Clinical activity of imatinib mesylate in combination with docetaxel in patients with advanced, platinum-resistant ovarian cancer—Hoosier Oncology Group GYN03–62

Abstract

5091 Background: Ovarian tumors harborc-Kit and PDGF receptors. We showed in an in-vitro model that Imatinib (G) inhibits the growth of ovarian cancer cells. We hypothesized that G in combination with chemotherapy inhibits the growth of ovarian tumors. Data from a phase II clinical trial utilizing G in combination with Docetaxel (D) in patients with advanced ovarian cancer (OC) are presented. Methods: This was an open label, one stage, multi-center phase II clinical trial. Planned sample size was 23. Patients with relapsed, platinum-resistant or refractory OC expressing PDGFR or c-kit were eligible. PDGFR and c-kit expression was assessed prior to enrollment by IHC using archival tumor tissue. G was administered at 600mg/d continuously and D was given weekly (30mg/m2) for 4 weeks, with 2 weeks break. Each cycle was 6 weeks, with a maximum of 6 cycles allowed. Tumor assessments were obtained after 2, 4 and 6 cycles. Response rate by RECIST was the primary endpoint. Results: 34 patients were screened. 17 tumors were c-kit + and 25 were PDGFRα +. 23 patients were enrolled. Of those, 4 patients had c-kit+/PDGFR- tumors, 12 were PDGFR+/c-kit- and 7 were c-kit+/PDGFR+. Median age was 55 (range 33–76) and median PS was 0 (range 0–2). Median number of prior treatments was 3 (range 1–9). Efficacy and toxicity data are available for 20 and 14 patients, respectively. Based on RECIST, there were 3 patients with PR and 3 patients with SD lasting at least 12 weeks. Of these 6 patients, 2 pts were c-kit+, 2 were PDGFR+ and 2 were PDGFR and c-kit+. All 6 patients had carboplatin and taxane resistant disease. Grade 3–4 toxicities were: neutropenia (2), thrombocytopenia (1), fatigue (1), dehydration (1), constipation (1), cardiac ischemia (1), nausea/vomiting (2), urinary frequency (1). Other G1–2 toxicities were: N/V (9), diarrhea (7), fatigue (8), mucositis (4), anemia (4), hypocalcemia (5), rash (6), anorexia (7), edema (5), hemolysis (1), non-neutropenic infections (7). Additional data will be available in May 2006. Conclusions: The combination G+D is tolerated well. Clinical activity consisted of 3 PRs (15% response rate) and 3 SD > 3 months in pts with heavily pre-treated, platinum resistant OC expressing c-kit or PDGFRα. [Table: see text]