Abstract GS3-04: A randomized phase III study of adjuvant trastuzumab for a duration of 9 weeks versus 1 year, combined with adjuvant taxane-anthracycline chemotherapy, for early HER2-positive breast cancer (the SOLD study)
Authors: Joensuu H , Fraser J , Wildiers H , Huovinen R , Auvinen P , Utriainen M , Nyandoto P , Villman KK , Halonen P , Granstam-Björneklett H , Lundgren L , Yachnin J , Turpeenniemi-Hujanen T , Ritchie D , Huttunen T , Neven P , Canney P , Harvey VJ , Kellokumpu-Lehtinen P-L , Lindman H 
Published: February 2018

Background: The optimal duration of trastuzumab (T), when given together with chemotherapy and after chemotherapy as adjuvant treatment in patients with HER2+ breast cancer (BC), is unknown. Whilst the international standard is 12 months of T, the benefits and harms of T treatment continued beyond the chemotherapy are unclear.

Methods: Women with histologically confirmed node-negative or node-positive HER2+ BC were eligible for the trial (NCT00593697). The primary tumor diameter was required to be &gt;5 mm in node-negative cancer. Patients with distant metastases, inflammatory cancer, clinically significant cardiac disease, left ventricular ejection fraction (LVEF) &lt;50%, unknown estrogen receptor (ER) status, World Health Organization performance status &gt;1, and those who had received neoadjuvant systemic cancer therapy were excluded. Patients were randomly assigned to 2 groups prior to starting systemic cancer therapy. The initial systemic treatment was identical in the groups consisting of 3 cycles of 3-weekly docetaxel plus T followed by 3 cycles of fluorouracil, epirubicin, and cyclophosphamide (FE75C). Thereafter, no further T or chemotherapy was administered in Arm A, whereas in Arm B single-agent T was administered 3-weekly for 14 cycles to complete 1 year of T treatment. The docetaxel dose was either 80 mg/m2 or 100 mg/m2 (prespecified for each center). Radiation therapy and endocrine therapy (for patients with ER+ cancer) were given according to the institutional practice; the minimum scheduled duration of endocrine therapy was 5 years. The LVEF was measured pretreatment, and on study weeks 18, 31, 43, and 61 and month 36. The primary endpoint was disease-free survival (DFS) compared between the groups using a Cox model and the non-inferiority approach.

Results: A total of 2,176 patients were entered into the study from 63 centers in 7 countries from Jan. 3, 2008 to Dec.16, 2014. The median follow-up time was 5.2 years at data collection closure (Dec. 31, 2016). The efficacy and safety data will be presented at the meeting.

Citation Format: Joensuu H, Fraser J, Wildiers H, Huovinen R, Auvinen P, Utriainen M, Nyandoto P, Villman KK, Halonen P, Granstam-Björneklett H, Lundgren L, Yachnin J, Turpeenniemi-Hujanen T, Ritchie D, Huttunen T, Neven P, Canney P, Harvey VJ, Kellokumpu-Lehtinen P-L, Lindman H. A randomized phase III study of adjuvant trastuzumab for a duration of 9 weeks versus 1 year, combined with adjuvant taxane-anthracycline chemotherapy, for early HER2-positive breast cancer (the SOLD study) [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr GS3-04.