A phase 3 study published in the Journal of Clinical Oncology reveals that the SOXRC regimen—a combination of camrelizumab, rivoceranib, and chemotherapy (S-1 and oxaliplatin)—elicits superior responses compared to chemotherapy alone (SOX) in patients with locally advanced gastric or gastroesophageal junction (G/GEJ) adenocarcinoma. The DRAGON IV/CAP 05 study assessed the efficacy of this combined approach in the perioperative setting.
Improved Pathologic Response with SOXRC
The study involved 180 patients divided into SOXRC and SOX groups. Results indicated a significant improvement in pathologic complete response rates with SOXRC, achieving 18.3% compared to 5% with SOX alone. Major pathologic response rates also favored SOXRC, with 51.1% versus 37.8% in the SOX group. These findings suggest that the addition of camrelizumab and rivoceranib to standard chemotherapy enhances the treatment's effectiveness in reducing or eliminating cancer cells.
The trial initially included a third arm (SOXR) involving high-dose rivoceranib, but it was discontinued due to safety concerns observed in the first 103 patients. The published results focus on the comparison between SOXRC and SOX in the first 360 patients eligible for surgery.
Treatment Protocol and Side Effects
Patients received three cycles of presurgical therapy, followed by radical gastrectomy, and then three cycles of postsurgical therapy. The SOXRC group received additional cycles of camrelizumab and rivoceranib, while the SOXR group received additional rivoceranib. Treatment could continue for up to one year for rivoceranib and up to 17 doses of camrelizumab. In the SOX group, continuation of S-1 was at the researchers' discretion.
Treatment-related side effects of any grade were more common in the SOXRC group (88%) compared to the SOX group (80%). Grade 3 or higher side effects occurred in 34% and 17% of patients, respectively. These side effects led to dose interruptions, delays, or reductions in 41% of SOXRC patients and 26% of SOX patients. The most frequent side effects included decreased neutrophil count, decreased white blood cell count, and decreased platelet count.
Expert Commentary
Dr. Andrew H. Ko, associate editor of the Journal of Clinical Oncology, noted that while combined PD-1/VEGFR inhibition plus chemotherapy is not yet ready for routine use, the study provides an encouraging early signal of efficacy. He emphasized the need for longer-term data focused on oncologic outcomes to determine if this enhanced strategy can be adopted into clinical practice.
