A significant subset of non-small cell lung cancer (NSCLC) patients have mutations in the EGFR gene; many of these patients benefit from drugs that block EGFR. A phase I clinical trial of CetuGEX, an antibody (a type of immune system protein) against EGFR, examined 41 patients with different types of advanced cancer, including some with NSCLC, who had mutations in the EGFR gene and whose cancer had progressed after standard treatment. The treatment was relatively well tolerated. One patient with NSCLC went into complete remission, while three patients with other cancers had partial responses. Fifteen more patients had stable disease, that is, their cancer did not grow during treatment. All treatment responders are still being treated with CetuGEX, with the longest response lasting over 18 months, so far.