Accelerated BEP for metastatic germ cell tumours: a multicenter phase II trial by the Australian and New Zealand Urogenital and Prostate Cancer Trials Group (ANZUP).

BACKGROUND: This Australian single-arm, multicenter, phase II trial evaluated feasibility, tolerability and activity of accelerated bleomycin, etoposide and cisplatin (BEP) as first-line chemotherapy for metastatic germ cell tumours. PATIENTS AND METHODS: Patients were planned to receive cisplatin 20 mg/m(2) and etoposide 100 mg/m(2) days 1-5, and pegfilgrastim 6 mg day 6, all repeated every 2 weeks for four cycles (three cycles for good prognosis). Bleomycin was given at 30 000 IU weekly to a total of 12 doses (9 doses for good prognosis). Primary end point was feasibility, defined as the proportion of patients able to complete the etoposide and cisplatin components of BEP and be eligible to receive a fourth cycle of BEP by day 50. RESULTS: Twelve poor, 16 intermediate and 15 good prognosis (n = 43) eligible patients were enrolled. Two patients aged >40 years were ineligible and excluded from analyses. The regimen was feasible in 86%, not feasible in 7% and not assessable in 7% of patients. Most common grade 3/4 adverse events were non-neutropenic infection (16%) and febrile neutropenia (12%). Complete response (CR) to chemotherapy and surgery was achieved in 33% poor-prognosis, 81% intermediate-prognosis and 100% good-prognosis patients. At median follow-up of 27 months (range 6-42), the 2-year progression-free survival was 50% for poor-prognosis, 94% for intermediate-prognosis and 92% for good-prognosis patients. CONCLUSION: Accelerated BEP is feasible and tolerable. Efficacy data appear to be promising. This trial and a similar UK study provide the rationale for a randomised trial comparing accelerated versus standard BEP. Australian New Zealand Clinical Trials Registry Registration number. ACTRN 12607000294459.

Phase I trial of CYT997, a novel cytotoxic and vascular-disrupting agent.

BACKGROUND: CYT997 is a novel microtubule inhibitor and vascular-disrupting agent with marked preclinical anti-tumour activity. METHODS: This phase I dose-escalation study assessed the safety, tolerability, pharmacokinetics and pharmacodynamics of CYT997 administered by continuous intravenous infusion over 24 h every 3 weeks to patients with advanced solid tumours. RESULTS: Thirty-one patients received CYT997 over 12 dose levels (7-358 mg m(-2)). Doses up to 202 mg m(-2) were well tolerated. Dose-limiting toxicities were observed at 269 and 358 mg m(-2), consisting of grade 3 prolonged corrected QT interval in two patients and grade 3 hypoxia and grade 4 dyspnea in one patient. All toxicities were reversible. The pharmacokinetics of CYT997 were linear over the entire dose range. Dynamic contrast-enhanced magnetic resonance imaging scans showed significant changes in tumour K(trans) values consistent with vascular disruption in 7 out of 11 evaluable patients treated at CYT997 doses of >or=65 mg m(-2). Moreover, plasma levels of von Willebrand factor and caspase-cleaved cytokeratin-18 increased post-treatment at higher dose levels. Among 22 patients evaluable for response, 18 achieved stable disease for >2 cycles. CONCLUSIONS: CYT997 was well tolerated at doses that were associated with pharmacodynamic evidence of vascular disruption in tumours.

A phase Ib trial of docetaxel, carboplatin and erlotinib in ovarian, fallopian tube and primary peritoneal cancers.

The safety and maximum tolerated dose (MTD) of erlotinib with docetaxel/carboplatin were assessed in patients with ovarian cancer. Chemonaive patients received intravenous docetaxel (75 mg m(-2)) and carboplatin (area under the curve 5) on day 1 of a 3-week cycle, and oral erlotinib at 50 (cohort 1), 100 (cohort 2a) or 75 mg day(-1) (cohort 2b) for up to six cycles. Dose-limiting toxicities were determined in cycle 1. Forty-five patients (median age 59 years) received treatment. Dose-limiting toxicities occurred in 1/5/5 patients (cohorts 1/2a/2b). The MTD of erlotinib in this regimen was determined to be 75 mg day(-1) (cohort 2b; the erlotinib dose was escalated to 100 mg day(-1) in 11 out of 19 patients from cycle 2 onwards). Neutropaenia was the predominant grade 3/4 haematological toxicity (85/100/95% respectively). Common non-haematological toxicities were diarrhoea, fatigue, nausea and rash. There were five complete and seven partial responses in 23 evaluable patients (52% response rate). Docetaxel/carboplatin had no measurable effect on erlotinib pharmacokinetics. In subsequent single-agent maintenance, erlotinib was given at 100-150 mg day(-1), with manageable toxicity, until tumour progression. Further investigation of erlotinib in epithelial ovarian carcinoma may be warranted, particularly as maintenance therapy.

