Phase II trial of bevacizumab and sorafenib in recurrent ovarian cancer patients with or without prior-bevacizumab treatment.

OBJECTIVE: To examine whether blocking multiple points of the angiogenesis pathway by addition of sorafenib, a multi-kinase inhibitor against VEGFR2/3, Raf, c-Kit, and PDGFR, to bevacizumab would yield clinical activity in ovarian cancer (OvCa). METHODS: This phase II study tested bevacizumab plus sorafenib in two cohorts; bevacizumab-naïve and bevacizumab-exposed patients. Bevacizumab (5 mg/kg IV every 2 weeks) was given with sorafenib 200 mg bid 5 days-on/2 days-off. The primary objective was response rate using a Simon two-stage optimal design. Progression-free survival (PFS) and toxicity were the secondary endpoints. Exploratory correlative studies included plasma cytokine concentrations, tissue proteomics and dynamic contrast-enhanced-magnetic resonance imaging (DCE-MRI). RESULTS: Between March 2007 and August 2012, 54 women were enrolled, 41 bevacizumab-naive and 13 bevacizumab-prior, with median 5 (2-9) and 6 (5-9) prior systemic therapies, respectively. Nine of 35 (26%) evaluable bevacizumab-naive patients attained partial responses (PR), and 18 had stable disease (SD) ≥ 4 months. No responses were seen in the bevacizumab-prior group and 7 (54%) patients had SD ≥ 4 months, including one exceptional responder with SD of 27 months. The overall median PFS was 5.5 months (95%CI: 4.0-6.8 months). Treatment-related grade 3/4 adverse events (≥5%) included hypertension (17/54 [31%]; grade 3 in 16 patients and grade 4 in one patient) and venous thrombosis or pulmonary embolism (5/54 [9%]; grade 3 in 4 patients and grade 4 in one patient). Pretreatment low IL8 concentration was associated with PFS ≥ 4 months (p = .031). CONCLUSIONS: The bevacizumab and sorafenib combination did not meet the pre-specified primary endpoint although some clinical activity was seen in heavily-pretreated bevacizumab-naive OvCa patients with platinum-resistant disease. Anticipated class toxicities required close monitoring and dose modifications.

Translational predictive biomarker analysis of the phase 1b sorafenib and bevacizumab study expansion cohort.

Predictive biomarkers are needed to triage patients to the best therapy. We prospectively planned examination of sequential blood, biopsy, and functional imaging with which to confirm the mechanism and to identify potential predictive biomarkers in a phase Ib clinical trial expansion of patients with solid tumors receiving sorafenib/bevacizumab. The maximally tolerated doses of sorafenib at 200 mg twice daily with bevacizumab at 5 mg/kg every other week were given to biopsiable patients. Patients were randomized to receive either sorafenib or bevacizumab monotherapy for the first 28-day cycle with the second drug added with cycle 2. Biopsies, dynamic contrast-enhanced MRI, and fluorodeoxyglucose-proton emission tomography were done pre-therapy and at 2 and 6 weeks (2 weeks into combination therapy). Tumor and serum proteomics, Ras/Raf mutational analysis, and functional imaging results were examined individually and across the dataset to identify potential changes predictive of response to therapy and those that confirm the biochemical drug mechanism(s). Therapy with sorafenib/bevacizumab resulted in clinical benefit in 45% of this mixed solid tumor group. ERK activation and microvessel density were decreased with monotherapy treatment with sorafenib or bevacizumab, respectively; whereas a decreased signal over the group of total AKT, phospho(p)-VEGF receptor2, p-endothelial nitric-oxide synthase, b-RAF, and cleaved poly(ADP-ribose) polymerase was associated with earlier progression of disease. Tumor metabolic activity decreased in those patients with clinical benefits lasting longer than 4 months, and activity increased with progression of disease. Cleavage of caspase 3 and poly(ADP-ribose) polymerase was increased, and Ki67 expression decreased in patients with prolonged clinical benefits, consistent with decreased proliferation and increased apoptosis. The conglomerate analysis, incorporating pharmacodynamic and tumor biochemistry, demonstrated sorafenib/bevacizumab-targeted vascular activity in the tumor. Results suggest potential biomarkers for which changes, as a group, during early therapeutic exposure may predict clinical benefit.

cDNA microarray profiling of rat mammary gland carcinomas induced by 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine and 7,12-dimethylbenz[a]anthracene.

cDNA microarray analysis was used to examine gene expression profiles in normal female Sprague-Dawley rat mammary gland and in carcinomas induced by the cooked meat-derived carcinogen 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) and the potent experimental carcinogen 7,12-dimethylbenz[a]anthracene (DMBA). Nine tubulopapillary carcinomas (five from PhIP-treated rats and four from DMBA-treated rats) and normal mammary gland from virgin, pregnant and lactating rats were examined on a rat 6.9k cDNA microarray. Although histologically identical, PhIP- and DMBA-induced carcinomas could be distinguished by hierarchical clustering and multi-dimensional scaling analyses of cDNA expression. In addition, the expression of 21 clones was statistically different between PhIP- and DMBA-induced carcinomas (F-test, P < 0.05). The data indicate that distinct chemical carcinogens induce unique gene expression patterns in mammary gland carcinomas. The specific chemical carcinogen-associated cDNA array profiles found in carcinomas may ultimately be applicable to better understanding cancer etiology. PhIP- and DMBA-induced carcinomas also shared similarities in cDNA expression profiles. By comparing the expression in carcinomas (PhIP plus DMBA induced) with normal rat mammary gland (at any stage of differentiation), 172 clones were found to be differentially expressed. Genes showing increased expression in carcinomas by cDNA microarray analysis (and further validated by immunohistochemistry and western blot analysis) include cyclin D1, PDGF-A chain, retinol binding protein 1, prohibitin and the transcription factor STAT5A. The similarities in gene expression between PhIP- and DMBA-induced carcinomas raise the possibility that several molecular pathways for rat mammary gland transformation are maintained irrespective of the carcinogenic initiating agent.