Phase II study on 9-nitrocamptothecin (RFS 2000) in patients with advanced or metastatic urothelial tract tumors

OBJECTIVE: To investigate the antitumor activity and the safety of RFS2000, an oral topoisomerase I inhibitor, in patients with advanced or metastatic urothelial tract tumors refractory to one prior chemotherapy regimen. PATIENTS AND METHODS: Eligible patients were to have failed first line treatment for advanced or metastatic disease. Patients received RFS2000 as one daily oral intake at the dose of 1.5 mg/m(2)/day according to a "5 days on/2 days" off schedule continuously. One cycle was arbitrarily defined as a 3 week period. Sufficient oral fluid intake to prevent cystitis previously described in phase I trials with RFS2000 was recommended. Gehan design was used for sample size determination. Anti-tumor activity was evaluated according to the RECIST criteria and toxicity according to CTC version 2. RESULTS: Twenty patients received a total of 57 cycles (range 1-8). Grade 3-4 toxicity was observed in 10 patients requiring dose or schedule modifications. Hematological grade 3-4 toxicity was observed in 16% of the cycles. Only one patient experienced a partial response. CONCLUSIONS: RFS2000 could be administered orally as a "5 days on/2 days off" schedule continuously with a median dose intensity of 90.6% with an acceptable toxicity profile. However, RFS2000 did not exert significant activity in patients with advanced/metastatic urothelial tract tumors failing prior chemotherapy. The results of this study do not suggest further investigation of RFS2000 at the present dose and schedule for the treatment of urothelial tract tumors in this refractory population.     

Operationalization of biopsychosocial case complexity in general health care: the INTERMED project

OBJECTIVE: Lack of operationalization of the biopsychosocial model hinders its effective application to the increasingly prevalent problems of comorbidities in clinical presentations. Here, we describe the INTERMED, an instrument to assess biopsychosocial case complexity in general health care, and provide an overview of its psychometric evaluation. METHOD: Review and summary of our publications to date, and re-analysis of findings. RESULTS: The INTERMED has face-validity, is brief and easy to use, and several research reports support its reliability and validity. It has the capacity to detect patients at risk for poor clinical outcome and quality of life. CONCLUSIONS: The INTERMED project is relevant to various agents involved in the care process. It provides a basis for effective multidisciplinary treatment of patients with a high case complexity.     

Population pharmacokinetics of cyclophosphamide and its metabolites 4-hydroxycyclophosphamide, 2-dechloroethylcyclophosphamide, and phosphoramide mustard in a high-dose combination with Thiotepa and Carboplatin

The anticancer prodrug cyclophosphamide (CP) is activated by the formation of 4-hydroxycyclophosphamide (4OHCP), which decomposes into phosphoramide mustard (PM). This activation pathway is inhibited by thiotepa. CP is inactivated by formation of 2-dechloroethylcyclophosphamide (2DCECP). The aim of this study was to develop a population pharmacokinetic model describing the complex pharmacokinetics of CP, 4OHCP, 2DCECP, and PM when CP is administered in a high-dose combination with thiotepa and carboplatin. Patients received a combination of CP (1000-1500 mg/m/d), carboplatin (265-400 mg/m/d), and thiotepa (80-120 mg/m/d) administered in short infusions over 4 days. Twenty blood samples were collected per patient per course. Concentrations of CP, 4OHCP, 2DCECP, PM, thiotepa, and tepa were determined in plasma. Using NONMEM, an integrated population pharmacokinetic model was used to describe the pharmacokinetics of CP, 4OHCP, 2DCECP, and PM, including the already described processes of autoinduction of CP and the interaction with thiotepa. Data were available on 35 patients (70 courses). The pharmacokinetics of CP were described with a 2-compartment model, and those of 4OHCP, 2DCECP, and PM with 1-compartment models. Before onset of autoinduction, it was assumed that CP is eliminated through a noninducible pathway accounting for 20% of total CP clearance, whereas 2 inducible pathways resulted in formation of 4OHCP (75%) and 2DCECP (5%). It was assumed that 4OHCP was fully converted to PM. Induction of CP metabolism was mediated by 2 hypothetical amounts of enzyme whose quantities increased in time in the presence of CP (kenz=0.0223 and 0.0198 hours). Induction resulted in an increased formation of 4OHCP (approximately 50%), PM (approximately 50%), and 2DCECP (approximately 35%) during the 4-day course, and concomitant decreased exposure to CP (approximately 50%). The formation of 2DCECP was not inhibited by thiotepa. Apparent volumes of distribution of CP, PM, and 2DCECP could be estimated being 43.7, 55.5, and 18.5 L, respectively. Exposure to metabolites varied up to 9-fold. The complex population pharmacokinetics of CP, 4OHCP, 2DCECP, and PM in combination with thiotepa and carboplatin has been established and may form the basis for further treatment optimization with this combination.     

