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M B Regazzi

Publications and source records attributed to M B Regazzi.

At least 19 recordsLinked to original sources
PubMed2002

A sequence of immuno-chemotherapy with Rituximab, mobilization of in vivo purged stem cells, high-dose chemotherapy and autotransplant is an effective and non-toxic treatment for advanced follicular and mantle cell lymphoma.

Options for relapsed/refractory indolent lymphoma include chemotherapy, immunotherapy and high-dose therapy with autologous support. The best combination of these approaches, however, is not defined. We treated 10 patients with relapsed/refractory follicular (n = 7) or mantle cell lymphoma (n = 3) using chemotherapy, immunotherapy, high-dose therapy and autotransplant in a sequence of four phases, each designed to play a specific role in tumour eradication. After the debulking with VACOP-B (doxorubicin, cyclophosphamide, etoposide, vincristine, prednisone, bleomycin) (phase 1), 9/10 patients responded but none achieved a molecular response. After the immuno-chemotherapy phase, which combined Rituximab with vincristine and cyclophosphamide, seven patients were in complete response (CR) and three in good partial response (PR), and all those with a molecular marker of disease showed a disappearance of the signal from marrow and blood. Phase 3, which coupled high-dose cytarabine with Rituximab, was effective in mobilizing an adequate number of progenitor cells that were polymerase chain reaction negative in all informative cases. Phase 4 consisted of high-dose therapy with autologous support followed by two doses of Rituximab. Autograft was performed in nine patients. The haematopoietic recovery was as expected. This sequence of chemotherapy, immuno-chemotherapy, stem cell mobilization with in vivo purging and autotransplant, organized in four blocks of treatment, was simple to administer and devoid of toxic effects. It permits rapid attainment of clinical and molecular response and enables the harvest of lymphoma-free peripheral blood progenitor cells even in heavily pretreated patients with relapsed or refractory disease.

Adult↗
PubMed2001

Antiretrovirals: simultaneous determination of five protease inhibitors and three nonnucleoside transcriptase inhibitors in human plasma by a rapid high-performance liquid chromatography--mass spectrometry assay.

An analytical technique using liquid chromatography (LC) coupled with electrospray-mass spectrometry (ESI--MS) has been developed for the simultaneous determination of five protease inhibitors (PIs): saquinavir, indinavir, ritonavir, nelfinavir, and amprenavir; and three non-nucleoside reverse transcriptase inhibitors (NNRTIs): nevirapine, delavirdine, and efavirenz, in human plasma. This assay allows the elution and identification of these drugs in a single run (10 minutes) using a linear gradient with water and acetonitrile. The procedure involves liquid--liquid extraction. High-performance liquid chromatography (HPLC) separation was achieved on a C18 reversed-phase column, with a linear gradient elution followed by mass spectrometry detection. The calibration curves, obtained by automatic process peak area integration, show a good linearity in a range of concentrations between 20 and 10,000 ng/mL (40--10,000 ng/mL for efavirenz). The limit of detection was approximately 10 ng/mL for seven drugs (25 ng/mL for efavirenz). The coefficients of variation (CV) were always less than 15% for both intraday and interday precision for each compound. The recovery of the eight drugs ranged from 88.5% to 100%. This novel LC/ESI--MS assay provides an excellent method for simultaneous quantitative monitoring of different components of the highly active antiretroviral treatments (HAARTs) in patients treated simultaneously with PIs and NNRTIs, and it has been successfully applied to therapeutic drug monitoring and pharmacokinetic studies.

Alkynes↗
PubMed2001

Pharmacokinetic evaluation of oral levofloxacin in human immunodeficiency virus-infected subjects receiving concomitant antiretroviral therapy.

The purpose of this study was to evaluate the pharmacokinetics (PK) profile of oral levofloxacin in human immunodeficiency virus-positive patients in steady-state treatment with nelfinavir (NFV) or with efavirenz (EFV) and to determine the effects of levofloxacin on the PK parameters of these two antiretroviral agents. For levofloxacin, plasma samples were obtained at steady state during a 24-h dosing interval. Plasma NFV and EFV concentrations were evaluated before and after 4 days of levofloxacin treatment. Levofloxacin PK do not seem affected by NFV and EFV. There was no significant difference between NFV and EFV plasma levels obtained with and without levofloxacin.

