- The final phase 3 results from MARIANNE show that trastuzumab emtansine (T-DM1) with or without pertuzumab has similar OS compared with trastuzumab with taxane among patients with human epidermal growth factor receptor 2 (HER2)-positive advanced breast cancer (aBCa).
- T-DM1 without pertuzumab (T-DM1+placebo) displayed greater tolerability.
Why this matters
- Previous results showed similar PFS across groups and greater tolerability of T-DM1+placebo.
- Authors conclude that T-DM1 is a first-line treatment for patients with metastatic HER2+ BCa who are considered unsuitable for taxane-based therapy.
- 1095 women in 38 countries were randomly assigned to T-DM1+placebo, T-DM1+pertuzumab, or taxane+trastuzumab (control group).
- OS was the primary outcome.
- Funding: F. Hoffmann-La Roche, Ltd.
- Median follow-up was approximately 54 months.
- Median OS was no different across groups (T-DM1+placebo, 53.7 months; T-DM1+pertuzumab, 51.8 months; and control group, 50.9 months). Compared with control, T-DM1+placebo had stratified HR, 0.93; 97.5% CI, 0.73-1.20 and T-DM1+pertuzumab had stratified HR, 0.86; 97.5% CI, 0.67-1.11.
- The median time to clinically meaningful deterioration in neurotoxicity symptoms was shorter in the control group (2.1 months) and T-DM1+pertuzumab group (4.2 months) than the T-DM1+placebo group (6.2 months).
- The T-DM1+placebo group had lower rates of alopecia, diarrhea, and fewer treatment-related adverse events.
- None were reported by the authors.