The antiproliferative action of a melphalan hexapeptide with collagenase-cleavable site

Purpose: The objective of the present study was to examine the relevance of collagenase in the antitumor action of a melphalan peptide (MHP) with a collagenase-cleavable sequence. The question was addressed as to whether collagenase may act as an activator or a target in the antiproliferative mechanism of MHP. Methods: Melphalan was inserted into peptides representing the sequence Pro-Gln-Gly-Ile-Ala.Gly of the collagenase-cleavable site in collagens. Changes in growth and collagenase IV activities of HT-1080, HT-29, HT-168, and MCF-7 cell cultures were investigated. Results: The present investigations provide data indicating that Pro-Gln-Gly-Ile-Mel-Gly (melphalan hexapeptide, MHP) is a substrate for both bacterial and 72-kDa type IV collagenases and that in this way it can generate Ile-Mel-Gly (melphalan tripeptide, MTP) of higher cytotoxic potency. Indeed, the formation of MTP was detected in the conditioned medium of HT-1080, a collagenase IV-producing human fibrosarcoma. In a comparison of equimolar concentrations of melphalan and its two peptide derivatives (MHP and MTP), superior antiproliferative action of MTP was seen in HT-29, HT-1080, and HT-168 tumor cell cultures. However, the relatively modest cytostatic actions of MHP were increased when bacterial collagenase was added to the cell cultures. After melphalan treatment, reduced levels of both 92 and 72-kDa type IV collagenases were seen in the HT-1080 cell cultures. However, the reduction of collagenase activity and the cell counts did not run parallel in the MTP- or MHP-treated cultures; indeed, collagenase activity related to cell numbers showed an elevated level. Conclusions: As the conversion of MHP to the more toxic MTP was detected in the presence of collagenases, it is possible that collagenase-directed activation of prodrugs may be a promising approach for the development of more selective cytostatic drugs against malignant tumors with high collagenase activities. Received: 6 October 1996 / Accepted: 22 July 1997     

Enhancement of Transport of D-Melphalan Analogue by Conjugation with L-Glutamate across Bovine Brain Microvessel Endothelial Cell Monolayers

Abstract

In this paper, the L-glutamate (L-Glu) transport system was targeted to improve the delivery of a model compound, p-di(hydroxyethyl)-amino-D-phenylalanine (D-MOD), through the blood-brain barrier (BBB) in vitro cell culture model. D-MOD is an analogue of an antitumor agent D-melphalan. To target the L-Glu transport system, D-MOD was conjugated to L-Glu to give D-MOD-L-Glu conjugate. D-MOD and D-MOD-L-Glu transport properties were evaluated using the bovine brain microvessel endothelial cell (BBMEC) monolayers. The results suggest that D-MOD-L-Glu conjugate permeates through the BBMEC monolayers more readily than the parent D-MOD. The improvement of transport may be due to the recognition of D-MOD-L-Glu by the L-Glu transport system. The transport mechanism was evaluated using several different experiments including: (a) concentration-dependent studies; (b) temperature-dependent studies; (c) substrate inhibition studies; and (d) metabolic inhibitor studies. The D-MOD-L-Glu transport was inhibited by the change of temperature from 37°C to 4°C. At higher concentrations, the transport of D-MOD-L-Glu reached plateau due to saturation. Furthermore, some amino acids (i.e., L-Glu, L-Asp, D-Asp, and L-Gln) inhibited the transport of D-MOD-L-Glu; presumably the conjugate was competing with these amino acids for the same transport system. Metabolic inhibitors (i.e., 2,4-dinitrophenol and sodium azide) suppressed the transport of the conjugate. However, the conjugate was not transported by monocarboxylic acid, dipeptide and neutral amino acid transporters. In conclusion, the L-Glu transport system can be utilized to facilitate a non-permeable drug across the BBB by conjugating the drug with L-Glu amino acid.     

Second malignancies in multiple myeloma; emerging patterns and future directions

The changing landscape of treatment options for multiple myeloma has led to a higher proportion of patients achieving deep, long-lasting responses to therapy. With the associated improvement in overall survival, the development of subsequent second malignancies has become of increased significance. The risk of second malignancy after multiple myeloma is affected by a combination of patient-, disease- and therapy-related risk factors. This review discusses recent data refining our knowledge of these contributing factors, including current treatment modalities which increase risk (i.e. high-dose melphalan with autologous stem cell transplant and lenalidomide maintenance therapy). We highlight emerging data towards individualized risk- and response-adapted treatment strategies and discuss key areas requiring future research.     

