Raltitrexed (Tomudex) is a specific inhibitor of thymidylate synthase and has recently been licensed in Europe for use in the treatment of advanced colorectal carcinoma. This study evaluated the metabolism, excretion and pharmacokinetics after a single dose of 3.0 mg/m2 [14C]-raltitrexed in patients with advanced solid malignancies not amenable to curative therapy. From April 1994 to July 1995, nine patients (six men and three women) were recruited into the study. Pharmacokinetics analysis was performed during the first cycle of treatment in all patients and, in two patients, limited sampling was done prior to and during the second cycle of treatment. The mean observed peak plasma concentration (Cmax) was 700.6 ng/ml and the median time (tmax) to reach maximal raltitrexed concentrations was 15 min after the initiation of the infusion. After reaching Cmax the drug declined in a triexponential manner with a terminal half-life of 257 h. The AUC0-infinity as predicted by the pharmacokinetic model was 2341.7 ng h ml(-1). Clearance was 41.3 ml/min, of which renal clearance accounted for 50-60%. Urinary collection for the measurement of radiolabeled drug revealed that renal excretion extrapolated to infinity accounted for 40% of the total radioactive dose. Faecal excretion accounted for only 3% of the dose when samples were collected to day 5 in the first six patients. Collection was extended to 10 days in the last three patients and faecal elimination accounted for 14% in these patients. Raltitrexed measurements prior to subsequent doses suggest that there was no accumulation of the drug with repeated administration. Low levels of radioactivity measured in the red cell pellets on days 15, 22 and 29 are likely to represent drug retained by newly forming red cells at the time of dosing. Examination of the urine revealed that the drug was excreted unchanged. The toxicities seen were in line with those encountered in previous studies. Grade 3 and 4 thrombocytopenia occurred in three patients and grade 3 neutropenia occurred in two patients.
Background Globally rifampicin-resistant tuberculosis disease affects around 460,000 people each year. Currently recommended regimens are 9–24 months duration, have poor efficacy and carry significant toxicity. A shorter, less toxic and more efficacious regimen would improve outcomes for people with rifampicin-resistant tuberculosis. Methods TB-PRACTECAL is an open-label, randomised, controlled, phase II/III non-inferiority trial evaluating the safety and efficacy of 24-week regimens containing bedaquiline and pretomanid to treat rifampicin-resistant tuberculosis. Conducted in Uzbekistan, South Africa and Belarus, patients aged 15 and above with rifampicin-resistant pulmonary tuberculosis and requiring a new course of therapy were eligible for inclusion irrespective of HIV status. In the first stage, equivalent to a phase IIB trial, patients were randomly assigned one of four regimens, stratified by site. Investigational regimens include oral bedaquiline, pretomanid and linezolid. Additionally, two of the regimens also included moxifloxacin (arm 1) and clofazimine (arm 2) respectively. Treatment was administered under direct observation for 24 weeks in investigational arms and 36 to 96 weeks in the standard of care arm. The second stage of the study was equivalent to a phase III trial, investigating the safety and efficacy of the most promising regimen/s. The primary outcome was the percentage of unfavourable outcomes at 72 weeks post-randomisation. This was a composite of early treatment discontinuation, treatment failure, recurrence, lost-to-follow-up and death. The study is being conducted in accordance with ICH-GCP and full ethical approval was obtained from Médecins sans Frontières ethical review board, London School of Hygiene and Tropical Medicine ethical review board as well as ERBs and regulatory authorities at each site. Discussion TB-PRACTECAL is an ambitious trial using adaptive design to accelerate regimen assessment and bring novel treatments that are effective and safe to patients quicker. The trial took a patient-centred approach, adapting to best practice guidelines throughout recruitment. The implementation faced significant challenges from the COVID-19 pandemic. The trial was terminated early for efficacy on the advice of the DSMB and will report on data collected up to the end of recruitment and, additionally, the planned final analysis at 72 weeks after the end of recruitment. Trial registration Clinicaltrials.gov NCT02589782. Registered on 28 October 2015.
Summary This open-label, non-randomized, parallel-group trial investigated the pharmacokinetics of raltitrexed (Tomudex, formerly ZD1 694) after a single intravenous dose of 3.0 mg m-2, comparing eight cancer patients with mild to moderate renal impairment (creatinine clearance 25-65 ml min-') with eight cancer patients with normal renal function (creatinine clearance >65 ml min-'). The primary end points were area under the plasma raltitrexed concentration-vime curve from the start of the infusion to the last determined concentration (AUCo_) and AUC to infinity (AUCo); secondary end points were peak corncentrations of ralftitrexed (C,n,,) and elimination half-life (t,>). The groups were compared statistically using analysis of covariance. The AUCs were greater for patients with renal impairment than for patients with normal renal function (2452.2 compared with 1247.3 ng h ml-' for AUCo._. (ratio 1.97; 95% Cl 1.36-2.84); 2961.5 compared with 1457.0 ng h ml-' for AUCo_ (ratio 2.03; 1.25-3.29). These differences were statistically significant (P = 0.002 and P = 0.008 for AUC,, and AUCo_ respectively. 50-lOO h (Clarke et al. 1996). This prolonged t1,, may represent hydrolysis of the polvalutamated
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