Multicenter phase I clinical trial of daily and weekly RAD001 (everolimus) in combination with vinorelbine and trastuzumab in patients with HER-2-overexpressing metastatic breast cancer with prior resistance to trastuzumab.

Abstract

Abstract Abstract #406 Background: Resistance to trastuzumab (H) is associated with loss of PTEN and AKT/mTOR activation. Preclinically, RAD001, an oral inhibitor of mTOR, enhances the efficacy of H suggesting that RAD001 could reverse resistance to H.
 Methods: Vinorelbine (V) was administered at a dose of 25 mg/m2, IV over 10-15 min on days 1 and 8 q3w. H 4 mg/kg loading dose administered IV over 90 min on Day 1 (if pt was not already receiving H), followed by weekly H 2 mg/kg IV over 30 min. In the daily RAD001 arm, 3 cohorts were planned (2.5, 5 and 10mg) and in the weekly RAD001 arm, 4 cohorts were planned (20, 30, 50 and 70mg). Treatment continued until progression or unacceptable toxicity.
 Results: As of June 10 2008, 28 heavily pretreated pts were enrolled: 15 to 5mg/d, 6 to 20mg/w and 7 to 30mg/w cohorts. All pts received prior taxanes. Median number of prior CT regimens was 3 (range: 1-5). The main safety events were grade 2 and 3 stomatitis which led to dose reduction of RAD001 in 3 pts and dose interruption in 3. Grade 4 and 3 Neutropenia were seen in 24 pts (leading to dose reduction of V in 11 pts). Twenty two pts have been evaluated for efficacy (table 1). 1 pt had a CR (45+ weeks), 2 pts had PR (35+, 38 weeks), 15 pts SD (Median 26+, range 8+ to 58 weeks) and 4 pts PD. Clinical benefit rate (CR+PR+SD > 24 wks) is 55%+.
 Conclusions: Initial findings show that RAD001 is generally well tolerated in combination with V and H and shows promising anticancer activity and clinical benefit in heavily pretreated patients with HER2+ advanced breast cancer. Updated results will be presented.
 
 Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 406.