Integrating novel agents into the curative treatment of head and neck cancer

A phase I clinical study of VB4-845: weekly intratumoral administration of an anti-EpCAM recombinant fusion protein in patients with squamous cell carcinoma of the head and neck

VB4-845 is a scFv-Pseudomonas exotoxin A fusion construct that targets epithelial cell adhesion molecule (EpCAM). A phase I trial was conducted to determine the maximum tolerated dose (MTD) of VB4-845 when administered as weekly intratumoral (IT) injections to patients with squamous cell carcinoma of the head and neck (SCCHN). Secondary objectives included the evaluation of the safety, tolerability, pharmacokinetic profile, and immunogenicity, and a preliminary assessment of tumor response. Twenty patients with advanced, recurrent SCCHN were treated weekly for four weeks in ascending dose cohorts of 100, 200, 330, 500, 700, and 930 microg. The MTD was established as 930 microg with a dose limiting toxicity of elevated liver enzymes in two of five patients. VB4-845 therapy was well tolerated with common treatment-related adverse events of injection site reactions, fever, gastrointestinal disorders, and elevated liver enzyme levels. All patients developed antibodies to VB4-845 by the end of the study, but only seven patients had neutralizing antibodies. Preliminary efficacy data found 87.5% of EpCAM-positive patients had a positive response to VB4-845 therapy. Noninjected dermal metastases were also resolved in one patient. VB4-845 IT therapy is safe and feasible and warrants further clinical evaluation for the treatment of SCCHN.

Enhancement of docetaxel-induced cytotoxicity by blocking epidermal growth factor receptor and cyclooxygenase-2 pathways in squamous cell carcinoma of the head and neck

PURPOSE

The addition of molecular targeted agents to enhance the cytotoxicity of chemotherapeutic agents is a promising strategy in cancer treatment. The combination of cyclooxygenase-2 inhibitors and epidermal growth factor receptor tyrosine kinase inhibitors, such as celecoxib and ZD1839 (gefitinib), was reported to achieve synergistic cell growth inhibition in squamous cell carcinoma of the head and neck. Therefore, we postulated that the addition of celecoxib and ZD1839 to docetaxel, a cytotoxic agent, might further increase antitumor activity.

EXPERIMENTAL DESIGN

The combination of celecoxib, ZD1839, and docetaxel was studied for its effect on cell growth and apoptosis by cell growth inhibition and Annexin V assays. The relevant molecular targets of these agents and apoptotic markers were examined by immunoblotting analyses in the presence or absence of these three drugs. Morphologic changes of the microtubule cytoskeleton, a known target of docetaxel, were also evaluated by staining for alpha-tubulin after the combination treatment.

RESULTS

We showed that this triple combination significantly enhanced cell growth inhibition and docetaxel-induced apoptosis. Docetaxel mainly induced caspase-8 activation, whereas the addition of celecoxib and ZD1839 augmented the caspase-8 activation and enhanced caspase-9 activation. One of the underlying mechanisms for augmentation of docetaxel-induced apoptosis by celecoxib and ZD1839 is to further inhibit the activation of prosurvival pathway molecules, such as extracellular signal-regulated kinase and AKT, and the promotion of aberrant apoptosis.

CONCLUSIONS

Our studies suggest that the combination of docetaxel with a cyclooxygenase-2 inhibitor and an epidermal growth factor receptor tyrosine kinase inhibitor may further improve efficacy of docetaxel and other taxane-based therapies in squamous cell carcinoma of the head and neck.