Does body mass index affect progression-free or overall survival in patients with ovarian cancer? Results from SCOTROC I trial.

BACKGROUND: Previous studies have indicated an association between obesity and poor survival in several tumour types, including ovarian cancer. We sought to test the hypothesis that obesity reduces survival in a large, well-characterised and relatively homogeneous cohort of ovarian cancer patients. PATIENTS AND METHODS: The relationship between body mass index (BMI) and overall survival (OS) and progression-free survival (PFS) in 1067 patients participating in the Scottish Randomised Trial in Ovarian Cancer I trial was assessed. All patients received first-line carboplatin/taxane chemotherapy. The dose of carboplatin was determined by a measured glomerular filtration rate (GFR), ensuring accurate dosing in all categories of BMI and the dose of taxane was not capped. Patients were assigned to one of four categories: underweight (BMI < 18.5), ideal weight (BMI 18.5-24.9), overweight (BMI 25-29.9) or obese (BMI >or= 30). RESULTS: There were neither statistically significant differences in PFS or OS between these four groups nor were there any differences in taxane or carboplatin dose intensity. Furthermore, there was no association between BMI and tumour stage or grade at presentation, or completeness of debulking surgery. CONCLUSIONS: Obese patients with epithelial ovarian cancer do not have a poorer prognosis, provided that they receive optimal doses of chemotherapy based on measured GFR and actual body weight.

Cell cycle arrests and radiosensitivity of human tumor cell lines: dependence on wild-type p53 for radiosensitivity.

Loss of p53 function has been shown to cause increased resistance to ionizing radiation in normal murine cells; however, the role of p53 in radioresistance of human tumor cells is less clear. Since wild-type p53 function is required for radiation-induced G1 arrest, we measured G1 arrest in 12 human tumor cell lines that have a wide range of radiosensitivities (surviving fraction at 2 Gy, 0.11-0.8). We observed a significant correlation between the level of ionizing radiation-induced G1 arrest and radiosensitivity. Cell lines having G1 arrest are more radiosensitive. There is no correlation between maximal G2 arrest and radiosensitivity. Expression of a dominant-negative mutant of p53 (codon 143, Val to Ala) in transfectants of the radiosensitive human ovarian cell line A2780 abrogates the radiation-induced G1 arrest. Such mutant p53 transfectants are more resistant to ionizing radiation than the parental line and vector-alone transfectants, as measured by clonogenic assays. These results support the concept that wild-type p53 function is required for sensitivity of tumor cells to DNA-damaging agents, such as ionizing radiation, and that the loss of p53 function in certain human tumor cells can lead to resistance to ionizing radiation.

Phase I clinical and pharmacokinetic study of 3'-deamino-3'-(2-methoxy-4-morpholinyl)doxorubicin (FCE 23762).

Methoxymorpholinyldoxorubicin (FCE 23762) is a novel, highly lipophilic doxorubicin analogue. It possesses potent in vitro and in vivo antitumor activity including efficacy in multidrug-resistant tumor cell lines. It is also metabolically activated in vivo resulting in an 80-fold increase in potency over the parent drug. In this phase I study the drug was administered by i.v. bolus injection at 3-week intervals. Fifty-three patients with refractory solid tumors were treated; 133 courses of FCE 23762 were administered at doses ranging from 30 to 2250 micrograms/m2. The dose limiting toxicity was reversible myelo-suppression (granulocytopenia and thrombocytopenia), demonstrating a delayed nadir and recovery in comparison to doxorubicin. Other toxicities included transient elevation of hepatic transaminases, delayed and prolonged nausea and vomiting, mucositis, anorexia, fatigue, and diarrhea. Heavily pretreated patients demonstrated more myelosuppression than previously untreated patients at 1250 micrograms/m2. No cardiotoxicity was observed. Four objective tumor responses were seen: one complete response in a patient with pelvic recurrence of cervical cancer; one partial response in a patient with cutaneous and lymph gland metastases from head and neck cancer; and two minor responses in patients with liver metastases from colorectal cancer. Plasma concentrations of FCE 23762 and its 13-dihydro metabolite, FCE 26176, were measured in 20 patients at doses > or = 675 micrograms/m2, using HPLC with fluorescence detection. The area under the plasma concentration-time curve ranged from 30 to 80 ng/h/ml; plasma data suggested linear kinetics in the range of tested doses (although there was considerable interpatient variability). The maximum tolerated dose defined in this study using this schedule is 1500 micrograms/m2. A safe phase II dose for previously untreated patients using this schedule is 1250 micrograms/m2; however, this may actually be below the optimal dose for this patient population.

