Irinotecan Plus Cisplatin May Be a Promising Radiation Sensitizer, According to Phase II Study

OSAKA, Japan—Induction with irinotecan (Camptosar) and cisplatin (Platinol) followed by thoracic radiation combined with weekly irinotecan in patients with unresectable non–small-cell lung cancer (NSCLC) seems to be a feasible regimen in a cooperative group setting, according to the preliminary results of a phase II study presented in an ASCO abstract.

[“A phase II study of induction chemotherapy with irinotecan and cisplatin followed by thoracic radiation combined with weekly irinotecan in patients with unresectable stage III NSCLC.” Yamamoto N et al: Proc Am Soc Clin Oncol (abstract 1953)19:499a, 2000.]

Irinotecan may be a promising radiation sensitizer for locally advanced NSCLC, according to the Japanese research team. The overall response rate was 63% (5.9% had a complete response, and 57.4% a partial response). The estimated 1-year survival was 71.7%.

From February 1998 to January 1999, 68 patients were enrolled. Eligible patients had unresectable stage III NSCLC, performance status (PS) 0 or 1, and no prior therapy. There were 52 males and 16 females enrolled. Median age was 63 years. Twenty-two patients were PS 0 and 46 were PS 1. Within the group, 28 patients had stage IIIA cancer and 46 had stage IIIB cancer.

Patients received two cycles of irinotecan plus cisplatin as induction chemotherapy followed by weekly irinotecan with concomitant thoracic radiation, according to the following regimen: cisplatin 80 mg/m² on days 1 and 29, and irinotecan 60 mg/m² on days 1, 8, 15, 29, 36, and 43. Irinotecan 30 mg/m² on days 57, 64, 71, 78, 85, and 92. Thoracic radiation was initiated on day 57 at 2 Gy/d (total of 60 Gy).

Toxicities

Grade 3-4 toxicities during induction chemotherapy were primarily neutropenia (41%/31%). Grade 3-4 toxicities during concomittent irinotecan and thoracic radiation consisted of neutropenia (10%/6%); esophagitis (4%/0%); and hypoxia (4%/2%). There were no treatment-related deaths.

“The next step is to look at those in earlier stage disease,” said Dr. Alan Sandler, Vanderbilt University, in an ONI interview. “The investigators showed that it’s feasible and may prove to be an interesting combination. Obviously further study is warranted, particularly in randomized trials.”