Population pharmacokinetic analysis of 17-(allylamino)-17-demethoxygeldanamycin (17AAG) in adult patients with advanced malignancies

Purpose 17-(Allylamino)-17-demethoxygeldanamycin (17AAG) is a novel anticancer agent in clinical development. The objectives of this study were to develop a population pharmacokinetic model for 17AAG and its major metabolite, 17AG, and to investigate influences of patient characteristics and biochemical markers on pharmacokinetic parameters estimated for 17AAG and 17AG.Experimental design In a phase I clinical study, 17AAG was administered by intravenous infusion to 43 patients with refractory, advanced malignancies. Plasma concentrations of 17AAG and 17AG were determined by high-performance liquid chromatography. Plasma concentration vs time data were modeled using NONMEM. Nine covariates (age, sex, performance status, weight, height, body surface area, AST, bilirubin and serum creatinine) were investigated for their influences on individual pharmacokinetic parameters.Results Plasma concentration vs time data were best described by a two-compartment model for 17AAG and a one-compartment model for 17AG. Volumes of distribution were 24.2 and 89.6 l for 17AAG. Total elimination clearances were 26.7 and 21.3 l/h for 17AAG and 17AG, respectively. Both fixed and random effects pharmacokinetic parameters were well estimated. None of the covariates explained the interindividual variability in 17AAG and 17AG pharmacokinetic parameters or improved the fit of the model based on objective function changes.Conclusions A population pharmacokinetic model was developed to describe 17AAG and 17AG population pharmacokinetic parameters and interindividual variabilities. There were substantial interindividual variabilities in 17AAG and 17AG pharmacokinetic parameters despite BSA-normalized dosing.     

In vivo antitumor efficacy of 17-DMAG (17-dimethylaminoethylamino-17-demethoxygeldanamycin hydrochloride), a water-soluble geldanamycin derivative

Purpose To describe the preclinical basis for further development of 17-dimethyl aminoethylamino-17-demethoxygeldanamycin hydrochloride (17-DMAG, NSC 707545).Methods In vitro proliferation assays, and in vivo model studies in metastatic pancreatic carcinoma and subcutaneous xenograft melanoma and small-cell lung carcinoma models.Results 17-DMAG emerged from screening studies as a potent geldanamycin analog, with the average concentration inhibiting the growth of the NCI anticancer cell line drug screen by 50% being 0.053 M. Head to head comparison with 17-allylamino-17-demethoxygeldanamycin (17-AAG, NSC 330507) revealed 17-DMAG to possess potent activity against certain cell types, e.g., MDA-MB-231 breast carcinoma and HL60-TB leukemia which were relatively insensitive to 17-AAG. Evidence of oral bioavailability of 17-DMAG in a saline-based formulation prompted more detailed examination of its antitumor efficacy in vivo. 17-DMAG inhibited the growth of the AsPC-1 pancreatic carcinoma xenografts growing as intrahepatic metastases at doses of 6.7–10 mg/kg twice daily for 5 days administered orally under conditions where 17-AAG was without activity. 17-DMAG in an aqueous vehicle at 7.5–15 mg/kg per day for 3 days on days 1–3, 8–10 and 13–17, or 1–5 and 8–12 showed evidence of antitumor activity by the parenteral and oral routes in the MEXF 276 and MEXF 989 melanomas and by the parenteral route in the LXFA 629 and LXFS 650 adenocarcinoma and small-cell carcinoma models. The latter activity was comparable to the historical activity of 17-AAG.Conclusions Taken together, the in vivo activity of 17-DMAG supports the further development of this water-soluble and potentially orally administrable geldanamycin congener.     

