A phase III study exploring various doses of imatinib (IM) or IM in combination for newly diagnosed chronic phase (CP) chronic myeloid leukemia (CML) patients (pts): Results of an interim analysis of the SPIRIT trial of French CML group.

7058 Background: IM 400 mg daily is the front-line treatment of CP CML, but provides only 50% major molecular responses (MMR) at 18 months (Mo). We designed a phase III randomized multicenter open-label prospective trial comparing IM 400 mg/d (n=159) with 3 experimental arms: IM 600 mg/d (n=160), IM 400 mg/d + s/c cytarabine (Ara-C), (20 mg/m2/d, d15–28 of 28-day cycles) (n=158) and IM 400 mg/d + s/c Peg-IFN2a (90 μg/wk) (n=159). Pts were allocated at a 1.1.1.1 ratio, stratified by Sokal risk groups. Molecular assessments were centralized and blinded. An interim analysis of 636 pts was planned based on an IS BCR-ABL/ABL ratio <0.01% (Optimal Molecular Response, OMR) at 1 year (α=0.85%, β=10%). Results: 636 pts were recruited between 9/2003 and 10/2007, median age 51 (18–78) yrs, 62% males, median follow-up for alive pts 36 (12–62) Mo. At 3 Mo, 88% of pts achieved complete hematologic response. Complete cytogenetic response (CCyR), MMR and OMR rates are presented (Table). MMR rates at 6 and 12 Mo were high...