Quantified tumor t1 is a generic early-response imaging biomarker for chemotherapy reflecting cell viability

PURPOSE

Identification of a generic response biomarker by comparison of chemotherapeutics with different action mechanisms on several noninvasive biomarkers in experimental tumor models.

EXPERIMENTAL DESIGN

The spin-lattice relaxation time of water protons (T(1)) was quantified using an inversion recovery-TrueFISP magnetic resonance imaging method in eight different experimental tumor models before and after treatment at several different time points with five different chemotherapeutics. Effects on T(1) were compared with other minimally invasive biomarkers including vascular parameters, apparent diffusion coefficient, and interstitial fluid pressure, and were correlated with efficacy at the endpoint and histologic parameters.

RESULTS

In all cases, successful chemotherapy significantly lowered tumor T(1) compared with vehicle and the fractional change in T(1) (DeltaT(1)) correlated with the eventual change in tumor size (range: r(2) = 0.21, P < 0.05 to r(2) = 0.73, P < 0.0001), except for models specifically resistant to that drug. In RIF-1 tumors, interstitial fluid pressure was decreased, but apparent diffusion coefficient and permeability increased in response to the microtubule stabilizer patupilone and 5-fluorouracil. Although DeltaT(1) was small (maximum of -20%), the variability was very low (5%) compared with other magnetic resonance imaging methods (24-48%). Analyses ex vivo showed unchanged necrosis, increased apoptosis, and decreased %Ki67 and total choline, but only Ki67 and choline correlated with DeltaT(1). Correlation of Ki67 and DeltaT(1) were observed in other models using patupilone, paclitaxel, a VEGF-R inhibitor, and the mammalian target of rapamycin inhibitor everolimus.

CONCLUSIONS

These results suggest that a decrease in tumor T(1) reflects hypocellularity and is a generic marker of response. The speed and robustness of the method should facilitate its use in clinical trials.

Metabolic implications of dietary trans-fatty acids

Dietary trans-fatty acids are associated with increased risk of cardiovascular disease and have been implicated in the incidence of obesity and type 2 diabetes mellitus (T2DM). It is established that high-fat saturated diets, relative to low-fat diets, induce adiposity and whole-body insulin resistance. Here, we test the hypothesis that markers of an obese, prediabetic state (fatty liver, visceral fat accumulation, insulin resistance) are also worsened with provision of a low-fat diet containing elaidic acid (18:1t), the predominant trans-fatty acid isomer found in the human food supply. Male 8-week-old Sprague-Dawley rats were fed a 10% trans-fatty acid enriched (LF-trans) diet for 8 weeks. At baseline, 3 and 6 weeks, in vivo magnetic resonance spectroscopy (1H-MR) assessed intramyocellular lipid (IMCL) and intrahepatic lipid (IHL) content. Euglycemic-hyperinsulinemic clamps (week 8) determined whole-body and tissue-specific insulin sensitivity followed by high-resolution ex vivo 1H-NMR to assess tissue biochemistry. Rats fed the LF-trans diet were in positive energy balance, largely explained by increased energy intake, and showed significantly increased visceral fat and liver lipid accumulation relative to the low-fat control diet. Net glycogen synthesis was also increased in the LF-trans group. A reduction in glucose disposal, independent of IMCL accumulation was observed in rats fed the LF-trans diet, whereas in rats fed a 45% saturated fat (HF-sat) diet, impaired glucose disposal corresponded to increased IMCLTA. Neither diet induced an increase in IMCLsoleus. These findings imply that trans-fatty acids may alter nutrient handling in liver, adipose tissue, and skeletal muscle and that the mechanism by which trans-fatty acids induce insulin resistance differs from diets enriched with saturated fats.

Effects of cevoglitazar, a dual PPARalpha/gamma agonist, on ectopic fat deposition in fatty Zucker rats

AIM

By acting as both insulin sensitizers and lipid-lowering agents, dual-acting peroxisome proliferator-activated receptors alpha/gamma (PPARalpha/gamma) agonists may be used to improve glucose tolerance in type 2 diabetic patients without inducing adiposity and body weight gain. Here, in an animal model of obesity and insulin resistance, the metabolic response to cevoglitazar, a dual PPARalpha/gamma, was characterized using a combination of in vivo and ex vivo magnetic resonance methodologies and compared to treatment effects of fenofibrate, a PPARalpha agonist, and pioglitazone, a PPARgamma agonist.

METHODS

Four groups of fatty Zucker rats: (i) Vehicle; (ii) fenofibrate 150 mg/kg; (iii) pioglitazone 30 mg/kg; and (iv) cevoglitazar 5 mg/kg were investigated before and after treatment. Animals were fed a fat-enriched (54% kcal fat) diet for 6 weeks, 2 weeks high of fat-exposure alone followed by a 4-week dosing period.