Docetaxel and cisplatin in combination as first-line chemotherapy for advanced epithelial ovarian cancer. Scottish Gynaecological Cancer Trials Group.

PURPOSE: A prospective, nonrandomized, multicenter, open feasibility study of cisplatin and docetaxel as first-line chemotherapy in International Federation of Gynecology and Obstetrics (FIGO) stage IC-IV epithelial ovarian cancer was conducted. The primary end point was the incidence of severe fluid retention that necessitated treatment withdrawal. PATIENTS AND METHODS: Cisplatin and docetaxel were administered every 3 weeks for six planned cycles, with a 5-day prophylactic dexamethasone regimen (8 mg two times per day). One hundred patients (median age, 53 years; range, 24 to 71 years) received a total of 512 cycles of chemotherapy in two cohorts: cohort 1, 49 patients, 258 cycles (cisplatin 75 mg/m(2) and docetaxel 75 mg/m(2)); cohort 2, 51 patients, 254 cycles (cisplatin 75 mg/m(2) and docetaxel 85 mg/m(2)). RESULTS: No patients were taken off study because of fluid retention. Sixty-six patients completed six cycles of protocol therapy; 16 stopped early because of toxicity (neurotoxicity in six patients, nephrotoxicity in three, neutropenia in two, and hypersensitivity, diarrhea and vomiting, skin rash, clinical deterioration, and patient's wishes in one patient each). Grade 3/4 neutropenia was observed in more than 75% of patients and seemed to be cumulative. Patients in cohort 2 had significantly more severe neutropenia and lethargy than those in cohort 1. In addition, there were five treatment-related deaths in cohort 2 (three neutropenia and two upper gastrointestinal hemorrhage). Neurotoxicity (mainly sensory, > grade 1) was observed in 23 patients. The overall clinical response rate was 69% (complete response, 38%; partial response, 31%); CA-125 response rate was 73%. Median progression-free survival for the group was 12 months. CONCLUSION: Cisplatin and docetaxel can be administered at doses of 75 mg/m(2) and 75 mg/m(2), respectively, every 3 weeks, and the utility of this regimen is not limited by fluid retention. However, 33 of 100 patients were unable to complete the planned six cycles, which may explain, in part, the poor overall progression-free survival. Increasing the docetaxel dose to 85 mg/m(2) adds unacceptable hematologic toxicity and potential risks to the patient.

Phase I trial of intraperitoneal injection of the E1B-55-kd-gene-deleted adenovirus ONYX-015 (dl1520) given on days 1 through 5 every 3 weeks in patients with recurrent/refractory epithelial ovarian cancer.

PURPOSE: Resistance to chemotherapy in ovarian cancer is frequently associated with mutations in the p53 gene. The adenovirus dl1520 (ONYX-015) with the E1B 55-kd gene deleted, allowing selective replication in and lysis of p53-deficient tumor cells, has shown preclinical efficacy against p53-deficient nude mouse-human ovarian carcinomatosis xenografts. PATIENTS AND METHODS: We undertook a phase I trial of intraperitoneal dl1520 in patients with recurrent ovarian cancer. Sixteen women with recurrent/refractory ovarian cancer received 35 cycles (median, two cycles) of dl1520 delivered on days 1 through 5 in four dose cohorts: 1 x 10(9) plaque forming units (pfu), 1 x 10(10) pfu, 3 x 10(10) pfu, and 1 x 10(11) pfu. RESULTS: The most common significant toxicities related to virus administration were flu-like symptoms, emesis, and abdominal pain. One patient receiving 1 x 10(10) pfu developed common toxicity criteria grade 3 abdominal pain and diarrhea, which was dose-limiting. The maximum-tolerated dose was not reached at 10(11) pfu, and at this dose level patients did not experience significant toxicity. There was no clear-cut evidence of clinical or radiologic response in any patient. Blood samples were taken for adenovirus DNA and neutralizing antibodies. Polymerase chain reaction data indicating presence of virus up to 10 days after the final (day 5) infusion of dl1520 are suggestive of continuing viral replication. CONCLUSION: This article therefore describes the first clinical experience with the intraperitoneal delivery of any replication-competent/-selective virus in cancer patients.

