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Biomedical subjects

Ian Judson

Publications and source records attributed to Ian Judson.

25 records · Page 2Linked to original sources
PubMed2003

The clinical applications of heat shock protein inhibitors in cancer - present and future.

The potential clinical applications of the prototype first-in-class Hsp90 inhibitor 17AAG and other emerging Hsp90 drugs are very exciting. Rigorously planned and executed clinical trials, incorporating measurement of appropriate biomarkers and pharmocodynamic endpoints are critical for selecting the optimal dose and schedule. A detailed understanding of the molecular mode of action of Hsp90 inhibitors alongside the elucidation of the molecular pathology of individual cancers will help us to identify tumour types and individual patients that will benefit most from treatment. Careful in vitro and in vivo experiments are needed to choose the most potentially advantageous combination studies. It is important to construct a pharmacologic audit trail linking molecular biomarkers and pharmacokinetic and pharmacodynamic parameters to tumour response endpoints. Phase I clinical studies with 17AAG have shown that the drug can be given at does that are well tolerated and that also achieve active pharmacokinetic exposures and elicit molecular signatures of gene and protein expression that are indicative of Hsp90 inhibition. Furthermore, examples of disease stabilisation have been documented, consistent with the generally cytostatic responses that are seen in animal models. Selecting tumour types for Phase II clinical trials must involve balancing 1) our knowledge of molecular response determinants, such as the expression of and dependence upon key client proteins and 2) more pragmatic evidence of antitumour activity in the relevant preclinical models. Examples of likely disease targets include chronic myeloid leukaemia, melanoma, breast, ovarian, brain, thyroid, colorectal and prostate cancer.

Animals↗
PubMed2003

A phase I trial of ZD9331, a water-soluble, nonpolyglutamatable, thymidylate synthase inhibitor.

PURPOSE: ZD9331 is a novel, direct-acting antifolate cytotoxic that does not require polyglutamation for activity, and is a specific thymidylate synthase inhibitor. This Phase I trial aimed to determine the maximum tolerated dose of ZD9331, given as a 30-min i.v. infusion on days 1 and 8 of a 21-day cycle. Pharmacokinetic parameters and tumor response were also assessed. EXPERIMENTAL DESIGN: A total of 71 patients, with a range of solid malignancies and refractory to standard therapies (44% had received > or =3 prior chemotherapy regimens), were treated. The most common malignancies were colorectal cancer (35% of patients) and ovarian cancer (31%). ZD9331 was escalated from 4.8 mg/m(2)/day. RESULTS: Dose-limiting toxicity occurred at 162.5 mg/m(2) ZD9331, with grade 4 thrombocytopenia, grade 4 neutropenia lasting > or =7 days, and grade 3 nonhematologic toxicity. Plasma clearance of ZD9331 was slow and dose-dependent; however, ZD9331 pharmacokinetics were nonlinear. Pharmacodynamics of ZD9331 were determined by measurement of plasma deoxyuridine, which increased at all of the dose levels; dose-related increases in plasma deoxyuridine were significant (P = 0.003) on day 5. Stable disease was observed in 37% of patients; 23% of ovarian cancer patients had a > or =50% reduction in CA125 levels. CONCLUSIONS: The maximum tolerated dose of this schedule was 130 mg/m(2). The toxicity profile at this dose was acceptable, with 7 of 28 patients treated developing grade 3/4 neutropenia and thrombocytopenia, 2 grade 4 diarrhea, and 2 grade 3/4 rash. This schedule was convenient and demonstrated activity in extensively pretreated patients; therefore, this is the recommended dose for study in Phase II trials.

Adult↗
PubMed2003

Phase I trial of ZD9331, a nonpolyglutamatable thymidylate synthase inhibitor, given as a 5-day continuous infusion to patients with refractory solid malignancies.

PURPOSE: This dose-escalating study investigated the toxicity, pharmacokinetics, and efficacy of the novel direct-acting antifolate ZD9331, given as a 5-day i.v. infusion every 3 weeks. EXPERIMENTAL DESIGN: Forty-five patients with refractory solid malignancies received ZD9331, which was escalated from 0.125 mg/m(2)/day. RESULTS: Dose-limiting grade 4 thrombocytopenia occurred in 3 of 6 patients treated at 8 mg/m(2)/day; other drug-related toxicities, across dose levels, included skin and gastrointestinal toxicity, lethargy, and asymptomatic, reversible, elevated transaminases. The maximum plasma concentration and area under the curve increased with dose. Clearance was dose-dependent and predominantly renal. At doses >/=2.4 mg/m(2)/day, plasma 2'-deoxyuridine levels were elevated consistently indicating inhibition of thymidylate synthase. Two patients had a partial response (breast, 1 patient; ovarian, 1 patient), and 10 patients had stable disease. CONCLUSION: The maximum tolerated dose was defined as 6 mg/m(2)/day, and the toxicity profile for this regimen was considered acceptable and manageable. Administration of ZD9331 lead to elevation of 2'-deoxyuridine levels, signifying thymidylate synthase inhibition, and evidence of antitumor activity was observed.

