Aims To assess the tolerability and pharmacokinetic profile of single and repeat doses of the oral matrix metalloproteinase inhibitor marimastat in healthy male volunteers. Methods A total of 31 subjects participated in two placebo-controlled, rising-dose studies. The first study assessed the pharmacokinetics and tolerability of single doses of marimastat of 25, 50, 100, 200, 400 and 800 mg. In the second study, continuous dosing over 6.5 days with three incremental dose levels of 50, 100 and 200 mg twice daily was assessed. Full pharmacokinetic profiles were obtained on days 0 and 6, and trough concentrations were measured on all days. For each pharmacokinetic profile in the studies, summary measures including C max , t max , elimination half-life and AUC were calculated. Urinary drug weights were also measured. All adverse events were documented, and haematological and biochemical variables, vital signs and ECGs were monitored throughout the study. Results Peak plasma concentrations were observed at 1.5-3 h for all subjects at all doses. Peak levels were approximately proportional to dose, as was drug exposure as calculated by AUC. Data from both studies indicate that the terminal elimination half-life is of the order of 8-10 h, and that there is no unexpected drug accumulation. Marimastat was well-tolerated, with adverse effects being mild and occurring with similar frequency to placebo. Small but reversible elevations in liver transaminases were noted with repeat dosing of marimastat, the most significant of these occurring at a dose of 200 mg twice daily. Conclusion Single and repeat oral doses of marimastat in healthy male subjects appear to be well-tolerated. The drug is rapidly absorbed with high peak levels achieved. It has a terminal elimination half-life of 8-10 h which would support twice daily dosing in further clinical trials.

The failure of many cytostatic agents in Phase III clinical trials for treatment of common cancers has led researchers to question current approaches to trial development. Recent studies offer some clues as to what is wrong with two particular aspects of clinical trial design--survival as an end point and simultaneous combination with cytotoxic chemotherapy--and indicate possible alternatives.

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Marimastat is a specific inhibitor of matrix metalloproteinases that has been shown to be effective in cancer models. A pilot, escalating-dose study of oral marimastat was performed in patients with recurrent colorectal cancer, in whom evaluation of serological response was made by measurement of carcinoembryonic antigen (CEA) levels. The study assessed the safety and tolerability of 4 weeks administration of marimastat, and determined a dose range producing detectable serological effects. Patients were recruited with a serum CEA level greater than 5 ng ml −1 , and rising by more than 25% over a 4-week screening period. Patients were treated for 28 days and entered into a continuation protocol if a serological response or clinical benefit was observed. Pharmacokinetic and safety data determined that groups of patients were recruited sequentially at 25 mg and 50 mg twice daily, and, thereafter, 10 mg twice daily, 10 mg once daily, 5 mg once daily and 20 mg once daily. A biological effect (BE) was defined as a CEA value on day 28 no greater than on day 0; a partial biological effect (PBE) was defined as a rise in CEA over the 28-day treatment period of less than 25%. Of 70 patients recruited, 63 completed the 28-day treatment period, and 55 were eligible for cancer antigen analysis. Examination of the dose–effect relationships provides evidence for a causal relationship between marimastat and biological effects: the proportion of patients with BE or PBE was higher with twice daily dosing (16 out of 25, 64%) than with once daily dosing (11 out of 30, 37%) ( P = 0.043, χ 2 test). Furthermore, the median rates of rise of CEA fell markedly during treatment compared with the screening period for patients receiving twice daily marimastat ( P < 0.0001), but not for patients receiving marimastat once daily ( P = 0.25). Musculoskeletal adverse events emerged as the principal drug-related toxicity of marimastat, occurring in a dose- and time-dependent fashion. It was concluded that marimastat was associated with dose-dependent biological effects in cancer patients. The occurrence of musculoskeletal side-effects define 25 mg twice daily as the upper limit of the dose range for continuous use in further studies. Therefore, a dose range of 20 mg once daily to 25 mg twice daily seems appropriate for further studies, which should aim to demonstrate the efficacy of the drug in terms of conventional clinical end points and describe the long-term tolerability of this novel agent. © 1999 Cancer Research Campaign

A 41-year-old man developed severe hepatic dysfunction following a 3.5-week course of terbinafine (250 mg/day). He suffered marked pruritus, jaundice, malaise, anorexia and loin pain. Serum bilirubin rose to a peak value of 718 micromol/l with alkaline phosphatase at 569 U/l, alanine aminotransferase at 90 U/l, aspartate aminotransferase at 63 U/l and a prolonged prothrombin time of 21 s, unresponsive to vitamin K. Transjugular liver biopsy showed canalicular cholestasis consistent with a drug reaction. Symptoms resolved 11 months after drug cessation, with liver function tests returning to normal values after 15 months. This case represents the most severe cholestatic reaction reported to date, resulting in patient recovery without liver transplantation. A comprehensive literature review is provided.