RESULTS AND CONCLUSIONS

Cevoglitazar was as effective as pioglitazone at improving glucose tolerance. However, unlike pioglitazone, both fenofibrate and cevoglitazar reduced BW gain and adiposity, independent of food intake. All three treatment regimens normalized intramyocellular lipids. Metabolic profiling showed that in the muscle cevoglitazar improves the lipid profile via both PPARalpha- and PPARgamma-mediated mechanisms. Pioglitazone reduced hepatic lipid accumulation, while cevoglitazar and fenofibrate reduced hepatic lipid concentration below baseline levels (p < 0.05). Metabolic profiling showed that in the liver, cevoglitazar functions largely through PPARalpha agonism resulting in increased beta-oxidation. Cevoglitazar only induced small changes to the lipid composition of visceral fat. In subcutaneous fat, however, cevoglitazar induced changes similar to those observed with fenofibrate suggesting export of fatty acids from this depot.

Insulin-stimulated mitochondrial adenosine triphosphate synthesis is blunted in skeletal muscles of high-fat-fed rats

Physiologic elevation of insulin levels induces a significant increase in muscle adenosine triphosphate (ATP) synthesis rate in normal individuals, indicative of an appropriate acceleration in mitochondrial activity. However, the stimulatory effect of insulin is diminished in insulin-resistant patients. In the absence of similar data from preclinical models, the present study investigated the inhibitory effects of increased dietary fat intake on insulin-stimulated ATP synthesis rates in rats. After being placed on a high-fat diet for 8 weeks (n = 10), diet-induced obese male Sprague-Dawley rats were tested against age-matched control rats (n = 9) on a normal chow diet. Muscle ATP synthase flux rates were measured under anesthesia by in vivo (31)P saturation transfer both before and during a euglycemic-hyperinsulinemic clamp. The glucose infusion rates observed during the clamp revealed impaired peripheral insulin sensitivity in the high-fat-fed rats when compared with the age-matched control rats. Under baseline conditions (ie, low insulin), the muscle ATP synthesis rates of high-fat-fed rats were approximately 30% lower (P < .05) than those in chow-fed rats. Moreover, chow-fed animals showed a significant increase (25%, P < .05 vs basal) in muscle ATP synthesis activity upon insulin stimulation, whereas high-fat-fed animals displayed no substantial change. These data demonstrated for the first time in a preclinical model that the insulin challenge not only facilitates an improvement in the dynamic range of ATP turnover measurement by (31)P saturation transfer between normal and insulin-resistant rats, but also mimics challenge that is relevant for pharmacologic studies on antidiabetic drugs aimed at improving mitochondrial function.

Effect of dexamethasone on glucose tolerance and fat metabolism in a diet-induced obesity mouse model

Prolonged exposure to elevated glucocorticoid levels is known to produce insulin resistance (IR), a hallmark of diabetes mellitus. Although not fully elucidated, the underlying molecular mechanisms by which glucocorticoids induce IR may provide potential targets for pharmacological interventions. Here we characterized muscle lipid metabolism in a dexamethasone-aggravated diet-induced obesity murine model of IR. Male C57BL/6 mice on a high-fat diet for 2 months when challenged with dexamethasone showed elevated food consumption and weight gain relative to age and diet-matched animals dosed with saline only. Dexamethasone treatment impaired glucose tolerance and significantly increased the intramyocellular lipid content in the tibialis anterior muscle (TA). A good correlation (r = 0.76, P < 0.01) was found between accumulation in intramyocellular lipid content in the TA and visceral adiposity. The linoleic acid (18:2) to polyunsaturated acid ratio was increased in the dexamethasone-treated animals (+29%; P < 0.01), suggesting a possible increase in stearoyl-CoA desaturase 2 activity, as reported in Sertoli cells. The treatment was also accompanied by a reduction in the percent fraction of omega-3 and long-chain polyunsaturated fatty acids in the TA. Analysis of the low-molecular-weight metabolites from muscle extracts showed that there was no dysregulation of muscle amino acids, as has been associated with dexamethasone-induced muscle proteolysis. In conclusion, dexamethasone-induced insulin resistance in diet-induced obese mice is associated with a profound perturbation of lipid metabolism. This is particularly true in the muscle, in which an increased uptake of circulating lipids along with a conversion into diabetogenic lipids can be observed.