Adult↗
PubMed2003

The contemporary drug development process: advances and challenges in preclinical and clinical development.

We are in a new era of drug discovery, in which it is feasible to develop therapeutic agents targeted at a particular protein or biological activity in a living cell. This has been made possible by major advances in our understanding of cell and molecular biology, epitomized by the 2001 Nobel prize award for Physiology or Medicine to Lee Hartwell, Tim Hunt and Paul Nurse, who were recognised for their work on key regulators of the cell cycle. Technological advances have also played a decisive role, leading to the sequencing of the human genome and increased throughput at many stages of the drug discovery and development process. For example, developments in high throughput screening, structural biology and microarray technology are increasing the speed of drug discovery. In this chapter we focus on the long, and often difficult, pathway which leads from identification of a hit in a screen to regulatory approval of a drug for disease treatment. The emphasis in this chapter is on the development of anticancer drugs, as this is our own area of expertise and also because cancer is a disease in which the cell cycle is already a major target for therapeutic intervention. However, many of the concepts, approaches and issues are generally common to other therapeutic areas.

Animals↗
PubMed2002

A study to evaluate the pharmacokinetics of oral 5-fluorouracil and eniluracil after concurrent administration to patients with refractory solid tumours and varying degrees of renal impairment (FUMA1005).

BACKGROUND: Eniluracil is an inactivator of dihydropyrimidine dehydrogenase, the first enzyme in the catabolic pathway of 5-fluorouracil (5-FU). Concurrent administration of oral eniluracil with oral 5-FU not only increases the bioavailability of 5-FU, owing to elimination of first-pass metabolism, but can change the route of elimination of 5-FU from hepatic metabolism to renal excretion. An open-label study was performed to determine the effect of renal impairment on the pharmacokinetics of 5-FU in the presence of eniluracil. METHODS: Enrolled in the study were 17 patients with refractory solid tumours (Karnofsky performance status >/=70%; age 31-74 years; 12 male, 5 female). The patients were separated into two groups based upon creatinine clearance (CLCr): group A had "normal" renal function arbitrarily defined as CLCr >/=50 ml/min ( n=8), and group B had moderate renal impairment, i.e. CLCr <50 ml/min ( n=9). Treatment was separated into test and treatment periods. During the test period all patients received eniluracil 50 mg orally on days 1-3 and 5-FU 10 mg/m(2) together with pharmacokinetic measurements. During the treatment period, all patients received eniluracil 50 mg orally on days 1-7 with 5-FU at a standard dose of 20 mg/m(2) for those in group A or a dose individualized according to the pharmacokinetic parameters in the test period for those in group B. RESULTS: The clearance of both eniluracil and 5-FU was decreased in patients with renal impairment compared to those with normal renal function. A linear relationship was observed between 5-FU CL/F and CLCr in patients with renal impairment, but not in those with normal renal function. 5-FU dose modification, on the basis of the test dose pharmacokinetic data for the patients with renal function impairment, accurately resulted in drug exposure in the potentially therapeutic range. Toxicity was not increased. CONCLUSIONS: Eniluracil increases the oral bioavailability of 5-FU and results in a switch from hepatic metabolism to renal elimination. A standard dose of this combination can be administered safely to patients with CLCr >50 ml/min. The combination can also be given to patients with renal impairment using a test dose and pharmacokinetic measurements to predict the appropriate dose of 5-FU. It is expected that sufficient information will be available from this and other studies to allow accurate prediction of the appropriate 5-FU dose modifications required in patients with renal impairment.

Administration, Oral↗
PubMedDate not supplied

Progression-free survival in gastrointestinal stromal tumours with high-dose imatinib: randomised trial.

BACKGROUND: Imatinib is approved worldwide for use in gastrointestinal stromal tumours (GIST). We aimed to assess dose dependency of response and progression-free survival with imatinib for metastatic GIST. METHODS: 946 patients were randomly allocated imatinib 400 mg either once or twice a day. Those assigned the once a day regimen who had progression were offered the option of crossover. The primary endpoint was progression-free survival. Analysis was by intention to treat. FINDINGS: At median follow-up of 760 days (IQR 644-859), 263 (56%) of 473 patients allocated imatinib once a day had progressed compared with 235 (50%) of 473 who were assigned treatment twice a day (estimated hazard ratio 0.82 [95% CI 0.69-0.98]; p=0.026). Side-effects arose in 465/470 (99%) patients allocated the once daily regimen compared with 468/472 (99%) assigned treatment twice a day. By comparison with the group treated once a day, more dose reductions (77 [16%] vs 282 [60%]) and treatment interruptions (189 [40%] vs 302 [64%]) were recorded in patients allocated the twice daily regimen, but treatment in both arms was fairly well tolerated. 52 (5%) patients achieved a complete response, 442 (47%) a partial response, and 300 (32%) stable disease, with no difference between groups. Median time to best response was 107 days (IQR 58-172). INTERPRETATION: If response induction is the only aim of treatment, a daily dose of 400 mg of imatinib is sufficient; however, a dose of 400 mg twice a day achieves significantly longer progression-free survival.

Aged↗