Hidalgo, Manuel

Abstract Purpose: To determine the maximum tolerated dose (MTD), characterize the principal toxicities, and assess the pharmacokinetics of EKB-569, an oral selective irreversible inhibitor of the epidermal growth factor receptor tyrosine kinase, in combination with capecitabine in patients with advanced colorectal cancer. Experimental Design: Patients were treated with EKB-569 daily for 21 days and capecitabine twice daily for 14 days of a 21-day cycle. The dose levels of EKB-569 (mg/day) and capecitabine (mg/m2 twice daily) assessed were 25/750, 50/750, 50/1,000 and 75/1,000. An expanded cohort was enrolled at the MTD to better study toxicity and efficacy. Samples of plasma were collected to characterize the pharmacokinetics of the agents. Treatment efficacy was assessed every other cycle. Results: A total of 37 patients, the majority of whom had prior chemotherapy, received a total of 163 cycles of treatment. Twenty patients were treated at the MTD, 50 mg EKB-569, daily and 1,000 mg/m2 capecitabine twice daily. Dose-limiting toxicities were diarrhea and rash. No patients had complete or partial responses but 48% had stable disease. The conversion of capecitabine to 5-fluorouracil was higher for the combination of EKB-569 and capecitabine (321 ± 151 ng*h/mL) than for capecitabine alone (176 ± 62 ng*hours/mL; P = 0.0037). Conclusion: In advanced colorectal cancer, 50 mg EKB-569 daily can be safely combined with 1,000 mg/m2 capecitabine twice a day. A statistically significant increase in plasma levels of 5-fluorouracil for the combination of EKB-569 and capecitabine may be due to the single-dose versus multiple-dose exposure difference, variability in exposure or a potential drug interaction.

Abstract Purpose: Patients with advanced cancer received temsirolimus (Torisel, CCI-779), a novel inhibitor of mammalian target of rapamycin, i.v. once daily for 5 days every 2 weeks to determine the maximum tolerated dose, toxicity profile, pharmacokinetics, and preliminary antitumor efficacy. Experimental Design: Doses were escalated in successive cohorts of patients using a conventional phase I clinical trial design. Samples of whole blood and plasma were collected to determine the pharmacokinetics of temsirolimus and sirolimus, its principal metabolite. Results: Sixty-three patients were treated with temsirolimus (0.75-24 mg/m2/d). The most common drug-related toxicities were asthenia, mucositis, nausea, and cutaneous toxicity. The maximum tolerated dose was 15 mg/m2/d for patients with extensive prior treatment because, in the 19 mg/m2/d cohort, two patients had dose-limiting toxicities (one with grade 3 vomiting, diarrhea, and asthenia and one with elevated transaminases) and three patients required dose reductions. For minimally pretreated patients, in the 24 mg/m2/d cohort, one patient developed a dose-limiting toxicity of grade 3 stomatitis and two patients required dose reductions, establishing 19 mg/m2/d as the maximum acceptable dose. Immunologic studies did not show any consistent trend toward immunosuppression. Temsirolimus exposure increased with dose in a less than proportional manner. Terminal half-life was 13 to 25 hours. Sirolimus-to-temsirolimus exposure ratios were 0.6 to 1.8. A patient with non–small cell lung cancer achieved a confirmed partial response, which lasted for 12.7 months. Three patients had unconfirmed partial responses; two patients had stable disease for ≥24 weeks. Conclusion: Temsirolimus was generally well tolerated on this intermittent schedule. Encouraging preliminary antitumor activity was observed.