Phase I trial of 17-dimethylaminoethylamino-17-demethoxygeldanamycin (17-DMAG), a heat shock protein inhibitor,administered twice weekly in patients with advanced malignancies

PurposePhase I dose-escalation study to determine the toxicity and maximum tolerated dose (MTD) of 17-dimethylaminoethylamino-17-demethoxygeldanamycin (17-DMAG), a heat shock protein 90 (Hsp90) inhibitor, administered on a twice weekly schedule in patients with advanced cancer.Experimental design17-DMAG was administered as a 1- to 2-h infusion twice weekly in 4-week cycles. An accelerated titration design was followed until toxicity was observed, at which point standard dose-escalation proceeded. MTD was defined as the dose at which no more than one of the six patients experienced a dose-limiting toxicity (DLT). Pharmacokinetics were assessed, and Hsp70 mRNA, whose gene product is a chaperone previously shown to be upregulated following the inhibition of Hsp90, was measured in peripheral blood mononuclear cells (PBMCs).ResultsA total of 31 patients received 92 courses of treatment. The MTD was 21 mg/m²/d; 20 patients were enrolled at this dose level. Nine patients had stable disease for a median of 4 (range 2–22) months. Both C_max and AUC increased proportionally with dose. The most common toxicities were grade 1 or 2 fatigue, anorexia, nausea, blurred vision and musculoskeletal pain. DLTs were peripheral neuropathy and renal dysfunction. Expression of Hsp70 mRNA in PBMCs was highly variable.ConclusionTwice-weekly i.v. infusion of 17-DMAG is well tolerated, and combination phase I studies are warranted.     

Phase I and pharmacologic study of 17-(allylamino)-17-demethoxygeldanamycin in adult patients with solid tumors.

PURPOSE: To determine the clinical toxicities of 17-(allylamino)-17-demethoxygeldanamycin (17-AAG) given as a 1-hour infusion daily for 5 days every 3 weeks. PATIENTS AND METHODS: Nineteen patients received 17-AAG over six dose levels (10 to 56 mg/m(2)) using an accelerated titration scheme. Drug levels of 17-AAG were determined by high-performance liquid chromatography. Biologic effects of 17-AAG were monitored by changes in the content of target proteins by immunoblot analysis of lysates prepared from peripheral-blood mononuclear cells. RESULTS: Toxicity was acceptable at doses up to 28 mg/m(2). The cohort was expanded to three patients at 40 mg/m(2) because a second occurrence of grade 2 hepatic transaminitis occurred. Two of six assessable patients who received 56 mg/m(2) had reversible, grade 3 hepatic transaminitis. Five additional patients were enrolled at 40 mg/m(2); none had dose-limiting toxicity. The maximum plasma concentrations (C(max)) of 17-AAG at 40 and 56 mg/m(2) were 1,724 and 2,046 ng/mL, respectively; the average plasma exposures (AUC) were 2,809 and 6,708 hours.ng/mL, respectively. Less than 3% of the daily dose was excreted into the urine. Clearance did not correlate with body-surface area. Possible biologic activity was suggested by apparent increased protein content of either glucose-related 78 kd protein or heat shock protein 70 with >/= 14 mg/m(2) and decreased protein content of either Lck or Raf1 with >/= 28 mg/m(2) of 17-AAG. CONCLUSION: 17-AAG 40 mg/m(2) (median dose, 70 mg) was well tolerated when given daily for 5 days every 3 weeks.     

Population pharmacokinetic analysis of free and bound aflibercept in patients with advanced solid tumors

Objective

Aflibercept (Zaltrap^®) is a novel antiangiogenic agent that binds to vascular endothelial growth factor (VEGF) and inhibits VEGF-dependent tumor growth. We aimed to characterize the population pharmacokinetics (PK) of free and bound aflibercept in patients with solid tumors to examine the influence of covariates on their PK and to evaluate the proposed dosing regimens by simulation.

Methods

Data from 9 clinical trials with 1,506 cancer patients receiving aflibercept (2–9 mg/kg every 2 or 3 weeks; 1 h IV infusion) as a monotherapy or in combination with various chemotherapies were included. Free and bound aflibercept concentrations were analyzed using a non-linear mixed-effects modeling approach with MONOLIX 4.1.2.