Administration, Oral↗
PubMed2001

Nelfinavir suspension obtained from nelfinavir tablets has equivalent pharmacokinetic profile.

The pharmacokinetics of nelfinavir tablets (A) and an oral simplified nelfinavir suspension (B) were studied. Twelve healthy volunteers randomly received either five 250-mg nelfinavir tablets or a simplified oral suspension obtained from tablets dissolved in water (nelfinavir 1250 mg in 100 mL of water) in a single dose before being crossed over to the second treatment after a one-week washout period. Blood samples were drawn up to 24 h after drug administration. Nelfinavir concentrations in plasma were analyzed by a specific and validated reverse-phase high-performance liquid chromatography assay (HPLC) with UV detection, and pharmacokinetic values were determined. For the AUC(0-infinity) with means+/-SD of 31.71+/-7.85, 30.88+/-10.28 (microg/L) respectively for treatments B and A, the ratio (F(B/A)) was of 1.1 with a C.I. of 0.90-1.24. For Cmax with means+/-SD of 3.1+/-0.6 (treatment B) and 3.2+/-0.8 mg/mL (treatment A), the ratio was 1.0. with C.I. of 0.92-1.08. The two treatments evidenced no significant differences in AUC(0-inifnity) and Cmax values and the two-one sided t-test showed that the two preparations are bioequivalent. There was no significant difference in Tmax between the liquid and tablets. Nelfinavir suspension might be a option for treating HIV-infected patients with swallowing disturbances or compliance problems.

Administration, Oral↗
PubMed2001

Comparison of the plasma pharmacokinetics of lamivudine during twice and once daily administration in patients with HIV.

OBJECTIVE: To compare the plasma pharmacokinetics of lamivudine 150mg twice daily and 300mg once daily in patients with HIV-1 infection. DESIGN: Nonblind, sequential, pharmacokinetic study. PARTICIPANTS: 13 patients with HIV-1 infection (median age 36 years). METHODS: Patients were tested during twice daily and then once daily regimens of lamivudine. In both regimens, the total daily dose of lamivudine was identical (300 mg/day). Blood samples for pharmacokinetic analysis were taken over a 12-hour period after > or =7 days of twice daily administration, and again over a 24-hour period after 7 days of once daily administration,. RESULTS: 12 patients completed the study. Lamivudine pharmacokinetic parameters (mean +/- SD) after administration of 150mg twice daily were: peak plasma concentration (Cmax) 2077+/-816 microg/L; trough plasma concentration (Cmin) 332+/-219 microg/L; elimination half-life (t 1/2beta) 6.1+/-1.9h; time to Cmax (t(max)) 1.6+/-0.7h; average concentration over the dosage interval (Cav) 711+/-269 microg/L; and area under the concentration-time curve (AUC) over 2 dosage intervals (24h) 17085+/-6464 microg x h/L. Corresponding values after administration of 300mg once daily were: Cmax 3461+/-854 microg/L; Cmin 146+/-87 microg/L; t1/2 7.9+/-3.4h; t(max) 2.2+/-1.3h; Cav 705+/-177 microg/L; and AUC over 1 dosage interval (24h) 16644+/-4150 microg x h/L. Statistical analysis showed a significant difference (p < 0.05) between the 2 schedules for Cmax and Cmin values, whereas no significant differences emerged for the other parameters. CONCLUSIONS: Once daily lamivudine leads to a similar exposure in plasma as twice daily administration of the same total daily dose. Since once daily administration may result in improved compliance, these results provide the pharmacokinetic basis for using lamivudine in a once daily regimen. Randomised clinical studies are needed to confirm this pharmacokinetic finding.

Adult↗
PubMed2000

Clinical pharmacokinetics of nelfinavir combined with efavirenz and stavudine during rescue treatment of heavily pretreated HIV-infected patients.

