Carboplatin dosage: prospective evaluation of a simple formula based on renal function

A dosage formula has been derived from a retrospective analysis of carboplatin pharmacokinetics in 18 patients with pretreatment glomerular filtration rates (GFR) in the range of 33 to 136 mL/min. Carboplatin plasma clearance was linearly related to GFR (r = 0.85, P less than .00001) and rearrangements of the equation describing the correlation gave the dosage formula dose (mg) = target area under the free carboplatin plasma concentration versus time curve (AUC) x (1.2 x GFR + 20). In a prospective clinical and pharmacokinetic study the formula was used to determine the dose required to treat 31 patients (GFR range, 33 to 135 mL/min) with 40 courses of carboplatin. The target AUC was escalated from 3 to 8 mg carboplatin/mL/min. Over this AUC range the formula accurately predicted the observed AUC (observed/predicted ratio 1.24 +/- 0.11, r = 0.886) and using these additional data, the formula was refined. Dose (mg) = target AUC x (GFR + 25) is now the recommended formula. AUC values of 4 to 6 and 6 to 8 mg/mL. min gave rise to manageable hematological toxicity in previously treated and untreated patients, respectively, and hence target AUC values of 5 and 7 mg/mL min are recommended for single-agent carboplatin in these patient groups. Pharmacokinetic modeling demonstrated that the formula was reasonably accurate regardless of whether a one- or two-compartment model most accurately described carboplatin pharmacokinetics, assuming that body size did not influence nonrenal clearance. The validity of this assumption was demonstrated in 13 patients where no correlation between surface area and nonrenal clearance was found (r = .31, P = .30). Therefore, the formula provides a simple and consistent method of determining carboplatin dose in adults. Since the measure of carboplatin exposure in the formula is AUC, and not toxicity, it will not be influenced by previous or concurrent myelosuppressive therapy or supportive measures. The formula is therefore applicable to combination and high-dose studies as well as conventional single-agent therapy, although the target AUC for carboplatin will need to be redefined for combination chemotherapy.

The assessment of antiangiogenic and antivascular therapies in early-stage clinical trials using magnetic resonance imaging: issues and recommendations

Vascular and angiogenic processes provide an important target for novel cancer therapeutics. Dynamic contrast-enhanced magnetic resonance imaging is being used increasingly to noninvasively monitor the action of these therapeutics in early-stage clinical trials. This publication reports the outcome of a workshop that considered the methodology and design of magnetic resonance studies, recommending how this new tool might best be used.

Synovial sarcoma: a clinicopathologic, staging, and prognostic assessment

PURPOSE

Synovial sarcoma (SS) is a common soft tissue sarcoma (STS) with a propensity for young adults and notable sensitivity to chemotherapy (CT). This study provides a current clinicopathologic, staging, and prognostic assessment for SS. The problems with the current American Joint Committee for Cancer (AJCC) Staging System in relation to SS are discussed.

METHODS

Review of a prospective database supplemented by retrospective data.

RESULTS

One hundred fifty patients were assessed; median age was 30 years and median follow-up was 52 months. Overall actuarial 5-year survival rate was 57%. Size trend, but not a cutoff of less than 5 cm versus > or = 5 cm, was a prognostic indicator (P <.001). The current AJCC/International Union Against Cancer Staging System differentiated prognosis less well than the recently proposed Royal Marsden Hospital Staging System. Age greater than 20 years at diagnosis implied worse prognosis. A local recurrence event was associated with a worse survival (P <.001). Therapeutic CT was administered to 55 patients. Eleven of 19 patients had an objective response to a combination of ifosfamide and doxorubicin. Four cases had complete response after CT. Twenty-one patients had pulmonary metastasectomy, with an actuarial 5-year survival rate of 23%.

CONCLUSION

SS tends to affect young people. In this subtype of STS, size trend is the most significant influence on stage and hence survival; however, smaller SSs have an unexpectedly poor prognosis. Adequate local control may affect survival. SS is often chemosensitive, and given its poor prognosis, multicenter trials of adjuvant therapy are warranted.

Prognostic factors in advanced synovial sarcoma: an analysis of 104 patients treated at the Royal Marsden Hospital

AIMS

Key prognostic factors at diagnosis of synovial sarcoma are well defined from the literature. There are few data regarding prognostic parameters in the setting of advanced disease. Our aim was to look specifically at a cohort of patients with advanced synovial sarcoma and to identify potential prognostic factors.