Combination chemotherapy with mitomycin C,vindesine and melphalan for refractory metastatic breast cancer

Summary A combination of mitomycin C, vindesine and melphalan was administered to 33 patients with heavily pretreated refractory breast cancer. The overall response rate was 27% with a mean duration of more than 10.2 months. A stabilization with a mean duration of 5.1 months was seen in 56% of cases, while 20% of patients progressed. Gastrointestinal toxicity, mostly grade 1 or 2 nausea/vomiting was seen in 85% of cases, grade 1 or 2 leukopenia in 60% of patients, and grade 1 or 2 thrombocytopenia in 42%. Considering the good compliance of this regimen and the poor prognosis of patients with refractory advanced breast cancer, this combination can be useful as a palliative treatment of breast carcinoma.Abbreviations MMC mitomycin C - VDS vindesine - L-PAM melphalan     

马法兰预处理行自体外周血造血干细胞移植患儿的护理

目的 总结14例以马法兰预处理行自体外周血造血干细胞移植患儿的护理特点.方法 根据儿童的生理特点行移植前的各项准备,并放置双通道中心静脉插管.预处理方案采用卡铂和足叶乙甙24 h持续静脉滴注,加马法兰,连用4 d.结果 经中心静脉双通道持续静滴化疗药物4 d,未发生渗漏等现象,耐受性好;均发生了感染、较严重的消化道反应及严重的口腔黏膜溃烂水肿,均伴有严重的孤独感和心理负担.通过加强无菌观念,做好口腔护理、肛周护理等基础护理工作,并重视心理护理14例患儿的各种并发症均痊愈,移植成功.结论 中心静脉插管有利于顺利实施连续4 d的化疗,用马法兰等预处理的移植患儿伴有十分严重的并发症,认真细致的护理至关重要.     

Thermal enhancement of melphalan and oxaliplatin cytotoxicity in vitro

It has been established that hyperthermia can enhance cytotoxicity of some chemotherapeutic agents. This has led to various clinical trials of thermochemotherapy, although many questions remain unanswered. The effects of various agents have been studied on animal tumours with different histopathology at elevated temperatures. These studies indicated that alkylating agents were most effective to all tumours at a moderately elevated temperature. Cisplatin was also effective to all tumours, but its effectiveness at 41.5°C was less than that of alkylating agents. To quantitatively study these findings, the magnitude of thermal enhancement of melphalan, an alkylating agent, and that of oxaliplatin, a new platinum compound, were studied at 37-44.5°C by the colony formation assay. The dose of each agent was kept constant, and cell survival was determined as a function of treatment time. The cell survival curve was exponentially related with treatment time at all test temperatures, and the T 0 (the time to reduce survival from 1 to 0.37) decreased with an increasing temperature. These results suggested that the cytotoxic effect of these agents occurred with a constant rate at 37°C, and the rate was facilitated with an increasing temperature. This suggests that heat can accelerate the cytotoxic chemical reaction, leading to substantial thermal enhancement. The thermal enhancement ratio (TER, the ratio of the T 0 at 37°C to the T 0 at an elevated temperature) increased with an increase in the temperature. The activation energy for melphalan at moderately elevated temperatures was largest among the agents tested in the laboratory and that for oxaliplatin was approximately half of the melphalan activation energy. This suggests that the thermal enhancement for the cytotoxicity of melphalan or alkylating agents might be the greatest. Potential mechanisms of thermal enhancement of cytotoxicity were discussed.     

Population pharmacokinetics of melphalan,infused over a 24-hour period,in patients with advanced malignancies