Results

An approximation of a target-mediated drug disposition model with irreversible binding of free aflibercept to VEGF adequately described the PK of free and bound aflibercept. The typical estimated clearances for free (CL _f ) and bound aflibercept (CL _b ) were 0.88 and 0.19 L/day, respectively. The volumes of distribution for free (V _p ) and bound (V _b ) aflibercept were similar (~4 L). CL _f and V _p increased with body weight and were lower in women. Patients with low albumin (ALB) or high alkaline phosphatase (ALK) had faster CL _f compared to a typical patient. Pancreatic cancer may be associated with changes in binding of aflibercept to VEGF. Simulations of different dosing regimens showed that adequate saturation of circulating VEGF was achieved with a dose of 4 mg/kg every 2 weeks.

Conclusions

Aflibercept kinetics was most affected by gender, body weight, ALB, ALK and pancreatic cancer. Simulations supported the rationale for the recommended dose of 4 mg/kg every 2 weeks for aflibercept.     

A phase 1 dose-escalation study of irinotecan in combination with 17-allylamino-17-demethoxygeldanamycin in patients with solid tumors

PURPOSE: Both heat shock protein 90 (Hsp90) and checkpoint kinase 1 (Chk1) have emerged as novel therapeutic targets. We conducted a phase I study of irinotecan and the Hsp90 inhibitor 17AAG, which can also down-regulate Chk1, in patients with solid tumors. EXPERIMENTAL DESIGN: During the dose escalation phase, patients received i.v. irinotecan followed by 17AAG once weekly for 2 weeks in a 21-day cycle. At the maximum tolerated dose (MTD), additional patients were enrolled to undergo pre- and post-17AAG tumor biopsies for pharmacodynamic evaluation. The pharmacokinetics of irinotecan, 17AAG, and their metabolites were characterized. Tumor p53 status as determined by immunohistochemistry was correlated with antitumor activity. RESULTS: Twenty-seven patients with a variety of solid tumors were enrolled. Four patients developed dose-limiting toxicity at dose level 4 (100 mg/m(2) irinotecan and 375 mg/m(2) 17AAG) including nausea, vomiting, diarrhea, and pulmonary embolism. The pharmacokinetics of 17AAG and its metabolite were not significantly affected by the coadministration of irinotecan, and vice versa. There was no partial response, although tumor shrinkage was observed in six patients. Five of 10 patients with p53-mutant tumor had stable disease as the best response compared with 2 of 6 patients with p53-wildtype tumor (P = 0.63). Evidence for Hsp90 inhibition by 17AAG, resulting in phospho-Chk1 loss, abrogation of the G(2)-M cell cycle checkpoint, and cell death could be shown in tumor biopsy samples obtained at the MTD. CONCLUSIONS: The combination of irinotecan and 17AAG can be given to patients with acceptable toxicity. The recommended phase II dose of the combination is 100 mg/m(2) irinotecan and 300 mg/m(2) 17AAG.     

Open-label, dose-escalation, safety, pharmacokinetic, and pharmacodynamic study of intravenously administered CNF1010 (17-(allylamino)-17-demethoxygeldanamycin [17-AAG]) in patients with solid tumors

Background

17-(Allylamino)-17-demethoxygeldanamycin (17-AAG) is a benzoquinone ansamycin that binds to and inhibits the Hsp90 family of molecular chaperones leading to the proteasomal degradation of client proteins critical in malignant cell proliferation and survival. We have undertaken a Phase 1 trial of CNF1010, an oil-in-water nanoemulsion of 17-AAG.

Methods

Patients with advanced solid tumors and adequate organ functions received CNF1010 by 1-h intravenous (IV) infusion, twice a week, 3 out of 4 weeks. Doses were escalated sequentially in single-patient (6 and 12 mg/m²/day) and three-to-six-patient (≥25 mg/m²/day) cohorts according to a modified Fibonacci’s schema. Plasma pharmacokinetic (PK) profiles and biomarkers, including Hsp70 in PBMCs, HER-2 extracellular domain, and IGFBP2 in plasma, were performed.