PATIENTS AND METHODS

One hundred and four patients with advanced synovial sarcoma were identified from the Royal Marsden Hospital's sarcoma database between 1978 and 2003. Patient data were analysed retrospectively. Most patients were aged between 20 and 50 years at diagnosis. Seventy-one patients were deceased at the time of analysis. Ninety-two patients received chemotherapy for management of advanced disease (most commonly doxorubicin + ifosfamide).

RESULTS

Median survival following development of advanced disease was 22 months. Predictors of survival with advanced disease were age <35 years (P = 0.03) and response to first-line chemotherapy (P = 0.05). The response rate to doxorubicin plus ifosfamide was 58.6%, and this was superior to either agent when given singly. Metastasectomy was not associated with improved prognosis in this series.

CONCLUSIONS

Synovial sarcoma is a chemosensitive soft tissue sarcoma. Compared with historical controls, survival with advanced disease seems to have improved over the years, possibly as a result of better use of chemotherapy. Age <35 years and response to first-line chemotherapy predict for improved survival with advanced disease.

Measurement of the extracellular pH of solid tumours in mice by magnetic resonance spectroscopy: a comparison of exogenous (19)F and (31)P probes

Precise measurement of pH(e) in vivo may be of clinical value for both diagnosis and selection of therapy. pH(e) measurements made by the (31)P probe 3-aminopropylphosphonate (3-APP) were compared with those made by the (19)F probe, 3-[N-(4-fluor-2-trifluoromethylphenyl)-sulphamoyl]-propionic acid (ZK-150471) in three solid tumour types, human HT29 xenografts, murine RIF-1 fibrosarcomas and Lettre tumours grown subcutaneously in mice. No significant differences were observed when probe measurements of pH(e) were compared at 20-60 min post-administration, although very low pH(e) values (ca. 6.0) were recorded in two out of eight Lettre tumours by ZK-150471. The more rapid pH(e) measurements possible using ZK-150471 showed that during the first 20 min post-administration significant increases occurred in pH(e) which were greatest in the more necrotic tumours. Since isolated cell experiments showed that ZK-150471 was non-toxic and did not enter the cells, this early increase in pH(e) may reflect gradual penetration by ZK-150471 of the reportedly alkaline necrotic space in the tumours. The wide chemical shift range, improved signal-to-noise and absence of signal overlap allowed a more rapid and precise measurement of pH(e) by ZK-150471 compared to 3-APP. These characteristics suggest that ZK-150471 is currently the preferred pH(e) probe for non-invasive MRS.

Intensive treatment of multiple myeloma and criteria for complete remission

50 previously untreated patients with multiple myeloma received two-phase treatment: repeated cycles of 4 day infusion with vincristine, doxorubicin, and methylprednisolone (VAMP) followed by high-dose melphalan (HDM), with autologous bone marrow transplantation where possible. The overall response rate was 74% (37/50), with 25 patients (50%) achieving complete haematological and biochemical remission. These remissions were associated with a good quality of life as measured by performance status, pain grade, and the reversal of humoral immunosuppression. 6 patients died during the VAMP phase and there was 1 death related to HDM. The achievement of complete remission, as defined here, in such a high proportion of patients is exceptional and may represent a useful advance in the management of myeloma.

Randomized phase II study of docetaxel versus doxorubicin in first- and second-line chemotherapy for locally advanced or metastatic soft tissue sarcomas in adults: a study of the european organization for research and treatment of cancer soft tissue and bone sarcoma group

PURPOSE

To assess antitumor response and time to progression (TTP) with docetaxel compared with doxorubicin in first-line treatment of advanced and/or metastatic soft tissue sarcoma.

PATIENTS AND METHODS

Patients with measurable soft tissue sarcoma lesions and adequate bone marrow, liver, and renal function were entered onto the study. They were randomized to either docetaxel 100 mg/m(2) given as a 1-hour intravenous infusion every 3 weeks or doxorubicin 75 mg/m(2) given as a bolus injection every 3 weeks. A maximum of seven cycles of treatment were scheduled. The study was designed as a randomized phase III study evaluating TTP by log-rank model. There was a clause for premature closure of the trial if fewer than five responses were observed among the first 25 assessable patients in the docetaxel treatment arm.

RESULTS

Eighty-six patients were entered onto the study; 85 were assessable for toxicity and 83 for response. The rate of severe granulocytopenia was not significantly different between the two arms. Nausea (P =.001), vomiting (P <.001), and stomatitis (P =.005) were more common with doxorubicin therapy, whereas neurotoxicity was more frequent with docetaxel treatment. The response rate to doxorubicin therapy was 30% (95% confidence interval, 17% to 46%), whereas no responses to docetaxel therapy were seen (P <.001). In view of this, the trial was closed prematurely and the phase III study part was not conducted.

