ASCO: Irinotecan-Platinum Boosts Survival in SCLC

CHICAGO, June 8 -- Irinotecan (Camptosar) plus carboplatin (Paraplatin) modestly extends survival for extensive-stage small cell lung cancer compared with a standard etoposide and carboplatin regimen, researchers found.
The irinotecan-based regimen significantly lengthened overall survival, though by only 1.4 months (8.5 versus 7.1 months, P=0.02), said Andreas Hermes, M.D., of Grosshansdorf Hospital in Grosshansdorf, Germany, and colleagues.
"Our study supports the use of carboplatin plus irinotecan as a standard chemotherapy regimen in extensive disease small cell lung cancer," Dr. Hermes reported at the American Society of Clinical Oncology meeting here.
Previous studies had shown conflicting results comparing irinotecan and etoposide in combination with cisplatin (Platinol).
To compare these combinations with carboplatin, the researchers conducted the multicenter IRIS study in Norway and Sweden.
The trial included 209 patients with histologically -- or cytologically -- confirmed extensive small cell lung cancer but no prior systemic chemotherapy or other types of cancer.
Patients were randomized to four cycles of carboplatin and either 175 mg/m2 irinotecan intravenously on day one every three weeks or 120 mg/m2 etoposide orally on days one to five every three weeks.
About 80% of patients in both groups received all four cycles. Dose was reduced by a third for patients older than 70 or who had poor performance status.
At one-year follow-up, 18 patients in the irinotecan group and seven patients in the etoposide group had complete remission (P=0.02).
One-year overall survival was 34% in the irinotecan group versus 24% in the etoposide group (hazard ratio 1.41, 95% confidence interval 1.06 to 1.87).
Median survival was also significantly longer with irinotecan (8.5 versus 7.1 months, P=0.02).
"Median survival was somewhat shorter than in other clinical trials, but we aimed at a clinically representative patient population," Dr. Hermes noted.
More than a third of the patients were over age 70; nearly half scored two to four on performance status. About half in both arms received second-line treatment.
Grade three to four toxicity with the two regimens was similar between groups except that thrombocytopenia tended to be lower with irinotecan (11% versus 26%, P=0.05) and diarrhea was more common (11% versus 1%, P=0.003).
Quality of life was not compromised by the irinotecan-carboplatin combination, Dr. Hermes said, although he did not present data on this outcome.
The irinotecan-carboplatin combination is at least as effective as etoposide and carboplatin, concluded Pieter E. Postmus, M.D., of Vrije Universiteit Medical Center in Amsterdam, who was a discussant for the study.
However, he noted, "I would conclude also that there are more data needed to change policy and to replace carboplatin and etoposide in extensive stage disease by a regimen containing irinotecan."
The study was supported by the Norwegian Cancer Society, Aventis, and Pfizer. The researchers disclosed no conflicts of interest. Dr. Postmus provided no information on conflicts of interest.Primary source: American Society of Clinical Oncology meetingSource reference: Hermes A, et al "A randomized phase III trial of irinotecan plus carboplatin versus etoposide plus carboplatin in patients with small cell lung cancer, extensive disease (SCLC-ED): IRIS-Study." ASCO 2007; Abstract 7523.