Results

Thirty-five patients were treated at doses ranging from 6 to 225 mg/m². A total of 10 DLTs in nine patients (2 events of fatigue, 83 and 175 mg/m²; shock, abdominal pain, ALT increased, increased transaminases, and pain in extremity at 175 mg/m²; extremity pain, atrial fibrillation, and metabolic encephalopathy at 225 mg/m²) were noted. The PK profile of 17-AAG after the first dose appeared to be linear up to 175 mg/m², with a dose-proportional increase in C _max and AUC_0–inf. Hsp70 induction in PBMCs and inhibition of serum HER-2 neu extracellular domain indicated biological effects of CNF1010 at doses >83 mg/m².

Conclusion

The maximum tolerated dose was not formally established. Hsp70 induction in PBMCs and inhibition of serum HER-2 neu extracellular domain indicated biological effects. The CNF1010 clinical program is no longer being pursued due to the toxicity profile of the drug and the development of second-generation Hsp90 molecules.     

Down-regulation of RIP expression by 17-dimethylaminoethylamino-17-demethoxygeldanamycin promotes TRAIL-induced apoptosis in breast tumor cells

The Hsp90 inhibitor 17DMAG (17-dimethylaminoethylamino-17-demethoxygeldanamycin) is undergoing clinical trials as an antitumor drug. We show here that treatment of human breast cancer cells with 17DMAG facilitates tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis. Down-regulation of receptor interacting protein (RIP1) is observed upon 17DMAG treatment concomitantly with inhibition of IκBα phosphorylation. Interestingly, RNAi-mediated knockdown of RIP1 expression is sufficient to sensitize human breast tumor cells to TRAIL-induced apoptosis through a NF-κB-independent, mitochondria-operated pathway. Our results indicate that RIP1 is important in maintaining resistance to TRAIL-induced apoptosis in breast tumor cells and highlight the potential therapeutic benefit of the combination of Hsp90 inhibitors and TRAIL against breast tumor cells.     

Comparison of 17-dimethylaminoethylamino-17-demethoxy-geldanamycin (17DMAG) and 17-allylamino-17-demethoxygeldanamycin (17AAG) in vitro: effects on Hsp90 and client proteins in melanoma models

The heat shock protein Hsp90 is a potential target for drug discovery of novel anticancer agents. By affecting this protein, several cell signaling pathways may be simultaneously modulated. The geldanamycin analog 17AAG has been shown to inhibit Hsp90 and associated proteins. Its clinical use, however, is hampered by poor solubility and thus, difficulties in formulation. Therefore, a water-soluble derivative was desirable and 17-dimethylaminoethylamino-17-demethoxy-geldanamycin (17DMAG) is such a derivative. Studies were carried out in order to evaluate the activity and molecular mechanism(s) of 17DMAG in comparison with those of 17-allylamino-demethoxygeldanamycin (17AAG). 17DMAG was found to be more potent than 17AAG in a panel of 64 different patient-derived tumor explants studied in vitro in the clonogenic assay. The tumor types that responded best included mammary cancers (six of eight), head and neck cancers (two of two), sarcomas (four of four), pancreas carcinoma (two of three), colon tumors (four of eight for 17AAG and six of eight for 17DMAG), and melanoma (two of seven). Bioinformatic comparisons suggested that, while 17AAG and 17DMAG are likely to share the same mode(s) of action, there was very little similarity with standard anticancer agents. Using three permanent human melanoma cell lines with differing sensitivities to 17AAG and 17DMAG (MEXF 276L, MEXF 462NL and MEXF 514L), we found that Hsp90 protein was reduced following treatment at a concentration associated with total growth inhibition. The latter occurred in MEXF 276L cells only, which are most sensitive to both compounds. The depletion of Hsp90 was more pronounced in cells exposed to 17DMAG than in those treated with 17AAG. The reduction in Hsp90 was associated with the expression of erbB2 and erbB3 in MEXF 276L, while erbB2 and erbB3 were absent in the more resistant MEXF 462NL and MEXF 514L cells. Levels of known Hsp90 client proteins such as phosphorylated AKT followed by AKT, cyclin D1 preceding cdk4, and craf-1 declined as a result of drug treatment in all three melanoma cell lines. However, the duration of drug exposure needed to achieve these effects was variable. All cell lines showed increased expression of Hsp70 and activated cleavage of PARP. No change in PI3K expression was observed and all melanoma cells were found to harbor the activating V599E BRAF kinase mutation. The results of our in vitro studies are consistent with both 17AAG and 17DMAG acting via the same molecular mechanism, i.e. by modulating Hsp90 function. Since 17DMAG can be formulated in physiological aqueous solutions, the data reported here strongly support the development of 17DMAG as a more pharmaceutically practicable congener of 17AAG.     