Phase I clinical and pharmacokinetic study of PK1 [N-(2-hydroxypropyl)methacrylamide copolymer doxorubicin]: first member of a new class of chemotherapeutic agents-drug-polymer conjugates. Cancer Research Campaign Phase I/II Committee.

PK1 comprises doxorubicin covalently bound to N-(2-hydroxypropyl)methacrylamide copolymer by a peptidyl linker. Following cellular uptake via pinocytosis, the linker is cleaved by lysosomal enzymes, allowing intratumoral drug release. Radically altered plasma and tumor pharmacokinetics, compared to free doxorubicin, and significant activity in animal tumors have been demonstrated preclinically. We aimed to determine the maximum tolerated dose, toxicity profile, and pharmacokinetics of PK1 as an i.v. infusion every 3 weeks to patients with refractory or resistant cancers. Altogether, 100 cycles were administered (range, 20-320 mg/m2 doxorubicin-equivalent) to 36 patients (20 males and 16 females) with a mean age of 58.3 years (age range, 34-72 years). The maximum tolerated dose was 320 mg/m2, and the dose-limiting toxicities were febrile neutropenia and mucositis. No congestive cardiac failure was seen despite individual cumulative doses up to 1680 mg/m2. Other anthracycline-like toxicities were attenuated. Pharmacokinetically, PK1 has a distribution t(1/2) of 1.8 h and an elimination t(1/2) averaging 93 h. 131I-labeled PK1 imaging suggests PK1 is taken up by some tumors. Responses (two partial and two minor responses) were seen in four patients with NSCLC, colorectal cancer, and anthracycline-resistant breast cancer. PK1 demonstrated antitumor activity in refractory cancers, no polymer-related toxicity, and proof of principle that polymer-drug conjugation decreases doxorubicin dose-limiting toxicities. The recommended Phase II dose is 280 mg/m2 every 3 weeks. Studies are planned in colorectal, NSCLC, and breast cancer patients.

A phase I and pharmacokinetic study of LY231514, the multitargeted antifolate.

LY231514 is a novel antifolate that principally inhibits thymidylate synthase, but with additional folate-dependent enzyme targets. A Phase I study of single-agent LY231514 administered as a daily i.v. infusion over 10 minutes for 5 days, repeated every 3 weeks, was conducted to evaluate the maximum tolerated dose, pharmacokinetic profile, and antitumor activity of the drug using this schedule. Thirty-eight patients with advanced malignancies that were refractory or not amenable to standard therapy were treated with a total of 116 courses of LY231514, escalating treatment doses through 10 dose levels, from 0.2-5.2 mg/m2/day. No objective clinical responses were observed, although minor antitumor activity not fulfilling the response criteria was seen in three patients. A maximum tolerated dose of 4.0 mg/m2/day was determined, with neutropenia as the predominant dose-limiting toxicity. Reversible disturbances of liver biochemistry, fulfilling the protocol definitions of dose-limiting toxicity, were also observed. Other toxicities included diarrhea, mucositis, skin rash, and fatigue. Pharmacokinetic studies were performed at all treatment levels. Analysis showed a linear relation between administered dose and both maximum plasma concentration (Cmax) and area under the plasma concentration/time curve. The drug was cleared with a day 1 total body clearance of 108.9 +/- 38.8 ml/min/m2, with plasma concentrations declining with a mean harmonic terminal half-life of 1.4 +/- 0.98 h. When given by this schedule, LY231514 is tolerable, and Phase II studies are in progress.

New directions in testicular cancer; molecular determinants of oncogenesis and treatment success.

