Gefitinib in second line treatment of metastatic or locally advanced synovial sarcoma expressing HER1: A phase II trial of EORTC Soft Tissue and Bone Sarcoma Group.

9517 Background: Synovial sarcomas (SyS) have been reported to overexpress HER1 in gene expression profile experiments and immunohistochemistry. Gefitinib, a specific inhibitor of HER1, was therefore tested in advanced or metastatic SyS failing doxorubicin (Doxo) ± ifosfamide (Ifo). METHODS Patients (pts) with advanced or metastatic SyS expressing HER1 using IHC were included. The principal inclusion criterias were: disease not curable with surgery and/or radiation, presence of a measurable progressive lesion(s), pretreatment with 1-3 line of chemotherapy in metastatic phase, ECOG PS 0 to 2, age ≥18 years. Gefitinib was given at 500mg/day until progression or intolerance. Primary endpoint was the rate of progression free survival at 3 months. A two step Simon design was used with a p0 of 25% and a p1 of 45%, with α and β of 0.1. 44 patients were scheduled to be recruited. RESULTS Between 10/02 and 10/05, 48 pts were included in 12 EORTC STBSG centers, 27 (56%) males and 21 (44%) females. Median age was 42 years (range 19-66). Metastatic sites were lung in 92% and soft tissue or lymph nodes in 42%, of the patients. Respectively 42, 40 and 18% of the patients had received 1, 2 and >2 lines of CT. As of December 2005, 37 pts are evaluable for toxicity and 39 for the primary endpoint. Median treatment duration was 11 weeks (range 2-25). Toxicity (G1-4) reported included fatigue (43%), diarrhea (54%), cough (35%), dyspnea (43%), cutaneous (73%). G3-4 toxicities were dyspnea (9), fatigue (4), cutaneous (2), cough (1), neurological (2), thombosis (2), hypoxia (1), infection (1). There was no drug related death. No dose reduction has been reported so far, but treatment had to be temporarily interrupted in 23% of the patients. As of December 2005, there were no objective response reported. Seven (18%) pts achieved stable disease as best response. At 3 months, 5 of the 39 (13%) evaluable patients achieved PFS; 6 and 12 months PFS were 10% and 3% respectively. CONCLUSIONS 13% of SyS expressing HER1 achieved prolonged progression free survival at least 12 weeks) with gefitinib. Gene expression profiling and protein expression were not accurate predictors of gefitinib activity in this model. No significant financial relationships to disclose.