J. Wagstaff

Prognostic role of clinical, pathological and biological characteristics in patients with locally advanced breast cancer.

Forty-two patients with clinical stage IIIA or IIIB breast cancer were treated with neoadjuvant chemotherapy followed by mastectomy and radiotherapy. The median follow-up was 32 months (range 10-72 months) and the median time to progression was 17 months (range 10-30 months). A multivariate analysis showed that a longer disease-free survival (DFS) was related to more chemotherapy cycles given (P = 0.003), a better pathological response to chemotherapy (P = 0.04) and fewer positive axillary lymph nodes (P = 0.05). A better overall survival (OS) was related to more chemotherapy cycles given (P = 0.03) and better pathological response to chemotherapy (P = 0.04). In patients with residual tumour after neoadjuvant chemotherapy, high levels of staining for Ki-67 was correlated with a worse DFS (P = 0.008). Other biological characteristics, including oestrogen receptor status, microvessel density (CD31 staining), P-glycoprotein (P-gp) staining and nuclear accumulation of p53, were not independent prognostic factors for either DFS or OS. If both P-gp and p53 were expressed, DFS and OS were worse in the uni- and multivariate analysis. The preliminary results of this phase II study suggest that coexpression of P-gp/p53 and a high level of staining for Ki-67 after chemotherapy are associated with a worse prognosis, and that prolonged neoadjuvant chemotherapy and the attainment of a pathological complete remission are important factors in determining outcome for patients with this disease.

A phase I study of recombinant interferon gamma administered by s.c. injection three times per week in patients with solid tumours.

SummaryHuman recombinant DNA interferon gamma (IFN-G), with a specific activity of 2×106 IU/mg protein, was administered s.c. 3 days per week for 2 months to patients with solid tumors. The maximum tolerated dose (MTD) was 10×106 IU/m2 (5.0 mg/m2) per injection, and six patients were treated at the MTD. Two of these ceased treatment because of severe subjective toxity (headache, rigors and pyrexia) and three patients developed WHO grade 3 leucopenia. Subjective toxicity varied considerably between patients and some patients at low dose levels experienced severe constitutional symptoms whilst others treated at the MTD had few side effects. These differences were unrelated to pharmacokinetic parameters. Bioavailability of this IFN-G administered s.c. was very variable from one patient to another at the same dose level. We therefore counsel caution in using this IFN-G preparation s.c. in phase II studies.

Continuous infusion or subcutaneous injection of granulocyte-macrophage colony-stimulating factor: increased efficacy and reduced toxicity when given subcutaneously

Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a haematopoietic growth factor with a wide variety of applications in the clinic. In early phase I studies the continuous intravenous (c.i.) route of administration was often used. Later it was shown that subcutaneous (s.c.) administration was also effective. The optimal route of administration remains, however, poorly defined, and no studies have made a direct comparison between these two routes of administration. We treated patients with advanced breast cancer with moderately high-dose doxorubicin and cylophosphamide and GM-CSF. The first 14 patients received GM-CSF by c.i, while subsequently 47 patients received it s.c. Comparison between the two groups showed that c.i. GM-CSF was more toxic in several respects. There was a higher need for erythrocyte and platelet transfusions and a significant deterioration in the performance status. This study indicates that subcutaneous GM-CSF is the preferred route of administration. Randomised trials are, however, needed to confirm these conclusions.

Suramin : rapid loading and weekly maintenance regimens for cancer patients

PURPOSE Suramin is an anticancer agent with a narrow therapeutic window and a terminal half-life of 45 to 55 days. These characteristics make it necessary to control accurately the serum concentrations of the drug. Therefore, the aim of the present study was to develop a rapid loading regimen, followed by weekly administration of suramin to maintain serum concentrations of between 150 and 300 micrograms/mL for 8 weeks. PATIENTS AND METHODS Eligible patients were treated with five different loading regimens. Initially, weekly maintenance doses were estimated manually by the treating physician. Subsequently, computer-assisted dosing that used Bayesian pharmacokinetic modeling was used. RESULTS Thirty-eight courses of suramin that were administered to 35 patients were studied. The optimal loading regimen consisted of a continuous infusion of 600 mg/m2 during a 24-hour period, which resulted in a mean serum concentration of 319 micrograms/mL. Potentially toxic concentrations that were observed with shorter infusions were avoided. Maintenance treatment, which used the weekly administration of suramin during a 6-hour period, seemed to be able to maintain mean suramin serum trough concentrations of 150 micrograms/mL, while preventing mean peak concentrations of more than 300 micrograms/mL. The use of Bayesian pharmacokinetics was superior to manual estimation in tailoring the optimal dose to the therapeutic window. CONCLUSIONS Continuous infusion is the optimal way of delivering suramin during the loading phase. To maintain trough levels and peak levels within a narrower therapeutic window, suramin will have to be administered more frequently than once a week. Bayesian modeling based on individual serum levels and population pharmacokinetics allows accurate dosing to maintain suramin levels within the therapeutic window.