Purpose The objective of the present study was to characterize the population pharmacokinetics of melphalan infused over a 24-h period in patients with advanced malignancies.Methods Enrolled in the study were 64 patients (144 courses). The population pharmacokinetic analysis was performed using NONMEM through the graphical interface Visual-NM. Population characteristics were computed from an initial group of 43 patients (99 courses), and 21 additional patients (45 courses) were used for model validation. With the use of a one-compartment model, the influence of demographic and biological characteristics was examined. The basic parameters were total clearance (CL) and volume of distribution (V). The interoccasion variability was taken into account in the model. The drug exposure was estimated for each patient and correlated with markers of efficacy and toxicity.Results Data analysis was performed using a three-step approach. In step 2, a close relationship was found between creatinine clearance, gender and melphalan CL. The inclusion of this second stage model significantly improved the fit. Melphalan CL was higher in male patients (14.3±4.5 l/h per m²) than in female patients (12.3±4.5 l/h per m²). CL was also reduced somewhat in patients with decreased creatinine clearance. Large interindividual variability in pharmacokinetic parameters occurred (CL varied from 4.4 to 30.6 l/h per m²). The percentage intrapatient variability in clearance between courses was 25.4%. For determining melphalan AUC in clinical routine from one sample drawn at steady state, Bayesian methodology allowed a more accurate estimation of CL than the classical formula. Neutropenia and thrombocytopenia were the main haematological toxicities encountered; grade 4 was observed in 34 and 22 courses over a total of 144 courses, respectively. No significant relationship between AUC and haematological toxicity was found. In patients with prostatic cancer a weak relationship was observed between the decrease in PSA levels and AUC (P=0.0457), while in patients with ovarian cancer no relationship was found between AUC and CA125 levels.Conclusion The population pharmacokinetic approach developed in this study should allow dosage to be individualized in order to decrease toxicity while maintaining good efficacy.     

Idarubicin containing regimen in multiple myeloma: preliminary results of a pilot study using a modified "TANDEM" transplant program

Tandem autologous transplant actually represents a challenge in multiple myeloma treatment, but the best conditioning regimen is still under investigation. With the aim of evaluating the feasibility of a modified tandem transplant strategy, we treated 10 multiple myeloma patients after conventional first line chemotherapy with a two step conditioning regimen consisting of high-dose melphalan (200 mg/m 2 ) followed by high-dose melphalan (180 mg/m 2 ) together with indarubicin (15 mg/sqm 2 c.i. ×3 days) both with peripheral stem cell support. At first transplant, the median age was 62 years, performance status was good and disease status was CR in 2 patients and PR in the rest. At the end of the first transplant, 70% of patients achieved CR and only mild toxicity was observed. After the second transplant further improvement of the response rate was obtained with 90% CR. However, we observed three toxic early infection-related deaths from CMV and legionella pneumonia at day +17, +26, +54 after transplantation. Although this schedule seems to be effective in terms of response rate, the 30% TRM imposes an anthracycline dose-reduction with careful patient selection. This approach could reduce the toxic effects and maintain the efficacy of therapy at the same time.     

Phase 2 Study of an Intravenous Busulfan and Melphalan Conditioning Regimen for Autologous Stem Cell Transplantation in Patients with Multiple Myeloma (KMM150)

This prospective study evaluated the efficacy and toxicity of intravenous busulfan and melphalan as a conditioning regimen for autologous stem cell transplantation (ASCT) in patients with multiple myeloma (MM). A total of 99 patients with MM, enrolled between January 2013 and March 2016, received intravenous busulfan (9.6?mg/kg) and melphalan (140?mg/m²) before ASCT. The median time to transplant was 6.2 months, and 90 (90.9%) patients underwent ASCT within 12 months of the diagnosis. The overall response rate after ASCT was 94.0%, including 43.5% with a stringent complete response/complete response, 27.3% with very good partial response, and 23.2% with partial response. The most common severe nonhematologic toxicity (grade 3 to 4) was infection (26.3%) and stomatitis (15.2%). Three (3.2%) patients developed veno-occlusive disease. No treatment-related mortality was observed. After a median follow-up of 26.1 months, the median progression-free survival was 27.2 months (range, 13.0 to 41.4 months) and median overall survival was not reached. In conclusion, a conditioning regimen of intravenous busulfan and melphalan was effective and tolerable.ClinicalTrials.gov. number: NCT01923935     

Hypercytokinemia-induced metabolic encephalopathy in a multiple myeloma patient on hemodialysis undergoing autologous stem cell transplantation: Clinical response after plasma exchange

We report here a 50-years old female with multiple myeloma-associated chronic renal failure who underwent high-dose chemotherapy supported by autologous hematopoietic stem cell transplantation. She developed progressive encephalopathy on day 5 progressing to coma despite hemodialysis and no obvious organ failure. She finally recovered after a single 1-liter plasma exchange. The final diagnosis was metabolic encephalopathy due to hypercytokinemia, particularly high serum TNF levels. We discuss here the pathogenesis and raise an alert for monitoring cytokine levels in patients with renal failure undergoing high-dose chemotherapy.