Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0015672 (fatigue)
 51,768 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Farnesyl transferase (FT) inhibitors block the main post-translational modification of the Ras protein, thus interfering with its localisation to the inner surface of the plasma membrane and subsequent activation of downstream effectors. Although initially developed as a strategy to target Ras in cancer, FT inhibitors have subsequently been acknowledged as acting by additional and more complex mechanisms that may extend beyond Ras, involving RhoB, centromere-binding proteins and probably other farnesylated proteins. SCH66336 (lonafarnib, Sarasar( trade mark ); Schering-Plough), a tricyclic orally active FT inhibitor, was the first of these compounds to undergo clinical development. Gastrointestinal tract toxicities and fatigue have qualified as dose-limiting toxicities in all Phase I/II studies. Evidence of clinical activity has been reported. Lonafarnib combination studies with both gemcitabine and paclitaxel have been carried out. No unexpected toxicities were observed in these Phase I studies, while encouraging clinical activity was observed mainly in pancreatic cancer and non-small cell lung cancer. Further combination studies are ongoing. R115777 (Zarnestra( trade mark ); Janssen Pharmaceutica) is another orally active FT competitive inhibitor in clinical development. Single-agent Phase I/II studies have shown that myelotoxicity and neurotoxicity are dose-limiting toxicities; intermittent schedule is probably better tolerated; antitumour activity is observed particularly in breast cancer and haematological malignancies. A number of combination studies with R115777 have been carried out. A recently completed, large Phase III trial comparing gemcitabine plus R115777 versus gemcitabine plus placebo in advanced pancreatic cancer has failed to demonstrate any survival benefit in the R115777 arm. BMS-214662 is the third FT inhibitor in clinical development. It has the main advantage of being cytotoxic in nature, rather than cytostatic, and potent in vivo antitumour activity has been reported. A major drawback for BMS-214662 is its severe gastrointestinal and liver toxicities, which prevent the achievement of adequate systemic exposures following the oral route. Alternative ways of interference with the ras oncogene pathway, in particular inhibition of ras downstream effectors, are discussed and early clinical data are presented.
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PMID:Farnesyl transferase inhibitors in clinical development. 1278 99

The farnesyltransferase inhibitors (FTIs) are in active clinical development in a variety of human malignancies. The most promising activity to date has been demonstrated in patients with hematological malignancies, in particular acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). In patients with MDS, two non-peptidomimetic agents, tipifarnib (Zarnestra, Johnson & Johnson, New Brunswick, NJ) and lonafarnib (Sarasar, Schering-Plough, Kenilworth, NJ) have been the most extensively studied. In both phase I and phase II trials, tipifarnib has demonstrated significant efficacy with overall response rates of 30%, with complete remissions in about 15%. Dose-limiting side effects have been primarily myelosuppression, although fatigue, neurotoxicity, and occasional renal dysfunction have required dose reductions. Lonafarnib in patients with MDS has also resulted in clinical responses in approximately 30%, including significant improvements in platelet counts. Lonafarnib has been associated with primarily diarrhea and other gastrointestinal toxicity, anorexia, and nausea, which has limited its efficacy. Clinical response correlation with documentation of inhibition of farnesyltransferase and/or evidence of decreased farnesylation of downstream protein targets has not been demonstrated with either agent. In addition, the presence of an activating Ras mutation has not predicted response to therapy with FTIs in MDS and AML. Despite this, significant clinical efficacy of the FTIs in MDS, on par with that of currently available chemotherapeutic agents, has been observed, leading to further development of this new class of drugs in MDS and AML.
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PMID:Farnesyltransferase inhibitors in myelodysplastic syndrome. 1586 70

Although an activating mutation of Ras is commonly observed in myelodysplastic syndrome (MDS), the role of Ras in the natural history of MDS remains largely unknown. We prospectively studied efficiency and tolerance of lonafarnib, a compound able to inhibit Ras signalling pathway through an inhibition of farnesyl transferase, in patients with MDS or secondary acute myeloid leukaemia (sAML). Lonafarnib was administered orally at a dose of 200 mg twice daily for three courses of 4 weeks (separated by 1 to 4 weeks without treatment). Sixteen patients were included: FAB/RAEB (n = 10), RAEB-T (n = 2), sAML (n = 2) and chronic myelomonocytic leukaemia (CMML; n = 2); WHO/RAEB-1 (n = 4), RAEB-2 (n = 5), AML (n = 5), CMML (n = 2). Median age was 70 (53-77) years. The karyotype was complex or intermediate in 11 patients, and the International Prognostic Scoring Systems (IPSS) risk groups were low in two patients, INT-1 in one patient, INT-2 in four patients and high in six patients (unknown or not applicable in three patients). Among the 14 patients tested, five had Ras mutations in codons 12, 13 or 61 of N-Ras, K-Ras or H-Ras. One patient was excluded of the analysis for protocol violation, and 15 patients were assessable for tolerance. Gastrointestinal toxicities (diarrhoea, nausea and anorexia) and myelosuppression were the major side effects. Other toxicities included infections, fatigue, increase of liver enzymes, arrhythmia and skin rash. One patient died of infection, and the treatment was stopped in one other who developed atrial fibrillation. Doses were reduced in all but one patient treated with more than one course of farnesyl transferase inhibitor. Responses were assessable in 12 patients. A partial response in one sAML patient and a very transient decrease of blast cell count with normalisation of karyotype in one MDS patient were observed. No relation between improvement of marrow parameters and detected Ras mutations was observed. Lonafarnib alone, administered following our schedule, has shown limited activity in patients with MDS or secondary AML. Gastrointestinal and haematological toxicities appear the limiting toxicity in this population of patients.
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PMID:Farnesyl transferase inhibitor (lonafarnib) in patients with myelodysplastic syndrome or secondary acute myeloid leukaemia: a phase II study. 1864 85

The farnesyltransferase inhibitors (FTIs) are in active clinical development in a variety of human malignancies. The most promising activity to date has been demonstrated in patients with hematologic malignancies, in particular acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). In patients with MDS, two nonpeptidomimetic agents, tipifarnib (Zarnestra, Johnson & Johnson, New Brunswick, NJ) and lonafarnib (Sarasar, Schering-Plough, Kenilworth, NJ) have been the most extensively studied. In both phase I and phase II trials, tipifarnib has demonstrated significant efficacy, with overall response rates of 30% and complete remissions in about 15%. Dose-limiting adverse effects have been primarily myelosuppression, although fatigue, neurotoxicity, and occasional renal dysfunction have required dose reductions. Lonafarnib in patients with MDS has also resulted in clinical responses in approximately 30%, including significant improvements in platelet counts. Lonafarnib has been associated primarily with diarrhea and other gastrointestinal toxicity, anorexia, and nausea, which has limited its efficacy. Clinical response correlation with documentation of inhibition of farnesyltransferase and/or evidence of decreased farnesylation of downstream protein targets has not been demonstrated with either agent. In addition, the presence of an activating Ras mutation has not predicted response to therapy with FTIs in MDS and AML. Despite this lack of evidence, significant clinical efficacy of the FTIs has been observed in MDS, on a par with the efficacy of currently available chemotherapeutic agents, leading to further development of this new class of drugs in MDS and AML.
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PMID:Farnesyltransferase inhibitors in myelodysplastic syndrome. 2042 27