Combining bevacizumab and chemoradiation in rectal cancer. Translational results of the AXEBeam trial.

BACKGROUND: This study characterises molecular effect of bevacizumab, and explores the relation of molecular and genetic markers with response to bevacizumab combined with chemoradiotherapy (CRT). METHODS: From a subset of 59 patients of 84 rectal cancer patients included in a phase II study combining bevacizumab with CRT, tumour and blood samples were collected before and during treatment, offering the possibility to evaluate changes induced by one dose of bevacizumab. We performed cDNA microarrays, stains for CD31/CD34 combined with α-SMA and CA-IX, as well as enzyme-linked immunosorbent assay (ELISA) for circulating angiogenic proteins. Markers were related with the pathological response of patients. RESULTS: One dose of bevacizumab changed the expression of 14 genes and led to a significant decrease in microvessel density and in the proportion of pericyte-covered blood vessels, and a small but nonsignificant increase in hypoxia. Alterations in angiogenic processes after bevacizumab delivery were only detected in responding tumours. Lower PDGFA expression and PDGF-BB levels, less pericyte-covered blood vessels and higher CA-IX expression were found after bevacizumab treatment only in patients with pathological complete response. CONCLUSIONS: We could not support the 'normalization hypothesis' and suggest a role for PDGFA, PDGF-BB, CA-IX and α-SMA. Validation in larger patient groups is needed.

Phase I study of Aplidine in a dailyx5 one-hour infusion every 3 weeks in patients with solid tumors refractory to standard therapy. A National Cancer Institute of Canada Clinical Trials Group study: NCIC CTG IND 115.

BACKGROUND: Aplidine is a cyclic depsipeptide isolated from the marine tunicate Aplidium albicans. METHODS: This phase I study of Aplidine given as a 1-hour i.v. infusion daily for 5 days every 3 weeks was conducted in patients with refractory solid tumors. Objectives were to define the dose limiting toxicities, the maximal tolerated dose, and the recommended phase II dose. RESULTS: Thirty-seven patients were accrued on study. Doses ranged from 80 microg/m(2) to 1500 microg/m(2)/day. Eleven patients received more than three cycles of Aplidine. Dose-limiting toxicities occurred at 1500 microg/m(2) and 1350 microg/m(2)/day and consisted of nausea, vomiting, myalgia, fatigue, skin rash and diarrhea. Mild to moderate muscular pain and weakness was noted in patients treated with multiple cycles with no significant drug related neurotoxicity. Bone marrow toxicity was not observed. The recommended dose for phase II studies was 1200 microg/m(2) daily for 5 days, every 3 weeks. Pharmacokinetic studies performed during the first cycle demonstrated that therapeutic plasma levels of Aplidine are reachable well below the recommended dose. Nine patients with progressive disease at study entry had stable disease and two had minor responses, one in non-small cell lung cancer and one in colorectal cancer. CONCLUSIONS: Aplidine given at a dose of 1200 microg/m(2) daily for 5 days, every 3 weeks is well tolerated with few severe adverse events. This schedule of Aplidine is under evaluation in phase II studies in hematological malignancies and solid tumors.

A National Cancer Institute of Canada Clinical Trials Group Study--IND.135: Phase I/II study of irinotecan (camptosar), oxaliplatin and raltitrexed (tomudex) (COT) in patients with advanced colorectal cancer.

Thirty-one patients with metastatic colorectal cancer were enrolled in this phase I/II trial of a triple combination of camptosar (C), oxaliplatin (O) and tomudex (T), all given on day one of a convenient three-week schedule. Patients received 257 cycles (1-18) in five cohorts. Toxicity was manageable and haematological toxicity was mild to moderate. Diarrhoea was the main dose-limiting toxicity; nausea and vomiting were common. Fatigue was frequent, moderate in severity and a reason for discontinuation in some patients. The recommended phase II doses were (C) 220 mg/m(2), (O) 100mg/m(2), (T) 2.75 mg/m(2). A 50% response rate in 30 evaluable patients was confirmed by an independent radiology review board; progression-free survival and overall median survival were 7.3 months and 16.6 months, respectively. Of the 16 patients treated at the recommended dose, 9 (56.3%) experienced partial response. Further evaluation in a randomized study compared to sequential doublets is warranted. Triple combinations could be relevant in curative settings for high-risk patients.