CONCLUSION

Docetaxel is inactive in soft tissue sarcomas and cannot be recommended for further use in treatment of this disease.

Gemcitabine in advanced adult soft-tissue sarcomas. A phase II study of the EORTC Soft Tissue and Bone Sarcoma Group

Gemcitabine (2'-deoxy-2'-difluorocytidine monohydrochloride) at a dose of 1250 mg/m(2) was given as a 30-min intravenous (i.v.) infusion on days 1 and 8 in a 3-weekly schedule to 32 patients with advanced soft-tissue sarcoma (STS) failing first-line chemotherapy. One patient was ineligible due to a delay between the previous chemotherapy and the start of treatment. Of the eligible patients, median age was 53 years (range 23-73 years). The predominant histological subtype was leiomyosarcoma in 12 patients (38%). The median number of cycles was three (range 1-8 cycles) with a median total dose of gemcitabine of 6.25 g/m(2) (range 1.25-19.97 g/m(2)). The relative dose intensity of gemcitabine was 96% (range 50-103%). Treatment was tolerated very well with non-complicated haematological toxicity as the most frequently observed side-effect. Only one partial tumour response was documented, giving a response rate of 3.23% (95% Confidence Interval (CI): 0.08-16.2%). The median overall survival was 268 days (95% CI: 129-377) and the median time to progression was 45 days (95% CI: 41-79). These results indicate that gemcitabine given at this dose and schedule is not active as second-line therapy in advanced STS.

A human capecitabine excretion balance and pharmacokinetic study after administration of a single oral dose of 14C-labelled drug

An excretion balance and pharmacokinetic study was conducted in cancer patients with solid tumors who received a single oral dose of capecitabine of 2000 mg including 50 microCi of 14C-radiolabelled capecitabine. Blood, urine and fecal samples were collected until radioactive counts had fallen to below 50 dpm/mL in urine, and levels of intact drug and its metabolites were measured in plasma and urine by LC/MS-MS (mass spectrometry) and 19F-NMR (nuclear magnetic resonance) respectively. Based on the results of the 6 eligible patients enrolled, the dose was almost completely recovered in the urine (mean 95.5%, range 86-104% based on radioactivity measurements) over a period of 7 days after drug administration. Of this, 84% (range 71-95) was recovered in the first 12 hours. Over this time period, 2.64% (0.69-7.0) was collected in the feces. Over a collection period of 24-48 h, a total of 84.2% (range 80-95) was recovered in the urine as the sum of the parent drug and measured metabolites (5'-DFCR, 5'-DFUR, 5-FU, FUH2, FUPA, FBAL). Based on the radioactivity measurements of drug-related material, absorption is rapid (tmax 0.25-1.5 hours) followed by a rapid biphasic decline. The parent drug is rapidly converted to 5-FU, which is present in low levels due to the rapid metabolism to FBAL, which has the longest half-life. There is a good correlation between the levels of radioactivity in the plasma and the levels of intact drug and the metabolites, suggesting that these represent the most abundant metabolites of capecitabine. The absorption of capecitabine is rapid and almost complete. The excretion of the intact drug and its metabolites is rapid and almost exclusively in the urine.

Phase I and pharmacokinetic study of an oral platinum complex given daily for 5 days in patients with cancer

PURPOSE

We aimed to determine the maximum-tolerated dose (MTD) clinical toxicities, pharmacokinetics, and pharmacodynamics of oral JM216 given once daily for 5 days to cancer patients.

PATIENTS AND METHODS

Patients who fulfilled standard phase I trial criteria were enrolled. Oral JM216 was given at doses based on patient body-surface area, on an empty stomach, once daily for 5 consecutive days, as 10-, 50-, and 200-mg hard gelatin capsules and with oral antiemetics. The pharmacokinetics of platinum were studied on days 1 and 5 of the first treatment course using atomic absorption spectrophotometry (AAS).

