R.E.N. van Rijswijk

Dose intensity of MOPP chemotherapy and survival in Hodgkin's disease.

The association between dose intensity of chemotherapy with the rate of complete remission (CR), the duration of disease-free survival (DFS), and overall survival (OS) was separately analyzed for 67 patients initially treated with mechlorethamine, vincristine, procarbazine, and prednisone (MOPP), and for 75 patients in relapse following radiotherapy who had received MOPP as a salvage regimen. In both groups of patients, the fraction of the total dose of mechlorethamine delivered in all cycles divided by the planned dose for six cycles was strongly associated with OS (P = .002 for patients receiving initial MOPP and P = .02 for the salvage group, respectively). B symptoms were independent of drug-derived variables associated with OS (corresponding P values .03 for initial MOPP and .004 for the salvage group). The predictive value of mechlorethamine dosage with regard to OS was retained in an analysis restricted to the patients receiving greater than or equal to six cycles of chemotherapy. In the initial chemotherapy group, mechlorethamine dosage was associated with attainment of CR but none of the variables tested was predictive of DFS. In the salvage chemotherapy group, mechlorethamine dosage was associated with attainment of CR and duration of DFS as well. The results emphasize that, besides tumor characteristics, optimal dosage of chemotherapy is of great importance for survival.

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.

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.

The cellular composition in the peritoneal cavity and the cytotoxic function of the peritoneal cells from patients with ovarian cancer; effect of tumor necrosis factor-α treatment

In patients with epithelial ovarian cancer (EOC), the cellular composition in the peritoneal cavity and the functional capacities of the peritoneal cells (PC) are unknown. Especially the peritoneal macrophages (m phi) could play an important role in defense against tumor cells. To study the cellular composition in the peritoneal cavity and the functional capacities of PC, these cells were obtained from three patients with EOC. The PC were immunophenotyped and tested functionally in vitro in a cytotoxicity assay. One of the patients was treated intraperitoneally (i.p.) with a single dose of 0.06 mg/m2 tumor necrosis factor-alpha (TNF-alpha). PC were obtained before the treatment, after 24 h and after 1 week. PC from healthy women undergoing laparoscopic sterilization served as controls. It appeared that patients with EOC have a lower percentage of macrophages (m phi) in the peritoneal cavity than healthy persons. These m phi of patients were also less capable of killing U 937 tumor cells as compared to the peritoneal m phi of control persons. However, in the patient treated i.p. with TNF-alpha the cytotoxic capacities of the peritoneal m phi were strongly improved. The percentage cytotoxicity at an effector to target ratio of 10, increased from 17% to 80%. Thus, the peritoneal m phi in this patient were activated in vivo to a tumoricidal state. These findings indicate that PC in patients with EOC differ from controls, but further investigation is necessary to define the contribution of the disease and/or prior chemotherapy to this defect.

A double-blind randomized crossover study to compare the antiemetic efficacy of 250 mg with 500 mg methylprednisolone succinate (solu-medrol) as a single intravenous dose in patients treated with noncisplatin chemotherapy

A double-blind randomized crossover study was performed in 56 chemotherapy-naive patients, all receiving non-cisplatin-based chemotherapy, to compare the antiemetic effects of 2 doses of a single administration of methylprednisolone succinate (Solu-Medrol): 250 versus 500 mg. Among the 39 patients who satisfactorily completed both parts of the study, complete and major protection from emesis (0 and 1 emetic episode or only retching) was observed in 79% during the first course and in 69% during the second course. Treatment failure (> or = 6 episodes of vomiting) was observed in 18% during the first course and 21% during the second course. There was no significant difference between the two dose levels neither in terms of antiemetic protection nor in terms of the occurrence of side effects nor in patient preference. Most important side effects were facial flushing (45%), headache (22%) and facial edema (18%). It is concluded that, although a comparison with lower dosages cannot be made, within the dose range studied no clear dose-response relationship could be found.