Multiple cycles of high-dose doxorubicin and cyclophosphamide with G-CSF mobilized peripheral blood progenitor cell support in patients with metastatic breast cancer

BACKGROUND In a previous study we applied doxorubicin and cyclophosphamide in a dose-intensive regimen with GM-CSF to patients with metastatic breast cancer (MBC). That treatment failed to prolong the remission duration compared to conventional-dose chemotherapy. In the present study we escalated the dosages of the same agents to: 1) determine the maximum tolerated dosages (MTD) when given for three cycles with G-CSF mobilised peripheral blood progenitor cell (PBPC) reinfusion and 2) evaluate the antitumour effect of this regimen. PATIENTS AND METHODS For mobilisation of PBPC, G-CSF 15 microg/kg/day was given subcutaneously (s.c.), and in subsequent cohorts leucapheresis was started on days 3, 4 or 6. The intention was to treat MBC patients with three cycles of doxorubicin and cyclophosphamide at a starting dose of doxorubicin 90 mg/m2 and cyclophosphamide 1000 mg/m2. Dosages were then escalated in subsequent cohorts of at least three patients. In case of dose-limiting mucositis, only the dose of cyclophosphamide was escalated in the next cohort. RESULTS Twenty-one patients entered this protocol, of which 18 patients received high-dose chemotherapy. The mobilisation of PBPC using G-CSF only was sufficient for three cycles of high-dose chemotherapy in 10 of 21 (47%) patients. Mucositis precluded dose escalation of doxorubicin beyond 110 mg/m2. The MTD in this combination was 110 mg/m2 for doxorubicin, and 4 g/m2 for cyclophosphamide, with haemorrhagic cystitis being the dose-limiting toxicity. The overall response rate was 78% (95% confidence interval (95% CI): 57%-97%), with 22% (95% CI: 3%-41%) complete responses. CONCLUSION The MTD of this three cycle high-dose regimen was doxorubicin 110 mg/m2 and cyclophosphamide 4 g/m2 with mucositis and cystitis being dose-limiting toxicities. Although the primary aim was not the evaluation of antitumour effect, this high-dose regimen does not appear to provide an improvement of treatment results in comparison with our previous study with the same drugs at moderately high-dosages without stem cell support.

Management of stage III breast Cancer

Stage III breast cancer encompasses a heterogenous group of patients. According to the American Joint Committee on Cancer (AJCC) these tumors include stage IIIA and stage IIIB disease, the first generally being operable but the second inoperable. Patients with inflammatory breast cancer are also included in stage IIIB disease, and these patients have the worst prognosis. Multidisciplinary therapy has become the treatment of choice for these patients. Primary or neoadjuvant chemotherapy, followed by locoregional therapy, either surgery, radiotherapy or both, is now an accepted strategy. Most patients achieve a response to chemotherapy, resulting in downstaging of the tumor, and 5-year-survival rates have improved from 10–20% with local therapy alone to 30–60% with the multidisciplinary approach. Although many prospective, mainly phase II trials have been performed in stage III breast cancer, the optimal treatment scheme still has to be established. The role of new therapeutic strategies such as high-dose chemotherapy with hematopoietic stem cell rescue and higher dose intensity regimens with hematopoietic growth factors is currently under investigation. This article will review the literature and discuss our own research in this area.

The synergistic and antagonistic effects of cytotoxic and biological agents on the in vitro antitumour effects of suramin

Suramin has shown antitumour activity in vitro and in vivo. At plasma levels higher than 200 microM there is, however, excessive toxicity. We have, therefore, attempted to improve the antitumour effects of suramin in vitro by combining it with several other antitumour agents. The MCF-7 mammary carcinoma and PC3 prostate cancer cell lines were exposed continuously to suramin and the other agents for 6 days. The sulphorhodamine B (SRB) assay was used for the assessment of growth inhibition. The dose-response interactions were evaluated using the median-effect analysis with the Chou and Talalay computer programme. In the MCF-7 cell line, the combination of suramin plus doxorubicin (DXR), cisplatin (CDDP), 5-fluorouracil (5-FU) or tumour necrosis factor (TNF) resulted in synergistic growth inhibition, whilst its combination with miltefosine (HPC) was antagonistic. In the PC-3 cell line, suramin plus CDDP or TNF was synergistic, whilst its combination with DXR, 5-FU and HPC was antagonistic. All tested combinations with interferon-alpha (IFN-alpha), interferon-gamma (IFN-gamma) and with the combination of both IFN-alpha+IFN-gamma were not synergistic. The synergistic effect of suramin with DXR was schedule dependent. Pretreatment (addition of DXR on day 1 and suramin on days 2-5) was additive at the IC50 level, in both cell lines. Addition of DXR at day 5 was more effective than simultaneous exposure. We found a synergistic effect for the combination of suramin with CDDP and TNF in both cell lines. In addition the combination with DXR and 5-FU was synergistic in MCF-7. Sequential administration of DXR-suramin or suramin-DXR increased the growth inhibition.