Diet-induced modulation of mitochondrial activity in rat muscle

Growing evidence supports the theory that mitochondrial dysfunction is an underlying cause of intramyocellular lipid (IMCL) accumulation and insulin resistance. Here, we hypothesized that high dietary fat (HF) intake could trigger changes in mitochondrial activity such that fatty acid oxidation is impaired in muscle and contributes to an elevation in intramyocellular lipid (IMCL) levels. Muscle mitochondrial activity was determined in vivo through measurement of the F(1)F(0) ATP synthase flux, the terminal step in the oxidative phosphorylation process. An initial study comparing rats on normal chow diet with rats on an HF diet revealed strong correlations between muscle ATP synthesis rates, IMCL levels and whole body glucose tolerance. Results obtained from two latter studies showed multiphasic responses to dietary intervention. Initially, the ATP synthesis rates decreased as much as 50% within 24 h of raising the fat content in the diet to 60% of the caloric intake. These rates eventually returned to normal values after 2-3 wk on the HF regimen, seemingly to prevent further IMCL accumulation. Only beyond 1 mo on the HF diet did results consistently show ATP synthesis rates to diminish by 30-50% accompanied by steadily augmenting IMCL levels. Interestingly, switching back to a chow diet after 3 wk of HF feeding reversed the initial diet-induced changes. Although the muscle mitochondrial system may initially offer enough compliance to counteract lipid surplus, these in vivo data suggest a vicious long-term cycle among mitochondrial dysfunction, IMCL accumulation, and glucose intolerance in the rat.

Phase II, open-label study of PTK787/ZK222584 for the treatment of metastatic gastrointestinal stromal tumors resistant to imatinib mesylate

BACKGROUND

We evaluated safety and efficacy of PTK787/ZK222584 (PTK/ZK), a novel tyrosine kinase inhibitor of KIT, platelet-derived growth factor receptors and vascular endothelial cell growth factor receptors (VEGFRs), in patients with imatinib-resistant gastrointestinal stromal tumor (GIST). This is the first study of PTK/ZK in this population.

PATIENTS AND METHODS

Patients with metastatic GIST that had progressed after >/= 4-week treatment with imatinib mesylate were eligible. Prior VEGFR-2 inhibitor therapy was not permitted. PTK/ZK 1250 mg orally once-daily was administered to 15 patients (accrued as a two-stage procedure), most of whom (n = 11) had been unsuccessfully treated with imatinib 800 mg daily, until treatment failure. Patients were monitored at 4- to 8-week intervals.

RESULTS

All 15 patients enrolled were eligible; two (13%) achieved partial response (PR), eight (53%) had stable disease (SD) >/=3 months, and five (33%) progressed. The clinical benefit rate (PR + SD) was 67% (95% CI 38% to 86%). Median time to progression was 8.5 months (range 0.9-24.8+ months). Three patients had not progressed at the time of analysis, including one PR at 24.8 months and two SDs at 16.6 and 18.6 months on treatment. PTK/ZK was generally well tolerated.

CONCLUSION

PTK/ZK 1250 mg p.o. once daily is active and well tolerated in patients with imatinib-resistant GIST.

Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) as a biomarker for the effect of PTK787/ZK 222584 (PTK/ZK) as second-line mono-therapy in patients with stage IIIB or stage IV non-small cell lung cancer (NSCLC)

7676

Background: Overexpression of vascular endothelial growth factor receptor (VEGF-R) in NSCLC-tumors is linked to poor prognosis and shorter overall survival. PTK/ZK (PTK/ZK) is a novel, oral, anti-angiogenic compound blocking all currently known VEGF receptors (VEGF-R1–3). DCE-MRI measures early changes in tumour-associated vasculature in response to treatment and has been successfully used as a biomarker for biological activity of PTK/ZK in liver metastases from colorectal cancer. Methods: This is a prospective, multi- centre, phase-II study of PTK/ZK in pretreated patients with advanced stage NSCLC. 54 patients (pts) received 1,250 mg PTK/ZK once daily (qd), followed by 58 patients receiving 1,250 mg (500 am + 750 mg pm) PTK/ZK twice daily (bid). Response evaluation was based on RECIST. Disease stabilization of at least 12 weeks based on CT/MRI-imaging was defined as clinically relevant drug activity. DCE-MRI was performed 2- 4 hours after PTK/ZK administration, on day 2 and at day 28. Contrast enhancement for the whole tumour was assessed by calculating the transfer constant (Ktrans) using a two-compartment model. Results: DCE-MRI was performed successfully in 35 pts in the qd cohort on day 2 and 29 pts in the qd cohort at day 28. There was a statistically significant mean reduction in Ktrans at day 2 of 35.2 % (p<0.0001, N=35, paired ‘t’ test) and at Day 28 of 38.1% (p<0.0001, N=29). 32 pts with day 2 DCE- MRI were evaluable for response assessment with 10 (31%) achieving SD at 12 weeks and 22 (69%) with progressive disease (PD). Both the SD group and the PD group had significant mean reductions in Ktrans at day 2 (39.4% and 37.1%, respectively). However, the difference between SD and PD was not statistically significant. Data for the bid cohort will be presented at the meeting. Conclusions: PTK/ZK causes statistically significant reduction in tumour vascular parameters of lung tumours. Ktrans has previously been shown to correlate with clinical outcome. However, for the qd cohort, no correlation could be demonstrated. This may be due to the limitation of the sample size as well as the heterogeneity of the targeted lesions selected for this study.