RESULTS

Thirty-two patients received 94 courses of oral JM216 at doses that ranged from 30 to 140 mg/m2 body-surface area for 5 consecutive days. The MTD was 140 mg/m2/d. The dose-limiting toxicities were thrombocytopenia and neutropenia. Hematotoxicity was reversible (nadir, 17 to 21 days; recovery, 28 days), noncumulative, and dependent on the dose and history of previous therapy. There were two instances of neutropenic sepsis. Two-thirds of patients experienced mild nausea, vomiting, or diarrhea. There was no ototoxicity, neurotoxicity, nephrotoxicity, or objective tumor responses. There was a significant correlation between JM216 dose and the day 1 and 5 plasma ultrafiltrate area under the concentration-time curve (AUC; r = .78), which indicates linear pharmacokinetics. There was considerable intersubject pharmacokinetic and pharmacodynamic variability, but a significant sigmoidal relationship between the plasma ultrafiltrate AUC and severity of thrombocytopenia (R2 = .83).

CONCLUSION

We recommend JM216 doses of 100 and 120 mg/m2/d x 5 for previously treated and untreated patients, respectively, for phase II trials.

Ewing's sarcoma and primitive neuroectodermal tumor in adults: are they different from Ewing's sarcoma and primitive neuroectodermal tumor in children?

PURPOSE

To determine whether age at diagnosis influences the behavior of Ewing's sarcoma and primitive neuroectodermal tumor (PNET).

PATIENTS AND METHODS

We reviewed the clinical features, treatment, and outcome of 59 consecutive patients with Ewing's sarcoma and PNET treated on the Adult Sarcoma Unit at our institution from 1980 to 1995.

RESULTS

The 37 male and 22 female patients had a median age of 24 years. Lower limb was the most common primary tumor site. Fifteen patients had nonmetastatic tumor less than 100-mL volume, 27 had nonmetastatic disease greater than 100-mL volume, and 17 had evidence of metastatic disease at presentation. The origin of the primary tumor was soft tissue in 28 cases, bone in 30, and uncertain in one. The Kaplan-Meier estimate of 5-year overall survival (OS) in all patients was 38% and of progression-free survival (PFS), 27%. When patients with metastatic disease at presentation were excluded, these figures increased to 52% and 34%, respectively. Bulk of disease at presentation and response to primary treatment were statistically highly significant predictors of both PFS and OS. Age and tissue of origin of the tumor did not influence outcome.

CONCLUSION

The behavior of Ewing's sarcoma and PNET in adults is no different from its behavior in children. We feel the way forward in the treatment of adults with Ewing's sarcoma and PNET is for them to be included in the current multicenter trials of multidisciplinary treatment directed at children.

Radiofrequency ablation is a feasible therapeutic option in the multi modality management of sarcoma

The role of radiofrequency ablation (RFA) in metastatic sarcoma is not well defined. The aim of this study was to evaluate the efficacy and safety of RFA in a series of sarcoma patients. A retrospective search of a prospectively maintained database identified 13 gastrointestinal stromal tumour (GIST) patients and 12 with other histological subtypes treated with RFA. All the GIST patients received RFA for metastatic disease in the liver: 12 of these responded to the first RFA procedure and one achieved stable disease. Two GIST patients received RFA on two occasions to separate lesions within the liver and both responded to the second RFA procedure. Of the other subtypes: 7 underwent RFA to liver lesions, 5 of these responded to RFA, one progressed and 1 was not assessable for response at the time of analysis. All 5 patients with lung metastases achieved a response following their first RFA procedure. RFA was effective and well tolerated in this series of sarcoma patients. RFA may have a role in patients with GIST who have progression in a single metastasis but stable disease elsewhere. Further larger studies are required to better define the role of this technique in this patient population.

Surgical treatment of lung metastases: The European Organization for Research and Treatment of Cancer-Soft Tissue and Bone Sarcoma Group study of 255 patients

BACKGROUND

Several reports have shown a prolonged survival after surgical treatment of pulmonary metastases from soft tissue sarcomas. However, it is still unclear which prognostic factors predict a favorable outcome. Series are not comparable and the data are conflicting. Therefore, a multi-institutional study was undertaken to analyze prognostic factors in selecting patients for resection of pulmonary metastases from soft tissue sarcomas.

METHODS

This report is a retrospective study of the European Organization for Research and Treatment of Cancer-Soft Tissue and Bone Sarcoma Group. Two hundred fifty-five patients underwent complete resection of lung metastases from soft tissue sarcomas. Cases with chondrosarcoma and small round cell sarcomas like Ewing sarcoma were excluded.

RESULTS

The 3 year and 5 year overall postmetastasectomy survival rates were 54% and 38%, respectively. The disease free postmetastasectomy survival rates were 42% and 35%, respectively. Analysis of prognostic factors for a more favorable outcome revealed disease free intervals of 2.5 years or more, following a resection with microscopically free margins, age less than 40 years, and Grade I and II tumors. These prognostic factors have an independent influence on overall survival, using a multivariate Cox regression model.

