Trivadi S. Ganesan

Phase I and Pharmacokinetic Study of PKC412, an Inhibitor of Protein Kinase C

PURPOSE N-Benzoyl staurosporine (PKC412) is a protein kinase C inhibitor with antitumor activity in laboratory models. We determined the toxicity of oral PKC412 administered daily for repeat cycles of 28 days. PATIENTS AND METHODS Thirty-two patients with advanced solid cancers were treated at seven dose levels (12.5 to 300 mg daily) for a total of 68 cycles. RESULTS The most frequent treatment-related toxicities were nausea, vomiting, fatigue, and diarrhea. At the two top dose levels (225 and 300 mg/d), 15 of 16 patients experienced nausea/vomiting (common toxicity criteria [CTC], version 1), grade 2 in nine of 16 and grade 3 in three of 16 patients; and six of 16 patients developed CTC grade 2 diarrhea. After 1 month of treatment, there were significant reductions in circulating lymphocyte (P <.02) and monocyte (P <.01) counts in patients receiving doses > or = 100 mg/d. Nevertheless, only two patients developed myelosuppression (both grade 2). Of two patients with progressive cholangiocarcinoma, one attained stable disease lasting 4.5 months and one a partial response lasting 4 months. There was a linear relationship between PKC412 dose and area under the curve (0-24 hours) and maximum plasma concentration with marked interpatient variability. The estimated median elimination half-life was 1.6 days (range, 0.9 to 4.0 days), and a metabolite with a median half-life of 36 days was detected. Steady-state PKC412 plasma levels at the top three dose cohorts (150 to 300 mg) were five to 10 times the cellular 50% inhibitory concentration for PKC412 of 0.2 to 0.7 micromol/L. CONCLUSION PKC412 can be safely administered by chronic oral therapy, and 150 mg/d is suitable for phase II studies. The pharmacokinetics and lack of conventional toxicity indicate that pharmacodynamic measures may be additionally needed to optimize the drug dose and schedule.

A phase II study of etanercept (Enbrel), a tumor necrosis factor alpha inhibitor in patients with metastatic breast cancer.

Purpose: Tumor necrosis factor (TNF) α is a key player in the tumor microenvironment and is involved in the pathogenesis of breast cancer. Etanercept is a recombinant human soluble p75 TNF receptor that binds to TNF-α and renders it biologically unavailable. In the current study, we sought to determine the toxicity, biological activity, and therapeutic efficacy of Etanercept in metastatic breast cancer. Experimental Design: We initiated a Phase II, nonrandomized, open-labeled study in patients with progressive metastatic breast cancer refractory to conventional therapy (Phase I toxicity data were available in patients with rheumatoid arthritis). Etanercept was administered subcutaneously at a dose of 25 mg twice weekly until disease progression. Results: Sixteen patients were recruited [median age 53 years (range, 34 to 74)]. A total of 141.6 weeks of therapy was administered (median of 8.1 weeks). Seven patients received ≥12 weeks of therapy. The most common side effects were injection site reactions (6), fatigue (5), loss of appetite (2), nausea (1), headache (1), and dizziness (1). Brief period of disease stabilization was seen in 1 patient lasting for 16.4 weeks. Immunoreactive TNF-α was elevated within 24 hours of therapy and persisted until the end of treatment (days 7, 28, 56, and 84). Phytohemagglutinin stimulates the production of interleukin-6 and CCL2 in peripheral blood cells, and the ability of Etanercept to modulate this response was assessed in a cytokine release assay. A consistent decrease in interleukin-6 and CCL2 level was seen compared with pretreatment values in serial blood samples (days 1, 7, 28, 56, and 84). Conclusions: Our study shows the safety and biological activity of Etanercept in breast cancer and provides data to assess pharmacodynamic endpoints of different schedules of Etanercept and combinations with chemotherapy or other biological therapies.