[Table: see text]

Phase II open-label study to investigate efficacy and safety of PTK787/ZK 222584 (PTK/ZK) orally administered once daily or twice daily at 1,250 mg as second-line monotherapy in patients (pts) with stage IIIB/IV non-small cell lung cancer (NSCLC)

7541

Background: Overexpression of vascular endothelial growth factor receptor (VEGF-R) in NSCLC-tumors is linked to poor prognosis and shorter overall survival (OS). PTK/ZK is a novel, oral, anti-angiogenic compound blocking all currently known VEGF receptors (VEGF-R 1–3). Methods: A prospective, single-arm, multi-center, proof-of-principle phase II study to investigate efficacy and safety of PTK/ZK in pretreated pts with stage IIIB/IV NSCLC. Only one platinum-based chemotherapy regimen was allowed as first-line treatment. 55 pts each were planned to receive a fixed dose of 1,250 mg PTK/ZK once daily (qd) or twice daily (500 mg a.m. + 750 mg p.m.) (bid) for continuous treatment until disease progression or unacceptable toxicities. Response evaluation was based on RECIST. A disease stabilization of at least 12 weeks was defined as clinically relevant drug activity. Additional biomarker evaluation included DCE-MRI and serum proteomics. Results: Enrolment is completed with 54 pts starting qd and 58 pts starting bid treatment. Most frequent adverse events in both cohorts were nausea (44%), vomiting (40%), and dizziness (34%). Three possibly related deaths were observed, 2 due to pulmonary hemorrhage and 1 due to pulmonary embolism. Best response by RECIST for the qd cohort (n=54) include 1 pt with a confirmed partial response (cPR) (2%), 32 pts (59%) with stable disease (SD) at week 4, hereof 18 pts (33%) for at least 12 weeks, and 21 pts (39%) with progressive disease (PD); for the bid cohort (n=57) 4 pts with cPR (7%), 18 pts (32%) with SD (=12 weeks), 19 pts (33%) not yet evaluated, and 16 pts (28%) with PD. Progression free survival (PFS)/OS were 2.4/7.0 months (mo) for the qd vs. 3.7/6.8 mo for the bid cohort. Conclusions: These results suggest that both qd and bid second-line treatment with single-agent PTK/ZK is generally safe and well tolerated. In this unfavorable pt population a considerably high rate of disease control could be achieved. Four pts with PR out of 38 evaluated pts in the bid cohort might indicate additional benefit of bid dosing. Final data of the primary endpoint (efficacy) for both cohorts will be presented at the meeting.

[Table: see text]

Phase I and pharmacokinetic (PK) study of PTK787/ZK222584 (PTK/ZK) plus capecitabine (cape) in patients (Pts) with advanced cancer

3595

Background: PTK/ZK is a small molecule inhibitor of the vascular endothelial growth factor receptor family. Cape is a standard treatment for pts with breast and colon cancer, tumors for which angiogenesis inhibition is beneficial. Therefore, we conducted a phase I study of the combination to determine the maximally tolerated doses (MTD), toxicities and PK interactions. Methods: Eligible pts had advanced cancer with no standard treatment option, Karnofsky performance status (KPS) > 70, and normal organ function. Pts with bone marrow or CNS involvement or who had more than 4 prior chemotherapy regimens were excluded. A dose escalation (dosesc) phase was conducted to determine the MTD followed by a dose expansion (dosexp) phase to assess PK interactions. PTK/ZK was given as a single oral daily doser without interruption and cape was given orally twice daily for 14 of 21 days. Results to Date: 43 pts (30 male, 13 female), median age 61 y (34–78 y) and median KPS 95 (70–100) were enrolled in the dosesc phase. 37 had prior chemotherapy; 5 had radiation only. Diagnoses included colorectal cancer (10), head/neck (7), sarcoma (5), renal (4), stomach/pancreas (3 each) and others (11). 29/43 pts were evaluable for MTD determination and received a total of 145 cycles. Doses of PTK/ZK-cape (mg-mg/m2) were: 750/2,500; 1,000/2,500; 750/2,000; 1,000/2,000; 1,250/2,000. DLT occurred in 1/6 pts (gr 3 fatigue) at 750/2,500; 2/2 pts (≥gr 3 fatigue, hypertension [HTN]) at 1,000/2,500; 0/3 pts at 750/2,000; 2/12 pts (≥ gr 3 dizziness, HTN and seizure) at 1,000/2,000 and in 1/6 (gr 3 proteinuria) pts at 1,250/2,000. 1,250 mg was the highest PTK/ZK dose planned. Other common toxicities in the dosesc phase were hand-foot syndrome (HFS, 93%) and HTN (28%). In the dosexp phase 26 pts (14 M, 12 F) have thus far received 73 cycles at the MTD (1,250/2,000). Median age is 65 y (26–79 y) and median KPS is 80 (70–100). 28/73 cycles were delayed or interrupted for toxicity with gr ≥3 toxicities (# cycles): HFS (7), fatigue (5), increased LFTs (5), HTN (3), DVT/PE (4). 23 pts (17 in dosesc and 6 in dosexp) had response or stable disease longer than 12 weeks. Final results and PK data will be presented. Conclusion: PTK/ZK and cape can be combined without unexpected toxicities.

