Chemo agents equal in treating gastric cancer
Weekly paclitaxel was as effective as biweekly irinotecan (Camptosar) as second-line therapy for advanced gastric cancer, researchers found.
In a phase III trial comparing paclitaxel with irinotecan in patients who were refractory to treatment with fluoropyrimidine with platinum, there was no significant difference in outcomes for median overall survival (9.5 months versus 8.4 months, hazard ratio 1.13, 95% CI 0.86-1.49, P=0.38), according to Shuichi Hironaka, MD, of the Chiba Cancer Center in Japan, and colleagues.
Results were also similar for progression-free survival (P=0.33) and response rate (P=0.24) for the two agents, they wrote online in the Journal of Clinical Oncology.
Patients who received paclitaxel had a smaller proportion of grade 3 and 4 adverse events, they reported. There were two treatment-related deaths in the group receiving irinotecan.
Paclitaxel was approved to treat pancreatic cancer in combination with gemcitabine (Gemzar) in September 2013.
The authors noted that no prior research had compared the two drugs in treating advanced gastric cancer that was refractory to fluoropyrimidine plus platinum.
They conducted a prospective, open-label, parallel-group, study in 219 Japanese patients randomized to receive weekly paclitaxel (n=108) or biweekly irinotecan (n=111) to a primary endpoint of overall survival (OS), and to secondary endpoints of progression-free survival (PFS), response rate, adverse events, and the proportion of patients who required third-line chemotherapy.
Participants had to meet the following criteria:
- Histologically confirmed metastatic or recurrent gastric adenocarcinoma
- An Eastern Cooperative Oncology Group performance status of 0 to 2
- Confirmation of disease progression by CT or other imaging during or within a month following the last dose of first-line chemotherapy with fluoropyrimidine plus platinum
- No prior therapy with taxanes or irinotecan
- No severe peritoneal metastasis
Patients received 80 mg/m2 of paclitaxel on days one, eight, and 15 every 4 weeks with histamine receptor-1 and -2 blockers 30 minutes prior to drug administration for prevention of allergic reactions. The irinotecan group received 150 mg/m2 of drug of days one and 15 every 4 weeks.
Treatment was maintained until disease progression, occurrence of unacceptable serious toxicity, or patient refusal of treatment.
Paclitaxel was administered a median 11.5 times versus 4.5 times in the irinotecan group. Discontinuation was tied to disease progression in 86.7%, adverse events in 7.3%, withdrawal of consent in 3.2%, and for other reasons in 2.8%.
OS and PFS were not significantly difference between treatment groups. The PFS was a median 3.6 months for paclitaxel versus 2.3 months for irinotecan (HR 1.14, 95% CI 0.88-1.49).
The response rate was 20.9% in the paclitaxel group and 13.6% in the irinotecan group.
A third-line chemotherapy was administered to 89.8% of those receiving paclitaxel and 72.1% of those receiving irinotecan, for a significant difference (P=0.001).
Third-line chemotherapy contained irinotecan for three-fourths of the patients in the paclitaxel group. In the irinotecan group, more than half the patients received a taxane-containing regimen as third-line treatment.
Grade 3 and 4 adverse events included neutropenia (28.7% with paclitaxel versus 39.1% with irinotecan), anemia (21.3% versus 30%), and anorexia (7.4% versus 17.3%).
The causes of death for two patients in the irinotecan group were serious pneumonia and gastric perforation.
These data showed that there was "no difference in overall survival between paclitaxel and irinotecan groups," and that "both are considered reasonable second-line treatment options," the authors stated.
They noted that the study population may not be generalizable, all patients received S-1 plus cisplatin as a first-line therapy, and that patients with severe peritoneal metastasis were excluded. They also noted the study was limited by small sample size.
Source: MedPage Today: http://www.medpagetoday.com/HematologyOncology/Chemotherapy/42709