Study of Etanercept, a Tumor Necrosis Factor-Alpha Inhibitor, in Recurrent Ovarian Cancer

PURPOSE Convincing data support the link between inflammation and ovarian cancer. Tumor necrosis factor-alpha (TNF-alpha), a major mediator of inflammation, is chronically produced in the ovarian tumor microenvironment and may enhance tumor growth and invasion by inducing the secretion of cytokines, proangiogenic factors, and metalloproteinases. Etanercept is a recombinant human soluble p75 TNF receptor that binds to TNF-alpha and renders it biologically unavailable. In the current study, we sought to determine the toxicity, biologic activity, and therapeutic efficacy of etanercept in recurrent ovarian cancer. PATIENTS AND METHODS We initiated a phase I-B, nonrandomized, open-label study in patients with recurrent ovarian cancer. Etanercept was administered subcutaneously at a dose of 25 mg twice weekly (cohort one) and 25 mg thrice weekly (cohort two) until disease progression. RESULTS Thirty patients were recruited (cohort one, 17 patients; cohort two, 13 patients). Eighteen of the 30 patients (cohort one, 11 patients; cohort two, seven patients) completed > or = 12 weeks of treatment. Six patients achieved prolonged disease stabilization (cohort one, two patients [40 and 25 weeks]; cohort two, four patients [34, 24, 22, and 24 weeks]). A significant rise in immunoreactive TNF was seen in all patients (pretreatment compared with end of treatment). A phytohemagglutinin-stimulated whole-blood cytokine assay showed a significant fall in interleukin-6 (cohort one [11 of 17]) and CCL2 (cohort one [13 of 17]) levels. Common adverse effects were injection-site reactions and fatigue. CONCLUSION We provide evidence for the biologic activity and safety of etanercept in recurrent ovarian cancer. Our data suggest possible clinical activity that must be confirmed in future studies.

Inhibin as a marker for ovarian cancer

Inhibin is a polypeptide hormone produced by the granulosa cells of the ovary, and is present in body fluids as dimers of various sizes each comprising an alpha- and beta-subunit. Free forms of the alpha-subunit also circulate, and the presently available radioimmunoassay (Monash assay) cannot distinguish these from biologically active dimeric inhibin. Recently we described a new two-site enzyme immunoassay able for the first time to measure the levels of dimeric inhibin throughout the human menstrual cycle. The sensitivity limit of this assay is 2 pg ml-1 in human serum with cross-reactivity against activin of 0.05%. The normal range of inhibin in post-menopausal women is < 5 pg ml-1, in pre-menopausal women 2-80 pg ml-1 (2-10 pg ml-1 in the follicular phase, 40-80 pg ml-1 in the luteal phase). This assay was used to determine inhibin levels in sera from 15 (five pre-menopausal and ten post-menopausal) patients with granulosa cell tumours of the ovary. It was raised in a pre-menopausal patient preoperatively (261 pg ml-1), in six post-menopausal patients (32, 43, 54, 66, 24 and 58 pg ml-1) and one pre-menopausal patient with recurrent tumour, (237 pg ml-1), all confirmed clinically. Inhibin was normal in six patients in remission. Oestradiol levels were normal in all patients. Serial levels of inhibin predicted recurrence before overt clinical relapse in two patients. In 29 patients with malignant epithelial ovarian tumours inhibin levels were modestly elevated in nine and normal in the rest. Three patients with endometrioid histology, two with undifferentiated tumours, three with mucinous adenocarcinoma and one with clear cell carcinoma had elevated inhibin levels. Functional inhibin is secreted by all granulosa cell tumours of the ovary studied and can be used as a tumour marker to determine response to therapy and predict recurrence and is superior to oestradiol. A more detailed analysis of the levels of inhibin, and its subunits in epithelial ovarian cancer is needed to identify the molecular forms of the immunoreactive material before optimised assays can be applied to this more common tumour.

A Phase Ib trial of CA4P (combretastatin A-4 phosphate), carboplatin, and paclitaxel in patients with advanced cancer.

