Phase II clinical trial of S-1 plus nanoparticle albumin-bound paclitaxel in untreated patients with metastatic gastric cancer

Abstract

The present study is the first phase II clinical trial aimed to evaluate the efficacy and safety of S-1 plus nanoparticle albumin-bound paclitaxel (Nab-PTX) as first-line chemotherapy for advanced gastric cancer (AGC). Previously untreated patients with metastatic gastric adenocarcinoma received S-1 in oral doses of 40 mg (BSA <1.25 m² ), 50 mg (1.25 ≤ BSA < 1.50 m² ) and 60 mg (BSA ≥1.50 m² ) b.i.d. on days 1-14 in combination with Nab-PTX (120 mg/m² , on days 1 and 8) for each 21-day cycle. Primary endpoint was progression-free survival (PFS), and secondary endpoints were overall response rate (ORR), overall survival (OS), disease control rate (DCR), and toxicity. A total of 73 gastric cancer patients with metastatic and measurable lesions were enrolled in the first-line setting. Median PFS and OS were 9.63 months and 14.60 months, respectively. Four (5.5%) patients had complete responses, 39 (53.4%) had partial responses (PRs), 21 (28.8%) had stable disease, four (5.5%) progressed and five (6.8%) were not evaluable. ORR and DCR were 58.9% and 87.7%, respectively. Most toxicities were mild, and no treatment-related deaths occurred. Grade 3 to 4 toxicities occurred in 22 patients (30.1%) as follows: leukopenia (13.7%), neutropenia (12.3%), anemia (5.5%), thrombocytopenia (1.4%), diarrhea (6.8%), vomiting (2.7%), stomatitis (1.4%), peripheral neuropathy (1.4%), and hand-foot syndrome (1.4%). Seven patients achieved good responses and underwent gastrectomy plus metastasectomy. Thirty (41.1%) patients had S-1 maintenance with a median of four cycles. S-1 plus Nab-PTX is an efficient and safe regimen as first-line treatment for patients with AGC.

Keywords: S-1; advanced gastric cancer; chemotherapy; first-line; nanoparticle albumin-bound paclitaxel.