A phase I dose escalation and pharmacokinetic study of vatalanib (PTK787/ZK 222584) in combination with paclitaxel in patients with advanced solid tumors

Phase I, Pharmacogenomic, Drug Interaction Study of Sorafenib and Bevacizumab in Combination with Paclitaxel in Patients with Advanced Refractory Solid Tumors

VEGF blockade does not uniformly result in clinical benefit. We evaluated safety, dose-limiting toxicities (DLT), recommended phase II dose (RP2D), antitumor efficacy, and exploratory biomarkers including pharmacogenomics and pharmacokinetics with sorafenib, bevacizumab, and paclitaxel in patients with refractory cancers. The study had a "3 + 3" design, using paclitaxel 80 mg/m² every week for 3 weeks, in every 4 week cycles, bevacizumab 5 mg/kg every 2 weeks, and sorafenib 200 or 400 mg twice a day, 5 or 7 days/week (5/7, 7/7). The MTD cohort was expanded. Twenty-seven patients enrolled in 3 cohorts: sorafenib 200 mg twice a day 5/7, 200 mg twice a day 7/7, and 400 mg twice a day 5/7. DLTs were grade 3 neutropenia >7 days (cohort 1, 1), grade 3 hypertension (cohort 2, 1), grade 3 hand-foot skin reaction (HFSR; cohort 3, 2). MTD was sorafenib 200 mg twice a day 7/7. Six DLTs occurred in cohort 2 expansion: grade 3 HFSR (2), grade 2 HFSR with sorafenib delay >7 days (2), grade 4 cerebrovascular accident (1), grade 3 neutropenia >7 days (1). RP2D was sorafenib 200 mg twice a day 5/7. Most patients (62%) dose reduced sorafenib to 200 mg daily 5/7 after a median 3 (range, 2-17) cycles. Response rates were 48% overall (27) and 64% for ovarian cancers (14). VEGF-A-1154AA and -7TT recessive homozygous genotypes conferred worse overall survival versus alternative genotypes (7 vs. 22 months). Intermittent, low-dose sorafenib (200 mg twice a day 5/7) combined with bevacizumab and paclitaxel was tolerable and had high antitumor efficacy in patients with refractory cancer (NCT00572078).

A phase I study of the vascular endothelial growth factor inhibitor Vatalanib in combination with Pemetrexed disodium in patients with advanced solid tumors

Introduction Vatalanib is an oral receptor tyrosine kinase inhibitor that blocks all known VEGF, PDGF, and c-Kit receptors. This phase I study evaluated the safety, tolerability, and biologic activity of the combination of vatalanib with pemetrexed disodium in patients with advanced solid tumors. Methods Patients were administered escalating twice daily doses of vatalanib in combination with pemetrexed disodium in 21-day cycles. A dose expansion cohort was enrolled to further define the maximum tolerated dose (MTD) and further evaluate efficacy. Results A total of 29 patients were enrolled in the study (dose escalation, 9; dose expansion, 20). Dose-limiting toxicities included grade 4 thrombocytopenia (6.9%) and febrile neutropenia, anorexia, constipation, and dehydration. Other common adverse events were fatigue (75%), nausea (66%), vomiting (48%), oral mucositis (31%) and diarrhea (28%). The majority of these toxicities were Grade 1-2. The MTD was reached at vatalanib 250 mg twice daily continuously combined with pemetrexed disodium 500 mg/m² day 1. Overall, 2 patients (6.9%) had partial responses, 8 (27.6%) had stable disease for at least 4 cycles, 5 had progressive disease (17.2%) and 5 went off study before disease assessment. Conclusion The combination of vatalanib with pemetrexed disodium was feasible, but not well tolerated. The modest efficacy results are consistent with other results obtained from combinations of chemotherapy and a large number of VEGF tyrosine kinase inhibitors. This combination should not be developed further unless predictive biomarkers can be identified.

Pharmacokinetic Aspects of Vascular Endothelial Growth Factor Tyrosine Kinase Inhibitors

Scientists have identified the impact of angiogenesis on tumor growth and survival. Among other efficient drugs, several small-molecule tyrosine kinase inhibitors (TKIs) targeting the vascular endothelial growth factor receptor (VEGFR) have been developed and have already been integrated into the treatment of various advanced malignancies. This review provides a compilation of current knowledge on the pharmacokinetic aspects of all VEGFR-TKIs already approved by the US Food and Drug Administration (FDA) and the European Medicines Agency (EMA) and of those still under investigation. Additional information on substance metabolism, potential for drug-drug interactions (DDIs), and the need for dose adaptation in patients with predominant renal and/or hepatic impairment has been included. All TKIs introduced in this review were administered orally, allowing for easy drug handling for healthcare professionals and patients. For almost all substances, the maximum plasma concentrations were reached within a short period of time. The majority of the substances showed a high plasma protein binding and their excretion occurred via the feces and, to a lesser extent, via the urine. In most cases, dose adaptation in patients with mild to moderate renal or hepatic impairment is not recommended. Cytochrome P450 (CYP) 3A4 was found to play a crucial role in the drug metabolic processes of many compounds. In order to prevent unwanted DDIs, co-administration of VEGFR TKIs together with CYP3A4 inhibitors or inducers should be avoided. Throughout all TKIs, the data indicate high inter-individual variability. The causes of this are still unclear and require further research to allow for individualization of treatment regimens.

Targeting angiogenesis in metastatic breast cancer

Angiogenesis has become an important target in the treatment of several solid tumors, including breast cancer. As monotherapy, antiangiogenic agents have demonstrated limited activity in metastatic breast cancer (MBC); therefore, they have generally been developed for use in combination with chemotherapies. Thus far, the experience with antiangiogenic agents for MBC has been mixed. The results from one study assessing addition of the monoclonal antibody bevacizumab to paclitaxel led to approval of bevacizumab for MBC. However, the modest improvement of progression-free survival rates in subsequent MBC studies has led to reappraisal of bevacizumab. Phase III studies have not produced evidence supporting use of the multikinase inhibitor sunitinib alone or in combination with MBC chemotherapy. Experience with sorafenib in a phase IIb program indicates potential when used in select combinations, particularly with capecitabine; however, phase III confirmatory data are needed. Although antiangiogenic therapies combined with chemotherapy have increased progression-free survival rates for patients with MBC, increases in overall survival times have not been observed. Some studies have tried to combine antiangiogenic agents such as bevacizumab and sunitinib or sorafenib, but that approach has been limited because of toxicity concerns. Sequential use of antiangiogenic agents with differing mechanisms of action may be an effective approach. Despite setbacks, angiogenesis will likely remain an important target of treatment for selected patients with MBC.