Background:The vascular disrupting agent combretastatin A4 phosphate (CA4P) causes major regression of animal tumours when given as combination therapy.Methods:Patients with advanced cancer refractory to standard therapy were treated with CA4P as a 10-min infusion, 20 h before carboplatin, paclitaxel, or paclitaxel, followed by carboplatin.Results:Combretastatin A4 phosphate was escalated from 36 to 54 mg m−2 with the carboplatin area under the concentration curve (AUC) 4–5, from 27 to 54 mg m−2 with paclitaxel 135–175 mg m−2, and from 54 to 72 mg m−2 with carboplatin AUC 5 and paclitaxel 175 mg m−2. Grade 3 or 4 neutropenia was seen in 17%, and thrombocytopenia only in 4% of 46 patients. Grade 1–3 hypertension (26% of patients) and grade 1–3 tumour pain (65% of patients) were the most typical non-haematological toxicities. Dose-limiting toxicity of grade 3 hypertension or grade 3 ataxia was seen in two patients at 72 mg m−2. Responses were seen in 10 of 46 (22%) patients with ovarian, oesophageal, small-cell lung cancer, and melanoma.Conclusion:The combination of CA4P with carboplatin and paclitaxel was well tolerated in the majority of patients with adequate premedication and had antitumour activity in patients who were heavily pretreated.

Role of lymphangiogenesis in cancer

Regional lymph node metastasis is a common event in solid tumors and is considered a marker for dissemination, increased stage, and worse prognosis. Despite rapid advances in tumor biology, the molecular processes that underpin lymphatic invasion and lymph node metastasis remain poorly understood. However, exciting discoveries have been made in the field of lymphangiogenesis in recent years. The identification of vascular endothelial growth factor ligands and cognate receptors involved in lymphangiogenesis, an understanding of the embryology of the mammalian lymphatic system, the recent isolation of pure populations of lymphatic endothelial cells, the investigation of lymphatic metastases in animal models, and the identification of markers that discriminate lymphatics from blood vessels at immunohistochemistry are current advances in the field of lymphangiogenesis, and as such are the main focus of this article. This review also evaluates evidence for lymphangiogenesis (ie, new lymphatic vessel formation in cancer) and critically reviews current data on the prognostic significance of lymphatic vascular density in tumors. A targeted approach to block pathways of lymphangiogenesis seems to be an attractive anticancer treatment strategy. Conversely, promotion of lymphangiogenesis may be a promising approach to the management of treatment-induced lymphedema in cancer survivors. Finally, the implications of these developments in cancer therapeutics and directions for future research are discussed.

Allele loss on chromosome arm 6q and fine mapping of the region at 6q27 in epithelial ovarian cancer.

Genetic changes have been shown to be important in determining the multistep progression of cancer. Allele loss studies and karyotypic analysis of epithelial ovarian tumours have indicated the presence of putative tumour suppressor genes on chromosomes 6, 11, 13, 17, 18, 22, and X. We have focused on chromosome arm 6q to identify the minimal region that may contain a putative tumour suppressor gene. Nineteen polymorphic microsatellite markers from 6q and one centromeric marker (D6S294) have been used to detect allele loss in 68 ovarian tumours (six benign, six borderline, and 56 with malignant histology). Allele loss was evaluated by separation of fluorescence labelled polymerase chain reaction‐amplified products. Forty‐six of fifty‐six (82%) malignant tumours showed allele loss on 6q, whereas only four of 56 had lost all the markers tested. Forty‐one of fifty‐six (73%) malignant tumours showed allele loss at 6q26‐27. The minimal region of allele loss was between markers D6S264 and D6S297 (3 cM), with maximal allele loss of 62% at D6S193 and 52% at D6S297. Three tumours showed loss of D6S193 only, while retaining flanking informative markers. Allele loss around 6q26‐27 was observed in all histological types of epithelial ovarian cancer and did not correlate with any clinical factors. In addition, there was allele loss at ESR (56%) and D6S286 (47%), though a minimal region was not defined. Allele loss at 6q12‐25 correlated significantly with endometrioid and mucinous ovarian malignant tumours (P = 0.01). The physical mapping of the region between D6S297 and D6S264 will allow the eventual identification of the putative tumour suppressor gene. Genes Chromosom Cancer 15:223–233 (1996).

