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MAP plus maintenance pegylated interferon α-2b (MAPIfn) versus MAP alone in patients with resectable high-grade osteosarcoma and good histologic response to preoperative MAP: First results of the EURAMOS-1 “good response” randomization.
Abstracts that were granted an exception in accordance with ASCO's Conflict of Interest Policy are designated with a caret symbol (^).
Background: EURAMOS-1 (NCT00134030) is an international randomized controlled trial investigating treatment optimization in osteosarcoma on the basis of histologic response to preoperative chemotherapy (CT). In patients (pts) with “good response” (GR; <10% viable tumor at surgery) to induction CT, efficacy of maintenance therapy with pegylated interferon α-2b (Ifn) was investigated. Methods: Pts ≤40yrs with resectable localized or primary metastatic high-grade extremity or axial osteosarcoma were eligible for registration at diagnosis. Eligibility for randomization included: [a] receipt of two cycles pre-op methotrexate, doxorubicin, cisplatin (MAP); [b] complete macroscopic resection of primary tumor; and [c] no disease progression. GR pts were randomized (1:1) after surgery to four cycles MAP +/-Ifn. Ifn (0.5-1.0 μg/kg/wk) was given after CT until 2yr post registration. Primary endpoint: event free survival (EFS); secondary: overall survival, toxicity. The trial design sought improved 3yr EFS from 70% to 80% (80% power, 2-sided alpha 5%). The final analysis was planned after 147 EFS events. Results: 2,260 pts were registered (Apr 05 to Jun 11) from 17 countries (326 sites) making it the largest trial in this rare cancer. GR was reported in 1,034 pts and 715 consented to randomization (358 MAP, 357 MAPIfn) with baseline characteristics balanced by arm: median age 14yr, 59% male, 79% localized disease. 271/357 (76%) pts started Ifn; main reason for not starting was treatment refusal, 66/86. By Feb 13 234/271 had stopped Ifn. Median duration of Ifn if started was 455 days; grade 3+ toxicity during Ifn reported by 81pts (30%). Median follow-up is 3.1yr with 174 EFS events reported: 93 MAP, 81 MAPIfn. Hazard ratio for EFS from adjusted Cox model was 0.82 (95% CI 0.61-1.11; p=0.201) in favor of MAPIfn. Conclusions: With current follow-up, EFS for MAPIfn is not statistically superior to MAP alone in pts with high-grade osteosarcoma and good response to pre-op MAP. One-quarter of pts did not start Ifn, which may have influenced this finding. Further follow-up for events and survival continues. Clinical trial information: NCT00134030.