CONCLUSIONS

Surgical excision of lung metastases from soft tissue sarcomas is well accepted and should be considered as a first line of treatment if preoperative evaluation indicates that complete clearance of the metastases is possible. Further investigation is needed before chemotherapy can be recommended as additional therapy.

Dichloroacetate induces autophagy in colorectal cancer cells and tumours

BACKGROUND

Dichloroacetate (DCA) has been found to have antitumour properties.

METHODS

We investigated the cellular and metabolic responses to DCA treatment and recovery in human colorectal (HT29, HCT116 WT and HCT116 Bax-ko), prostate carcinoma cells (PC3) and HT29 xenografts by flow cytometry, western blotting, electron microscopy, (1)H and hyperpolarised (13)C-magnetic resonance spectroscopy.

RESULTS

Increased expression of the autophagy markers LC3B II was observed following DCA treatment both in vitro and in vivo. We observed increased production of reactive oxygen species (ROS) and mTOR inhibition (decreased pS6 ribosomal protein and p4E-BP1 expression) as well as increased expression of MCT1 following DCA treatment. Steady-state lactate excretion and the apparent hyperpolarised [1-(13)C] pyruvate-to-lactate exchange rate (k(PL)) were decreased in DCA-treated cells, along with increased NAD(+)/NADH ratios and NAD(+). Steady-state lactate excretion and k(PL) returned to, or exceeded, control levels in cells recovered from DCA treatment, accompanied by increased NAD(+) and NADH. Reduced k(PL) with DCA treatment was found in HT29 tumour xenografts in vivo.

CONCLUSIONS

DCA induces autophagy in cancer cells accompanied by ROS production and mTOR inhibition, reduced lactate excretion, reduced k(PL) and increased NAD(+)/NADH ratio. The observed cellular and metabolic changes recover on cessation of treatment.

Phase I trial of ZD1694, a new folate-based thymidylate synthase inhibitor, in patients with solid tumors

PURPOSE

To perform a phase I clinical and pharmacologic study of ZD1694 (Tomudex, Alderley Park, United Kingdom), a new folate-based thymidylate synthase (TS) inhibitor, in patients with advanced malignancy.

PATIENTS AND METHODS

From February 1991 to January 1993, 61 patients with a range of solid tumor received 161 courses of ZD1694 given as a single 15-minute intravenous infusion every 3 weeks, at escalating doses from 0.1 to 3.5 mg/m2. Pharmacokinetic (PK) analysis was performed with the first two courses of treatment. There were 33 men and 28 women with a median age of 53 years (range, 21 to 73). Fifty-five patients (90%) had previously received chemotherapy.

RESULTS

Reversible liver toxicity and dose-related gastrointestinal (GI) and bone marrow toxicity occurred at > or = 1.6 mg/m2. Liver function usually returned to normal with repeated treatment, but GI and bone marrow toxicities generally became more severe. No renal toxicity was observed. The maximum-tolerated dose (MTD) was 3.5 mg/m2, at which, in addition to antiproliferative toxicities, four of six patients (67%) developed severe malaise that consisted of anorexia, nausea, and asthenia, with rapidly decreasing performance status that limited re-treatment. Abnormal liver function was also seen in four patients (67%). At 3.0 mg/m2, grades III and IV diarrhea were seen in six of 23 patients (26%) and grade IV myelosuppression in two others. Liver toxicity was self-limiting and not associated with severe malaise. Two patients had a partial response to treatment. PK analysis showed that plasma elimination was triexponential, with pronounced variability in the mean terminal half-life (t1/2gamma) for a given dose ranging from 8.2 to 105 hours. There was a linear relationship between dose and both the area under the concentration-time curve (AUC) and maximum concentration (Cmax), but no clear association between these parameters and response or toxicity.

CONCLUSION

The dose of ZD1694 recommended for phase II trials is 3.0 mg/m2.