Aprepitant inhibits cyclophosphamide bioactivation and thiotepa metabolism

Background: Patients receiving the highly emetogenic high-dose chemotherapy regimen with cyclophosphamide, thiotepa and carboplatin (CTC) may benefit from the neurokin-1 receptor antagonist aprepitant in addition to standard anti-emetic therapy. As aprepitant has been shown to be a moderate inhibitor of the cytochrome P450 (CYP) 3A4 isoenzyme, its effect on the pharmacokinetics and metabolism of cyclophosphamide and thiotepa was evaluated. Moreover, preliminary results on the clinical efficacy of aprepitant in the CTC regimen are reported. Patients and methods: Six patients were enrolled in a protocol that employed a 4-day course of CTC high-dose chemotherapy with cyclophosphamide (1,500 mg/m²/day), thiotepa (120 mg/m²/day) and carboplatin (AUC 5 mg min/ml/day). Two patients received the tCTC protocol, which comprises two-third of the dose of CTC. In addition to standard anti-emetic therapy, the patients received aprepitant from one day before the start of their course until 3 days after chemotherapy. Blood samples were collected on days one and three of the course and analyzed for cyclophosphamide and its activated metabolite 4-hydroxycyclophosphamide, thiotepa and its main active metabolite tepa. The influence of aprepitant on the pharmacokinetics of cyclophosphamide and thiotepa was analyzed using a population pharmacokinetic analysis including a reference population of 49 patients receiving the same chemotherapy regimen without aprepitant and sampled under the same conditions. The frequency of nausea and vomiting in the six patients receiving CTC was compared with those of the last 22 consecutive patients receiving CTC chemotherapy without aprepitant. Inhibitory activity of aprepitant on cyclophosphamide and thiotepa metabolism was also tested in human liver microsomes. Results: In our patient population, the rate of autoinduction of cyclophosphamide (P=0.040) and the formation clearance of tepa (P<0.001) were reduced with 23% and 33% when aprepitant was co-administered, respectively. Exposures to the active metabolite 4-hydroxycyclophosphamide and tepa were therefore reduced (5% and 20%, respectively) in the presence of aprepitant. In human liver microsomes, the 50% inhibitory concentrations (IC₅₀) of aprepitant for inhibition of cyclophosphamide (IC₅₀=1.3 g/ml) and thiotepa (IC₅₀=0.27 g/ml) metabolism were within the therapeutic range. Patients receiving aprepitant experienced less frequently CINV both during and after the CTC course compared with the reference population (nausea 3.7 days vs. 5.8 days, P=0.052; vomiting 0.5 days vs. 4.8 days, P<0.001). Conclusion: Aprepitant inhibited both cyclophosphamide and thiotepa metabolism, most probably due to inhibition of the CYP 3A4 and/or 2B6 isoenzymes. The effects of this interaction are, however, small compared to the total variability. Addition of aprepitant may provide superior protection against vomiting in patients receiving the highly emetogenic high-dose CTC chemotherapy.     

Overexpression of arginase alters circulating and tissue amino acids and guanidino compounds and affects neuromotor behavior in mice

Arginine is an intermediate of the ornithine cycle and serves as a precursor for the synthesis of nitric oxide, creatine, agmatine and proteins. It is considered to be a conditionally essential amino acid because endogenous synthesis only barely meets daily requirements. In rapidly growing suckling neonates, endogenous arginine biosynthesis is crucial to compensate for the insufficient supply of arginine via the milk. Evidence is accumulating that the intestine rather than the kidney plays a major role in arginine synthesis in this period. Accordingly, ectopic expression of hepatic arginase in murine enterocytes by genetic modification induces a selective arginine deficiency. The ensuing phenotype, whose severity correlates with the level of transgene expression in the enterocytes, could be reversed with arginine supplementation. We analyzed the effect of arginine deficiency on guanidine metabolism and neuromotor behavior. Arginine-deficient transgenic mice continued to suffer from an arginine deficiency after the arginine biosynthetic enzymes had disappeared from the enterocytes. Postweaning catch-up growth in arginine-deficient mice was characterized by increased levels of all measured amino acids except arginine. Furthermore, plasma total amino acid concentration, including arginine, was significantly lower in adult male than in adult female transgenic mice. Decreases in the concentration of plasma and tissue arginine led to significant decreases in most metabolites of arginine. However, the accumulation of the toxic guanidino compounds, guanidinosuccinic acid and methylguanidine, corresponded inversely with circulating arginine concentration, possibly reflecting a higher oxidative stress under hypoargininemic conditions. In addition, hypoargininemia was associated with disturbed neuromotor behavior, although brain levels of toxic guanidino compounds and ammonia were normal.     

Developments in chemotherapy; cytostatic agents with an increased specificity and other forms of administering cytotoxic antineoplastic agents]

In recent years developments in molecular biology have greatly increased our knowledge about the cellular processes which govern the development of cancer. This has led to the development of anticancer agents that specifically target one of these cellular processes, for example, farnesyl transferase inhibitors, receptor tyrosine kinase inhibitors, matrix metalloproteinase inhibitors and anti-angiogenic agents. In addition to this, new chemotherapeutic agents with increased target specificity have been developed. Finally, in recent years there has been an emphasis on developing new forms of administration so that optimal use can be made of existing chemotherapeutic agents.     

Predicting response to neoadjuvant chemotherapy in patients with cervical carcinoma: can we do without any longer?

Abstract. de Jonge ETM, Lindeque BG, Burger W, Nesland JM, Holm R. Predicting response to neoadjuvant chemotherapy in patients with cervical carcinoma: can we do without any longer?
The aim of the study was to identify variables that may predict the response to neoadjuvant chemotherapy (NACT) in patients with cervical cancer as maturing data from the literature indicate that this therapeutic strategy might be beneficial to some but harmful to others. Clinico-pathologic variables including age, histology, tumor differentiation, as well as immunohistochemical overexpression of p53, mdm2, c-erbB-2, and cathepsin D in 37 of these patients were evaluated as possible predictors of response to the NACT. Fifty-five patients with stage IIB cervical cancer submitted to two courses of cisplatin/ifosfamide/mesna prior to definitive treatment with radical surgery or radiation therapy were the subjects of this study.
The clinical response rate was 80% but none of the variables was able to predict response to NACT. Unless methods are found enabling us to predict response and therefore to identify those patients that could benefit from including NACT in the treatment of locally advanced cervical cancer, only women with primarily resectable tumors should be selected for this multimodality approach as a result of the possibility of cross-resistance with radiation therapy in nonresponders.