Metastatic testicular cancer is highly curable with conventional cytotoxic drugs. This is in contrast to most other metastatic solid tumours which can only be palliated with chemotherapy achieving only a modest impact on overall survival. If we could understand at the molecular level why chemotherapy is so effective in the treatment of testicular cancer, we may be better able to move other forms of metastatic cancer into the curable bracket. Most cytotoxic drugs appear to induce cell death by activating intracellular apoptotic mechanisms. Thus, the ability of a cancer to activate and execute such mechanisms in response to treatment is paramount in determining the effectiveness of chemotherapy. The basic study of cancer molecular biology is providing some insight into the proteins involved in this process and the ability to apply this information to actual human tumours is essential to rationalise clinical treatment failures at a molecular level. Testicular cancer provides an excellent model system in this analysis. Whereas there are large numbers of patients that are cured by chemotherapy, there are some whose cancers become resistant to treatment. An understanding of testicular cancer molecular biology may allow the identification of the genes regulating such a crucial behavioural switch. It may then be possible to manipulate specific signalling pathways to overcome drug resistance. This review focuses on recent developments in our understanding of the molecular biology of testicular cancer. A number of key players have been implicated including p53, pRb, cyclin D2, p INK proteins, c-kit and the bcl-2 family of proteins. The exact manner by which cellular transformation occurs has still not been established, but it is clear that many of the above proteins also have important roles in normal spermatogenesis. This is a developmental phase when the generation of genetic diversity is at a premium, but when selective apoptotic mechanisms are paramount. We discuss why this may be relevant to the behaviour of germ cell tumours and address possible reasons why they can become resistant to conventional therapy.

A pilot study of continuous infusional 5-fluorouracil, doxorubicin and cyclophosphamide in breast cancer.

The purpose of this study was to evaluate the toxicity and activity of continuous infusional 5-fluorouracil (5-FU) given at three dose levels in combination with cyclophosphamide and doxorubicin (FAC) in women with breast cancer. Thirty-nine patients with either primary tumours >3 cm prior to surgery (n = 24) or metastatic disease (n = 15) received cyclophosphamide 600 mg/m2 and doxorubicin 50 mg/m2 as an intravenous bolus every 3 weeks for six courses. Continuous infusional 5-FU was delivered via a central venous line for a maximum of 18 weeks at dose levels of 100 mg/m2 per day (n = 6), 150 mg/m2 per day (n = 3) and 200 mg/m2 per day (n = 30). At the 200 mg/m2 per day dose level, 36% of patients required dose delays and 23% dose reductions; there was one death due to neutropenic sepsis. Hickman line complications occurred at all dose levels, particularly thrombosis (18%) and infection (33%). The response rate was 62% (95% confidence interval (CI) 32-84) for metastatic disease, including five complete responses (CRs). The response rate for primary tumours prior to surgery was 81% (95% CI 57-95) including six clinical CRs. Infusional FAC is an active regimen and has an acceptable toxicity profile. It does not, however, appear to offer any significant advantage over other chemotherapy regimens. This study does not support the further evaluation of infusional 5-FU at these doses in combination with doxorubicin and cyclophosphamide.

Adjuvant 5-flurouracil, alpha-interferon and interleukin-2 versus observation in patients at high risk of recurrence after nephrectomy for renal cell carcinoma: results of a phase III randomised European Organisation for Research and Treatment of Cancer (Genito-Urinary Cancers Group)/National Cancer Research Institute trial.

BACKGROUND: The purpose of this trial was to compare adjuvant 5-flurouracil, alpha-interferon and interleukin-2 to observation in patients at high risk of recurrence after nephrectomy for renal cell carcinoma (RCC) in terms of disease free survival, overall survival and quality of life (QoL). PATIENTS AND METHODS: Patients 8weeks post nephrectomy for RCC, without macroscopic residual disease, with stage T3b-c,T4 or any pT and pN1 or pN2 or positive microscopic margins or microscopic vascular invasion, and no metastases were randomised to receive adjuvant treatment or observation. QoL was assessed by European Organisation for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire-30 (QLQC-30). Treatment delivery and toxicity were monitored. The trial was designed to detect an increase in 3year disease free survival (DFS) from 50% on observation to 65% on treatment (hazard ratio (HR)=0.63) with 90% power and two-sided alpha=0.05. RESULTS: From 1998 to 2007, 309 patients were randomised (155 to observation; 154 to treatment). 35% did not complete the treatment, primarily due to toxicity (92% of patients experienced ⩾grade 2, 41% ⩾grade 3). Statistically significant differences between the arms in QoL parameters at 2months disappeared by 6months although there was suggestion of a persistent deficit in fatigue and physical function. Median follow-up was 7years (maximum 12.1years). 182 patients relapsed or died. DFS at 3years was 50% with observation and 61% with treatment (HR 0.84, 95% confidence interval (CI) 0.63-1.12, p=0.233). 124 patients died. Overall survival (OS) at 5years was 63% with observation and 70% with treatment (HR 0.87, 95% CI 0.61-1.23, p=0.428). CONCLUSIONS: The treatment is associated with significant toxicity. There is no statistically significant benefit for the regimen in terms of disease free or overall survival.