Preclinical toxicity of a geldanamycin analog, 17-(dimethylaminoethylamino)-17-demethoxygeldanamycin (17-DMAG), in rats and dogs: potential clinical relevance

Purpose 17-DMAG is a hydrophilic derivative of the molecular chaperone inhibitor 17-(allylamino)-17-demethoxygeldanamycin (17-AAG; NSC-330507), which is currently being evaluated for the treatment of cancer in clinical trials. 17-DMAG offers a potential advantage over 17-AAG because its aqueous solubility eliminates the need for complicated formulations that are currently used for administration of 17-AAG. In addition, 17-DMAG undergoes only limited metabolism compared to 17-AAG. The present results are from preclinical toxicity studies evaluating 17-DMAG in rats and dogs.Methods Doses of 0, 2.4, 12 and 24 mg/m² per day were administered to rats, while dogs received doses of 0, 8 or 16 mg/m² per day. In both species, 17-DMAG was administered i.v. (slow bolus for rats; 1-h infusion for dogs) daily for 5 days. An additional cohort of dogs received 16 mg/m² per day orally for 5 days. Clinical observations were noted, and standard hematology and clinical chemistry parameters were monitored. Selected tissues were evaluated microscopically for drug-related lesions. Tissue and plasma 17-DMAG concentrations were measured by HPLC/MS at selected time-points on days 1 and 5.Results Daily i.v. administration of 17-DMAG at doses of 24 mg/m² per day in rats or 16 mg/m² per day in dogs produced lethality on day 6, approximately 24 h following the last dose. Body weight loss was common in rats and dogs. Drug-related gastrointestinal, bone marrow and hepatic toxicities were also common in rats and dogs. Dogs also exhibited signs of renal and gallbladder toxicity. Plasma concentrations of 17-DMAG increased proportionately with dose in rats and disproportionately with dose in dogs. In rat tissues, however, only fourfold to sixfold increases in 17-DMAG concentrations were observed with a tenfold increase in dose. The highest concentrations of 17-DMAG were found in the liver of rats, with progressively lower concentrations in the spleen, lung, kidney and plasma. Regardless of the route of administration, higher drug concentrations were present in plasma (rat and dog) and tissue (rat) samples obtained on day 5 compared to those obtained on day 1. Although plasma concentrations decreased with time, 17-DMAG was still detected in dog plasma for at least 24 h after drug administration.Conclusions With the recent approval of 17-DMAG for clinical use, the data generated from these preclinical studies will provide guidance to clinicians as they administer this drug to their patients. The MTD of 17-DMAG was 12 mg/m² per day in rats and 8 mg/m² per day in dogs; therefore, the recommended starting dose for phase I trial is 1.3 mg/m² per day for 5 days. Gastrointestinal and bone marrow toxicity were dose-limiting in rats, and gastrointestinal, renal, gallbladder and bone marrow toxicity were dose-limiting in dogs. All adverse effects were fully reversible in surviving animals after treatment was complete.E.R. Glaze and A.L. Lambert contributed equally to this work.     

Phase I pharmacokinetic and pharmacodynamic study of 17-N-allylamino-17-demethoxygeldanamycin in pediatric patients with recurrent or refractory solid tumors: a pediatric oncology experimental therapeutics investigators consortium study.

