Randomized Phase Iii Trial Comparing Vincristine, Actinomycin, Cyclophosphamide (Vac) With Vac/V Topotecan/Cyclophosphamide (Tc) For Intermediate Risk Rhabdomyosarcoma (Irrms). D9803, Cog Study

9509 Background: IRRMS was defined as nonmetastatic alveolar (A) RMS or undifferentiated sarcoma (UDS); stage (stg) 2 and 3, group (gr) III embryonal (E) RMS; stg 4 ERMS <10y. IRRMS had a 5 yr failure free survival (FFS) of 64% on IRS IV. Since T alone and with C has significant activity in RMS, we tested whether alternating VAC/VTC improved FFS for IRRMS compared with VAC alone. Methods: Patients (pts) < 50 y with IRRMS with adequate organ function were randomized to 39 wks of VAC (V=1.5 mg/m2, A=0.045 mg/kg, C=2.2 g/m2 q 3 wk) vs VAC alternating with VTC (T=0.75 mg/m2/d ×5, C=250 mg/m2/d ×5 q 3 wk), with additional wkly V; doses adjusted for age <3y; local therapy was after wk 12. Pts with parameningeal RMS/meningeal extension (PME) were nonrandomly treated with VAC and immediate XRT. Primary study endpoint was FFS. The study was designed with 80% power (5% 2-sided alpha level) to detect an increase in 5 yr FFS from 64% to 75%, a relative risk (RR) of 0.64, with VAC/VTC, requiring 518 randomized pts. Results reflect the 3rd of 4 planned analyses (75% information); O'Brien Fleming adjusted alpha level is 0.0166; and Cox PH model was used. Results: 620 eligible pts were entered from 9/99 to 8/05: 266 randomized to VAC, 253 to VAC/VTC, 101 PME patients were nonrandomly treated with VAC. Treatment strata were ERMS stg 2/3, gr III 37%; ERMS grp IV <10 y 6%; ARMS/UDS stg 1 or gr I 16%; ARMS/UDS other 25%; PME 16%. 3% of pts were <1 y, 69% 1–9 y, 28% ≥10 y; 13% of pts were stg 1; 26% stg 2; 54% stg 3; 7% stg 4. 77% pts had gr III tumors. Primary tumor sites were PM in 35% pts, extremity 15%, bladder/prostate 16%, retroperitoneal/perineal 15%, other 19%. Median follow up is 2.4 yrs. FFS at 2 yrs is 77% with VAC and 72% with VAC/VTC. Observed data are inconsistent with hypothesized improvement under VAC/VTC (RR=1.20, 98.34% CI: 0.78–1.85, p=0.3). Similar patients on IRS IV had 2 yr FFS of 77%. 2 yr survival (OS) with VAC: 91%; VAC/VTC: 87% (RR=0.94, CI: 0.55–1.59, p=0.8). There were 12 2nd malignancies and 10 deaths as first events. 4 of 10 deaths were from hepatopathy, which decreased in incidence following dose changes for A and C. Conclusions: In IRRMS, VAC/VTC does not significantly improve FFS nor OS versus VAC, and outcome is similar to IRS IV. No significant financial relationships to disclose.