Nelfinavir is a novel protease inhibitor that exhibits good inhibitory activity against human immunodeficiency virus type 1 (HIV-1) and is currently used in combination with reverse transcriptase inhibitors for the management of HIV infection. In this study we analysed the pharmacokinetic profile of nelfinavir after multiple oral doses in 18 HIV-infected patients during a combination regimen of nelfinavir plus efavirenz and stavudine. Patients who received the study drug for >/=4 weeks were considered for pharmacokinetic evaluation. Blood samples were obtained at the following times: 0 (before nelfinavir administration), 1, 2, 3, 4, 6 and 8 h after administration. Nelfinavir plasma concentrations were analysed by a specific and validated HPLC assay with ultraviolet detection. Nelfinavir concentration-time data were analysed by compartmental and non-compartmental techniques and the pharmacokinetic parameters of nelfinavir were determined according to a one-compartment model. We found a high variability between individuals in nelfinavir plasma concentrations. The mean average drug plasma concentration was 2.22 +/- 1.25 mg/L and the mean AUC during the dosing interval was 17.7 +/- 10.0 mg*h/L. The mean nelfinavir trough plasma concentration was 1.58 +/- 1.0 mg/L. A good relationship was found between AUC(0-8h) and the plasma concentrations measured at 6 h, and the trough plasma concentrations made total body exposure for nelfinavir less predictable. Alternatively, a 2 h abbreviated AUC provides a good estimate of the full AUC(0-8h). Comparing the pharmacokinetic parameters obtained in our patients with those reported for patients receiving nelfinavir monotherapy or nelfinavir combined with nucleoside analogues, one observes substantial overlap with nelfinavir concentrations achieved without efavirenz.

Adult↗
PubMed2000

Rituximab (IDEC-C2B8): validation of a sensitive enzyme-linked immunoassay applied to a clinical pharmacokinetic study.

Rituximab is a chimeric monoclonal antibody (MAb) directed against the B-cell CD20 antigen that has been approved for therapy of relapsed and resistant follicular non-Hodgkin's lymphoma (NHL). This study describes the development and validation of a highly sensitive, rapid, accurate, precise enzyme-linked immunosorbent assay (ELISA) to measure Rituximab serum concentrations. This study also describes the application of the ELISA method to a pharmacokinetic study in a homogeneous group of patients with follicular lymphoma who received 4 weekly doses of MAb at the standard dose of 375 mg/m2 as consolidation of chemotherapy. In the patients in this study, the median Rituximab serum concentrations increased during therapy, and showed a slow decline during the posttreatment period. The Rituximab elimination half-life of approximately 20 days accounts for the demonstrated accumulation of MAb in serum samples. Because previous pharmacokinetic studies showed a correlation between Rituximab serum levels and tumor response, the ELISA method used in this study, which allows a precise control of serum concentrations, could be useful for predicting the final response to the MAb and for selecting patients able to benefit from higher dosage or repeated drug administration.

Antibodies, Monoclonal↗
PubMed2000

Considerable lack of agreement between S-FPIA and EMIT cyclosporine assay in therapeutic drug monitoring, of heart transplant recipients.

The authors performed a comparative analysis of 60 whole blood samples containing cyclosporine (CsA) from heart transplant (HTx) recipients (n = 60) by the two "specific" monoclonal immunoassays, enzyme-multiplied immunoassay technique (EMIT) and fluorescence polarization immunoassay (S-FPIA), using the Altman-Bland approach based on graphical techniques and simple calculations. The CsA blood concentrations measured by S-FPIA [mean (SD): 268.1 (108.8) ng/mL] showed a statistically significant difference (P < 0.001) from the corresponding concentrations measured by EMIT [219.6 (118.7) ng/mL]. The CsA concentrations were 27% (median) higher when determined by monoclonal S-FPIA than by EMIT. The comparison between EMIT and S-FPIA showed a good correlation (S-FPIA conc. (ng/mL) = EMIT conc. (ng/mL) x 0.88 + 76.1, r = 0.96, P < 0.001). However, a high correlation does not mean that the two methods agree, and their use as interchangeable might be misleading. The authors summarized the degree of agreement by calculating the bias estimated by the mean difference (d) and the standard deviation of the difference (SD). For CsA concentration data, the mean difference (S-FPIA minus EMIT) is +49.9 ng/mL and SD is 31.2 ng/mL. Altman-Bland analysis indicates considerable lack of agreement between EMIT and S-FPIA, with discrepancies of more than 100 ng/mL. The present study's data clearly show that there is a considerable and clinically unacceptable lack of agreement between the S-FPIA and the EMIT techniques in HTx recipients for the whole range of concentrations evaluated (25-500 ng/mL), and this is caused by the variation in the overestimation of the CsA parent compound. Even though a similar CsA reference range was reported during maintenance therapy for both methods (150-250 ng/mL), which might encourage their interchangeability in the clinical setting, this approach should be avoided. Laboratory reports should always state both the concentration of CsA and the analytical method.

