Dr McAndrew on the Evolving Treatment Armamentarium for HER2+ Breast Cancer

Nicholas P. McAndrew, MD, MSCE, health sciences clinical assistant professor, Hematology/Oncology, University of California, Los Angeles (UCLA), UCLA Health, discusses the necessity of sharing updates as the treatment armamentarium for HER2-positive breast cancer evolves and highlights the importance of the phase 3 HER2CLIMB-02 trial (NCT03975647).

The treatment paradigm for patients with breast cancer, particularly HER2-positive breast cancer, is in constant evolution with the emergence of new studies and updated analyses of existing studies, McAndrew begins. Staying informed about these developments is crucial, and forums such as the OncLive® State of the Science Summit™ (SOSS) meetings provide an ideal platform for keeping up with the latest advancements, he imparts. Notably, McAndrew and colleagues shared updates in the realm of breast cancer at one of the latest SOSS meetings. Furthermore, although the realm of updates in HER2-positive breast cancer management can be overwhelming, it is beneficial to focus on a few compelling and relevant studies, he adds.

The HER2CLIMB-02 study explored potential new roles for existing breast cancer drugs in patients with previously treated HER2-positive metastatic breast cancer. The agent tucatinib (Tukysa) gained FDA approval in the United States based on findings from the phase 2 HER2CLIMB study (NCT02614794), which demonstrated the superiority of the agent in combination with capecitabine and trastuzumab (Herceptin) over capecitabine plus trastuzumab alone, particularly in terms of progression-free survival (PFS) in the overall population of patients with previously treated HER2-positive metastatic breast cancer and in patients with brain metastases, McAndrew expands. Subsequent investigations have explored the use of tucatinib in various combinations, he notes.

In the second-line setting and beyond, the HER2CLIMB-02 study investigated tucatinib in combination with ado-trastuzumab emtansine (T-DM1; Kadcyla), McAndrew continues. The randomized trial compared T-DM1 plus placebo with T-DM1 plus tucatinib, with PFS as the primary end point, he states. In the tucatinib arm, 43.4% of patients had brain metastases, and 45.2% of patients had de novo metastatic disease, with a median of 1 prior line of therapy, he explains. The study revealed an improvement in PFS with tucatinib plus T-DM1 at 9.5 months (95% CI, 7.4-10.9) vs 7.4 months (95% CI, 5.6-8.1) with T-DM1 plus placebo, which were statistically significant results (HR, 0.76; 95% CI, 0.61-0.95; P = .0163), McAndrew concludes.