No significant financial relationships to disclose.

A phase IB, open-label dose-escalating study of the oral angiogenesis inhibitor PTK787/ZK 222584 (PTK/ZK), in combination with FOLFOX4 chemotherapy in patients with advanced colorectal cancer

BACKGROUND

This open-label, phase IB study was undertaken to determine the safety/toxicity profile and recommended dose of oral once-daily PTK787/ZK 222584 (PTK/ZK) combined with oxaliplatin/5-fluorouracil (5-FU)/leucovorin (FOLFOX4) chemotherapy in patients with advanced colorectal cancer. Secondary objectives were to assess full pharmacokinetics and gather preliminary evidence of antitumor activity.

PATIENTS AND METHODS

Thirty-five patients received escalating doses of PTK/ZK (range 500-2000 mg daily) continuously. Concurrent FOLFOX4 chemotherapy was administered on days 1 and 2 and repeated every 14 days. Dose escalation of PTK/ZK was continued until maximum tolerated dose (MTD) was established and additional patients were then enrolled at MTD dosage.

RESULTS

Mean treatment duration of PTK/ZK was 9.5 months. The MTD was 1250 mg daily with dizziness being the most frequent dose-limiting toxicity (DLT). Hypertension (23%, grade 3) and neutropenia (37%, grades 3 + 4) were the most frequent grade 3 or 4 adverse events. Pharmacokinetic analyses found no evidence for interactions between PTK/ZK and the combination of 5-FU, leucovorin, and oxaliplatin during concomitant use. Median progression-free survival was 11.4 months.

CONCLUSION

The MTD of PTK/ZK in combination with FOLFOX4 in this patient population is 1250 mg daily. The combination is feasible and safe and is not associated with significant pharmacokinetic interactions.

In vivo MRI of cartilage pathogenesis in surgical models of osteoarthritis

OBJECTIVE

To examine in vivo time-course changes in macromolecular composition of articular cartilage in two surgical models of osteoarthritis (goat: meniscal transection and cartilage incision; rabbit: medial meniscectomy).

DESIGN

Collagen integrity and proteoglycan (PG) content were evaluated in both models by magnetization transfer (MT) and contrast-enhanced MRI, respectively. The MT rate k(m) for the exchange process between the bulk water and water bound to collagen was determined as a marker of the collagen network. Local changes in cartilage fixed charge density, i.e., where PGs are depleted, were derived from T(1) relaxation maps as obtained after an infusion of Gd(DTPA)(2-), a paramagnetic agent.

RESULTS

In the goat model, the MT rate constant k(m) was significantly higher at 2 weeks post surgery, a possible sign of cartilage swelling, then decreased below baseline values, most likely indicative of disruption in the collagen framework. Meanwhile, post-Gd(DTPA)(2-) MRI acquisition indicated a significant and sustained loss of PGs. The rabbit model produced milder lesions. Although the difference was non-significant, k(m) steadily decreased in response to the surgical insult while kinetics of Gd(DTPA)(2-) uptake, after reaching a peak level at 6 weeks, were back to normal values after 12 weeks.

CONCLUSION

In the goat model, joint instability and cartilage damage was a permanent trigger for cartilage degeneration producing MRI changes. However, biomechanical stress due to partial medial meniscectomy in knees of mature rabbits produced only mild, focal lesions and PG depletion that was partially reversible. This proof-of-concept study identified MT and T(1) parameters as useful surrogate markers in animal models of osteoarthritis.

Phase II open-label study to investigate efficacy and safety of PTK787/ZK 222584 orally administered once daily at 1,250 mg as second-line monotherapy in patients (pts) with stage IIIB or stage IV non-small cell lung cancer (NSCLC)