PURPOSE: Heat shock protein 90 (Hsp90) is essential for the posttranslational control of many regulators of cell growth, differentiation, and apoptosis. 17-N-Allylamino-17-demethoxygeldanamycin (17-AAG) binds to Hsp90 and alters levels of proteins regulated by Hsp90. We conducted a phase I trial of 17-AAG in pediatric patients with recurrent or refractory neuroblastoma, Ewing's sarcoma, osteosarcoma, and desmoplastic small round cell tumor to determine the maximum tolerated dose, define toxicity and pharmacokinetic profiles, and generate data about molecular target modulation. EXPERIMENTAL DESIGN: Escalating doses of 17-AAG were administered i.v. over 1 to 2 h twice weekly for 2 weeks every 21 days until patients experienced disease progression or toxicity. harmacokinetic and pharmacodynamic studies were done during cycle 1. RESULTS: Fifteen patients were enrolled onto dose levels between 150 and 360 mg/m(2); 13 patients were evaluable for toxicity. The maximum tolerated dose was 270 mg/m(2). DLTs were grade 3 transaminitis and hypoxia. Two patients with osteosarcoma and bulky pulmonary metastases died during cycle 1 and were not evaluable for toxicity. No objective responses were observed. 17-AAG pharmacokinetics in pediatric patients were linear; clearance and half-life were 21.6 +/- 6.21 (mean +/- SD) L/h/m(2) and 2.6 +/- 0.95 h, respectively. Posttherapy increases in levels of the inducible isoform of Hsp70, a marker of target modulation, were detected in peripheral blood mononuclear cells at all dose levels. CONCLUSION: 17-AAG was well tolerated at a dose of 270 mg/m(2) administered twice weekly for 2 of 3 weeks. Caution should be used in treatment of patients with bulky pulmonary disease.     

Phase I and pharmacodynamic study of 17-(allylamino)-17-demethoxygeldanamycin in adult patients with refractory advanced cancers.

PURPOSE: The primary objective was to establish the dose-limiting toxicity (DLT) and recommended phase II dose of 17-(allylamino)-17-demethoxygeldanamycin (17AAG) given twice a week. EXPERIMENTAL DESIGN: Escalating doses of 17AAG were given i.v. to cohorts of three to six patients. Dose levels for schedule A (twice weekly x 3 weeks, every 4 weeks) were 100, 125, 150, 175, and 200 mg/m(2) and for schedule B (twice weekly x 2 weeks, every 3 weeks) were 150, 200, and 250 mg/m(2). Peripheral blood mononuclear cells (PBMC) were collected for assessment of heat shock protein (HSP) 90 and HSP90 client proteins. RESULTS: Forty-four patients were enrolled, 32 on schedule A and 12 on schedule B. On schedule A at 200 mg/m(2), DLTs were seen in two of six patients (one grade 3 thrombocytopenia and one grade 3 abdominal pain). On schedule B, both patients treated at 250 mg/m(2) developed DLT (grade 3 headache with nausea/vomiting). Grade 3/4 toxicities seen in >5% of patients were reversible elevations of liver enzymes (47%), nausea (9%), vomiting (9%), and headache (5%). No objective tumor responses were observed. The only consistent change in PBMC proteins monitored was a 0.8- to 30-fold increase in HSP70 concentrations, but these were not dose dependent. The increase in PBMC HSP70 persisted throughout the entire cycle of treatment but returned to baseline between last 17AAG dose of cycle 1 and first 17AAG dose of cycle 2. CONCLUSIONS: The recommended phase II doses of 17AAG are 175 to 200 mg/m(2) when given twice a week and consistently cause elevations in PBMC HSP70.     

A phase I study of 17-allylamino-17-demethoxygeldanamycin combined with paclitaxel in patients with advanced solid malignancies.