SCOTROC 2A: carboplatin followed by docetaxel or docetaxel-gemcitabine as first-line chemotherapy for ovarian cancer.

The feasibility of sequential carboplatin followed by docetaxel-based therapy for untreated ovarian cancer was determined. Patients received four q3w cycles of carboplatin AUC 7, then four q3w cycles of either docetaxel 100 mg m(-2) (day 1) (arm A); docetaxel 75 mg m(-2) (day 8) and gemcitabine 1250 mg m(-2) (days 1,8) (arm B) or docetaxel 25 mg m(-2) and gemcitabine 800 mg m(-2) (both given weekly (days 1,8,15)) (arm C). A total of 44 patients were randomised to each treatment arm. None of the arms demonstrated an eight cycle completion rate (70.5/72.7/45.5% in arms A/B/C, respectively), which was statistically greater than 60% (P=0.102, P=0.056, P=0.982) which was our formal feasibility criteria, although only the completion rate in arm C was clearly worse than this level. The overall response rate (ORR) after carboplatin was 65.7% in 70 evaluable patients. In evaluable patients, ORRs after docetaxel-based cycles were: arm A 84.0% (21 out of 25); arm B 77.3% (17 out of 22); arm C 69.6% (16 out of 23). At follow-up (median 30 months), median progression-free survival times were: arm A 15.5 months (95% CI: 10.5-20.6); arm B 18.1 months (95% CI: 15.9-20.3); arm C, 13.7 months (95% CI: 12.8-14.6). Neutropenia was the predominant grade 3-4 haematological toxicity: 77.8/85.7/54.4% in arms A/B/C, respectively. Dyspnoea was markedly increased in both gemcitabine-containing arms (P=0.001) but was worse in arm C. Although just failing to rule out eight cycle completion rates less than 60%, within the statistical limitations of these small cohorts, the overall results for arms A and B are encouraging. Larger phase III studies are required to test these combinations.

"Dose dense" chemotherapy in ovarian cancer.

In essence, dose densification is "accelerated therapy" (a commonly used phrase in radiotherapeutics) and is a form of dose intensification because the amount of drug per unit time (dose intensity = mg/m(2)/week) is increased. There is general consensus that increasing platinum dose intensity in ovarian carcinoma has not been proven despite a dozen or more randomized trials evaluating up to twofold increases in dose intensity. Few randomized trials in ovarian carcinoma have compared weekly "dose dense" chemotherapy with more conventional dosing schedules although there are plenty of phase II studies. In these, dose densification of single agent therapy, for some drugs at least, appears to be relatively well tolerated, with encouraging levels of activity in patients purportedly refractory to the same agents when scheduled in the standard way. However, many studies ostensibly evaluating "dose density" do not actually evaluate this entity, but actually split the standard 3-weekly dose into weekly fragments thus maintaining the same dose intensity. Furthermore, as the aim of treatment in recurrent ovarian cancer is palliation, weekly treatments are less convenient, are probably less cost effective, and have different dose-limiting toxicities. This article will review the clinical data supporting dose density as a therapeutic maneuver in ovarian cancer.

Resistance to chemotherapy in advanced ovarian cancer: mechanisms and current strategies.

Although treatment for advanced epithelial ovarian cancer has improved over recent years with the introduction of taxane-platinum chemotherapy, the majority of patients will relapse, and in most the disease remains incurable. A thorough understanding of drug resistance mechanisms is needed, as this remains the largest obstacle in treating patients with recurrent disease. Multidrug resistance proteins, mismatch repair processes and alterations in the p53 pathway are examples of properties within tumour cells that may lead to drug resistance. Novel agents designed to circumvent these mechanisms (e.g. PSC 833, ONYX-015 and ADP53) are currently being investigated for ovarian cancer patients. Further improvements may result from the optimisation of existing first-line regimens with more creative schedules, perhaps involving sequential or intraperitoneal administration of existing drugs, and the incorporation of newer noncross-resistant drugs.