7195

Background: Overexpression of vascular endothelial growth factor receptor (VEGF-R 1–3) in NSCLC is associated with poor prognosis and shorter overall survival. PTK787/ZK 222584 (PTK/ZK), a novel, oral, anti-angiogenic compound blocks tyrosine kinase signaling from all VEGF receptors. Methods: A prospective, single-arm, multi-center, proof-of-principle phase-II study to investigate both efficacy and safety of PTK/ ZK in patients with stage IIIB/IV NSCLC who received prior first line treatment with a platinum based chemotherapy regimen. All pts were relapsed/refractory as determined by available imaging. All pts were planned to receive 1,250 mg of PTK/ZK once daily (qd) for continuous treatment until disease progression or unacceptable toxicities. Response evaluation is based on RECIST criteria. Disease stabilization of at least 12 weeks based on CT/MRI-imaging was defined as clinically relevant drug activity. All pts had dynamic contrast enhanced MRI investigations for additional efficacy analysis and serum asservations for serum proteomic analysis. Results: To date, 56 pts have been enrolled. PTK/ZK is generally well tolerated. Most frequent adverse events (AEs) are nausea and vomiting. One pt developed interstitial lung disease (ILD) and in one pt with tracheal stent a fatal lung bleeding occurred. No other unexpected serious AEs have been reported. Maximum response for 48 evaluated pts include one pt with a partial response (PR) (2%), 27 pts with stable disease (SD) (56%), (disease control rate 58%), and 20 pts with progressive disease (PD) (42%). The pt with PR has responded for over 20 weeks. 15 pts have SD for at least 12 weeks; 5 pts of these had SD for at least 28 weeks. Conclusions: These preliminary results suggest that second-line treatment with single-agent PTK/ZK is generally safe and well tolerated. In pts with refractory disease in stage IIIB/IV NSCLC, a considerably high rate of disease control could be achieved in this study. The study is currently recruiting for twice daily (bid) treatment.

[Table: see text]

A phase IB, open label, safety and pharmacokinetic (PK) study of escalating doses of PTK787/ZK 222584 (PTK/ZK) in combination with paclitaxel and carboplatin in patients (Pts) with stage IC to IV epithelial ovarian cancer (EOC)

5075

Background: Vascular endothelial growth factors (VEGFs) and VEGF receptors (VEGFRs) are important mediators of tumor growth and metastasis and their expression is associated with poor prognosis in EOC. PTK/ZK is a novel, oral, angiogenesis and lymphangiogenesis inhibitor that blocks tyrosine kinase signaling from all known VEGFRs. Methods: An open label, multicenter, phase IB dose escalation study evaluating PTK/ZK with chemotherapy as first line therapy in Pts with stage IC to IV EOC. Maximum tolerated dose (MTD) and dose limiting toxicity (DLT) of PTK/ZK were assessed; PK of PTK/ZK, carboplatin and paclitaxel was characterized. Paclitaxel was administered as a 3-hour infusion on day 1 of each 21-day cycle at a dose of 175 mg/m2. Carboplatin was given immediately after paclitaxel as a 30-min IV infusion to AUC of 5 mg min/mL. PTK/ZK was given once daily from day 3 to day 21 of each chemotherapy cycle. Cohorts of 3 to 6 Pts received doses of PTK/ZK at 250, 500, 750, 1000 or 1250 mg/day. Dose expansion in 21 additional Pts was conducted with 1250 mg/day without reaching MTD. After completion of chemotherapy, PTK/ZK was given continuously until disease progression. PK samples were collected in cycle 1 (without PTK/ZK) and cycle 2 (after PTK/ZK pre-treatment). Results: 42 Pts were enrolled. To date 39 Pts are evaluated for safety, 19 Pts for DLT, 35 Pts for PK and 21 Pts with residual disease for tumor response. No DLTs were reported. The most frequently observed grade 3/4 toxicity was neutropenia (31%), leucopenia (18%) and hypertension (10%). PTK/ZK did not aggravate chemotherapy related side effects. To date 67% of Pts had achieved CR/PR, 9% SD, 5% PD and 19% UNK. PTK/ZK exposure at steady state was similar in cycle 1 and 2. PTK/ZK had no impact on the systemic exposure of carboplatin. Paclitaxel exposure was decreased by an average of 18% in cycle 2 compared to cycle 1 for Pts treated with PTK/ZK 1250 mg/day. Conclusion: Combination of PTK/ZK with paclitaxel and carboplatin is feasible and shows favorable safety profile. The combination is active in EOC and deserves further evaluation.

[Table: see text]

A phase II, open-label study of PTK787/ZK222584 in the treatment of metastatic gastrointestinal stromal tumors (GISTs) resistant to imatinib mesylate

9531

Background: PTK787/ZK222584 (PTK/ZK) is a novel, oral selective inhibitor of certain receptor tyrosine kinases that may be important in the molecular pathogenesis of GIST (KIT, PDGFRs, VEGFR-1 and VEGFR-2). The efficacy and safety of PTK/ZK are not known in the treatment of imatinib resistant GIST. Methods: Pts who had histologically diagnosed, metastatic GIST that had progressed after at least 4 weeks of treatment with imatinib were eligible. Prior therapy with KDR inhibitor therapy was not allowed. PTK/ZK was administered orally 1,250 mg once daily until treatment failure. No concomitant systemic cancer treatments were allowed. Treatment response was monitored at 4 to 8 wk intervals and evaluated using the RECIST criteria. Adverse events (AE) were scored using the NCI/NIH Common Toxicity Criteria v. 2.0. A total of 15 pts were planned to be accrued as a 2-stage procedure. The highest prior imatinib dose: 400 mg, n=1; 600 mg, n=2; 800 mg, n=11; 1,000 mg, n=1. Prior response to imatinib: PR, n=8; SD, n=5; PD, n=1; unknown, n=1. Results: All 15 pts (M 12, F 3) enrolled were eligible. Two (13%) pts achieved PR, 8 (53%) had SD for 3 months or longer, and 5 progressed. The clinical benefit rate (PR+SD) was 67% (95% CI, 38% to 86%). The duration of the 2 PRs was 95 + and 225+ days and 8 SDs from 93+ to 346+ days. All PRs and SDs are ongoing to date. The median time to treatment failure (TTTF) has not been reached. PTK/ZK was well tolerated. The most frequently recorded AEs were dizziness (n=6), nausea/vomiting (n=6), abdominal pain/abdominal pain upper (n=4) and asthenia (n=4). All recorded AEs were either of grade 1 or 2 except for 2 events (grade 4 hypercalcemia, n=1; grade 4 pain, n=1). Conclusions: PTK787/ZK222584 showed signs of activity in this series of GIST patients who progressed during imatinib treatment. The dose of 1,250 mg o.d. is generally well tolerated.