BACKGROUND: 17-Allylamino-17-demethoxygeldanamycin (17-AAG) inhibits heat shock protein 90, promotes degradation of oncoproteins, and exhibits synergy with paclitaxel in vitro. We conducted a phase I study in patients with advanced malignancies to determine the recommended phase II dose of the combination of 17-AAG and paclitaxel. METHODS: Patients with advanced solid malignancies that were refractory to proven therapy or without any standard treatment were included. 17-AAG (80-225 mg/m2) was given on days 1, 4, 8, 11, 15, and 18 of each 4-week cycle to sequential cohorts of patients. Paclitaxel (80-100 mg/m2) was administered on days 1, 8, and 15. Pharmacokinetic studies were conducted during cycle 1. RESULTS: Twenty-five patients were accrued to five dose levels. The median number of cycles was 2. Chest pain (grade 3), myalgia (grade 3), and fatigue (grade 3) were dose-limiting toxicities at dose level 4 (225 mg/m2 17-AAG and 80 mg/m2 paclitaxel). None of the six patients treated at dose level 3 with 17-AAG (175 mg/m2) and paclitaxel (80 mg/m2) experienced dose-limiting toxicity. Disease stabilization was noted in six patients, but there were no partial or complete responses. The ratio of paclitaxel area under the concentration to time curve when given alone versus in combination with 17-AAG was 0.97 +/- 0.20. The ratio of end-of-infusion concentration of 17-AAG (alone versus in combination with paclitaxel) was 1.14 +/- 0.51. CONCLUSIONS: The recommended phase II dose of twice-weekly 17-AAG (175 mg/m2) and weekly paclitaxel (80 mg/m2/wk) was tolerated well. There was no evidence of drug-drug pharmacokinetic interactions.     

Phase I and pharmacokinetic study of polymeric micelle-formulated paclitaxel in adult Chinese patients with advanced solid tumors

Purpose

Polymeric micelle-formulated paclitaxel (PM paclitaxel) is a nanoscale drug delivery compound. This study investigated the maximum tolerated dose (MTD), dose-limiting toxicities, and pharmacokinetic (PK) profile of PM paclitaxel in Chinese patients with treatment-refractory advanced or relapsed solid tumors.

Methods

Dose escalation of PM paclitaxel followed the standard ‘3 + 3’ rule, starting at 175 mg/m². PM paclitaxel was administered over 3 h every 3 weeks. Patients were treated until disease progression, intolerance, death, or consent withdrawal. Blood samples were collected for PK testing.

Results

All 23 patients were evaluable for toxicity. Neutropenia, neuropathy, and myalgia were the most common toxicities; acute hypersensitivity reaction was not observed. One of six patients at dose level 4 (350 mg/m²) and two of six patients at dose level 5 (390 mg/m²) developed grade 4 neutropenia. The MTD was 350 mg/m². No patients discontinued treatment because of neuropathy. Partial response was seen in five of 20 patients (25 %) who had response assessment, three of whom had prior exposure to taxanes (two were heavily pretreated). Ten patients (50 %) had stable disease at cycle 2 and only five patients (25 %) had disease progression. The area under the curve and the maximum concentration of paclitaxel increased with escalating doses, suggesting that PM paclitaxel has linear PKs.

Conclusions

The main dose-limiting toxicity for PM paclitaxel was neutropenia, and the recommended dose for phase II study is 300 mg/m². PM paclitaxel is superior to conventional paclitaxel for its simplified premedication regimen and delivery of a higher paclitaxel dose without increased neuropathy.     

Population pharmacokinetics of cabazitaxel in patients with advanced solid tumors

Purpose

To develop a population pharmacokinetic (PK) model for cabazitaxel in patients with advanced solid tumors and examine the influence of demographic and baseline parameters.

Methods

One hundred and seventy patients who received cabazitaxel (10–30 mg/m², 1-h IV infusion) every 7 or 21 days in five Phase I–III studies were analyzed by non-linear mixed-effect modeling (NONMEM VI). Model evaluation comprised non-parametric bootstrap and visual predictive checks.