Influence of pH on the uptake of 5-fluorouracil into isolated tumour cells

To investigate the possible dependence of 5-fluorouracil (5FU) uptake in tumours on the intra- (pHi) and extracellular (pHe) pH, a pH gradient (deltapH) was imposed across the plasma membrane of ascites tumour cells in vitro, similar to that known to occur in some solid tumours in vivo, by incubation in media of PHe 5-8. A > or = 2:1 (intracellular/extracellular) accumulation of radiolabelled 5FU occurred after 5 min incubation of the cells with 0.5 mM 5FU at pHe of 5.0, 5.5 or 6.0. 5FU metabolism is slow under these conditions, and 5FU uptake was not affected by longer incubations up to 20 min, nor by the absence of a sodium gradient. pHi was estimated from the distribution of the weak acid, 5.5-dimethyl-2,4-oxazolidione ([14C]DMO) across the cell membrane. There was significant correlation between the intracellular/extracellular 5FU ratio and pHe (from pHe 6-8), deltapH and pHi (P < 0.02). Similar results were obtained with HT29 cells. Incubation with a drug that made plasma membranes permeable to H+ significantly decreased 5FU uptake in Lettre cells. The co-transport of 5FU may occur on a proton symport using the proton motive force of the deltapH.

Efficacy and safety of sorafenib in a subset of patients with advanced soft tissue sarcoma from a Phase II randomized discontinuation trial

AIM

Phase II multi-disease randomized discontinuation trial to assess the safety and efficacy of sorafenib including patients with advanced soft tissue sarcoma (STS).

METHODS

Sorafenib (400 mg twice daily) was initially administered for 12 weeks. Patients with: ≥25% tumour shrinkage continued sorafenib; ≥25% tumour growth discontinued; other patients were randomized and received sorafenib or placebo.

RESULTS

Twenty-six patients (median age 55 years) were enrolled. Common drug-related adverse events, including fatigue, hand-foot skin reaction, rash or gastrointestinal disturbances, were manageable, reversible and generally low grade. Fatigue, skin toxicity, nausea, diarrhoea and hypertension occurred at grade ≥3 in 19% of patients. After 12 weeks eight (31%) patients had not progressed. Three patients who experienced tumour shrinkage and continued on sorafenib, and five (19%) were randomized either to continue sorafenib or to receive placebo. Of the three patients randomized to sorafenib, one achieved a partial response and two had SD. Overall one patient achieved a partial response and three further patients achieved minor responses.

CONCLUSIONS

There was evidence of disease activity in STS as defined by tumor regressions including one objective partial response. Further investigation in STS is warranted.

The use of paediatric chemotherapy protocols at full dose is both a rational and feasible treatment strategy in adults with Ewing's family tumours

BACKGROUND

Ewing's sarcoma and primitive neuroectodermal tumour (ES/PNET) are rare, limiting opportunities for therapy studies in adults. Chemotherapy regimens adapted from paediatric studies are often used for adults but concerns about poor outcome and treatment toxicity may adversely affect drug dose intensity. We present our experience using a paediatric protocol at full dose.

PATIENTS AND METHODS

Records of 34 patients with ES/PNET who received the IVAD chemotherapy regimens were reviewed. Received drug dose intensity, toxicity and survival data were collected.

RESULTS

Received dose intensity in 30 evaluable patients was 0.92 compared to the standard IVAD schedule. Myelosuppression was the major toxicity, 83% of patients experienced grade 4 neutropenia. There was no major renal or cardiac toxicity. In patients without metastases at presentation, five-year overall survival was 63% and progression free survival was 39%. Tumour burden at presentation was statistically significantly associated with survival (P = 0.002). The five-year survival rate of 80% in patients presenting with low volume non metastatic disease was equivalent to published paediatric series.

CONCLUSIONS

Although the IVAD chemotherapy regimens are myelotoxic in adults, they can be given safely. We recommend that adults with ES/PNET should be included in current multicentre, multidisciplinary treatment studies directed at children.

The measurement of polyglutamate metabolites of the thymidylate synthase inhibitor, ICI D1694, in mouse and human cultured cells

