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

Farnesyl protein transferase inhibitors (FTIs) represent a new class of anticancer agents specifically targeting aberrant biologic processes involved with cellular transformation and malignancy. Originally developed to inhibit tumors by preventing activation of oncogenic ras genes via suppression of their posttranslational farnesylation, their anticancer activity appears to stem from their ability to inhibit farnesylation of various proteins that mediate signal transduction, growth, apoptosis, and angiogenesis. The safety, biologic activity, clinical response, and pharmacokinetics of R115777, a potent, orally active FTI, were recently investigated in a phase I dose-ranging study in patients with acute leukemias. Patients with acute myelogenous leukemia (AML), acute lymphocytic leukemia (ALL), or chronic myelogenous leukemia (CML) in blast crisis received R115777 100 mg, 300 mg, 600 mg, 900 mg, or 1,200 mg twice daily for 21 days. Cycles were repeated every 28 to 31 days for up to four cycles. An overall response rate of 29% (10/34 evaluable patients) was observed across all R115777 doses. R115777 was well tolerated; common adverse events included fatigue, increased creatinine, nausea, and neutropenia. Dose-limiting toxicity occurred at 1,200 mg twice daily. Farnesylation of lamin A and HDJ-2, examined as biologic end points, was inhibited by R115777 doses > or = 600 mg twice daily. Pharmacokinetic evaluation suggests that R115777 is concentrated in bone marrow at steady state. The biologic and antitumor activity and favorable tolerability of R115777 support further clinical evaluation alone and in combination therapy in hematologic malignancies.
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PMID:Farnesyl protein transferase inhibitors as targeted therapies for hematologic malignancies. 1152 24

R115777 is a potent farnesyltransferase (FTase) inhibitor with substantial antitumor activity in preclinical models. We conducted a phase 1 study (3 + 3 design) of R115777 in patients with myelodysplastic syndrome (MDS). R115777 was administered twice daily (3-weeks-on/1-week-off schedule for 8 weeks) (starting dosage, 300 mg by mouth twice daily; total, 600 mg). Maintenance therapy at the dose/schedule tolerated during induction could be continued until toxicity or lack of benefit. Twenty-one patients with MDS were treated (median age, 66 years). Four (19%) patients had ras mutations (n-ras,3; k-ras, 1). Objective responses (hematologic improvement, 3; partial remission, 2; or complete remission, 1) were seen in 6 of 20 (30%) evaluable patients, only 2 of whom had ras mutations. Response sequences were unusual in some patients who had increases in platelet counts without intervening aplasia. Other responders demonstrated an initial, albeit modest, myelosuppressive effect. The maximum tolerated dose was 400 mg by mouth twice a day. The most frequent side effect was myelosuppression. Dose-limiting toxicities (fatigue and confusion) occurred at 900 mg by mouth total daily dose. R115777 inhibited HDJ-2 prenylation and suppressed the activity of FTase, but not of the related geranylgeranyltransferase I enzyme, in peripheral blood mononuclear cells. Modulation of Akt, Erk, and signal transducer and activator of transcription 3 (STAT3) phosphorylation was variable, and responses occurred even without their down-regulation. Reductions in serum tumor necrosis factor-alpha (TNF-alpha) levels by day 7 showed a trend toward correlation with response (P =.09). We conclude that, at doses that are well tolerated, R115777 markedly inhibits the FTase target and has antitumor activity in MDS.
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PMID:Farnesyltransferase inhibitor R115777 in myelodysplastic syndrome: clinical and biologic activities in the phase 1 setting. 1294 10

Patients with multiple myeloma (MM) with mutated RAS are less likely to respond to chemotherapy and have a shortened survival. Therefore, targeting RAS farnesylation may be a novel approach to treatment of MM. We evaluated the activity and tolerability of the farnesyltransferase (FTase) inhibitor tipifarnib (Zarnestra) in a phase 2 trial as well as its ability to inhibit protein farnesylation and oncogenic pathways in patients with relapsed MM. Forty-three patients (median age, 62 years [range, 33-82 years]) with a median of 4 (range, 1-6) chemotherapy regimens entered the study. Tipifarnib, 300 mg orally twice daily, was administered for 3 weeks every 4 weeks. The most common toxicity was fatigue occurring in 66% of patients. Other toxicities included diarrhea, nausea, neuropathy, anemia, and thrombocytopenia. Sixty-four percent of the patients had disease stabilization. Treatment with tipifarnib suppressed FTase (but not geranylgeranyltransferase I) in bone marrow and peripheral blood mononuclear cells and also inhibited the farnesylation of HDJ-2 in unfractionated mononuclear cells and purified myeloma cells. Inhibition of farnesylation did not correlate with disease stabilization. Finally, tipifarnib decreased the levels of phosphorylated Akt and STAT3 (signal transducer and activator of transcription 3) but not Erk1/2 (extracellular signal regulated kinase 1 and 2) in bone marrow cells. We conclude that tipifarnib is tolerable, can induce disease stabilization, and can inhibit farnesylation and oncogenic/tumor survival pathways.
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PMID:Farnesyltransferase inhibitor tipifarnib is well tolerated, induces stabilization of disease, and inhibits farnesylation and oncogenic/tumor survival pathways in patients with advanced multiple myeloma. 1472 2