Results

Cabazitaxel PK was best described by a linear three-compartment model with: first-order elimination; interindividual variability on clearance (CL), central volume of distribution (V1), and all intercompartmental rate constants except K21; interoccasion variability in CL and V1; proportional residual error of 27.8 %. Cabazitaxel CL was related to body surface area (BSA) and tumor type (breast cancer; finding confounded by study). Typical CL for a non-breast cancer patient with a BSA of 1.84 m² was 48.5 L/h, with V1 26.0 L, steady-state volume of distribution 4,870 L and alpha, beta, and gamma half-lives of 4.4 min, 1.6, and 95 h, respectively. Sex, height, weight, age, Caucasian race, renal/hepatic function, and cytochrome P450 inducer use did not significantly further explain the PK of cabazitaxel. Bootstrap and posterior predictive checks confirmed the adequacy of the model.

Conclusions

Cabazitaxel PK appears unaffected by most baseline patient factors, and the influence of BSA on CL is addressed in practice by BSA-dependent doses. This analysis suggests consistent cabazitaxel PK and exposure across most solid tumor types, although the potential influence of breast cancer on CL requires further confirmation.     

Phase I and pharmacokinetic study of vorinostat (suberoylanilide hydroxamic acid) in Japanese patients with solid tumors

Vorinostat (suberoylanilide hydroxamic acid), a potent, oral histone deacetylase inhibitor, has demonstrated clinical activity in non-Japanese patients with various hematological and solid tumors. We sought to determine the maximum tolerated dose and a recommended phase II dose for 18 Japanese patients with solid tumors (median age, 58 years; range, 25–72 years) who failed standard therapy. Patients received vorinostat for 14 days followed by a 7-day rest. The initial dose was 100 mg twice daily escalating by 100 mg twice daily. Once-daily dosing was tested at 400 and 500 mg. A maximum tolerated dose could not be identified. Dose-limiting toxicities (thrombocytopenia, anorexia, and fatigue) were observed in two of six patients receiving 200 mg twice daily and in one of six patients receiving 500 mg once daily. In the 100–500 mg dose range, vorinostat area under the concentration–time curve increased in proportion to dose with a pharmacokinetic profile similar to that established in non-Japanese patients. Vorinostat doses of 200 mg twice daily or 500 mg once daily for 14 days followed by a 7-day rest were well tolerated and are candidate doses for phase II trials, although a maximum tolerated dose for vorinostat was not reached. ( Cancer Sci 2009; 100: 1728–1734)     

A phase I and pharmacokinetic study of elisidepsin (PM02734) in patients with advanced solid tumors

Purpose

To determine the maximum-tolerated dose (MTD), dose-limiting toxicity (DLT), and recommended phase II dose (RD) of elisidepsin.

Methods

Eligible patients with refractory, advanced solid tumors received elisidepsin as 24-h intravenous infusion every 3?weeks. Pharmacokinetic profiles were analyzed during cycles 1 and 2.

Results

Forty-two patients received elisidepsin at doses from 0.5 to 6.8?mg/m². The MTD was 6.8?mg/m², and the RD was 5.5?mg/m². Cohort expansion at the RD was done at a fixed dose (FD) of 10?mg, considered equivalent to 5.5?mg/m². DLTs (reversible grade 3 transaminase increases) occurred at 6.8?mg/m² (n?=?2 patients), 5.5?mg/m² (n?=?1), and 10?mg FD (n?=?1). One patient with esophageal adenocarcinoma achieved complete response for >38?months, and 12 patients had disease stabilization (8 for ≥3?months). Median time-to-progression for these 12 patients was 4.8?months. Plasma elisidepsin concentrations increased with dose. No drug accumulation between cycles was found. No correlation was observed between body surface area (BSA) and plasma clearance; therefore, elisidepsin was given as flat dose (in mg) in the expansion cohort at the RD and in ongoing clinical trials.

Conclusions

Elisidepsin is well tolerated with predictable reversible transaminase increases. Encouraging preliminary evidence of antitumor activity was observed.