Adult↗
PubMed1999

Efavirenz, nelfinavir, and stavudine rescue combination therapy in HIV-1-positive patients heavily pretreated with nucleoside analogues and protease inhibitors.

Tolerability, activity, and pharmacokinetic parameters of a combination therapy with efavirenz (EFV), nelfinavir (NFV), and stavudine (d4T) were evaluated in this study. Forty-seven HIV-1-infected study subjects, naive to NFV and nonnucleoside reverse transcriptase inhibitors (NNRTIs), who had experienced virologic failure while being treated with combination antiretroviral therapies including protease inhibitors (PIs), were enrolled. At baseline, HIV-1 viral load in plasma was 4.8 log10, CD4+ count was 204 cells/microl (both mean values); patients had received a mean of 3.1 different treatments (range, 2-5 treatments). Study medications were generally well tolerated; 7 of 47 patients (14.8%) were dropped from the study because of related drug toxicity. At week 24, mean plasma viral load (pVL) was reduced by 1.9 log10, with mean CD4+ count increased to 324 cells/microl (+/-59% from baseline); pVL was below the limit of detection (500 copies/ml) in 46.1% of patients. An extended follow-up study was performed at 12 months. Results showed a reduction of 1.7 log10 in pVL from basal values that was consistent with values observed at months 3 and 6. A history of previous use of PIs represented a negative prognostic marker. Sequencing analysis, performed in a subset of patients, showed the presence of multiple point mutations associated with PI resistance. Pharmacokinetic analysis demonstrated a marked interindividual variability in NFV plasma concentrations, producing in 4 of 18 patients (22%) trough concentrations lower than minimum effective concentration. In pretreated patients, further studies are needed to characterize the pharmacokinetic factors that affect response to therapy and the association of these results with the 95% inhibitory concentration (IC95) determined by phenotyping.

Adult↗
PubMed1999

Pharmacokinetics of efavirenz (EFV) alone and in combination therapy with nelfinavir (NFV) in HIV-1 infected patients.

AIMS: To define the pharmacokinetic profile of efavirenz (EFV) in HIV-1 infected patients, when administered alone or with nelfinavir (NFV). METHODS: Eleven HIV-positive patients, in steady-state treatment with EFV and 11 patients in steady-state treatment with EFV+NFV, were evaluated. Blood samples for pharmacokinetic analysis were obtained during a dosage interval. Plasma concentrations of EFV were determined by h.p.l.c. RESULTS: No significant difference was found between the principal pharmacokinetic parameters of EFV when administered alone or in combination with NFV (mean AUC: 57.1-7727.3 vs 60.9+/-12.3 microg ml-1 h; mean CL/F: 0.18+/-0.072 vs 0.16+/-0.04 l h-1 kg-1; mean Cmax: 4.0+/-1.7 vs 4.3+/-1.2 microg ml-1, and mean tmax: 4.1+/-1.7 vs 3.5+/-0.5 h) Mean trough plasma concentrations (C0) of EFV were 1.64+/-0.93 microg ml-1, with and without NFV. A good correlation was found between C0 and AUC(0,24h) (r=0.96; P<0. 01). CONCLUSIONS: Despite the common metabolic pathway, there was no significant influence of NFV on the pharmacokinetics of EFV. EFV exhibits a relatively low interindividual variability and a dosing regimen of 600 mg day-1 assures plasma concentrations that are adequate for inhibition of viral replication.

Adult↗
PubMed1999

Pharmacokinetic variability and strategy for therapeutic drug monitoring of saquinavir (SQV) in HIV-1 infected individuals.

AIMS: To investigate the pharmacokinetic profile of the protease inhibitor saquinavir (SQV) after multiple doses in HIV-positive patients and to evaluate the possibility of predicting total body exposure of SQV from concentrations determined at single time points. METHODS: Twenty HIV-positive patients on steady-state treatment with SQV (Hard-Gel-Capsule, Invirase(R)) were enrolled in this study. Serial blood samples were obtained during a dosing interval. SQV plasma concentrations were determined by high performance liquid chromatography (h.p.l.c.) and pharmacokinetic parameters were determined by noncompartmental techniques. RESULTS: There was a marked interindividual variability in SQV pharmacokinetic parameters with a 11-fold variability in total systemic exposure to SQV, as expressed by AUC(0,8h) values (range: 268-3009 ng ml-1 h, CV: 69%). The oral clearance shows an interindividual CV of 75%. A strong correlation (r=0.94) was found between SQV plasma concentration at 3 h (C3 h ) and AUC(0,8h). CONCLUSIONS: This study shows that C3 h is a good predictor for total body exposure of SQV and might be useful to predict SQV disposition in HIV-positive patients on steady-state treatment.