Purpose The maximum tolerated dose (MTD) and the dose-limiting toxicities of EKB-569, a selective, irreversible inhibitor of the epidermal growth factor receptor (EGFR), when administered orally once daily on an intermittent-dose schedule (14 days of a 28-day cycle) or on a continuous-dose schedule (each day of a 28-day cycle), were determined in patients with advanced solid tumors. Patients and Methods Planned dose escalation was 25, 50, 75, 125, 175, and 225 mg. Pharmacokinetic sampling was performed on days 1 and 14 for the intermittent-dose cohort and on days 1 and 15 for the continuous-dose cohort. Results Thirty patients received a median of two cycles (range, one to 10 cycles) in the intermittent-dose cohort; 29 patients received a median of three cycles (range, one to eight cycles) in the continuous-dose cohort. Dose-limiting toxicity was grade 3 diarrhea, and the MTD was 75 mg EKB-569 per day for both cohorts. Other common toxicities included rash, nausea, and asthenia. Exposure to EKB-569 was dose proportional. At the MTD, the mean ± standard deviation terminal half-life was 21.7 ± 4.2 hours and peak concentration increased 1.2-fold from day 1 to day 14/15. No major antitumor responses were observed. However, one patient with non–small-cell lung cancer and one with cutaneous squamous cell carcinoma had stable disease for 33 and 24 weeks, respectively. Conclusion The MTD of once-daily oral EKB-569 is 75 mg. The tolerable toxicity profile and long half-life of this irreversible EGFR inhibitor warrant its further evaluation as a single agent and in combination with other drugs.

Background Temsirolimus (CCI-779) is a small-molecule inhibitor of the mammalian target of rapamycin (mTOR) and represents a rational therapeutic target against glioblastoma multiforme (GBM). Methods Recurrent GBM patients with ≤ 1 chemotherapy regimen for progressive disease were eligible. Temsirolimus was administered in a 250-mg intravenous dose weekly. Results Sixty-five patients were treated. The incidence of grade 3 or higher nonhematologic toxicity was 51%, and consisted mostly of hypercholesterolemia (11%), hypertriglyceridemia (8%), and hyperglycemia (8%). Grade 3 hematologic toxicity was observed in 11% of patients. Temsirolimus peak concentration (Cmax), and sirolimus Cmax and area under the concentration-time curve were decreased in patients receiving p450 enzyme–inducing anticonvulsants (EIACs) by 73%, 47%, and 50%, respectively, but were still within the therapeutic range of preclinical models. Twenty patients (36%) had evidence of improvement in neuroimaging, consisting of decrease in T2 signal abnormality +/− decrease in T1 gadolinium enhancement, on stable or reduced steroid doses. Progression-free survival at 6 months was 7.8% and median overall survival was 4.4 months. Median time to progression (TTP) for all patients was 2.3 months and was significantly longer for responders (5.4 months) versus nonresponders (1.9 months). Development of grade 2 or higher hyperlipidemia in the first two treatment cycles was associated with a higher percentage of radiographic response (71% v 31%; P = .04). Significant correlation was observed between radiographic improvement and high levels of phosphorylated p70s6 kinase in baseline tumor samples (P = .04). Conclusion Temsirolimus is well tolerated in recurrent GBM patients. Despite the effect of EIACs on temsirolimus metabolism, therapeutic levels were achieved. Radiographic improvement was observed in 36% of temsirolimus–treated patients, and was associated with significantly longer TTP. High levels of phosphorylated p70s6 kinase in baseline tumor samples appear to predict a patient population more likely to derive benefit from treatment. These findings should be validated in other studies of mTOR inhibitors.

Circulating cytokines, hormones, and growth factors control all aspects of cell proliferation, differentiation, angiogenesis, apoptosis, and senescence. These chemical signals are propagated from the cell surface to intracellular processes via sequential kinase signaling, arranged in modules that exhibit redundancy and cross talk. This signal transduction system comprising growth factors, transmembrane receptor proteins, and cytoplasmic secondary messengers is often exploited to optimize tumor growth and metastasis in malignancies. Thus, it represents an attractive target for cancer therapy. This review will summarize current knowledge of selected intracellular signaling networks and their role in cancer therapy. The focus will be on pathways for which inhibitory agents are currently undergoing clinical testing. Original data for inclusion in this review were identified through a MEDLINE search of the literature. All papers from 1966 through March 2005 were identified by the following search terms: “signal transduction,” “intracellular signaling,” “kinases,” “proliferation,” “growth factors,” and “cancer therapy.” All original research and review papers related to the role of intracellular signaling in oncogenesis and therapeutic interventions relating to abnormal cell signaling were identified. This search was supplemented by a manual search of the Proceedings of the Annual Meetings of the American Association for Cancer Research, American Society of Clinical Oncology, and the American Association for Cancer Research (AARC) –European Organisation for Research and Treatment of Cancer (EORTC) –National Cancer Institute (NCI) Symposium on New Anticancer Drugs.