulation stages IVBa, IVBb and IVBc, respectively; P=0.018). Grade 3 alopecia and neurotoxicity occurred in 13% of the patients. This multicentre study did not confirm earlier reports that BOLD with human leucocyte or recombinant interferon would induce at least 15% objective responses in metastatic uveal melanoma.

Chemosensitivity of normal human trophoblasts evaluated by a newly developed ATP-based luminescence assay

Trophoblast injury may be one of the possible causes of fetal distress associated with chemotherapy administered during pregnancy. The purpose of this study was to investigate the ex vivo chemosensitivity of normal trophoblasts (NTB) against commonly used antineoplastic agents. Using the newly developed ex vivo ATP-based trophoblast assay (ATP-TBA), 31 NTB freshly sampled from human placentas (gestational week 7-42) were tested against dactinomycin (Act-D), 5-fluorouracil (5-FU), 4-OOH-cyclophosphamide (4-HC), vincristine (VCR) and methotrexate (MTX) alone or in combination with calcium folate (LV). All agents were studied at concentrations relevant to clinical dosages normally used for chemotherapy of solid neoplasms. Of 31 samples studied with the ATP-TBA, 20 (65%) were evaluable. VCR, Act-D and 4-HC were the most active drugs with 55, 45 and 45% of samples responding ex vivo. Antimetabolites were less active, producing ex vivo response rates of 25 (MTX) and 20% (5-FU), respectively. MTX activity was largely neutralized by adding LV. The chemosensitivity of NTB showed considerable inter-individual variations and did not decrease with increasing gestational age. We therefore conclude that NTB of any gestational age exhibit considerable ex vivo sensitivity against common anticancer agents which is comparable to that observed for various solid tumors. The ATP-TBA may be helpful in planning future trials with both single agents and drug combinations in order to standardize and optimize chemotherapy during pregnancy.