Acquired Immunodeficiency Syndrome↗
PubMed1999

The effects of iloprost infusion on microcirculation is independent of nitric oxide metabolites and endothelin-1 in chronic peripheral ischaemia.

BACKGROUND: Endothelial vascular tone modulators are thought to be involved in aetiopathogenesis of systemic sclerosis (SS) and of peripheral artery occlusive disease (PAOD). Iloprost, a prostacyclin (PGI2) analogue, induces clinical benefit in patients suffering from peripheral ischaemia. This study was performed to investigate the effect of this drug on endothelial function in vivo to elucidate the role of vascular tone modulators. METHODS: Fourteen PAOD and 15 SS patients were treated for 24 and 10 days respectively. On the first day, before and after therapy, nitric oxide metabolites (NO2-/NO3-) and endothelin-1 (ET-1) plasma concentrations were detected; moreover, the endothelium-dependent vasodilatation in response to artificial ischaemia was evaluated by means of an echo-Doppler device. RESULTS: The echo-Doppler evaluation showed that the percentage of arterial reactive dilatation was not modified by placebo or by iloprost, and that the increase in blood velocity flow lasted for a significant longer time after drug infusion (226.79 +/- 17.49 vs. 310.71 +/- 36.32 s; P > 0.04). NO2-/NO3- and ET-1 plasma concentration were higher in patients than in control subjects (P < 0.004). After 6 h of iloprost infusion, no significant modifications were detected. CONCLUSION: This study provides evidence that iloprost enhances the microvascular functional capacity and clinical benefit for patients. The effects of the drug seem to be independently or not directly correlated with its interactions with vascular tone modulators such as NO2-/NO3- or ET-1.

Adult↗
PubMed1999

Clinical pharmacokinetics of tacrolimus in heart transplant recipients.

We report pharmacokinetic data on tacrolimus in 14 heart transplant patients (2 women, 12 men). The median age and the median body weight were 55.5 years (range, 23-61 years) and 67.0 kg (55-79 kg), respectively. All patients were maintained on a triple-drug protocol (tacrolimus, azathioprine, and prednisone), with a 7-day antithymocyte globuline induction. The first tacrolimus dose, administered orally 1 to 5 days posttransplant, ranged from 0.03 to 0.4 mg/kg (median = 0.052 mg/kg). The maintenance dose ranged from 0.03 to 0.13 mg/kg/day (administered in two equal doses) to achieve blood levels of 5 of 20 ng/ml, as determined by a microparticle enzyme immunoassay (MEIA). Whole blood samples were drawn just before, at 0.5 hour, and at 1, 2, 3, 4, 6, 8, 10, and 12 hours after the administration of the first dose; trough levels were measured thereafter. The mean oral clearance (CL/F) and apparent volume of distribution (Vd/F) averaged 0.21+/-0.08 L/hour/kg and 2.4+/-0.8 L/kg while the half-life averaged 8.7+/-3.5 hours. Tacrolimus accumulation index during chronic therapy (Rac = Cmin(steady state)/Cmin(first dose) normalized to the same dose) averaged 1.3. Eighty-eight percent of the trough blood levels measured in our patients were within 5 and 20 ng/ml. The incidence of rejection in the study population was extremely low: a prevalence of grade 2 rejection or more, of 0.4+/-0.8 episodes/ patient was observed after a follow-up period of 8.8+/-2.2 months. Only one patient experienced severe renal toxicity, probably because of his preoperative precarious hemodynamic status. Pharmacokinetic data suggest that maintenance tacrolimus daily dose should be equal to 0.1 mg/kg/day to obtain trough blood concentrations of approximately 10 ng/ml. Inter- and intra-patient variability of tacrolimus blood concentration should be expected and justify careful monitoring.

Adult↗