A method is described for the measurement of the polyglutamates of the quinazoline thymidylate synthase inhibitor, N-(5-[N-(3,4-dihydro-2-methyl-4-oxoquinazolin- 6-ylmethyl)-N-methylamino]-2-theonyl)-L-glutamic acid (ICI D1694). This involved incubation of cells with [5-3H]ICI D1694, extraction of the polyglutamates and their analysis by HPLC using an ion-pairing method. Co-chromatography with ICI D1694 and its synthetic di-hexaglutamate standards (UV detection) aided identification of the [3H]polyglutamates in the fractions recovered from the HPLC. Recovery of the polyglutamates at each stage of extraction and analysis was very good (77-84% overall recovery). Polyglutamates readily accumulated as the tri-, tetra and penta forms and occasionally a small amount of hexaglutamate was found. After mouse L1210 leukemia or human W1L2 lymphoblastoid cells were incubated for 30 min with 0.1 microM [3H]ICI D1694 there was a approximately 6-fold concentration effect intracellularly with most of the 3H associated with polyglutamate forms (approximately 75% and 96% for the L1210 and W1L2, respectively). Even some of the higher chain length tetra- and pentaglutamates could be detected at this time. After 4 hr incubation the total level of intracellular 3H had risen to 2-3 microM, greater than 96% of which was associated with polyglutamates (mainly tetra- and pentaglutamates). Four other human cell lines, two ovarian (CH1 and 41M), the MCF-7 breast and the HT-29 colon, were examined for their ability to form intracellular polyglutamates. A 4 hr incubation with 0.1 microM [3H]ICI D1694 resulted in a substantial intracellular accumulation of the drug (20-100-fold) in its polyglutamate forms with only 2-20% remaining as the parent monoglutamate, depending on the cell line. The major polyglutamate was again cell line dependent, ranging from the tri to the penta form. Prolonging the incubation time to 24 hr allowed a further accumulation of drug with a larger percentage appearing as tri- to hexaglutamates. Although cell lines differed in the total level of polyglutamates formed and the pattern of chain length observed, rapid and extensive polyglutamation of ICI D1694 occurred in all the cell types examined.

A pharmacokinetic and pharmacodynamic study in vivo of human HT29 tumours using 19F and 31P magnetic resonance spectroscopy

19F-MRS (magnetic resonance spectroscopy) was used to study the pharmacokinetics of 5-fluorouracil (5-FU) in human (HT29) tumour xenografts, with and without pretreatment of the mice using either thymidine (40 min) or interferon-alpha (2 and 24 h). A 200 mg/kg i.p. bolus dose of 5-FU was eliminated from control tumours with a t1/2 of 25.4 +/- 2 min (mean +/- SEM, n = 11), while both thymidine (500 mg/kg) and interferon (50,000 IU/mouse) significantly increased t1/2 to 36.5 +/- 6.1 (n = 5) and 48.1 +/- 13.6 min (n = 4), respectively (P = 0.04, Gabriel's ANOVA). Thymidine increased 5-FU anabolism to cytotoxic 5-fluoronucleotides, and decreased the amount of tumour catabolites; the latter probably recirculated from liver since isolated HT29 cells did not catabolize 5-FU. These in vivo observations were confirmed by 19F-MRS quantification of tumour extracts. Interferon did not significantly affect 5-FU metabolism in the tumour or liver, nor the 5-FU t1/2 in liver. Treatment of tumours with 5-FU or interferon had no effect on tumour growth, whereas the combination strongly inhibited growth. 31P-MRS of HT29 tumours showed that 2 and 24 h after i.p. injections of interferon there was a significant increase in the pHint of 0.3 +/- 0.04 units (P = 0.002), while pHext and the tumour NTP/Pi ratio were unchanged. The large increase in the negative pH gradient (-delta pH) across the tumour plasma membrane caused by interferon suggest the delta pH may be a factor in tumour retention of 5-FU, as recently shown in isolated tumour cells.

Pharmacokinetics of the 13C labeled anticancer agent temozolomide detected in vivo by selective cross-polarization transfer

The anticancer agent temozolomide labeled with 13C (8-Carbamoyl-3-13C-methylimidazo-[5,1-d]-1,2,3,5-tetrazin-4-(3H)-o ne), was noninvasively detected in subcutaneous RIF-1 tumors by a selective cross polarization 13C NMR method, at a field strength of 9.4T. Pharmacokinetics of the drug, at a dose of 150 mg/kg, were determined for intravenous and intraperitoneal models of administration (three animals per mode). The half-life of the drug in the tumors was approximately 60 min. The uptake and clearance of the drug, however, varied significantly between individual hosts, for both modes of administration. These results demonstrate the feasibility of obtaining pharmacokinetics of anticancer agents for individual tumors without the need for a label that might modify drug activity (e.g., fluorine). The variability of the in vivo measurements, even within the same tumor model, demonstrates the necessity of directly monitoring the tumor to evaluate drug pharmacokinetics.