[Table: see text]

A meta-analysis of two randomized, double-blind, placebo-controlled, phase III studies in patients (pts) with metastatic colorectal cancer (mCRC) receiving FOLFOX4 and PTK/ZK to determine clinical benefit on progression-free survival (PFS) in high LDH pts

3529

Background: PTK/ZK is an oral, antiangiogenic inhibitor of tyrosine kinase signaling of all known vascular endothelial growth factor receptors (VEGFR). PTK/ZK in combination with FOLFOX4 has been investigated in first line (CONFIRM 1[C1]) and second line (CONFIRM 2 [C2]) mCRC pts. Methods: In both trials, pts were randomized to receive PTK/ZK or placebo. Since high LDH and poor performance status (PS) have been shown to indicate poor prognosis in mCRC, pts were stratified by baseline serum LDH (≤ or > 1.5 X ULN) and PS (0, 1–2), yielding 4 strata per trial. Exploratory analysis of the high LDH strata in C1 indicated that these pts may derive the most benefit from PTK/ZK treatment. The purpose of this pre-planned meta-analysis of C1 and C2 is to determine whether the treatment effect of C1 and C2 are consistent. Results: Both trials showed strikingly similar results. High LDH pts comprise approximately 30% of the total pt population. PTK/ZK seems to have the same strong effect on PFS in high LDH pts in both 1st and 2nd line mCRC with a HR for PFS of 0.67 (p =0.010) for C1 and 0.63 (p < 0.001) for C2 (N=250 and N=316, respectively). The safety profile of PTK/ZK was highly consistent. The most frequent grade 3/4 AEs attributable to PTK/ZK were hypertension, diarrhea, fatigue, nausea, vomiting and dizziness. Increases in AEs associated with antiangiogenic therapy such as bowel perforations and bleeding complications were not observed in the PTK/ZK arms of both trials. In the meta-analysis, PTK/ZK effect on PFS is moderate in the overall population (HR 0.85, p-value 0.005). In contrast, the effect on PFS is strong and clinically meaningful in the high LDH population (HR 0.65, p-value < 0.001, N=566). Conclusion: This meta-analysis is the largest study of poor prognosis pts with high serum LDH in metastatic colorectal cancer. These data suggest that PTK/ZK significantly improves PFS in high LDH pts. Further evaluation of PTK/ZK in this pt population is planned.

[Table: see text]

Results of an interim analysis of a multinational randomized, double-blind, phase III study in patients (pts) with previously treated metastatic colorectal cancer (mCRC) receiving FOLFOX4 and PTK787/ZK 222584 (PTK/ZK) or placebo (CONFIRM 2)

3508

Background: PTK/ZK is a novel, oral, small molecule, antiangiogenic compound that inhibits tyrosine kinase signaling of all known vascular endothelial growth factor (VEGF) receptors. Methods: 855 pts were randomized to FOLFOX4 plus PTK/ZK (1250 mg, qd), or placebo. Eligibility included histologically or cytologically documented mCRC, pretreatment for metastatic disease with irinotecan/fluoropyrimidine-based chemotherapy, measurable disease by RECIST, PS of 0–2 and adequate organ and bone marrow function. The primary endpoint is overall survival (OS). Secondary endpoints included OS and PFS in high LDH pts (stratifiedbybaseline serum LDH levels > 1.5 × ULN). Results: OS was 12.1 mo in the PTK/ZK arm and 11.8 mo in the placebo arm (HR: 0.94; p=0.511). A pre-planned triangular test suggested a low probability of demonstrating an improvement in OS at the final analysis (4Q 2006). The response rates (CR+PR) were 18.5% in the PTK/ZK arm, 17.5% in the placebo arm. PFS was significantly longer in the PTK/ZK arm (5.5 mo vs. 4.1 mo; HR: 0.83; p=0.026). LDH, usually a poor prognostic factor in mCRC, is predictive of the outcome in the PTK/ZK arm. Pts with high LDH showed a strong improvement in PFS when treated with PTK/ZK (5.6 mo vs. 3.8 mo; HR: 0.63; p<0.001) and an improved OS (9.6 mo vs. 7.5 mo; HR: 0.78; p=0.10). Adverse events (AE) were similar to that of the CONFIRM 1 trial (ASCO 2005). Most frequent grade 3/4 AE associated with PTK/ZK were hypertension (PTK/ZK: 21%; placebo: 5%), diarrhea (16%; 8%), fatigue (14.5%; 6.9%), nausea (11%; 5%), vomiting (9%; 5%), dizziness (9%; 1%). AEs were generally reversible. Thrombotic and embolic events of all grades occurred in 6% (PTK/ZK) vs. 1% (placebo) and 4% vs. 1%, respectively. There was no increase in bowel perforations, hematological toxicities or peripheral neuropathy in the PTK/ZK arm. Conclusions: While the primary endpoint for OS was not met, PTK/ZK improves PFS significantly in the overall population, and shows strong activity in patients with high baseline serum LDH.

