Phase I Study of a Statin + Erlotinib for Advanced Solid Malignancies With Focus on Squamous Cell Carcinomas and NSCLC

Cytotoxic chemotherapy remains the mainstay of anti-cancer medical treatment for the vast majority of patients with locally advanced or metastatic squamous cell cancers. However, curative success remains low and most patients eventually succumb to the disease or its complications. Moreover, cytotoxic chemotherapy is frequently associated with severe unwanted side effects. Therefore, in this patient population the unmet therapeutic need is high and new treatment is required. Statins are drugs which inhibit the cellular mevalonate pathway and are conventionally used in the treatment of hypercholesterolemia in cardiovascular disorders. Increasing evidence suggests that statins might be used for cancer prevention/treatment through their interactions with essential cellular functions, such as cell proliferation and differentiation. Recent in vitro data indicate that statins induce growth arrest and apoptosis, inhibit secretion of proteolytic enzymes, reduce invasiveness and inhibit angiogenesis. These effects contribute to the reduction of tumor growth and metastases in preclinical in vivo models of a variety of tumors suggesting that statins may be useful in anticancer therapy. Studies previously performed by our group demonstrated that targeting the mevalonate pathway can induce tumor specific cytotoxicity in a number of tumor types that included squamous cell carcinomas, myeloid leukemia and a variety of pediatric cancers. Additionally, several clinical trials have also assessed the antitumor activity of statins. Pre-clinically, we have demonstrated additive cytotoxic effects when combining lovastatin with tyrosine kinase inhibitors of the Epidermal Growth Factor Receptor (EGFR) in HNSCC cells (AG1478) and in 8 squamous cell carcinomas (gefitinib). Mechanistically, lovastatin treatment inhibited EGF induced EGFR autophosphorylation by 24hrs and showed co-operative targeting of the EGFR in combination with gefitinib. Taken together, these results demonstrate that targeting the mevalonate pathway can inhibit EGFR function and suggest the potential utility of combining these classes of drugs (i.e. an EGFR tyrosine kinase inhibitor and a statin). The use of lovastatin is not optimal due to greatly enhanced toxicity with drugs such as gefitinib and erlotinib that are simultaneously metabolized by the same enzyme (cytP450A4). In contrast, rosuvastatin a relatively novel potent mevalonate pathway inhibitor is not metabolized significantly by cytP450A4. Due to the enhanced clinical activity of erlotinib in comparison to other EGFR tyrosine kinase inhibitors, the combination of erlotinib and rosuvastatin appears ideal.