Sunitinib as second-line treatment for advanced gastric cancer: preliminary results from a phase II study

Abstract

4603 Background: Sunitinib malate (SU) is an oral, multitargeted tyrosine kinase inhibitor of VEGFRs, PDGFRs, KIT, RET, and FLT3, approved internationally for the treatment of advanced RCC and imatinib-resistant or -intolerant GIST. We investigated the safety and activity of SU monotherapy in pts with previously-treated gastric cancer. Preliminary results from this open-label, multicenter, phase II study are reported. Methods: Eligibility criteria included measurable stage IV disease; 1 prior chemotherapy regimen; and ECOG PS =1. Pts took SU 50 mg/day for 4 wks followed by 2 wks off treatment in 6-wk cycles. A Simon 2-stage design was used with a target accrual of 38 pts in the first stage, expanding to 63 pts if =2 partial responses (PRs) were observed. The primary endpoint was RECIST-defined objective response rate. Secondary endpoints included duration of response and safety. Pharmacokinetic (PK) Ctrough parameters were also monitored. Results: As of Sept 15 2006, 38 evaluable pts (median age 56 years [range 29–78]; 2–3 metastatic sites [63%]; prior treatment with 5-FU ± platinum [P] [24%], capecitabine ± P [13%], TS-1 ± P [26%], other [37%]) have received a median of 2 SU cycles (range 1–3). Of 21 pts evaluable for efficacy, 1 PR has been confirmed and 8 pts had stable disease (SD), 4 with SD for =2 cycles. The most commonly reported AEs were typically grade 1/2 in severity and included stomatitis, skin discoloration, fatigue, anorexia, diarrhea, hand-foot syndrome (HFS), nausea and vomiting. Grade 3/4 toxicities included HFS (10.5%), fatigue (7.9%), anorexia (7.9%) and mucosal inflammation (5.3%). Grade 3/4 hematologic toxicities included neutropenia (29%), thrombocytopenia (29%) and anemia (11%). 7 pts experienced serious SU- related AEs requiring dose modifications in 3 pts and treatment discontinuation in 1 pt. Preliminary PK investigations indicate that concentrations seen in gastric pts are similar to those seen in other pts treated with SU. Conclusions: These initial findings show that SU is generally well tolerated and may have single-agent antitumor activity in pre-treated gastric cancer pts. Further trials with SU in combination with standard chemotherapy regimens are planned. No significant financial relationships to disclose.