The genetic analysis of ovarian cancer

Ovarian cancer represents the fifth most significant cause of cancer-related death for women and the most frequent cause of death from gynaecological neoplasia in the Western world. The incidence of ovarian cancer in the UK is over 5000 new cases every year, accounting for 4275 deaths per year (Chang et al., 1994). A recent meta-analysis of all randomised trials of patients with epithelial ovarian cancer after surgery demonstrated an overall 5 year survival of 30% (Advanced Ovarian Cancer Trialists Group, 1991). Five year survival rates are as follows: stage I, 70%; stage II, 45%; stage III, 17%; and stage IV, 5% (Chang et al., 1994). The high overall mortality is due to the majority of patients presenting with stage III and IV disease. Clearly, any methods that enable the early detection of ovarian cancer would lead to a significant decrease in mortality. Ovarian cancer encompasses a broad spectrum of lesions, ranging from localised benign tumours and tumours of borderline malignant potential, through to invasive malignant adenocarcinomas. Histologically, the common epithelial ovarian cancers, which account for 90% of all ovarian cancer, are classified into several types, that is serous, mucinous, endometrioid, clear cell, Brenner, mixed epithelial and undifferentiated tumours. The different histological subtypes reflect the considerable differentiation potential of the ovarian surface epithelium. The aetiology of ovarian cancer is not completely understood, although both epidemiological and genetic associations have been recorded. Epidemiological factors related to ovulation seem to be important (Fathalla, 1971), whereby ovarian epithelial cells undergo several rounds of division and proliferative growth to heal the wound in the epithelial surface, thereby increasing the chance of a genetic accident during the repair process, such as the activation of an oncogene or the inactivation of a tumour-suppressor gene (Berek et al., 1993). The genetic changes occurring in epithelial ovarian cancer are also poorly understood and, except for the analysis of the p53 gene, the majority have not yet been defined. This review focuses on the current understanding of cytogenetic abnormalities, linkage and allele loss studies that signpost chromosomal regions which may contain relevant genes. The emphasis of this review is on recessively acting rather than dominant genes (reviewed recently in Berchuck et al., 1992) as the isolation of tumoursuppressor genes will lay the foundation for an improved understanding of the mechanisms involved in tumorigenesis.

A phase II study of bryostatin 1 in metastatic malignant melanoma

Bryostatin 1 is a protein kinase C partial agonist which has both antineoplastic and immune-stimulatory properties, including the induction of cytokine release and expansion of tumour-specific lymphocyte populations. In phase I studies, tumour responses have been observed in patients with malignant melanoma, lymphoma and ovarian carcinoma. The dose-limiting toxicity is myalgia. Sixteen patients (age 35-76 years, median 57 years) with malignant melanoma were treated. All had received prior chemotherapy. In each cycle of treatment, patients received bryostatin 25 degrees g m(-2) weekly for three courses followed by a rest week. The drug was given in PET diluent (10 microg bryostatin ml(-1) of 60% polyethylene glycol, 30% ethanol, 10% Tween 80) and infused in normal saline over 1 h. The principal toxicities were myalgia (grade 2, eight patients and grade 3, six patients) and grade 2 phlebitis (four patients), fatigue (three patients) and vomiting (one patient). Of 15 patients evaluable for tumour response, 14 developed progressive disease. One patient developed stable disease for 9 months after bryostatin treatment. In conclusion, single-agent bryostatin appears ineffective in the treatment of metastatic melanoma in patients previously treated with chemotherapy. It should, however, be investigated further in previously untreated patients.

Phase I trial of the selective mitochondrial toxin MKT 077 in chemo-resistant solid tumours

BACKGROUND MKT077 is a rhodacyanine dye analogue which preferentially accumulates in tumour cell mitochondria. It is cytotoxic to a range of tumours. In this phase I study, MKT077 was administered as a five-day infusion once every three weeks. PATIENTS AND METHODS Ten patients, median age 59 (38-70) years, with advanced solid cancers were treated at three dose levels: 30, 40 and 50 mg/m2/day for a total of 18 cycles. 31Phosphorus magnetic resonance spectroscopy (MRS) was used to evaluate the effect of MKT077 on skeletal muscle mitochondrial function. RESULTS The predominant toxicity was recurrent reversible functional renal impairment (grade 2, two patients). One patient with renal cancer attained stable disease and the remainder progressive disease. There were no MRS changes in the first or second treatment cycles but one patient received 11 treatment cycles and developed changes consistent with a mitochondrial myopathy. Mean values for all pharmacokinetic parameters were at sub micromolar levels and did not exceed IC50 values (> or = 1 microM). CONCLUSIONS Because of the renal toxicity, and animal studies showing MKT077 causes eventual irreversible renal toxicity, further recruitment was halted. The study shows, however, that it is feasible to target mitochondria with rhodacyanine analogues, if drugs with higher therapeutic indices could be developed.