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Phase 1 study of PTK787/ZK 222584, a small molecule tyrosine kinase receptor inhibitor, for the treatment of acute myeloid leukemia and myelodysplastic syndrome

PTK787/ZK 222584 (PTK/ZK) is an oral angiogenesis inhibitor targeting vascular endothelial growth factor (VEGF) receptor tyrosine kinases, including VEGFR-1/Flt-1, VEGFR-2/KDR, VEGFR-3/Flt-4, the platelet-derived growth factor receptor tyrosine kinase and the c-kit protein tyrosine kinase. The objective of this Phase I study was to evaluate the safety, tolerability, biologic activity and pharmacologic profile of PTK/ZK administered orally, twice daily, on a continuous dosing schedule in patients with primary refractory or relapsed acute myeloid leukemia (AML), secondary AML, poor-prognosis de novo AML or advanced myelodysplastic syndrome (MDS). Acute myeloid leukemia patients for whom PTK/ZK monotherapy was ineffective could receive PTK/ZK combined with standard induction chemotherapy. Sixty-three patients received PTK/ZK at doses of 500-1000 mg orally b.i.d. Safety and pharmacokinetic data were collected. Responses were evaluated according to standard bone marrow and peripheral blood criteria. At 1000 mg b.i.d., dose-limiting toxicities of lethargy, hypertension, nausea, emesis and anorexia were observed. Other adverse events related to PTK/ZK were dizziness, weakness, fatigue, diarrhea and pruritus; these were generally mild and reversible. Pharmacokinetic data showed that steady state was reached by day 14, there was no accumulation with repeat dosing and there was no significant increase in exposure at steady state beyond the maximum tolerated dose (MTD). Complete remission was observed in five of 17 AML patients treated with PTK/ZK combined with chemotherapy. In conclusion, the MTD of PTK/ZK is 750 mg orally b.i.d. The drug is generally well tolerated and can be given in combination with chemotherapy for patients with MDS and AML.

Sedation with target-controlled propofol infusion during shoulder surgery under interscalene brachial plexus block in the sitting position

BACKGROUND AND OBJECTIVE

The aim of this study was to assess target-controlled propofol infusion as a technique of sedation for shoulder surgery under interscalene brachial plexus block in the sitting position and to evaluate the effect of sedation on hypotensive/bradycardic events during this procedure.

METHODS

One hundred and forty patients undergoing elective shoulder surgery in the sitting position under interscalene brachial plexus block (with 30 mL of ropivacaine 0.75%) were prospectively enrolled. All patients were premedicated with hydroxyzine 1 mg kg(-1), none received beta-blockers. No patients were given atropine except for the patients who experienced a vasovagal event either during the block procedure or intravenous catheter placement. The target-controlled propofol infusion was started immediately after positioning the patient on the operating table. The initial target concentration was 1 microg mL(-1). The infusion rate was adjusted every 15 min by increasing or decreasing the target concentration by 0.2 microg mL(-1) steps to maintain the patient rousable to verbal commands (score of 3 on Wilson sedation scale). The following parameters were assessed: minimal, maximal, optimal target concentration, respiratory and haemodynamic parameters, total propofol dose, additional alfentanil needs, occurrence of hypotensive/bradycardic events, complications. Results are mean +/- SD. Statistical analysis used t-test and chi2-tests.

RESULTS

The optimal propofol target concentration was 0.8 mug mL(-1). No respiratory complications or conversion to general anaesthesia was reported. Two patients experienced transient and inconsequential intraoperative agitation. The incidence of hypotensive/bradycardic events during the procedure was 5.7% (eight patients).

CONCLUSION

Target-controlled propofol infusion (0.8-0.9 microg mL(-1)) following hydroxyzine premedication is a safe and effective technique for sedation when combined with interscalene brachial plexus block during shoulder surgery in the sitting position.