Incidence of P-glycoprotein overexpression and multidrug resistance (MDR) reversal in adult soft tissue sarcoma

Multidrug resistance (MDR) is a widespread problem in the treatment of neoplastic diseases and may limit the effectiveness of treatment of adult soft tissue sarcomas (STS). We examined the levels of expression of the MDR marker P-glycoprotein (Pgp) in fresh, surgical material and matched paraffin-embedded tissue using MRK-16 and JSB-1 monoclonal antibodies. Using fresh tumour material in short-term culture an assessment of doxorubicin sensitivity (MTT assay) and MDR modulation using PSC-833 in daunorubicin (DNR) accumulation experiments (FACS analysis) was carried out. 44 patients were studied at various disease stages with a mean follow-up duration of 487 days (range: 45-1095 days). Immunocytochemistry and immunohistochemistry showed 62% and 58%, respectively, of STS samples were positive for Pgp. Patients showing negative Pgp expression had a median survival of 544 days versus 431 days for Pgp-positive patients (P=0.311), with disease-free survival medians of 508 and 355 days, respectively (P=0.203). In vitro doxorubicin sensitivity was not informative in this respect and there was no apparent relationship between this and Pgp expression. Eleven out of 29 samples evaluated for MDR modulation showed enhanced tumour cell DNR accumulation. However, the effects of PSC-833 on drug accumulation in clinical material were modest compared with those seen for MDR cell lines, with a maximum of only 20% enhancement. Moreover, there was no relationship between the extent of PSC-833 effects on accumulation and the levels of Pgp seen in the STS samples. Nevertheless, we show evidence that a proportion of cases of STS express moderate to high levels of Pgp. There may be a role for MDR modulating agents in association with doxorubicin in the treatment of these tumours, either in the adjuvant setting or at first relapse.

A randomised trial comparing combination chemotherapy using mitomycin C, mitozantrone and methotrexate (3M) with vincristine, anthracycline and cyclophosphamide (VAC) in advanced breast cancer

This paper describes a randomised clinical trial in patients with advanced breast cancer, comparing the regimen 3M, mitomycin C 7-8 mg m-2 (day 1), mitozantrone 7-8 mg m-2 (day 1 and 21), methotrexate 35 mg m-2 (day 1 and 21) given on a 42 day cycle with a standard anthracycline containing regimen, VAC, vincristine 1.4 mg m-2 (day 1), anthracycline (adriamycin or epirubicin) 30 mg m-2 (day 1), cyclophosphamide 400 mg m-2 (day 1) given on a 21 day cycle. Of a total of 217 patients, 107 were randomised to 3M and 110 to VAC and a mean of 5.5 courses was given per patient. The overall response rate (complete and partial) was 53% (95% Confidence Limits (CL): 43-62%) for 3M and 49% (CL; 39-58%) for VAC. The response according to sites of metastases was the same for both treatment groups. Symptomatic toxicity including alopecia, neuropathy, vomiting (P less than 0.001) and nausea (P less than 0.01) were significantly less for 3M. Myelosuppression including leucopenia (P less than 0.001) and thrombocytopenia (P less than 0.001) was significantly greater with 3M at day 21, although there was no difference in nadir counts in patients at special risk of myelosuppression and there was no evidence of an increase in infective or bleeding complications. There was no significant difference in the duration of response to 3M (10 months, CL 6-15) and VAC (11 months, CL 7-12), nor in survival (3M, 8 months, CL 6-12; VAC, 10 months, CL 8-12). These results indicate that 3M is as effective as, but has significantly less symptomatic toxicity than, an anthracycline containing regimen for the treatment of advanced breast cancer.

In vitro and in vivo antitumor activity of benzyl isothiocyanate: a natural product from Tropaeolum majus

Cultured cells of Tropaeolum majus produce significant amounts of benzyl glucosinolate which, through enzymatic hydrolysis, results in the production of benzyl isothiocyanate (BITC). This study reports on the in vitro anticancer properties of BITC against a variety of human and murine tumor cell lines by four independent methods; SRB, MTT, cell counting, and clonogenic assays. Regardless of the assay used, BITC showed promising cytotoxicity in the low micromolar range (0.86 to 9.4 microM) against four human ovarian carcinoma cell lines (SKOV-3, 41-M, CHl, CHlcisR), a human lung tumor (H-69), a murine leukemia (L-1210), and a murine plasmacytoma (PC6/sens). The L1210 cells were most sensitive. BITC administered to mice bearing the ADJ/PC6 plasmacytoma subcutaneous tumor showed toxic effects at a dose of 200 mg/kg (within 24 h of drug administration) but no reduction in tumor mass. However, the growth inhibitory properties of BITC against a range of tumor cell types warrant further in vivo anti-tumor evaluation as well as its biotechnological production.